JPH0550625B2 - - Google Patents

Description

Detailed Description of the Invention A. Purpose of the Invention (Field of Industrial Application) The present invention provides an automatic gear shift system that switches a power transmission path through engagement/disengagement control of a gear shift means (for example, a hydraulically actuated clutch). Regarding the automatic transmission.

(Prior Art) An automatic transmission is configured to automatically change gears depending on driving conditions to obtain desired driving characteristics. For this reason, it is common practice to have a shift map in which shift-up lines and shift-down lines are set for each shift based on the relationship between vehicle speed and engine output, and to control the shift by comparing the driving conditions with this shift map. ing. An example of such speed change control is disclosed in Japanese Patent Application Laid-Open No. 189354/1983, for example.

When carrying out such speed change control, it is required to reduce shocks during speed change as much as possible, and various countermeasures have been taken in the past.

For example, when performing power-off shift-up (shift-up is performed by releasing the accelerator pedal while driving), when a shift command is issued, the front gear clutch (up to After that, the clutch for the rear gear is engaged when the input rotation and output rotation of the clutch for the rear gear (the clutch that is newly engaged due to gear shifting) are synchronized. There were controls in place to allow this. When such control is performed, there is no exchange of inertial energy between the input side and the output side when the rear clutch is engaged, so there is an advantage that a smooth gear change can be performed.

However, in this control, if the synchronization point of the input and output rotations of the rear clutch is detected using a timer or based on the relationship between vehicle speed and engine rotation, the influence of oil temperature may be affected. There is a problem that the detection accuracy is low due to the influence of variations due to individual differences, the influence of slips in torque converters, fluid couplings, etc. If the detection of the synchronization point is off, for example, the engagement timing of the rear gear clutch may become too early, causing a gear shift shock, or the engagement timing of the rear gear clutch may be delayed, causing a drop in engine rotation or a sense of discomfort due to a shift delay. There are problems that can occur.

For this reason, the applicant has proposed to detect the input/output rotational speed ratio (=output rotational speed/input rotational speed) of the input side rotating member and the output side rotational member of the hydraulically actuated clutch, and to detect the input/output rotational speed ratio Synchronization of input and output rotations is determined by detecting that the ratio has reached approximately 1.0, and when gear changes such as power-off or shift-up are performed, the hydraulic pressure supplied to the rear clutch is changed from the start of gear shifting. We proposed a control system in which the hydraulic pressure is maintained at a pressure slightly lower than the engagement starting hydraulic pressure until the input/output rotation synchronization is determined, and then this hydraulic pressure is raised to a predetermined engagement pressure after the input/output rotation synchronization is determined. (Gan Sho 63-50337).

(Problem to be Solved by the Invention) When the automatic transmission is controlled in this way, a smooth shift characteristic without a shift shock can be obtained, but the clutch for the rear gear is engaged from the start of the shift. Until then, both clutches are disengaged, so if the clutch pedal is depressed during this time, the throttle opening will open and the engine speed will rise rapidly, causing the engine to rev up. Also, there is a problem in that there is a risk that a shift shock may occur due to the engine revving up.

For this reason, when the clutch pedal is depressed after the start of gear shifting, the hydraulic pressure of the rear clutch is increased, and this clutch generates an engagement torque commensurate with the torque transmitted from the engine. It is thought that this will suppress the increase in speed and reduce the occurrence of gear shift shock. However, in the above-mentioned shift control, all clutches are in a disengaged state immediately before the clutch pedal is depressed, and even if engine torque is detected at this time, the torque required to absorb the inertial force of the rotating parts is low. However, if the oil pressure is set in accordance with this engine torque, it is difficult to solve the problems such as engine revving.

In view of the above, the present invention provides a shift control device that can smoothly shift gears without causing engine rotational speed up even when the accelerator pedal is depressed during power-off shift-up gear shifting. The purpose is to provide

B. Structure of the Invention (Means for Solving the Problems) As a means for achieving the above object, the shift control device of the present invention performs a power-off shift-up shift, as shown in the claim correspondence diagram in FIG. When the output is generated, the engagement force of the rear gear transmission means e for causing the transmission (power transmission means) f to select the power transmission path is set to the minimum;
Shift engagement force establishing means a that sets the engagement force of the shift means e to a predetermined engagement force when the input/output rotation speed ratio of the shift means e reaches a predetermined value, and a throttle opening that detects the engine throttle opening degree. degree detection means b
and a transmission torque prediction means c that predicts the transmission torque that would be generated in the transmission means e if the transmission means e for the rear stage was fully connected when the transmission means e for the rear gear is not engaged. During a power-off shift-up shift, when the engine throttle opening detected by the throttle opening detection means b exceeds a predetermined opening, the shift engagement force setting means a
Regardless of the setting, the engagement force of the rear gear shifting means e is
and a shift engagement force changing means d that sets a value corresponding to the torque predicted by the transmission torque predicting means c.

(Function) When the shift control device with the above configuration is used to perform shift control, when power-off system up is performed, the engagement force of the front gear shift means (e.g., hydraulic clutch) is released. The engagement of the transmission means e is released, and the engagement force of the rear-stage transmission means e is set to the minimum by the transmission engagement force setting means b, so that the rear-stage transmission means e remains disengaged. In accordance with the power-off state (the state in which the accelerator pedal is released), the engine speed decreases, and the input/output revolution speed ratio of the rear-stage transmission means e changes toward 1.0 (synchronization). Then, when the input/output rotation speed ratio of the rear-stage transmission means e reaches a predetermined value, the engagement force of the rear-stage transmission means is set to a predetermined value by the shift engagement force setting means b, and the engagement of the rear-stage transmission means is stopped. will be started.

Normally, gear change control is performed in this way, but when the throttle opening detection means b detects that the throttle opening has exceeded a predetermined opening during the power-off shift-up shift, In this case, the gear shift engagement force changing means d operates, and the engagement force of the rear gear shift means e is set to a value corresponding to the torque predicted by the transmission torque predicting means, thereby suppressing engine rotational speed up.

(Example) Hereinafter, specific examples will be described using the drawings.

First, with reference to FIG. 2, the configuration of an automatic transmission having a speed change control device according to the present invention will be explained. In this transmission AT, engine output transmitted from an output shaft 1 of the engine via a torque converter 2 is shifted by a transmission mechanism 10 having a gear train forming a plurality of power transmission paths. is output to. Specifically, the output of the torque converter 2 is output to an input shaft 3, and five sets of gear trains are arranged in parallel with each other between this input shaft 3 and a counter shaft 4 arranged parallel thereto. The speed is changed by one of them and transmitted to the counter shaft 4, and further output to the output shaft 6 via output gear trains 5a and 5b disposed between the counter shaft 4 and the output shaft 6.

Five sets of gear trains arranged between the input shaft 3 and the counter shaft 4 are first gear trains 11a and 11b.
, 2nd speed gear trains 12a, 12b, 3rd speed gear trains 13a, 13b, and 4th speed gear trains 14a, 14.
b, and reverse gear trains 15a, 15b, 15c
Each gear train includes a hydraulically actuated clutch 11 for transmitting power through that gear train.
c, 12c, 13c, 14c, and 15d are arranged. Note that a one-way clutch 11d is disposed on the first gear 11b. Therefore, by selectively engaging and disengaging these hydraulically actuated clutches, it is possible to select power transmission by any one of the five gear trains to perform a speed change.

The operation of the five sets of hydraulic clutches 11c to 15d is controlled by the hydraulic control valve 20.
This is done by hydraulic pressure supplied and discharged via hydraulic lines 21a to 21e.

The hydraulic control valve 20 is operated by operating a manual valve 25 connected via a wire 45a to a shift lever 45 operated by the driver, operating two solenoid valves 22 and 23, and operating a linear solenoid valve 56. Ru.

The solenoid valves 22 and 23 are connected to the signal line 3
The linear solenoid valve 56 is turned on and off by an operating signal sent from the controller 30 via the signal line 31c. A rotation signal from a first rotation sensor 35 that detects the input side rotation speed of the hydraulic clutch based on the rotation of the reverse gear 15c is sent to this controller 30 via a signal line 35a, and the rotation signal of the output gear 5b is sent to the controller 30 via a signal line 35a. A rotation signal from a second rotation sensor 32 that detects the output rotation speed of the hydraulically actuated clutch based on the signal line 32a is sent through the signal line 32a;
A throttle opening signal from a throttle opening sensor 33 that detects the opening of the engine throttle 41 is sent via a signal line 33a.

Shift control in the transmission configured as described above will be explained.

Shift control is performed according to a shift range set by the manual valve 25 in the hydraulic control valve 20 in response to the operation of the shift lever 45. For example, this shift range is
There are P, R, N, D, S, and 2 ranges, and in the P and N ranges, the fully hydraulically operated clutch 1
1c to 15d are disengaged and the transmission is in a neutral state, and in the R range, the reverse hydraulic clutch 15d is engaged and the reverse gear is set.
In the D range, S range and 2 range, gear changes are performed based on the shift map.

This shift map has, for example, a shift-up line and a shift-down line in a graph in which the vertical axis shows the throttle opening θ _TH and the horizontal axis shows the vehicle speed V, and the engine throttle opening (accelerator pedal When the running state determined by the amount of depression) and the vehicle speed crosses a shift up line in the up direction, an upshift is performed, and after the upshift, when the downshift line is crossed in the down direction, a downshift is performed.

Here, power-off upshift refers to a case where the accelerator pedal is released while driving, the throttle opening θ _TH becomes smaller, and the driving condition crosses the shift-up line from the down side region to the up side region and a shift up is performed. To tell.

When the shift up line or downshift line on the speed change map is crossed, an activation signal is output from the controller 30 to the solenoid valves 22 and 23 via the signal lines 31a and 31b, and the hydraulic control valve 20 is activated accordingly. When actuated, each hydraulically actuated clutch 11c-15d
Hydraulic pressure is supplied and discharged to perform upshifts or downshifts.

Therefore, the throttle opening sensor 33
The throttle opening detecting means referred to in the claims is constituted, the controller 30 constitutes a transmission torque predicting means, and the controller 30 and the hydraulic controller valve 20 constitute a shift engagement force setting means and a shift engagement force changing means.

This hydraulic control valve 20 will be explained with reference to FIG. 3.

In this control valve 20, the hydraulic oil in the oil tank 7 supplied from the pump 8 is guided to the regulator valve 50 via the line 101, and the regulator valve 50 regulates the pressure to a predetermined line pressure. This line pressure is led to the manual valve 25 via the line 110, which controls the operation of the manual valve 25 and the control valve 20.
With the operation of various valves in the hydraulically actuated clutches 11c, 12c, 13 for each speed stage, the line pressure is
c, 14c, and 15d, depending on the driving conditions, and the operation of each clutch is controlled.

Here, first, various valves within the control valve 20 will be explained. Check valve 52
is disposed downstream of the regulator valve 50 and prevents the oil pressure of the lubricating oil sent to the lubrication section of the transmission through the line 102 from exceeding a predetermined pressure. The modulator valve 54 reduces the line pressure sent through the line 103 to create a predetermined modulator pressure, and supplies hydraulic fluid at this modulator pressure to the lock-up of the torque converter 2 through the line 104. It is provided to a lockup clutch control circuit (not shown) for clutch control and is further routed via line 105 to first and second solenoid valves 22, 23 for shift valve actuation control.

The manual valve 25 is operated in conjunction with a shift lever 45 operated by the driver, and the manual valve 25 is operated in conjunction with a shift lever 45 operated by the driver.
It is located at any one of six positions R, N, D, S, and 2, and the line pressure from line 110 is selectively supplied to lines 25a to 25g according to each position.

The 1-2 shift valve 60, the 2-3 shift valve 62, and the 3-4 shift valve 64 are the first and second solenoid valves 2 when the manual valve 25 is in the D, S, or 2 position.
Line 106 according to ON/OFF operation of 2 and 23
These valves are operated and controlled by the action of modulated pressure supplied via a to 106f, and control supply and discharge of line pressure to clutches 11c, 12c, 13c, and 14c for 1st to 4th speeds.

The lines 106a and 106b are connected to the first solenoid valve 22 and also to the line 105 via the orifice 22a, so that
When the first solenoid valve 22 is de-energized, the port to the drain side is closed and the line 10
Hydraulic oil having a modulated pressure is supplied from the line 105 to the lines 6a and 106b, and when the electricity is turned on, the port to the drain side is opened and the pressure in the lines 106a and 106b becomes almost zero. Moreover, the lines 106c to 106f are connected to the second solenoid valve 23 and the orifice 23a.
It is also connected to the line 105 via the line 105, and when the second solenoid valve 23 is de-energized,
The port to the drain side is closed and the line 106c~
Hydraulic oil with modulated pressure is supplied from line 105 to line 106f, and when the above-mentioned energization is on, the port to the drain side is opened and line 1
The pressures from 06c to 106f become almost zero.

Here, the line 106a is connected to the right end of the 1-2 shift valve 60, the line 106b is connected to the right end of the 2-3 shift valve 62, and the line 106c is connected to the right end of the 2-3 shift valve 62.
is connected to the left end of the 1-2 shift valve 60, line 106e is connected to the right end of the 3-4 shift valve 64, and line 106f is connected to the 2-3 shift valve 62.
Connects to the left end of In addition, lines 106e, 106
f is manual valve 25 and line 106d
It is connected to the second solenoid valve 23 via. For this reason, the first and second solenoid valves 22,
By controlling the energization on/off of 23, each line 10
By controlling the supply and discharge of modulated pressure from the line 105 of 6a to 106f, 1-2, 2-3, 3-
The operation of the four shift valves 60, 62, 64 can be controlled, whereby the line pressure supplied from the line 110 via the manual valve 25 is applied to each hydraulically actuated clutch 11c, 12c, 13c,
14c to perform a desired speed change.

This control valve 20 is the first to fourth orifice control valves 70, 72, 74, 7
6, and these orifice control valves release the hydraulic pressure in the hydraulic chamber of the front clutch in synchronization with the rise in hydraulic pressure in the hydraulic chamber of the rear clutch during gear shifting. The first orifice control valve 70 controls the hydraulic release timing of the third gear clutch when shifting from third gear to second gear, and the second orifice control valve 72 controls the timing of hydraulic release of the third gear clutch when shifting from second gear to third gear or from second gear to fourth gear. The hydraulic release timing of the 2nd speed clutch is controlled by the 3rd orifice control valve 74, and the hydraulic release timing of the 4th speed clutch when shifting from 4th speed to 3rd speed or from 4th speed to 2nd speed is controlled by the 3rd orifice control valve 74. The valve 76 controls the hydraulic release timing of the third speed clutch when shifting from third speed to fourth speed.

Furthermore, each hydraulically actuated clutch 11c, 12c,
Accumulators 81, 82, 83, and 84 having pressure receiving chambers communicating with the hydraulic chambers 13c and 14c are provided, and the pressure receiving chambers of each of these accumulators are connected to the back facing via piston members 81a, 82a, 83a, 84a. Lines 121, 12 to the pressure chamber
2, 123, 124 are connected, and these lines 121, 122, 123, 124 are connected to line 1.
It is connected to the linear solenoid valve 56 via 20a, 120b and 120.

The linear solenoid valve 56 has a linear solenoid 56a, and controls the operating force of the linear solenoid 56a by controlling the current supplied to the linear solenoid _56a . ) can be controlled. Therefore, by controlling the current supplied to the linear solenoid 56a, it is possible to control the hydraulic pressure in the back pressure chamber of each of the accumulators 81 to 84, and thereby the hydraulic pressure chamber of the engagement clutch (rear stage clutch) during gear shifting. By controlling the hydraulic pressure, the engagement force of this clutch (transmission means) can be freely controlled.

Clutch pressure control valve 78
is a valve that is disposed on the line from the manual valve 25 to the 1-2 shift valve 60 and is operated in response to the control pressure _PTH regulated by the linear solenoid valve 56.
For this reason, each hydraulically actuated clutch 11c, 12c, 13 is connected via each shift valve 60, 62, 64.
The line pressure supplied to c and 14c (this is referred to as clutch pressure _PCL ) is controlled by the clutch pressure control valve 78 to control the above control pressure.
Controlled according to P _TH . In addition, the control pressure
P _TH is controlled to be a pressure that corresponds to the accelerator pedal opening, that is, the engine output, except when shifting. Therefore, the clutch pressure P _CL for each clutch actuation is controlled to the required torque that corresponds to the engine output. The pressure can be as low as possible to obtain capacity.

Control valve 2 configured as above
0, the manual valve 25 is actuated by operating the shift lever 45 and the solenoid valves 22 and 23 are turned ON and OFF to actuate each of the above-mentioned valves, thereby selectively supplying line pressure to each of the clutches 11c to 15d. , automatic gear shifting is performed, but since its operation is conventionally known, its explanation will be omitted.

In the transmission configured as described above, shift control when a power-off shift-up is performed will be explained using the flowchart of FIG. 4 and the graph of FIG. 5.

In this control, first, in step S2, the target speed S _a is determined from the speed change map for the current speed S _O.
is searched, and in step S4 both speed stages S _O and S _a
Calculate the input/output rotation speed ratio (=output rotation speed/input rotation speed) e _CLO and e _CLa at .

Next, in step S6, both speed stages S _O ,
Determine whether S _a is equal. S _a = S _O occurs when a shift command is not output. In this case, the process proceeds to steps S8 to S12 and the shift judgment timer is set.
Restart _T1 , set the clutch pressure _PCL to the maximum pressure, and maintain the current speed stage _SO .

This state is shown in the portion up to time _t1 in FIG. 5A, in which the shift command from the controller 30 and the outputs of the shift solenoids 22 and 23 are designed to set the current speed stage _S0 . Therefore, the current speed S _O and the target speed S _a are the same, and the input/output speed ratio at the clutch for this speed is
e _CLO (=e _CLa ) is 1.0. Furthermore, the control pressure P _TH is set to the maximum by the linear solenoid valve 56, and the clutch pressure P _CL of the hydraulically operated clutch (transmission means) that sets the current speed gear is accordingly increased.
has also reached its maximum.

In this state, when the accelerator pedal is released at time t ₁ and the throttle opening θ _TH becomes small, and a shift up command is output in response, the target speed S _a is newly set. Therefore, S _a ≠ S _O , and the process proceeds to step S14, where it is determined whether S _a > S _O , that is, whether or not it is a shift up. In case of downshift,
Proceeding to step S16, a gear change process for this purpose is performed. If the shift is up, the process proceeds to step S18, where it is determined whether or not the power is on; if the power is not on, the process proceeds to step S16, where a corresponding speed change process is performed. In addition, since the present invention deals with power-off shift-up, other gear change control, that is, step
A description of the control at S16 will be omitted. Note that the current speed S _O when a speed change command is output and a speed change is performed is the front speed, and the target speed S _a is the rear speed.

If it is a power-off shift-up, proceed to step S20, wait for the shift judgment timer _T1 to elapse from the output of this shift command, and then proceed to step S20.
Proceed to S22. This shift judgment timer _T1 is used to prevent the shift busy feeling caused by shifting according to the shift command when the shift command is changed within a short time, for example. , after the shift command from 2nd gear to 3rd gear is output,
If a shift command from 3rd to 4th gear is further output before the shift judgment timer _T1 has elapsed, the shift from 2nd to 4th gear will not be executed when the shift judgment timer _T1 has elapsed. It will be done.

Therefore, as shown in FIG. 5, when a shift command from the current speed S _O to the target speed S _a is output at time t ₁ , at time t ₂ after the shift judgment timer T ₁ has elapsed. , the shift solenoid output is S _O
will be changed from to S _a . However, when the gear shift command is output at time _t1 , the target speed gear S _a is changed to one corresponding to this command, and therefore, as shown in FIG. 5A, the target speed gear (later gear) clutch engages. The output rotational speed ratio e _CLa is changed at time t ₁ to the value e ₁ at the clutch of this target speed gear.

When the shift solenoid output is changed to S _a at time t ₂ , the clutch pressure P _CLO of the hydraulic clutch for the current speed S _O (previous stage) is released to the drain side and rapidly decreases. At the same time, the hydraulic pressure of the clutch for the target speed S _a (for the rear gear) is set, and the power-off upshift is actually started.

After this start time _t2 , as shown in step S22, the throttle opening value TH detected by the throttle opening sensor 33 is changed to a predetermined opening value.
The judgment value DTH is calculated by subtracting CTH, and the positive or negative of this judgment value DTH is determined (step
S24). This reference value CTH is a reference value for determining whether or not the accelerator pedal has been depressed in the power-off state, and as shown in the diagram (top diagram) showing changes in throttle opening in Figure 5, The throttle opening value TH (the value indicating the throttle opening θ _TH at this time) in the power-off state is smaller than the reference value CTH, but if the throttle opening increases when the accelerator pedal is depressed from this state, as shown in Figure 5. B
As shown in , the throttle opening value TH is the reference value.
Becomes larger than CTH. Therefore, in the power-off state, the judgment value DTH is negative, and when the accelerator pedal is depressed, the judgment value DTH becomes positive.

First, a case will be described in which the gear shift is performed while the judgment value DTH remains negative. Incidentally, changes in various control values during this shift are shown in FIG. 5A.

In this case, the process advances to step S28, and the input/output rotation speed e _CLa at the target speed clutch is set to a predetermined value e _CSPU.
If e _CLa < e _CSPU , that is, the input/output rotation speed ratio of the target speed stage e _CLa
has not yet reached the predetermined value e _CSPU ,
In step S30, clutch pressure _PCL is set to a minimum value.

This setting is performed by minimizing the control pressure P _TH by the linear solenoid valve 56, and when the clutch pressure P _CL is at the minimum, the target speed clutch is in a disengaged state. At this time, the engine is in the power-off state), so the engine speed rapidly decreases, and the input side rotation speed of the clutch for the target speed also rapidly decreases accordingly, and the input/output speed ratio e _CLa of this clutch rapidly decreases. changes toward 1.0.

Then, when e _CLa ≧ e _CSPU (time t ₃ ), the process advances to step S32 and the transmission torque ETQ is set to a predetermined value.
Set GET, then this rotation speed ratio e _CLa is 1.0
-α (however, α is an extremely small value), in other words, it is determined whether the clutch for the target speed gear is almost engaged (step
S34). If e _CLa < (1.0 - α), that is, if the target speed clutch is still in the semi-engaged state, the process proceeds to steps S36 and S38, and the engagement judgment timer is set.
The _TFC is restarted and the clutch pressure _PCL (ETQ) necessary to generate the transmission torque ETQ (=GET) set in step S32 is set.

After this, the input/output rotation speed of the clutch for the target speed stage is
e If _CLa is greater than (1.0 - α) and it is determined that this clutch is almost engaged, the step
After proceeding to S40 and waiting for the engagement determination timer _TFC to elapse (from time _t4 to _t5 ), the target speed S _a is set as the current speed S _O (step S42). Therefore, in the next flow, in step S6,
It is determined that S _a = S _O , and the process proceeds to steps S8 to S12.
The clutch pressure _PCL is increased to the maximum pressure (predetermined engagement pressure).

Note that the clutch pressure _PCL may be increased to the maximum at the time when the clutch for the target gear is engaged (time _t4 ), but there may be some clutch slippage at time _t4 . In many cases, if the clutch pressure is increased to the maximum in this state, this slight slippage may be absorbed suddenly and shift shock may occur. In particular, as shown in Fig. 8, the friction coefficient of the clutch friction member often has a characteristic that it increases rapidly near the point where the relative rotation becomes zero, and the torque fluctuation ( (increase) is large, so even if a slight amount of slippage is absorbed, there is a high possibility that the accompanying torque fluctuation will become large and the shift shock will become large.

For this reason, as mentioned above, in this control, an engagement judgment timer T _FC is provided, and e _CLa ≧ (1.0 − α)
state (state in which the target speed gear clutch is engaged)
If the clutch pressure PCL continues for a time longer than the time set by the timer _TFC , the clutch pressure _PCL is increased to the maximum pressure. In this way, the clutch pressure P _CL
When the pressure is increased to the maximum pressure, the slippage in this clutch is completely eliminated, and the shift shock described above is no longer generated.

Next, the accelerator pedal is depressed while changing gears,
The case where the throttle opening value TH becomes larger than the reference value CTH and the judgment value DTH≧0 will be explained. Each control value in this case changes as shown in FIG. 5B.

In this case, step S24 to step S26
Proceed to calculate the predicted transmission torque ETQ. The predicted transmission torque ETQ refers to the torque from the engine that is transmitted through the target speed clutch when the clutch is engaged _. It is determined by reading from a graph set from the relationship between Ne and engine speed Ne. Note that this torque ETQ is generally proportional to the throttle opening θ _TH , so this torque is calculated by multiplying the throttle opening θ _TH by a predetermined coefficient k.
A simple method for calculating ETQ may also be used. Furthermore, as shown in Fig. 7, the clutch pressure P _CL required to obtain this torque ETQ is calculated and set corresponding to this torque ETQ, and from this graph, the clutch pressure required to generate the above torque ETQ is calculated. Pressure P _CL reads (ETQ). Note that this clutch pressure P _CL (ETQ) is the linear solenoid valve 5.
6 to set the control pressure P _TH to a predetermined value P _TH
(ETQ).

Once the predicted transmission torque ETQ has been calculated in this way, the process then proceeds to step S34, and the control from step S34 onwards is performed. However, in this control, the clutch pressure _PCL at step S38 is
Clutch pressure corresponding to the predicted transmission torque ETQ above
P _CL (ETQ). Therefore, as shown in Fig. 5B, the control pressure P _TH is set to P _TH (ETQ) from time t ₁₃ when the judgment value DTH becomes positive, and correspondingly, the clutch pressure P _CL is set to the predicted transmission value. Torque ETQ
The hydraulic pressure P _CL (ETQ) that generates the same torque as

As a result, when the accelerator pedal is depressed during a power-off shift-up, the engagement capacity of the rear gear clutch is set to the predicted transmission torque ETQ, and the increase in engine output due to the depression of the accelerator pedal is absorbed by the rear gear clutch. . As a result, the engine speed does not speed up, and gear shifts are performed smoothly and without shock.

In this example, the clutch pressure P _CL is the control pressure that acts as back pressure of the accumulator.
Although an example in which control is performed using P _TH has been shown, the present invention is not limited to this, and for example, the clutch pressure may be configured to be directly controlled by a linear solenoid valve, etc. The control pressure P _TH may be generated by a duty-controlled solenoid valve.

C. Effects of the Invention As explained above, according to the present invention, in the case of power-off shift-up, basically, when the output that causes this shift is generated, the engagement force of the rear gear shifting means is minimized. The engagement force is set to a predetermined value when the input/output rotation speed ratio of this rear gear transmission means reaches a predetermined value. When the opening degree exceeds a predetermined opening degree, the transmission engagement force changing means operates to set the engagement force of the rear gear transmission means to a value corresponding to the torque predicted by the transmission torque prediction means. Therefore, the increase in engine output caused by depression of the accelerator pedal can be absorbed by the rear-stage clutch, preventing the engine from speeding up and allowing smooth, shock-free gear shifting.

[Brief explanation of the drawing]

FIG. 1 is a claim correspondence diagram showing the structure of the present invention;
FIG. 2 is a schematic diagram showing an automatic transmission equipped with a control device according to the present invention, FIG. 3 is a hydraulic circuit diagram showing a hydraulic control valve constituting the control device, and FIGS. 4 and 5 are diagrams showing the control device described above. A flowchart and a graph showing the control contents by the device, FIG. 6 is an explanatory diagram for calculating the predicted transmission torque, and FIG. 7 is a graph showing the relationship between the predicted transmission torque and the clutch pressure.
FIG. 8 is a graph showing the relationship between the relative rotational speed of the clutch and the coefficient of friction of the friction member. 2...Torque converter, 10...Transmission mechanism,
20... Hydraulic control valve, 22, 23...
...Shift solenoid valve, 25...Manual valve, 32, 35...Rotation sensor, 56...Linear solenoid valve.

Claims (1)

[Scope of Claims] 1. A power transmission means that constitutes a plurality of power transmission paths, and a plurality of speed change means that are controlled to engage and disengage in order to select the power transmission path by this power transmission means. In an automatic transmission, when a power-off shift-up gear change is performed, the engagement force of the rear gear transmission means is set to the minimum when the output for performing this gear change is generated, and the input/output rotation speed ratio of this transmission means is set to the minimum. transmission engagement force setting means for setting the engagement force of the transmission means to a predetermined engagement force when the transmission means reaches a predetermined value; a throttle opening detection means for detecting an engine throttle opening degree; transmission torque predicting means for predicting the transmission torque that would be generated in the transmission means if the transmission means was fully engaged when the transmission is engaged; When the engine throttle opening detected by the opening detecting means exceeds a predetermined opening, the engaging force of the rear gear shifting means is determined by the transmission torque predicting means, regardless of the setting of the shifting engaging force setting means. 1. A shift control device for an automatic transmission, comprising a shift engagement force changing means for setting an engagement force corresponding to a predicted torque.