CN105899846B - gear transmission - Google Patents

Abstract

In the gear transmission, the carrier is supported by the housing via bearings. Bearings have: inner ring, outer ring, multiple rollers and cages. The axis of rotation of the rollers is inclined with respect to the central axis of the bearing. The cage is used to maintain the spacing between adjacent rollers. In the gear transmission, the outer peripheral surface of the inner ring and the inner peripheral surface of the outer ring are not provided with ribs for restricting the movement of the rollers in the rotational axis direction. A protrusion protruding toward the bearing center axis is provided on the small diameter portion side of the cage. At least one of the carrier and the inner ring is provided with an abutment surface to be brought into contact with the protruding portion. In the gear transmission, the movement of the rollers in the direction of the rotation axis is restricted by the contact between the protruding portion and the contact surface.

Description

gear transmission

technical field

This application claims priority based on Japanese Patent Application No. 2014-000212 for which it applied on January 6, 2014. All the contents of the above request are incorporated into this specification by reference. This specification discloses a technique related to gear transmissions.

Background technique

There is known a gear transmission device in which a carrier rotates relative to a housing, and the carrier or the housing constitutes an output portion. In such a gear transmission, the carrier is supported by the housing via a bearing. Japanese Patent Laid-Open No. 2010-159774 discloses a gear transmission in which a cylindrical roller bearing is arranged between a housing and a carrier. In the following description, Japanese Patent Laid-Open No. 2010-159774 is referred to as Patent Document 1. The rotational axis of the roller (ころ) of the cylindrical roller bearing of Patent Document 1 is inclined with respect to the bearing center axis, and constitutes an angular contact roller bearing. The angular contact roller bearing of Patent Document 1 is not provided with ribs for restricting the movement of the rollers in the rotational axis direction on the outer peripheral surface of the inner ring and the inner peripheral surface of the outer ring.

SUMMARY OF THE INVENTION

Invention to solve problem

When the rotation axis of the roller is inclined with respect to the bearing center axis, a force for moving the roller outward in the direction of the rotation axis acts on the roller during driving of the gear transmission. In Patent Document 1, the movement of the rollers to the outside in the direction of the rotation axis is restricted by bringing the large-diameter side end of the cage into contact with the housing. When the rollers try to move outward, the outer periphery of the large-diameter side end of the cage comes into contact with the housing. Therefore, when the force applied to the rollers increases, the cage may slide relative to the housing, the large-diameter side of the cage is deformed radially inward, and the axial direction of the rollers cannot be restricted. movement. As a result, there may be a situation where the rollers come into contact with the housing, and the rollers and/or the housing wear out. Or, the cage is deformed, which may prevent the rollers from rotating smoothly. This specification discloses a technology that solves the above-mentioned problems and more reliably restricts the movement of the rollers in the axial direction.

solution to the problem

The technology disclosed in this specification relates to a gear transmission device in which a gear carrier is supported by a housing via a bearing. The bearing has: an inner ring provided on a gear carrier; an outer ring provided on a housing; a plurality of rollers arranged between the inner ring and the outer ring; and a cage for holding adjacent rollers sub-interval. The rollers have axes of rotation that are inclined relative to the central axis of the bearing. In the above bearing, the outer peripheral surface of the inner ring and the inner peripheral surface of the outer ring are not provided with ribs for restricting the movement of the rollers in the direction of the rotation axis of the rollers. In addition, a protruding portion protruding toward the bearing center axis is provided on the small diameter portion side of the cage. At least one of the carrier and the inner ring is provided with an abutment surface to be brought into contact with the protruding portion. In the gear transmission disclosed in this specification, the movement of the rollers in the direction of the rotation axis is restricted by the contact between the protruding portion and the contact surface.

According to the above-described gear transmission, when the force for moving the rollers outward in the direction of the rotation axis acts on the rollers, the protrusions provided on the small diameter portions of the cages come into contact with the carrier or the inner ring, thereby opposing the rollers. Child movement is restricted. That is, the movement of the cage is restricted by engaging the protruding portion with the carrier or the inner ring, and the movement of the rollers in the direction of the rotation axis is restricted. Since the inner diameter of the protruding portion is smaller than the outer diameter of the abutting surface, even if the force applied to the roller is large, the protruding portion does not come off the abutting surface. The above-described gear transmission can more reliably restrict the movement of the rollers in the direction of the rotation axis as compared with the conventional gear transmission.

In addition, "the inner ring is provided on the carrier" not only refers to the form in which the inner ring, which is a separate member from the carrier, is fixed to the carrier, but also includes that the carrier functions as the inner ring by processing the outer peripheral surface of the carrier. Shape. Similarly, "the outer ring is provided in the case" not only refers to the form in which the outer ring, which is a separate member from the case, is fixed to the case, but also includes the case in which the case serves as the outer ring by processing the inner peripheral surface of the case. functioning form.

Description of drawings

FIG. 1 is a cross-sectional view of a gear transmission according to a first embodiment.

FIG. 2 shows an enlarged cross-sectional view of the portion enclosed by the dotted line II in FIG. 1 .

FIG. 3 is an enlarged cross-sectional view of a part of the gear transmission according to the second embodiment.

FIG. 4 is a cross-sectional view of a gear transmission according to a third embodiment.

FIG. 5 is an enlarged cross-sectional view of the portion enclosed by the dotted line V in FIG. 4 .

FIG. 6 is an enlarged cross-sectional view of a part of the gear transmission of the fourth embodiment.

FIG. 7 is an enlarged cross-sectional view showing a part of the gear transmission of the fifth embodiment.

FIG. 8 is an enlarged cross-sectional view of a part of the gear transmission of the sixth embodiment.

FIG. 9 is an enlarged cross-sectional view showing a part of the gear transmission of the seventh embodiment.

FIG. 10 is an enlarged cross-sectional view of a part of the gear transmission of the eighth embodiment.

FIG. 11 is a cross-sectional view of a gear transmission according to a ninth embodiment.

FIG. 12 is an enlarged cross-sectional view of the portion enclosed by the broken line XII in FIG. 11 .

Detailed ways

Several technical features of the gear transmission disclosed in this specification will be described below. In addition, the matters described below each independently have technical practicality.

The gear transmission has a carrier and a housing. The carrier is rotatably supported by the housing via the first bearing. Preferably, a plurality of gears are accommodated in the housing. The gear transmission preferably also has a crankshaft, an eccentric rotating gear and an autorotating gear. It is preferable that the crankshaft is rotatably supported by the carrier. Preferably, the crankshaft has an eccentric body. Preferably, the eccentric rotating gear cooperates with the eccentric body of the crankshaft and rotates eccentrically with the rotation of the crankshaft. The self-rotating gear meshes with the eccentric rotating gear, and preferably has a different number of teeth from that of the eccentric rotating gear. The eccentric rotating gear is an external gear, and the self-rotating gear is preferably an internal gear. The internal teeth are provided on the inner peripheral surface of the casing, and the casing is preferably also used as the internal gear.

Preferably, the first bearing has an inner ring, an outer ring and a plurality of rollers. It is better to set the inner ring on the gear frame. In addition, the inner ring may be fixed to the outer peripheral surface of the carrier, and the outer peripheral surface of the carrier may function as the inner ring. The outer ring is preferably arranged on the casing. The outer ring may be fixed to the inner peripheral surface of the case, and the inner peripheral surface of the case may function as the outer ring. It is preferable to arrange multiple rollers between the inner ring and the outer ring.

It is preferable that the outer peripheral surface of the inner ring is not provided with a rib for restricting the movement of the rollers in the direction of the rotation axis. That is, it is preferable that the outer peripheral surface of the inner ring is not provided with a protruding portion contacting the end portion in the direction of the rotation axis of the roller. In addition, it is preferable that a rib for restricting the movement of the rollers in the direction of the rotation axis is not provided on the inner peripheral surface of the outer ring. That is, it is preferable that the inner peripheral surface of the outer ring is not provided with a protruding portion that contacts the end portion in the direction of the rotation axis of the roller.

It is preferable that the plurality of rollers have a rotation axis inclined with respect to the bearing center axis of the first bearing. The rollers may be cylindrical or conical. When the rollers are cylindrical, the first bearing is a cylindrical roller bearing (angular contact roller bearing). When the rollers are tapered, the first bearing is a tapered roller bearing. The rotation axis of the roller is preferably inclined so as to approach the bearing center axis of the first bearing as it goes toward the inner side of the gear transmission (the center side in the axial direction of the gear transmission). When the first bearing is a tapered roller bearing, it is preferable that the small-diameter portion of the roller is positioned more inward of the gear transmission than the large-diameter portion.

It is preferable that the first bearing has a cage for maintaining the interval between adjacent rollers. The cage is preferably annular, and preferably has a large diameter portion and a small diameter portion. It is preferable that the small diameter portion of the cage is positioned closer to the inner side of the gear transmission than the large diameter portion of the cage. A plurality of holes (grooves) are provided in the circumferential direction of the cage, and the rollers are preferably arranged in the holes. It is preferable to provide a protruding portion protruding toward the bearing center axis of the first bearing on the small diameter portion side of the cage. The protruding portion is preferably provided at the end portion on the side of the small diameter portion of the cage. It is preferable that the protruding part surrounds the central axis of the bearing. The diameter of the inner peripheral surface of the protruding portion is preferably the minimum value of the diameter of the cage.

Preferably, the contact surface to be brought into contact with the protruding portion is provided on the carrier. The contact surface may be provided on the inner ring. The contact surface may be provided on both the carrier and the inner ring. It is preferable that the contact surface is located on the outer side of the gear transmission (the end portion side in the axial direction of the gear transmission) than the protruding portion. It is preferable that the contact surface is located on the outer side of the gear transmission rather than the protruding portion. Preferably, the abutment surface surrounds the axis of the gear transmission. The contact surface is preferably provided so as to be orthogonal to the axial direction of the gear transmission. Preferably, the abutment surface is provided with a groove around the axis of the gear transmission. In addition, a rib may be provided in the protruding portion, and the rib may be inserted into the groove when the protruding portion abuts on the contact surface. The aforementioned ribs preferably extend along the axis of the gear transmission.

Example

(first embodiment)

The gear transmission 100 will be described with reference to FIG. 1 . In addition, in the following description, about the member which has substantially the same function, the code|symbol of the letter which attached|subjected the code|symbol may be abbreviate|omitted and demonstrated. The gear transmission 100 has an internal gear 60 , a carrier 2 , a crankshaft 10 and an external gear 28 . The internal gear 60 has a housing 59 and a plurality of internally toothed pins 58 . The case 59 surrounds the radially outer side of the external gear 28 . The inner tooth pin 58 has a cylindrical shape and is arranged on the inner peripheral surface of the housing 59 . The carrier 2 is rotatably supported by the casing 59 by a pair of first bearings 20 ( 20 a , 20 b ). The internally toothed pin 58 is arranged between the first bearings 20a and 20b. The first bearing 20 restricts movement of the carrier 2 relative to the housing 59 in the axial direction and the radial direction. A tapered roller bearing is used as the first bearing 20 in the gear transmission 100 .

The first bearing 20 a includes the inner ring 12 , the outer ring 16 , the rollers 14 , and the cage 18 . The inner ring 12 is integrated with the gear carrier 2 . More specifically, the outer peripheral surface of the carrier 2 also serves as the inner ring 12 . That is, the inner ring 12 is a part of the carrier 2 . The outer ring 16 is attached to the case 59 . The outer ring 16 is fitted into the inner peripheral surface of the case 59 . The first bearing 20a has a plurality of rollers 14 . A portion of the plurality of rollers 14 is shown in FIG. 1 .

The outer peripheral surface of the inner ring 12 and the inner peripheral surface of the outer ring 16 do not have protrusions protruding toward the rotation axis 25 . That is, the outer peripheral surface of the inner ring 12 and the inner peripheral surface of the outer ring 16 do not have ribs for restricting the movement of the rollers 14 in the direction of the rotation axis 25 . The space between the adjacent rollers 14 is maintained by the cage 18 . Specifically, a plurality of holes (not shown) are provided in the circumferential direction of the cage 18 , and the rollers 14 are arranged in the respective holes. The axis of rotation 25 of the rollers 14 is inclined relative to the axis 56 . The axis 56 is not only the rotation axis of the carrier 2 or the case 59 , but also the bearing center axis of the first bearing 20 .

The first bearing 20 b has an inner ring 42 , an outer ring 46 , rollers 44 , and a cage 48 . The inner ring 42 is integrated with the carrier 2 . The outer peripheral surface of the carrier 2 also serves as the inner ring 42 . That is, the inner ring 42 is a part of the carrier 2 . The outer ring 46 is attached to the case 59 . The outer ring 46 is fitted into the inner peripheral surface of the case 59 . The first bearing 20b has a plurality of rollers 44 .

The outer peripheral surface of the inner ring 42 and the inner peripheral surface of the outer ring 46 do not have protrusions protruding toward the rotation axis 35 . That is, the outer peripheral surface of the inner ring 42 and the inner peripheral surface of the outer ring 46 do not have ribs for restricting the movement of the rollers 44 in the direction of the rotation axis 35 . The space between the adjacent rollers 44 is maintained by the cage 48 . A plurality of holes (not shown) are provided in the circumferential direction of the cage 48 , and the rollers 44 are arranged in the respective holes. The axis of rotation 35 of the rollers 44 is inclined relative to the axis 56 . The axes of rotation 25 , 35 approach the axis 56 as they go towards the inside of the gear transmission 100 . The absolute value of the inclination angle of the rotation axis 25 relative to the axis 56 is equal to the absolute value of the inclination angle of the rotation axis 35 relative to the axis 56 . That is, the position where the rotation axis 25 and the rotation axis 35 intersect is the midpoint of the first bearing 20 a and the first bearing 20 b in the direction of the axis 56 .

The carrier 2 has a first plate 2a and a second plate 2c. The first plate 2a has a columnar portion 2b. The columnar portion 2b extends from the first plate 2a toward the second plate 2c and is fixed to the second plate 2c. The first plate 2a and the second plate 2c are detachable. An oil seal 22 is provided between the first plate 2 a and the case 59 . In addition, the gear transmission 100 has the through hole 4 along the axis 56 . That is, a through hole is provided in the center of the carrier 2 and the external gear 28 .

The crankshaft 10 is supported on the carrier 2 by a pair of second bearings 6 . The second bearing 6a is attached to the first plate 2a, and the second bearing 6b is attached to the second plate 2c. The pair of second bearings 6 restrict movement of the crankshaft 10 relative to the carrier 2 in the axial direction and the radial direction. In the gear transmission 100 , tapered roller bearings are used as the pair of second bearings 6 .

The crankshaft 10 has a shaft portion 8 (8a, 8b) and two eccentric bodies 34 (34a, 34b). The eccentric bodies 34a and 34b are provided between the shaft portions 8a and 8b. The second bearing 6 is fixed to the shaft portion 8 . Therefore, the eccentric body 34 may be arranged between the second bearings 6a and 6b. The eccentric orientations of the eccentric body 34a and the eccentric body 34b are symmetrical with respect to the rotation axis 54 of the crankshaft 10 . The eccentric body 34a cooperates with the external gear 28a by means of a cylindrical roller bearing 32a. The eccentric body 34b cooperates with the external gear 28b via the bearing 32b. The movement of the cylindrical roller bearing 32 in the axial direction (the direction of the rotation axis 54 ) is restricted by the second bearing 6 .

The shaft portion 8b is fixed to the input gear 52 . The input gear 52 is fixed to the shaft portion 8b outside the second bearings 6a, 6b. The torque of the motor (not shown) is transmitted to the input gear 52 . When the torque of the motor is transmitted to the input gear 52 , the crankshaft 10 rotates about the axis of rotation 54 . When the crankshaft 10 rotates, the eccentric body 34 rotates eccentrically about the axis of rotation 54 . With the eccentric rotation of the eccentric body 34 , the external gear 28 rotates eccentrically while meshing with the internal gear 60 . The external gear 28 rotates eccentrically about the axis 56 of the gear transmission 100 . The external gear 28a and the external gear 28b rotate eccentrically symmetrically with respect to the axis 56 . The number of teeth of the external gear 28 and the number of teeth of the internal gear 60 (the number of pins 58 with internal teeth) are different. The external gear 28 is supported by the carrier 2 via the crankshaft 10 . Therefore, when the external gear 28 rotates eccentrically, the carrier 2 rotates with respect to the internal gear 60 (housing 59 ) in accordance with the difference in the number of teeth between the external gear 28 and the internal gear 60 .

The first bearing 20 will be described in detail with reference to FIG. 2 . In addition, in the following description, the structure of the 1st bearing 20a is demonstrated. About the 1st bearing 20b, since the structure is substantially the same as that of the 1st bearing 20a, description is abbreviate|omitted.

As shown in FIG. 2 , the small diameter portion 18 a of the holder 18 is provided with a protruding portion 62 . The protrusions 62 protrude towards the axis 56 (see also FIG. 1 ). The protrusion 62 circles the axis 56 . The diameter of the circle formed by the inner peripheral surface of the protruding portion 62 is the smallest diameter among the circles formed by the inner peripheral surface of the cage 18 . In the direction of the axis 56 , the protrusion 62 is opposite to the carrier 2 . In addition, as described above, the outer peripheral surface of the carrier 2 also serves as the inner ring 12 . Therefore, the protruding portion 62 may be opposed to the inner ring 12 . A flat surface 64 is provided at a portion of the protruding portion 62 facing the carrier 2 . In addition, the flat surface 64 is orthogonal to the direction of the axis 56 . That is, the entire flat surface 64 is included in one plane orthogonal to the axis 56 .

The carrier 2 has a contact surface 66 at a portion facing the protruding portion 62 . The contact surface 66 is perpendicular to the direction of the axis 56 . That is, the entire contact surface 66 is included in one plane orthogonal to the axis 56 . When a force for moving the rollers 14 to the outside (the end side in the direction of the rotation axis 25 of the gear transmission 100 ) is applied to the rollers 14 , the rollers 14 move to the outside together with the cage 18 , and the protrusions 62 (flat The surface 64) is in contact with the contact surface 66. The carrier 2 has a restricting portion 65 radially inward of the protruding portion 62 . The restricting portion 65 restricts the inward movement of the cage 18 (the center side in the direction of the rotation axis 25 of the gear transmission), and restricts the inward movement of the rollers 14 .

The advantages of the gear transmission 100 are described. When the gear transmission 100 is driven, a force for moving the rollers 14 of the first bearing 20a toward the outside is applied to the rollers 14 . Similarly, the force which moves the roller 44 of the 1st bearing 20b toward the outer side of the rotation axis 35 direction is applied to the roller 44. As shown in FIG. The first bearing 20a and the first bearing 20b have the same advantages. Therefore, below, only the 1st bearing 20a is demonstrated. As described above, the inner ring 12 and the outer ring 16 do not have ribs that restrict the movement of the rollers 14 . Therefore, the inner ring 12 and the outer ring 16 do not come into contact with the ends of the rollers 14 on the large diameter portion side. Wear of the rollers 14 can be prevented.

The movement of the rollers 14 is restricted by the cage 18 . Therefore, when a force for moving the rollers 14 outward is applied to the rollers 14 , the rollers 14 tend to move outward together with the cage 18 . When the cage 18 is about to move outward, the protruding portion 62 of the cage 18 abuts against the contact surface 66 , and the movement of the rollers 14 is restricted. In the case of the gear transmission 100, the protruding portion 62 extends from the small diameter portion 18a of the holder 18 toward the inner side (the axis 56 side). Therefore, even if the force for moving the rollers 14 to the outside increases, the cage 18 is not deformed.

In the gear transmission 100 , after the protruding portion 62 abuts against the abutting surface 66 , as long as the protruding portion 62 and/or the abutting surface 66 are not damaged, the roller 14 can be continuously restricted from moving outward. On the other hand, as described above, in the conventional gear transmission, the outer movement of the rollers is restricted by bringing the large diameter portion of the cage into contact with the housing. Therefore, when the force for moving the rollers to the outside increases, the cage slides with respect to the housing, the large-diameter portion of the cage deforms inward, and the movement of the rollers cannot be restricted. Compared with the conventional gear transmission, the gear transmission 100 can restrict the movement of the rollers more reliably.

As can be seen from FIG. 1 , the large diameter portion of the holder 18 is not in contact with the housing 59 and the carrier 2 . Therefore, the gap between the housing 59 and the carrier 2 can be prevented from being blocked by the holder 18 . That is, the cage 18 is prevented from blocking the outer space 24 of the first bearing 20 (the space outside the first bearing 20 in the direction of the rotation axis 25 ) and the inner space 26 of the first bearing 20 (in the direction of the rotation axis 25 than the first bearing 20 ) 1 The space on the inner side of the bearing 20). The movement of lubricant and the like between the outer space 24 and the inner space 26 can be prevented from being restricted.

In addition, since the holder 18 does not come into contact with the casing 59, the casing 59 can be prevented from being worn. Moreover, compared with the conventional gear transmission, the gear transmission 100 does not need to provide the part which contacts the large diameter part of a cage in a housing (especially, refer to the 1st bearing 20b). Compared with the conventional gear transmission, the gear transmission 100 can be reduced in size and weight.

(Second embodiment)

The gear transmission 200 will be described with reference to FIG. 3 . The gear transmission 200 is a modification of the gear transmission 100 , and the same reference numerals or the same last two-digit reference numerals are assigned to the same members as the gear transmission 100 , and the description is omitted. The gear transmission 200 differs only in the structure around the first bearing 220 from the structure around the first bearing 20 of the gear transmission 100 . The other structures of the gear transmission 200 are substantially the same as those of the gear transmission 100 . 3 shows only a part of the gear transmission 200 (the part corresponding to FIG. 2 ).

The gear transmission 200 has the first bearing 220 . The first bearing 220 has the inner ring 212 , the outer ring 16 , the rollers 14 , and the cage 218 . The outer peripheral surface of the carrier 202 also serves as the inner ring 212 . The small diameter portion 218a of the retainer 218 is provided with a protruding portion 262 extending toward the axis line 56 (the bearing center axis of the first bearing 220, see also FIG. 1). Ribs 268 extending along axis 56 are provided on protrusion 262 . Rib 268 surrounds axis 56 . The rib 268 is provided in the end part on the axis line 56 side of the protrusion part 262 . The rib 268 forms a part of the inner peripheral surface of the small diameter part 218a.

The inner ring 212 (carrier 202 ) has an abutment surface 266 to abut against the flat surface 264 of the protruding portion 262 . The groove 270 is provided in a part of the contact surface 266 . The grooves 270 circle around the axis 56 . When the roller 14 is about to move outward, the flat surface 264 abuts against the abutting surface 266 , and the rib 268 is inserted into the groove 270 . Thereby, the movement of the roller 14 can be restrained more reliably.

(third embodiment)

The gear transmission 300 will be described with reference to FIGS. 4 and 5 . The gear transmission 300 is a modification of the gear transmission 100 , and the same reference numerals or the same last two digits are assigned to the same members as the gear transmission 100 , and the description is omitted. Unlike the gear transmission 100 , the inner ring 312 of the first bearing 320 of the gear transmission 300 is a member independent of the carrier 302 . In the following description, the 1st bearing 320a is demonstrated, and the description of the 1st bearing 320b is abbreviate|omitted.

The carrier 302 has a first plate 302a and a second plate 302c. The first plate 302a has a columnar portion 302b. The inner ring 312 is fitted into the outer circumference of the carrier 302 . The end portion of the inner ring 312 in the direction of the axis 56 is in contact with the carrier. Thereby, the inner ring 312 is positioned relative to the carrier 302 . The inner ring 312 is provided with an abutment surface 366 . When a force for moving the roller 14 to the outside is applied to the roller 14 , the protruding portion 62 (flat surface 364 ) comes into contact with the contact surface 366 . The gear transmission 300 can omit the inclined machining of the outer periphery of the carrier 302 .

(4th embodiment to 8th embodiment)

The gear transmission 400 of the fourth embodiment, the gear transmission 500 of the fifth embodiment, the gear transmission 600 of the sixth embodiment, the gear transmission 700 of the seventh embodiment, and the eighth embodiment will be described with reference to FIGS. 6 to 10 . Gearing 800 of an embodiment. The gear transmissions 400 to 800 are modified examples of the gear transmission 300 . With regard to the gear transmissions 400 to 800 , the same reference numerals or the same reference numerals with the same last two digits are attached to the same members as the gear transmission 300 , and descriptions thereof will be omitted. In the gear transmissions 400 to 800 , only the structure around the cage is different from the structure around the cage 318 of the gear transmission 300 . The other structures of the gear transmission devices 400 to 800 are substantially the same as those of the gear transmission device 300 . 6 to 10 show only a part of the gear transmissions 400 to 800 (the part corresponding to FIG. 5 ).

The gear transmission 400 has the first bearing 420 . The inner ring 312 , the outer ring 16 , and the rollers 14 are the same as the first bearing 320 (see FIG. 5 ). The shape of the cage 418 of the first bearing 420 is different from that of the first bearing 320 . The cage 418 is substantially the same as the cage 218 (see FIG. 3 ). That is, the rib 468 is provided in the protrusion part 462. As shown in FIG. The rib 468 is located on the axis 56 side (see also FIG. 4 ) rather than the inner peripheral surface of the inner ring 312 . In the gear transmission 400 , a groove 470 is provided in the carrier 402 . More specifically, a part of the carrier 402 located on the inner side in the radial direction of the inner ring 312 is cut out, and the groove 470 is formed by the cut-out part, the outer peripheral surface of the restricting portion 465 , and the inner peripheral surface of the inner ring 312 .

The gear transmission 500 has the first bearing 520 . The retainer 518 of the first bearing 520 is provided with a rib 568 on the protruding portion 562 similarly to the retainer 418 of the first bearing 420 . The protrusion length of the protrusion 562 toward the axis 56 is shorter than the protrusion length of the protrusion 462 of the cage 418 . In other words, the inner diameter of the protruding portion 562 is larger than the inner diameter of the protruding portion 462 . Compared with the first bearing 420, the first bearing 520 can reduce the size of the cage. Gear transmission 500 has slots 570 into which ribs 568 are inserted. The groove 570 is formed by the groove 567 provided in the inner ring 512 and the groove 569 provided in the carrier 502 . In other words, a portion of the inner peripheral surface of the inner ring 512 is cut off, and a portion of the outer peripheral surface of the carrier 502 corresponding to the cut-out portion is cut off, and the groove 570 is formed by both cut-out portions.

The gear transmission 600 has the first bearing 620 . The retainer 618 of the first bearing 620 is provided with a rib 668 on the protruding portion 662 similarly to the retainers 418 and 518 . The protrusion length of the protrusion 662 toward the axis 56 is shorter than the protrusion length of the protrusion 562 . That is, the inner diameter of the protruding portion 662 is also larger than the inner diameter of the protruding portion 562 . Compared with the first bearing 520, the first bearing 620 can reduce the size of the cage. Gearing 600 has slots 670 into which ribs 668 are inserted. The groove 670 is provided in the inner ring 612 . A part of the inner peripheral surface of the inner ring 612 is cut off, and the groove 670 is formed by the cut-out part, the outer peripheral surface of the carrier 302 (the restriction part 665 ), and the remaining part of the inner ring 612 .

The gear transmission 700 has the first bearing 720 . In the retainer 718 of the first bearing 720 , like the retainer 18 , no ribs are provided on the protruding portion 762 (see also FIGS. 2 and 5 ). The protrusion length of the protrusions 762 towards the axis 56 is longer than the protrusion length of the protrusions 62 . In the radial direction (direction orthogonal to the axis 56 ), the protruding portion 762 protrudes to a position closer to the axis 56 than the inner peripheral surface of the inner ring 712 . The inner diameter of the cage 718 of the protrusion 762 is smaller than the inner diameter of the inner ring 712 . In the gear transmission 700 , the carrier 702 is provided with a contact surface 766 . The contact surface 766 is the remaining portion after a portion of the outer peripheral surface of the carrier 702 is cut out to form the restricting portion 765 .

The gear transmission 800 has the first bearing 820 . In the retainer 818 of the first bearing 820 , similarly to the retainers 418 , 518 , and 618 , a rib 868 is provided on the protruding portion 862 . The protrusion length of the protrusions 862 toward the axis 56 is longer than the protrusion length of the protrusions 462 (see also FIG. 6 ). The protruding portion 862 protrudes to a position closer to the bearing center axis 56 than the inner peripheral surface of the inner ring 812 in the radial direction. The inner diameter of the cage 818 of the protrusion 862 is smaller than the inner diameter of the inner ring 812 . In the gear transmission 800 , the contact surface 866 and the groove 870 are provided in the carrier 802 . The abutting surface 866 is the remaining portion where the groove 870 is formed after a portion of the outer peripheral surface of the carrier 802 is cut out to form the restricting portion 865 .

(Ninth embodiment)

The gear transmission 900 will be described with reference to FIGS. 11 and 12 . The gear transmission 900 is a modification of the gear transmission 100 , and the same reference numerals or the same last two-digit reference numerals are assigned to the same members as the gear transmission 100 , and the description is omitted. The gear transmission 900 differs from the gear transmission 100 in that the first bearing 920 is formed as a cylindrical roller bearing (angular contact roller bearing). In addition, as described above, the first bearing 20 of the gear transmission 100 is a tapered roller bearing. In the following description, the 1st bearing 920a is demonstrated, and the description of the 1st bearing 920b is abbreviate|omitted.

The first bearing 920 has an inner ring 912 , an outer ring 916 , rollers 914 , and a cage 918 . The outer peripheral surface of the carrier 902 ( 902 a ) also serves as the inner ring 912 . The inclination angle of the outer peripheral surface of the inner ring 912 relative to the axis 56 is equal to the inclination angle of the inner peripheral surface of the outer ring 916 relative to the axis 56 .

As described above, in the first bearing 920 , the carrier 902 also serves as the inner ring 912 . However, the carrier may be independent of the inner ring like the first bearings 320 , 420 , 520 , 620 , 720 , and 820 . In addition, like the first bearings 220 , 420 , 520 , 620 , and 820 , ribs may be provided on the protruding portions. It is important that the rotation axis of the rollers of the first bearing is inclined with respect to the bearing center axis, the small diameter portion of the cage is provided with a protrusion protruding toward the bearing center axis, and the gear carrier and/or the inner ring are provided with An abutment surface on which the protruding portion abuts.

The specific examples of the present invention have been described in detail above, but these specific examples are merely illustrative and are not intended to limit the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. The technical features described in this specification or the drawings exhibit technical utility alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology illustrated in this specification or the drawings is used to simultaneously achieve a plurality of purposes, and the technology itself that achieves one of the purposes has technical utility.

Claims (4)

1. A gear transmission, the gear carrier of which is supported on a housing by means of bearings, wherein, The above bearing has: the inner ring, which is located on the gear carrier; an outer ring, which is located in the casing; a plurality of rollers disposed between the inner ring and the outer ring and having an axis of rotation inclined with respect to the central axis of the bearing; and cage, which is used to maintain the spacing of adjacent rollers, The outer peripheral surface of the inner ring and the inner peripheral surface of the outer ring are not provided with ribs for restricting the movement of the rollers in the direction of the above-mentioned rotation axis, A protruding portion protruding toward the center axis of the bearing is provided on the side of the small diameter portion of the cage, At least one of the carrier and the inner ring is provided with an abutment surface to be brought into contact with the protruding portion, The movement of the roller in the direction of the rotation axis is restricted by the contact of the protruding portion with the contact surface, The protruding portion is not in contact with the housing, The diameter of the inner peripheral surface of the protruding portion is the minimum value of the diameter of the cage. 2. The gear transmission of claim 1, wherein: A groove is provided on the abutting surface, Ribs are provided on the above-mentioned protrusions, The rib is inserted into the groove when the protruding portion is in contact with the abutting surface. 3. A gear transmission according to claim 1 or 2, wherein, The above bearing is a tapered roller bearing. 4. A gear transmission according to claim 1 or 2, wherein, The above bearing is a cylindrical roller bearing.

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