JPS6232131Y2 - - Google Patents

Description

[Detailed description of the invention] This invention is used in a brake device equipped with a hydraulic pump, and when the hydraulic pump is operating normally, it receives pressure fluid from the hydraulic pump and applies it to the brake pedal. This hydraulic system supplies hydraulic pressure to the brake cylinder according to the pedal force applied, and when the hydraulic pump fails and no hydraulic pressure is generated, the hydraulic fluid stored in the accumulator is controlled and supplied to the brake cylinder. Regarding brake valves.

Conventionally, this type of brake valve has a spool that is slidably inserted into a hole drilled in the valve body and connects a pressure chamber connected to a brake cylinder to a hydraulic pump and a liquid tank, and a brake pedal. a plunger that moves in response to a pushing force from the pressure chamber and operates the spool; a reaction force member that receives hydraulic pressure in the pressure chamber and transmits a reaction force corresponding to the hydraulic pressure in the pressure chamber to the plunger; It is known that the pressure pump is equipped with an emergency valve that can connect the accumulator to the pressure chamber in the event that hydraulic pressure is no longer generated due to a failure of the pressure pump.

By the way, in the conventional type, a reaction force surface is formed on one end surface of the spool, and the emergency valve is operated by the spool, so that the pushing force of the plunger is applied to the spool directly or via a pushing force transmission spring. Not only does this act, but also a reaction force corresponding to the hydraulic pressure in the pressure chamber acts, resulting in an extremely large force acting on the spool, and a large biasing force is applied to the spool. The biasing force is applied, causing the spool to become lopsided with respect to the spool hole, which not only increases liquid leakage, but also degrades the durability of the spool.

The present invention was made in view of the above-mentioned problems, and aims to provide a hydraulic brake valve that eliminates the application of mechanical force to the spool and improves the durability of the spool. The feature is that the reaction member is made separate from the spool, and the spool, the reaction member, and the plunger are arranged in this order within the valve body, and the reaction member and the spool the pressure chamber is defined in the reaction force member, an operation member for opening and closing the emergency valve is formed on the reaction force member, a back chamber connected to the pressure chamber is defined on the opposite side of the spool from the plunger side, and A spring for biasing the spool toward the reaction member is disposed in the back chamber.

That is, with the above configuration, when the pushing force of the plunger is increased to increase the hydraulic pressure in the pressure chamber, the pushing force is transmitted to the spool via the pressure member, but the pressure is increased. The hydraulic pressure in the same chamber as the chamber is led to the back chamber, and the hydraulic pressure acting on the spool is canceled out, and when the pushing force of the plunger and the hydraulic pressure in the pressure chamber acting on the reaction member are balanced, the force acting on the spool is reduced. is only the biasing force of the spring. Further, since the emergency valve is opened and closed independently of the spool, no excessive force is applied to the spool, so that the seat surface of the spool will not wear unevenly due to biasing force. In addition, since the reaction force member is configured separately from the spool, the pressure receiving area of the reaction force member can be freely set regardless of the spool diameter, and the hydraulic pressure generated in the pressure chamber in response to the brake pedal force can be freely set. can do.

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

In the figure, the brake valve, indicated as a whole by 1, has a valve body 2, and a stepped hole 3 is bored in the valve body 2, the diameter of which gradually increases toward the right in the figure. . The small diameter part 4 of the stepped hole 3 is provided with two annular grooves 5 and 6, the annular groove 5 is connected to the liquid tank 8 through the outlet 7, and the annular groove 6 is connected to the liquid tank 8 through the input port 9. It is connected to a pressure pump 10. Further, the small diameter portion 4 communicates with a delivery port 11, and the delivery port 11 is connected to a power steering device 12 that reduces steering force, and then connected to a liquid tank 8. The medium diameter portion 13 of the stepped hole 3 is connected to a brake cylinder 15 of the vehicle via an output port 14 and communicates with a hole 17 formed in the valve body 2 via a through hole 16 .
A ball valve 21 pressed against a valve seat 20 by a valve spring 19 is disposed in a connecting member 18 screwed into the hole 17, and the inside of the hole 17 is composed of a valve seat 20 and a ball valve 21. It is connected to an accumulator 24 via an emergency valve 22 and a connection port 23. Stepped hole 3
At the left end of the large diameter portion 25, there is a seal member 26 on the outer periphery.
The annular member 27 equipped with the
The plunger guide member 29 is screwed onto the threaded portion of the plunger guide member 29 and has a hole 28 inside.

The spool 30 is slidably inserted into the small diameter part 4 of the stepped hole 3, and has a reduced diameter part 31, a groove 32,
33 and also radially and axially bore 34
and 35 are provided, and a back chamber 36 is formed between the closing wall of the stepped hole 3 and its left end surface. A seal cup 37 is attached to the outer periphery of the right end of the spool 30, and the outer periphery lip of this seal cup 37 is
When the sleeve 30 is in the right position, that is, in the position shown in the figure, a gap is formed between the inclined surface 38 formed at the boundary between the small diameter part 4 and the medium diameter part 13. 39
is a spring disposed within the back chamber 36 and urges the spool 30 to the right.

The reaction member 40 is movably disposed within the medium diameter portion 13 of the stepped hole 3 and defines a pressure chamber 41 between it and the right end of the spool 30. A discharge valve 45 is movably disposed in a recess 42 formed in the reaction member 40 and is pressed leftward by a valve spring 43 and whose leftward position is restricted by a stopper 44. The discharge valve 45 can be seated at the right end opening of the inner hole 35 provided in the spool 30. Reaction force member 40
The outer circumferential surface of the slanted surface 47 that forms a reduced diameter portion 46 and a valve operating portion is formed, and when the reaction member 40 is pushed to the right by a spring 48 and is in the position shown in the figure, The rod 49 that opens and closes the valve 22 engages the reduced diameter portion 46 to keep the emergency valve 22 in the closed position, and the rod 49 that moves the reaction member 40 to the left is pushed up by the inclined surface 47 to open the emergency valve 22. . The right extension 50 of the reaction member 40 is connected to the annular member 2
7 in a slidable manner and extends into the hole 28 of the guide member 29, and the cross-sectional area of the extension portion 50 forms a pressure receiving area. Note that the through hole 51
is for communicating the pressure chamber 41 and the chamber on the right side of the reaction force member 40.

A spring receiver 52 in contact with the right end of the extension part 50 of the reaction member 40 and a bolt 53 screwed into the extension part 50
When the distance between the first spring 55, whose spring tension is set to a predetermined value, and the spring receiver 54 whose movement amount to the right is limited by the spring receiver 54, and the distance between the first spring 55, which has a spring tension set to a predetermined value, and the two spring receivers 52 and 54, becomes less than a predetermined value. A second spring 56 is arranged to be compressed and the guide member 29
The plunger 57 is slidably fitted into the hole 28 of the
Until the amount of movement of the plunger 57 reaches a predetermined value, the increase in the spring force with respect to the amount of movement of the plunger 57 is made small;
When the amount of movement of the plunger 57 exceeds the predetermined value, the spring force increases with respect to the amount of movement.

59 is a push rod that transmits a pushing force applied by a brake pedal (not shown) to the plunger 57, 60 is a stopper for the plunger 57, and 61 is a dust seal.

The effects of the embodiment configured as described above will be explained below.

When the hydraulic pump 10 is normal and the brake is not applied, each component of the brake valve 1 is in the position shown in the figure, and the fluid supplied from the hydraulic pump 10 to the input port 9 flows through the small diameter portion 4. annular groove 6,
The liquid is delivered to the delivery port 11 through the groove 32 of the spool 30, and further circulated to the liquid tank 8 via the power steering device 12. At the same time, the pressure chamber 41 passes through the gap between the seal cup 37 and the inclined surface 38, the groove 33, the inner holes 34 and 35, the back chamber 36, the reduced diameter part 31 of the spool, the annular groove 5, and the discharge port 7, and then the liquid tank 8. The hydraulic pressure is zero, and therefore, no hydraulic pressure is supplied to the brake cylinder 15. Further, the lower end of the rod 49 that opens and closes the emergency valve 22 is in contact with the reduced diameter portion 46 of the reaction force member 40,
Emergency valve 22 is closed.

To apply the brakes in this state, when the brake pedal is depressed, the plunger 57 moves to the left, so the reaction member 40 is pushed via the spring 55 or the springs 55 and 56, and is pushed against the spring 48. Move left. Now, spool 3
0 moves to the left against the spring 39. When the spool 30 moves to the left, the annular groove 5 communicating with the discharge port 7 and the reduced diameter portion 31 of the spool 30 are first cut off to cut off communication between the pressure chamber 41 and the liquid tank 8, and then the spool 30 The groove 33 and the annular groove 6 communicating with the input port 9 are opened, and the communication between the annular groove 6 and the groove 32 communicating with the outlet 11 is narrowed. Therefore, a hydraulic pressure corresponding to the throttle amount is generated at the discharge side of the hydraulic pump 10, that is, at the input port 9. Therefore, the pressure fluid passes through the gap between the seal cup 37 and the inclined surface 38 or deforms into the seal cup 37 and flows into the pressure chamber 41, and this pressure fluid is supplied to the brake cylinder 15 through the output port 14. Brake is applied. When hydraulic pressure is generated in the pressure chamber 41, the reaction force member 40 is pushed to the right by the hydraulic pressure in the pressure chamber 41, and the spring 55 or the springs 55, 5
As it moves against the spring force of 6, the spool 30
moves to the right to reduce the amount of constriction between the annular groove 6 and the groove 32. Then, the hydraulic pressure that pushes the reaction force member 40 of the pressure chamber 41 to the right, that is, the product of the hydraulic pressure of the pressure chamber 41 and the cross-sectional area of the right extension 50, is applied to the plunger 57 applied by the brake pedal. When the pushing force is balanced, the spool 30 is in the balanced position. That is,
The hydraulic pressure in the pressure chamber 41 is controlled in proportion to the pushing force applied to the plunger 57.

Note that the value of the hydraulic pressure in the pressure chamber 41 with respect to the pushing force applied to the plunger 57 can be freely set by changing the pressure receiving area of the reaction force member 40, that is, the cross-sectional area of the right extension part 50. can.

Also, during this control, the discharge liquid pressure of the hydraulic pump 10 is supplied to the pressure chamber 41 via the groove 33 and also to the back chamber 36 via the inner holes 34 and 35. The hydraulic pressure is always maintained at the same pressure as the hydraulic pressure in the pressure chamber 41. Therefore, the mechanical force acting on the spool 30 is substantially only the pressing force by the spring 39, and no biased weight acts on the spool 30.

When the pedal force applied to the brake pedal is removed to release the brake, the plunger 57, the reaction member 40 and the spool 30 are moved by the springs 55, 5.
6. The spring 48 and the spring 39 push the spring 48 and the spring 39 to the right and move, and return to the position shown in the figure.
When the spool 30 returns to the position shown in the figure, the annular groove 6 and the groove 33 are cut off, and the annular groove 5 is connected to the reduced diameter part 31.
Since the seal cup 37 of the pressure chamber 41 communicates with
Gap between and inclined surface 38, groove 33, inner hole 34, 3
5. It communicates with the liquid tank 8 through the back chamber 36 and the discharge port 7, and the liquid pressure in the pressure chamber 41 is released. Therefore, the hydraulic pressure in the brake cylinder 15 is also released, and the brake is relaxed.

In the above operation, the amount of movement of the reaction member 40 is limited to the amount necessary to cut off the communication between the groove 32 of the spool 30 and the annular groove 6 that communicates with the input port 9. The lower end of the rod 49 that opens and closes only slides on the reduced diameter portion 46 of the reaction force member 40 and does not engage with the inclined surface 47.
2 is kept closed. Furthermore, when the liquid pressure in the pressure chamber 41 becomes higher than the storage pressure in the accumulator 24, the pressure liquid in the pressure chamber 41 displaces the ball valve 21 from the valve seat 20 and flows into the accumulator 24, replenishing the stored pressure liquid. .

Next, a description will be given of the effect when the hydraulic pump 10 fails and no hydraulic pressure is generated.

When the brake pedal is depressed in this state, the reaction member 40 and the spool 30 move toward the plunger 57.
As a result, the left end of the spool 30 abuts the bottom wall of the stepped hole 3. Then, the outer lip of the seal cup 37 comes into sealing engagement with the inner wall of the small diameter portion 4, cutting off communication between the groove 33 and the pressure chamber 41. At the same time, the rod 49 moves the reaction member 40
The ball valve 21 is pushed up by the inclined surface 47 of the valve seat 20, and the pressure fluid of the accumulator 24 flows into the pressure chamber 41 through the emergency valve 22 and the through hole 16, and then from the output port 14 to the brake It is supplied to the cylinder and the brake is applied. When hydraulic pressure is generated in the pressure chamber 41, the reaction force member 40 moves slightly to the right due to the hydraulic pressure, and a force pushing the reaction force member 40 to the right is transferred from the plunger 57 to the spring 5.
5 or the pushing force transmitted via the springs 55, 56, the emergency valve 22 closes and keeps the hydraulic pressure in the pressure chamber 41 constant.

When the pushing force applied to plunger 57 is removed to release the brake, plunger 57 and reaction member 40 are pushed to the right by the spring forces of springs 55, 56 and spring 48, returning to the position shown in the figure. However, since the spool 30 is pushed to the left by the hydraulic pressure in the pressure chamber 41 and is kept in the left position, the discharge valve 45 installed on the reaction member 40
is removed from the right end opening of the inner hole 35 formed in the spool 30. Therefore, the pressure liquid in the pressure chamber 41 is supplied to the back chamber 36 through the inner hole 35, the liquid pressure in the pressure chamber 41 and the back chamber 36 become the same pressure, and the spool 30 is pushed to the right by the spring 39 and moved. However, the reduced diameter portion 31 and the annular groove 5 communicate with each other, and a gap is created between the outer lip of the seal cup 37 and the inclined surface 38, and the pressure fluid in the pressure chamber 41 flows through the gap, the inner holes 34, 35, and the back. The liquid is discharged into the liquid tank 8 through the chamber 36 and the discharge port 7.

In the event of a failure of this hydraulic pump,
The spool 30 receives the hydraulic pressure of the pressure chamber 41 on its right end surface, but since the spool 30 is in contact with the bottom wall of the stepped hole 3 and does not slide, its outer peripheral surface is subject to sliding wear. There's nothing to do. Further, the emergency valve 22 is configured separately from the discharge valve 45, and
The discharge valve 45 is normally closed and opens only when the brake is loosened and the distance between the spool 30 and the reaction force member 40 exceeds a predetermined distance. Even if there is, there is no risk that the emergency valve 22 and the discharge valve 45 will open at the same time. In addition, since the rod 49 that opens and closes the emergency valve 22 is moved up and down by the inclined surface 47 provided on the reaction member 40, by changing the angle of inclination of the inclined surface 47, the emergency The opening degree of the valve 22 can be adjusted with high precision.

It should be noted that the present invention is not limited to the above-mentioned embodiments, but can be modified in many ways within the scope of its technical concept. For example, in this embodiment, the emergency valve is made up of a ball valve that is pushed up against the rod, but instead of a ball valve, the valve body is tilted so that it is lifted off the valve seat. The constructed tilt valve may be used with its legs engaging a reaction member to open the valve, and one spring may be used instead of two springs disposed between the reaction member and the plunger.
Alternatively, a rubber elastic member may be used. In addition, in this embodiment, the input port,
Although the delivery port and the discharge port are switched by the spool, if a power steering device is not required, the input port and the discharge port may be switched by the spool.

As is clear from the above explanation, according to the present invention, the extremely large force due to the pushing force from the plunger and the liquid pressure in the pressure chamber does not act on the spool, so it is not subjected to biasing force at all, and therefore the sealing surface of the spool It has excellent durability without causing uneven wear or increasing liquid leakage, and the diameter of the spool and the pressure receiving area of the reaction force member can be optimally set separately.

[Brief explanation of the drawing]

The figure is a sectional view including piping connections showing one embodiment of the present invention. 1...brake valve, 2...valve body, 3...stepped hole, 7...discharge port, 8...liquid tank, 9...input port, 10...hydraulic pump, 11...power steering device , 14... Output port, 15... Brake cylinder, 22... Emergency valve, 24... Accumulator, 30... Spool, 36... Back chamber, 39...
... Spring, 40 ... Reaction member, 41 ... Pressure chamber, 45 ... Discharge valve, 47 ... Inclined surface (valve operation part), 49 ... Rod, 57 ... Plunger.

Claims (1)

[Scope of utility model registration request] It is slidably inserted into a hole drilled in the valve body,
A spool that switches and connects a pressure chamber connected to a brake cylinder to a hydraulic pump and a liquid tank, a plunger that moves in response to pressure from a brake pedal and operates the spool, and a plunger that receives hydraulic pressure in the pressure chamber. , a reaction force member that transmits a reaction force according to the hydraulic pressure in the pressure chamber to the plunger, and an emergency member that can connect an accumulator to the pressure chamber when the hydraulic pump fails and no longer generates hydraulic pressure. In the hydraulic brake valve, the reaction force member is made separate from the spool, and the spool, the reaction member, and the plunger are respectively arranged in this order within the valve body, and the reaction force member and the plunger are arranged in this order. The pressure chamber is defined between the pressure chamber and the spool, an operating section for opening and closing the emergency valve is formed in the reaction member, and a back chamber connected to the pressure chamber is formed on the opposite side of the spool from the plunger side. A hydraulic brake valve comprising a partitioned section and a spring disposed in the back chamber to bias the spool toward the reaction member.