JPH068666B2 - Shift control device for automatic transmission - Google Patents

Description

The present invention relates to a shift control device for an automatic transmission.

(Prior Art) An automatic transmission is generally provided with a speed change gear mechanism having a plurality of friction elements, and the power transmission path is switched, that is, the speed is changed, by engaging and releasing the friction elements.

In such an automatic transmission, how to appropriately set the engagement speed of the friction element is important for reducing the shift shock. That is, when shifting is performed by engaging a specific friction element, if the engaging speed is too slow, a so-called up-stroke phenomenon occurs in the engine, and conversely, if the engaging speed is too fast, the engine speed drops. A so-called pull-in phenomenon occurs, which is a major cause of shift shock. Therefore, for example, it is conceivable to increase the engagement speed for a predetermined time at the beginning of the shift and decrease the engagement speed at the end of the shift, but the difference in engine speed and engine load during the shift, and further This fastening speed is not always ideal due to individual differences, aging, etc.

The above-mentioned problem is likely to occur particularly when one of the two friction elements is opened and the other friction element (specific friction element) is fastened, and at the time of downshifting. . The above-mentioned problems will be described in detail by taking such a case as an example. For example, when shifting from the 3rd speed to the 2nd speed in the D (drive) range (1st speed 4th speed), the front clutch is engaged and the second brake is released in the 3rd speed, but the front clutch is opened. By releasing and engaging the second brake, the car is downshifted to the second speed. Here, such a hydraulic control system for the front clutch and the second brake generally has a common hydraulic supply system and hydraulic release system, and the hydraulic pressure for engaging the front clutch is used for releasing the engagement of the second brake. The drain passage is used as an opening hydraulic pressure, and the drain passage for releasing the front clutch from the engagement is used as a drain passage for releasing the opening hydraulic pressure for engaging the second brake.

As described above, in the automatic transmission in which the shift-down control is performed, shift shock may occur unless the operation timings of the plurality of gear-stage selecting friction members are appropriate. The reason for this is that from the 3rd speed in the D range described above to 2
An example will be described for downshifting to high speed.

That is, in this case, as the front clutch is released, the torque rotation speed of the torque converter changes from the rotation speed N ₃ at the third speed to the rotation speed N at the second speed as shown in FIG. 3 (A).
Only up to ₂ at the third speed and the rotational speed corresponding to the gear ratio at the second speed increases. Therefore, after the front clutch is disengaged, if the second brake is completely engaged at the time when the turbine speed reaches the rotation speed N ₂ at the 2nd speed, a smooth gear shift like the rotation speed characteristic shown in FIG. The shift shock is reduced. However, the rate of change of the turbine speed is not constant, and changes according to operating conditions that change moment by moment, such as the accelerator pedal depression amount (i.e., throttle opening), vehicle speed, engine speed, etc. is there. Therefore, for example, when the engagement timing of the second brake is too early, a double lock state occurs in which both the front clutch and the second brake are simultaneously engaged at the same time, and as shown in FIG. A so-called pull-in phenomenon occurs in which the user temporarily falls. On the contrary, when the engagement timing of the second brake is too late, both the front clutch and the second brake are temporarily released to be in the free state, and as shown in FIG. A so-called idling phenomenon occurs in which the rotation speed N ₂ at the second speed is further increased. like this,
A shift shock occurs due to the turbine speed pulling up or blowing up during a shift.

Therefore, for example, a hydraulic passage having a throttle element as disclosed in Japanese Patent Laid-Open No. 56-156543 is used as a drain passage for eliminating the opening pressure of the second brake to control the speed at which the opening pressure escapes. It is possible to adjust the operation timing between the front clutch and the second brake by this. However, as described above, the appropriate operating timings of the front clutch and the second brake constantly change according to the operating conditions, and thus it is difficult to always perform appropriate shift control with such a configuration.

(Object of the Invention) The present invention has been made in consideration of the above circumstances.
An object of the present invention is to provide a shift control device for an automatic transmission, which can always set an engagement speed of a specific friction element to be ideal and prevent a shift shock.

(Structure of the Invention) In order to achieve the above object, the present invention has the following structure. That is, as shown in a block diagram in FIG. 18, in an automatic transmission having a plurality of friction elements and provided with a transmission gear mechanism that switches the power transmission path to a plurality of stages by engaging and releasing operations of the friction elements. An engaging speed adjusting means for adjusting an engaging speed of a specific friction element of the speed change gear mechanism, and an engaging speed of the specific friction element to be engaged at the time of speed change when the power transmission path is switched by the speed change gear mechanism. A fastening speed control means for controlling the fastening speed adjusting means so as to speed up for a predetermined time, a rotation speed detection means for detecting the rotation speed of the input portion of the speed change gear mechanism, and an output of the rotation speed detection means, Depending on the change in the number of revolutions of the input part of the speed change gear mechanism at the time of the current speed change,
A correction unit that sequentially corrects the predetermined time in advance in preparation for the subsequent shift is provided.

The rotation speed of the input portion of the speed change gear mechanism may be, for example, the turbine rotation speed of the torque converter or the engine rotation speed.

(Effects of the Invention) As described above, according to the present invention, the engagement speed of the specific friction element is always optimized based on the change in the rotational speed of the input portion of the speed change gear mechanism, that is, the secular change or the individual difference It is possible to effectively prevent a shift shock by comprehensively compensating for an operating state at the time of shifting.

Embodiment An embodiment of the present invention will be described in detail below with reference to the drawings.

Gear Transmission Mechanism In FIG. 1, an automatic transmission is a torque converter 1
And a multi-stage gear transmission mechanism 2 and an overdrive planetary gear transmission mechanism 3 arranged between the torque converter 1 and the multi-stage gear transmission mechanism 2.

The torque converter 1 includes a pump impeller (hereinafter abbreviated as “pump”) 5 coupled to an engine output shaft 4.
A turbine runner (hereinafter abbreviated as “turbine”) 6 arranged to face the pump 5 and a stator 7 arranged between the pump 5 and the turbine 6 are provided. The shaft 8 is connected. Also,
A lockup clutch 9 is provided between the converter output shaft 8 and the pump 5. The lock-up clutch 9 is constantly urged in the engagement direction by the hydraulic oil pressure circulating in the torque converter 1, and is maintained in an open state by being supplied with an opening hydraulic pressure from the outside.

The multi-stage gear speed change mechanism 2 includes a front stage planetary gear mechanism 10 and a rear stage planetary gear mechanism 11, and the sun gear 12 of the front stage planetary gear mechanism 10 and the sun gear of the rear stage planetary gear mechanism 11 are connected by a connecting shaft 14. The input shaft 15 of the multistage gear speed change mechanism 2 is connected to the connecting shaft 14 via a front clutch 16.
In addition, through the rear clutch 17, the front planetary gear mechanism 1
0 internal gears 18 are respectively connected. A second brake 19 for selecting the second speed is provided between the connecting shaft 14, that is, the sun gears 12 and 13 and the transmission case C. The planetary carrier 20 of the front planetary gear mechanism 10 and the planetary carrier 21 of the rear planetary gear mechanism 11 are connected to the output shaft 22. A low / reverse brake 24 and a one-way clutch 25 are provided between the planetary carrier 23 of the rear planetary gear mechanism 11 and the transmission case C.

This multi-stage gear speed change mechanism has a conventionally known speed change mechanism, and has three forward speeds and one reverse speed, and includes a front clutch 16, a rear clutch 17, a second brake 19, and a low / reverse brake 24. As will be described later, it is possible to obtain a required gear by appropriately operating the hydraulic actuators.

The overdrive planetary gear transmission mechanism 3 includes a planetary carrier 27 that rotatably supports the planetary carrier 26, and a sun gear 29 that is coupled to an internal gear 30 via a direct clutch 29.
An overdrive brake 31 is provided between the sun gear 29 and the transmission case C, and the internal gear 30 is connected to the input shaft 15 of the multistage gear transmission mechanism 2.

This overdrive planetary gear speed change mechanism 3 has a converter output shaft 8 and an input shaft 1 when the direct clutch 29 is engaged and the overdrive brake 31 is released.
When the direct clutch 29 is disengaged and the direct drive clutch 29 is released, the converter output shaft 8 and the input shaft 15 are overdriven.

In this transmission, a manual valve of a hydraulic control circuit, which will be described later, is manually selected to operate each friction member (clutch and brake) of the multi-stage gear transmission mechanism 2 and the overdrive planetary gear transmission mechanism 3 as appropriate. By so doing, the required shift speed is obtained, and the control pattern of each friction member is set for each range as shown in the following Table 1 as in the conventional structure.

Hydraulic circuit The hydraulic circuit is the first circuit above depending on the driver's select operation.
Although it has a circuit configuration in which each friction member can be operated in the operation pattern as shown in the table to obtain a predetermined shift speed, only the portion particularly related to the present invention is shown in FIG. .

First, 101 is a first actuator, and the first actuator 101 is a hydraulic pump 50 as a hydraulic source.
Is urged by the hydraulic pressure supplied from the oil passage 111 to fasten the front clutch 16 as the first friction element. Further, 102 is a second actuator, and the second actuator 102 is biased by hydraulic pressure supplied via a branch passage 112 branched from the oil passage 111,
The engagement of the second brake 19 as the second friction element is released.

Reference numeral 103 denotes a 2-3 shift valve, which is configured to open the oil passage 111 at the first position and connect the oil passage 111 on the actuator 101 side and the hydraulic pressure discharge passage 113 at the second position. ing. A 3-2 timing valve 104 is installed in the branch passage 112,
The timing valve 104 opens the branch passage 112 in the first position and the actuator 102 in the second position.
The side branch path 112 and the hydraulic pressure discharge path 114 are configured to communicate with each other. A check valve 107 and a throttle 108 are connected to the branch passage 112 in parallel with each other between the timing valve 104 and the shift valve 103. The check valve 107 can only supply the hydraulic pressure from the shift valve 103 side to the second actuator 102 side.

Therefore, when the timing valve 104 is closed (at the first position), the shift valve 103 is switched to supply hydraulic pressure to both actuators 101 and 102, while the actuator 102, 102 is driven through the shift valve 103. The hydraulic pressure is released from 102. The hydraulic pressure released from the second actuator 102 through the shift valve 103 has the throttle 108,
It will be done slowly. On the other hand, when the timing valve 104 is opened (at the second position), the hydraulic pressure release from the second actuator 102 is promptly performed from the discharge passage 114 through the timing valve 104. In this way, the timing valve 1
04 and the diaphragm 108 constitute an opening speed adjusting means.

The 2-3 shift valve 103 is driven by a 2-3 shift solenoid valve 105, and the 3-2 timing valve 104 is a solenoid valve 1 for timing adjustment.
It is driven by 06.

FIG. 2 is a hydraulic circuit diagram specifically showing the relationship between the second brake 19, the second actuator 12, the timing valve 104, and the solenoid 106. First, the actuator 102 is defined by a piston 61 into two chambers, a first oil chamber 62 on the apply side and a release-side oil chamber 63, and the piston 61 is connected to the second brake 19. The oil pressure is constantly supplied to the oil chamber 62 on the apply side through the oil passage 116, and when the oil pressure is supplied to the oil chamber 63 on the release side, the piston 61 cooperates with the urging force of the spring 64. The second brake 19 is released by being displaced downward in the figure. On the contrary, when the oil pressure in the oil chamber 63 on the release side is released, the piston 61 is displaced upward in the figure and the second brake 19 is engaged. The aforementioned branch passage 112 is connected to the oil chamber 63 on the release side, and this branch passage 112 is closed (branch passage 112 and discharge passage) by the hydraulic pressure supply and hydraulic pressure release to the timing valve 104 by the solenoid 106. 114 is closed) or opened (112 and 114 are in communication).

The shift control 200 basically includes a CPU, a ROM, a RAM, and a CLOC.
The control circuit comprises a microcomputer equipped with K. This control circuit 200 operates in accordance with a predetermined control means on the basis of information indicating the operating state of the engine, which is provided by a rotation speed sensor 201, an engine load sensor (throttle opening sensor) 202, etc. Control movements. Then, the control circuit 200
-3 The shift signal A ₁ for switching the shift valve 103 to the second position is output to the solenoid valve 105, and 3
The timing signal A ₂ for switching the −2 timing valve 104 to the second position is output to the solenoid valve 106, and the output timing of both sides A ₁ and A ₂ will be described later.

FIG. 3 shows the control circuit 200 to the solenoid valve 105,
The waveforms of the shift signal A ₁ and the timing signal A ₂ that are respectively output to 104 are shown, and both signals A ₁ and A ₂ are turned off during the third speed running. The 2-3 shift valve 103 is at the first position and the oil passage 11 is
1 is open, hydraulic pressure is applied to the first actuator 101 to engage the front clutch 16, and
Since the 3-2 timing valve 104 is also at the first position and the oil passage 112 and the hydraulic pressure discharge passage 114 are closed, the hydraulic pressure is applied to the second actuator 102, and thus the second brake 19 is opened.

When shifting down from this state to the second speed, as shown in FIG. 3 (B), the shift signal A ₁ from the control circuit 200 is turned on, and the 2-3 shift solenoid valve 10 is turned on.
5, the 2-3 shift solenoid valve 103 is shifted to the second position (see FIG. 3D). As a result, the hydraulic pressure to the actuator 101 side decreases, and the front clutch 16 quickly shifts from the engaged state to the released state. At the same time when the shift signal A ₁ is turned on, the third signal
As shown in FIG. 6C, the timing signal A ₂ is turned on from the control circuit 200, and the timing valve 104 is displaced to the second position. As a result, the hydraulic pressure from the second actuator 102 is quickly supplied from the discharge passage 114. The timing signal A ₂ is turned on only for a predetermined time τ after the shift signal A ₁ is turned on, and when the predetermined time τ has elapsed, the timing signal A ₂ is turned on.
Is turned off again to set the timing valve 114 to the first position (see FIG. 3 (E)). As a result, the hydraulic pressure release from the second actuator 102 is performed more slowly than the discharge passage 113 via the throttle 108. In this way, the second brake 19 is rapidly displaced in the engagement direction during the predetermined time τ by turning on the timing signal A _{2 for} the predetermined time τ and turning it off after the predetermined time τ has passed, and the predetermined time τ. After the lapse of time, the fastening is done slowly and eventually the fastening is completed.

In the embodiment, the predetermined time τ is changed by using the vehicle speed as a parameter as shown in FIG. 5, but other than this, the turbine speed, the throttle opening, the rate of change of the throttle opening, etc. may be changed as parameters. May be.

Here, the determination of the end of the shift down from the third speed to the second speed is
This is done as follows. First, turbine speed TR
The EV is changed from the rotational speed ₃ at the time of traveling at the third speed to the rotational speed N ₂ at the time of traveling at the second speed. When the rate of change VTREV of the turbine speed at this time becomes 1/2 of the maximum value VREVM, the shift down is completed.

Further, the correction of the predetermined time τ under the shift condition (for example, vehicle speed) is performed based on the actual turbine rotation speed TREV at the time when the determination of the end of the downshift is made. This point will be described more specifically.
As shown in the figure, the time at which both the signals A ₁ and A ₂ are turned on is indicated by t ₁ (downshift flag 0 → 1),
Further, as described above, the time point (downshift flag 1 → 0) at which it is determined that the shift is completed is indicated by t ₂ . The actual turbine speed TREV at the time point t ₂ at which the gear shift end is determined is 4 points, the actual vehicle speed Vsp is the C point, and the predicted value for the second speed running based on the actual vehicle speed Vsp (corresponding to C point) The turbine speed TROVE is shown at point B. In this way, by obtaining the predicted turbine rotation speed TRAVE based on the actual vehicle speed Vsp after the shift end determination, the predicted turbine rotation speed TRAVE is accurately obtained without being affected by the difference in gear shift, for example, the accelerator pedal depression speed. be able to.

FIG. 9 shows another method of calculating the predicted turbine rotation speed TROVE at the time when it is determined that the shift is completed.
In FIG. 9, the predicted turbine speed TREV at the second speed is obtained based on the turbine speed at t ₁ at the start of gear shift or the engine speed. In this case, there is an advantage that a vehicle speed sensor is not required separately.

A value ΔT obtained by subtracting the expected turbine rotation speed TREE (point B) from the actual turbine rotation speed TEREV (point A) becomes the blowing-up amount of the turbine rotation speed, and the predetermined amount is based on the blowing-up amount ΔT. The time τ is corrected. In addition,
The blow-up amount can also be obtained from the difference between the actual engine speed and the expected engine speed.

The correction value Δτ for the predetermined time τ based on ΔT is set as shown in FIG. 7, for example. That is, the amount of blowing up △
The upper limit value α and the lower limit value β of T are set in advance as shown in FIG. 7 with the vehicle foot as a parameter, and if ΔT is equal to or greater than α, the amount of blowing up is too large, so the predetermined time τ is increased. If the amount of blow-up ΔT is equal to or less than β, it means that the amount of blow-up is too small. Therefore, the predetermined time τ is corrected to be smaller. In this correction, in order to minimize the influence of noise, the correction amount per time is set to "25 msec". By setting the correction amount per time as small as “25 msec”, the influence of noise is eliminated, and a situation in which τ is corrected to an inappropriate value including noise all at once is avoided. .

This ΔT (Δ
FIG. 8 schematically shows the correction based on τ).
FIG. 8 shows an example in which the predetermined amount τ is corrected in the direction of increasing it because the amount of blow-up ΔT is too large. That is, during the first shift from the third speed to the second speed, the predetermined time τ is set to, for example, “75 msec”, and the upstroke amount ΔT at this time is set to be considerably large (Δ
T ≧ α). Therefore, when shifting from the third speed to the second speed for the second time, the correction amount "2
It is set to "100 msec" by adding "5 msec".
At the time of the second shift, the amount of blow-up is reduced more than at the time of the first shift, but it is still a considerably large value (ΔT ≧ α). Therefore, when shifting from the third speed to the second speed for the third time, the predetermined time τ is set to the second predetermined time τ.
(= 100 msec), further correction amount "25 msec"
Is set to "125 msec". This allows
During the third shift from 3rd speed to 2nd speed, the amount of upstroke ΔT is further reduced. In this way, by correcting the predetermined time τ in accordance with the blowing amount ΔT, the optimum predetermined time τ that minimizes the shift shock is set. Of course,
When the blow-up amount ΔT is too small (ΔT ≦ β), contrary to the above case, the predetermined time τ is “25 mse per correction for one time”.
c ”is gradually decreased. The feedback control based on such a blowing amount ΔT is schematically shown in FIG. In FIG. 4, G indicates the magnitude of the shift shock as the acceleration acting in the front-rear direction of the vehicle body.

Details of Shift Control (Flowchart) A flowchart showing the control contents of the control circuit 200 described above will be described below. In the following description, S indicates a step.

First, initialization settings are made in S1 to S3. That is, all flags and timers are reset in S1,
The gear position of the multi-stage gear transmission 2 is set to the third speed in S2, and the turbine speed is measured for 125 milliseconds in S3.

Next, the flow shown in S4 to S12 is executed every 25 milliseconds. In S5, a mode switch (not shown) for gear shift characteristic selection and sensor measurement are performed, and in S6, range and mode (economy mode, power mode). ) Make a decision. In the next S7 and S8, a shift-up determination and a shift-down determination subroutine is executed (the sub-flow of the shift-down determination in S8 will be described later).
In S9, the output is output to the shift solenoid valve, and the next S10
Then, a subroutine for shift-up end determination and shift-down end determination is executed in S11 (a sub-flow for shift-down end determination in S11 will be described later). Then, in step S12, 3 for setting the drive timing τ of the 3-2 timing valve 104 in FIG.
-2 Execute the timer learning control subroutine and return to S4.

Next, the sub-flow of the downshift determination control in S8 of FIG. 10 will be described with reference to FIG. First, in S21, the gear position, that is, the gear position of the multi-stage gear transmission mechanism 2 is read, and it is determined whether or not the read gear position is the first speed. If this determination is YES, the control ends as it is.

On the other hand, when the gear position is not the first speed, that is, when the result is NO, the throttle opening degree output from the engine load sensor 202 is read in S22, and then the first opening is performed in S23.
The set turbine rotation speed Tspm on the map corresponding to the throttle opening is read out by collating with the shift line Ld of the shift down map of FIG. Then, in S24, the actual turbine rotation speed Tsp is obtained from the output of the turbine rotation speed sensor 201.
Is read and it is determined whether or not it is smaller than the set turbine rotation speed Tspm. When this determination is YES, it is determined in the next S26 whether or not the downshift flag is "1". The downshift flag is set to "1" when the downshift is executed, and the downshift state is stored. When the determination with respect to the down soft flag is YES, it is considered that the down shift is being performed, and the control is ended as it is.

Conversely, when the determination in S26 is NO, S2
After setting the downshift flag to "1" in step 7,
Thus, it is determined whether the shift is from "3rd speed to 2nd speed" or "4th speed to 2nd speed". NO in the determination in S28
In case of, the control is terminated as it is. On the contrary, when the determination in S28 is YES, the predetermined time τ in S29 is the time f (Vsp) read from the map shown in FIG. 5 based on the current vehicle speed Vsp and the shift condition (vehicle speed). After being set as a value obtained by adding the stored correction value Δτ (Vsp), the gear position of the multi-stage gear speed change mechanism 2 is downshifted by one step in S30 (signals A ₁ and A ₂ are turned on) and controlled. To finish.

Next, the sub-flow of the shift down end determination control in S11 of FIG. 10 will be described with reference to FIG.
First, in S31, it is determined whether or not the downshift flag is "1", and if the determination is NO, the control ends as it is. If the determination in S31 is YES, the program proceeds to S32 to calculate the turbine revolution change rate VTREV. And next S3
3, the maximum value of the turbine rotation change rate during gear shifting VTREV
After changing M, in S34, the turbine rotation change rate VTRE
It is determined whether V is smaller than VTREVM / 2. When this determination is NO, the control is terminated as it is, but when the engine is blown up, the turbine rotation change rate is VTREV <VTREV at the top of the turbine rotation.
It becomes M / 2. At this time, the process proceeds to S35 and the downshift flag is set to "0" to end the control.

The next FIG. 13 is to set the drive timing τ of the 3-2 timing valve 104 in S12 of FIG. 10 3-2
It is a sub-flow of timer learning control. First, step S4
At 1, it is determined whether or not downshifting from the third speed to the second speed or from the fourth speed to the second speed. And if this determination is YES,
Proceeding to S42, the predicted turbine rotation speed TRAVE is calculated from the turbine rotation speed and the gear ratio at the start of gear shifting. Thereafter, after the vehicle speed VSP is calculated in S44, it is determined in S45 whether or not it is immediately after the downshift flag is changed from 1 to 0. When the determination in S45 is NO, the control is terminated as it is. Conversely, S4
If the result of the determination in step 5 is YES, the process proceeds to S46, where the actual turbine speed TREV is changed to the predicted turbine speed TREV.
By subtracting E, the blowing amount ΔT is calculated.

After S46, it is determined in S47 whether or not ΔT is equal to or more than the upper limit value α. YE in the determination of S47
In the case of S, in S48, the correction value "25mses" per time is added to the previous correction value Δτ to obtain a new correction value Δτ. Thereafter, in S51, this Δτ is stored (updated) as the correction value Δτ (Vsp) under the shift condition (vehicle speed) of this shift. This correction value Δτ will be added to τ obtained from the map at the next shift at the same shift condition.

On the other hand, when the determination in S47 is NO, it is determined in S49 whether ΔT is less than or equal to the lower limit value β. If YES in the determination in S49, Δτ is set to “25 mse in S50.
c ”is corrected as the subtracted value, and then S51 described above is performed.
Is processed. If the determination in S49 is NO, Δτ does not need to be corrected, and in that case, S51.
Is processed.

The 14th is a reference value ΔT that predetermines the air-blown amount ΔT.
9 shows a modification of the 3-2 timer learning control (corresponding to S12 in FIG. 10) when the calculation is performed based on B. In FIG. 14, S61 to S64 are the first
Although it corresponds to the processing of S41 to S46 in FIG. 3, the vehicle speed Vsp is not used for the calculation of the correction value Δτ.
The process of S44 in FIG. 3 is not performed. S64 above
After the calculation of the blowing-up amount ΔT in step S65, a value obtained by multiplying the blowing-up amount ΔT by “25 msec” is set as a reference value Δ in S65.
The corrected Δτ is calculated by dividing by TB.
Then, the correction value Δτ in S66 is stored. In the case of the embodiment shown in FIG. 14, it is possible to set the predetermined time τ commensurate with the blowing amount ΔT at once by one correction.

Although the embodiment has been described above, the present invention is not limited to this, and includes the following cases, for example.

When the control circuit 200 is configured using a computer, it may be digital type or analog type.

As the speed change mechanism 2, an appropriately known one can be adopted.

The predetermined time τ shown in FIG. 5 may be corrected using an element such as the oil temperature that affects the shift shock as a parameter.

The correction value Δτ remains constant even after the ignition key is turned off.
It may be possible to use it from the next engine starting special feature. In this case, the correction value Δτ is stored in the nonvolatile memory (RA
It may be stored in M) or a separate backup power source may be used (the basic τ value is stored in ROM).

[Brief description of drawings]

FIG. 1 is an overall system diagram showing an embodiment of the present invention. FIG. 2 is a diagram showing a specific hydraulic circuit example of a second actuator portion. FIG. 3 is a graph showing the relationship between the shift signal, the timing signal, the shift valve, and the timing valve when shifting down from the third speed to the second speed. FIG. 4 is a diagram showing feedback control for correcting a predetermined time. FIG. 5 is a map showing basic set values for a predetermined time. FIG. 6 is a diagram showing an example of obtaining an expected turbine rotation speed at the time of determining the shift end. FIG. 7 is a diagram showing an example of a map used when determining a correction value for a predetermined time. FIG. 8 is a diagram schematically showing how shift shock is reduced by the present invention. FIG. 9 is a diagram showing another example of obtaining the expected turbine rotation speed at the time of determining the end of gear shift. 10 to 14 are flowcharts showing a control example according to the present invention. FIG. 15 is a diagram showing an example of shift characteristics (only for downshifting). FIG. 16 and FIG. 17 are diagrams showing the rotational state of the turbine rotational speed when a large shift shock occurs. FIG. 18 is an overall configuration diagram of the present invention. 2: Gear transmission mechanism 8: Turbine shaft 15: Input shaft 16: Flot clutch (first friction element) 19: Second brake (second friction element) 101: First actuator 102: Second actuator 103: 2-3 shift Valve 104: 3-2 Timing valve (opening speed adjusting means) 108: Aperture (opening speed adjusting means) 105, 106: Solenoid 200: Control circuit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kazuo Shinide, No. 3 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Mazda Co., Ltd. (72) Hiroaki Yokota, No. 3 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Stock In-company (72) Inventor Keizo Yanagisawa 3-2 Yodabashi-cho, Fuji-shi, Shizuoka Prefecture (72) Inventor Hokuto Takeuchi 23-7 Nishi-machi, Fujinomiya-shi, Shizuoka Prefecture

Claims (1)

[Claims] 1. An automatic transmission having a plurality of friction elements, and a transmission gear mechanism for switching a power transmission path to a plurality of stages by engaging and releasing operations of the friction elements, wherein a specific friction of the transmission gear mechanism is provided. An engagement speed adjusting means for adjusting an engagement speed of the element, and the engagement so as to increase an engagement speed of the specific friction element to be engaged for a predetermined time at the time of a gear shift when the power transmission path is switched by the speed change gear mechanism. The engagement speed control means for controlling the speed adjusting means, the rotation speed detection means for detecting the rotation speed of the input portion of the speed change gear mechanism, and the speed change gear mechanism at the time of the current speed change, receiving the output of the rotation speed detection means. Depending on the change of the rotation speed of the input part of
A shift control device for an automatic transmission, comprising: a correction unit that sequentially corrects the predetermined time in advance in preparation for a subsequent shift.