JPS62233553A - Control device for automatic transmission - Google Patents

Abstract

PURPOSE:To enable the shock of speed change to be prevented by a simple hydraulic control circuit, by reducing the line pressure of hydraulic oil for a determined time by means of the control signals from a speed change control part to a lower level of pressure where one side friction member can still maintain its engaging state. CONSTITUTION:For instance, in the case of shifting up from 1st speed to 2nd speed, 1st brake 23, which is one of friction members, is shifted from the open state to the engaging state, while 1st clutch 20, the other friction member, is still maintaining its engaging state. In this speed change, the line pressure of hydraulic oil is reduced by the signal from the speed change control part for a determined time to a certain level of pressure which is within the range where the pressure is sufficient to maintain the engaging state of said 1st clutch 20. Due to the above construction, speed change can be accomplished in a determined timing while appropriately controlling the line pressure of the hydraulic oil for the other friction member without provision of an accumulator, thus enabling the shock of speed change to be prevented by a simple hydraulic control circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention provides an automatic transmission that automatically changes gears according to the driving condition of an automobile, etc. The present invention relates to an improvement in a control device for an automatic transmission configured to control the supply and discharge of hydraulic oil to and from members to perform gear shifting operations.

(Prior art) Conventionally, in order to control the gear shift timing according to the driving condition of an automobile, etc., and to simplify the configuration of the hydraulic control circuit, the accelerator pedal depression amount, engine rotation speed,
The vehicle speed, engine load, etc. are electrically detected, and a control signal corresponding to the detected value is output from the control means to the solenoid valve mechanism to switch the power transmission path of the 11 gears such as brakes and clutches. There are devices that control the supply and discharge of hydraulic oil supplied to friction members (for example, Japanese Patent Laid-Open No. 6
0-37448).

In the conventional device described in this publication, the duty ratio of the control signal output at the time of initial engagement of the friction member is adjusted based on the engine speed and load in order to smoothly perform torque fluctuations during gear changes and reduce shift shock. By changing the duty rate during engagement of the friction member according to the throttle valve opening of the engine,
The supply and discharge of hydraulic oil to and from the friction member is controlled. In other words, for example, at low loads with little transmitted torque, the duty ratio at the time of initial engagement is increased to lower the hydraulic oil line pressure, thereby preventing shift shock at the time of initial engagement, and reducing the duty ratio during engagement. By setting the amount of change in the ratio gently, shift shock that occurs during engagement is prevented. Also,
When the transmission torque is high and the load is large, the line pressure at the time of initial engagement is set low, and the amount of change in the duty rate is controlled so that the rise of the line pressure during engagement is set to be large. This is intended to prevent gear shift shocks and prevent the gear shift time from becoming longer than a predetermined value.

However, in the control device having the above configuration, no consideration is given to the gear position in which the gear is changed by shifting the other friction member from the released state to the engaged state while maintaining one friction member in the engaged state. For this purpose, the rising speed of the hydraulic oil that connects the other friction member must be set to a predetermined value (
・Although it requires an accumulator to properly control the operating speed by setting the hydraulic oil line pressure to could not.

(Object of the invention) The present invention has been made based on the above technical background,
To simplify the structure of a hydraulic control circuit as much as possible in a control device for an automatic transmission configured to duty-control the line pressure of hydraulic oil supplied to a friction member according to a control signal output from a control means. It is an object.

(Structure of the Invention) The present invention includes a torque converter connected to the output shaft of an engine, a speed change gear mechanism disposed on the output side of the torque converter, and a speed change operation by switching the power transmission path of the speed change gear mechanism. A control device for an automatic transmission comprising: a plurality of friction members, a solenoid valve that controls the supply and discharge of hydraulic oil to and from the friction members; and a control means that controls the operation of the solenoid valves, the control device comprising: During a gear shift operation in which the other friction member is shifted from the released state to the engaged state while maintaining the engaged state of the member, the line pressure of the hydraulic oil is set to be sufficient to maintain the engaged state of one friction member. A speed change control section is provided that outputs a control signal that decreases the speed within the range for a predetermined period of time.

According to the above configuration, one of the friction members is maintained in a fastened state and the line pressure of the hydraulic oil is reduced in response to a control signal output from the speed change control section, and then together with this friction member, the other friction member is moved to a predetermined position. The transmission shifts to the engaged state at the rising speed of , and the gear shift is performed at an appropriate timing.

(Example) Fig. 1 shows the overall configuration of an automatic transmission according to the present invention. The torque converter 2 includes a pump 3, a turbine 4, and a stator 5, and the pump 3 is fixed to the crankshaft 1.

The stator 5 rotates via a one-way clutch 6 on a fixed shaft 7 that is integrated with the case 11 of the speed change gear mechanism 10 .

The one-way clutch 6 allows the stator 5 to rotate in the same direction as the pump 3, but does not allow rotation in the reverse direction.

The speed change gear mechanism 10 has a base end fixed to the crankshaft 1, a tip extending through the center of the speed change gear mechanism 10, and an oil pump 10 disposed on a side wall of the device 10.
A solid shaft 12 connected to this oil pump 100 is provided to drive the oil pump 100. On the outside of this solid shaft 12, a base end is connected to the turbine 4 of the torque converter 2, and a distal end extends to the side wall of the speed change gear mechanism 10,
A hollow turbine shaft 13 rotatably supported by this side wall is provided. On this turbine shift 13, a Lavigneaux 1 planetary gear A unit 14 is provided, and this planetary gear unit 14 is
It consists of a small-diameter sun gear 15, a large-diameter sun gear 16 disposed on the side of the small-diameter sun gear 15 far from the engine, a long pinion gear 17, a short pinion gear 18, and a ring gear 19. On the side of this planetary gear unit 14 far from the engine, there is a first gear:
and a second clutch device 20.21 are arranged in parallel. The first clutch device 20 is a clutch for forward running, and connects and disconnects power transmission between the small diameter ring gear 15 and the turbine shaft 13 via the first one-way clutch 22.

On the other hand, the second clutch device @21 connects and disconnects power transmission between the small diameter sun gear 15 and the turbine shaft 13. A first brake device 23 is arranged radially outward of the second clutch device 21. This first brake device 23 is a band brake, and includes a brake drum 23-1 connected to the large-diameter sun gear 16 and a brake band 23-1 attached to the brake drum.
2. A third clutch device 24 is disposed radially outward of the first clutch device 20 and on the side of the first brake device 23, and this third clutch device 24 is used for reverse driving. The clutch is
Through the brake drum 23-1 of the first brake device 23 - the enlarged diameter sangya 16 and the turbine shirt 1-1
The power transmission is interrupted between 3 and 3.

Radially outward of the planetary gear unit 14,
A second brake device 25 is arranged to engage and disengage the carrier 14a of the planetary gear unit 14 and the case 10a of the transmission gear mechanism 10. A second one-way clutch device 26 is arranged between the first and second brake devices 23, 25 in parallel with the second brake device 25 for engaging and disengaging the carrier 14a and the case 10a. A fourth clutch device 27 is disposed on the side of the planetary gear unit 14 on the engine side to connect and disconnect power transmission between the carrier 14a of the planetary gear unit and the turbine shaft 13. An output gear 28 connected to the ring gear 19 is disposed on the side of the fourth clutch device 27 on the engine side, and the output gear 28 is attached to an output shaft. Further, the turbine shaft 13 is configured to be directly connected to the crankshaft 1 without the use of the torque converter 2 by means of a lock-up clutch 29 as required.

The transmission gear mechanism 10 having the structure described above has four forward speeds and one reverse speed, and includes first to fourth clutch devices 20 to 21, 24, 27, and first to second brakes. By appropriately operating the gears 23 and 25, the desired gear position can be obtained. In the above configuration, the operational relationship between each gear stage, clutch, and brake is shown in Table 1 below.

Next, a hydraulic control circuit in the automatic transmission will be explained with reference to FIG. This hydraulic control circuit includes an oil pump 100 driven by the crankshaft 1, and hydraulic oil is discharged from the pump 100 into a pressure line 101. Hydraulic oil discharged from pump 100 to pressure line 101 is guided to regulator valve 102 . The regulator valve 102 regulates the pressure of the hydraulic oil from the pump 100 by duty-controlling the opening and closing timing of the solenoid valve 102b using control signals output from the control means 200 according to the throttle pressure, throttle modulator pressure, and backup pressure. After that, the water is supplied to the select valve 103. This select valve 103 is a manual shift valve, and is manually shifted to P-N-D, 2, and Lunge, and supplies the operating pressure from the boat 9 to a predetermined boat in each range. When the select valve 103 is set to lunge, the boats 9 are the boats a, d,
When the select valve is set to the 2 range, it is communicated to boats a, c, and d. When the select valve is set to the D range, it is communicated to boats C and the select valve is set to the R range. When set, it is communicated to boat f.

The boat a of the select valve 103 is connected to the 1-2 shift valve 110, and hydraulic oil acts on the 1-2 shift valve 110 against its spring 110a. The 2-shift valve 110 is in the first speed when the 1-2 solenoid valve 110b is OFF, and is in the second speed by draining the hydraulic oil when it is ON. For example, when the select valve 103 is set to the D range, the hydraulic oil supplied from the boat a of the select valve 103 is supplied to the 1-2 solenoid valve 110b.
is supplied to the apply chamber 23a of the hydraulic servo 1Ii 23A that operates the first brake system @23 via the 1-2 shift valve 110 during a shift from the first speed to the second speed when is turned ON. Note that when the 1-2 solenoid valve 11ob is OFF in the D range, the operating pressure from the boat a bypassing the 1-2 shift valve 110 is
Clutch device ff, 20 and second clutch device 21
is supplied to achieve the first speed state. Furthermore, this 1-
The second shift valve 110 supplies the hydraulic fluid supplied from the boat e of the select valve 103 via the low pressure reducing valve 140 to the second brake device 25 during the second gear of the lunge, and at the same time supplies the hydraulic fluid to the second brake device 25. It is designed to send signal pressure.

Boat a of the select valve 103 is the 2-3 shift valve 12
0, and supplies hydraulic oil against the spring 120a of this 2-3 shift valve 120, so that this 2-3 shift valve 120 is connected to the 2-3 solenoid valve 120b when it is ON. When the hydraulic oil is drained and the second gear is activated,
When it is OFF, it is in third gear. Note that when shifting from second speed to third speed, hydraulic oil from boat C of select valve 103 is transferred to bypass valve 14.
2. Finally, it is supplied to the fourth clutch device 27 via the 2-3 timing valve 143 to engage it, and the release of the hydraulic servo device 23A for brake operation is provided via the 3-4 shift valve 130. The first brake device 23 is brought into a released state by being supplied to the chamber 23b.

The 3-4 shift valve 130 includes the 1-2 shift valve 1
Similarly to the 10 and 2-3 shift valves 120, hydraulic oil is supplied from the boat a of the select valve 103 against the spring 130a, and this 3-4 shift valve 130
3-4 solenoid valve 130b is OFF.
4th speed (OD>
The state is now set. In the third speed state, the hydraulic fluid that has passed through the 1-2 shift valve 110 is supplied to the apply chamber 23a of the hydraulic servo device 23A for brake operation without going through an orifice, and the hydraulic fluid that has passed through the 1-2 shift valve 110 is supplied to the apply chamber 23a of the hydraulic servo device 23A for brake operation. Hydraulic oil from boat a of the bypassed select valve 103 passes through the 3-4 shift valve 130 and the coasting bypass valve 144 to the first. A second clutch device 20.21 is supplied. 3-4 above
When the solenoid valve 130t) is turned on and the hydraulic oil is drained, a shift operation from third speed to fourth speed is performed. That is, the hydraulic oil that has passed through the 1-2 shift valve 110 is supplied to the apply chamber 23a of the hydraulic servo device 23A for brake operation, and at the same time, the release chamber 23b of the hydraulic servo device 23A is drained and the first When the brake device 23 is engaged, the second clutch device 2
The hydraulic oil acting on the second clutch device 21 is also drained and the second clutch device 21 is released.

When the select valve 1.3 is set to lunge, the low pressure reducing valve 140 receives hydraulic oil from the boat e of the select valve 103, and reduces the pressure of this hydraulic oil by self-pressure regulation. The hydraulic fluid is supplied to the shift valve 110, and in the first speed state, this hydraulic fluid passes through the 1-2 shift valve 110 and is transferred to the second shift valve 110.
It is supplied to the brake device 25. In this way, the low pressure reducing valve 140 reduces the pressure of the hydraulic fluid, thereby alleviating the shock during gear shifting.

The above-mentioned 2-3 timing valve 143 operates from the second speed to the third speed.
This is to alleviate the shock that occurs when shifting to a higher speed. That is, especially when the accelerator is momentarily returned to the low opening when the accelerator opening is small, the fourth clutch device 27
If it is fastened suddenly, it is easy to feel a shock. For this reason, 2-
3 timing valve 143 to 2-3 accumulator 1
48 while regulating the pressure of the hydraulic oil through the fourth clutch device 27.
By supplying the gear to the lock, the slip time during engagement is lengthened when the axle distance is small, and controlled to be short when the axle gap is wide.

In order to reduce the impact when shifting from 3rd speed to 2nd speed according to the throttle opening, 3-2 timing valve 1
50 are provided. This 3-2 timing valve 1
50, a throttle modulator pressure acts against the spring force, and when the modulator pressure is higher than the spring force, it passes through the orifice, and when it is lower, it is bypassed and drained. This is because when the modulator pressure is high, the throttle opening is large and the engine speed is high, so draining through the orifice slows down the release of the release pressure of the hydraulic servo device 23A for brake operation.

In other words, by delaying the engagement of the first brake device 23, sudden engagement is prevented and the impact is alleviated.

In addition, the pressure line 101 is connected to a predetermined line pressure (for example, 5 to 9/cd) even when the discharge pressure of the solenoid valve 102 which is duty-controlled by the control means 200 becomes O. constant pressure valve 1
47 are provided.

This constant pressure valve 147 is controlled by a solenoid valve 147b.

Further, a lock-up control valve 151 is provided in the hydraulic oil path of the lock-up clutch 29.
In this lock-up control valve 151, hydraulic pressure acts against the spring force plus the operating pressure of the first clutch device 20. By draining the hydraulic oil while the lock-up solenoid 151b is ON, the supply of hydraulic oil is switched from the release chamber side to the apply chamber side, the release chamber pressure is drained, and the lock-up is turned ON. .

Each of the above solenoid valves 102b, 110b, 120b, 1
30b, 147b, and 151b are configured to be controlled by a control circuit 200 consisting of a microcomputer or the like according to the operating state of the vehicle and engine. That is, the control circuit 200 at least receives a turbine rotation speed signal 201 from a turbine sensor, a throttle inter-throttle signal 8-202 from a throttle opening sensor, a selection signal 203 from a range selection sensor, a vehicle speed signal 204 from a vehicle speed sensor, etc. is input, and when a shift is required based on a predetermined shift pattern, a shift up signal and a shift down signal are output to each of the solenoid valves 110b, 120b, and 130b to perform shift control at a predetermined timing. That's what I do.

In addition, the control means 200 is provided with a mechanism for controlling one friction member (the first clutch 20) while maintaining the engaged state of the other friction member, for example, when shifting up the gear from the first gear to the second gear. a speed change IT that performs a speed change operation by shifting the friction part (first brake 23) from a released state to an engaged state;
'+, the regulator valve 102 sends a control signal to reduce the hydraulic oil line pressure for a predetermined time within a range sufficient to maintain the fastened state of the other friction member (23);
A speed change control section 205 is provided that outputs an output to the solenoid valve 102b.

The coefficient of dynamic friction of the friction plates of the above-mentioned friction member is tJ8 smaller than the coefficient of static friction, and since a large static friction acts on a pair of friction plates in a connected state, it is assumed that the line pressure of the hydraulic oil is reduced. However, the friction plate will not slip. When shifting from the first gear to the second gear, as shown in FIG. However, by maintaining this pressure PG above the dynamic friction limit pressure of the friction plate 12, it is possible to prevent the friction plate of the first clutch device 20 from slipping. Furthermore, by decreasing the line pressure of the hydraulic oil as described above, the line pressure of the hydraulic oil can be quickly raised to the pressure PO when the first plagier device 23 is fastened. By maintaining this state of pressure Po for a predetermined period of time, the first brake device 23 is brought into a semi-engaged state, and then the line pressure is gradually increased to prevent the first brake device 23 from causing a shift shock.
can be concluded.

In this way, since the shift from the first gear to the second gear is controlled while controlling the line pressure of the hydraulic oil by the control signal output from the shift control section 205 of the control means 200, the above-mentioned gear shift can be performed without providing an accumulator. It is possible to prevent a shift shock from occurring when the 1 brake device 23 is shifted to the engaged state at a predetermined timing, and the configuration of the hydraulic control circuit can be simplified. In addition, in order to reliably maintain the engaged state of the first clutch device @ 20 and shift the first brake to the engaged state at a predetermined timing during the shift, the static friction coefficient of the friction plate of the first clutch device 20 must be adjusted. It is desirable to use a member in which the coefficient of friction is three times or more the coefficient of dynamic friction, and the difference between the coefficient of static friction and the coefficient of dynamic friction is large.

(Effects of the Invention) As described above, the present invention provides a method for shifting gears when a gear shifting operation is performed by shifting one friction member from a released state to a engaged state while maintaining the engaged state of the other friction member. Since the line pressure of the hydraulic oil is reduced over a predetermined time within a range sufficient to maintain the fastened state of one friction member by a control signal output from the control unit, the other friction member can be operated without providing an accumulator. It is possible to perform a gear shift operation at a predetermined timing while appropriately controlling the line pressure of hydraulic oil to the friction member. Therefore, while simplifying the structure of the hydraulic control circuit as much as possible,
This has the effect of effectively preventing a shift shock from occurring at the shift port 4.

[Brief Description of the Drawings] Fig. 1 is a schematic diagram showing the basic configuration of an automatic transmission equipped with a control device according to the present invention, Fig. 2 is a hydraulic control circuit diagram showing an embodiment of the control device, and Fig. 3 FIG. 2 is an explanatory diagram showing the pressure of hydraulic oil during a gear shift operation. 1... Output shaft, 2... Torque converter, 10...
・Speed gear mechanism, 20... First clutch neck (one friction member), 23... First brake ((1!! side friction member), 102b, 106b, 120b, 130b,
147b, 151b... Solenoid valve, 200...
Control means, 205...speed change control section

Claims (1)

[Claims] 1. A torque converter connected to the output shaft of the engine, a speed change gear mechanism disposed on the output side of the torque converter, and a plurality of friction members that perform a speed change operation by switching the power transmission path of the speed change gear mechanism; A control device for an automatic transmission, comprising a solenoid valve that controls the supply and discharge of hydraulic oil to and from the friction member, and a control means that controls the operation of the solenoid valve, maintaining the engaged state of one of the friction members. During gear shifting, the line pressure of the hydraulic oil is maintained within a range sufficient to maintain the engaged state of one friction member for a predetermined period of time during gear shifting by shifting the other friction member from the released state to the engaged state. 1. A control device for an automatic transmission, comprising a shift control section that outputs a control signal to reduce the speed.