JPH10167090A - Hydraulic booster - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate trouble with a cup seal in a power steering device even if a second valve for communicating and shutting off an outlet is provided in addition to a first valve for communicating and shutting off an inlet. SOLUTION: A valve that switches an outlet 120 and a reservoir tank 70 from a mutually shut-off state to a mutually communicated state is provided as a third valve which operates in response to the stop of the supply of hydraulic fluid from a main pump to an inlet 110, so that even when no hydraulic fluid is supplied by the main pump, a power steering device can be replenished with the hydraulic fluid. Also, a means 20 located on the side of the inlet 110 and including a piston which makes a stroke when the hydraulic fluid flows in is adopted as a switch means which, when detecting the failure of a first hydraulic fluid supply system including the main pump, operates a second hydraulic fluid supply system including an emergency pump 90.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a booster for a brake device in a vehicle or the like, and in addition to a first hydraulic fluid supply system including a main pump shared with a power steering device, a first hydraulic fluid supply system. A second system including an emergency pump and a switching valve for responding to a failure of the hydraulic fluid supply system
The present invention relates to a hydraulic booster provided with a hydraulic fluid supply system.

[0002]

BACKGROUND OF THE INVENTION As one of hydraulic boosters for operating a master cylinder, a throttle valve inside the device is throttled in response to an input from a driver, and a hydraulic pressure corresponding to the throttle amount of the throttle valve is set. There is known a type in which pressure is generated and a boosting action is obtained by using the hydraulic pressure. This type of booster has the advantage that it is not necessary to provide an accumulator or the like for storing the boosted hydraulic pressure in a system including the servo hydraulic pressure due to the throttle action of the throttle valve.
Moreover, in a system including this type of booster, the hydraulic fluid supplied by the pump flows into the closed system so as to return to the pump after flowing into the booster. Therefore,
In a system including such a type of booster, a hydraulic fluid supply circuit for circulating hydraulic fluid by a pump is often used for a power steering device mounted on a vehicle. That is, the pump is often used for both the booster and the power steering device. For the above, see, for example, Japanese Utility Model Laid-Open No. 58-35457 or JP-A-57-938.

In such a type of booster, when the first hydraulic fluid supply system including the main pump fails,
There is known a concept of adding a fail-safe function of operating a second hydraulic fluid supply system including an electric emergency pump (for example, see Japanese Patent Publication No. 3-2700). The failure of the first hydraulic fluid supply system may be caused by various causes such as failure of the pump body, breakage of a supply pipe from the main pump to the booster, and failure of a drive source of the pump.

When the fail function is added, in order to make the second hydraulic fluid supply system function effectively,
At least a shutoff valve (first valve) for switching the inflow side from the communicating state to the shutoff state in response to the supply of the working fluid from the main pump to the inflow port being lost. In this regard, in the conventional booster disclosed in Japanese Patent Publication No. Hei 3-2700, the flow of the liquid from the inflow port toward the servo chamber is allowed, but the flow in the opposite direction is prevented. A check valve to be operated, the check valve to function as a first valve, and a flow switch (switch means) for detecting the failure is arranged on the side of the outlet for sending out the hydraulic fluid. I have.

The inventors of the present invention have considered integrating the first valve and the switch means and arranging them both on the side of the inflow port. By using a piston that includes a piston that strokes in accordance with the above, the invention that performs both switching and valve switching by using the stroke of the piston was completed, and was previously proposed as Japanese Patent Application No. 8-299502. . By the way, the booster function of the booster
When giving priority to the function of the booster among the two functions of the operation of the power steering device, in addition to the first valve that shuts the inflow port, the outflow side is shut off from the communication state. Preferably, a second valve for switching to the state is provided.

[0006]

However, if such a second valve is provided, when the first hydraulic fluid supply system breaks down and the hydraulic pump is not supplied with the hydraulic fluid by the main pump, the outlet of the booster is placed in the second position. As a result, the supply path of the hydraulic fluid to the inlet of the power steering device is closed. As a result, when the steering is operated in a state where there is no supply of the hydraulic fluid from the main pump, the power steering device moves to a state where the piston inside moves to suck the hydraulic fluid from the inlet into the cylinder chamber. However, the supply of the hydraulic fluid cannot be sufficiently received, and a negative pressure is generated inside. The negative pressure acts on the cup seal that separates the entrance side passage of the power steering device from the outside, and disturbs the mounting posture of the cup seal,
It has been found that in some cases, a sealing failure may be caused. Therefore, an object of the present invention is to solve a problem associated with a cup seal in a power steering device even when the second valve is provided. Another object of the present invention is to provide a technique capable of smoothly supplying hydraulic fluid to a power steering device even when a first hydraulic fluid supply system including a main pump fails. .

[0007]

The present invention is applied to a system including a power steering device 50 downstream of a booster 10, as shown in FIG. The booster 10 includes an inlet 110
In the system including the power steering device 50 including the drain port 130 in addition to the power steering device 5 and the power outlet device 120,
It communicates with the reservoir tank 70 through 0. Usually the first
Since the main pump 30 of the hydraulic fluid supply system is driven by the engine of the vehicle, the booster 1 for brake operation is used.
It is located at a position distant from 0. The reservoir tank 70 is arranged integrally with or close to the main pump 30. Therefore, the drain port 130 of the booster 10 must be connected to the reservoir tank 70 through the pipe. On the other hand, the emergency pump 90 of the second hydraulic fluid supply system is an electric relatively small pump,
Can be integrally attached to the housing.

According to the present invention, in addition to the first and second switching valves described above, the valve which operates in response to the supply of the hydraulic fluid from the main pump 30 to the inflow port 110 is further provided. A third valve is provided for switching between the side of the reservoir 120 and the side of the reservoir tank 70 from the shut-off state to the communicating state. Thus, the working fluid can be effectively supplied to the power steering device 50 even when the working fluid is not supplied by the main pump 30. Further, it detects that the first hydraulic fluid supply system including the main pump 30 is out of order, and operates the second hydraulic fluid supply system including the electric emergency pump 90 based on the detection. As the switch means, as in the prior application, a means including a piston located on the side of the inflow port 110 and stroked by a liquid flow or a hydraulic pressure according to the inflow of the working fluid is applied. It is preferable to configure the first, second and third valves. Further, an auxiliary reservoir tank having a smaller capacity than the reservoir tank 70 is provided in the middle of a drain communication passage inside the housing of the booster 10, which connects the drain port 130 and the drain port opening / closing valve, and the auxiliary reservoir tank is passed through the auxiliary reservoir tank. It is preferable that the outflow port 120 and the reservoir tank 70 communicate with each other. Then, instead of the reservoir tank 70, the auxiliary reservoir tank becomes the second liquid storage part, and the hydraulic fluid can be smoothly supplied to the power steering device.

[0009]

The preferred embodiment is a hydraulic booster used in the system shown in FIG. FIG. 2 is a side sectional view showing a section along the axial direction of the hydraulic booster 10 according to the embodiment.
3 is a cutaway view of a part of the booster 10 in FIG. 2, a top view as viewed from above, FIG. 4 is a cross-sectional view along line 4-4 in FIG. 3, and FIG. The details of the arranged switch means are shown. The housing 210 of the booster 10 has an inlet 1 through which hydraulic fluid from the pump 30 flows in addition to the cylinder hole 212 extending in the axial direction.
10, an outlet 120 for sending the hydraulic fluid to the power steering device 50, and a drain port 130 connected to the reservoir tank 70. As FIG. 4 reveals, the drain port 130 is at one end of the nipple joint 23,
Further, the inflow port 110 and the outflow port 120 are screw holes for pipe connection.

The cylinder hole 212 of the housing 210
The servo piston 400 penetrates through the housing 210 and fits in the hole 212 so as to be movable. Mounting flange 2 on the axial direction of cylinder hole 212
The side with 10f is an input side that receives an input from the pedal in response to the driver's pedal operation, and has a slightly larger diameter hole 212.
The opposite side with m is the output side where the master cylinder is located. The output side opens to insert the master cylinder,
On the input side, a lid member 214 covers the opening of the cylinder hole 212, and a plunger 216 as an input member penetrates the center of the lid member 214 in the axial direction. Plunger 216 receives a pedaling force from a pedal through push rod 217. A lid member 214 screwed to the opening of the cylinder hole 212 and integrated with the housing 210
Holds the seal rings 215i and 215o inside and outside,
The opening is sealed. In addition, the outer peripheral side seal ring 2
15o is an outward flange 214 of the lid member 214 itself.
f prevents the inner ring from coming off.
The retainer ring 218 prevents the detachment. The retainer ring 218 fits into the inner end surface of the lid member 214, and the fitted state is changed to the housing 210.
Is maintained by the inward flange 211f.

The servo piston 4 in the cylinder hole 212
Reference numeral 00 denotes a cross-sectional shape suitable for the inner diameter of the cylinder hole 212, which extends from the input side to the output side in the cylinder hole 212, and has a length that is approximately half the length of the cylinder hole 212. At the center of the servo piston 400, there is a center hole 410 extending in the axial direction, and at the output end, there is a ring-shaped relatively deep groove 420. Center hole 410
Is closed on the output side where the groove 420 is located, whereas the side facing the input side is open. Such a central hole 4
10, a return spring 430 is inserted into the back of the closed hole, and then a spool 600 and a flange portion 216f of the plunger 216 are sequentially inserted. The return spring 430 pushes one end of the spool 600 to the input side, and abuts the other end of the spool 600 on the end face of the flange portion 216f of the plunger 216. Opening 410b into which flange 216f enters
Has a larger diameter than the other part of the center hole 410, and the step 410 s behind the large-diameter opening 410 b regulates the relative amount of movement between the servo piston 400 and the plunger 216. In the example of FIG. 2, the snap ring 432 that fits into the groove on the inner peripheral wall surface of the large-diameter opening portion 410 b hits the flange portion 216 f of the plunger 216 and the plunger 21.
6 are defined. In addition, servo piston 4
The return spring 450 for the servo piston 400 is inserted into the groove 420 provided in
This is a groove to be supported by The spring receiver 452 is provided in the groove 4
The part inside 20 becomes the actual spring support,
The portion located outside the groove 420 has a rod-shaped output member 4.
60 is supported. In the return state shown in FIG. 2, that is, in the non-operation state, the servo piston 400 receives the urging force of the return spring 450 and moves its input end (particularly, the ring-shaped protrusion 402 on the outer periphery of the end). Housing 210
On the inward flange 211f.

At the outer periphery of the servo piston 400, seal rings 470a and 470b are provided at both ends in the axial direction, respectively.
In the cylinder hole 212, a servo chamber 480 is defined on the side where the lid member 214 is located, and an air chamber 490 is defined on the side where the output member 460 is located. The inflow port 11 is provided between the seal rings 470a and 470b.
0, outlet 120 and drain port 130 and spool 60
There is each passage communicating with a central hole 410 where a 0 is located.
Each passage includes an inflow passage 1100 communicating between the inflow port 110 and the center hole 410, an outflow passage 1200 communicating between the outflow port 120 and the center hole 410, and a drain port 13.
Drain communication passage 13 communicating between zero and center hole 410
00. As FIG. 4 shows more clearly, each of those passages includes a groove on the outer periphery of the servo piston 400 and a radial hole passage extending radially.

The spool 600 in the center hole 410 cooperates with the servo piston 400 to connect or disconnect the drain port 130 and the servo chamber 480 with the drain port on-off valve and the inlet port 110. Servo room 480
And a throttle valve that sets the communication between the inflow port 110 and the outflow port 120 to a throttled state and a non-throttled state. The main part of the drain opening / closing valve is the first land 610. The first land 610 is connected to a radial passage 6 provided in the spool 600.
It is located in the part adjacent to 40. In the non-operation initial state shown in FIG. 2, the first land 610 forms a gap passage 615 between the first land 610 and the inner peripheral side of the servo piston 400. In this case, the servo chamber 480 is provided between the internal passage 2160 provided in the plunger 216 and the central passage 6 of the spool 600.
000 and the radial passage 640 through the gap passage 615 to the drain communication passage 1300. However, when the booster 10 operates, when the spool 600 moves forward, the gap passage 615 is shut off, and the drain communication passage 130 is closed.
The state between the 0 side and the servo chamber 480 is cut off.

In addition, the supply valve is provided with a drain port opening / closing valve.
It is located opposite the radial passage 640. The main body of the supply valve is a second land 620, and the second land 620 has a tapered shape with a small gradient of, for example, about 1.5 °. The supply valve having such a second land 620 is in a shut-off state in a non-operating initial state shown in FIG. 2 in which the gap passage with the inner peripheral side of the servo piston 400 is substantially zero. However, when the booster 10 is operated, the supply valve enlarges the gap passage around the tapered second land 620 and becomes in a communicating state. Thereby, the inlet 1
The hydraulic fluid flowing in from the spool 10 is supplied to the spool 6 through the supply valve.
The fluid flows into the servo chamber 480 through the radial passage 640 and the center passage 6000 of the second cylinder, and further through the internal passage 2160 of the plunger 216.

On the other hand, the third land 6 which is the main body of the throttle valve
30 is located forward (that is, closer to the output side) than both the first and second lands 610 and 620. The third land 630 forms a gap passage 635 between the third land 630 and the inner peripheral side of the servo piston 400 in the inactive initial state shown in FIG. 2, similarly to the first land 610 of the drain opening / closing valve. I have. The gap passage 635 has a sufficient flow passage cross-sectional area, and is in a non-restricted state from the inlet 110 to the outlet 120. However, the third land 630 is slightly smaller than the outer diameter of the first land 610. Therefore, the third land 630 forms a clearance passage between the third land 630 and the inner peripheral side of the spool 600 even when the booster 10 is operated. Since the gap passage during operation has a small flow passage cross-sectional area, that portion acts as a throttle. The throttle increases the hydraulic pressure of the hydraulic fluid supplied to the servo chamber 480 without hindering the circulation of the hydraulic fluid through the power steering device 50, and causes the booster 10 to effectively exhibit the boosting function.

Further, in the booster 10, the portion of the drain communication passage 1300 inside the servo piston 400 is branched, and the second communication passage 2 which bypasses the drain opening / closing valve is provided.
300 are provided. Second communication passage 230
Numeral 0 originates in the middle of the drain communication passage 1300, extends parallel to the axis of the servo piston 400, opens at the rear end of the servo piston 400, and communicates with the servo chamber 480. Then, the second communication passage 23 facing the servo chamber 480
A check valve 800 for replenishing the liquid is arranged in the opening of 00. In the example shown in FIG. 2, the check valve 800 includes a ball-shaped valve body 810 and the valve body 8
The valve spring 830 includes a valve spring 830 that urges the valve spring 10 toward the valve seat 820 and a retainer 840 that supports one end of the valve spring 830. The cross section of the retainer 840 is U-shaped, and the second
Is press-fitted into the opening of the communication passage 2300 and is integrated with the servo piston 400.

Next, attention is paid to the vicinity of the inlet 10 of the hydraulic booster 10. Inflow passage 1100 following inflow port 10
Is mainly a hole passage provided in the housing 210 itself. As part of such a hole passage, there is a hole 1110 orthogonal to the axis of the inlet 110. The hole 1110 is a blind hole whose opening is a screw hole. The hole 1110 detects that the switch means 20, that is, the first hydraulic fluid supply system including the main pump 30, is malfunctioning, and based on the detection, detects the second hydraulic fluid supply system including the emergency pump 90. A hole for receiving a switch that activates the system.
Here, in addition to the original switching function, the switch means 20 switches both the inflow port 110 and the outflow port 120 to a cutoff state or a communication state.
And the function of a second valve, and the function of a third valve for switching the state between the outflow port 120 side and the reservoir tank 70 side from the shut-off state to the communicating state. Therefore, the hole 1110 is connected to the drain port 130 side in addition to the inflow port 110 and the outflow port 120.

The switch means 20 includes a piston 24 located in the hole 1110, a terminal portion 25 located at the opening of the hole 1110, and a piston 24 located in the hole 1110.
Spring 2 for urging the spring toward the opening from the back of the hole 1110
6 is provided. The terminal portion 25 is supported by the nut member 25n screwed to the opening, the U-shaped holding member 25h fitted in the nut member 25n, and the holding member 25h. 252, and a boot 25b attached to the outer periphery of the nut member 25n and sealing between the nut member 25n and the housing 210 and waterproofing around the internal contact member 25c. Also, the piston 24 has a hole 1110
From the side of the opening of the first contact 251 toward the back of the hole,
The first small diameter portion 2411 and the first small diameter portion 2
At the end adjacent to 411, a first middle diameter portion 2421 constituting a first seal portion 241s for the first valve;
A second small diameter portion 2412 forming a flow passage from the side of the inlet 110 to the outlet 120 in the hole 1110, and a second portion for the second valve at an end adjacent to the second small diameter portion 2412. The second middle diameter portion 2422 constituting the seal portion 242 s of the third valve portion, further, a third seal portion 243 s for the third valve and the second middle diameter portion 2422 in the middle of the second middle diameter portion 2422. And a reduced diameter portion 2423 having a slightly reduced diameter. The piston 24 is, so to speak, a spool, and each seal portion 241s, 242s, 243
The part constituting s corresponds to the land. Here, the first seal portion 241s is provided at the inlet 110 to which the hydraulic fluid is supplied by the first hydraulic fluid supply system including the main pump 30.
Side and the side of the center hole 410 inside the servo piston 400 function as a first switching valve for switching to a state of communication. The second seal portion 242s is connected to the side communicating with the inlet 110 through the central hole 410 inside the servo piston 400 and the power steering device 5.
It functions as a second switching valve that shuts off the side of the outlet 120 that communicates with 0 and switches to a state of communication. The first switching valve is a valve for enabling the supply of the working fluid by the second working fluid supply system including the emergency pump 90 when the first working fluid supply system is out of order. On the other hand, the second switching valve is a valve for shutting off the flow of the hydraulic fluid to the power steering device 50 when the first hydraulic fluid supply system is out of order.

Here, the switch means is enlarged, and FIG. 5A shows a state in which hydraulic fluid is not supplied from the main pump 30, and FIG. 5 shows a state in which hydraulic fluid is supplied from the main pump 30. See B in FIG. In B of the figure,
The first and second valves are in communication with each other, and arrows p,
As shown by q, the central hole 4 inside the servo piston 400
10 communicates with the main pump 30 and the power steering device 50, respectively. However, since the third valve is in a shut-off state and the flow passage on the outer periphery of the reduced diameter portion 2423 is closed, the side of the auxiliary reservoir tank 700 and the side of the power steering device 50 are shut off from each other. On the other hand, in FIG. 7A, since the first and second valves are in the shut-off state, while the third valve is in the communicating state, the flow passage on the outer periphery of the reduced diameter portion 2423 is opened, and the arrow r
As described above, the auxiliary reservoir tank 700 communicates with the power steering device 50 side. Therefore, in FIG. 7A, the hydraulic fluid in the reservoir tank 70 can be effectively replenished to the power steering device 50 through the auxiliary reservoir tank 700, and the generation of the negative pressure as described above can be prevented. it can.

Now, the reservoir tank 70 is provided with the booster 1
0 and a capacity enough to store the hydraulic fluid required for operation of both the power steering device 50, for example, 1000
Although it has a relatively large capacity of about cc, if the piping is broken, the working fluid in it will be lost to the outside.
In such a case, even if the emergency pump 90 is driven, the emergency pump 90 can supply the necessary hydraulic fluid even if the emergency pump 90 is driven only if the normal piping connection through the pipeline is taken. Can not. In that regard, in the booster 10, by providing the auxiliary reservoir tank 700 inside the housing 210, the hydraulic fluid having the capacity required for the second hydraulic fluid supply system including the emergency pump 90 is always contained therein. We are trying to secure. The capacity of the auxiliary reservoir tank 700 is, for example, 100 to 150
cc, which is smaller than that of the reservoir tank 70. As can be seen from FIGS. 3 and 4, the auxiliary reservoir tank 700 is provided with a hole 7 provided in the housing 210.
10 and the opening of the hole 710 is closed tightly by a lid member 720 screwed to the housing 210. The auxiliary reservoir tank 700 also has a merit of smoothing the supply of the working fluid to the power steering device 50 as a second tank. In addition, the auxiliary reservoir tank 700, as shown in FIG.
The connection hole 7610 communicates with the center hole 410 inside the servo piston 400, and another connection hole 790 communicates with the suction side of the emergency pump 90.

Further, the discharge side of the emergency pump 90 is connected to a check valve 2 as shown in FIGS.
8 communicates with the center hole 410 through a horn-shaped recess and an oblique passage 190. Further, the oblique passage 190 itself passes through a radial through hole of the servo piston 400,
It communicates with the main pump 30 side. As can be seen from FIG. 2, the horn-shaped concave portions following the check valve 28 on the discharge side from the emergency pump 90 are offset from each other.

[Brief description of the drawings]

FIG. 1 is a connection diagram showing an example of a system including a hydraulic booster of the present invention.

FIG. 2 is a side sectional view showing one embodiment of the hydraulic booster of the present invention.

FIG. 3 is a top view of the embodiment of FIG. 2;

FIG. 4 is a sectional view taken along line 4-4 in FIG. 3;

FIG. 5 is an enlarged detail view showing a switch means.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Hydraulic booster 110 Inflow port 120 Outflow port 130 Drain port 20 Switch means 210 Housing 30 Main pump 400 Servo piston 480 Servo room 50 Power steering device 600 Spool (valve member) 70 Reservoir tank 700 Auxiliary reservoir tank 90 Emergency Si pump

Continued on the front page (72) Inventor Kazunori Yamawaki 5-2931, Urago-cho, Yokosuka City, Kanagawa Prefecture Inside Nabco Yokosuka Factory

Claims (5)

[Claims] 1. A throttle valve inside an apparatus is throttled in response to an input from a driver, a hydraulic pressure is generated in accordance with the throttle amount of the throttle valve, and a boosting action is obtained using the hydraulic pressure. And a hydraulic booster that shares the main pump with the power steering device. The hydraulic booster includes: a) a cylinder hole extending in the axial direction, and a hydraulic pump for flowing hydraulic fluid from the main pump into the cylinder hole. A housing including an inflow port, an outflow port for sending out the hydraulic fluid inside the cylinder hole to the power steering device, and a drain port connected to an external reservoir tank; b fits movably into the cylinder hole in the housing; A servo piston defining a servo chamber in a cylinder bore; c supported by the servo piston, in cooperation with the servo piston, between the drain port and the servo chamber; A drain port opening / closing valve for making a communication state or a cutoff state, a supply valve for making a cutoff state or a communication state between the inflow port and the servo chamber, and the throttle valve between the inflow port and the outflow port A second hydraulic fluid supply system including an emergency pump that assists the first hydraulic fluid supply system when the first hydraulic fluid supply system including the main pump fails. A hydraulic booster comprising the following three switching valves that are activated in response to the supply of hydraulic fluid from the main pump to the inflow port being stopped. Booster. A first valve for switching the side of the inflow port from a communication state to a cutoff state; A second valve for switching from a communication state to a cutoff state between the outflow port side and the inside of the cylinder hole; A third valve for switching from a shut-off state to a communicating state between the outlet side and the reservoir tank side; 2. A switch means for detecting that the first hydraulic fluid supply system is out of order and for activating the second hydraulic fluid supply system based on the detection. 2. The hydraulic type according to claim 1, further comprising a piston located at a position, and a piston that strokes by a liquid flow or a hydraulic pressure according to an inflow of the hydraulic fluid, and wherein the first, second, and third valves are formed around the piston. Booster. 3. The switch means is located in a hole in the interior of the housing proximate to the inlet and the piston is movable in the hole, and the switch means includes a piston and a piston. A valve spring for closing both the first and second valves around the piston and for urging the third valve to be in communication with the piston, and a contact for switching operation according to a stroke of the piston The hydraulic booster according to claim 2, comprising: 4. A hole inside the housing includes a plurality of large-diameter portions and a plurality of medium-diameter portions, and the middle-diameter portion has a plurality of seal portions for sealing in cooperation with the piston. The hydraulic booster according to claim 3, wherein a seal portion functions as each of the first, second, and third valves. 5. An auxiliary reservoir tank having a capacity smaller than that of the reservoir tank is provided in the middle of a drain communication passage inside the housing for connecting the drain port and the drain port opening / closing valve. The hydraulic booster of claim 1, wherein said hydraulic booster communicates with said reservoir tank through a reservoir tank.