JPS63186059A - Transmission control device of automatic transmission with constant velocity running device - Google Patents

Abstract

PURPOSE:To reduce the transmission shock, by controlling the connecting condition of friction connecting elements for engine brake responding to the shift down condition whether it is in the acceleration or in the deceleration, in a shift down operation in a constant speed running. CONSTITUTION:The feeding and exhausting of the operation oil to hydraulic actuators 41a to 46a to operate friction connecting elements are carried out by an oil pressure circuit 60. The oil pressure circuit 60 furnishes a manual valve 64 and shift valves 71 to 73, while the first to the third control lines 106 to 108 branched from a main line 100 furnish the first to the third solenoid valves 76 to 78 respectively, and these valves are turned ON or OFF responding to a shift stage to set, by signals A, B, and C from a control circuit 200 respectively. Therefore, when the shift down signal G is output from a constant speed running device 203, the signal G is decided whether it is for an acceleration or for a deceleration, and the solenoid valves 76 to 78 are operated.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an automatic transmission, particularly an automatic transmission configured to obtain a plurality of gears by combining the operating positions of a plurality of shift valves.
The present invention also relates to a shift control device for an automatic transmission equipped with a constant speed traveling device that maintains a vehicle speed at a set vehicle speed.

(Prior art) Automatic transmissions installed in automobiles combine a torque converter and a speed change gear mechanism, and selectively connect the power transmission path of the speed change gear mechanism to multiple friction engagement elements such as clutches and brakes. It is configured to be switched by operation to automatically shift to a predetermined gear (see, for example, Japanese Patent Laid-Open No. 183160/1983).

On the other hand, automobiles equipped with this type of automatic transmission are sometimes equipped with a constant-speed traveling device that maintains a set vehicle speed on the roadway. This constant speed traveling device automatically controls the opening and closing of the engine throttle valve rev using an actuator according to the difference between the vehicle speed set by the driver and the actual vehicle speed, thereby changing the actual vehicle speed to the set vehicle speed. However, with this constant speed traveling device, there are cases where it is not possible to converge the vehicle speed to the set vehicle speed simply by controlling the throttle opening, and in such cases, the constant speed traveling device automatically A signal is output to the transmission control device to automatically shift the gear to a gear position suitable for the set vehicle speed (see, for example, Japanese Patent Laid-Open No. 117010/1983).

(Problems to be Solved by the Invention) Incidentally, automatic transmissions have a problem of so-called shift shock when shifting. In order to reduce this shift shock, it is effective to delay the engagement of the friction engagement element for engine braking that is engaged in the next gear after the friction engagement element that was engaged in the previous gear begins to release. However, if this is done, when the gear shift is a downshift when the engine brake is activated at a particularly high vehicle speed, the so-called "downshift" occurs between the time when the gear shift to the lower gear is delayed and the engine brake starts to operate. This results in poor dry running, which causes discomfort to the occupants.

To solve this problem, when downshifting at a vehicle speed above a predetermined speed, the engine brake friction engagement element is engaged from a high gear, and then the engine brake is engaged, and then the gear is switched to a low gear. By not passing through such a state during a downshift, the shift shock can be effectively reduced in low vehicle speed ranges where engine braking is not particularly required, and at the same time, in high vehicle speed ranges, the engine brake can be activated quickly during the shift. Conceivable. but,
In this case, the following problems occur in an automatic transmission equipped with a constant speed traveling device.

In other words, when driving at a constant speed and increasing the throttle opening to a predetermined limit in order to cope with a drop in vehicle speed, and then downshifting the transmission, this downshifting is for acceleration. Nevertheless, if the speed of the vehicle at that time is higher than the predetermined vehicle speed, the friction engagement element for engine braking operation will be engaged during gear shifting, and therefore the friction engagement element will be engaged at the beginning of the shift during acceleration. When the elements are engaged, a large shift shock occurs.9 The present invention is intended to deal with the above-mentioned problems in automatic transmissions. By appropriately controlling the friction engagement element for engine braking during a downshift, when this downshift occurs when accelerating, such as when climbing a hill, unnecessary early activation of the engine brake can be avoided and the gear can be shifted. To reduce the shock, and when the above-mentioned downshift involves decelerating when exiting the plane, the engine brake is activated early to prevent dry running, thereby ensuring good gear shifting in both cases. The purpose is to make it possible to obtain.

(Means for Solving the Problems) That is, the speed change control device for an automatic transmission equipped with a constant speed traveling device according to the present invention provides a speed change control device for an automatic transmission that is equipped with a constant speed traveling device. In a device that is equipped with a plurality of shift valves for supplying and discharging hydraulic oil, and is configured to obtain a plurality of gears by combining the operating positions of these shift valves, engine braking is performed from a predetermined high gear from the constant speed traveling device. an acceleration/deceleration determination means for determining whether the downshift is for acceleration or deceleration when outputting a downshift signal to a predetermined low gear where From there, the engine brake friction engagement element is not engaged, and then the gear is switched to a low gear, and when downshifting during deceleration, the engine brake friction engagement element is engaged from the high gear, and then the gear is shifted to a low gear. and control means for switching between stages.

(Function) According to the above configuration, when the transmission is downshifted to accelerate the vehicle speed to the set vehicle speed, such as when driving at a constant speed, the friction engagement element for engine braking is activated from a high gear. Since the gear is switched to a low gear through a state in which it is not engaged, it is possible to prevent a large shift shock from occurring due to engagement of the frictional engagement element at the beginning of a shift during acceleration. In addition, when the transmission is downshifted to reduce the vehicle speed to the set vehicle speed, such as when exiting the vehicle while driving at a constant speed, the transmission is shifted down from a high gear to a state in which the engine brake friction engagement element is engaged. Since the gear position pattern is changed, the friction engagement element is engaged at the beginning of the gear shift, and the engine brake is quickly activated, thereby avoiding the idle running state of the vehicle.

(Example) Examples of the present invention will be described below.

First, the mechanical configuration of the automatic transmission according to this embodiment will be explained with reference to FIG. 1. The automatic transmission 10 includes a torque converter 20 and a
It includes a speed change gear mechanism 30 driven by an output of zero, a plurality of friction engagement elements 41 to 46 such as clutches and brakes, and one-way clutches 51 and 52 that change the power transmission path of the mechanism 30, and these act as a driving range. Nori, 2,1. Each range of R and 1st to 4th speed in D range,
1st to 3rd speeds in 2 ranges and 1st to 2nd speeds in lunge are available.

The torque converter 20 includes a pump 22 fixedly installed in a case 21 connected to the engine output shaft 1, and a turbine 23 disposed opposite to the pump 22 and driven by the pump 22 via hydraulic oil. , a stator 25 that is interposed between the pump 22 and the turbine 23 and supported by the transmission case 11 via the one-way clutch 24 to increase torque; and the case 21 and the turbine 2
3, and a lock-up clutch 26 that directly connects the engine output shaft 1 and the turbine 23 via the case 21. Then, the turbine 23
The rotation is outputted to the speed change gear mechanism 30 side via the turbine shaft 27. Here, a pump shaft 12 passing through a turbine shaft 27 is connected to the engine output shaft 1, and the shaft 12 drives an oil pump 13 provided at the rear end of the transmission.

On the other hand, the speed change gear mechanism 30 is composed of a Ravigneau type planetary gear device, and includes a small sun gear 31 with a small diameter loosely fitted on the turbine shaft 27, and a small sun gear 31 that is loosely fitted onto the turbine shaft 27.
1, a large diameter large sun gear 32 loosely fitted on the turbine shaft 27, a plurality of short pinion gears 33 meshed with the small sun gear 31, and a front half meshed with the short pinion gear 33. It is composed of a long pinion gear 34 whose rear half meshes with the large sun gear 32, a carrier 35 that rotatably supports the long pinion gear 34 and the short pinion gear 33, and a ring gear 36 which meshes with the front half of the long pinion gear 34. has been done.

A forward clutch 41 and a first one-way clutch 51 are interposed in series between the turbine shaft 27 and the small sun gear 31, and a coast clutch 42 is interposed in parallel with these clutches 41 and 51. Additionally, a 3-4 clutch 43 is interposed between the turbine shaft 27 and the carrier 35, and a reverse clutch 44 is further interposed between the turbine shaft 27 and the large sun gear 32. Further, a 2-4 brake 45 made of a band brake for fixing the large sun gear 32 is provided between the large sun gear 32 and the reverse clutch 44, and a 2-4 brake 45 is provided between the carrier 35 and the transmission case 11. , a second one-way clutch 52 that receives and receives the reaction force of the carrier 35, and the carrier 35.
A low reverse brake 46 for fixing the is provided in parallel. The ring gear 36 is connected to the output gear 14.
The rotation of the output gear 14 is transmitted to left and right wheels (not shown) via a differential gear.

Next, the frictional engagement elements 41 such as the above-mentioned clutches and brakes
46 and the one-way clutches 51, 52 and the gear positions. First, in the first gear, the forward clutch 41 is engaged and the one-way clutches 51 and 52 are engaged. The second one-way clutches 51 and 52 become locked. Therefore, the output rotation of the torque converter 20 is input from the turbine shaft 27 to the small sun gear 31 of the planetary gear device 30 via the forward clutch 41 and the first one-way clutch 51. In this case, since the carrier 35 is fixed by the action of the second one-way clutch 52, the planetary gear device 30 operates in a differential manner to transmit rotation from the small sun gear 31 to the ring gear 36 via the short pinion gear 33 and the long pinion gear 34. It operates as a fixed gear train that does not perform As a result, a first speed state with a large reduction ratio corresponding to the ratio of the diameters of the small sun gear 31 and the ring gear 36 is obtained.

Next, in 2nd gear, in addition to the above 1st gear state, 2-
The four-brake 45 is activated, the large sun gear 32 in the planetary gear device 30 is fixed, and the second one-way clutch 52 is idled. Therefore, the rotation transmitted from the turbine shaft 27 to the small sun gear 31 is transmitted to the long pinion gear 34 via the short pinion gear 33, and the large sun gear 32 meshing with the long pinion gear 34 is fixed. It revolves on the large sun gear 32, and the carrier 35 rotates accordingly. As a result, the rotation of the carrier 35 (long pinion gear 3
The rotation of the ring gear 36 is increased by the amount of revolution of 1
As soon as the 2nd speed state, in which the reduction ratio is smaller than the 3rd speed state, is obtained, the 2-4 brake 45 is released from the 2nd speed state, and the 3-4 clutch 43 is engaged. Therefore, the rotation of the turbine shaft 27 is input to the small sun gear 31 via the forward clutch 41 and the first one-way clutch 51, and at the same time is input to the carrier 35 via the 3-4 clutch 43. . As a result, a third speed state is obtained in which the entire planetary gear device 30 rotates integrally and the ring gear 36 rotates at the same speed as the turbine shaft 27.

In addition, in 4th gear, the 2nd gear that was once released in 3rd gear is
-4 Brake 45 is re-engaged. Therefore, the rotation of the turbine shaft 27 is input from the 3-4 clutch 43 to the carrier 35 of the planetary gear device 30, causing the long pinion gear 34 to revolve.
Since it is fixed by the -4 brake 45, the long pinion gear 34 rotates while revolving together with the carrier 35. As a result, the long pinion gear 34
The ring gear 36 that meshes with the carrier 35 (rotation of the turbine shaft 27) is rotated at an increased speed by the rotation of the long pinion gear 34, thereby obtaining a fourth speed in an overdrive state. In this case, although the forward clutch 41 is in the engaged state, the first one-way clutch 51 in series with it is idle, so the rotation of the turbine shaft 27 is not input to the small sun gear 31.

Further, in reverse speed, the reverse clutch 44 and the low reverse brake 46 are engaged, and the rotation of the turbine shaft 27 is input to the large sun gear 32 of the planetary gear device 30, and the carrier 3 of the gear device 30 is inputted.
5 is fixed. Therefore, rotation is transmitted through a fixed gear train from the large sun gear 32 to the ring gear 36 via the long pinion gear 34, and the reduction ratio corresponds to the ratio of the diameters of the large sun gear 34 and the ring gear 36. is obtained, but in that case, the ring gear 36
The direction of rotation is opposite to the direction of rotation of the turbine shaft 27 or large sun gear 32.

Note that the first one-way clutch 51, which transmits rotation in 1st to 3rd gears, and the second one-way clutch 52, which receives no reaction force in 1st gear, idle during coasting, so the engine brake does not operate in these gears. However, in the 3rd gear of the D range, the 2nd and 3rd gears of the 2nd range, and the 1.2nd gear of the lunge, the coast clutch 42 parallel to the first one-way clutch 51 is engaged, and in the 1st gear of the range Since the low reverse brake 46 is engaged in parallel with the 2 one-way clutch 52, engine braking is obtained in the 3rd gear of the D range, the 2nd and 3rd gears of the 2nd range, and the 1st and 2nd gears of the lunge.

To summarize the relationship between the operation of each of the hydraulic engagement elements 41 to 46 and the one-way clutch 51, 52 and the gear position, the first
As shown in the table.

(Hereinafter, blank spaces) Next, referring to FIG. 2, a description will be given of the hydraulic circuit 60 that supplies and discharges hydraulic oil to the hydraulic actuators 41a to 46a that actuate the frictional engagement elements 41 to 46, respectively. Here, among the hydraulic actuators 41a to 46a, the hydraulic actuator 45a of the 2-4 brake 45 is composed of a servo piston having an apply boat 45a' and a release boat 45a''.
2-4 brake 4 when hydraulic oil is supplied only to
5 and when both boats 45a'45a'' are not supplied with hydraulic oil, and both boats 45a',
45a'' is configured to release the 2-4 brake 45 when hydraulic oil is supplied.Other actuators 41a to 44a and 46a are constituted by ordinary hydraulic pistons, and are configured to release the 2-4 brake 45 when hydraulic oil is supplied. The frictional engagement element is engaged when the friction engagement element is engaged.

This hydraulic circuit 60 first includes a regulator valve 61 that adjusts the pressure of hydraulic oil discharged from the oil pump 13 shown in FIG. 1 to the main line 100 to a predetermined line pressure.
and a throttle valve 62 that generates a throttle pressure according to the throttle opening of the engine.

This throttle pressure is further adjusted by the throttle modulator valve 63 and then supplied to the regulator valve 61, so that the line pressure is set to a value corresponding to the engine accelerator opening. It has become.

The hydraulic circuit 60 also includes a manual valve 64 that selectively sends the line pressure to each hydraulic line according to the selected range, and a manual valve 64 that operates according to the gear position to transfer the line pressure to each of the hydraulic actuators 41a to 41a. 46a are provided with shift valves 71, 72, and 73 of 1-2, 2-3, and 3-4 that selectively supply the fuel to the valve 46a.

The manual valve 64 has an input port f into which line pressure is introduced from the main line 100, and first to fifth output boats a to e, and by movement of the spool 64a,
In the D range, the input port f is the first. For the second output ports a and b, for the second range, the first output port. Second. 3rd output boats a, b, c, and 1st output boat in Lunge. Third. It is connected to the fourth output ports a, c, and d, and in the R range, to the fifth output port e. Each of the output boats a to e has first to fifth output lines 101 to 105, respectively.
is connected.

In addition, the above 1-2.2-3.3-4 shift valve 71,
72 and 73, the spools 71a, 72a, 73a are biased to the right side in the drawing by springs, and the control boats 71b, 72b, 73 are placed on the right side of these spools.
This is a configuration in which b is provided. And 1-2 shift valve 7
The first control line 106 branched from the main line 100 is connected to the control boat 71b of 1, and the first control line 106 is branched from the first output line 101 to the control boats 72b and 73b of the 2-3.3-4 shift valves 72.73. The second Third control lines 107 and 108 are connected to each other, and
These control lines 106, 107, and 108 are connected to the first and second lines, respectively. Second. A third solenoid valve 76,77,78 is provided. These solenoid valves 76-78
is the control boat 7 of the shift valve when each is OFF.
By introducing control pressure into 1b to 73b, the spool 71a
~73a is located on the left side in the drawing, and when the control boat is turned on, the control pressure in the control boats 71b~73b is drained, and the spools 71a~73a are positioned on the right side.9 Here, These solenoid valves 76 to 78 are operated according to the gear stage to be set by signals A, B, and C from a control circuit 200 that receives the vehicle speed and engine throttle opening from sensors 201 and 202, respectively. te ON
, OFF, but the solenoid valves 76 to 78 at each gear in the driving range are turned ON and OFF.
The FF combination patterns are basically set as shown in Table 2.

On the other hand, the first to fifth output lines 101 to 10 connected to each output port a to e in the manual valve 64
5, main line 1 in each forward range of D, 2.1
The first output line 101 connected to the first output line 101 is led to the actuator 41a of the forward clutch 41 via the one-way orifice 80. Therefore, above, 2
．． During lunge, the forward clutch 41 is always engaged. Note that the first output line 101 is provided with an N-D accumulator 81 for buffering when the forward clutch is engaged.

Further, a line 111 is branched from this first output line 101 and led to the 1-2 shift valve 71, and this branch line 111 is connected to the spool 71a when the first solenoid valve 76 is turned on. When it moves to the right, it is communicated via the one-way orifice 82 with the servo apply line 112 that reaches the apply boat 45a' of the servo piston 45a. Therefore, D.

2. When the first solenoid valve 76 is ON in lunge, that is, 2.3.4 speed in D range, 2nd and 3rd speed in 2nd range, and 2nd speed in lunge, the servo apply pressure is applied to the apply boat 45a'. will be introduced. Furthermore, the servo apply line 112 is also equipped with a 1-2 accumulator 8 for use as a buffer when the servo piston (2-4 brake) is connected.
3 are provided.

Further, the second output line 102 communicating with the main line 100 in the D and 2 ranges is led to a 2-3 shift valve 72. When the second solenoid valve 77 is OFF and the spool 72a is located on the left side, the line 102 is communicated with the 3-4 clutch line 113 that leads to the actuator 43a of the 3-4 clutch 43 through the one-way orifice 84. Therefore, when the second solenoid valve 77 is OFF in the D and 2 ranges, that is, the 3-4 clutch 43 is engaged in the 3.4 speed of the D range and the 3rd speed of the 2 range. The 3-4 clutch line 113 is provided with a bypass valve 85 and a 2-3 timing valve 86 in parallel with the one-way orifice 84 to adjust the engagement timing of the 3-4 clutch 43. , the 3-4 clutch line 113
A 2-3 accumulator 87 is also provided for buffering when the 3-4 clutch is engaged.

Further, a line 114 branched from the 3-4 clutch line 113 and a line 115 branched from the first output line 101 are led to the 3-4 shift valve 73. When the third solenoid valve 78 is OFF and the spool 73a is located on the left side, a line 114 branched from the 3-4 clutch line 113 connects to the release port 45a'' of the servo piston 45a via the one-way orifice 88. release line 116
In addition, line 1 branched from the first output line 101
15 are respectively connected to a coast clutch line 117 that reaches an actuator 42a of a coast clutch 42 via eight one-way orifices. Therefore, when both the 2nd and 3rd solenoid valves 77 and 78 are OFF in the D and 2 ranges, that is, in the 3rd speed of the D range and the 3rd speed of the 2nd range, servo release pressure is applied to the release port 45a'' of the servo piston 45a. The 2-4 brake 45 is released, and the third solenoid valve 7 is also released at the 2. lunge.
8 is OFF, that is, 3rd gear in D range, 2nd gear in 2nd range.
The coast clutch 42 is engaged in the third speed and the first and second lunge speeds.

Here, between the 3-4 clutch line 113 and the line 114 branched from the line 113, the 3-4 clutch pressure and servo release pressure are discharged via branch lines 118 and 119, respectively. Adjust 3
-2 timing valve 90 and 3-2 capacity valve 91 are provided. Further, the coast clutch line 117 is provided with a bypass line 120 that bypasses the one-way orifice 89.
A 3-4 capacity valve 92 is provided for opening and closing. This valve 92 is activated when the 3-4 clutch pressure is generated and when the manual valve 64 is
3rd output line 10 selected for range or lunge
3 is connected to the main line 100, the bypass line 120 is opened to adjust the discharge timing of the coast clutch pressure. Note that the line 121 branched from the third output line 103 is led to the pressure increasing side of the regulator valve 61 via the throttle backup valve 93, so that the line pressure is increased in the second range and lunge.

Further, the fourth output line 104 , which is connected to the main line 100 via the manual valve 64 , is led to the 1-2 shift valve 71 via the low-resolution use valve 94 and the line 122 . And the line 12
2, when the first solenoid valve 76 is OFF, the spool 7
When 1a is located on the left side, one-way orifice 95
The low reverse brake line 123 is connected to the actuator 46a of the low reverse brake 46 via the shuttle valve 96. Therefore, when the first solenoid valve 76 is off during lunge, that is, when the lunge is in first gear, the low reverse brake 46 is engaged.

Further, a fifth output line 105 that communicates with the main line 100 in the R range communicates with the low reverse brake line 123 via the one-way orifice 97 and the shuttle valve 96, and also communicates with the fifth output line 100.
A reverse clutch line 124 is branched from the reverse clutch line 5 through a one-way orifice 98 to an actuator 44a of the reverse clutch 44. Therefore, in the R range, the low reverse brake 46 and reverse clutch 44 are always engaged. In addition, the reverse clutch line 124 also has an N-R line for M thrust when the reverse clutch is engaged.
An accumulator 99 is provided. In addition, the fifth
A line 125 branched from the output line 105 is led to the pressure increasing side of the regulator valve 61 to increase the line pressure in the R range.

In addition to the above configuration, this hydraulic circuit 60 is equipped with a lock-up valve 150 for operating the lock-up clutch 26 in the torque converter 20 shown in FIG. A torque converter line 151 is led from a regulator valve 61 to this valve 150, and a main line 100 is connected as a control line 152 to a control line 150b at one end. When the lock-up solenoid valve 153 provided in the control line 152 is turned ON by a signal from the control circuit 200, the control boat 150b
By draining the control pressure in the torque converter line 151 and positioning the spool 150a on the right side, the torque converter line 151
is connected to a line 154 leading into the torque converter 20, thereby increasing the internal pressure of the torque converter 20 and engaging the lock-up clutch 26. Also, the solenoid valve 153 is turned OFF and the control boat 1
By introducing control pressure into the spool 15
When 0a moves to the left, the torque converter line 151 communicates with the lockup release line 155, lockup release pressure is introduced into the torque converter 20, and the lockup clutch 26 is released.

As described above, the signals A, B, and C from the control circuit 200 cause the first to third solenoid valves 76, 77, and 78 to switch to the second
It is turned on and off according to the combination pattern shown in the table, and
Each shift valve 71, 72.7 corresponding to this pattern
Each of the frictional engagement elements 41 to 46 is selectively engaged according to the positions of the spools 71a, 72a, and 73a of No. 3 and the select position of the manual valve 64, and the gear stage in each range is set as shown in Table 1. be done.

However, during the 4-3 downshift in the D range, the control circuit 200 controls the solenoid valves 76 to 78 (
7) The ON/OFF pattern is switched from the 4th speed pattern shown in Table 2 to the 3rd speed pattern via an intermediate pattern.

As shown in Table 3, this intermediate pattern is 1. In addition to the second intermediate pattern being set, this control circuit 2.00 receives signals E and F from sensors 201 and 202 indicating the vehicle speed and throttle opening, respectively, as shown in FIG. Inputting the downshift signal G from the constant speed traveling device 203 and the signal H from the idle switch 204 that detects whether the throttle opening is fully closed,
4-3 At the time of downshifting, based on these signals, the vehicle speed is set to a predetermined speed (for example, 40 km/h) V (1 or more), and the downshift signal G from the constant speed traveling device 203 is determined.
At the time of output, the above-mentioned 1. depends on whether the downshift is for acceleration or deceleration. One of the second intermediate patterns is selected. In this embodiment, as shown in parentheses in Table 3, a second pattern is set in which the first solenoid valve 76 is turned off in the third gear after the 4-3 shift, and the set vehicle speed Vo' (for example, 40
This second pattern is adopted in the third gear below (km/h).

(Hereinafter, blank space) Table 3 Next, the gear shifting operation during 4-3 gear shifting, which is a characteristic part of the present invention, will be explained according to the flowchart of FIG. 3 showing the operation of the control circuit 200.

First, the control circuit 200 reads the vehicle speed (or the rotational speed of the turbine shaft 27, which can be converted to the vehicle speed using the gear ratio of the current gear position) and the throttle opening in step S1, and then reads the throttle opening in step S2. In step S3, it is determined whether the current gear position is 4th gear or not, and if the gear position is other than 4th gear, normal gear change control is performed in step S3.

On the other hand, if the current gear position is 4th gear, the control circuit 2
00, it is determined in step S4 whether it is time to downshift to third gear based on each of the input signals E to H. If it is time to downshift, the actual vehicle speed is compared with the preset predetermined vehicle speed in step S.
Predetermined vehicle speed■.

If the vehicle speed is lower than s6, that is, when the vehicle speed is low and does not require engine braking, step s6. During a predetermined time T, control signals A to C are outputted to the first to third solenoid valves 76 to 78 so as to form the first intermediate pattern shown in Table 3 at step S. I). Further, at a high vehicle speed of 70 or more, the control circuit 200 performs the steps S,
Then, step S8 is executed to determine whether the downshift operation is caused by the downshift signal G from the constant speed traveling device 203. If the downshift is not due to this signal G but during normal driving, the first to third solenoid valves 76 to 78 are switched to the third solenoid valve for a predetermined time T in step S9+310.
control signals A-C to obtain the second intermediate pattern shown in the table.
is output (area ■ in Figure 4).

On the other hand, if the shift down operation is based on the shift down signal G from the constant speed traveling device 203 during constant speed traveling, the control circuit 200 executes steps S8 to Stt above to turn the idle switch 204 on. It is determined whether the throttle opening is fully closed or not based on the signal H from. If it is not fully closed, in other words, the downshift during constant speed driving causes the vehicle speed to exceed a certain allowable limit compared to the set vehicle speed, even though the throttle opening has been increased to a predetermined limit such as when climbing a hill. If the downshift is for acceleration, the control circuit 200 performs step S6. S7 is executed to output control signals A to C for a predetermined time T so that the patterns of the solenoid valves 76 to 78 become the first intermediate pattern. In addition, if it is determined in step Sll that the throttle opening is fully closed, that is, the downshift during this constant speed drift causes the vehicle speed to change even though the throttle opening is fully closed when exiting the vehicle. If the downshift is for deceleration because the vehicle speed has increased beyond a certain allowable limit, the control circuit 200 executes step S 9 + 310 and closes the solenoid valve 76 for a predetermined period of time T. Control signals A to C are outputted so that patterns .about.78 become second intermediate patterns.

Thereafter, the control circuit 200 executes step sea to determine whether the vehicle speed is equal to or higher than a predetermined vehicle speed Vo'. If the vehicle speed is equal to or higher than the predetermined vehicle speed Vo', the control circuit 200 proceeds to step 813 to select the third speed shown in Table 3. 1 pattern (first solenoid valve 76
(ON pattern), and the predetermined vehicle speed vo'
If the value is less than 1, in step S14, a control signal A~ is sent to each of the solenoid valves 76 to 78 so that the second pattern of 3rd speed (the pattern in which the first solenoid valve 76 is OFF) is achieved.
C is output, and the shift to 3rd gear is completed.

By the way, the first to third solenoid valves 76 at 4th speed
The ON/OFF pattern of 78 is [ON, OFF, ON
1-2 in the hydraulic circuit 60 shown in FIG.
, 2-3, 3-4 The spools 71a to 73a of the shift valves 71 to 73 are located on the right, left, and right in the drawing, respectively, so that the servo apply pressure is applied by the line 112 and the 3-4 is applied by the line 113. In addition to the forward clutch 41 to which clutch pressure is supplied and which is always engaged, there are
The brake 45 and the 3-4 clutch 43 are engaged. In addition, the pattern of each solenoid valve 76 to 78 in 3rd speed is [ON, OFF, OFF] in the case of the first pattern.
], and the spool 7 of each shift valve 71 to 73
1a to 73a are located on the right, left, and left, respectively. Therefore, in addition to the above-mentioned 4-speed state, servo release pressure is further supplied through the line 116 to release the 2-4 brake 45, and the line 117 Coast clutch pressure is supplied and the coast clutch 42 is engaged.

On the other hand, the first intermediate pattern is [OFF, OFF, O
Since it is NI, if this first intermediate pattern is selected during the 4-3 gear shift, the first solenoid valve 76 is turned ON.
→0FF-4-ON, and the third solenoid valve 78 switches in the order of 0N-ON→OFF. Then, the first solenoid valve 76 is turned on and off as described above.
By switching, the spool 7 of the 1-2 shift valve 71
1a moves from right to left to right in the drawing of Fig. 2, and as a result, as shown by the symbol (A) in Fig. 5 (a), the servo apply pressure is drained at the start of the shift and once After a predetermined period of time T has elapsed, the fuel is supplied again and increases to a predetermined value. In addition, the third solenoid valve 78
is changed from ON to O after a predetermined time T has elapsed after the start of gear shifting.
Since the switching is to FF, the start of supply of servo release pressure and coast clutch pressure is delayed by time T from the start of decrease of the servo apply pressure, as shown by symbols (b) and (c) in FIG. As a result, the 2-4 brake 45 is
As shown by the symbol (D), the engagement force starts to decrease from the start of the shift, but since the supply of servo release pressure is slow, it is released slowly. Furthermore, since the engagement of the coast clutch 42 that operates the engine brake in 3rd gear is delayed, the 2-4 brake 45 is in a half-clutch state (see Fig. 5).
After the shaded part in a) continues for a relatively long time, the gear shifts to third gear. As a result, when the first intermediate pattern is selected, that is, when the vehicle speed is less than the predetermined vehicle speed ■o, during 4-3 shifting in a low vehicle speed region that does not require engine braking, and when the vehicle speed is above the predetermined vehicle speed 70, Also, during the 4-3 gear shift for acceleration while traveling at a constant speed, shift shock can be effectively reduced.

On the other hand, the second intermediate pattern of the first to third Renoid valves 76 to 78 is [OFF, OFF.

OFF], so if this second intermediate pattern is selected during 4-3 gear shifting, the first solenoid valve 76
is ON → OFF → as in the case of the first intermediate pattern above.
In contrast, the third solenoid valve 78 switches in the order of ON→OFF→OFF. In other words, in this case, the third solenoid valve 78 is turned on when the gear shift starts.
It switches from N to OFF, and therefore, as shown in Fig. 5(b).
As shown by symbols (e) and (f), the supply of servo release pressure and coast clutch pressure is started at the same time as the servo apply pressure starts to decrease. As a result, after the 2-4 brake 45 starts shifting, as shown by the symbol ct),
In addition to being quickly released, the coast clutch 42 is also engaged immediately after the shift starts. In this way, during a 4-3 shift in a high vehicle speed range of the vehicle speed during normal driving or a predetermined vehicle speed of 70 or higher, and also during a 4-3 shift for deceleration during constant speed driving in a high vehicle speed range, in other words, Then, when shifting from 4 to 3 in a state where engine braking is required, the shift to 3rd gear, where engine braking is activated, will occur quickly, thereby avoiding a dry running condition caused by a delay in engine braking. Ru.

In this embodiment, when the vehicle speed is below the predetermined vehicle speed ■o', the first solenoid valve 76 is turned off in the third gear after the 4-3 shift.
pattern is adopted. In this case, the solenoid valve 76 switches in the order of 0N-4OFF→○FF during the 4-3 shift, and after the servo apply pressure is drained at the start of the shift, it is not supplied again. Therefore, in this case No. 3
At high speed, only servo release pressure is supplied to the servo piston 45a, and the 2-4 brake 45 is released, but this reduces the shift shock when downshifting to 2nd speed, which is particularly noticeable at low vehicle speeds. This is to do so.

(Effects of the Invention) As described above, according to the present invention, in an automatic transmission equipped with a constant speed traveling device, especially when a predetermined downshift is performed during constant speed traveling, this downshift is during acceleration. Since the engagement state of the friction engagement element for engine braking during the gear shift is controlled depending on whether the gear shift is in progress or deceleration, shift shock is effectively reduced when downshifting during acceleration, and the shift shock is effectively reduced during deceleration. When downshifting, the engine brake is activated quickly to prevent the vehicle from running idle, resulting in a shift state suitable for each case.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a schematic diagram showing the mechanical configuration of an automatic transmission, FIG. 2 is a circuit diagram showing a hydraulic circuit, and FIG. 3 is a flowchart showing a control operation. Fig. 4 is a diagram showing the control region, and Figs. 5(a) and (b) are diagrams of changes in oil pressure and fastening force over time during 4-3 gear shifting when passing through the first intermediate pattern and the second intermediate pattern, respectively. It is. 10... automatic transmission, 20... torque converter,
30... Speed change gear mechanism, 41-46... Friction engagement element, 41a-46a... Actuator, 71-73
...Shift valve, 200...Control means (control circuit), 203...Constant speed traveling device. Figure 3 Figure 4 Figure 5rlJ

Claims (1)

[Claims] (1) A torque converter connected to the engine output shaft, a speed change gear mechanism arranged on the output side of the torque converter, a plurality of friction engagement elements that switch the power transmission path of the speed change gear mechanism, and each friction engagement element. The vehicle has a plurality of shift valves that control the supply and discharge of hydraulic fluid to and from the actuator, and is configured to obtain a plurality of gears depending on the combination of operating positions of these shift valves, and maintains the vehicle speed at a set vehicle speed. A shift control device for an automatic transmission equipped with a constant speed traveling device that outputs a downshift signal from the constant speed traveling device from a predetermined high gear to a predetermined low gear where engine braking is applied. Sometimes, there is an acceleration/deceleration determination means that determines whether a downshift occurs during acceleration or a downshift during deceleration, and when downshifting occurs during acceleration, the engine brake friction engagement element is not engaged from a high gear position to a low gear position. and a control means for switching from a high gear to a low gear via a state in which the frictional engagement element for engine braking is engaged when downshifting during deceleration. Shift control device for automatic transmission equipped with a device.