JP2820434B2 - Transmission control device for automatic transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a shift of an automatic transmission in which an operation of a transmission mechanism in an automatic transmission provided in a vehicle or the like is controlled using hydraulic pressure. It relates to a control device.

(Prior Art) As an automatic transmission provided in a vehicle, an automatic transmission in which a torque converter and a multi-gear type transmission mechanism are combined is widely used. In such an automatic transmission,
Normally, a hydraulic circuit section is provided in which a supply and discharge operation of hydraulic pressure is controlled by a control unit constituted by using a microcomputer, and a plurality of friction clutches such as clutches and brakes built in the transmission mechanism are provided from the hydraulic circuit section. By selectively supplying the hydraulic pressure to the mating element, each of the friction engagement elements is engaged or released, and the shift range and the shift speed in the transmission mechanism are switched.

In an automatic transmission provided with such a hydraulic circuit portion,
For example, the fastening and release of a band brake, which is one of the friction engagement elements, is performed by adjusting the tightening strength of a band provided therein, and the adjustment of the tightening strength of the band is performed by hydraulic pressure. The operation is performed by driving means whose operating state is controlled. In such a band brake, when the shift lever operated to select the shift mode is in the drive range position, when the state is switched from the engaged state to the released state or from the released state to the engaged state, If the time required for the switching is not set to be appropriate, a large shift shock may occur. Therefore, for example, as shown in JP-A-61-278649, with the shift lever in the drive range position,
A band brake which is changed from a released state to an engaged state when downshifting from the third speed to the second speed in the automatic transmission, wherein the hydraulic pressure acting on the driving means for controlling the tightened state of the band is the operating state of the engine. The time required for reducing the hydraulic pressure that causes the switching from the released state to the engaged state is controlled by the electronically controlled hydraulic pressure adjusting means controlled according to
Four brakes are known.

(Problems to be Solved by the Invention) In the 2-4 brake which is a band brake in the automatic transmission, not only the problem of the shift shock due to the switching from the released state to the engaged state as described above, but also the engaged state. Shift shocks and other undesirable phenomena arising from switching from the state to the released state are also problematic. For example, upshifting from the second gear to the third gear while the shift lever is in the drive range position usually involves changing the 2-4 brake from the engaged state to the released state and the 3-4 brake.
This is performed by changing the clutch from the disengaged state to the engaged state. In such a case, the reduction speed of the hydraulic pressure acting on the driving means for controlling the tightening strength of the 2-4 brake band is 3
-4 If the speed is lower than the rising speed of the hydraulic pressure acting on the clutch, the decrease period of the torque obtained on the output shaft of the automatic transmission during the switching operation becomes longer, thereby causing a large shift shock to the engine. In addition, there is a problem that the reliability of the 3-4 clutch is deteriorated. Therefore, it is desirable that the hydraulic pressure acting on the 2-4 brake be rapidly reduced.
If the hydraulic pressure acting on the four clutches is too fast compared to the rising speed, the engine may be blown up. The problems at the time of switching the engaged state of the 2-4 brake from the engaged state to the released state are that the hydraulic pressure acting on the driving means for controlling the tightening state of the band as described above is controlled according to the operating state of the engine. It cannot be dealt with by means of adjusting the pressure by electronically controlled hydraulic pressure adjusting means. Conventionally, the reduction speed of the hydraulic pressure acting on the driving means is compromised from the viewpoint of engine blow-up, It is not fast.

In view of such a point, the present invention provides, for example, a shift operation in which the engagement state of a plurality of frictional engagement elements incorporated therein is switched by a transmission mechanism provided in an automatic transmission, for example,
A specific frictional engagement element, such as a 2-4 brake, is switched from an engaged state to a released state when a specific shift operation such as an upshift from the second gear to the third gear is performed. It is an object of the present invention to provide a shift control device for an automatic transmission in which the time required for the automatic transmission can be made appropriate without causing inconvenience such as the engine blowing up.

(Means and Actions for Solving the Problems) In order to achieve the above object, a shift control device for an automatic transmission according to the present invention activates a plurality of frictional engagement elements incorporated in a shift mechanism in the automatic transmission. Operating hydraulic pressure supply unit 3 for supplying operating hydraulic pressure to change the engagement state of the plurality of frictional engagement elements, and switching of the first frictional engagement element from the disengaged state to the engaged state. When a specific operation involving switching from the engaged state to the released state of the second frictional engagement element is performed, a driving unit that drives the second frictional engagement element, and a driving unit and an operating hydraulic pressure supply unit are provided. An auxiliary hydraulic adjustment passage connected to an oil passage to be connected and having a passage resistance smaller than that of the oil passage; and an opening / closing control means provided in the auxiliary hydraulic adjustment passage and selectively making the auxiliary hydraulic adjustment passage conductive. A gear shift state that detects a specific gear shift operation State detecting means, a torque detecting means for detecting a torque obtained on an output shaft of the automatic transmission, and an operation control means, wherein the operation control means detects a specific shift operation by the shift mode detecting means. When the torque detecting unit detects that the rate of change in torque is negative, the opening / closing control unit performs an operation of bringing the auxiliary hydraulic pressure adjustment passage into a conductive state.

(Embodiment) FIG. 2 shows an example of a shift control device for an automatic transmission according to the present invention, together with an automatic transmission for a vehicle to which the shift control device is applied.

In FIG. 2, an automatic transmission 10 has a torque converter
14 and a multi-gear transmission mechanism 20, and the hydraulic pressure used for controlling their operation is supplied from a hydraulic circuit section 40.

The torque converter 14 includes a pump impeller 14a, a turbine runner 14b, a stator 14c, and a case 11, and an oil pump 15 is connected to an output shaft 12 of an engine to which the pump impeller 14a is connected via a pump drive shaft 16. I have. The turbine runner 14b is connected to the output shaft 12 and to a transmission mechanism 20 via a hollow turbine shaft 17, and a one-way clutch 18 is interposed between the stator 14c and the case 11. , Stator 14c
However, it is configured to rotate in the same direction as the pump impeller 14a and the turbine runner 14b.

The transmission mechanism 20 includes a planetary gear unit 21 for obtaining four forward steps and one reverse step. The planetary gear unit 21 includes a small-diameter sun gear 22, a large-diameter sun gear 23, a long pinion gear 24, a short pinion gear 25, and a ring gear 26. Between the small-diameter sun gear 22 and the turbine shaft 17, a forward clutch 27 and a coasting clutch 28 for traveling forward are arranged in parallel, and the small-diameter sun gear
Between the clutch 22 and the forward clutch 27, a one-way clutch 29 is interposed. Large diameter sun gear 23 and turbine shaft 17
, A reverse clutch 30 for reverse travel is provided, a 2-4 brake 31 is provided, and a 3-4 brake is provided between the long pinion gear 24 and the turbine shaft 17.
A clutch 32 is provided. The long pinion gear 24 is connected to a transmission case 35 via a carrier 33 and a one-way clutch 34. The carrier 33 and the transmission case 35 are disengaged by a low reverse brake 36. The ring gear 26 is connected to an output gear 38 via an output shaft 37 of the automatic transmission 10, and the output shaft 37
Is transmitted to the front wheels, which are the driving wheels of the vehicle, via a differential gear unit (not shown) and the like.

In the multi-gear transmission mechanism 20 having such a configuration, the forward clutch 27, the coasting clutch 28, the reverse clutch 30, the 2-4 brake 31, the 3-4 clutch 32, and the low / reverse brake are friction engagement elements. 36
Are appropriately selected and operated, so that a P range (parking range), an R range (reverse range), an N range (neutral range), and a D range, an S range (2 ranges) and a forward range are formed. L range (1
Range) and each of the first to fourth speeds in the forward range. The operating relationships of the clutches 27, 28, 32 and 30 for obtaining the respective ranges and shift speeds, and the brakes 31 and 36, and the one-way clutches 29 and 34 when the respective ranges and shift speeds are obtained.
The operating state of is shown in the table.

The clutches 27, 28,
The operating oil pressure for operating each of the brakes 32 and 30 and the brakes 31 and 36 is formed in a hydraulic circuit unit 40 that is controlled by the control unit 100.

The control unit 100 has a detection output signal St obtained from a throttle opening sensor 51 for detecting the opening of a throttle valve arranged in the intake passage, and a turbine speed sensor 52 for detecting the rotation speed of the turbine runner 14b. Detected output signal Sr, a detected output signal Sv obtained from a vehicle speed sensor 53 for detecting the vehicle speed, and a detected output signal obtained from a shift position sensor 54 for detecting the operating position of the shift lever 55
Ss and a detection output signal Sq obtained from a torque sensor 56 for detecting a torque obtained on an output shaft 37 of the automatic transmission 10 are supplied, and other signals Sx necessary for controlling the automatic transmission 10 are also supplied. Is done.

The control unit 100 performs a shift control in the automatic transmission 10 based on the various signals described above.

When the shift control is performed by the control unit 100,
The shift characteristic line previously mapped and stored in the built-in memory in the control unit 100 includes the detection output signal St and
The throttle opening and the vehicle speed represented by Sv are collated to determine whether a shift-up condition or a shift-down condition is satisfied.

If it is determined that the shift-up condition or the shift-down condition is satisfied, the drive signals Ca, Cb, and Cc are selectively supplied from the control unit 100 to the solenoid valves 61 to 63 provided in the hydraulic circuit unit 40. Is done. Thereby,
The operation state of various shift valves and the like disposed in association with each of the solenoid valves 61 to 63 is changed, and supply / discharge control of operating hydraulic pressure to each of the plurality of friction engagement elements in the transmission mechanism 20 is performed. They are selectively engaged or released as shown in the table above to achieve the desired gear.

The control unit 100 supplies the drive signal Ce to the solenoid valve 65 provided in the hydraulic circuit unit 40 when the upshift condition from the second speed to the third speed is satisfied, and releases the engagement state of the 2-4 brake 31. It controls the switching operation to the state.

The 2-4 brake 31 has a known configuration having a brake drum and a band for tightening the brake drum, and its engagement and release is provided in each friction engagement element of the transmission mechanism 20 and the hydraulic circuit unit 40. As shown in FIG. 1 showing the relationship with each shift valve, the tightening strength of the band is adjusted by the drive valve 31A. The drive valve 31A includes a back pressure chamber 31a connected to an oil passage 83, an internal pressure chamber 31b connected to a pressure adjusting oil passage 84 to which one end of a bypass 82 is connected, a valve body 31d, and a valve body 31d. 2-4 It has a rod 31c that connects the band of the brake 31. For example, when switching from the released state to the engaged state, the operating oil pressure for the internal pressure chamber 31b is higher than the operating oil pressure for the back pressure chamber 31a. Is increased, whereby the valve body 31d is moved rightward in FIG. 1 together with the rod 31c, so that the tightening strength of the band is increased.

One end is connected to the pressure adjusting oil passage 84, and the bypass 82 has a passage resistance smaller than that of the pressure adjusting oil passage 84.
Is a pressure regulating valve 42 provided with a normally closed solenoid valve 65.
Port f. In addition, pressure adjustment oil passage
As shown in FIG. 1, an orifice is provided at a portion upstream of the portion to which the bypass 82 is connected, so that the passage resistance of the pressure adjusting oil passage 84 is smaller than the passage resistance of the bypass 82. It is going to be bigger. The port g of the pressure regulating valve 42 is connected to the oil passage 85 via the oil passage 80, so that the supply of the drive signal Ce from the control unit 100 to the solenoid valve 65 is stopped, and the pressure control valve 42 is turned off. Then, the bypass 82 is made conductive by the action of the line pressure supplied through the port g.

In the hydraulic circuit section 40 in which the drive valve 31A is interposed as described above, the hydraulic pressure discharged from the oil pump 15 is supplied to the regulator valve 70 through the oil passage 86 as shown in FIG. The hydraulic pressure supplied to the regulator valve 70 is adjusted to a line pressure, supplied from the regulator valve 70 to the throttle pressure generating valve 72 via an oil passage 85, and
It is supplied to the manual valve 73 via 87. Such an oil passage 87
Line pressure through the branch passage 87a.
1-2 shift valve 7 whose operating state is changed by 1
5 to a 2-3 shift valve 76 whose operating state is changed by a solenoid valve 62 through a branch path 87b, and a 3-4 shift valve 77 whose operating state is changed by a solenoid valve 63 through a branch path 87c. Is also supplied.

The throttle pressure generating valve 72, to which the line pressure is supplied through the oil passage 85, is configured such that the position of a spool provided in the throttle pressure generating valve 72 is changed according to the opening degree of the throttle valve disposed in the intake passage, whereby the line The pressure is adjusted to a value corresponding to the opening of the throttle valve to form a throttle pressure. The throttle pressure generated at the throttle pressure generating valve 72 is supplied to a throttle modulator valve 74 through an oil passage 88. The throttle modulator valve 74 changes the position of a spool provided in accordance with the supplied throttle pressure.When the throttle pressure is less than a predetermined value, the throttle modulator valve 74 passes the throttle through an oil passage 89 to a regulator. The throttle pressure is supplied to the valve 70, and when the throttle pressure becomes equal to or more than a predetermined value, the throttle pressure is adjusted by adding a correction according to the torque generated by the engine, and supplied to the regulator valve 70 as a pilot pressure.

On the other hand, the manual valve 73 to which the line pressure is supplied through the oil passage 87 has the spool 73a provided therein when the shift lever 55 is in the D range position, as shown in FIG. Ports a and e connected to oil passage 87
And the port b take a position where the communication state is established. In such a state, the line pressure supplied from the oil passage 87 is supplied from the port b to the accumulator 44 and the forward clutch 27 through the oil passages 90, 91, and 92,
The forward clutch 27 is in the engaged state.
The line pressure is supplied to the 3-4 shift valve 77 through oil passages 93a and 93b branched from the oil passage 91, and is supplied to the 3-4 shift valve 77.
From the oil passage 83 and an oil passage 94 connected thereto in a predetermined manner, and selectively supplied to the back pressure chamber 31a and the coasting clutch 28 of the drive valve 31A. Further, the line pressure is supplied to the 1-2 shift valve 75 through an oil passage 90, and is led out from the 1-2 shift valve 75 to a pressure adjusting oil passage 84 connected thereto according to a predetermined mode, and the internal pressure of the drive valve 31A is increased. While being selectively supplied to the chamber 31b,
The oil is supplied to the three-shift valve 76 through oil passages 90, 91 and 95.
The line pressure supplied to the 2-3 shift valve 76 is led out to an oil passage 96 connected thereto according to a predetermined mode, and supplied to the timing valve 78. The timing valve 78 is connected to a throttle pressure generating valve 72 via an oil passage 88, and is also connected to a timing valve 79 via an oil passage 81. Then, the line pressure supplied to the timing valve 78 is
Along with the line pressure through a, the oil passage 97 and its branch passage 97a
To the accumulator 45, to the 3-4 clutch 32 through the branch path 97b, and further to the accumulator 46 connected to the drive valve 31A through the branch path 97c.

As described above, when the shift speed is set to the second speed while the shift lever 55 is in the D range position, the drive signals Ca to Cc are supplied to the solenoid valves 61 to 63, respectively. Is assumed to be in the ON state. In such a case, the coasting clutch 28, the 3-4 clutch 32 and the drive valve 31A
No line pressure is supplied to the back pressure chamber 31a, and the line pressure is supplied to the internal pressure chamber 31b of the drive valve 31A. As a result, the coasting clutch 28 and the 3-4 clutch 32 are released, and the 2-4 brake 31 is connected to the rod 31c of the drive valve 31A.
Is moved to the right in FIG. 1 to be brought into the fastening state.

Thus, the shift range is set to the D range, and
When the upshift condition from the second speed to the third speed is satisfied in the state where the speed is set to the first speed, first, the supply of the drive signals Ca and Cb to the solenoid valves 61 and 62 is stopped, and they are turned off. After being identified, the solenoid valve 63
The supply of the drive signal Cc to the solenoid valve 61 is stopped, and immediately thereafter, the supply of the drive signal Ca to the solenoid valve 61 is started. In such a state, the line pressure is supplied to the coasting clutch 28 to be engaged, and
The line pressure is also supplied to the −4 clutch 32, and the 3-4 clutch 32 changes its operating oil pressure as shown by a line CP in FIG.
It is brought into the fastening state. In the drive valve 31A, first, after the supply of the line pressure to the internal pressure chamber 31b is stopped, the supply of the line pressure to the back pressure chamber 31a is started, and immediately after the supply is started, the line pressure is again supplied to the internal pressure chamber 31b. In this state, the back pressure chamber 3 is moved from the internal pressure chamber 31b.
Since the operating oil pressure in 1a is large, the valve body 31d
Is pushed to the left in FIG. 1 with the rod 31c, and the 2-4 brake 31 is released. At this time, the control unit 100 changes the engagement state of the 2-4 brake 31 from the engaged state to the released state. Are controlled.

When the 2-4 brake 31 is switched from the engaged state to the released state, the operating oil pressure for the internal pressure chamber 31b in the drive valve 31A shifts from the second gear to the third gear as indicated by the line AP in FIG. 3A. At a time point tb when a predetermined period has elapsed from the time point ta when the up condition is satisfied, the supply of the line pressure to the back pressure chamber 31a is started.
It drops sharply at b. At such time tb,
As shown by the line TQ in FIG. 3B, the torque obtained on the output shaft 37 of the automatic transmission 10 is in a rising state,
If the operating oil pressure for the internal pressure chamber 31B is excessively reduced, the engine may be blown up.However, immediately after the supply of the line pressure to the back pressure chamber 31a is started, the supply of the drive signal Ca to the solenoid valve 61 is stopped. When the line pressure is also supplied to the internal pressure chamber 31b, the operating oil pressure for the internal pressure chamber 31b is prevented from being excessively reduced, and the change in the reduction is immediately reduced. In such a case,
If the torque available on the output shaft 37 decreases at time tc, as indicated by the line TQ in FIG. 3B, such a change is detected by the control unit 100 based on the detected output signal Sq, The supply of the drive signal Ce to the solenoid valve 65 is stopped, and it is turned off. As a result, the line pressure of the oil passage 85 is
The spool 42a provided to the pressure regulating valve 42 is pressed to the left in FIG. 1 to make the port f and the drain of the pressure regulating valve 42 communicate with each other, and the pressure regulating oil is The bypass 82 whose path resistance is smaller than that of the path 84 is made conductive. As a result, the operating oil pressure of the drive valve 31A with respect to the internal pressure chamber 31b is led out from the pressure adjusting oil passage 84 to the bypass 82, and is released through the port f of the pressure adjusting valve 42 and the drain communicating therewith.
As shown by the line AP in FIG. A, the operating oil pressure for the internal pressure chamber 31b after the time point tc is rapidly reduced, and at a time point td when a predetermined period TA has elapsed from the time point tc, the engagement state of the 2-4 brake 31 is changed. The switching to the release state ends.

In such a case, if the bypass 82 is not conducting at the time tc to promote a decrease in the operating oil pressure for the internal pressure chamber 31b, the change in the operating oil pressure for the internal pressure chamber 31b after the time tc is, for example, Line A in FIG. 3A
At time te, which is later than time td, the switch from the engaged state of the 2-4 brake 31 to the released state ends, and the period TB from time tc to time te is determined by P ′. The period is longer than the period TA.

As described above, by changing the switching operation of the 2-4 brake 31 at the time td when the short period TA has elapsed from the time tc, the change in the torque obtained on the output shaft 37 after the time tc is In FIG. 3B, the output shaft 37 in the case where the decrease in the operating oil pressure with respect to the internal pressure chamber 31b is not promoted after the time point tc, as represented by the line TQ, as represented by the line TQ '. Since the decrease is small compared to the change in the obtained torque, and it is assumed that the state is immediately changed from the reduced state to the increased state after time tc, the reduction period of the torque represented by the line TQ is It is set to be shorter than the torque reduction period represented by TQ '. As a result, occurrence of a large shift shock in the engine is suppressed, and
The reliability of the 3-4 clutch 32 is improved.

If a decrease in the torque obtained on the output shaft 37 is not detected even after the elapse of a predetermined period from the time point ta, the control unit 100 executes a step 2 to prevent a malfunction of the drive valve 31A.
The control of the switching operation of the −4 brake 31 from the engaged state to the released state is not performed.

Further, when the decrease in the torque obtained on the output shaft 37 is caused by a change in the opening degree of the throttle valve, it is possible to avoid a situation in which the decrease in the torque is erroneously detected as being caused by a gear shift operation. Therefore, even when the reduction change of the throttle opening detected based on the detection output signal St is larger than a predetermined value, the control unit 100 performs the switching operation of the 2-4 brake 31 from the engaged state to the released state. Control is not performed.

The control unit 100 that performs control as described above is configured using, for example, a microcomputer.
An example of a program executed by the microcomputer in such a case at the time of controlling the switching operation of the 2-4 brake 31 from the engaged state to the released state will be described with reference to the flowchart of FIG.

In the program shown in FIG. 4, after the start, various signals are captured in step 101, and in step 102, it is determined whether or not the shift lever 55 is in the D range position based on the detection output signal Ss. When the lever 55 is in the D range position, in step 103, the second speed is changed to the third speed based on the detection output signals St and Sv.
It is determined whether or not the condition for upshifting to the speed is satisfied.
When the condition for upshifting from the second gear to the third gear is satisfied, the routine proceeds to step 104. Step 102
When it is determined that the shift lever 55 is not at the D range position, and when it is determined in step 103 that the condition for upshifting from the second speed to the third speed is not satisfied, the process returns to step 101.

In step 104, it is determined whether the flag F is 1 or not.
At 105, the timer is started and at step 106
, The flag F is set to 1 and the routine proceeds to step 107. On the other hand, if the result of determination in step 104 is that flag F is 1, the process proceeds directly to step 107. In step 107, it is determined whether the rate of change ΔTH of the throttle opening is equal to or less than a predetermined negative value Th (ΔTH is negative and its absolute value is equal to or greater than the absolute value of Th) based on the detection output signal St. If the rate of change ΔTH is greater than the negative value Th, it is determined in step 108 whether or not a predetermined period TO has elapsed from the time point when the condition for shifting up from the second speed to the third speed is satisfied. If the period TO has not elapsed, it is determined in step 109 whether or not the rate of change ΔTQ of the torque obtained on the output shaft 37 of the automatic transmission 10 is smaller than 0 based on the detection output signal Sq. . As a result of the determination, when the change rate ΔTQ is 0 or more, step 101
And when the change rate ΔTQ is smaller than 0,
In step 110, a drive signal Ce is sent to the solenoid valve 65, and the routine proceeds to step 111.

In step 111, the timer is stopped. In step 112, the flag F is set to 0, and the process returns to step 101. On the other hand, in step 107,
When it is determined that the change rate ΔTH of the throttle opening is equal to or less than the negative value Th, and when it is determined that the period TO has elapsed in Step 108, the process proceeds to Step 111.
Perform steps 111 and 112 as described above,
Return to step 101.

FIG. 5 shows another example of the shift control device of the automatic transmission according to the present invention, and the drive valve 31 in the example shown in FIG.
Instead of the hydraulic circuit unit 40 having a configuration in which the bypass 82 is connected to the internal pressure chamber 31b of A, the oil passage 83 is connected to the back pressure chamber 31a of the drive valve 31A via an oil passage 83 connected thereto. FIG. 2 shows a hydraulic circuit 40 'having a configuration in which a bypass 98 having a reduced passage resistance is connected, and a pressure regulating valve 42' having a solenoid valve 65 is provided in the bypass 98. Is attached to the automatic transmission 10 shown in FIG. In FIG. 5, portions corresponding to the frictional engagement elements, the valves, and the like shown in FIG. 1 are denoted by the same reference numerals as those in FIG. In FIG. 5, furthermore, the same operation of each friction engagement element and each valve shown in FIG. 1 will be omitted.

In FIG. 5, a bypass 98 has one end connected to an oil passage.
The other end is connected to an oil passage 85 from which the line pressure from the regulator valve 70 is led out.
One end of an oil passage 80 to which a solenoid valve 65 is connected is connected to a port j of the pressure regulating valve 42 '.

When the shift-up range is set to the D range and the condition for upshifting from the second gear to the third gear is satisfied and the 2-4 brake 31 is switched from the engaged state to the released state, the line BP in FIG. As indicated by the above, the operating oil pressure for the back pressure chamber 31a in the drive valve 31A increases after the time t2 when a predetermined period has elapsed from the time t1 when the condition for shifting up from the second speed to the third speed is satisfied. At this time, the torque obtained on the output shaft 37 of the automatic transmission 10 is the sixth torque.
In FIG. B, it is assumed to rise as represented by line TQ, and thereafter, when it decreases at time t3, such a change is detected by the control unit 100 based on the detection output signal Sq, and the drive signal Ce for the solenoid valve 65 is generated. The supply is stopped, and the solenoid valve 65 is turned off. Thereby, the line pressure from the oil passage 85 is supplied to the pressure regulating valve 42 'through the port j via the oil passage 80, and the spool 42a' provided in the pressure regulating valve 42 'is moved rightward in FIG. Port h and port i of the pressure regulating valve 42 '
Are connected to each other, and the bypass 98 having a lower passage resistance than the oil passage 83 is connected. As a result, the drive valve 31A
Supply to the back pressure chamber 31a through the oil passage 83 and the oil passage 85
From which the line pressure is supplied through the ports i and h of the pressure regulating valve 42 ', and as shown by the line BP in FIG. 6A, the operating oil pressure to the back pressure chamber 31a after the time point t3 is rapidly increased. At the time point t4 when the predetermined period TA 'has elapsed from the time point t3, the switching of the 2-4 brake 31 from the engaged state to the released state ends.

At this time, if the supply of the line pressure to the back pressure chamber 31a of the drive valve 31A through the bypass 98 at the time t3 is not performed, the change in the operating oil pressure to the back pressure chamber 31a after the time t3 is, for example, In FIG. 6A, the switching from the engaged state to the released state of the 2-4 brake 31 is completed at a time point t5, which is later than the time point t4, as indicated by a line BP '. The period TB 'is longer than the period TA'.

As described above, the operation and effect obtained by setting the period TA ′ from the time point t3 to the time point t4 when the switching operation of the 2-4 brake 31 is completed to be shorter than the period TB ′ are as follows.
The operation and effect obtained by setting the period TA during the switching operation period of the 2-4 brake 31 shown in the example of FIG. 1 shorter than the period TB are the same. The same applies to the control mode by the control unit 100.

(Effects of the Invention) As is apparent from the above description, according to the shift control device for an automatic transmission according to the present invention, the transmission mechanism provided in the automatic transmission allows the plurality of frictional engagement elements incorporated therein to be controlled. Among the shift operations in which the engagement state can be switched, for example,
A specific shift operation is performed, such as switching from the disengaged state of the 3-4 clutch to the engaged state and switching from the engaged state of the 2-4 brake to the disengaged state, such as upshifting from the second gear to the third gear. At the time, for example, when the specific frictional engagement element such as the 2-4 brake is switched from the engaged state to the released state, the specific shift operation is detected by the shift mode detecting means, and the torque is detected by the torque detecting means. When it is detected that the rate of change of the vehicle speed becomes negative, the opening / closing control means performs an operation of bringing the auxiliary hydraulic pressure adjustment passage into a conducting state. The rate of change of torque due to the transition from the released state to the engaged state of another frictional engagement element such as a 3-4 clutch, which is switched from the released state to the engaged state when the speed change operation is performed. As soon as it becomes negative, the transition speed of the specific frictional engagement element from the engaged state to the released state, such as the 2-4 brake, is increased, whereby the specific frictional engagement element is released from the engaged state. The time required for switching to the state can be made appropriate without causing any inconvenience such as the engine blowing up. As a result, a shift shock can be suppressed, and another friction engagement element that is switched from the disengaged state to the engaged state when the specific frictional engagement element is switched from the engaged state to the released state, for example, When the specific frictional engagement element, which is a 2-4 brake, is switched from the engaged state to the released state, the reliability of other frictional engagement elements, such as the 3-4 clutch, which is switched from the released state to the engaged state, is improved. Can be planned.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a specific configuration of a main part of an example of a shift control device for an automatic transmission according to the present invention, together with a transmission mechanism provided in the automatic transmission. FIG. 2 is an automatic transmission according to the present invention. FIG. 3 is a schematic configuration diagram showing an example of a transmission control device of a transmission together with an automatic transmission for a vehicle to which the transmission is applied, and FIG.
A time chart for explaining the operation of the example shown in the figure,
FIG. 4 is a flowchart showing an example of a program executed by the microcomputer when the control unit shown in FIG. 2 is provided with a microcomputer, and FIG. 5 is a shift control of the automatic transmission according to the present invention. FIG. 6 is a schematic configuration diagram showing a specific configuration of a main part of another example of the device together with a transmission mechanism provided in the automatic transmission.
6 is a time chart for explaining the operation of the example shown in FIG. In the figure, 10 is an automatic transmission, 20 is a transmission mechanism, 31 is 2-4 brake, 31A is a drive valve, 31a is a back pressure chamber, 31b is an internal pressure chamber, 31c is a rod, 31d is a valve body, and 32 is 3- 4 clutches, 37 is the output shaft of the automatic transmission 10, 40 and 40 'are hydraulic circuits, 42 and 4
2 'is a pressure regulating valve, 51 is a throttle opening sensor, 53 is a vehicle speed sensor, 54 is a shift position sensor, 56 is a torque sensor, 82 and 98 are bypasses, 84 is a pressure regulating oil passage, 100
Is a control unit.

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F16H 59/00-61/12 F16H 61/16-61/24 F16H 63/40-63/48

Claims (3)

(57) [Claims] An operating hydraulic pressure supply unit for supplying operating hydraulic pressure for operating a plurality of friction engagement elements built in a transmission mechanism of an automatic transmission, and switching an engagement state of the plurality of friction engagement elements. When a particular one of the accompanying shift operations involves switching from the released state of the first frictional engagement element to the engaged state and switching from the engaged state to the released state of the second frictional engagement element, A drive unit for driving the second frictional engagement element, an auxiliary hydraulic adjustment passage connected to an oil passage connecting the drive unit and the operating oil pressure supply unit, and having a passage resistance smaller than the oil passage. Opening / closing control means provided in the auxiliary hydraulic pressure adjustment passage to selectively make the auxiliary hydraulic pressure adjustment passage conductive; shift mode detection means for detecting the specific speed change operation; and an output shaft in the automatic transmission. Torque that detects the resulting torque Detecting means, when the specific shift operation is detected by the shift mode detecting means, and when the torque detecting means detects that the rate of change of the torque is negative, the open / close control means A shift control device for an automatic transmission, comprising: an operation control unit configured to perform an operation of bringing the auxiliary hydraulic pressure adjustment passage into a conductive state. 2. The operation control means according to claim 1, wherein the change rate of the torque obtained on the output shaft of the automatic transmission becomes negative due to a change in the opening degree of the throttle valve disposed in the intake passage.
2. The shift control device for an automatic transmission according to claim 1, wherein the opening / closing control unit does not perform an operation of bringing the auxiliary hydraulic pressure adjustment passage into a conductive state. 3. A condition that the operation control means does not allow the opening / closing control means to perform an operation of bringing the auxiliary hydraulic pressure adjustment passage into a conductive state, the change in the opening degree of the throttle valve disposed in the intake passage portion being a predetermined change. 3. The method according to claim 2, wherein:
A shift control device for an automatic transmission according to claim 1.