JP2912033B2 - Hydraulic control device for automatic transmission for vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic control device for an automatic transmission for a vehicle for automatically controlling a shift of an automatic transmission suitable for use in a vehicle such as an automobile.

[0002]

2. Description of the Related Art Conventionally, there is an automobile which uses an automatic transmission in which a shift operation of a transmission is performed by hydraulic control, and in general, according to a vehicle speed and a throttle opening as a parameter of an engine load. 2. Description of the Related Art There has been known an automatic gear shifter that automatically shifts gears based on a predetermined shift characteristic. In the automatic transmission having the above-described structure, when performing a downshift shift operation performed by kicking down from depressing an accelerator pedal from a high speed stage to a low speed stage, the engine speed is adjusted according to the gear ratio of the low speed stage. When the gears meshing with each other are appropriately increased to synchronize with each other, shock due to torque fluctuation can be reduced. For example, as disclosed in JP-A-61-84450,
In order to discharge the high-speed gear hydraulic engagement element for establishing the high-speed gear transmission, the supply pressure of the low-speed gear hydraulic engagement element for establishing the low-speed gear transmission is predetermined. There is known an oil discharge control valve that switches so as to open an oil discharge passage for performing the above-described exhaust pressure when the pressure reaches a value.

[0003] In the automatic transmission having the above structure, for example, when the gear is shifted from the fourth gear, which is a high gear, to the second gear, which is a low gear, by kick down, the hydraulic engagement for the high gear is used. The engagement pressure P4 of the fourth speed clutch as an element changes as shown by the imaginary line in the upper part of FIG. At this time, the initial pressure reduction of the engagement pressure P4 is relatively gently performed through a fixed orifice such as a throttle provided in a drainage passage of the fourth speed clutch, and the subsequent pressure reduction is also provided in parallel with the fourth speed clutch. Since the pressure of the accumulator for alleviating the clutch engagement shock is reduced, the operation is performed relatively slowly. Then, in response to the increase in the engagement pressure P2 of the second speed clutch acting on the land of the valve element, the valve element that is spring-biased toward the side that closes the oil discharge passage moves against the urging force. Then, the drain control valve opens (a in the figure). That is, since the oil is drained from the oil drain control valve in addition to the fixed orifice, the pipeline resistance due to the oil drain resistance and the like becomes small, and the engagement pressure P4 of the fourth speed clutch decreases relatively sharply from the time of valve opening. And it is completely exhausted.

Thus, the engagement pressure P2 of both clutches
P4 is supplied and discharged, and the engine speed changes as indicated by the imaginary line in the middle part of FIG. 3 according to the change. At the beginning of the shift, the engine speed gradually increases, but as described above, the exhaust pressure of the fourth-speed clutch is gently performed, and the torque transmission is performed to some extent by the engagement state of the fourth speed. Because it is. Thereafter, the engagement force decreases in accordance with the exhaust pressure of the fourth speed clutch, and further, as described above, the valve is opened by switching of the oil discharge control valve, and
Since the engagement pressure of the speed clutch rapidly decreases, the engine speed rapidly increases. Further, since the engagement pressure of the fourth-speed clutch sharply decreases and the engagement pressure of the second-speed clutch sharply increases, the vehicle body acceleration G also decreases from the negative acceleration as indicated by the imaginary line in the lower part of the figure. There has been a problem that the acceleration changes sharply to a positive acceleration, and the occupant feels a shift shock due to the change.

[0005]

[Problems that the Invention is to Solve In view of such problems of the prior art, with the main objective of the present invention may reduce the shift shock at the time of performing the shift operation of the downshift performed by depressing the accelerator pedal It is an object of the present invention to provide a hydraulic control device for an automatic transmission for a vehicle, which is improved so as to quickly release the pressure.

[0006]

Means for Solving the Problems] Such object is achieved according to the present invention, the boost pressure and speed to the low speed stage for oil pressure coefficient Goyo containing
In the hydraulic control system for an automatic transmission for a vehicle which performs downshift by the discharge pressure from the hydraulic engagement element for stage a oil discharge passage of the high speed stage hydraulic engagement elements selectively be opened and closed and An oil drain control valve having a valve element which is resiliently biased in a closing direction; and the valve element for applying a hydraulic pressure to move the valve element in a direction to open the oil drain passage against the urging force. And first and second pressure receiving surfaces provided on the first pressure receiving surface during a downshift operation from a high speed stage to a low speed stage. Let it act on
Co The provision of switching valve switches to cormorants, the hydraulic control of the automatic transmission, characterized in that the feed pressure of the low-speed stage hydraulic engaging element for a so as to act at all times to the second pressure receiving surface This is achieved by providing a device.

[0007]

In this manner, both the exhaust pressure from the high-speed gear hydraulic engagement element and the supply pressure to the low-speed gear hydraulic engagement element during the downshift shifting operation performed by depressing the accelerator pedal. In order to move the valve element of the oil drain control valve for changing the pipe resistance (oil drain resistance, throttle, etc.) of the oil drain of the high-speed stage hydraulic engagement element using The valve body is quickly moved by a large exhaust pressure from the high-speed gear hydraulic engagement element, and the exhaust pressure from the high-speed gear hydraulic engagement element decreases in the latter half of the shift. The valve element can be moved by increasing the supply pressure of the combined element. Therefore, it is possible to quickly release the pressure from the high-speed gear hydraulic engagement element at the beginning of the shift.

[0008]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a preferred embodiment of the present invention. FIG. 1 is a schematic diagram showing an outline of an automatic transmission of an automobile to which the present invention is applied. In FIG. 1, an automatic transmission 2 is connected to an engine 1, and a torque converter 3 with a lock-up clutch and, for example, a forward four-stage reverse one-stage gear transmission 4 with a hold clutch are provided in the automatic transmission 2. Is built-in. The final drive gear 4a of the gear transmission 4 is meshed with a ring gear of a differential 6 connected to the drive wheels 5, and the engine 1
Is transmitted to the drive wheels 5 via the torque converter 3 and the gear transmission 4.

Each shift speed of the automatic transmission 2 is controlled by a control unit 7 as automatic shift control means in accordance with a vehicle speed signal and a throttle opening signal as an engine load.
Is controlled to automatically change the speed. The control unit 7 comprises a combination of general circuits,
It has a CPU, a ROM, a RAM, and input / output circuits 7a and 7b. The input circuit 7a includes a final drive gear 4
For example, a pulse signal is input as a vehicle speed signal from a vehicle speed sensor 8 provided in the vicinity of a, and a voltage signal is also output as a throttle opening signal from a throttle opening sensor 9 mounted on a throttle body (not shown) of the engine 1. Has been entered. The input circuit 7a receives, for example, a signal of an air conditioner or a cooling water temperature from various signal sensors 10 to be used as a condition for speed change control.

In the control unit 7, a shift map control according to each signal input to the input circuit 7a is performed using a CPU, a ROM, and a RAM. A shift control signal and a lock-up control signal are output from an output circuit 7b of the control unit 7 to each solenoid valve SV such as a shift control and a lock-up control of the hydraulic control circuit 11. The gears of each speed stage of the automatic transmission 2 are automatically switched by the hydraulic control circuit 11,
Further, the engagement state of the lock-up clutch is controlled.

The gear transmission 4 is, for example, a constant mesh type, and has an input shaft 12, an output shaft 13, and a counter shaft 14 which are parallel to each other. A counter shaft 14 gear-coupled to the input shaft 12 via an idle gear
Is provided with a first speed clutch 15 for establishing a first speed stage and a second speed clutch 16 for establishing a second speed stage. The input shaft 12 establishes a third speed stage. 3 for
A speed clutch 17 and a fourth speed clutch 18 for establishing a fourth speed are provided. Further, the output shaft 13 is provided with a one-way clutch 19 coupled to the first-speed gear so as to allow overspeed of the output shaft 13 side. The torque is not transmitted. Therefore, when another gear is established, torque is transmitted to the output shaft 13 without passing through the one-way clutch 19. Also, a hold clutch LH is provided in parallel with the one-way clutch 19,
In the engaged state of the hold clutch LH, torque is transmitted via the hold clutch LH, bypassing the one-way clutch 19.

FIG. 2 is a schematic hydraulic circuit diagram showing a main part of a hydraulic control circuit 11 to which the present invention is applied. In the figure, a supply / discharge port 18a to / from an oil chamber of a fourth speed clutch 18 and a first port 20a of a manual valve 20 are connected to a first oil passage 21.
Are in communication with each other. This manual valve 20
In the figure, the spool 22 can be displaced in the left-right direction in the figure. In the figure, the D range in which the gears can be automatically shifted from the first gear to the fourth gear is selected. In the state shown, the first port 20a
Port 20b of the manual valve 20 communicating with each other
Is connected via a second oil passage 24 to a first port 23a of a 3-4 shift valve 23 as a switching valve . The spool 25 of the 3-4 shift valve 23 is elastically biased by a spring 26 toward the right side in the figure. In the figure, a state is shown in which the second speed stage, which is the low speed stage, is selected after traveling at the fourth speed stage, which is the high speed stage. In this second speed stage selected state, the side opposite to the spring 26 is shown. The hydraulic oil is not supplied from the second port 23b to the oil chamber via a control valve (not shown), and the spool 25 is spring-biased rightward as shown in the figure.

The spool 25 of the 3-4 shift valve 23 has a third port 2 which communicates with the first port 23a via an outer peripheral groove of the spool 25 in a state where the second speed is selected.
A first oil discharge passage 27 that is open to the atmosphere via a fixed orifice 28 is connected to the third port 23c. Thus, in the illustrated state, high-speed
The exhaust pressure of the fourth-speed clutch 18 as the first-stage hydraulic engagement element is performed via the fixed orifice 28 of the first oil passage 27.

The fixed orifice 28 of the first oil drain passage 27
Is connected to the first input port 29a of the oil discharge control valve 29. Due to the exhaust pressure supplied to the first input port 29a, the spool 31 as a valve body urged by the spring 30 toward the left of the oil discharge control valve 29 in the figure is moved rightward against the spring urging force. The first of the spool 31 is moved toward
The first input port 29 is connected to the first land 31a as the pressure receiving surface.
The exhaust pressure supplied to a is applied. Also,
The drain control valve 29 has second to fourth input ports 29b to 29.
d is provided, and the second input port 29b has a low speed.
A supply / discharge port 17a to / from the oil chamber of the third speed clutch 17 as a stage hydraulic engagement element is connected via a third oil passage 32, and a low speed stage hydraulic engagement is connected to the third input port 29c. Required
Supply / discharge port 16 for the oil chamber of second speed clutch 16
a is connected via a fourth oil passage 33, and the spool 31 is moved so as to move the spool 31 against the spring urging force by the exhaust pressure selectively supplied to each of the ports 29b and 29c. Second and third lands 3 as second pressure receiving surfaces
The exhaust pressure supplied to each port 29b / 29c is applied to 1b / 31c.

A sub-branch 27b further branched from the branch 27a is connected to a fourth input port 29d of the oil discharge control valve 29.
When the drain pressure is appropriately applied to the lands 30a, 30b, and 30c, the spool 31 moves rightward in the drawing against the urging force of the spring 30. When moved, the oil drain port 34 communicates with the fourth input port 29d via the outer circumferential groove of the spool 31.
Is provided.

The fourth port 23 of the 3-4 shift valve 23
A branch passage 32a branched from the third oil passage 32 connected to the supply / discharge port 17a of the third speed clutch 17 is connected to d. The 3-4 shift valve 23 is provided with a fifth port 23e which communicates with the fourth port 23d via the outer peripheral groove of the spool 25 in the illustrated state, and a fifth port 23e connected to the fifth port 23e. The oil passage 35 is provided with a second oil passage 37 opened to the atmosphere via a fixed orifice 36.
Are selectively connected through a 2-3 shift valve 38. An oil supply path 39 connected to a hydraulic pump (not shown) is selectively connected to a branch path 33 a branched from the fourth oil path 33 via a 2-3 shift valve 38. I have.

In the hydraulic control circuit constructed as described above, when performing the downshift operation from the fourth speed to the second speed, the engagement hydraulic pressure of the hydraulic chamber of the fourth speed clutch 18 is released. The clutch is changed from the engaged state to the released state. This exhaust pressure is performed via the first oil discharge passage 27 by the communication between the first and third ports 23a and 23c of the 3-4 shift valve 23 as described above. The pressure is released through the branch passage 27.
a to the first input port 29a of the oil discharge control valve 29 to act on the first land 31a.
The spool 31 moves to the right in the drawing against the urging force of. At this time, as described above, the operation of the 2-3 shift valve 38 applies a hydraulic pressure to the hydraulic chamber of the second speed clutch 16 so that the second speed clutch 16 is engaged. It also acts on the third land 31c via the three input port 29c. In this case, the increase and decrease of both oil pressures are changed as indicated by a clutch oil pressure line P4 indicating the exhaust pressure of the fourth speed clutch 18 and a clutch oil pressure line P2 indicating the supply pressure of the second speed clutch 16 in the upper part of FIG. I do.

According to the present invention, the driving force F for opening the oil discharge port 34 with respect to the spool 31 of the oil discharge control valve 29, which is switched to discharge the pressure of the fourth speed clutch 18, is equal to the discharge pressure P4 of the fourth speed clutch 18. First land 3 that receives the pressure
1 a to that area Sa by multiplying the area of the second land 31b which receives the pressure Kyu圧P2 of the second clutch 16 S
b multiplied by b (F = P4 · S
a + P2 · Sb). When the driving force F becomes larger than the spring force of the spring 30 that resiliently biases the spool 31 in the direction to close the oil drain port 34, the fourth input port 29
The oil communication port d communicates with the oil drain port 34, so that the fourth speed clutch 18 is largely drained.

Immediately after the start of the above-mentioned shifting operation, the engagement hydraulic pressure of the second speed clutch 16 on the low speed stage is low, and mainly the exhaust pressure of the fourth speed clutch 18 on the high speed stage which has been engaged so far. , The spool 31 is moved in the valve opening direction by the high pressure, so that the second speed clutch 16 which is the conventional low speed stage side
The valve opening operation is performed very quickly in response to the valve opening operation after waiting for the increase in the engagement hydraulic pressure. Therefore, as shown in the upper part of FIG. 3, the engagement hydraulic pressure of the fourth-speed clutch 18 on the high-speed stage side is rapidly reduced with respect to the exhaust pressure curve shown by the imaginary line of the conventional example. Then, 2 corresponds to the ratio of each area Sa and Sb of the first land 29a and the second land 29b.
The pressure reduction of the fourth speed clutch 18 is performed according to the pressure increase of the speed clutch 16, and the driving force F can be kept substantially constant by suitably setting the area ratio.

As described above, since the oil discharge control valve 29 operates while the pressure is regulated, the engagement hydraulic pressure of the clutch changes relatively smoothly as shown in FIG. Therefore,
This is because the transmission torque on the high speed side decreases due to the decrease in the engagement hydraulic pressure on the clutch on the high speed side due to the increase in the transmission torque on the low speed side due to the increase in the engagement hydraulic pressure on the clutch on the low speed side. The change in the transmission torque during the shift process is small, the change in the vehicle body acceleration G shown in the lower part of FIG. 3 is small, and the shock during the shift is extremely small. If the force in the valve opening direction on the spool 31 due to the engagement hydraulic pressure of the second speed clutch 16 overcomes the urging force of the spring 30, the valve is opened only by the engagement hydraulic pressure of the second speed clutch 16 and the fourth speed clutch The engagement hydraulic pressure at 18 is completely exhausted.

In the above-described embodiment, the downshift from the fourth speed to the second speed is described. However, the same applies to the shift to another speed. For example, at the time of the downshift from the fourth speed to the third speed, The 2-3 shift valve 38 is switched so that the oil supply path 39 and the fifth oil path 35 communicate with each other, and the engagement hydraulic pressure of the third speed clutch 17 can be increased. This third speed clutch 17
The engagement hydraulic pressure of the second port 2 of the oil discharge control valve 29
9b and acts on the second land of the spool 31. Therefore, at the beginning of the shift, the oil discharge control valve 29 is quickly opened by the exhaust pressure of the fourth speed clutch 18, and even if the exhaust pressure decreases, the valve opening operation is performed by increasing the engagement hydraulic pressure of the third speed clutch 17. Is continued, and a smooth shift is performed in the same manner as described above.

[0022]

As is apparent from the above description, according to the hydraulic control apparatus of the present invention, the pressure supply to the low-speed gear hydraulic engagement element during the shift operation from the high gear to the low gear is performed. Opening operation of the oil discharge control valve by the valve drive force in the valve opening direction that changes relatively smoothly in combination with the increase and decrease of the oil pressure of both due to the exhaust pressure of the high speed stage hydraulic engagement element Control of the high-speed gear hydraulic engagement element to reduce the change in the exhaust pressure. Operational quality can be improved. In addition,
Control of the exhaust pressure of the high-speed gear hydraulic engagement element during shift operation
By acting on the valve, the high-speed gear hydraulic engagement element
Oil release control with own exhaust pressure at the start of shift shift operation
Since the control valve can be opened, the exhaust pressure can be quickly increased.
You.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an outline of an automatic transmission of an automobile to which the present invention is applied.

FIG. 2 is a schematic hydraulic circuit diagram showing a main part of a hydraulic control device for an automatic transmission of an automobile to which the present invention is applied.

FIG. 3 is a diagram showing an operation at the time of a shift operation in the embodiment.

[Description of Signs] 1 Engine 2 Automatic transmission 3 Torque converter 4 Gear transmission 4a Final drive gear 5 Driving wheel 6 Differential device 7 Control unit 7a Input circuit 7b Output circuit 8 Vehicle speed sensor 9 Throttle opening sensor 10 Various signal sensors Reference Signs List 11 hydraulic control circuit 12 input shaft 13 output shaft 14 counter shaft 15 1st speed clutch 16 2nd speed clutch 16a supply / discharge port 17 3rd speed clutch 17a supply / discharge port 18 4th speed clutch 18a supply / discharge port 19 one-way clutch 20 manual valve 20a 1 port 21 first oil path 22 spool 23 3-4 shift valve 23a to 23e first to fifth port 24 second oil path 25 spool 26 spring 27 first oil discharge path 27a branch path 27b sub-branch path 28 fixed Orifice 29 Drainage control valve 29a-29 d First to fourth input ports 30 Spring 31 Spool 31a to 31c First to third lands 32 Third oil path 32a Branch path 33 Fourth oil path 33a Branch path 34 Oil discharge port 35 Fifth oil path 36 Fixed orifice 37 Second oil discharge path 38 2-3 shift valve 39 Oil supply path

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) F16H 59/00-61/12 F16H 61/16-61/24 F16H 63/40-63/48

Claims (1)

(57) [Claims] 1. A feed pressure and high to low speed gear oils pressure coefficient Goyo containing
In the hydraulic control system for an automatic transmission for a vehicle which performs <br/> downshift by the discharge pressure from the hydraulic engagement element for the speed stage, selectively the oil discharge passage of the hydraulic engaging element for the high speed stage An oil discharge control valve having a valve element that can be opened and closed and resiliently urged in a closing direction, and an oil pressure acting to move the valve element in a direction to open the oil discharge passage against the urging force. And first and second pressure receiving surfaces provided on the valve element to perform a downshift operation from a high-speed gear to a low-speed gear. co the first providing the switching valve is switched so as to act on the pressure receiving surface, and characterized in that the boost pressure of the to low speed stage hydraulic engaging element for a so as to act at all times to the second pressure receiving surface Control device for automatic transmission for vehicles.