JPH11141675A - Shift control device for automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accomplish a stable shift control by stabilizing the slip starting point regardless of the situation of an engaging element such as a clutch, for example deterioration with time, enhance the durability by suppressing the slip of the engaging element to a specified extent and shortening the control period of the current shift range, and establish changing-over to the next step control in smooth continuity. SOLUTION: At the first step as the initial period of the control in the current shift range, a feedback control is made so that the clutching, etc., in the current range becomes the first target slippage ECL02 (S10-S24). Then the operation proceeds to the second step as the subsequent period, and a feedback control is made so that the clutching, etc., in the current range becomes the second target slippage ECL02, and the oil pressure command signal (supply oil pressure decremental torque command value QTRQ) is corrected in accordance with the deviation of the actual slippage from the second target slippage (S26-S34), and the next time oil pressure command signal is determined on the basis of the corrected value (S36).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shift control device for an automatic transmission, and more particularly, to an automatic shift control device for a vehicle which appropriately controls an operating oil pressure supplied to a current-stage (previous-stage) engagement element during an upshift. The present invention relates to a shift control device for a transmission.

[0002]

2. Description of the Related Art An automatic transmission is provided with a plurality of gear trains, and a plurality of power transmission paths formed by the gear trains are selectively engaged with engagement elements such as clutches and brakes to control input rotation. Shift the gears. Such an automatic transmission releases the current-stage (previous stage) power transmission path setting engagement element and engages the next-stage (destination stage) power transmission path setting engagement element to shift gears. I do.

[0003] In order to shift the gears smoothly and without a time lag, the disengagement or engagement timing of the current-stage and next-stage engagement elements is set accurately, and the release of the current-stage and next-stage engagement elements is completely stopped. It is necessary to appropriately perform control up to engagement. For that purpose, for example,
Japanese Patent Application Laid-Open No. 2-24653 proposes a method of reducing the operating oil pressure of a current stage engaging element and absorbing the inertia by slip control after a shift command is issued.

[0004] However, according to the method proposed in the prior art, it is difficult to detect at what point the current stage clutch has begun to slip. Accordingly, the present applicant also discloses Japanese Patent Application Laid-Open No. 6-307524 or Japanese Patent Application Laid-Open No. 8-277921.
In Japanese Patent Application Laid-Open Publication No. H10-163, the control period of the current stage is divided into several steps, the operating oil pressure supplied to the current stage clutch is reduced, and then the slip (slip) of the clutch is feedback-controlled based on the throttle opening and engine torque. Propose technology.

[0005]

However, the slip state changes depending on the state of the current stage clutch, for example, aging, plate temperature or shift state, and the slip start point changes even when the hydraulic pressure is controlled to the target value. . Also, when the current-stage clutch starts slipping due to pressure reduction, the friction state of the clutch changes, so it is necessary to slightly increase the average oil pressure.However, at this time, the clutch slip is kept within a predetermined range to shorten the current-stage control period. If this can be done, the durability of the clutch is improved, and the control can be smoothly continued to the next stage control.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to realize a stable shift control by stabilizing a slip starting point regardless of a change such as deterioration with time of an engagement element such as a clutch, and to realize a stable shift control. Is provided within a predetermined range, thereby shortening the control period of the current stage, thereby improving the durability of the engagement element, and further allowing the control to be smoothly continued to the next stage control. Is to do.

[0007]

In order to achieve the above object, according to the present invention, a plurality of power transmission paths formed between input and output members and the power transmission path are selectively provided. A plurality of engagement elements to be set, and engagement control means for controlling an engagement hydraulic pressure of the engagement elements in accordance with a hydraulic pressure command signal. In the shift control device of the automatic transmission, the operating oil pressure of the current-stage engaging element is reduced and released while performing slip control, and the next-stage engaging element is engaged to shift up from the current stage to the next stage. A first step of determining a hydraulic pressure command signal so that the current stage engagement element has a first target slip ratio, and a second step of performing feedback control so that the slip ratio of the current stage engagement element has a second target slip ratio. Steps, and said A hydraulic command for detecting a maximum value of the actual slip ratio of the engagement element in one step, and correcting a hydraulic command signal in the first step at the next shift-up according to the detected slip ratio and a second target slip ratio. A signal correction unit and a next hydraulic command signal determining unit for determining a next hydraulic command signal based on the corrected hydraulic command signal are provided.

Thus, regardless of the state of the engagement element such as deterioration with time of the engagement element such as a clutch, the slip start point is stabilized, thereby realizing a stable shift control and realizing the slip of the engagement element. To a predetermined range, the control period of the current stage can be shortened, the durability thereof can be improved, and the control of the next stage can be smoothly continued.

According to another aspect of the present invention, the hydraulic command value in the second step is determined to be larger than the hydraulic command value in the first step.

Thus, in addition to the above-mentioned effects,
Shift control that is stable with respect to a change in the frictional state of an engagement element such as a clutch can be realized.

[0011]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a schematic explanatory view showing the configuration of a control device for an automatic transmission according to the present invention.

The automatic transmission 1 includes a torque converter 8, which is connected to an output shaft 9 of an internal combustion engine 9a. Turbine of torque converter 8 (not shown)
Is connected to the transmission input shaft 8a.

The automatic transmission 1 includes first, second and third planetary gear trains G1, G1 arranged in parallel on a transmission input shaft 8a.
G2 and G3. Each of the planetary gear trains includes first, second, and third sun gears S1, S2, and S3 located at the center, respectively.
First, second, and third planetary pinions P1, P2, and P3 that mesh with the first, second, and third sun gears and revolve while rotating around them, and a pinion that rotatably holds the pinions. , Second, and third carriers C1, C2, and C3 that rotate the same as the revolution of the first and second, third, and third ring gears R having internal teeth that mesh with the pinions.
1, R2 and R3.

The first planetary gear train G1 and the second planetary gear train G2 are double pinion type planetary gear trains, and the first pinion P1 and the second pinion P2 have two pinion gears P11 and P12, respectively, as shown in the figure. , P21, P2
And 2.

The first sun gear S1 is always connected to the input shaft, and the first carrier C1 is always fixed. The first ring gear R1 is connected to a second sun gear S2 via a third clutch K3, and the second sun gear S2 is connected to a first brake B1.
Can be fixedly held. The second carrier C2 is the third
While being connected to the carrier C3, it is also connected to the output gear 8b, and the rotation of the second carrier C2 and the third carrier C3 becomes the output rotation of the transmission.

The second ring gear R2 is connected to a third ring gear R3.
These two ring gears R2, R3 are integrally fixed and held by a second brake B2, and are connected to a transmission input shaft via a second clutch K2 so as to be freely engaged and disengaged. The third sun gear S3 is detachably connected to the transmission input shaft via a first clutch K1. One-way clutch OWC is arranged in parallel with second brake B2.

As described above, each element (first to third sun gears S)
1 to S3, first to third carriers C1 to C3, and first
To the third ring gears R1 to R3), the transmission input shaft 8a and the output gear 8b, the first to third clutches K1 to K3 and the first and second brakes B1 and B2. By performing the de-control, it is possible to set the shift speed and perform the shift control.

More specifically, if the engagement / disengagement control is performed as shown in Table 1, the forward 5th speed, ie, 1ST (1st speed), 2ND (2nd speed)
Speed), 3RD (3rd speed), 4TH (4th speed) and 5TH
(5th speed) and a reverse speed (RVS) can be set. Note that the reduction ratio (ratio) at each shift speed changes depending on the number of teeth of each gear, and Table 1 shows an example of the change.

[0020]

[Table 1]

In Table 1, the second brake B2 in 1ST (first speed) is indicated in parentheses. This means that the one-way clutch CO can be operated without engaging the second brake B2.
This is because power is transmitted on the driving side by W. That is, if the first clutch K1 is engaged, the second brake B
Even when the second gear 2 is not engaged, power transmission on the driving side can be performed at the gear ratio (speed ratio) of 1ST, and 1ST is set.

However, power cannot be transmitted in the reverse direction to the drive side. Therefore, when the second brake B2 is engaged, the engine brake is effective 1ST. When the second brake B2 is disengaged, the engine brake is not engaged. Is not effective.

In order to control the supply of hydraulic pressure to the friction engagement element, a controller 200 including a microcomputer is provided.

Further, in the vicinity of the transmission input shaft 8a, similarly to the rotation speed sensor 202 comprising a magnetic pickup, similarly, in the vicinity of the output gear 8b, the transmission output rotation speed is arranged, and the transmission input rotation speed is determined. In addition to outputting a signal proportional to Nin, a rotation speed sensor 204 similarly including a magnetic pickup is disposed near the output gear 8b to output a signal proportional to the transmission output rotation speed Nout.

A range selector switch 206 is connected to the shift lever 208 near the driver's seat, and outputs a signal corresponding to the gear range selected by the driver.

Further, a crank angle sensor 210 is arranged near a crankshaft (not shown) of the internal combustion engine 9a to output a signal proportional to the engine speed NE, and to a throttle valve (not shown). Throttle position sensor 212
And outputs a signal proportional to the throttle opening θTH (engine load).

A vehicle speed sensor 214 is arranged near a drive shaft (not shown) of the vehicle, and outputs a signal proportional to a vehicle speed V which is a traveling speed of the vehicle on which the automatic transmission 1 is mounted.

The outputs of these sensors are sent to the controller 20
Input to 0.

Based on the detected parameters, the controller 200 excites (energizes or turns on) or deenergizes (deenerges or turns off) the solenoid valves SA to SE.
It controls the supply of hydraulic pressure to engagement elements such as the third clutches K1, K2, K3 and the first and second brakes B1, B2.
In the hydraulic control circuit 300, the hydraulic pressure is determined by five hydraulic sensors P
It is detected via S (described later), and the detected value is also sent to the controller 200.

Next, a hydraulic control circuit 300 for controlling the engagement and disengagement of the engagement elements will be described with reference to FIGS. FIGS. 2 and 3 show the respective components of the hydraulic control circuit, and these two figures constitute one hydraulic control device.

Each of the oil paths in each figure with a circled letter at the end indicates that the oil path is connected to the oil path with the same circled letter in the other figure. Also, ×
The mark indicates that the port opens to drain.

The operation control of the brakes and clutches is performed using the hydraulic pressure of hydraulic oil supplied from the tank shown in the lower part of FIG. 2 by the pump 10 (hydraulic power source). The high-pressure hydraulic oil discharged from the pump 10 to the oil passage 12 is adjusted to a predetermined line pressure by the regulator valve 14.

A part of the discharge oil from the pump 10 is sent out from the regulator valve 14 to the oil passage 16 and supplied for lock-up control of the torque converter. The hydraulic oil sent to the oil passage 18 is returned to the tank via a relief valve (not shown).

The oil passage 12 regulated to the line pressure as described above
Is supplied to corresponding parts for speed change control. The hydraulic circuit includes a manual valve 20 that is manually operated by a driver via a shift lever 208, and five shift solenoid valves SA to SE whose duty ratios are controlled by a controller 200 that detects the manual operation. Six hydraulically actuated valves 22, 24, 26, 2 which operate in accordance with the operation of the manual valve 20 and the shift solenoid valves SA to SE.
8, 30, 32 and four accumulators 34, 36,
38 and 40 and five hydraulic pressure sensors PS are provided.

The solenoid valves SA and SC are normally open type valves, and are opened when the solenoid is off. On the other hand, the solenoid valves SB, S
D and SE are normally closed type valves, and are closed when the power to the solenoid is turned off.

The valves 20, SA to SE, 22,
The shift control and the operation control of the lock-up clutch of the torque converter are performed by the supply control of the hydraulic oil by the control units 24, 26, 28, 30, and 32. The operation of each of the solenoid valves SA to SE and the setting thereof are set. The relationship with the speed stage is as shown in Table 2. Note that ON / OFF in Table 2 indicates ON / OFF of the electromagnetic solenoid provided in each of the solenoid valves SA to SE. When on, duty ratio control is performed.

[0037]

[Table 2]

The shift control will be described below. First, the case where the D range is selected by the shift lever and the spool 20a of the manual valve 20 moves to the D position will be described. In FIG. 3, the right end hook portion of the spool 20a is moved rightward to a position indicated by D (3, 2), and
When a is at the D position, the oil passage 12 to which the hydraulic oil adjusted to the line pressure is supplied communicates with the oil passage 42.

Since the oil passage 12 is connected to the solenoid valve SC and the oil passage 42 is connected to the solenoid valve SE, the solenoid valve SC and the solenoid valve S are connected.
The line pressure always acts on E. Further, since the oil passage 42 is also connected to the solenoid valve SA, the line pressure always acts on the solenoid valve SA. In this specification, directions such as right and left and up and down are used to indicate directions in the attached drawings.

The oil passage 12a branched from the oil passage 12 branches to the right end oil chamber of the reverse pressure switching valve 22, the oil passage 12b branched from the oil passage 12 branches to the left end oil chamber of the pressure release valve 24, and the oil passage 42. Oilway 42
a is connected to the right end oil chamber of the out-gear control valve 26, respectively. Therefore, the reverse pressure switching valve 22 and the out-gear control valve 26 are constantly pressed to the left, and the pressure release valve 24 is constantly pressed to the right by line pressure.

When the D range is selected, the shift speed is determined in accordance with the engine load (throttle opening θTH) and the vehicle speed V, and each solenoid valve S is set to the shift speed.
The operations of A to SE are controlled as shown in Table 2.

The operation of the clutch and the brake will be described below by taking as an example the case where the third speed (3RD) is set. In this case, the solenoid valve SC
And SD are switched from on to off, and all solenoid valves are turned off. As a result, from the state of the second speed (2ND), the solenoid valve SC is opened and the solenoid valve SD is closed. Since the solenoid valve SA is open, the first clutch K1 remains engaged. Since the solenoid valve SD is closed, the oil passage 54 communicates with the drain via the inside of the solenoid valve SD, and thus the first brake B1 is released.

On the other hand, when the solenoid valve SC is opened, the line pressure is supplied to the oil passage 52, and the third clutch K3 communicating therewith is engaged. At this time, the shock is reduced by the operation of the fourth accumulator 40. Thus, the first clutch K1 and the third clutch K3 are engaged, and the third speed (3RD) is set.

In the third speed (3RD), the solenoid valve SD is closed, and the oil pressure acting on the left end of the pressure delivery valve 28 via the oil passage 54 and the oil passage 54b also becomes zero. However, the rightward movement of the spool 28a is maintained by the operating oil pressure supplied through the oil passage 78. Therefore, when the solenoid valve SE is turned on as in the case of the second speed (2ND), the lockup clutch can be controlled by the output pressure.

As described above, the clutch and brake are disengaged and the shift is performed. Hereinafter, the operation of the shift control device according to the present invention will be described as upshifting, more specifically, when the throttle opening is equal to or more than a predetermined value. A description will be given of a power-on shift-up performed in the case of (1) as an example.

FIG. 4 is a subroutine flowchart showing the control, which is a process performed by the controller 200.

First, in S10, it is determined whether or not a shift command, more specifically, a shift-up command, for example, a shift-up command from the second speed to the third speed, has been issued. Solenoid valve SE
From on to off and release the lock-up clutch.

Then, the program proceeds to S14, in which a predetermined value T1 is set in a timer (down counter) to start counting down (time measurement), and the program proceeds to S16, where it is determined whether or not the predetermined time T1 has elapsed. The predetermined time T1 is set by obtaining a time enough to completely release the lock-up clutch before entering the clutch supply hydraulic pressure control.

If it is determined in step S16 that the predetermined time T1 has elapsed, the flow advances to step S18 to set the control period to step 1 (S
TEP1) and the processing JOB is JOBE.

FIG. 5 is a time chart showing the operation of FIG. 4. As shown in FIG.
The initial stage of the control from the time when the time has elapsed is defined as step 1,
The work there is JOBE.

Next, the program proceeds to S20, in which the current stage supply hydraulic pressure reduction torque value QTRQ is determined (calculated). FIG. 6 is a subroutine flowchart showing the operation.

First, in step S100, the initial value QTRQ of the reduced torque value QTRQ for supply hydraulic pressure at the current stage is set.
0 is calculated as follows. QTRQ0 = RESLOPE × TTRQABS + REC
ONTACT + CR

Here, RESLOPE: operation coefficient, TT
RQABS: Basic value according to engine torque (Table not shown indicates engine speed NE and intake pipe absolute pressure PBA
(Determined by searching from an absolute pressure sensor (not shown)), RECONTACT: added value for each gear, CR:
This is a throttle opening correction term.

Reduction torque value QTRQ for supply hydraulic pressure at current stage
Is the actual clutch slip ratio eCLO in step 1.
The calculation is performed in accordance with the engine torque so that a target clutch slip ratio (hereinafter referred to as “first target slip ratio”) ECLO2 (described below) becomes a target clutch slip ratio (described below).

More specifically, if it is the first program loop, the initial value QTRQ0 of QTRQ is calculated from the above equation, and if it is the second or subsequent loop, the previously calculated supply oil pressure reduction torque value QTRQ0 is calculated. Is kept as it is. It should be noted that the supply oil pressure reducing torque value QTRQ0 is more specifically the duty ratio (PW
M control).

Then, the program proceeds to S102, in which it is determined whether or not the current gear (gear) So exceeds the next gear (target gear or destination gear) SA. When the upshift is performed as in the illustrated example, the determination in S102 is denied, and the process proceeds to S104.
A map showing the characteristics in FIG. 7 is retrieved from the vehicle speed V to find a shift-up vehicle speed correction term QTRQu, and the routine proceeds to S106, where the correction term QT found for the supply oil pressure reduction torque value QTRQ is obtained.
The increase is corrected by adding RQu.

On the other hand, when the result in S102 is affirmative, in other words, when it is determined that the vehicle is downshifted, the routine proceeds to S108, in which a map showing the characteristic shown in FIG. Then, the vehicle speed correction term QTRQd is subtracted from the supply hydraulic pressure reduction torque value QTRQ to perform a decrease correction.

Returning to the description of the flow chart of FIG. 4, the program then proceeds to S22 in which the actual clutch slip ratio eCLO in step 1 is detected (calculated) as follows. eCLO = (Nout / Nin) × i where Nout = transmission output shaft rotation speed (output gear 8b
, Nin: the rotation speed of the transmission input shaft 8a, i:
Ratio (speed change ratio).

Next, the program proceeds to S24, where the detected (calculated) clutch slip rate eCLO is the target clutch slip rate (first target slip rate) EC in step 1 described above.
It is determined whether or not it has become less than LO2. Specifically, it is determined whether or not the current gear clutch is slipping by the target amount. FIG. 5 shows the first target slip ratio ECLO2. The first target slip ratio ECLO2 is appropriately set for each state of the engine and each shift speed.

When the result in S24 is negative, the process returns to S18 to repeat the above-described processing. When the result is affirmative, the process proceeds to S26, where step 1 is completed and step 2 (STEP 2).
Is determined to have started, and the work in step 2
OBF.

Then, the program proceeds to S28, in which the maximum value ECLO of the actual clutch slip ratio eCLO of the current stage in the first step is obtained.
R, and the process proceeds to S30, where the detected maximum value ECLOR
Based on the target slip ratio ECLO2 in step 1 and the target clutch slip ratio in step 2 (referred to as "second target slip ratio") ECLOref, as shown in the figure. That is, the average value of the maximum actual slip rate and the target slip rate in step 1 is obtained, and the average value is set as the target step rate in step 2.

Next, the process proceeds to S32, where the calculated second target slip ratio ECLOref is calculated as follows (step 1).
Deviation EC of the maximum actual clutch slip ratio ECLOR)
LOdif is obtained as an absolute value. ECLOdif = | ECLOref-ECLOR |

Then, a table showing the characteristics in FIG. 9 is searched from the obtained deviation to obtain a correction value QTRQα.

Then, the process proceeds to S34, in which the calculated correction value QTR is obtained.
Qα is added and the supply hydraulic pressure reduction torque value QTRQ is increased and corrected, and the supply hydraulic pressure reduction torque value QTRQ in step 2 is increased.
And That is, the oil pressure command value (supply oil pressure reduction torque value QTRQ) in step 2 is determined to be larger than the oil pressure command value (supply oil pressure reduction torque value QTRQ) in the first step. As a result, it is possible to realize a stable shift control with respect to a change in the frictional state of the engagement element such as the clutch.

Subsequently, the flow advances to S36 to store the obtained QTRQ.

Then, the program proceeds to S38, in which the supply oil pressure reduction torque value QTRQ obtained as described above is corrected. FIG. 10 is a subroutine flowchart showing the operation.

Referring to FIG. 10, first, in S200, the actual clutch slip ratio eCLO is subtracted from the OWC control target slip ratio appropriately set, and the difference, that is, the current slip ratio deviation ECLN is calculated. Then the calculated deviation E
Target deviation SECLO using CLN and coefficient KDNT
Is calculated from the following equation. SECLO = ECLN × KDNT / 100

Then, the program proceeds to S202, in which the actual clutch slip ratio eCLO is changed (first order differential value or differential value) S
eCLO is calculated, and it is determined whether or not the target deviation SECLO is equal to or greater than the change. The target deviation SECLO is changed SeCLO
If it is determined that the above is the case, the process proceeds to S204, in which the predetermined value TRQowc is subtracted from the supply hydraulic pressure reducing torque value QTRQ to correct the decrease, and the target deviation SECLO is changed by the change amount Se.
If it is determined that the value is less than the CLO, the process proceeds to S206, in which the predetermined value TRQowc is added to the supply hydraulic pressure reduction torque value QTRQ to increase and correct the increase.

Then, the program proceeds to S208, in which it is determined whether or not the target deviation SECLO is equal to or greater than an upper limit value SECLMAX.
If affirmative, the process proceeds to S210, where the target deviation SECLO
Is replaced with the upper limit value SECLMAX, and if the result is negative, S210 is skipped.

Returning to the description of FIG. 4, the program then proceeds to S40, in which it is determined whether the JOBF has been completed. Specifically, the next-stage clutch slip ratio is detected and is detected by a predetermined value ECLOa.
The judgment is made as to whether or not 1 has been exceeded. When the result in S40 is negative, the process returns to S28 to repeat the above processing. When the result is affirmative, step 2 ends, and it is determined that JOBF has ended, and the program ends.

As shown in FIG. 5, when the slip ratio of the next-stage clutch reaches a predetermined value ECLOa1, in other words, when the engagement of the next-stage clutch reaches a sufficient value, the current-stage clutch is released.

Incidentally, in the shift control after the next time, JO
In BE (Step 1), the current stage supply hydraulic pressure reduction torque value QTRQ is determined based on the supply hydraulic pressure reduction torque value QTRQ stored in JOBF (Step 2) as described above.

Further, since the value of the friction coefficient of the clutch of the current stage engagement element decreases with the start of slipping of the clutch and causes excessive slipping of the clutch and the like, JOBF
Then, the actual clutch slip ratio is detected, and based on the deviation between the detected value and the second target slip ratio, the current hydraulic pressure reduction torque value QTRQ for the current stage is corrected (S34 in FIG. 4). Therefore, JO
Reduced torque value QTRQ for supply hydraulic pressure in BF (step 2)
Is set to a value larger than that of JOBF (step 1).

Here, a description will be given in accordance with the expression of the claims. In this embodiment, a plurality of power transmission paths formed between input / output members and the power transmission paths are selectively set. A plurality of engagement elements, and engagement control means for controlling an engagement operating oil pressure of the engagement elements in accordance with a hydraulic command signal, and based on a predetermined shift-up signal, the plurality of engagement elements In the shift control device of the automatic transmission, the operating oil pressure of the current stage engaging element is reduced to release the slip while performing the slip control, and the next stage engaging element is engaged to shift up from the current stage to the next stage. The hydraulic command signal (QTRQ) is determined so that the current stage engagement element becomes the first target slip ratio (ECLO2) (S2 in FIG. 4).
0, S100 to S110 in FIG. 6) First step, feedback control so that the slip ratio of the current stage engagement element becomes the second target slip ratio (ECLOref) (S30 in FIG. 4), the second step, and In the first step, the maximum value (E
CLOR), and a hydraulic command signal correcting means (S30, S30) for correcting the hydraulic command signal in the first step at the next shift up according to the difference (ECLOdef) between the detected slip rate and the second target slip rate. S32) and a next hydraulic command signal determining means (S3) for determining the next hydraulic command signal based on the corrected hydraulic command signal.
6).

The hydraulic command value in the second step is determined to be larger than the hydraulic command value in the first step (S3).
4) It was constituted as follows.

In this embodiment, as described above, step 2
Since the supply oil pressure determined in (JOBF) is used as the supply oil pressure in step 1 (JOBE) at the time of the next upshift,
The slip of the clutch does not become excessive when the current stage clutch is depressurized, the durability of the clutch and the wear material can be improved, and the control can be smoothly shifted to the next stage clutch supply hydraulic pressure control.

Further, by reducing the oil pressure supplied to the current stage clutch, it is possible to realize a stable feedback control with respect to a change in the friction coefficient when the clutch starts to slip.

Further, in order to set the hydraulic command value in the second step larger than the hydraulic command value in the first step,
It is possible to realize a stable slip control and, consequently, a shift control with respect to a change in the clutch plate temperature and a change in the oil temperature, that is, a change in the friction coefficient of the clutch.

In the above description, a planetary type automatic transmission is taken as an example, but a parallel shaft type automatic transmission as disclosed in Japanese Patent Application Laid-Open No. 8-184367 may be used.

[0080]

According to the first aspect of the present invention, the slip starting point is stabilized regardless of the state of the engagement element such as the deterioration of the engagement element such as the clutch with the passage of time, thereby realizing stable shift control. At the same time, the slip of the engagement element is suppressed within a predetermined range to shorten the control period of the current stage, thereby improving its durability and allowing the next stage control to be smoothly continued.

According to the second aspect, in addition to the above-described functions and effects, it is possible to realize a shift control that is stable with respect to a change in the frictional state of an engagement element such as a clutch.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory diagram showing a configuration of a control device for an automatic transmission according to the present invention.

FIG. 2 is a partial hydraulic circuit diagram of the control device of FIG. 1;

FIG. 3 is a partial hydraulic circuit diagram similar to FIG. 2;

FIG. 4 is a flowchart showing an operation of the control device shown in FIG. 1;

FIG. 5 is a time chart for explaining the operation of the flow chart of FIG. 4;

FIG. 6 is a subroutine flowchart showing a calculation operation of a reduced torque value for supply hydraulic pressure QTRQ in the flowchart of FIG. 4;

FIG. 7 is a correction term QTR used in the flowchart of FIG. 6;
It is an explanatory graph which shows the table characteristic of Qu.

FIG. 8 is a correction term QTR used in the flow chart of FIG. 6;
It is explanatory drawing which shows the table characteristic of Qd.

FIG. 9 is a correction value QTR used in the flowchart of FIG. 4;
It is an explanatory graph showing a table characteristic of Qα.

FIG. 10 is a subroutine flowchart showing a correction operation of the supply oil pressure reduction torque value QTRQ in the flowchart of FIG. 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Automatic transmission 8 Torque converter 8a Transmission input shaft 9 Engine output shaft 10 Pump PS Hydraulic sensor SA, SB, SC, SD, SE Solenoid valve K1, K2, K3 Clutch (engagement element) BR1, BR2 Brake (engagement) Element) 20 Manual valve 22, 24, 26, 28, 30, 96 Hydraulically operated valve 34, 36, 38, 40 Accumulator 200 Controller

Claims (2)

[Claims] A plurality of power transmission paths formed between input / output members; a plurality of engagement elements for selectively setting the power transmission paths; Engagement control means for performing control in accordance with a shift-up signal to lower the operating oil pressure of a preceding-stage engagement element of the plurality of engagement elements to release the same while performing slip control and to release the next-stage engagement element. A shift control device for an automatic transmission for shifting up from a current stage to a next stage by engaging a mating element, comprising: a. A first step of determining a hydraulic pressure command signal so that the current stage engagement element has a first target slip ratio; b. A second step of performing feedback control so that a slip ratio of the current stage engagement element becomes a second target slip ratio; c. A hydraulic command signal for detecting an actual slip rate of the current stage engagement element in the first step and correcting the hydraulic command signal of the first step in accordance with a difference between the detected slip rate and the second target slip rate; Correction means; and d. A shift control device for an automatic transmission, comprising: a next-stage hydraulic command signal determination unit that determines a next-stage hydraulic command signal based on the corrected hydraulic command signal. 2. The shift control device for an automatic transmission according to claim 1, wherein the hydraulic command value in the second step is determined to be larger than the hydraulic command value in the first step.