JPH0583769B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a hydraulic pressure control device for a frictional engagement device. More specifically, the present invention relates to a hydraulic pressure control device for a friction engagement device of a brake device or a clutch device used in a transmission such as an automatic transmission.

[Conventional technology]

Automatic transmissions installed in automobiles and other vehicles generally use brake devices and clutch devices formed by frictional engagement devices (Japanese Patent Publication No. 51-10315).
issue).

The frictional engagement device is pressed by a piston, and the piston is slidably fitted into the cylinder. A chamber is formed between the cylinder and the pitton, and when hydraulic pressure is supplied to the chamber, the piston is actuated and the frictional engagement device is brought into engagement.

By the way, this type of frictional engagement device is placed in a frictional engagement state in order to establish a predetermined speed change state, and the actuation of the piston to the worn engagement state quickly closes the clearance. In this way, it is generally preferable to bring the frictional engagement device into the engaged state to complete the speed change operation, and then maintain the frictional engagement state with a strong pressing force.

In order to achieve this preferred operation, the chambers for actuating the piston are divided into a first chamber and a second chamber.
A system has been proposed in which the chamber is divided into two chambers, and hydraulic pressure is supplied from the first chamber to the second chamber (Utility Model Publication No. 54-4592).

In the technique described in this publication, the first chamber is formed as a small-volume annular chamber at a radially inner position, and the second chamber is formed as a large-capacity annular chamber at a radially outer position. . A supply oil passage through which hydraulic pressure is supplied is connected to the first chamber, and a communication passage with a small hole is formed between the first chamber and the second chamber.
Therefore, the hydraulic pressure is first supplied to the first chamber through the supply passage, and the hydraulic pressure supplied to the first chamber is supplied to the second chamber through the communication passage. Therefore, the piston is first quickly operated to close the clearance of the friction engagement device by the hydraulic pressure supplied to the first chamber with a small capacity, and then the hydraulic pressure is supplied to the second chamber with a large capacity. Hydraulic pressure is also applied to maintain the engaged state with a strong pressing force.

[Problem to be solved by the invention]

By the way, when the above-mentioned frictional engagement device is released from operation, the working hydraulic pressure of the first chamber is discharged to the supply oil path, and then the working hydraulic pressure of the second chamber is returned to the first chamber through the communication path. , the return operation of the piston is completed and the operation is released by exhausting the pressure from the first chamber to the supply oil path.

However, at this time, since the communication passage through which the hydraulic pressure is returned from the second chamber to the first chamber is formed as a small hole or a narrow gap,
The hydraulic pressure of the second chamber was not discharged smoothly, which caused a problem in that the return operation of the piston was delayed. For example, when the oil temperature is low, the viscosity of the oil is high, so the resistance passing through the communication path of the small holes is large and the return of the oil pressure is slow. Furthermore, even at high rotation speeds, the centrifugal force acts strongly, which sometimes slows down the return of hydraulic pressure.

Note that the communication path between the first chamber and the second chamber has an orifice in order to delay the supply of hydraulic pressure from the first chamber to the second chamber during operation and quickly increase the pressure in the first chamber. Therefore, the above-mentioned inconvenience occurs when the operation is released.

In addition, there are pistons that are equipped with a check ball to eliminate residual pressure in the chamber (for example, Japanese Patent Publication No. 51-10315, Japanese Unexamined Patent Publication No. 48
-27146, Figures 1 to 3).

However, this check ball is able to open due to centrifugal force and remove the residual oil pressure inside the chamber to the outside of the chamber, and only when the residual oil pressure inside the chamber is removed and drops below the centrifugal force. Since the valve can be opened, it has the effect of reducing the residual oil pressure after the return operation of the piston is completed, but it is not effective in promoting the return operation of the piston itself. As described, the disadvantage of delayed piston return operation remained.

Therefore, an object of the present invention is to provide a structure that quickly eliminates the hydraulic pressure in the second chamber, thereby eliminating the delay in the return operation of the piston.

[Means to solve the problem]

In order to solve the above-mentioned problems, the present invention takes the following measures.

That is, a piston that operates the frictional engagement device is slidably fitted into a cylinder, and hydraulic pressure is supplied between the piston and the cylinder to form a first chamber and a second chamber that operate the piston. A supply oil passage through which hydraulic pressure is supplied is connected to the first chamber, and
A communication passage is provided between the first chamber and the second chamber, and a frictional engagement is provided in which the hydraulic pressure supplied to the first chamber through the supply oil passage is supplied to the second chamber through the communication passage. In the hydraulic pressure control device of the device, a drain passage is provided that bypasses the first chamber and communicates the second chamber with the supply oil passage, and the drain passage receives the hydraulic pressure from the second chamber in the valve opening direction. A check valve is disposed so as to be received by the valve and to allow the flow of hydraulic oil from the second chamber toward the supply oil path and to prevent the flow of hydraulic oil from the supply oil path toward the second chamber. We are taking measures that are characterized by:

[Effect]

The above means works as follows.

During frictional engagement operation, the flow of hydraulic oil from the supply oil passage to the second chamber via the drain passage is blocked by the check valve, so hydraulic pressure is first supplied from the supply oil passage to the first chamber. As a result, the pressure in the first chamber quickly increases, and the piston quickly begins to move.

Subsequently, hydraulic pressure is supplied from the first chamber to the second chamber via the communication path, and the engaged state of the friction engagement device is maintained at a strong pressing force by the hydraulic pressure of the first and second chambers. Ru.

When the frictional engagement operation is released, the check valve receiving the working oil pressure of the second chamber immediately opens as the working oil pressure on the supply oil path side decreases, and the check valve receiving the working oil pressure of the second chamber immediately opens.
Hydraulic oil is allowed to flow from the chamber to the supply oil path via the drain passage.

Therefore, a part of the working pressure of the second chamber is exhausted from the communication passage through the first chamber, but most of it bypasses the first chamber and is discharged without being subjected to resistance from the communication passage. Pressure is immediately exhausted from the drain passage, eliminating the piston return delay.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIGS. 1 and 2 show an embodiment of a hydraulic pressure control device for a frictional engagement device according to the present invention. This embodiment shows a case where the frictional engagement device is a clutch device.

A piston 12 is slidably fitted into the cylinder 10. Cylinder 10 is coupled to rotating shaft 40 . The cylinder 10 is provided with a partition part 14, and a first chamber 16 and a second chamber 18 are formed between the cylinder 10 and the piston 12, separated by the partition part 14. The first chamber 16 is located radially inward and is formed into a small volume annular chamber. The second chamber 18 is located radially outward and is formed into a large volume annular chamber.

The rotating shaft 40 has hydraulic pressure supply oil passages 42 and 44.
is provided, and a supply oil passage 44 is coupled to the first chamber 16 . Further, a communication path 20 is provided in the partition portion 14 of the cylinder 10,
The first chamber 16 and the second chamber 18 are communicated with each other. The communication path 20 is formed in a small hole that serves as an orifice. Further, a drain passage 22 is provided in the partition portion 14. Drain passage 22
is provided between the second chamber 18 and the supply oil passage 42.

A check ball 24 as a check valve is disposed in the drain passage 22. The check ball 24 is arranged to allow flow from the second chamber 18 in the direction of the supply oil path 42, but to prevent flow from the supply oil path 42 in the direction of the second chamber 18. In this embodiment, as shown in FIG. 1, the check ball closes due to the difference in pressure receiving area before and after the check ball.
If necessary, a spring or the like may be added to bias the valve in the valve closing direction.

The check ball 24 is preferably provided as far inward as possible in the radial direction to prevent centrifugal force from acting as much as possible.

Further, the check ball 24 is preferably arranged so that even when centrifugal force is applied, the check ball 24 does not act in a direction to close the drain passage 22 due to the centrifugal force. In addition to the arrangement as shown in Fig. 1, the check ball 24 is arranged at an angle as shown in Fig. 3, and the centrifugal force acting on the check ball 24 (arrow in Fig. 3)
Alternatively, the drain passage 22 may be opened.

A spring seat 46 is fixedly attached to the tip portion 40a of the rotating shaft 40. A return spring 4 formed of a coil spring is provided between this spring seat 46 and a spring seat 56 seated on the piston 12.
8 is interposed. This return spring 4
8 always urges the piston 12 in the left direction as seen in FIG. Therefore, when hydraulic pressure is not supplied to the first chamber 16 and the second chamber 18, the piston 12 is in a position where it is in contact with the side wall 10a of the cylinder 10 as shown in FIG. 12 is in the returned state.

In addition, in FIG. 1, the seal rings 26 and 28 attached to the piston 12 and the partition portion 1
A seal ring 30 attached to the chamber 4 ensures an oil-tight state of the first chamber 16 and the second chamber 18, and prevents the hydraulic pressure from leaking to the other chambers.

The friction engagement device 32 is formed by a large number of friction materials 34 and disk plates 36 arranged alternately. That is, it is formed in a multi-plate format. As is well known, each friction member 34 is attached to the hub 52 of another rotation transmitting member 50 at its inner peripheral portion by claw coupling, so that the friction member 34 is integral with the hub 52 in the rotational direction but movable in the axial direction. Similarly, each disk plate 36 has an outer circumferential wall 1 of the cylinder 10 at its outer circumference.
It is attached to 0b by a claw connection so that it is integral in the rotational direction but movable in the axial direction.

The frictional engagement device 32 is connected to the outer peripheral wall 1 of the cylinder 10.
It is stopped by a snap spring 54 attached to 0b to prevent it from slipping out. Also,
A disk spring 38 is disposed on the side of the friction engagement device 32 that comes into contact with the piston 12.

The frictional engagement device 32 is pressed by the piston 12, and when a frictional force is generated between the disk plate 36 and the friction material 34, a frictional engagement state is established, and the rotation shaft 42 and the rotation transmission member 50 are brought into a rotation transmission state. Become. Then, when the piston 12 is returned, the frictional engagement state of the frictional engagement device 32 is released, and the rotation shaft 40 and the rotation transmission member 50 are disconnected.

Next, the effect will be explained.

First, the supply and exhaust of hydraulic pressure to the second chamber 18 are performed as follows.

When hydraulic pressure is supplied to the second chamber 18, the hydraulic pressure from the supply passage 42 acts on the check ball in the valve closing direction, and the drain passage 22
Since the flow of hydraulic fluid toward the second chamber 18 via the check ball 24 is blocked,
It is supplied from the first chamber 16 only by the communication passage 20.

Conversely, when the pressure is exhausted from the second chamber 18, as the working pressure of the supply passage 42 decreases,
The check ball 24 is put into a flowing state by the hydraulic pressure from the second chamber 18, and the drain passage 22 and the communication passage 20 are used to discharge pressure.

Therefore, when the frictional engagement device 32 is brought into the frictional engagement state, hydraulic pressure is supplied to the first chamber 16 through the supply oil passages 42 and 44, and further from the first chamber 16 through the communication passage 20. A second chamber is supplied. As a result, the piston 12
is performed, and the frictional engagement device 32 is brought into a frictional engagement state.

In detail, the actuation of the piston 12 is performed because hydraulic pressure is first supplied to the first chamber 16.
This is done by hydraulic pressure supplied to the first chamber 16. Since the first chamber 16 has a small capacity, a large stroke operation is quickly performed with a small amount of hydraulic pressure, and this operation closes the clearance of the friction engagement device 32, resulting in a friction engagement state that achieves a gear shift state. do.

Next, when the second chamber 18 is filled with the hydraulic pressure supplied through the communication passage 20, the piston 12 is filled with the second chamber 18.
Pressurization of the working oil pressure is also applied, and the frictional engagement state of the frictional engagement device 32 is maintained with a strong pressing force, so that the frictional engagement device 32 is in a complete frictional engagement state without slipping.

The timing of transition of the frictional engagement device 32 from the frictional engagement state that achieves the speed change state to the complete frictional engagement state is determined by the size of the communication path 20. The communication path 20 is generally a small hole, and the transition timing is suitable. This also helps to reduce the shift shock.

When the frictional engagement state of the frictional engagement device 32 is released, the hydraulic pressure in the supply oil passage 42 is set to a discharged pressure state, and the check ball 24 is immediately opened by the hydraulic pressure in the second chamber. Then, the exhaust pressure of the working hydraulic pressure in the first chamber 16 is released from the supply oil path 44.
and 42 , and the hydraulic pressure in the second chamber 18 is discharged directly to the supply oil passage 42 through the drain passage 22 . That is, the first chamber 1
The hydraulic pressure in the second chamber 18 and the hydraulic pressure in the second chamber 18 are discharged simultaneously, and the hydraulic pressure in the second chamber 18 is discharged more quickly than in the case where the hydraulic pressure in the second chamber 18 is discharged only by the conventional communication path 20. It will be done.

Therefore, even when the oil has high viscosity at low oil temperature or when centrifugal force acts strongly at high rotation, the hydraulic pressure in the second chamber 18 is removed relatively quickly.

As a result, the return operation of the piston 12 is quickly performed, and there is no delay as in the conventional case.

Although the present invention has been described above with reference to specific illustrated embodiments, the present invention is not limited to such embodiments, and various other embodiments are possible within the scope of the present invention.

For example, in the above-described embodiment, the communication passage 20 was provided in the partition part 14 of the cylinder 10, but the communication passage 20 was provided in the partition part 14 of the cylinder 10.
It can also be provided in 2. Moreover, it can also be provided between the partition part 14 and the sliding part of the piston 12.

Furthermore, although the check valve used in the above embodiment was the check ball 24, various other one-way valves may be used.

〔Effect of the invention〕

As described above, the present invention is provided with a drain passage that bypasses the first chamber and communicates the second chamber with the supply oil passage, and the drain passage receives the hydraulic pressure from the second chamber in the valve opening direction. A check valve is disposed to receive the hydraulic oil from the second chamber and to allow the flow of hydraulic oil from the second chamber toward the supply oil path and to prevent the flow from the supply oil path toward the second chamber. When the hydraulic pressure in the second chamber is exhausted, the check valve opens immediately, and most of the hydraulic pressure is discharged directly to the supply oil path without passing through the first chamber.

Therefore, even when the oil temperature is low and the oil is highly viscous, or when the centrifugal force is strong at high rotations,
The pressure is removed quickly, and as a result, the return operation of the piston is performed smoothly without any delay. Moreover, when the frictional engagement device engages, the hydraulic pressure is supplied from the first chamber to the second chamber only through the communication path, as before, so that the frictional engagement can be operated quickly as before. It can be carried out.

Additionally, the present applicant has proposed that a drain passage provided with a check valve as in the present invention be provided between the second chamber and the first chamber as a means for quickly discharging the working hydraulic pressure of the second chamber. However, in the case of the present invention, most of the exhaust pressure from the second chamber is directly transmitted without passing through the first chamber. Because it is done, it is done so quickly.

[Brief explanation of drawings]

FIGS. 1 and 2 show an embodiment of the hydraulic pressure control device for a frictional engagement device according to the present invention.
The figure is a sectional view, and FIG. 2 is a side view showing the cylinder portion. FIG. 3 is a sectional view showing a modification of the check ball. Explanation of symbols, 10...Cylinder, 12...Piston, 16...First chamber, 18...Second chamber, 20...Communication passage, 22...Drain passage, 24...Check ball (check valve) ),
32... Frictional engagement device, 42, 44... Supply oil path.

Claims (1)

[Claims] 1. A piston that operates a frictional engagement device is slidably fitted into a cylinder, and a first chamber and a first chamber that operate the piston are supplied with hydraulic pressure between the piston and the cylinder. 2 chambers are formed, the first chamber is connected to a supply oil passage through which hydraulic pressure is supplied, and the first
A communication passage is provided between the chamber and the second chamber, and the hydraulic pressure supplied to the first chamber through the supply oil passage is supplied to the second chamber through the communication passage. In the hydraulic pressure control device, a drain passage is provided that bypasses the first chamber and communicates the second chamber with the supply oil passage, and the drain passage receives hydraulic pressure from the second chamber in a valve opening direction. The present invention is characterized in that a check valve is disposed to allow the flow of hydraulic oil from the second chamber in the direction of the supply oil path and to prevent the flow of hydraulic oil from the supply oil path in the direction of the second chamber. Hydraulic control device for frictional engagement device.