JPS624048Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a booster used to facilitate the operation of a brake pedal or a clutch pedal of an automobile, and particularly relates to a hydraulic booster.

2. Description of the Related Art Systems for supplying hydraulic pressure to a hydraulic booster from a hydraulic pump of a hydraulic device having a normally open control valve mechanism, such as a power steering system, are known. In this system, if the hydraulic pressure of the hydraulic booster can rise to the maximum discharge pressure of the hydraulic pump, hydraulic oil will not be supplied to hydraulic equipment such as the power steering when the pedal is strongly depressed, and this hydraulic equipment will becomes inoperable.

The above problem can be solved by attaching a relief valve to the hydraulic booster that limits its working oil pressure to a level lower than the maximum discharge oil pressure of the hydraulic pump, but simply adding a relief valve will increase the cost and increase the size. accompanied by harmful effects.

Therefore, in the present invention, the control valve mechanism of the hydraulic booster is configured to perform the relief valve function so that the valve vibration phenomenon does not occur during the relief valve function.

The present invention will be explained below by describing embodiments of the present invention based on the drawings. In FIG. 1, R is a reservoir, P is a hydraulic pump, R/V is a regulator valve, B is a hydraulic booster, M is a brake master cylinder, and P/S is a power steering.

The regulator valve RV has a valve spool 3 that is fluid-tightly and slidably fitted into the cylinder hole 2 of the main body 1. This valve spool 3 has two lands 3a,
3b, and the inside of the cylinder hole 2 is divided into a pressure chamber 5 between the land 3a and the plug 4, an annular chamber 6 between the lands 3a and 3b, and a pressure chamber 8 between the land 3b and the plug 7. The annular chamber 6 is connected from the inlet 9 of the main body 1 to the outlet of the hydraulic pump P, and the pressure chamber 5 is connected to the damping orifice 10 provided in the valve spool 3.
The hydraulic pressure of the annular chamber 6, i.e., the hydraulic pump P
The discharge hydraulic pressure is transmitted. A weak spring 11 is installed in the pressure chamber 8 to bias the valve spool 3 toward the pressure chamber 5, and the working pressure of the hydraulic booster B is transmitted to the pressure chamber 8 from a passage in the main body 1. be done. An annular groove 13 is provided which communicates with the annular chamber 6 by sliding in the direction of the pressure chamber 8 from the rest position of FIG. 1 in which the valve spool 3 abuts the plug 4. This annular groove 13 is the outlet 14 of the main body 1.
It is connected to the inlet of the power steering P/S.

The regulator valve R/V having such a structure transfers the hydraulic pressure of the pressure chamber 5, that is, the discharge hydraulic pressure of the hydraulic pump P, to the pressure chamber 8 when the power steering P/S is not activated.
Adjust the oil pressure to a level slightly higher than the oil pressure. The hydraulic pressure difference between the pressure chambers 5 and 8 is determined by the force of the spring 11.

The hydraulic booster B has a power piston 16 liquid-tightly and slidably fitted into the cylinder hole 15 of the main body 1, and a plug 17 fixed in the opening of the cylinder hole 15 in a liquid-tight and slidable manner. The input piston 18 extends therethrough. The input piston 18 is connected to a brake pedal 20 via a push rod 19, and the brake pedal depression force is controlled by the input piston 1.
8 into the main body 1. An annular groove 22 is provided on the outer periphery of the power piston 16 to which pressure oil in the annular groove 6 of the regulator valve R/V is supplied via a check valve 21. A control valve mechanism 24 is built into the power piston 16 for supplying pressure oil to the power piston operating hydraulic chamber 23 between the power piston and the plug 17, or for causing pressure oil in the hydraulic chamber 23 to flow out to the reservoir R.

To explain this control valve mechanism with reference to FIGS. 1 and 2, a hollow reaction force control piston 25 having an outer diameter slightly smaller than the outer diameter C of the large diameter portion of the input piston 18 is located near the hydraulic chamber 23 inside the power piston 16. are fitted in a fluid-tight and slidable manner, and a hollow valve member 26 for controlling the flow of pressure oil from the annular groove 22 to the hydraulic chamber 23 is fluid-tightly and slidably fitted in the center of the interior of the power piston 16. Fitted and further power piston 1
There is a plug 27 inside 6 near the master cylinder M.
are fitted in a fluid-tight manner. Reaction force control piston 25
A small-diameter end portion 18a of the input piston 18 is fluid-tightly and slidably fitted therein. Input piston 1
8 is provided with a flange 18b located between one end of the reaction force control piston 25 and a ring 29 attached to the power piston 16 with a retaining ring 28.
A stepped axial hole 30 with a large diameter inlet is provided on the small diameter end 18a side of the input piston 18, and this axial hole 30 controls the flow of pressure oil from the hydraulic chamber 23 to the reservoir R. A hollow valve member 31 is fitted therein. This valve member 31 has an axial hole 30
A damper chamber 32 is provided in the small diameter portion 31a that is liquid-tightly and slidably fitted into the small diameter portion of the axial hole 30, and in the large diameter portion of the axial hole 30.
It has a large diameter part 31b that partitions the small diameter part 3.
It is linked to the input piston 18 by a spring 33 stretched between the end surface 1a and the bottom surface of the axial hole 30 and a retaining ring 34 attached to the input piston 18. The damper chamber 32 is located in the large diameter portion 31 of the valve member 31.
It passes through the drain chamber 35 through a gap between the outer circumference b and the inner circumference of the large diameter portion of the axial hole 30. This drain chamber 3
5 is a piston 37 of the brake master cylinder M via a passage 36 provided in the power piston 16.
This hole 38 communicates with a reservoir connection port 42 through a slit 39 in the piston 37, an annular groove 40, and a hole 41 in the main body 1. A spring 43 is provided within the drain chamber 35 to bias the reaction force control piston 25 toward the hydraulic chamber 23 . This spring 43 is connected to the valve member 31 when not braking.
This is to separate the seat 44 from the valve portion 26a of the valve member 26, and to apply an appropriate actuation reaction force to the input piston 18 at the start of braking. Valve member 3
The inner passage 45 of No. 1 communicates with the hydraulic chamber 23 via the axial hole 30 and the hole 46 . The outer diameter B of the small diameter portion of the valve member 31 is set smaller than the diameter A of the seat 44. A chamber 47 between valve member 26 and plug 27 communicates with an inner passage 45 of valve member 31 via an inner passage 48 of valve member 26 . Inside this chamber 47 is a valve member 26.
A spring 49 is provided that urges the valve member 31 toward the valve member 31, and the valve member 26 has a valve portion 26b that contacts the seat 50 of the power piston 16 due to the force of the spring 49. This valve part 26b allows the chamber 4
An annular chamber 52 which is interrupted by a hole 53 communicates with the annular groove 22 .

A pressure chamber 54 is defined between the piston 37 of the brake master cylinder M and the end wall of the cylinder hole 15. This pressure chamber 54 communicates with the brake cylinder 56 of the wheel from an outlet 55 of the main body 1, and a piston return spring 57 is installed within this pressure chamber 54. The return position of piston 37 is pin 58
Defined by A valve mechanism 59 is attached to the piston 37 and is opened by engaging a pin 58 when the piston 37 returns, and the pressure chamber 54 is connected to the hole 38 by this valve mechanism 59.

Next, the operation will be explained. The drawing shows the car in an unused state, and the hydraulic pump P is not operating.

When the automobile is used, the hydraulic pump P is operated, and its discharged oil flows through the regulator valve R/V to the power steering P/s. When the steering wheel and brake pedal are not operated, the discharge oil pressure of the hydraulic pump P is adjusted to a low oil pressure value determined by the spring 11 of the regulator valve R/V.

When the brake pedal is depressed while the discharge oil pressure of the hydraulic pump P is adjusted to a low pressure as described above, the input piston 18 is pushed into the main body 1, and the sliding movement of the input piston 18 is caused by the spring 3.
3 to the valve member 31, and the valve member 31 collides with the valve portion 26a of the valve member 26 with its seat 44. This isolates the hydraulic chamber 23 from the reservoir R. As the input piston 18 continues to be pushed in, the valve member 26 is pushed by the valve member 31, and the valve portion 26b is separated from the seat 50. As a result, the low pressure oil in the annular chamber 6 of the regulator valve R/V is distributed between the check valve 21 - the annular groove 22 - the hole 53 - the annular chamber 52 - the chamber 47 - the inner passage 48 of the valve member 26 - the inner passage 45 of the valve member 31 The oil flows into the hydraulic chamber 23 through the axial hole 30 and the hole 46 in order, and the oil pressure in the hydraulic chamber 23 starts to rise. The hydraulic pressure in the hydraulic chamber 23 is in the passage 1.
2 to the pressure chamber 8 of the regulator valve R/V, and in cooperation with the spring 11 urges the valve spool 3 in the direction of the pressure chamber 5. Therefore, the regulator valve R/V increases the discharge hydraulic pressure of the hydraulic pump P as the hydraulic pressure in the hydraulic chamber 23 increases, and pressure oil continues to flow into the hydraulic chamber 23.

The hydraulic pressure in the hydraulic chamber 23 raised as described above is applied to the power piston 16, and the power piston 1
6 slides in the direction of the piston 37 and the piston 37
Push. When the piston 37 is pushed, the valve mechanism 59 closes, the pressure chamber 54 is isolated from the hole 38, and the oil in the pressure chamber 54 is pressurized and supplied to the brake cylinder 56. Further, the hydraulic pressure in the hydraulic chamber 23 acts on the input piston 18 to push it out of the main body, and also pushes the reaction force control piston 25 toward the drain chamber 24.The hydraulic pressure in the hydraulic chamber 23 causes the reaction force control piston 25 to spring up. 43, the area over which the hydraulic pressure in the hydraulic chamber 23 acts on the input piston 18 is π/4A ² and π/4(C ² − ^D2 )
The reaction force of the input piston 18 is mainly generated by the spring 43. However, when the hydraulic pressure in the hydraulic chamber 23 is higher than that, the reaction force control piston 25 is integrated with the power piston 16, and the area over which the hydraulic pressure in the hydraulic chamber 23 acts on the input piston 18 is π/4A ² and π/ 4( ^C2 − ^E2 )
The sum of input piston 1 increases compared to before.
The actuation reaction force 8 is mainly generated by the hydraulic pressure in the hydraulic chamber 23 . When the actuation reaction force acting on the input piston 18 becomes equal to the force acting on the input piston 18 from the push rod 19, the valve portion 26b of the valve member 26 comes into contact with the seat 50, and the hydraulic pressure in the hydraulic chamber 23 stops rising.

During the above operation, the valve member 31 is urged toward the spring 33 by the hydraulic pressure in the hydraulic chamber 23 because the outer diameter B of the small diameter portion 31 a is smaller than the diameter A of the seat 44 . The hydraulic pressure value Pmax of the hydraulic chamber 23 at which this biasing force becomes equal to the force F of the spring 33 is 4F/π (A ² - B ² ), and the hydraulic pressure of the hydraulic chamber 23 does not rise above Pmax. At times, the valve member 31 slides and separates its seat 44 from the valve portion 26a of the valve member 26, allowing the pressure oil in the passages 45 and 48 to escape to the drain chamber 35, thereby stopping the increase in oil pressure.
Therefore, even if the brake pedal 20 is depressed very strongly, the oil pressure in the hydraulic chamber 23 will not rise above Pmax. This Pmax is naturally lower than the maximum discharge oil pressure of the hydraulic pump P, and the supply of pressure oil from the hydraulic pump P to the power steering P/S is maintained. Pmax
Suppose that the discharge pressure of the hydraulic pump P increases to the maximum discharge pressure of the hydraulic pump P, then the discharge pressure of the hydraulic pump P becomes
The pressure oil is relieved from the relief valve attached to the power steering P/S, and pressure oil is no longer supplied to the power steering P/S.

In addition, the valve member 31 adjusts the hydraulic pressure in the hydraulic chamber 23 to Pmax.
When the valve member 31 slides relative to the input piston 18 in order to adjust the valve member 31, the presence of the damper chamber 32 suppresses the rapid sliding of the valve member 31, thereby suppressing the vibration of the valve member 31.

When the brake pedal 20 that has been depressed is released, the input piston 18 is pushed back by the hydraulic pressure in the hydraulic chamber 23 and the spring 43, and the valve member 31
The seat 44 is separated from the valve portion 26a. As a result, the hydraulic pressure in the hydraulic chamber 23 flows out to the reservoir connection port 42 through the hole 46, the axial hole 30, the passage 45, the drain chamber 35, the passage 36, the hole 38, the slit 39, the annular groove 40, and the hole 41. The oil pressure in chamber 23 decreases. As a result, the piston 37 and the power piston 16 are returned as shown in the figure by the spring 57 and the hydraulic pressure of the pressure chamber 54, and the pressure chamber 54 is moved to the valve mechanism 59.
The opening communicates with the hole 38.

In the embodiment described above, the valve member 26 is required because the oil discharged from the hydraulic pump is consumed only during operation. In order to obtain this, a valve portion corresponding to the valve portion 26a of the valve member 26 is fixed to the power piston, so that the valve member 26 is not necessary and it is sufficient to use the passage 12 as an inlet.

As mentioned above, in this invention, the control valve mechanism has a relief valve function, which does not increase cost or increase the size of the valve, and since a damper chamber is provided to suppress valve vibration, valve vibration does not occur. It is.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an embodiment of the present invention, and FIG. 2 is an enlarged view of the main parts. B: Hydraulic booster, P: Hydraulic pump, 1: Main body, 16: Power piston, 18: Input piston 24: Control valve mechanism, 23: Hydraulic chamber, 30: Stepped axial hole, 31: Stepped valve Member, 32: damper chamber, 33: spring.

Claims (1)

[Scope of utility model registration request] A main body, a power piston slidably provided within the main body, a hydraulic chamber provided within the main body for operating the power piston, and a hydraulic pressure in the hydraulic chamber that moves in the opposite direction to the power piston. A hydraulic booster comprising: an input piston having one end inserted into the main body so as to be pushed; and a control valve mechanism operated by the input piston to control hydraulic pressure applied from a hydraulic pump to the hydraulic chamber. A stepped axial hole is provided at one end of the input piston and has a smaller diameter at the back, and a hollow valve member that is a component of the control valve mechanism is fitted into this axial hole. The member has a small diameter portion liquid-tightly and slidably fitted into the small diameter portion of the axial hole, and a large diameter portion defining an annular damper chamber within the large diameter portion of the axial hole, and the input A spring that transmits the operating force applied to the piston to the valve member is installed in the small diameter portion of the axial hole, and oil in the hydraulic chamber is distributed between the small diameter portion of the axial hole, the inside of the valve member, and the small diameter portion of the axial hole. configured to flow into the drain chamber sequentially through the valve member and the gap between the other valve members,
In the hydraulic booster, a seat diameter between the two valve members is set larger than the small diameter portion of the valve member.