JPH1163192A - Controller for automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce shocks at the time of fastening by performing control so as to set the size of working pressure supplied to a hastening room smaller when the remaining amount of a hydraulic oil in an open room is small than that when the remaining amount of the hydraulic oil in the open room is large at the time of fastening a friction fastening element. SOLUTION: By supplying working pressure through an oil route (servo release line) 62 communicated with an open room 45e, a servo piston 45c pulls a piston rod 45f against pressure in a fastening room 45d side, and thereby a brake band 45g is unfastened again to release to 2-4 brake 45. If the remaining amount of a hydraulic oil in the open room is small at the time of fastening a friction fastening element, the working pressure supplied to the fastening room is controlled to be relatively small, and thus the sudden fastening of the friction fastening element is prevented and shocks at the time of fastening are reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an automatic transmission, and more particularly to a control device for an automatic transmission having a frictional fastening element having a fastening chamber and a release chamber as a hydraulic chamber.

[0002]

2. Description of the Related Art Generally, an automatic transmission mounted on an automobile combines a torque converter and a transmission mechanism, and switches a power transmission path of the transmission mechanism by selectively operating a plurality of frictional engagement elements such as clutches and brakes. The automatic transmission of this type is provided with a hydraulic control circuit for controlling the supply and discharge of the operating pressure to the hydraulic actuator of each of the frictional engagement elements. Can be The hydraulic control circuit includes, for example, a regulator valve that adjusts the discharge pressure of an oil pump to a predetermined line pressure, a manual valve that switches a gear position by manual operation, and switches an operating pressure for each of the actuators according to an operation state. Accordingly, a plurality of shift valves or the like for selectively operating the friction engagement elements are provided.

Incidentally, this type of automatic transmission has a fastening chamber and a release chamber as hydraulic chambers to which working pressure is supplied to both sides of a servo piston constituting a hydraulic actuator, and the operating pressure is applied only to the fastening chamber. A friction fastening element configured to be fastened when supplied and to be released when both hydraulic chambers are supplied with operating pressure and when both hydraulic chambers are not supplied with operating pressure. is there. For example, Japanese Patent Laying-Open No. 4-60261 discloses a 2-4 brake that is engaged at a second speed and a fourth speed as this kind of frictional engagement element.

In the 2-4 brake, for example, at the first speed immediately after the start in the D range, the operating pressure is not supplied to both hydraulic chambers and the released state is maintained, and at the time of shifting from the first speed to the second speed, By supplying the operating pressure only to the fastening chamber, the servo piston operates and the brake is engaged, so that the second speed is obtained. When shifting from the second speed to the third speed, the operating pressure is supplied to the release chamber of the 2-4 brake to release the brake, and at the same time, the frictional engagement element (3) engaged at the third and fourth speeds -4 clutch), the operating pressure is supplied to the hydraulic chamber, whereby the clutch is engaged and 3
Speed is obtained. Also, when shifting from third gear to fourth gear,
When the operating pressure is discharged from the release chamber of the 2-4 brake in a state where the -4 clutch is engaged, the brake is engaged and the fourth speed is obtained.

[0005]

In the prior art described in the above publication, there is a problem that a large shock is generated at the time of shifting from the first speed to the second speed in the early stage of the running of the vehicle after the engine is stopped. .

That is, in this type of automatic transmission, an oil pump that generates a working pressure supplied to each friction engagement element (hydraulic actuator) is driven by an engine. Therefore, when the engine is stopped for a long time, the hydraulic oil gradually escapes from the oil passages leading to the respective friction engagement elements, and accordingly, the remaining amount of the hydraulic oil in each hydraulic chamber decreases, and finally the empty state is obtained. Become. In this state, if the vehicle is started with the select lever set to the D range, the shift speed shifts from the first gear immediately after the start of traveling to the second gear as the vehicle speed increases.
The operating pressure is supplied to the brake engagement chamber. In this case, at the time of the 1-2 shift at the beginning of traveling,
-4 Since the oil passage leading to the release chamber of the brake is empty, the reaction force acting on the servo piston from the release chamber side is relatively small, and the brake is rapidly engaged to generate a large shock. It becomes.

[0007] Such a problem arises in an automatic transmission provided with a friction fastening element having a fastening chamber and a release chamber as a hydraulic chamber. It generally occurs widely during gear shifting achieved by the supply of operating pressure.

SUMMARY OF THE INVENTION The present invention addresses the above-mentioned problem in the early stage of running after the engine is started, and it is an object of the present invention to reduce the shock at the time of engaging the frictional engagement element in the early stage of running.

[0009]

That is, the invention according to claim 1 of the present application (hereinafter referred to as "first invention") has a fastening chamber and a release chamber as a hydraulic chamber, and operates only in the fastening chamber. It is configured to be fastened when pressure is supplied and released when both hydraulic chambers are supplied with operating pressure and when both hydraulic chambers are not supplied with operating pressure. In an automatic transmission having a frictional engagement element for switching a power transmission path between a source and a drive wheel, a working pressure adjusting means for adjusting a magnitude of a working pressure supplied to each of the hydraulic chambers, and a working oil in a release chamber Operating oil level information detecting means for detecting information on the remaining amount of the vehicle, control means for controlling the operating pressure adjusting means, running state detecting means for detecting the running state of the vehicle, and detection by the running state detecting means. Of the car Based on the line state with and a fastening state changing means for changing the engagement state of the frictional engagement elements, said control means, upon engagement of the frictional engagement element,
The operating pressure adjusting means is provided so that the magnitude of the operating pressure supplied to the fastening chamber is smaller when the remaining amount of the operating oil in the release chamber is small than when the remaining amount of the hydraulic oil in the release chamber is large. It is characterized in that it is configured to control.

According to a second aspect of the present invention (hereinafter referred to as a "second aspect"), the control means of the first aspect is released until a predetermined period elapses from the start of the engine as compared to after the elapse. It is characterized in that the operating pressure adjusting means is controlled so as to reduce the operating pressure supplied to the fastening chamber, assuming that the remaining amount of the operating oil in the chamber is small.

According to a third aspect of the present invention (hereinafter referred to as a "third invention"), the control means in the first aspect of the present invention is configured to fasten the control means only when the frictional fastening element is fastened by supplying an operating pressure. It is characterized in that the operating pressure adjusting means is controlled so as to reduce the operating pressure supplied to the chamber.

According to a fourth aspect of the invention (hereinafter referred to as a "fourth invention"), the control means of the first invention is controlled by the engine only when the frictional engagement element is engaged by supply of operating pressure. Until a predetermined period elapses from the start, the operating pressure adjusting means is controlled to reduce the operating pressure supplied to the fastening chamber, assuming that the remaining amount of the operating oil in the release chamber is smaller than after the elapse. It is characterized by having done.

The invention according to claim 5 (hereinafter referred to as "the invention")
The "fifth invention") controls the control means in the second or fourth invention so that the operating pressure adjusting means is configured to reduce the operating pressure supplied to the fastening chamber until a predetermined time elapses from the start of the engine. It is characterized in that it is configured to control.

According to a sixth aspect of the present invention (hereinafter referred to as a "sixth aspect"), the control means according to the second or fourth aspect of the present invention is configured such that a shift at which the frictional engagement element is engaged from the start of the engine is predetermined. Until the operation is performed a number of times, the operating pressure adjusting means is controlled so as to reduce the operating pressure supplied to the fastening chamber.

According to the above configuration, the following operation can be obtained.

First, according to the first aspect of the invention, when the remaining amount of the operating oil in the release chamber is small when the frictional engagement element is engaged, the operating pressure supplied to the engagement chamber is controlled to be relatively small. Therefore, the frictional engagement element is prevented from being abruptly engaged, and the shock at the time of engagement is reduced.

According to the second aspect of the present invention, when the frictional engagement element is fastened, the remaining amount of the hydraulic oil in the release chamber is supplied to the engagement chamber until the predetermined period elapses from the start of the engine. Since the operating pressure is controlled to be small, it is possible to prevent the frictional engagement element from being abruptly engaged in the initial stage of running after the engine is started, so that the shock at the time of engagement is reliably reduced.

According to the third aspect of the present invention, the operating pressure supplied to the engagement chamber is controlled to be small only when the frictional engagement element is engaged by supplying the hydraulic oil. In the initial stage of running, the frictional engagement element is smoothly engaged without deteriorating responsiveness.

According to the fourth aspect of the present invention, only when the frictional engagement element is engaged by the supply of hydraulic oil, the operating pressure supplied to the engagement chamber is controlled to be small until a predetermined period has elapsed from the start of the engine. Therefore, the frictional engagement element is smoothly engaged without deteriorating the responsiveness at the beginning of running after the engine is started, so that the shock at the time of engagement is reliably reduced.

According to the fifth aspect of the present invention, the operating pressure supplied to the fastening chamber of the frictional engagement element is controlled to be small until a predetermined time has elapsed from the start of the engine. In the early stage of traveling, the sudden engagement of the friction engagement element is avoided.

According to the sixth aspect of the present invention, the operating pressure supplied to the engagement chamber of the friction engagement element is controlled to be small from the time of starting the engine until a predetermined number of shifts for engaging the friction engagement element are performed. As a result, the frictional engagement element is prevented from being abruptly engaged in the early stage of running after the engine is started.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a first embodiment of the present invention will be described.

First, the mechanical configuration of the automatic transmission 10 according to the first embodiment will be described with reference to FIG. The automatic transmission 10 includes, as main components, a torque converter 20, a transmission mechanism 30 driven by the output of the converter 20, and a plurality of frictional engagement elements such as clutches and brakes for switching a power transmission path of the mechanism 30. 41-
46, and one-way clutches 51 and 52, by which the D, S, L, and R ranges as the driving range, the 1st to 4th speed in the D range, the 1st to 3rd speed in the S range, and the L range The first and second speeds are obtained.

The torque converter 20 is used for the engine 1
Pump 22 fixed in a casing 21 connected to the output shaft 2 of the turbine 2, and a turbine 2 disposed opposite to the pump 22 and driven by the pump 22 via hydraulic oil.
3 and a stator 25 interposed between the turbine 23 and the pump 22 and supported by the transmission case 11 via a one-way clutch 24 to perform a torque increasing action.
And a lock-up clutch 26 provided between the casing 21 and the turbine 23 and directly connecting the engine output shaft 2 and the turbine 23 via the casing 21. The rotation of the turbine 23 is output to the transmission mechanism 30 via the turbine shaft 27.

The engine output shaft 2 is connected to a pump shaft 12 penetrating through the inside of a turbine shaft 27. The shaft 12 drives an oil pump 13 provided on an end face of the transmission 10 on the side opposite to the engine. It has become so.

On the other hand, the transmission mechanism 30 is constituted by a Lapinho type planetary gear device,
Small diameter small sun gear 31 loosely fitted adjacently above
A large sun gear 32 having a large diameter, and a plurality of short pinion gears 3 meshed with the small sun gear 31.
3, a long pinion gear 3 meshed across the short pinion gear 33 and the large sun gear 32.
4, a carrier 35 rotatably supporting the long pinion gear 34 and the short pinion gear 33, and a ring gear 36 meshed with the long pinion gear 34.
It is composed of

A forward clutch 41 and a first one-way clutch 51 are interposed between the turbine shaft 27 and the small sun gear 31 in series, and a coast clutch 42 is arranged in parallel with these clutches 41 and 51. And the turbine shaft 27
A 3-4 clutch 43 is interposed between the turbine shaft 27 and the large sun gear 3.
2, a reverse clutch 44 is interposed.

Between the large sun gear 32 and the reverse clutch 44, a 2-4 brake 45 which is a band brake for fixing the large sun gear 32 is provided, and the carrier 35 and the transmission case 11 are fixed.
Between them, a second one-way clutch 52 for receiving the reaction force of the carrier 35 and a low reverse brake 46 for fixing the carrier 35 are provided in parallel. The ring gear 36 is connected to the output gear 14, and rotation is transmitted from the output gear 14 to left and right drive wheels (not shown) via a differential device.

Here, the frictional engagement elements 41 to 46 such as the clutches and brakes and the one-way clutches 51 and 5 are provided.
Table 1 below summarizes the relationship between the operating state of No. 2 and the shift speed.
It becomes as shown in.

[0030]

[Table 1] As shown in FIG. 2, the hydraulic actuator 45a of the 2-4 brake 45 according to this embodiment is
Servo cylinder 45b provided in the
b, and a fastening chamber 45d and a release chamber 45 are provided on both sides of the servo piston 45c.
e is formed. One end of a piston rod 45f is screwed to the servo piston 45c, and the other end of the piston rod 45f passes through the transmission case 11 and is connected to a brake band 45g. In the release chamber 45e, a servo piston 45c is connected to the fastening chamber 45d.
A return spring 45h biasing to the side is provided inside.

Therefore, the fastening chamber 45d and the release chamber 45
When the operating pressure is not supplied to any of e, the piston rod 45f is pulled through the servo piston 45c by the urging force of the return spring 45h, whereby the brake band 45g is held in a loosened state. 2-4 brake 45 is released. From this state, if an operating pressure is supplied through an oil passage (servo apply line) 61 communicating with the fastening chamber 45d, the servo piston 45c will return the return spring 45h.
The piston ton rod 45f is pushed back against the urging force of the above, whereby the brake band 45g is tightened and the 2-4 brake 45 is engaged. And release room 4
When the operating pressure is supplied through an oil passage (servo release line) 62 leading to 5e, the servo piston 45c pulls the piston rod 45f against the pressure on the fastening chamber 45d side, whereby the brake band 45g is loosened again. 2-4 brake 45 is released. That is, this 2-
4 brake 45 is engaged when the operating pressure is supplied only to the engagement chamber 45d, and when the operating pressure is supplied only to the release chamber 45e,
When the operating pressure is not supplied to both 5d and 45e and when the operating pressure is supplied to both chambers 45d and 45e,
The 2-4 brake 45 is released.

The other friction fastening elements 41 to 44,
Reference numeral 46 has a single hydraulic chamber, and the frictional engagement element is engaged when the operating pressure is supplied to the hydraulic chamber.

In this embodiment, 2-4
Focusing on the brake 45, in the first speed, the fastening chamber 4
The operating pressure is set so as not to be supplied to any of the 5d and the release chamber 45e, the hydraulic oil is supplied only to the fastening chamber 45d in the second speed and the fourth speed, and the engagement chamber 45d and the release pressure are released in the third speed. The operation pressure is set to be supplied to both of the chambers 45e. Therefore, the 2-4 brake 45 is engaged by the supply of the hydraulic oil at the time of shifting from the first speed to the second speed.

Next, a control system of the automatic transmission 10 will be described.

As shown in FIG. 3, a control unit 71 for electrically controlling the automatic transmission 10 includes, for example, a signal from an ignition switch 72 of the engine 1 and a vehicle speed sensor 73 for detecting the vehicle speed of the vehicle. A signal, a signal from a throttle opening sensor 74 for detecting the throttle opening of the engine 1, a signal from a range switch 75 for detecting the speed position of the automatic transmission 10, and an oil for detecting the temperature of the operating oil of the automatic transmission 10. A signal from the temperature sensor 76 or the like is input. The control unit 71 controls the line pressure control by controlling the line pressure control module 63 provided in the hydraulic control circuit based on these signals, and controls the transmission module 64 also provided in the hydraulic control circuit. Gear shift control.
In this case, the line pressure control module 63 includes a regulator valve (not shown) for adjusting the discharge pressure of the oil pump 13 to a predetermined line pressure, and a throttle modulator valve connected to a pressure increasing port of the regulator valve. (Not shown) and a duty solenoid valve (not shown) connected to a control port of the modulator valve. The duty solenoid valve has a well-known configuration in accordance with, for example, a throttle opening representing an engine load. Is turned on and off to generate a throttle modulator pressure corresponding to the throttle opening, and this is introduced into a pressure increasing port of a regulator valve, thereby increasing the line pressure adjusted by the valve. Will be. The transmission module 64 includes a plurality of shift valves (not shown) connected to the hydraulic chambers of the friction engagement elements 41 to 46, and a plurality of ON-switches connected to control ports of the shift valves. A well-known configuration having an OFF solenoid valve (not shown)
By selectively turning on and off the -OFF solenoid valve, the position of the spool of the shift valve is switched.

Here, the shift control performed by the control unit 71 will be briefly described. The control unit 71 includes, for example, the vehicle speed of the vehicle input from the vehicle speed sensor 73 and the engine input from the throttle opening sensor 74. The throttle position is determined by applying the throttle opening of 1 to a shift map in which the operating state (vehicle speed and throttle opening) is set as a parameter in advance. Then, a shift signal is output to the shift module 64 so that the determined shift stage is obtained. Thereby, the ON-OF of the transmission module 64
When the F solenoid valve is turned on and off, the spool position of each shift valve is switched, and the oil passage leading to each of the friction fastening elements 41 to 46 is switched. The gears are fastened in the combinations shown in Table 1, whereby the gears are switched according to the operating conditions.

Next, the line pressure control, which is a feature of the first embodiment, will be described with reference to the flowchart of FIG.

The control unit 71 first reads various signals in step S1, and then executes step S2 to determine whether or not the ignition switch 72 is ON. If it is determined that the ignition switch 72 is not ON, the process proceeds to step S3, where the timer value T indicating the time since the ignition switch 72 was turned ON is set to 0, and the process returns to step S1.

On the other hand, the control unit 71 executes step S
When it is determined in step 2 that the ignition switch 72 is in the ON state, the process proceeds to step S4, where the timer value T is incremented. Then, step S5 is executed and the timer value T exceeds the predetermined value To. It is determined whether or not. That is, the control unit 71 measures the time since the start of the engine 1 and determines whether a predetermined time (for example, about 10 minutes) has elapsed since the start of the engine 1, in other words, several times. 4 brakes 4
Then, it is determined whether or not the time that is considered to have engaged No. 5 has elapsed. Instead of the time from when the engine 1 is started, a signal from the range switch 75 may be monitored to measure the time from when the engine 1 is set to the driving range such as the D range.

If the control unit 71 determines in step S5 that the timer value T has not exceeded the predetermined value To, it executes step S6 to set 0.8 as the line pressure time correction coefficient Ka. . That is, the magnitude of the line pressure is reduced.

The control unit 71 executes the step S6 to set the time correction coefficient Ka, and then executes the step S7 to execute the oil temperature correction coefficient setting using the oil temperature as a parameter as shown in FIG. , The oil temperature correction coefficient Kb corresponding to the actual oil temperature t is calculated. This is because if the temperature of the hydraulic oil is low, the operation delay is caused by its viscosity.

Next, the control unit 71 proceeds to step S
8 by referring to a map of the basic line pressure in which the throttle opening as a substitute characteristic of the input torque of the automatic transmission 10 is set as a parameter as shown in FIG. After the basic line pressure Po corresponding to is calculated, step S9 is executed to set the final line pressure Pl. The final line pressure Pl is set, for example, as a value obtained by multiplying the basic line pressure Po by the time correction coefficient Ka and the oil temperature correction coefficient Kb. And
The control unit 71 executes step S10, outputs a line pressure control signal to the line pressure control module 63 so as to obtain the final line pressure P1, and returns to step S1.

On the other hand, when the control unit 71 determines in step S5 that the timer value T has exceeded the predetermined value To, it proceeds to step S11, sets 1 as the time correction coefficient Ka of the line pressure, and then sets Returning to step S7, the oil temperature correction coefficient Kb is calculated.

As described above, the magnitude of the line pressure, in other words, the magnitude of the operating pressure supplied to the engagement chamber 45d of the 2.4 brake 45 is not changed until the predetermined time elapses after the engine 1 starts. , The shock when the brake 45 is engaged is reduced.

Next, a second embodiment of the present invention will be described. Note that the mechanical configuration, control system, and shift control of the automatic transmission are basically the same as those of the first embodiment, and therefore detailed description is omitted, and the same reference numerals are used for common elements.

In this embodiment, the line pressure control is performed as follows in accordance with the flowchart of FIG.

That is, the control unit 71 executes step S21 to read various signals, and then executes step S22 to determine whether or not a 1-2 shift is performed. That is, when the release chamber 45e of the 2-4 brake 45 is empty,
It is determined whether or not the brake 45 is engaged.

The control unit 71 proceeds to step S22.
When it is determined that the shift is the 1-2 shift, the process proceeds to step S23, and it is determined whether the 1-2 shift count value C is greater than the switching determination value Co. That is, it is determined whether the number of times of the 1-2 shift after starting the engine has reached a predetermined number.

The control unit 71 proceeds to step S23.
When it is determined that the 1-2 shift count value C is not larger than the switching determination value Co in step 2, step S24 is executed to set 0.8 as the line pressure time correction coefficient Ka.

The control unit 71 executes the processing in step S24
Is executed to set the time correction coefficient Ka. Then, by executing step S25, the actual oil is referred to by referring to the oil temperature correction coefficient map shown in FIG. 5 as in the first embodiment. An oil temperature correction coefficient Kb corresponding to the temperature t is calculated.

Next, the control unit 71 proceeds to step S
By executing step 26, as in the first embodiment,
Referring to the basic line pressure map shown in FIG. 6, after calculating the basic line pressure Po corresponding to the actual throttle opening θ, step S27 is executed to set the final line pressure Pl, and step S28 is executed. By executing, the line pressure control signal is output to the line pressure control module 63 so that the final line pressure Pl is obtained.

On the other hand, the control unit 71 determines in step S25 that the 1-2 shift count value C is equal to the switching determination value C.
If it is determined that it is larger than o, the process proceeds to step S29, where 1 is set as the time correction coefficient Ka of the line pressure, and then the process returns to step S25 to calculate the oil temperature correction coefficient Kb.

If the control unit 71 determines in step S22 that it is not the 1-2 shift, the process proceeds to step S30, where the time correction coefficient K for the line pressure is determined.
After setting 1 as a, the flow returns to step S25 to calculate the oil temperature correction coefficient Kb.

The control unit 71 executes the 1-2 shift count in accordance with the flowchart of FIG. 8 as follows in parallel with the line pressure control.

That is, the control unit 71 executes step S
After reading various signals by executing step 41, step S
Step 42 is executed to determine whether the third speed command signal has been output. If it is determined that the third speed command signal has been output, step S43 is executed to increment the third speed command output count value Ct, and then the process proceeds to step S44 where the third speed command output count value Ct is smaller than the predetermined value Cto. It is determined whether it is larger. That is, the third speed command signal is continuously output, and the release chamber 4 of the 2-4 brake 45 is actually output.
It is determined whether the hydraulic oil is supplied to 5e without fail.

The control unit 71 performs the processing in step S44
When it is determined that the third speed command output count value Ct is greater than the predetermined value Cto in step S45, the process proceeds to step S45 to determine whether or not the 1-2 shift count permission flag F has been set to 1. When it is determined that it is set to 1, the process proceeds to step S46, where 1-2
After incrementing the shift count value C, step S47 is executed to execute the 1-2 shift count permission flag F
Is set to 0, and the process returns to step S41.

The control unit 71 proceeds to step S45.
In step S46, when it is determined that the 1-2 shift count permission flag F is not set to 1,
Skip S47 and return to step S41. Therefore, even if the shift speed is fixed to the third speed and the third speed command signal is continuously output, the 1-2 shift count value C is not incremented indefinitely.

On the other hand, when the control unit 71 determines in step S42 that the third speed command signal has not been output, the control unit 71 proceeds to step S48, resets the third speed output count value C, and proceeds to step S49. The program is executed to set 1 to the 1-2 shift count permission flag F, and the process returns to step S41.

As described above, in the second embodiment, after the engine 1 is started, the line shifting is performed as compared with the normal time until the 1-2 shift in which the 2-4 brake 45 is engaged is performed a predetermined number of times. Since the pressure is reduced, the shock when the brake 45 is engaged is reduced. In addition, when the remaining amount of hydraulic oil in the release chamber 45e is small,
Since the line pressure is reduced only at the time of the 1-2 shift in which the 4 brake 45 is engaged, the responsiveness at the time of the normal shift is not deteriorated.

In the above embodiment, 2-
Although the four-brake 45 has been described, the present invention can be widely applied to a friction fastening element having a fastening chamber and a release chamber as a hydraulic chamber.

[0061]

As described above, according to the present invention, the hydraulic chamber has the fastening chamber and the release chamber, and the hydraulic chamber is engaged only when the operating pressure is supplied only to the fastening chamber. In the release chamber when the frictional engagement element is engaged in an automatic transmission provided with a frictional engagement element configured to be released when the hydraulic pressure is supplied and when both hydraulic chambers are not supplied with the operating pressure. When the remaining amount of oil is small, the magnitude of the operating pressure supplied to the engagement chamber is controlled to be small, so that the frictional engagement element is prevented from suddenly engaging and the shock at the time of engagement is reduced. Will be done.

[Brief description of the drawings]

FIG. 1 is a skeleton diagram of an automatic transmission according to a first embodiment.

FIG. 2 is a sectional view of a main part of a hydraulic actuator of a 2-4 brake similarly provided in the automatic transmission.

FIG. 3 is a control system diagram of the automatic transmission.

FIG. 4 is a flowchart illustrating line pressure control according to the first embodiment.

FIG. 5 is an explanatory diagram of a map of an oil temperature correction coefficient using oil temperature as a parameter.

FIG. 6 is an explanatory diagram of a map of a basic line pressure using a throttle opening as a parameter.

FIG. 7 is a flowchart illustrating line pressure control according to a second embodiment.

FIG. 8 is a flowchart showing a 1-2 shift counting process.

[Explanation of symbols]

 Reference Signs List 1 engine 10 automatic transmission 45 2-4 brake 45d fastening chamber 45e release chamber 63 line pressure control module 64 transmission module 71 control unit 72 ignition switch 73 vehicle speed sensor 74 throttle opening sensor 75 range switch

Claims (6)

[Claims] 1. A hydraulic chamber having a fastening chamber and a release chamber,
It is configured to be engaged when operating pressure is supplied only to the fastening chamber, and to be released when operating pressure is supplied to both hydraulic chambers and when operating pressure is not supplied to both hydraulic chambers. A control device for an automatic transmission having a frictional engagement element for switching a power transmission path between a drive source and a drive wheel by changing a state, wherein an operation for adjusting a magnitude of a working pressure supplied to each of the hydraulic chambers is performed. Pressure adjusting means, hydraulic oil remaining information detecting means for detecting information on the remaining amount of hydraulic oil in the release chamber, control means for controlling the operating pressure adjusting means, and running state detection for detecting the running state of the vehicle Means, and engagement state changing means for changing the engagement state of the friction engagement element based on the traveling state of the vehicle detected by the traveling state detection means, and the control means comprises: At the time of element fastening, the magnitude of the operating pressure supplied to the fastening chamber is set to be smaller when the remaining amount of hydraulic oil in the release chamber is small than when the remaining amount of hydraulic oil in the release chamber is large. A control device for an automatic transmission, wherein the control device controls an operating pressure adjusting means. 2. The control means according to claim 1, wherein, until a predetermined period elapses from the start of the engine, the operating pressure supplied to the fastening chamber is reduced, assuming that the remaining amount of hydraulic oil in the release chamber is smaller than that after the elapse. The control device for an automatic transmission according to claim 1, wherein the control device is configured to control the operating pressure adjusting means. 3. The control means is configured to control the working pressure adjusting means so as to reduce the working pressure supplied to the fastening chamber only when the friction fastening element is fastened by supplying the working pressure. The control device for an automatic transmission according to claim 1, wherein: 4. The control means according to claim 1, wherein only when said friction engagement element is engaged by supply of the operating pressure, the remaining amount of hydraulic oil in the release chamber is smaller than that after the elapse of a predetermined period from the start of the engine. 2. The control device for an automatic transmission according to claim 1, wherein the control device controls the operating pressure adjusting means so as to reduce the operating pressure supplied to the fastening chamber. 5. The control means is configured to control the operating pressure adjusting means so as to reduce the operating pressure supplied to the fastening chamber until a predetermined time has elapsed from the start of the engine. The control device for an automatic transmission according to any one of claims 2 and 4. 6. The control means controls the working pressure adjusting means so as to reduce the working pressure supplied to the fastening chamber from a time when the engine is started until a predetermined number of shifts in which the friction fastening element is engaged are performed. The control device for an automatic transmission according to claim 2, wherein the control device is configured.