JP2692262B2 - Hydraulic booster - Google Patents

Description

The present invention relates to a hydraulic booster used in a brake booster or a clutch booster.

"Prior Art" A hydraulic booster generally has a power piston slidably provided in a housing, a power chamber formed at one end of the power piston in the housing, and a small diameter formed in the power piston. A stepped hole having a large-diameter hole opened to the power chamber, a supply passage communicating the small-diameter hole with a pressure fluid supply source, and a first hole provided in the small-diameter hole. 1 valve seat, a valve body slidably provided in the small diameter hole, seated on the first valve seat from the pressure fluid supply source side, and operated in conjunction with the input shaft, from the large diameter hole side An annular pin for contacting the valve body to separate the valve body from the first valve seat and introducing the pressure fluid from the pressure fluid supply source into the power chamber; A discharge passage that connects the chamber to the reservoir and a tip provided on the annular pin are provided. And a second valve seat that blocks communication between the power chamber and the discharge passage when the annular pin contacts the valve body.

Further, generally, the opposite end of the valve body seated on the first valve seat is passed through the second sealing means to face the balance chamber, and a pressure chamber is provided between the second sealing means and the first valve seat. The supply passage is communicated with the pressure chamber, and the balance chamber is communicated with the power chamber through the communication hole formed in the power piston.

In this type of hydraulic booster, when the brake pedal or the clutch pedal is released,
The annular pin is separated from the valve body to communicate the power chamber with the reservoir via the discharge passage, and the valve body is seated on the first valve seat to seal the pressure chamber to which the pressure fluid is supplied.

On the other hand, when the pedal is stepped on and the annular pin separates the valve body from the first valve seat, the second valve seat at the tip of the annular pin sits on the valve body, so that the power chamber and the reservoir are separated from each other. Since the communication fluid is cut off and the pressure fluid is supplied into the power chamber by the separation of the valve body from the first valve seat, the power piston can be advanced by the fluid pressure.

And at this time, since the fluid pressure introduced into the power chamber can be supplied to the balance chamber through the communication hole, the pressure receiving area on the power chamber side and the pressure receiving area on the balance chamber side of the valve body are made the same. With this, even if the pressure fluctuates, the acting force acting on the valve body can be balanced.

[Problems to be Solved by the Invention] In the conventional hydraulic booster, the first valve seat in the small diameter hole is formed by press-fitting a ring-shaped member into the small diameter hole. However, since the small diameter hole is located inside the large diameter hole, and it is necessary to reduce the axial dimension of the ring-shaped member in order to shorten the axial dimension of the hydraulic booster, It takes time and effort to press the ring-shaped member into the small diameter hole of the power piston, and there is a possibility that the pressure fluid may leak from the outer surface of the ring-shaped member and the inner surface of the small diameter hole.

Further, when forming a communication hole in the power piston that connects the balance chamber and the power chamber, a radial passage extending from the balance chamber to the radial outside of the power piston and an axial direction communicating with the radial passage. It is necessary to form the communication hole from the passage.

When the radial passage is formed by a drill, the radial passage needs to be bored from the outer peripheral surface of the power piston, so that the opening must be sealed with a plug member such as a ball. There is a risk that the plug member may come off as the structure becomes complicated.

On the other hand, a recess corresponding to the radial passage is formed on the base end surface of the push rod, the axial passage is opened at the tip portion of the power piston, and the opening of the axial passage is formed on the base end surface of the push rod. At the same time as the covering, the axial passage is made to communicate with the recess, but this also complicates the structure and is expensive.

"Means for Solving the Problem" In view of the above-mentioned circumstances, the present invention fits the small diameter portion and the large diameter portion of the stepped sleeve to the small diameter hole and the large diameter hole of the power piston, respectively, and also the fixing means. The large diameter portion of the stepped sleeve is connected and fixed to the pwer piston by the first step, and the valve body is seated on the tip of the small diameter portion of the stepped sleeve
The valve seat is formed, and the first sealing means is provided for maintaining liquid tightness between the small diameter portion and the small diameter hole.

Further, according to the present invention, a through hole penetrating into the small diameter hole is formed obliquely from an outer peripheral surface of the power piston, and the through hole is used as the supply passage, and a communication hole for communicating the balance chamber and the power chamber. Is formed on the extension line of the through hole.
It is composed of a communication hole and a second communication hole formed in the axial direction of the power piston, and further, the second sealing means is arranged between the through hole and the first communication hole to establish the first communication with the through hole. The communication with the hole is blocked.

[Operation] As in the former configuration, the stepped sleeve is fitted in the stepped hole of the power piston, and the large diameter portion of the stepped sleeve is connected and fixed to the power piston by a fixing means such as a lock nut or caulking. By doing so, since the large diameter portion is located outside the small diameter portion, the assembling work can be facilitated as compared with the conventional press-fitting work into the small diameter hole of the ring-shaped member. You can

A stepped sleeve is fitted in the stepped hole of the power piston to form a first valve seat at the tip of the small diameter portion of the stepped sleeve, and a gap between the small diameter portion and the small diameter hole is first sealed. Since it is sealed by means, leakage of the pressure fluid can be surely prevented.

On the other hand, in the latter configuration, since the first communication hole corresponding to the conventional radial passage is formed on the extension line of the through hole when the supply passage is formed, the first communication hole is formed in the opposite direction. Unlike the case of forming from the outer peripheral surface of the power piston, the first communication hole does not open to the outer peripheral surface of the power piston. Therefore, since a plug member for sealing the opening is not required, the structure is simple and there is no risk of the plug member falling off.

Embodiment The present invention will be described below with reference to an illustrated embodiment. A housing 1 of a hydraulic booster has a large-diameter hole 1a in a shaft portion thereof, and a right-hand side of a power piston 2 is provided in the large-diameter hole 1a. The large diameter portion 2a is slidably fitted. The left small diameter portion 2b of the power piston 2 is a through hole formed in the left end wall of the housing 1.
A seal member 3 holds liquid tightness in 1b and slidably penetrates through the seal member, and an output shaft 4 integrally formed at the tip end thereof is interlocked with a piston of a master cylinder (not shown).

The right end opening of the large-diameter hole 1a is sealed by a plug 11, and the plug 11 is fixed to the housing 1 by an annular nut 12. Plug 11 and power piston 2
Is a power chamber 13 into which pressure oil is introduced, and a spring 15 is housed in a low pressure chamber 14 formed on the opposite side of the power piston 2 from the power chamber 13. Normally, the power piston 2 is held in a non-actuated position where it abuts on the plug 11. And a low pressure chamber containing the spring 15
14 communicates with a reservoir 18 via a passage 16 and a conduit 17 formed in the housing 1.

A bottomed stepped hole is formed in the right end shaft portion of the power piston 2, and a large diameter hole 2 c of the stepped hole is opened in the power chamber 13. The small diameter portion 21a and the large diameter portion 21b of the stepped sleeve 21 are fitted into the small diameter hole 2d and the large diameter hole 2c of the power piston 2, respectively, and the large diameter hole on the right side of the large diameter portion 21b. 2c, a stopper ring 22 and a sleeve 23 are sequentially fitted, and a lock nut 24 is screwed into a female screw portion formed on the right end of the large-diameter hole 2c to fix the sleeve 23. Are fixed to the power piston 2 by punch caulking (not shown).

The tip of the small diameter portion 21a of the stepped sleeve 21 is a valve mechanism 27.
The valve body 29 is seated on the first valve seat 28 from the left side thereof by the resilience of a spring 30, and an O-ring or the like provided on the outer peripheral surface of the small-diameter portion 21a is provided. The outer peripheral surface of the small diameter portion 21a and the small diameter hole 2d are sealed by the sealing means 31.
When the valve body 29 is seated on the first valve seat 28, the communication between the power chamber 13 on the right side of the first valve seat 28 and the pressure chamber 32 on the left side is performed. Can be completely shut off.

As described above, in this embodiment, in order to provide the first valve seat 28 in the small diameter hole 2d, the stepped sleeve 21, the stopper ring 22, and the sleeve 23 are sequentially fitted into the stepped hole of the power piston 2, and Since the outermost sleeve 23 of the stepped hole of the power piston 2 is fixed by the lock nut 24 and the punch caulking, the ring-shaped member is press-fitted into the small-diameter hole 2d and this is inserted into the first valve seat 28. The assembly work can be made easier than in the case of

Further, since the gap between the small diameter portion 21a and the small diameter hole 2d of the stepped sleeve 21 is sealed by the sealing means 31, it is possible to reliably prevent the leakage of the pressure fluid as compared with the case where the ring-shaped member is press-fitted. it can.

Next, in the small-diameter hole 2d, a second sealing means 35 is provided on the left side of the first valve seat 28, and the pressure chamber is provided between the second sealing means 35 and the first valve seat 28. 32, a balance chamber 36 is formed on the left side of the second sealing means 35, and the balance chamber 36 is formed with a communication hole 37 and an annular groove 38 formed in the power piston 2 and a hole formed in the stepped sleeve 21. The power chamber 13 is communicated with the power chamber 13 via 39.

The left end portion of the valve body 29 is slidably penetrated by the second sealing means 35 while maintaining liquid tightness so as to reach the balance chamber 36, and the pressure receiving area of the valve body 29 on the balance chamber 36 side and the power By making the pressure receiving area on the chamber 13 side substantially the same, the valve element 29 is not moved forward and backward even if the pressure in the power chamber 13 and the pressure in the balance chamber 36 fluctuate.

The pressure chamber 32 has a supply passage 41 formed in the power piston 2 and an annular groove 42 formed in the outer peripheral surface of the power piston 2.
And a radial passage 43 formed in the housing 1 and a pump 45 through a conduit 44 connected to the passage 43. The pump 45 constantly supplies a predetermined pressure oil into the pressure chamber 32. We can supply them.

By the way, the supply passage 41 is configured as a through hole that penetrates obliquely from the outer peripheral surface of the power piston 2 into the small-diameter hole 2d, and a communication hole 37 that communicates the balance chamber 36 and the power chamber 13 with each other. It comprises a first communication hole 37 a formed on an extension of the supply passage 41 and a second communication hole 37 b formed in the axial direction of the power piston 2. The second sealing means 35 is disposed between the supply passage 41 and the first communication hole 37a to establish communication between the supply passage 41 and the first communication hole 37a, that is, the communication between the pressure chamber 32 and the balance chamber 36. Communication is cut off.

Thus, the first communication hole is provided on the extension of the supply passage 41.
When the first communication hole 37a is formed, unlike the case where the first communication hole 37a is formed from the outer peripheral surface of the power piston 2 in the opposite direction, the first communication hole 37a does not open to the outer peripheral surface of the power piston 2, Therefore, since a plug member for sealing the opening is not required, the configuration is simplified and there is no danger of the plug member falling off.

However, the aforementioned plug 11 has a large-diameter hole in the housing 1.
A through hole 11a is formed on the same axis as 1a, and an input shaft 49 linked to a brake pedal (not shown) is slidably fitted in the through hole 11a. And, at the tip of the input shaft 49, a flange portion 49a extending radially outward is formed,
An annular pin 50 constituting the valve mechanism 27 is attached to the shaft of the flange 49a.

The flange portion 49a of the input shaft 49 is
The stopper ring 22, which is located in the large diameter portion 21b and located on the right side of the large diameter portion 21b, prevents the power piston 2 from dropping rightward from inside the large diameter hole 2c of the power piston 2.

At this time, since the stopper ring 22 is positioned by being sandwiched between the stepped sleeve 21 and the sleeve 23, the stopper ring 22 is formed of a snap ring as in the conventional case, and the inner peripheral surface of the power piston 2 is formed. The stopper ring 22 can be reliably held at that position as compared with the case where the stopper ring 22 is positioned by being engaged with the annular groove formed in. However, it is also possible to integrally form the stepped sleeve 21 and the sleeve 23 and mount the stopper ring 22 in an annular groove formed on the inner peripheral surface of the sleeve 23.

Next, when the brake petal (not shown) is released, the input shaft 49 is urged to the right by a spring 51 mounted between the input shaft 49 and the stepped sleeve 21, and the flange The portion 49a is held in a non-actuated position in the drawing where it abuts on the tip surface of the plug 11.

In this state, the annular pin 50 is separated from the valve body 29, and a discharge passage 54 formed in the shaft portion of the annular pin 50 communicates with the power chamber 13 while providing a noise prevention provided inside the power chamber 13. An orifice 55, an axial passage 56 and a radial passage 57 formed in a shaft portion of the input shaft 49, an annular groove 58 formed in an inner peripheral surface in the through hole 11a of the plug 11, and a radius formed in the plug 11. Direction passage 59 and an axial passage 60 formed in the housing 1.
Then, the power chamber 13 is communicated with the reservoir 18 via the above-described passage 16, thereby communicating the power chamber 13 with the reservoir 18.

When the brake pedal is depressed, the input shaft
When the valve 49 is advanced, the valve body 29 is relatively seated on a second valve seat 64 formed at the distal end of the annular pin 50, and the discharge passage is formed.
54 and the power chamber 13
50 forcibly forces the valve body 29 against the spring 30 to force the first valve seat 28
Can be separated from.

Accordingly, the pressure oil introduced into the pressure chamber 32 is communicated with the power chamber 13 through a gap between the outer circumference of the annular pin 50 and the inner circumference of the sleeve 21, and the hydraulic pressure introduced into the power chamber 13 Thus, the brake can be operated by advancing the power piston 2 to the left at a predetermined boosting ratio in the same manner as a conventionally known hydraulic booster.

[Advantages of the Invention] As described above, in the present invention, the stepped sleeve having the first valve seat at the tip of the small diameter portion is fitted into the stepped hole of the power piston, and the outside of the stepped sleeve is fitted. Since the large diameter part of the is connected and fixed to the power piston with a fixing means such as a lock nut or caulking, the work is compared to the conventional assembling work in which the ring-shaped first valve seat member is press-fitted into the small diameter hole. The gap between the small-diameter portion of the stepped sleeve and the small-diameter hole of the power piston can be easily made
Since the sealing is performed by the sealing means, it is possible to reliably prevent the leakage of the pressure fluid.

Further, in the present invention, among the communication holes that communicate the balance chamber with the power chamber, a first radial passage corresponding to a conventional radial passage.
Since the communication hole is formed on the extension line of the supply passage for supplying the pressure fluid to the pressure chamber, the first communication hole is formed as in the case where the first communication hole is formed from the outer peripheral surface of the power piston in the opposite direction. Since the hole does not open on the outer peripheral surface of the power piston, and therefore a plug member for sealing the opening is not required, the structure is simplified and the plug member does not fall off.

[Brief description of the drawings]

 FIG. 1 is a sectional view showing one embodiment of the present invention. 1 ... Housing, 2 ... Power piston 2a ... Large diameter part, 2b ... Small diameter part 2c ... Large diameter hole, 2d ... Small diameter hole 13 ... Power chamber, 18 ... Reservoir 21 ... Step sleeve , 22 …… Stopper ring 23 …… Sleeve, 24 …… Lock nut 27 …… Valve mechanism, 28 …… First valve seat 29 …… Valve element, 31 …… Seal member 32 …… Pressure chamber, 35 …… No. 2 Sealing means 36 ... Balance chamber, 37 ... Communication hole 37a ... First communication hole, 37b ... Second communication hole 41 ... Supply passage, 45 ... Pump 49 ... Input shaft, 50 ... Annular pin 54: discharge passage, 64: second valve seat

Claims (2)

(57) [Claims] 1. A power piston slidably provided in a housing, a power chamber formed in one end of the power piston in the housing, and a small diameter hole and a large diameter hole formed in the power piston. A stepped hole having the large diameter hole opened to the power chamber, a supply passage communicating the inside of the small diameter hole with a pressure fluid supply source, and a first valve seat provided in the small diameter hole,
A valve body that is slidably provided in the small diameter hole and is seated on the first valve seat from the pressure fluid supply source side is operated in conjunction with the input shaft to contact the valve body from the large diameter hole side. An annular pin that comes into contact with the valve body to separate it from the first valve seat and introduces the pressure fluid from the pressure fluid supply source into the power chamber, and the shaft portion of the annular pin, which connects the power chamber to the reservoir. And a second valve seat that is provided at the tip of the annular pin and that blocks the communication between the power chamber and the exhaust passage when the annular pin contacts the valve body. In the force device, the small diameter portion and the large diameter portion of the stepped sleeve are respectively fitted in the small diameter hole and the large diameter hole of the power piston, and the large diameter portion of the stepped sleeve is connected to the power piston by a fixing means. Fix and seat the valve element on the tip of the small diameter part of the stepped sleeve. A hydraulic booster comprising: a first valve seat that forms a first valve seat, and a first sealing means that maintains liquid tightness between the small diameter portion and the small diameter hole. 2. A power piston slidably provided in the housing, a power chamber formed at one end of the power piston in the housing, and a small diameter hole and a large diameter hole formed in the power piston. A stepped hole having the large diameter hole opened to the power chamber, a supply passage communicating the inside of the small diameter hole with a pressure fluid supply source, and a first valve seat provided in the small diameter hole,
A valve body that is slidably provided in the small diameter hole and is seated on the first valve seat from the pressure fluid supply source side is operated in conjunction with the input shaft to contact the valve body from the large diameter hole side. An annular pin that comes into contact with the valve body to separate it from the first valve seat and introduces the pressure fluid from the pressure fluid supply source into the power chamber, and the shaft portion of the annular pin, which connects the power chamber to the reservoir. And a second valve seat that is provided at the tip of the annular pin and that blocks communication between the power chamber and the exhaust passage when the annular pin contacts the valve body. The opposite end of the valve body seated on the valve seat is passed through the second sealing means to face the balance chamber, and a pressure chamber is formed between the second sealing means and the first valve seat to form the pressure chamber. To connect the supply passage to
Further, in the hydraulic booster in which the balance chamber is communicated with the power chamber through the communication hole formed in the power piston, a through hole is formed obliquely from the outer peripheral surface of the power piston into the small diameter hole. The through hole as the supply passage, and a communication hole communicating the balance chamber with the power chamber is formed on the extension line of the through hole and a second communication hole is formed in the axial direction of the power piston. A hydraulic pressure characterized by comprising a communication hole, and further disposing the second sealing means between the through hole and the first communication hole to interrupt the communication between the through hole and the first communication hole. Booster.