JP6119485B2 - Brake device for transmission - Google Patents

Description

  The technology disclosed herein relates to a brake device for a transmission.

  Patent Document 1 describes a brake device including a first piston and a second piston as a brake device for a transmission. Specifically, in this brake device, a hydraulic chamber for clearance adjustment is formed inside the first piston, and the second piston is inserted into the hydraulic chamber. As the hydraulic pressure is supplied to and discharged from the hydraulic chamber for adjusting the clearance, the second piston reciprocates in the axial direction relative to the first piston. On the other hand, the first piston is inserted into the transmission case, and reciprocates in the axial direction together with the second piston as the hydraulic pressure is supplied to and discharged from the pressing hydraulic chamber formed in the transmission case. .

  With such a configuration, in the brake device for the transmission described in Patent Document 1, the second piston member approaches the multi-plate brake as the hydraulic pressure is supplied to the second hydraulic chamber, and the second piston member The second piston member moves away from the multi-plate brake as the clearance between the multi-plate brake and the friction plate of the multi-plate brake becomes small and the hydraulic pressure is discharged from the second hydraulic chamber. It is possible to switch between a state in which the clearance between the plate brake and the friction plate is increased.

  Patent Document 2 also describes a brake device having a similar configuration. Specifically, the brake device includes a first piston and a second piston arranged in the axial direction of the transmission, and as the hydraulic pressure is supplied to the second hydraulic chamber, the second piston moves the first piston. Push from behind to move it closer to the multi-plate brake. This reduces the clearance between the first piston and the friction plate of the multi-plate brake. On the other hand, by discharging the hydraulic pressure from the second hydraulic chamber, the clearance between the first piston and the friction plate of the multi-plate brake is increased.

Japanese Patent Laid-Open No. 7-12221 JP 2005-265063 A

  By the way, in the brake device of the composition indicated in patent documents 1, the stopper member is provided in the 1st piston, and the 2nd piston which strokes when supplying oil pressure to the oil pressure room for clearance adjustment is this By contacting the stopper member, the stroke amount is regulated. However, the first piston becomes longer in the axial direction as much as the stopper member is provided, and as a result, the axial length of the brake device becomes longer.

  Moreover, in the brake device described in Patent Document 2, a stopper that restricts the stroke amount of the second piston is interposed between the first piston and the second piston arranged in the axial direction. Even in this configuration, the axial length of the brake device becomes longer as the stopper member is interposed.

  The technology disclosed herein has been made in view of such a point, and an object thereof is to regulate the stroke amount of the piston in the brake device of the transmission including the first piston and the second piston. It is to shorten the axial length of the brake device while providing the stopper member.

  The technology disclosed herein relates to a brake device for a transmission that engages and releases a multi-plate brake provided in a transmission case according to supply and discharge of hydraulic pressure.

  The brake device is inserted into the transmission case and is configured to move in the axial direction so as to be close to the multi-plate brake as the hydraulic pressure is supplied to the first hydraulic chamber, and The first piston and the multi-plate brake are interposed between the first piston and the first hydraulic chamber so as to move together with the first piston in a direction approaching the multi-plate brake. The first piston is configured to move relative to the first piston in the direction approaching the multi-plate brake in accordance with the supply of the hydraulic pressure to the second hydraulic chamber partitioned from the first piston. 2 pistons.

  An oil passage for supplying and discharging hydraulic pressure to and from the second hydraulic chamber is opened on an inner peripheral surface of the transmission case, and the first piston has an oil passage at an intermediate position in the axial direction. 2 An opening for communicating the hydraulic chamber and the oil passage is provided.

  Then, on the inner peripheral surface of the transmission case, the first piston is brought into contact with the edge of the opening when the first piston moves in a direction close to the multi-plate brake. A stopper member for regulating the position of the piston is attached.

  According to this configuration, when the hydraulic pressure is supplied to the first hydraulic chamber, both the first and second pistons move in the axial direction so as to be close to the multi-plate brake. On the other hand, when the hydraulic pressure is supplied to the second hydraulic chamber, only the second piston moves in the axial direction so as to be close to the multi-plate brake.

  Therefore, this brake device can bring the second piston close to the multi-plate brake by supplying hydraulic pressure to the second hydraulic chamber, thereby making the clearance between the second piston and the multi-plate brake zero (hereinafter, referred to as “the second piston”). This state is also called zero clearance state). In this zero clearance state, by supplying hydraulic pressure to the first hydraulic chamber, both the first and second pistons are brought close to the multi-plate brake, and the multi-plate brake is pressed by the second piston. The plate brake can be fastened.

  In contrast to this, the brake device supplies the first hydraulic chamber with hydraulic pressure so that the first and second pistons are both brought close to the multi-plate brake to be in a zero clearance state, and then the second By supplying hydraulic pressure to the hydraulic chamber, only the second piston may be brought closer to the multi-plate brake and the multi-plate brake may be fastened.

  In any configuration, since it is a two-stage stroke configuration in which a zero-clearance state can be set in advance and a multi-plate brake can be fastened therefrom, responsiveness when the multi-plate brake is fastened is enhanced.

  In the above configuration, the oil passage for supplying and discharging the hydraulic pressure to the second hydraulic chamber defined between the first piston and the second piston is opened on the inner peripheral surface of the transmission case. An opening communicating with the opening of the oil passage is provided at an intermediate position in the axial direction of the first piston. The hydraulic oil supplied through the oil passage flows into and out of the second hydraulic chamber through an opening provided in the first piston.

  A stopper member is attached to the inner peripheral surface of the transmission case. When the hydraulic pressure is supplied to the first hydraulic chamber, when the first piston moves in the direction approaching the multi-plate brake, the edge of the opening provided in the first piston comes into contact with the stopper member. The first piston is restricted from moving further.

  In this way, the stopper member that restricts the position of the first piston, in other words, restricts the stroke amount of the first piston, hits the edge of the opening provided at the intermediate position in the axial direction of the first piston. Accordingly, each of the stopper member and the receiving portion thereof is located at an intermediate position in the axial direction of the first piston, and these utilize a configuration necessary for supplying and discharging hydraulic pressure to and from the second hydraulic chamber. . Such a configuration allows the stopper member and its receiving portion to be shifted in the axial direction with respect to the first piston so that the axial length of the brake device can be shortened as compared with a configuration separately provided. Become.

  The transmission case is recessed from an inner peripheral surface thereof and has a groove extending in the circumferential direction, the stopper member is fixed in the groove, and the oil passage is It is good also as providing in the position which overlaps with the said axial direction with respect to a ditch | groove, and communicating with the said ditch | groove.

  By doing so, the concave groove can function as a part of a flow path for supplying hydraulic pressure into the second hydraulic chamber through an opening provided in the first piston by communicating with the oil passage. By fixing the stopper member in the concave groove constituting a part of the flow path, the axial length of the brake device can be shortened as compared with the case where the stopper member is separately provided.

  Also, the axial length of the brake device can be shortened by providing the oil passage and the concave groove at a position overlapping in the axial direction. It should be noted that at least a portion of the oil passage and the groove should overlap in the axial direction.

  The stopper member is a C-type snap ring that has a cut and is fitted in the concave groove, and a communicating portion between the oil passage and the concave groove has an end of the cut of the C-type snap ring. It is good also as the latching member which maintains that the said cut | interruption of the said C-type snap ring is located in the communicating part of the said oil path and the said ditch | groove by engaging with each.

  When the stopper member is constituted by a C-shaped snap ring that fits inside the groove, the snap ring breaks so that the opening of the oil passage communicating with the groove is not blocked by the snap ring. It is preferable to set the rotation angle of the snap ring in the concave groove so as to be located at the opening position.

  On the other hand, even if the rotation angle of the snap ring is set in such a manner, the snap ring rotates in the concave groove due to vibration during traveling of the vehicle, and the opening of the oil passage is There is a possibility of being blocked by the snap ring.

  Therefore, it is preferable to attach a locking member that locks the C-shaped snap ring to the communicating portion between the oil passage and the recessed groove. The locking member is disposed in the communication portion between the oil passage and the concave groove and engages with each of the ends of the cut of the C-shaped snap ring so that the cut is in the communication portion between the oil passage and the concave groove. Maintaining position. The locking member may be a member that restricts the rotation of the snap ring within the groove, but the snap ring breaks between the oil passage and the groove even if the rotation of the snap ring is not completely prohibited. The snap ring may be allowed to rotate as long as it is located at the communicating portion with the.

  By this locking member, the stopper member is prevented from blocking the opening of the oil passage, and it is possible to smoothly supply and discharge hydraulic pressure to and from the second hydraulic chamber. This increases the controllability of the brake device.

  As described above, according to the brake device of the transmission, in the brake device including two pistons, that is, the first piston and the second piston, the stopper member that restricts the stroke amount of the first piston is the first member. The receiving portion that is disposed at an intermediate position in the axial direction of the piston and is in contact with the stopper member is constituted by the edge of the opening of the second hydraulic chamber provided in the first piston, so that the stopper member and the receiving portion thereof are received. It is possible to shorten the axial length of the brake device as compared with a configuration in which the portion is shifted in the axial direction with respect to the first piston and separately disposed.

It is a skeleton diagram of an automatic transmission. It is a fastening table | surface of an automatic transmission. It is a block diagram which shows the hydraulic path from the oil pump of an automatic transmission to a friction engaging element. It is sectional drawing which shows the structure of the LR brake of an automatic transmission. FIG. 5 is a view corresponding to FIG. 4 showing a standby state of the LR brake. FIG. 5 is a diagram corresponding to FIG. 4 illustrating a state in which the LR brake is engaged. It is a disassembled perspective view which shows the 1st-3rd piston member of LR brake. It is sectional drawing which expands and shows the vicinity of the oil path which supplies and discharges hydraulic pressure to LR brake. It is sectional drawing which expands and shows the vicinity of the sealing member attached to the outer periphery part of a 3rd piston member. It is a cross-sectional view of a transmission case showing a stopper member fixed in a concave groove of the transmission case and a locking member disposed in a communication portion between the concave groove and the oil passage. It is sectional drawing which shows the ditch | groove formed in the internal peripheral surface of a transmission case. It is a perspective view which shows a locking member. It is the front view and side view which show the modification of a locking member.

  An embodiment of a transmission braking device will be described with reference to the drawings. The brake device according to the following description is an example.

(1) Overall Configuration FIG. 1 is a skeleton diagram of an automatic transmission. The automatic transmission 1 is mounted on a horizontally mounted automobile such as a front engine front drive vehicle, for example, and includes a transmission mechanism 2 and a transmission case 3 that houses the transmission mechanism 2. The engine output rotation is input to the input shaft 4 of the speed change mechanism 2 via a torque converter (not shown). The output rotation of the speed change mechanism 2 is taken out from the output gear 5 and transmitted to the drive wheels via a differential device (not shown).

  The speed change mechanism 2 includes a first planetary gear set 10, a second planetary gear set 20, and a third planetary gear set 30. These constitute the power transmission path of the speed change mechanism 2 and are arranged coaxially on the axis of the input shaft 4 in this order from the engine side.

  The transmission mechanism 2 further includes a low clutch 40 and a high clutch 50, an LR brake (low reverse brake) 60, a 2-6 brake 70, and an R-3-5 brake 80. These are friction engagement elements, and are arranged coaxially on the axis of the input shaft 4 in the above order from the engine side.

  The first planetary gear set 10 and the second planetary gear set 20 are a single pinion type, and the third planetary gear set 30 is a double pinion type. Each planetary gear set 10, 20, 30 has sun gears 11, 21, 31, and pinions 12, 22, 32 (inner pinion in the case of the third planetary gear set 30) that mesh with the sun gears 11, 21, 31. The internal gears 14, 24, 34 that mesh with the carriers 13, 23, 33 that support the pinions 12, 22, 32 and the pinions 12, 22, 32 (the outer pinion in the third planetary gear set 30). And.

  The sun gear 11 of the first planetary gear set 10 and the sun gear 21 of the second planetary gear set 20 are coupled, and are further coupled to the input shaft 4 via the low clutch 40 so as to be freely connected and disconnected.

  The internal gear 14 of the first planetary gear set 10 and the carrier 23 of the second planetary gear set 20 are connected to each other, and further connected to the input shaft 4 via the high clutch 50 so as to be freely connected and disconnected, and the LR brake 60 It is connected to the transmission case 3 via the connection.

  The internal gear 24 of the second planetary gear set 20 and the internal gear 34 of the third planetary gear set 30 are connected, and are further connected to the transmission case 3 via a 2-6 brake 70 so as to be freely connected and disconnected.

  The carrier 33 of the third planetary gear set 30 is connected to the transmission case 3 via the R-3-5 brake 80 so as to be freely connected and disconnected, and the sun gear 31 of the third planetary gear set 30 is connected to the input shaft 4 to thereby connect the first planetary gear. The carrier 13 of the set 10 is connected to the output gear 5.

  In the automatic transmission 1, as shown in the fastening table of FIG. 2 (◯ indicates fastening), the frictional fastening elements 40, 50, 60, 70, and 80 are selectively fastened, whereby the planetary gear set 10. , 20, 30 are switched to achieve forward 1st to 6th speed and reverse speed.

  At the first forward speed, which is one of the start gears, the low clutch 40 and the LR brake 60 are engaged. In the second forward speed, the low clutch 40 and the 2-6 brake 70 are engaged. At the third forward speed, the low clutch 40 and the R-3-5 brake 80 are engaged. At the fourth forward speed, the low clutch 40 and the high clutch 50 are engaged. At the fifth forward speed, the high clutch 50 and the R-3-5 brake 80 are engaged. At the sixth forward speed, the high clutch 50 and the 2-6 brake 70 are engaged. The LR brake 60 and the R-3-5 brake 80 are engaged at a reverse speed, which is one of the start gears.

  FIG. 3 shows a hydraulic path. The hydraulic pressure discharged from the oil pump is adjusted to a predetermined line pressure (indicated by “PL” in the figure) by a regulator valve (not shown), and then the dedicated oil is supplied. It is always supplied to the hydraulic circuit 200 via the path, and is supplied to the hydraulic circuit 200 via the manual valve 140 when the D range or R range is selected.

  The hydraulic circuit 200 includes a first linear solenoid valve (hereinafter, the solenoid valve is referred to as “SV”) 121, a second linear SV 122, an on / off SV 123, and a shift valve 130. The first linear SV 121 is for supplying hydraulic pressure to the hydraulic chamber of the low clutch 40. The second linear SV 122 is for supplying hydraulic pressure to the A chamber 61 (pressing hydraulic chamber, second hydraulic chamber) of the LR brake 60 described later. The on / off SV 123 is for switching the position of the spool of the shift valve 130. The shift valve 130 communicates or blocks the second linear SV 122 and the A chamber 61, and a predetermined line pressure supply oil passage 124 and a B chamber 62 (clearance adjusting hydraulic chamber, first chamber) of an LR brake 60 described later. 1 hydraulic chamber). The spool of the shift valve 130 is always urged to the left with respect to FIG. 3 by a return spring (not shown). An A chamber oil passage 63 is provided between the shift valve 130 and the A chamber 61, and a B chamber oil passage 64 is provided between the shift valve 130 and the B chamber 62.

  The on / off SV 123 is a normally open type. Therefore, the on / off SV 123 outputs hydraulic pressure in the non-energized state (off), and the spool of the shift valve 130 is positioned on the right side in FIG. The first and second linear SVs 121 and 122 are normally closed types. Therefore, the first and second linear SVs 121 and 122 do not supply hydraulic pressure to the corresponding frictional engagement elements, that is, the low clutch 40 and the LR brake 60 in the non-energized state (off).

(2) Structure of LR Brake Next, the structure of the LR brake 60 will be described with reference to FIGS. 4, 5, and 6, the right side is the engine side and the left side is the anti-engine side. Note that the LR brake 60 is disposed in the vicinity of the output gear 5 disposed at the axial intermediate position of the automatic transmission 1. Reference numeral 3 b in FIG. 4 and the like denotes a boss that supports the output gear 5. Part.

  As shown in FIG. 4, the LR brake 60 includes two hydraulic chambers (A chamber 61 and B chamber 62), two pistons (pressing piston 65 and clearance adjusting piston 66) as main components. A multi-plate brake 69 including a plurality of friction plates (drive plate 69a and driven plate 69c) is provided. The pressing piston 65 and the clearance adjusting piston 66 are arranged coaxially on the axis of the input shaft 4, and the pressing piston 65 is fitted in the clearance adjusting piston 66. The pressing piston 65 is interposed between the clearance adjusting piston 66 and the multi-plate brake 69. The A chamber 61 is defined between the pressing piston 65, the clearance adjusting piston 66, and the transmission case 3, and the B chamber 62 is defined between the clearance adjusting piston 66 and the transmission case 3. It is formed.

  The plurality of drive plates 69a and the plurality of driven plates 69c are alternately arranged in the axial direction. The drive plate 69a is spline-engaged with the outer peripheral surface of the internal gear 14 (see FIG. 1) of the first planetary gear set 10 (not shown in FIG. 4). Facing 69b is stuck on both sides of drive plate 69a. The driven plate 69 c is spline-engaged with the inner surface spline portion 3 e of the transmission case 3. A retaining plate 69d is further spline-engaged with the inner surface spline portion 3e. The retaining plate 69d is restricted from moving toward the non-engine side by a snap ring 69e.

  The friction plates 69 a and 69 c of the multi-plate brake 69 are disposed between the retaining plate 69 d and the pressing piston 65. The friction plates 69a and 69c are restricted from moving toward the non-engine side by a retaining plate 69d.

  A return spring 164 is disposed on the outer peripheral side in the radial direction with respect to the multi-plate brake 69. Although not shown, a plurality of return springs 164 are provided at equal intervals in the circumferential direction. In this way, the return spring 164 is disposed radially outward with respect to the multi-plate brake 69, and the multi-plate brake 69 and the return spring 164 are disposed so as to overlap in the axial direction, thereby the LR brake. The axial length of 60 can be shortened.

  One end portion of each return spring 164 extending in the axial direction (that is, the end portion on the opposite engine side) is supported by a spring retainer 69f. The spring retainer 69f is located at a step provided at the outer peripheral edge of the retaining plate 69d and so as to be thinner than the inner peripheral side. In this way, the spring retainer 69f and the retaining plate 69d are disposed so as to overlap in the axial direction, whereby the axial length of the LR brake 60 is shortened. Note that the other end portion (that is, the end portion on the engine side) of each return spring 164 is supported by the second piston member 672 of the clearance adjustment piston 66 as described later.

  The clearance adjusting piston 66 is inserted in the transmission case 3 and is reciprocally movable in the axial direction. The clearance adjusting piston 66 is adjacent to the non-engine side of the first piston member 671, and the first piston member. 671 and a second piston member 672 that can reciprocate in the axial direction. As shown in FIG. 7, both the first piston member 671 and the second piston member 672 have an annular shape when viewed in the axial direction.

  Of these, the first piston member 671 has an outer peripheral end protruding toward the anti-engine side, a subsequent outer peripheral portion expanding toward the engine side, an intermediate portion expanding toward the anti-engine side, and an inner peripheral portion extending toward the engine side. And the inner peripheral end protrudes toward the non-engine side. The outer peripheral end portion of the first piston member 671 constitutes an edge portion 674 of the opening portion 612 of the A chamber 61 communicating with the A chamber oil passage 63 as described later. The opening edge portion 674 has a function as a receiving portion that abuts against a stopper member 160 described later and prevents the first piston member 671 from moving further to the counter-engine side. Further, the outer periphery of the first piston member 671 is provided with a side wall 675 (see also FIGS. 7 and 8) that faces the non-engine side and partitions the A chamber 61 as will be described later. Further, the inner peripheral end portion of the first piston member 671 constitutes a sliding surface on which a third inner peripheral seal member 686 of the third piston member 673 described later slides.

  A first outer peripheral seal member 681 and a first inner peripheral seal member 682 are oil-tightly attached to the outer peripheral end and the inner peripheral end of the first piston member 671, respectively. The first outer peripheral seal member 681 is a lip seal, is in contact with the inner peripheral surface of the transmission case 3, and can slide on the inner peripheral surface. The first inner peripheral seal member 682 is also a lip seal, and abuts against the wall surface of the recess 3a provided in the transmission case 3 and can slide on the wall surface. Thus, a B chamber 62 isolated by the first outer peripheral seal member 681 and the first inner peripheral seal member 682 is defined between the first piston member 671 and the transmission case 3. The first outer peripheral seal member 681 isolates the B chamber 62 from the A chamber 61, and the first inner peripheral seal member 682 isolates the B chamber 62 from the transmission case 3. The first piston member 671 reciprocates in the axial direction according to the supply and discharge of the hydraulic pressure to the B chamber 62.

  As shown in FIG. 7, the second piston member 672 is configured such that its inner diameter is larger than the inner diameter of the first piston member 671. The inner peripheral end of the second piston member 672 extends in a predetermined range in the radial direction and constitutes a contact end 676 that contacts the side wall 675 of the first piston member 671. The second piston member 672 has a shape in which an intermediate portion continuous with the contact end portion 676 has the same diameter and extends in the axial direction, and an outer peripheral portion has a larger diameter than the intermediate portion and extends in the axial direction. Yes. The outer periphery of the second piston member 672 is opposed to the opening edge 674 of the first piston member 671 in the axial direction, and the opening of the A chamber 61 communicated with the opening edge 674 and the oil passage 63 for the A chamber. The edge part of the part 612 is comprised. The opening 612 of the A chamber 61 is provided over the entire circumference between the first piston member 671 and the second piston member 672.

  The intermediate portion of the second piston member 672 is disposed so as to face the opening 674 of the A chamber 61 at a radially inward position, whereby the A chamber 61 is divided in the radial direction. A plurality of through holes 677 are formed in the middle portion of the second piston member 672 so as to communicate the inside and outside of the second piston member 672 dividing the inside of the A chamber 61 in the radial direction at equal intervals in the circumferential direction. (See also FIG. 7).

  As shown in FIG. 7, a plurality of retainer portions 678 that support the other end of the return spring 164 are also provided on the outer peripheral edge of the second piston member 672 at equal intervals in the circumferential direction. It is provided so that it may protrude radially toward the direction.

  A second outer peripheral seal member 683 is oil-tightly attached to the outer peripheral portion of the second piston member 672. The second outer peripheral seal member 683 is also a lip seal in the same manner as the first outer peripheral seal member 681 attached to the first piston member 671. The second outer peripheral seal member 683 contacts the inner peripheral surface of the transmission case 3 and slides on the inner peripheral surface. It is possible to move. The second outer peripheral seal member 683 isolates the A chamber 61 from the transmission case 3.

  A rubber blocking member 684 is attached to the abutting end 676 of the second piston member 672. The blocking member 684 has a function of blocking hydraulic fluid from communicating between the abutting end 676 and the side wall 675 by being in close contact with the side wall 675 of the first piston member 671. The blocking member 684 is oil-tightly configured between the contact end 676 and the side wall 675. In addition, as long as this oil tight function is obtained, not only the structure which attaches the rubber | gum blocking member 684 to the contact edge part 676 but various structures can be employ | adopted.

  As shown in FIG. 7, the pressing piston 65 is configured by an annular third piston member 673 as viewed in the axial direction. As shown in FIG. 4, the third piston member 673 has a shape such that the outer peripheral portion bulges away from the engine, the intermediate portion expands in the radial direction, and the inner peripheral portion bulges out toward the engine. Yes. The outer peripheral portion of the third piston member 673 has a function of pressing the multi-plate brake 69 by hitting the friction plate 69 c of the multi-plate brake 69.

  A third outer peripheral seal member 685 and a third inner peripheral seal member 686 are oil-tightly attached to the outer peripheral end portion and the inner peripheral end portion of the third piston member 673, respectively. The third outer peripheral seal member 685 is a lip seal, is in contact with the inner periphery of the second piston member 672, and can slide on the surface. The third inner peripheral seal member 686 is also a lip seal, and abuts on the inner peripheral end of the first piston member 671 and can slide on the surface. The third outer peripheral seal member 685 and the third inner peripheral seal member 686 isolate the A chamber 61 and the transmission case 3 from each other.

  Thus, between the first piston member 671, the second piston member 672, the third piston member 673, and the transmission case 3, the first outer peripheral seal member 681, the second outer peripheral seal member 683, the third outer peripheral seal member 685, and The A chamber 61 isolated by the third inner peripheral seal member 686 is partitioned. The third piston member 673 reciprocates in the axial direction relative to the first and second piston members 671 and 672 in accordance with the supply and discharge of the hydraulic pressure to the A chamber 61.

  Therefore, the first outer peripheral seal member 681 of the first piston member 671 corresponds to a first seal member that separates the A chamber 61 and the B chamber 62, and the second outer peripheral seal member 683 of the second piston member 672 is The third outer peripheral seal member 685 of the third piston member 673 is more radially inner than the second outer peripheral seal member 683, which corresponds to a second seal member that isolates the A chamber 61 and the transmission case 3 from each other. This corresponds to a third seal member that separates the A chamber 61 from the transmission case 3 on the side. Note that the hydraulic pressure in the B chamber 62 acts on the engine side of the first outer peripheral seal member 681 of the first piston member 671, and the hydraulic pressure in the A chamber 61 acts on the opposite side of the engine. As will be described later, the hydraulic pressure in the B chamber 62 is a line pressure, the hydraulic pressure in the A chamber 61 is a control hydraulic pressure lower than the line pressure, and when the multi-plate brake 69 is engaged, the line pressure is first applied to the B chamber 62. After the supply, the control oil pressure is supplied to the A chamber 61, and when the multi-plate brake 69 is released, the control oil pressure in the A chamber 61 is first released, and then the line pressure in the B chamber 62 is released. . Therefore, the lip seal constituting the first outer peripheral seal member 681 is set in a direction in close contact with the inner peripheral surface of the transmission case 3 when a relatively high hydraulic pressure in the B chamber 62 is applied.

  As shown in FIG. 4, the A chamber oil passage 63 led from the shift valve 130 passes through the wall of the transmission case 3 in the radial direction, and the A chamber oil passage 63 is connected to the transmission case. 3 is open to the inner peripheral surface. The A chamber oil passage 63 is actually formed so as to extend upward from below at the bottom of the transmission case 3 as shown in FIG. 10, but in FIG. An oil passage 63 for room A is drawn at the top of the machine case 3.

  The opening of the oil passage 63 for the A chamber is in a radial direction with respect to the opening 612 of the A chamber 61 formed between the opening edge portion 674 of the first piston member 671 and the outer peripheral portion of the second piston member 672. Relative. Thus, the first outer peripheral seal member 681 attached to the outer peripheral end of the first piston member 671 is positioned on the engine side with respect to the opening of the oil passage 63 for the A chamber, and is attached to the outer peripheral portion of the second piston member 672. The second outer peripheral seal member 683 thus positioned is located on the opposite side of the engine from the opening of the A chamber oil passage 63.

  On the inner peripheral surface of the transmission case 3, as shown in FIG. 11, a concave groove 610 recessed from the inner peripheral surface is formed continuously in the circumferential direction. As is apparent from FIG. 8, the A chamber oil passage 63 is disposed at a position overlapping the concave groove 610 in the axial direction, and the A chamber oil passage 63 communicates with the concave groove 610. . As will be described later, the concave groove 610 is inserted into the outer peripheral end of the first piston member 671 when the first piston member 671 is inserted into the transmission case 3 from the non-engine side toward the engine side and assembled to the transmission case 3. It is a groove provided for guiding the mounted first outer peripheral seal member 681 to the inner peripheral surface of the transmission case 3. As shown in FIGS. 8 and 11, a taper 611 that guides the first outer peripheral seal member 681 to the inner peripheral surface of the transmission case 3 is provided at the engine-side edge of the concave groove 610.

  A stopper member 160 that restricts the stroke amount of the first piston member 671 is fixed to the concave groove 610. The stopper member 160 is a C-shaped snap ring having two end portions 161 and 161 and having a break between them as shown in FIG. The stopper member 160 is fitted into the concave groove 610 at a position in the concave groove 610 that contacts the side wall on the non-engine side. An inner peripheral end portion of the stopper member 160 protrudes inward in the radial direction from the concave groove 610, and is configured by an opening edge portion 674 of the first piston member 671 and an outer peripheral portion of the second piston member 672. It is located in the opening 612 of the A chamber 61. As virtually shown in FIG. 8, when the first piston member 671 moves to the anti-engine side, the opening edge portion 674 of the first piston member 671 contacts the stopper member 160. This restricts the first piston member 671 from moving further, and as a result, the stroke amount of the first piston member 671 becomes a predetermined amount.

  As shown in FIG. 10, the stopper member 160 also has rotational angles (that is, each end portion 161 of the snap ring positioned on both sides in the circumferential direction across the A chamber oil passage 63 opened in the recessed groove 610). It is disposed in the groove 610 so as to be in phase. By doing so, the break of the snap ring is located at the position of the opening of the A chamber oil passage 63, so that the opening is not blocked by the snap ring, and the operation from the A chamber oil passage 63 to the A chamber 61 is performed. The oil can be supplied smoothly.

  A stopper member 160 made of a C-shaped snap ring is rotated in the groove 610 at the communicating portion between the chamber A oil passage 63 and the groove 610 so that the opening of the chamber A oil passage 63 is not blocked. A locking member 162 is attached. As shown in FIG. 12, the locking member 162 includes an insertion portion 1621 inserted into the oil passage 63 for the A chamber, and an interference portion 1622 that is continuous with the insertion portion 1621 and is disposed in the groove 610. 1622. The locking member 162 is configured by bending a belt-like plate having a relatively narrow width so as to have a predetermined shape. As a result, the interior of the locking member 162 is a space, and even when the locking member 162 is disposed in the communication portion between the A chamber oil passage 63 and the concave groove 610, the hydraulic oil is retained by the locking member 162. It is possible to flow smoothly through the internal space.

  The insertion portion 1621 is composed of two narrow plates that are arranged in parallel to each other and extend in the vertical direction, and an engaging portion that bulges in a direction away from each other at the lower end of the insertion portion 1621. 1623 is provided. The engaging portion 1623 engages with the inner wall of the oil passage 63 by the elastic restoring force of the insertion portion 1621 acting in a direction away from each other, and fixes the locking member 162 to the A chamber oil passage 63. Even when the top and bottom of the transmission case 3 is reversed when the automatic transmission 1 is assembled, the engaging member 162 inserted into the A chamber oil passage 63 is separated from the A chamber oil passage 63 by the engagement portion 1623. It is prevented from falling out.

  The interference part 1622 is disposed so as to extend from the upper end of the insertion part 1621 to both the left and right sides. When the insertion portion 1621 of the locking member 162 is inserted into the A chamber oil passage 63, the two interference portions 1622 are inserted in the circumferential direction from the opening of the A chamber oil passage 63, as shown in FIG. 10. They are arranged so as to extend in opposite directions. The interference portion 1622 hits the end portion 161 of the concave groove 610 when the C-shaped snap ring rotates. As a result, the C-type snap ring is prevented from further rotating, so that the snap ring break is always located at the position of the opening of the oil passage 63, and the stopper member 160 allows the A chamber to be positioned. It is avoided in advance that the opening of the oil passage 63 is blocked.

  As shown in FIG. 8, the locking member 162 is configured to have a smaller axial thickness than the stopper member 160. Thus, even when the first piston member 671 contacts the stopper member 160, the first piston member 671 does not hit the locking member 162. The locking member 162 does not affect the stroke of the first piston member 671, and the first piston member 671 reliably strokes with a predetermined stroke amount.

  The shape of the locking member is not limited to the shape shown in FIG. For example, FIG. 13 shows a deformation of the locking member 163 formed by bending a wire having a circular cross section into a predetermined shape including the insertion portion 1631, the interference portion 1632, and the engagement portion 1633, as in FIG. An example is shown. Even such a locking member can exhibit the function of preventing the stopper member 160 from rotating.

  Further, the B chamber oil passage 64 led from the shift valve 130 passes through the wall of the transmission case 3 and opens on the side surface in the transmission case 3 as shown in FIG. Thus, the B chamber oil passage 64 communicates with the B chamber 62. Although the illustration of the B chamber oil passage 64 is omitted, in reality, the B chamber oil passage 64 is formed to extend upward from below at the bottom of the transmission case 3 as in the A chamber oil passage 63. 4 and the like, for easy understanding, a B chamber oil passage 64 is drawn at the top of the transmission case 3 so as to extend in the axial direction.

(3) Operation of LR brake Next, the operation of the LR brake 60 will be described.

(I) Release State When the LR brake 60 is in the release state, hydraulic pressure is not supplied to the A chamber 61 and the B chamber 62. As a result, as shown in FIG. 4, the clearance adjustment piston 66 is moved away from the multi-plate brake 69 by the urging force of the return spring 164. Further, since the pressing piston 65 is fitted in the clearance adjusting piston 66, it moves together with the clearance adjusting piston 66 to the side away from the multi-plate brake 69. The clearance adjusting piston 66 is stopped by the outer peripheral portion of the first piston member 671 bulging toward the engine contacting the side wall of the transmission case 3. In the example shown in FIG. 4, the pressing piston 65 is stopped by the intermediate portion extending in the radial direction of the third piston member 673 coming into contact with the intermediate portion of the first piston member 671 that bulges toward the non-engine side. The second piston member 672 is in contact with the side wall 675 of the first piston member 671 at the contact end 676 thereof.

  The position of the pressing piston 65 and the position of the clearance adjusting piston 66 in this released state are the initial position of the pressing piston 65 and the initial position of the clearance adjusting piston 66, respectively. The initial position of the clearance adjusting piston 66 is structurally constant, but the relative position of the pressing piston 65 with respect to the clearance adjusting piston 66 varies depending on the zero clearance position described later. The initial position of the piston 65 is not constant. However, here, when the initial position of the pressing piston 65 is structurally located at the position farthest from the multi-plate brake 69 (that is, as illustrated in FIG. 4, the intermediate portion of the third piston member 673 is the first position). The case where the first piston member 671 is in contact with the intermediate portion) will be described.

(Ii) At the time of engagement-to the standby position When the released LR brake 60 is engaged, first, in the state where the pressing piston 65 and the clearance adjustment piston 66 are positioned at the initial positions, respectively, Hydraulic pressure is supplied. Line pressure is supplied to the B chamber 62. As a result, as shown in FIG. 5, the clearance adjustment piston 66 moves to the anti-engine side, and the pressing piston 65 fitted in the clearance adjustment piston 66 also moves to the anti-engine side. To do. Thus, both the pressing piston 65 and the clearance adjusting piston 66 are stroked so as to be close to the multi-plate brake 69. At this time, the clearance adjusting piston 66 strokes while the return spring 164 is contracted, that is, against the urging force of the return spring 164.

  The clearance adjusting piston 66 is stopped by the outer peripheral end protruding toward the non-engine side, that is, the opening edge 674 of the first piston member 671 abuts on the stopper member 160 attached to the inner peripheral surface of the transmission case 3. . In the example of FIG. 5, the pressing piston 65 is stopped while maintaining the state where the radially extending intermediate portion is in contact with the intermediate portion of the clearance adjusting piston 66. That is, the position of the pressing piston 65 and the position of the clearance adjusting piston 66 when the stroke of the clearance adjusting piston 66 ends are the standby position of the pressing piston 65 and the standby position of the clearance adjusting piston 66, respectively. .

  As described above, since the relative position of the pressing piston 65 with respect to the clearance adjusting piston 66 varies in accordance with the zero clearance position, the standby position of the clearance adjusting piston 66 is structurally constant. The standby position of the pressing piston 65 is not constant. However, here, the case where the intermediate portion of the pressing piston 65 is in contact with the intermediate portion of the clearance adjusting piston 66 will be described.

(Iii) At the time of fastening-to the pressing completion position Next, hydraulic pressure is supplied to the A chamber 61 in a state where the pressing piston 65 and the clearance adjusting piston 66 are positioned at the standby positions. The A chamber 61 is supplied with a control hydraulic pressure that is adjusted to be lower than the line pressure. Since the line pressure higher than that of the A chamber 61 is supplied to the B chamber 62, the clearance adjusting piston 66 does not move to the engine side, and the hydraulic pressure supplied to the A chamber 61 as shown in FIG. Only the pressing piston 65 strokes toward the side close to the multi-plate brake 69. The pressing piston 65 strokes without being affected by the return spring 164.

  In the pressing piston 65, the outer peripheral portion of the third piston member 673 that bulges away from the engine presses the friction plates 69 a and 69 c. The pressing piston 65 stops moving by stopping the rotation of the drive plate 69a. The position of the pressing piston 65 when the stroke of the pressing piston 65 ends is the pressing completion position of the pressing piston 65. At this time, the drive plate 69a, the facing 69b, the driven plate 69c, the retaining plate 69d, the snap ring 69e and the like are elastically deformed by the pressing force of the pressing piston 65 (particularly, the thickness of the facing 69b is reduced). Thus, the LR brake 60 is in the engaged state.

(Iv) When released-to zero clearance position When the engaged LR brake 60 is released, first, the pressing piston 65 is positioned at the pressing completion position, and the clearance adjusting piston 66 is positioned at the standby position. In this state, the hydraulic pressure in the A chamber 61 is discharged. As a result, the pressing force of the pressing piston 65 is removed. For example, as shown in FIG. 5, the friction plates (drive plate 69a, facing 69b, driven plate 69c, retaining plate 69d, and snap) that have been pressed up to that point are used. Only the pressing piston 65 is moved away from the friction plates 69a, 69c by the elastic restoring force of the ring 69e and the like.

  The pressing piston 65 is pushed back by the elastic restoring force to release the pressing of the friction plates 69a and 69c and stop. The position of the pressing piston 65 at this time is the position where the clearance is the smallest among the clearances in which no power is transmitted (that is, the position where the clearance is zero). That is, the position of the pressing piston 65 at this time is the zero clearance position of the pressing piston 65.

  This zero clearance position is a position determined by the structural state (for example, thickness and other dimensions) of the friction plate (including drive plate 69a, facing 69b, driven plate 69c, retaining plate 69d, snap ring 69e, etc.) Moreover, it reflects the current structural situation (thickness reduction due to wear, etc.). For example, if the friction plates 69a and 69c are new, the thickness decrease due to wear is small, so the distance by which the pressing piston 65 is pushed back becomes long, the zero clearance position is displaced to the engine side, and the friction plates 69a and 69c If it is old, the thickness is reduced due to wear, etc., so that the distance to which the pressing piston 65 is pushed back is shortened, and the zero clearance position is displaced to the non-engine side.

  The standby position of the pressing piston 65 before the L-R brake 60 is engaged and the zero clearance position after the engagement are not always the same. That is, each time the LR brake 60 is engaged, the zero clearance position is updated according to the current structural state of the friction plate, and the relative position of the pressing piston 65 with respect to the clearance adjusting piston 66 varies depending on the zero clearance position. To do. Therefore, the standby position of the pressing piston 65 before the L-R brake 60 is engaged and the zero clearance position after the engagement are often not the same.

(V) When released-to the initial position Next, the hydraulic pressure in the B chamber 62 is discharged with the pressing piston 65 positioned at the zero clearance position and the clearance adjusting piston 66 positioned at the standby position. As a result, for example, as shown in FIG. 4, the pressing piston 65 and the clearance adjusting piston 66 are both moved away from the friction plates 69a and 69c by the urging force of the return spring 164, and are positioned at their initial positions. As a result, the LR brake 60 is released.

  At this time, the return spring 164 acts only on the clearance adjusting piston 66 and does not act on the pressing piston 65. Therefore, the pressing piston 65 moves to the engine side together with the clearance adjustment piston 66 that moves to the engine side by the reaction force of the return spring 164 while maintaining the relative position to the clearance adjustment piston 66 without being disturbed. To do. That is, the pressing piston 65 and the clearance adjusting piston 66 return to the initial positions while the zero clearance position is recorded (that is, the memory effect).

  The initial position of the pressing piston 65 before engagement of the LR brake 60 and the initial position of the pressing piston 65 after engagement are not always the same. That is, each time the LR brake 60 is engaged, the zero clearance position is updated according to the current structural state of the friction plate, and the relative position of the pressing piston 65 with respect to the clearance adjusting piston 66 varies depending on the zero clearance position. To do. Therefore, in many cases, the initial position of the pressing piston 65 before fastening the LR brake 60 and the initial position of the pressing piston 65 after fastening do not match.

(Vi) At the time of re-engagement-to the standby position When the LR brake 60 is re-engaged in a state where the zero clearance position has been recorded, the pressing piston 65 and the clearance adjusting piston 66 are initially set in the same manner as described above. The hydraulic pressure is supplied to the B chamber 62 while being in the position. As a result, the pressing piston 65 and the clearance adjusting piston 66 move to the side opposite to the engine, the clearance adjusting piston 66 contacts the stopper member 160, and the pressing piston 65 and the clearance adjusting piston 66 stop. To do. At this time, the position of the pressing piston 65 and the position of the clearance adjustment piston 66 are the standby position of the pressing piston 65 and the standby position of the clearance adjustment piston 66, respectively, but the zero clearance position is recorded as described above. Therefore, the pressing piston 65 is automatically positioned at the zero clearance position.

  Thereafter, the operation of supplying hydraulic pressure to the A chamber 61 and fastening the LR brake 60 is the same as described above.

  Thus, since the LR brake 60 having this configuration has a two-stage piston structure and a two-stage stroke structure, the clearance adjusting piston 66 is stroked when there is a possibility that the LR brake 60 is fastened. Then, the zero clearance state is set, and when the LR brake 60 needs to be fastened, the pressing piston 65 is caused to stroke from the zero clearance state. For this reason, since the engagement response time of the LR brake 60 is a time required to stroke the pressing piston 65 in the zero clearance state to the engagement position, it can be engaged with good responsiveness. This makes it possible to fasten the LR brake 60 accurately at an appropriate timing, and to suppress a shift shock or the like caused by a shift in the fastening timing of the LR brake 60.

  As shown in FIG. 1, in this automatic transmission 1, an LR brake 60 that is engaged at the first forward speed is used in place of the conventionally used one-way clutch, and the LR brake is used. Since 60 has a large capacity, there is a problem that a shift shock generated when the engagement timing is shifted becomes larger. Therefore, as described above, the configuration that enables fastening from the zero clearance state and enhances the fastening response is effective in suppressing shift shock in the automatic transmission 1 of this configuration.

  Thus, in the LR brake 60 having the above-described configuration having the two-stage piston structure and the two-stage stroke structure, the shaft that sandwiches the opening of the A passage oil passage 63 that opens to the inner peripheral surface of the transmission case 3. Although the first outer peripheral seal member 681 that isolates the A chamber 61 and the B chamber 62 and the second outer peripheral seal member 683 that isolates the A chamber 61 and the transmission case 3 are located on both sides in the direction, Among these seal members, the first outer peripheral seal member 681 is attached to the first piston member 671, and the second outer peripheral seal member 683 is attached to the second piston member 672. The end of the transmission case 3 on the side opposite to the engine (not shown) is open. When the LR brake 60 is assembled to the transmission case 3, first, the first piston member 671 with the first outer peripheral seal member 681 is inserted into the transmission case 3 from the non-engine side toward the engine side. The first piston member 671 is assembled at a predetermined position. The concave groove 610 provided on the inner peripheral surface of the transmission case 3 fulfills the function of temporarily releasing the restraint of the first outer peripheral seal member 681 made of a lip seal while the first piston member 671 is being inserted. The taper 611 functions to guide the first outer peripheral seal member 681 to the inner peripheral surface of the transmission case 3. Thereby, the twist, the deformation | transformation, a failure | damage, etc. at the time of the 1st outer periphery sealing member 681 passing through this recessed groove 610 are suppressed. Further, since only the first outer peripheral seal member 681 is attached to the outer peripheral portion of the first piston member 671, the first piston member 671 is assembled while the first piston member 671 is being inserted. Later, the state of the first outer peripheral seal member 681 can be viewed in the axial direction from the non-engine side. This allows the first piston member 671 to be assembled accurately and reliably.

  Thus, after the first piston member 671 is assembled to the transmission case 3, the stopper member 160 made of a C-shaped snap ring is assembled at a predetermined position in the concave groove 610. Further, the locking member 162 is inserted into the A chamber oil passage 63.

  When the assembly of the stopper member 160 is completed, the second piston member 672 is inserted into the transmission case 3 from the non-engine side toward the engine side, and the second piston member 672 is assembled at a predetermined position. Since only the second outer peripheral seal member 683 is mounted on the outer peripheral portion of the second piston member 672, during the insertion of the second piston member 672 and after the second piston member 672 is assembled. The state of the second outer peripheral seal member 683 can be viewed in the axial direction from the non-engine side. The assembly of the second piston member 672 can also be performed accurately and reliably.

  In this way, the clearance adjustment piston 66 is divided into two piston members, the first piston member 671 and the second piston member 672, and a single seal member is attached to each piston member, whereby the transmission case 3 It is possible to improve the assemblability of the LR brake 60 having a configuration including two seal members that are in contact with each other in an axially aligned state with respect to the inner peripheral surface.

  Further, in the clearance adjustment piston 66 divided into two piston members, the first piston member 671 and the second piston member 672, an opening 612 of the A chamber 61 is provided at an intermediate position in the axial direction. The portion 674 is used as a receiving portion that comes into contact with the stopper member 160. In other words, a configuration for restricting the stroke amount of the first piston member 671 is provided at an intermediate position in the axial direction of the clearance adjustment piston 66 by utilizing a configuration necessary for supplying and discharging hydraulic pressure to and from the A chamber 61. The axial length of the LR brake 60 can be shortened.

  Further, as described above, the stopper member 160 is mounted in the concave groove 610 used for assembling the first piston member 671. This also reduces the axial length of the LR brake 60. In addition, by providing the A chamber oil passage 63 at a position overlapping the concave groove 610 in the axial direction, the axial length of the LR brake 60 can be further shortened.

  As described above, the stopper member 160 fixed in the recessed groove 610 has an inner peripheral end portion constituted by the opening edge portion 674 of the first piston member 671 and the outer peripheral portion of the second piston member 672. Although the first piston member 671 and the second piston member 672 are separated from each other, the first piston member 671, the stopper member 160, and the second piston member 672 are positioned in the opening 612 of the A chamber 61. Can be sequentially assembled to the transmission case 3. As a result, the first piston member 671 and the second piston member 672 can be arranged so as to be aligned in the axial direction with the stopper member 160 interposed therebetween.

Here, as shown in FIG. 8, in the configuration in which the clearance adjusting piston 66 is divided into two members, a first piston member 671 and a second piston member 672, the A chamber 61 and the transmission case 3 are separated. Among the seal members to be isolated, the second outer peripheral seal member 683 is attached to the outer peripheral portion of the second piston member 672 and is in contact with the inner peripheral surface of the transmission case 3, and the outer peripheral portion of the third piston member 673. In addition, the radial position of the third outer peripheral seal member 685 contacting the inner peripheral side of the second piston member 672 is different. Therefore, the second piston member 672, when the hydraulic pressure is supplied to _{P A} to A chamber 61 receives a force _{F outer} corresponding to the pressure receiving area corresponding to the difference between the positions of the two sealing members 683,685. This force F _outer is a direction toward the non-engine side as shown by a solid arrow in FIG. Accordingly, the second piston member 672 receives the reaction force F _spg of the return spring 164 (see the white arrow in FIG. 8) and the force F _outer corresponding to the pressure receiving area described above. more hydraulic _{P a} supplied into the 61 increases, since the greater the force _{F outer} direction towards the opposite side to the engine described above, the second piston member 672 against the reaction force _{F spg} of the return spring 164 counterclockwise As a result, it may move away from the first piston member 671. In the above configuration, the outer peripheral end portion of the pressing piston 65 (that is, the third piston member 673) fitted inside the clearance adjustment piston 66 is in contact with the second piston member 672 of the clearance adjustment piston 66. On the other hand, since the inner peripheral end of the third piston member 673 is in contact with the first piston member 671, the second piston member 672 is separated from the first piston member 671, and the second piston member 672 is separated. If the relative position between the first piston member 671 and the first piston member 671 changes, the stroke operation of the third piston member 673 is hindered.

Therefore, in the above configuration, the blocking member 684 is attached to the contact end portion 676 of the second piston member 672, thereby preventing the second piston member 672 from separating from the first piston member 671. Yes. That is, the blocking member 684 blocks the hydraulic oil from passing between the contact end portion 676 and the side wall 675 of the first piston member 671, so that the contact end portion 676 includes a chamber A. the hydraulic _{P a} which was fed into 61, the force _{F inner,} the direction toward the engine side will act. This force F _inner, the area of the abutting ends 676 (this area, as shown in FIG. 8, is proportional to the radial width) is set to a magnitude of the hydraulic pressure P _A in the A chamber 61, by Therefore, by setting the contact end portion 676 to an appropriate size, F _outer ≦ (F _spg + F _inner ) is maintained, and the second piston member 672 is separated from the first piston member 671. It becomes possible to prevent reliably. Thus, in the configuration in which the clearance adjusting piston 66 into which the pressing piston 65 is fitted is divided into the first piston member 671 and the second piston member 672, the first piston member 671 and the second piston member 672 are separated from each other. Is avoided. As a result, the stroke operation of the pressing piston 65 fitted in the clearance adjusting piston 66 is stabilized.

  Even when the second piston member 672 is temporarily separated from the first piston member 671 (for example, when the function of blocking the passage of hydraulic oil is reduced due to the deterioration of the blocking member 684 described above, etc.) The third outer peripheral seal member 685 has a guard portion 6851 as shown in FIGS. 8 and 9 in order to prevent the lip seal from being damaged and to ensure the oil tightness of the A chamber 61. The guard portion 6851 is provided adjacent to the inner peripheral side of the seal portion 6852 that contacts the second piston member 672 so as to protrude from the seal portion 6852 to the engine side. The third outer peripheral seal member 685 is axially opposed to the step portion between the outer peripheral portion and the intermediate portion of the second piston member 672, and as described above, the second piston member 672 is connected to the first piston member. When moving away from 671 and toward the opposite engine side, the stepped portion of the second piston member 672 contacts the guard portion 6851 as shown in FIG. This prevents the second piston member 672 from moving further to the non-engine side. As a result, the second piston member 672 is prevented from hitting the seal portion 6852 of the third outer peripheral seal member 685, and the seal portion 6852 is maintained in oil tightness while preventing the seal portion 6852 from being damaged. Yes.

  In the LR brake 60 having the above-described configuration, the A chamber 61 is a pressing hydraulic chamber, and the B chamber 62 is a clearance adjusting hydraulic chamber. Conversely, the A chamber 61 is a clearance adjusting hydraulic chamber, The B chamber 62 may be a pressing hydraulic chamber.

1 Automatic transmission (transmission)
160 Stopper member 162 Locking member 163 Locking member 164 Return spring 3 Transmission case 60 LR brake (brake device)
61 A chamber (pressing hydraulic chamber, second hydraulic chamber)
Room B (Clearing adjustment hydraulic chamber, 1st hydraulic chamber)
63 Oil passage 65 for chamber A Pressing piston (second piston)
66 Clearance adjustment piston (first piston)
69 Multi-plate brake 69a Friction plate 69c Friction plate 610 Concave groove 612 Opening portion 671 First piston member 672 Second piston member 673 Third piston member 674 Opening edge portion 675 Side wall 676 Abutting end portion 678 Retainer portion 681 First outer periphery seal Member (first seal member)
683 Second outer peripheral seal member (second seal member)
684 Blocking member 685 Third outer peripheral seal member (third seal member)

Claims (3)

A transmission brake device for fastening and releasing a multi-plate brake provided in a transmission case according to supply and discharge of hydraulic pressure,
A first piston inserted in the transmission case and configured to move in the axial direction so as to be close to the multi-plate brake in accordance with the supply of hydraulic pressure to the first hydraulic chamber; and
The first piston and the multi-plate brake are interposed between the first piston and the first hydraulic chamber so as to move together with the first piston in a direction approaching the multi-plate brake. The first piston is configured to move relative to the first piston in the direction approaching the multi-plate brake in accordance with the supply of the hydraulic pressure to the second hydraulic chamber partitioned from the first piston. 2 pistons,
With
An oil passage for supplying and discharging hydraulic pressure to and from the second hydraulic chamber is opened on the inner peripheral surface of the transmission case,
An opening for communicating the second hydraulic chamber and the oil passage is provided at an intermediate position in the axial direction of the first piston,
On the inner peripheral surface of the transmission case, when the first piston moves in a direction close to the multi-plate brake, the position of the first piston is brought into contact with the edge of the opening. A brake device for a transmission to which a restricting stopper member is attached. The brake device for a transmission according to claim 1,
The transmission case is recessed from its inner peripheral surface and has a groove extending in the circumferential direction.
The stopper member is fixed in the groove,
The oil passage is provided in a position overlapping with the concave groove in the axial direction, and is a brake device for a transmission that communicates with the concave groove. The transmission braking device according to claim 2,
The stopper member is a C-shaped snap ring that has a cut and is fitted in the concave groove,
By engaging each of the cut ends of the C-shaped snap ring, the cut portions of the C-shaped snap ring are connected to the communication portion between the oil passage and the concave groove, so that the oil passage and the concave groove are formed. The brake device of the transmission to which the latching member which maintains being located in a communicating part is attached.

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