JP2000198435A - Hydraulic pressure servo unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify a discharge passage, to improve the workability, to miniaturize a hydraulic pressure servo unit, and to reduce the weight of the device. SOLUTION: A discharge passage of a control valve 40 comprises an axial hole 33 and a radial hole 34 cut in a valve element 19, a radial hole 35 cut in a collar 46, a radial hole 36 cut in a power piston 12, a gap 55 between an outer circumferential surface of the power piston 12 and an inner circumferential surface of a hole 48 in a primary piston 43, an annular gap 56 between an inner circumferential surface of a second hole 6 in a housing 4 and an outer circumferential surface of the power piston 12, an annular gap 57 between an inner circumferential surface of the second hole 6 and an outer circumferential surface of the primary piston 43, a radial hole 58 cut in the housing 4 and a discharge outlet 59. The discharge passage is thus extended to the outer circumferential surface of the power piston 10 from the control valve 40, and further extended from the outer circumferential surface to a reservoir. Thereby, the discharge passage is simple in structure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of a hydraulic booster which boosts the operating force of an operating means to a predetermined magnitude by hydraulic pressure and outputs the boosted power.

[0002]

2. Description of the Related Art A hydraulic booster used for a brake hydraulic booster of an automobile or the like is designed to obtain a large output with a small input. As an example of the hydraulic booster, a hydraulic booster used in a brake system of an automobile is disclosed in Japanese Utility Model Application No. Hei 4-33402 (Japanese Utility Model Application Laid-Open No. Hei 5-84553).
No.) microfilm.

FIG. 4 is a view showing a hydraulic booster disclosed in this microfilm. In the drawing, 1 'is a hydraulic booster, 2' is a housing, 3 'is a plug, 4' is a power piston, 5 'is a control valve, 6' is a valve seat member, 7 'is a cylindrical fixing member, 8''Is a nut, 9' is a ball valve, 10 '
Is a valve member, 11 'is a cylindrical member, 12' is an input shaft, 13 'is a cylindrical stopper member, 14' is a reaction piston, 15 'is a power chamber, and 16' is an output shaft.

In the hydraulic booster 1 ', in the non-operating state shown in the drawing, the ball valve 9' of the control valve 5 'is seated on the valve seat member 6' and the tip of the cylindrical member 11 ' The valve part is separated from the ball valve 9 '. Therefore, the power chamber 15 'is cut off from the input port 17' always connected to the hydraulic pressure source (not shown), and communicates with the chamber 18 'which is always connected to the reservoir (not shown). ′, No hydraulic pressure is introduced, and the power piston 4 ′ does not operate.

When an input is applied from this inoperative state and the input shaft 12 'moves forward, the tubular member 11' also moves forward,
The tip valve portion of the cylindrical member 11 'is a ball valve 9' of the control valve 5 '.
And pushes the ball valve 9 ', so that the ball valve 9' is separated from the valve seat member 6 '. As a result, the power chamber 15 'communicates with the input port 17', and
8 ', the hydraulic fluid is introduced into the power chamber 15', and the power piston 4 'operates. By the operation of the power piston 4 ', the hydraulic booster 1' outputs from the output shaft 16 ',
The piston of a master cylinder (not shown) is operated, and the master cylinder generates brake fluid pressure. When the hydraulic pressure in the power chamber 15 'becomes large according to the input, the ball valve 9' is seated on the valve seat member 6 ', so that the output of the hydraulic booster 1' is
It becomes the size which boosted the input.

The hydraulic pressure in the power chamber 15 'pushes the reaction force piston 14' backward against the spring 19 ', but in the initial stage when the hydraulic pressure in the power chamber 15' is still small, the reaction force piston 14 ' ′ Does not contact the step 12′a of the input shaft 12 ′, so that the boosting ratio is large and the jumping action is performed. When the hydraulic pressure in the power chamber 15 'reaches a predetermined pressure, the reaction force piston 14' moves rearward (to the right in the figure) relative to the input shaft 12 ', and its rear end is the step of the input shaft 12'. After contact with the portion 12'a, the boosting ratio decreases and the jumping action ends, and the hydraulic booster 1 'returns to the normal boosting ratio.

When the input is lost, the input shaft 12 'is retracted by a return spring (not shown).
1 'also retreats, and the tip valve portion of the cylindrical member 11' is separated from the ball valve 9 'of the control valve 5'. As a result, the power chamber 15 'is shut off from the input port 17' and the chamber 18 '
The hydraulic pressure introduced into the power chamber 15 'is discharged to the reservoir, and the power piston 4'
Retreat by 0 '. When the cylindrical stopper member 13 'fixed to the input shaft 12' comes into contact with the stopper 25 'of the plug 3', the input shaft 12 'does not retreat any further, and is limited to the retreat, so that the inoperative state shown in FIG. Return. When the hydraulic pressure in the power chamber 15 'is completely discharged, the power piston 4' also returns to the inactive state shown in the figure, the hydraulic booster 1 'does not output, and the master cylinder is also inactive.

[0008]

In the above-mentioned conventional brake hydraulic booster 1 ', a discharge passage for discharging the pressurized fluid in the power chamber 15' to the reservoir is formed in a cylindrical shape from the control valve 5 '. After extending backward once through the member 11 'and the input shaft 12', it extends in the radial direction. Further, although the discharge passage is shown only up to the chamber 18 'in FIG.
Since the reservoir is arranged on the front side of the housing 4 ', the reservoir often extends forward from the chamber 18'. Therefore, not only is the structure of the brake hydraulic booster 1 'complicated, but also the workability of each hole of the discharge passage is poor.

[0009] Although a hole for a discharge passage is provided in the cylindrical member 11 ', the input shaft 12', the plug 3 'and the like,
Since the cylindrical member 11 'and the input shaft 12' require relatively high strength, not only the diameter must be increased to secure the strength of the cylindrical member 11 'and the input shaft 12', but also the plug 3 ′ Is provided with a hole for the discharge passage, so that the axial length of the plug 3 ′ must be increased. Therefore, the brake hydraulic booster 1 '
However, there is a problem in that the size becomes large and the weight also increases accordingly.

The present invention has been made in view of such circumstances, and has as its object to simplify a discharge passage, improve workability, and further reduce the size and weight of a hydraulic booster. It is to provide a device.

[0011]

In order to solve the above-mentioned problems, a first aspect of the present invention provides a reservoir for storing a hydraulic fluid,
A hydraulic pressure source for generating hydraulic pressure, a power chamber in which the hydraulic fluid is supplied from the hydraulic pressure source during operation and the non-operating hydraulic fluid is discharged to the reservoir through a discharge passage, and a hole in the housing. A power piston which is provided in a liquid-tight and slidable manner and operates by the power chamber pressure of the power chamber to generate an output, an input shaft to which an input is applied and which advances, and an operation controlled by the input shaft, When not operating, the power chamber is shut off from the hydraulic pressure source and communicates with the reservoir, and when operating, the power chamber is shut off from the reservoir and communicates with the hydraulic pressure source. A control valve for supplying to the power chamber in response to the input of the input shaft, wherein the control valve is actuated by the input shaft when the input shaft is moved forward and moves forward, and a valve body having a valve at a rear end; When the valve is not actuated, the valve is seated so as to be in front of the hydraulic pressure source. A first valve seat that communicates between the hydraulic pressure source and the power chamber by disconnecting the power chamber from the power chamber and separating the valve when the valve moves forward is separated from the power chamber when the valve is not operating. By seating, the power chamber and the reservoir communicate with each other via the discharge passage, and when the input shaft advances, the power chamber and the reservoir are shut off by sitting on the valve. A hydraulic booster having a second valve seat, wherein the discharge passage further includes a first passage provided in the valve body, and a diameter provided in the power piston so as to communicate with the first passage. And a third passage communicating with the second passage in the radial direction and comprising a gap between the outer peripheral surface of the power piston and the inner peripheral surface of the hole in the housing. Connecting a third passage formed by the gap and the reservoir. It is characterized in that it is at least composed of a fourth passage for.

Further, in the invention according to claim 2, the valve body is slidably supported by a collar fixed to a hole of the power piston, and the collar has a first passage of the valve body and the collar. A radial hole communicating with the second passage of the power piston is formed.

Further, according to the invention of claim 3, the power chamber is connected to an external hydraulic actuator, and the output of the power piston is transmitted via a transmission member provided at a front end of the power piston. It is characterized in that it is transmitted to a piston of an external actuator.

[0014]

In the hydraulic booster of the present invention having such a configuration, the discharge passage is provided in the first passage provided in the valve body of the control valve, the second passage in the radial direction provided with the power piston, and the power passage. A third passage formed by a gap between the outer peripheral surface of the piston and the inner peripheral surface of the hole of the housing, and a fourth passage provided in the housing. That is, the discharge passage extends from the valve body of the control valve to the outer peripheral surface of the power piston, and further extends from the outer peripheral surface of the power piston to the reservoir. Thereby, the discharge passage has a simple structure.

Further, since the structure of the discharge passage is simplified, machining of holes and the like is also simplified, and the workability of parts is improved, and no extra space for forming the discharge passage is required. The hydraulic booster is shortened, and the size and weight are reduced.

Further, since the collar for slidably supporting the valve body is formed with a radial hole communicating the first passage of the valve body and the second passage of the power piston, the collar has a radial hole. It becomes longer in the axial direction by the space provided. Therefore, the valve element is stably guided and supported by the collar, and smoothly advances during operation. In that case, even if the collar becomes long, it is only the space of the radial hole, so from the viewpoint of the entire hydraulic booster,
Will be shortened.

Further, in general, in the hydraulic booster, a transmission member for transmitting the output of the power piston to the piston of the external actuator is often provided at the front end of the power piston. Since the second passage provided in the power piston is provided in the radial direction and communicates with the outer peripheral surface of the power piston, the discharge passage can be easily and reliably provided.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of a brake hydraulic pressure generating apparatus employing an example of a hydraulic booster according to an embodiment of the present invention, FIG. 2 is a partially enlarged cross-sectional view of FIG.
FIG. 2 is a sectional view of a reaction force piston used in the brake hydraulic booster shown in FIG. 1.

As shown in FIGS. 1 to 3, the hydraulic booster 2 of this embodiment is configured as a brake hydraulic pressure generator 1 in combination with a master cylinder 3 corresponding to an actuator of the present invention. .

The hydraulic booster 2 has a housing 4. The housing 4 is formed continuously with a first hole 5 opening at the right end and a left end of the first hole 5. It has a stepped hole composed of the second hole 6 having a small diameter. 1st hole 5
Is closed by a plug 10 in a liquid-tight manner. The plug 10 is fixed to the housing 4 by being in contact with the steps of the first hole 5 and the second hole 6 by a nut 11 screwed to the housing 4. ing.

A power piston 12 of the hydraulic booster 2 is disposed in the second hole 6.
The rear side (the right side in FIGS. 1 and 2) has a large-diameter portion 12.
In FIG. 1A, the front side (the left side in FIGS. 1 and 2) is a small-diameter portion 12.
b, the large-diameter portion 12a
Are fitted in the second hole 6 in a liquid-tight and slidable manner by a seal member provided on the outer peripheral surface of the large diameter portion 12a.

The power piston 12 has a third hole 13 opening at the rear end of the power piston 12 and a third hole 1.
3 and a fourth hole 14 having a diameter smaller than the diameter of the third hole 13 which is formed continuously with the left end and closed at the left end, respectively, and these third and fourth holes 13 and 14 are formed. It is formed as one stepped hole. Power piston 1
2, a cylindrical valve seat member 15 is fixed in a liquid-tight manner with a part thereof located in the fourth hole 14, and the flange portion 15 a of the valve seat member 15 is provided in the third hole 13. The power piston 12 is fixed to the power piston 12 by a nut 17 screwed to the right end of the power piston 12 via the fitted cylindrical fixing member 16.

In the fourth hole 14, a valve body 19 having a conical valve 18 is slidably supported only by a collar 46, and the valve body 19 is provided with a conical valve 18 by a valve spring 20. It is constantly urged in the direction in which the valve seat member 15 is seated on the first valve seat 15c. An axial hole (corresponding to the first passage of the present invention) 33 and a radial hole (corresponding to the first passage of the present invention) 34 communicating with the axial hole 33 and penetrating in the radial direction are formed in the valve element 19. Has been established. Further, a radial hole 35 communicating with the radial hole 34 is formed in the collar 46. The radial hole 35 is located between a pair of front and rear O-rings for making the space between the outer peripheral surface of the collar 46 and the inner peripheral surface of the fourth hole 14 liquid-tight. Further, the power piston 12
The small diameter portion 12b has a radial hole communicating with the radial hole 35 and radially penetrating from the inner peripheral surface of the fourth hole 14 of the small diameter portion 12b to the outer peripheral surface of the small diameter portion 12b (the present invention). 36 (corresponding to two passages).

In the axial hole 15d of the valve seat member 15, there is provided a cylindrical member 21 having a second valve seat 21a at the tip which can contact the conical valve 18. This tubular member 21
Is fitted in an axial hole of a stopper member 23 screwed and fixed to the front end of the input shaft 22 and the valve seat member 1
It is fixed to the stopper member 23 by a spring 24 contracted between the cylinder member 5 and the cylindrical member 21. Input shaft 22
And the stopper member 23, the cylindrical projection 10 of the plug 10
a through the axial hole 10b. Further, the input shaft 22
Penetrates the plug 10 in a liquid-tight and slidable manner, and a rear end of the input shaft 22 is connected to a brake pedal (not shown). As shown in the figure, the flange-shaped stopper portion 23a of the stopper member 23 is
The cylindrical member 21, the input shaft 22, and the stopper member 23 come into contact with the tip 10c of the cylindrical projection 10a.
Each retraction limit is specified. Stopper member 2
A predetermined number of through-holes 23b are provided in the third stopper portion 23a for a flow path of the pressure liquid supplied to the power chamber 31.

A cylindrical reaction force piston 25 is slidable between the outer circumference of the input shaft 22 and the stopper member 23 and the inner circumference of the axial hole 10b of the cylindrical projection 10a of the plug 10. Mated. As shown in FIG. 3, a left end of the reaction force piston 25 in FIG.
5a and a second flange portion 25b are provided.
The stopper portion 23a of the stopper member 23 can contact the left side portion of the flange portion 25a. When the stopper portion 23a contacts, the stopper member 23 retreats further with respect to the reaction force piston 25. The stopper portion 25c is a stopper portion 25c for preventing the movement.

The right side of the second flange 25b is
When the reaction force piston 25 moves backward by a predetermined amount with respect to the power piston 12, the engagement portion 25d is engaged with the step 16a of the cylindrical fixing member 16. Further, the right end 25 e of the reaction force piston 25 can contact the step 22 a of the input shaft 22. The spring 2 is located between the second flange portion 25 b of the reaction force piston 25 and the cylindrical fixing member 16.
The second flange portion 25b of the reaction force piston 25 is normally operated by the spring force of the spring 26.
Is in contact with the rear surface of the flange portion 15a of the valve seat member 15.

Further, the housing 4 has an input port 27 which is always connected to a hydraulic pressure source comprising a hydraulic pump and an accumulator, and into which the hydraulic pressure of the hydraulic pressure source is introduced.
A passage hole 28 is provided for communicating with the second hole 6, and the passage hole 28 is formed on the outer periphery of the power piston 12.
The power piston 12 is further provided with a passage hole 30 communicating between the annular groove 29 and the valve seat member 15 of the fourth hole 14 from the valve seat 19 side. The input port 27, the passage hole 28, the annular groove 29, and the passage hole 30 constitute a hydraulic pressure supply passage.

A power chamber 31 is formed in the second hole 6 between the plug 10 and the rear end of the power piston 12.
The power chamber 31 is always in communication with the axial hole 15d of the valve seat member 15. The stopper member 2 is provided in the power chamber 31.
The third stopper portion 23a and the first and second flange portions 25a and 25b of the reaction force piston 25 are located respectively. An axial groove (not shown) is provided in a sliding portion of the spring supporting portion of the cylindrical fixing member 16 with respect to the cylindrical projecting portion 10a of the plug 10, and an axis of this sliding portion of the cylindrical fixing member 16 is provided. The working fluid can flow freely on both sides in the direction. The power chamber 31 is always communicated with an output port (not shown) through a passage hole 32 formed in the housing 4, and the output port is connected to a wheel cylinder (not shown) in one of the two brake systems. (Corresponding to the hydraulic actuator of the present invention).

Further, the small diameter portion 12b of the power piston 12
The radial hole 36 of the power piston 12 has a gap 5 between the outer peripheral surface of the small diameter portion 12b of the power piston 12 loosely fitted in the hole 48 of the primary piston 43 and the inner peripheral surface of the hole 48, as described later.
5, an annular gap 56 (corresponding to a third passage of the present invention) between the inner peripheral surface of the second hole 6 of the housing 4 and the outer peripheral surface of the small-diameter portion 12b of the power piston 12, and the inner periphery of the second hole 6 An annular gap 57 between the surface and the outer peripheral surface of the primary piston 43, a radial hole 58 formed in the housing 4 and a discharge port 59 communicate with a reservoir for a hydraulic booster (not shown). That is, the axial hole 33, the radial holes 34, 35, 3
6, the gap 55, the gap 56, the gap 57, the radial hole 58 (corresponding to the fourth passage of the present invention) and the discharge port 59,
A discharge passage for discharging the first hydraulic fluid to the hydraulic booster reservoir is formed.

Further, although not shown, a hydraulic circuit connecting the input port 27 and the reservoir for the hydraulic booster is provided with a hydraulic pump and the hydraulic pump in the same manner as a conventional general hydraulic brake system. An accumulator is provided on the discharge side via a check valve. The accumulator always stores a predetermined pressure by the discharge pressure of the hydraulic pump, and the accumulated pressure of the accumulator is stored in the input port 2.
7 is always introduced.

When the brake pedal is not operated and the brake pedal is not depressed, the conical valve 18 and the first
The valve seat 15c and the second valve seat 21a of the tubular member 21 have a positional relationship shown in FIGS. That is, the conical valve 18 is seated on the first valve seat 15c of the valve seat member 15 and is separated from the second valve seat 21a of the tubular member 21. In this state, the conical valve 18 always communicates with the input port 27. The passage hole 30 and the axial hole 15d of the valve seat member 15 are shut off, and the axial hole 15d of the valve seat member 15 and the discharge port 5 are closed.
9 is in communication with the axial hole 33 of the valve body 19 which is always in communication. Therefore, when the brake is not operated, the power room 3
1 is shut off from the hydraulic pump and the accumulator, and communicates with the reservoir for the hydraulic booster.
No pressure fluid is supplied to 1.

When the brake pedal is depressed, the input shaft 22 moves forward, the second valve seat 21a of the tubular member 21 comes into contact with the conical valve 18, and the conical valve 18 moves to the second valve seat 2.
1a, the conical valve 18 is separated from the first valve seat 15c of the valve seat member 15, so that in this state, the axial hole 15d of the valve seat member 15 and the axial hole 33 of the valve body 19 are shut off. At the same time, the passage hole 30 communicates with the axial hole 15d of the valve seat member 15. Therefore, at the time of the brake operation, the power chamber 31 is disconnected from the reservoir for the hydraulic booster and communicates with the hydraulic pump and the accumulator,
The pressure fluid of the accumulator passes through the gap between the conical valve 18 and the first valve seat 15c, the gap between the flange portion 15a and the stopper portion 23a, and the through hole 23b of the stopper portion 23a. It is supplied to the rear end side. Thus, the conical valve 18, the first valve seat 15 c of the valve seat member 15 and the second valve seat 21 a of the tubular member 21 allow the power chamber 31 to be connected to the hydraulic pump or accumulator by a hydraulic pressure source or a hydraulic booster. The control valve 40 of the hydraulic booster 2 that selectively switches and controls one of the reservoirs is provided. Further, the power chamber 31 is always in communication with a chamber 42 facing the left end of the valve element 19 via an axial passage hole 41 formed in the power piston 12.

The small diameter portion 12b of the power piston 12 is loosely fitted in a hole 48 opened at the right end of the primary piston 43, and an adjusting member (corresponding to a transmission member of the present invention) 49 is provided at the tip of the small diameter portion 12a. Is provided.
The power piston 12 operates the primary piston 43 of the master cylinder 3 via the adjusting member 49 at the time of operation. The rear end of the primary piston 43 is provided in the second hole 6 of the housing 4 for the hydraulic booster.
Are slidably fitted by a cup seal 45 in a liquid-tight manner. Reference numerals 38 and 39 denote simple holes for always setting the annular space 37 in which the step portion 22a of the input shaft 22 is located to atmospheric pressure. It is designed to move smoothly.

Next, the operation of the thus-configured hydraulic booster 2 of this embodiment will be described. When the brake pedal is not operated and the brake pedal is not depressed, the input shaft 22 does not advance, and the control valve 40 operates as described above with reference to FIGS.
In the inoperative state shown in FIG. Therefore, the pressurized liquid from the accumulator is not supplied to the power chamber 31, so that the power piston 12 does not operate and the hydraulic booster 2 does not output. The right end 25e of the reaction force piston 25 is connected to the input shaft 2
2 and the stopper 23a of the stopper member 23 is connected to the tip 1 of the cylindrical projection 10a.
0c and the first flange portion 25 of the reaction force piston 25
a of the stopper portion 25c.
The position is forward from c.

When the brake operation is performed by depressing the brake pedal, the input shaft 22, the stopper member 23 and the cylindrical member 21 advance, and the conical valve 18 is seated on the second valve seat 21a and the first The control valve 40 is switched away from the valve seat 15c. At this time, since the valve element 19 is guided only by the collar 46, the valve element 19 moves smoothly when pressed by the tubular member 21. When the control valve 40 is switched, the power chamber 31 is disconnected from the reservoir for the hydraulic booster and communicates with the accumulator, so that the pressurized liquid from the accumulator is introduced into the power chamber 31. The pressurized liquid introduced into the power chamber 31 causes the sliding resistance of the power piston 12 and the master cylinder 3
When the pressure reaches the pressure that overcomes the spring force of the primary return spring 54, the power piston 12 moves forward by this pressurized liquid, and the hydraulic booster 2 outputs. With the output of the hydraulic booster 2, the primary piston 43 of the master cylinder 3 is used.
Operates to generate a master cylinder pressure in the primary chamber 52. Further, the secondary piston 44 moves forward by the master cylinder pressure of the primary chamber 52 and moves to the secondary chamber 53.
Generates the master cylinder pressure.

The power chamber pressure in the power chamber 31 is
2, the master cylinder pressure in the secondary chamber 53 of the master cylinder 3 is supplied from the secondary output port 67 to the wheel cylinder of the other system. At this time, the power room pressure,
The master cylinder pressure in the primary chamber 52 and the master cylinder pressure in the secondary chamber 53 are equal to each other.

Further, the pressure fluid in the power chamber 31 is also introduced into the chamber 42 through the axial passage hole 41, and the fluid pressure in the chamber 42 causes the valve body 19 to oppose the input of the input shaft 22. It is urged to.

The reaction force piston 2 is driven by the hydraulic pressure in the power chamber 31.
5 is the power piston 1 against the spring force of the spring 26
2 and the input shaft 22 are displaced to the right.
In the early stage of operation when each wheel cylinder has a loss stroke and each of these wheel cylinders does not substantially generate a braking force, it does not reach the point where the rear end 25e of the reaction force piston 25 comes into contact with the step 22a of the input shaft 22. Absent. Thus, the right end 25 e of the reaction force piston 25 is
The input shaft 22 does not receive any force from the reaction force piston 25 because it does not contact the stepped portion 22a. Therefore, the input shaft 22 is connected to the power chamber 3 which receives the relatively small effective pressure receiving surface of the stopper member 23 and the cylindrical member 21 at the tip thereof.
The force due to the hydraulic pressure in 1 is applied, and this force is transmitted to the driver as a reaction force.

When the reaction force of the input shaft 22 becomes equal to the input of the input shaft 22, the conical valve 18 is seated on both the first valve seat 15c and the second valve seat 21a, and the power chamber 31 becomes the accumulator and the hydraulic pressure multiplier. It is shut off from any of the force device reservoirs. When the input of the input shaft 22 further increases, the conical valve 18 is again separated from the first valve seat 15c, and the hydraulic fluid in the accumulator is further supplied to the power chamber 31, and the hydraulic pressure in the power chamber 31 further increases. I do. Thereafter, the conical valve 18 is moved to the first valve seat 1
By repeatedly seating and unseating on 5c, the hydraulic pressure in the power chamber 31 continuously increases at a predetermined boost ratio as the input of the input shaft 22 increases.

During the loss stroke of each wheel cylinder, the right end 25e of the reaction force piston 25 is not in contact with the step 22a of the input shaft 22, so that the input shaft 22 on which the hydraulic pressure in the power chamber 31 acts is effective. The pressure receiving area is small, and the boost ratio at this time is large. For this reason, the output of the hydraulic booster 2 rises very greatly with respect to the input of the input shaft 22 at a large boost ratio, and the hydraulic booster 2 performs a so-called jumping action.

When the fluid pressure in the power chamber 31 further rises and the power piston 12 further advances, and the loss stroke of each wheel cylinder is eliminated, each wheel cylinder generates a braking force, and substantially, two brake systems are used. The brakes are activated. In this state, the raised power chamber 31
The right end 25e of the reaction force piston 25 abuts on the step 22a of the input shaft 22 due to the hydraulic pressure in the input shaft 22, and the reaction force piston 25 applies a force to the input shaft 22 by the urging force due to the hydraulic pressure in the power chamber 31.
It acts to oppose the input of 2. Therefore, the reaction force acting on the input shaft 22 increases, and the hydraulic booster 2
Output of the input shaft 22 rises smaller than the input of the input shaft 22 during the loss stroke, and the jumping action ends.

Thereafter, the hydraulic booster 2 boosts the input of the input shaft 22 at a normal relatively small boosting ratio because the reaction force increases, and the hydraulic pressure in the power chamber 31 decreases. The hydraulic pressure corresponds to this boost ratio.

When the brake pedal is released by releasing the brake pedal, the input shaft 22, the stopper member 23 and the cylindrical member 21 are all retreated to the right, and the control valve 4 is released as described above.
In the case of 0, the second valve seat 21a is switched away from the conical valve 18. The power chamber 31 is provided with the axial hole 15 of the valve seat member 15.
d, the hydraulic fluid in the power chamber 31 communicates with the reservoir for the hydraulic booster through the gap between the conical valve 18 and the second valve seat 21a and the discharge passage described above, and the hydraulic fluid in the power chamber 31 is used for the hydraulic booster. Drained into reservoir. At this time, the stopper portion 2 of the stopper member 23
Since the input shaft 22 retreats greatly until 3a comes into contact with the stopper portion 25c of the reaction force piston 25, the second valve seat 2
1a is greatly separated from the conical valve 18, and the control valve 40 opens greatly. Therefore, the pressure fluid in the power chamber 31 is quickly discharged through the discharge passage, the fluid pressure in the power chamber 31 decreases, and the power piston 12
By the primary return spring 54.

By discharging the hydraulic fluid in the power chamber 31, the hydraulic fluid in one of the wheel cylinders is also quickly discharged to the hydraulic booster reservoir through the power chamber 31. At this time,
The pressure fluid of the other wheel cylinder is also discharged to the master cylinder reservoir through the master cylinder 3. As a result, the brakes of both brake systems are quickly released.

When the hydraulic pressure in the power chamber 31 decreases to a predetermined pressure, the reaction force piston 25 advances relatively to the power piston 12 and the input shaft 22 by the spring force of the spring 26 and the flange of the valve seat member 15 The right end 25e of the reaction force piston 25 is separated from the step portion 22a of the input shaft 33 while being in contact with the portion 15a.

Input shaft 2 until brake release is almost completed
2 further retracts, the stopper portion 2 of the stopper member 23
The contact of the input shaft 22, the stopper member 23, and the tubular member 21 with the input shaft 22, the stopper member 23, and the tubular member 21 is stopped by the contact of the 3a with the distal end 10c of the tubular protrusion 10a of the plug 10. Both will be receded. However, even if the retraction of the input shaft 22, the stopper member 23, and the tubular member 21 is stopped, the power piston 12, the reaction force piston 25, the conical valve 18, and the valve seat member 15 all continue to retreat. For this reason, the stopper portion 23 a of the stopper member 23 is
c, and the conical valve 18 approaches the second valve seat 21a of the tubular member 21.

When the rear end of the power piston 12 comes into contact with the plug 10 shown in FIGS.
Is stopped, the power piston 12 is in the inoperative position, and the master cylinder 3 is also inoperative accordingly, and the brake is quickly and completely released. In this state, the conical valve 18 comes very close to the second valve seat 21a, the gap between the conical valve 18 and the second valve seat 21a becomes extremely small, and the seat is about to be seated. Therefore, when the brake pedal is depressed next and the input shaft 22 and the cylindrical member 21 advance, the second valve seat 21a immediately contacts the conical valve 18, and the conical valve 18 is seated on the second valve seat 21a. The user immediately separates from the first valve seat 15c. That is, the loss stroke for performing the switching operation of the control valve 40 becomes extremely small, and the brake operates quickly.

As described above, the brake is quickly operated when the brake is operated, and the brake is quickly released when the brake is released, so that the brake fluid pressure generating device 1 becomes extremely responsive.

When the hydraulic pressure source such as the pump and the accumulator fails and the hydraulic fluid of the accumulator does not flow into the power chamber 31 during the brake operation, when the brake pedal is further depressed and the input piston 8 moves further forward, Similarly, the cylindrical member 21 contacts the conical valve 18, and the conical valve 18
The valve body 19 is pressed forward via the. Then, the stopper member 23 moves forward, and its front end contacts the valve seat member 15. Therefore, the input shaft 22 directly pushes the primary piston 43 via the stopper member 23, the valve seat member 15, the power piston 12, and the adjustment member 49,
The primary piston 43 moves forward to generate a master cylinder pressure in the primary chamber 52. Further, the secondary piston 44 is moved by the master cylinder pressure in the primary chamber 52.
Moves forward to generate a master cylinder pressure in the secondary chamber 53. These master cylinder pressures are supplied to the two wheel cylinders via the primary output port 66 and the secondary output port 67, respectively, to operate the brake. In this way, even when the pump is out of order, the two systems of the brake operation are reliably performed.

As described above, according to the hydraulic booster 2 of this embodiment, the valve element 19 is guided only by the collar 46, so that the guide is provided at two places of the collar and the power piston as in the prior art. Thus, the valve element 19 can be moved more smoothly than in the case of performing the operation.

Since the pressure liquid discharge passage uses a gap between the inner peripheral surface of the second hole 6 of the housing 4, the outer peripheral surface of the power piston 12, and the outer peripheral surface of the primary piston 43, the pressure fluid discharge passage is formed. Even if the adjusting member 49 is provided in front of the power piston 12 as in the example, the discharge passage can be easily provided.

In the hydraulic booster 2 of the above-described example, the hydraulic booster 2 is applied to a semi-full power brake system so that the power chamber pressure is supplied to one of the wheel cylinders. However, according to the present invention, as disclosed in the above-mentioned publication, the power chamber pressure is not supplied to one of the wheel cylinders and the power piston 12
The present invention can also be applied to a hydraulic booster used only for the operation of the hydraulic booster.

Further, in the hydraulic booster 2 of the above-described example, the jumping characteristic is provided by the reaction force piston 25, but the reaction force piston 25 is not always necessary and can be omitted.

Further, instead of the conical valve, another valve such as a ball valve can be used as the control valve 40. Further, the hydraulic booster of the present invention can be applied to other hydraulic systems other than the brake system.

[0055]

As is apparent from the above description, according to the hydraulic booster of the present invention, the discharge passage extends directly from the control valve to the outer peripheral surface of the power piston, and the discharge passage extends from the outer peripheral surface of the power piston to the reservoir. , The structure of the discharge passage can be simplified, and the discharge passage can be simplified. Further, since the structure of the discharge passage is simplified, the workability of the parts can be improved, and the hydraulic booster can be shortened, reduced in size and reduced in weight.

Further, since the collar for slidably supporting the valve body is elongated in the axial direction by the space provided with the radial hole for communicating the first passage of the valve body and the second passage of the power piston. Thus, the valve can be stably guided by the collar. Thereby, the valve body can be advanced smoothly. In that case, even if the color becomes longer,
The hydraulic booster can be shortened as a whole.

Further, even when the transmission member is provided at the front end of the power piston, the second
Since the passage is provided in the radial direction so as to communicate with the outer peripheral surface of the power piston, the discharge passage can be easily and reliably provided.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a brake hydraulic pressure generator to which an example of an embodiment of a hydraulic booster according to the present invention is applied.

FIG. 2 is a partially enlarged sectional view of the brake hydraulic booster shown in FIG.

FIG. 3 is a detailed sectional view of the reaction force piston shown in FIGS. 1 and 2;

FIG. 4 is a sectional view of a conventional hydraulic booster.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Brake hydraulic pressure generator, 2 ... Hydraulic booster, 3 ... Master cylinder, 12 ... Power piston, 15 ... Valve seat member, 15a ... Flange part, 15b ... Radial groove, 15
c: first valve seat, 16: cylindrical fixing member, 18: conical valve, 1
9: valve element, 21: tubular member, 21a: second valve seat, 22:
Input shaft, 22a step, 23 stopper member, 23a
Stopper portion, 23b: through hole, 23c: radial groove,
25: reaction force piston, 27: input port, 31: power chamber, 3
3 ... axial hole, 34 ... radial hole, 35 ... radial hole, 36
... radial holes, 59 ... outlets, 40 ... control valves, 55, 56,
57: gap, 58: radial hole, 59: outlet

Continued on the front page (72) Inventor Hiroyuki Yamaga 2-11-6, Shinmeicho, Higashimatsuyama-shi, Saitama F-term in the Matsuyama Plant of Automotive Equipment Co., Ltd. 3D048 BB51 BB59 BB60 CC10 GG17 GG27 GG29 HH15 HH16

Claims (3)

[Claims] 1. A reservoir for storing hydraulic fluid, a hydraulic pressure source for generating hydraulic pressure, a hydraulic fluid supplied from the hydraulic pressure source during operation, and a non-operating hydraulic fluid being supplied to the reservoir via a discharge passage. And a power piston, which is provided in a hole in the housing in a liquid-tight and slidable manner and operates by the power chamber pressure of the power chamber to generate an output. An input shaft, the operation of which is controlled by the input shaft, disconnects the power chamber from the hydraulic pressure source when not operating and communicates with the reservoir, shuts off the power chamber from the reservoir when activated, and connects to the hydraulic pressure source. A control valve for communicating the hydraulic fluid from the hydraulic pressure source to the power chamber in response to the input of the input shaft, wherein the control valve is actuated by the input shaft when the input shaft advances. Forward, valve body with valve at rear end and front when not in operation When the valve is seated, the fluid pressure source and the power chamber are shut off, and when the valve is advanced, the valve is unseated so that the fluid pressure source and the power chamber are communicated with each other. When the first valve seat and the non-operating valve are separated from each other, the power chamber communicates with the reservoir through the discharge passage, and is seated on the valve when the input shaft advances. A hydraulic booster having a second valve seat that shuts off between the power chamber and the reservoir, wherein the discharge passage further includes a first passage provided in the valve body, and a first passage provided in the valve body. A second radial passage provided in the power piston so as to communicate therewith, and a second radial passage provided between the outer peripheral surface of the power piston and the inner peripheral surface of the hole of the housing; A third passage formed of a gap, the third passage provided in the housing, Third consisting of
A hydraulic booster comprising at least a fourth passage for communicating the passage with the reservoir. 2. The valve body is slidably supported by a collar fixed to a hole of the power piston. The collar has a first passage of the valve body and a second passage of the power piston. 2. A hydraulic booster according to claim 1, wherein a radial hole is formed to communicate with the hydraulic booster. 3. The power chamber is connected to an external hydraulic actuator, and an output of the power piston is transmitted to a piston of the external actuator via a transmission member provided at a front end of the power piston. 3. The hydraulic booster according to claim 1, wherein the hydraulic booster is transmitted.