JPS6144064A - Hydraulic booster - Google Patents

Abstract

PURPOSE:To make the closability of an inlet valve at the time of its closing as well as to reduce the initial motional resistance of a valve body in time of its opening, by making up the inlet valve of a hydraulic booster into umbrella-type form, while installing the specified diametral shaft part projectingly on the same axis at both ends of it. CONSTITUTION:A hydraulic booster B connectedly installed in a master cylinder M houses a booster piston 19 inside a booster cylinder 16. And, both first and second valve chests 331 and 332 are partitioned off with a partition wall 32 held between. Next, an inlet valve Vi and an outlet valve Vo are set up in each of these valve chests 331 and 332. In this case, the inlet valve Vi is constituted of the valve chest 331, an edge-form valve seat 37 formed in a boundary part with a valve hole 36 to be opened to the rear end wall, a umbrella-type valve body 38 touching or separating to or from the valve seat 37 and a valve closing spring 39. And, the valve body 38 is made up of installing a first shaft part 38a to be fitted in a guide cylinder 40 fitly attached to the booster piston 19 and a second shaft part 38b passing through the valve hole 36 and projecting in the valve chest 332 in front and in the rear.

Description

Detailed Description of the Invention A0 Object of the Invention (1) Industrial Application Field The present invention relates to a booster cylinder; and a rear output hydraulic chamber having a larger pressure-receiving area; an input rod connected to the booster piston so as to be able to move forward and backward;
an inlet valve provided in the oil passage connecting the input and output hydraulic chambers and linked to the input rod so as to close when the input rod retreats and open when the input rod moves forward; and an inlet valve that connects the output hydraulic chamber and the oil tank. A valve is provided in the oil passage connecting the input rod, and opens when the input rod retreats.
The present invention relates to a booster comprising: an outlet valve interlocked with the input rod so as to be closed during forward movement.

(2) Conventional technology Conventionally, this type of booster includes one that uses a spool valve as the valve body of the inlet valve, and one that uses a ball valve. Since the closing force of the inlet valve is not generated, the initial resistance of the valve body when opening the inlet valve is small, and the input rod can be operated easily.
On the other hand, since the occluding property when the valve is closed is poor, the hydraulic pressure in the input hydraulic chamber tends to leak to the output hydraulic chamber side. Since the hydraulic pressure acts on the valve body as a valve-closing force, there is a drawback that the initial movement resistance of the valve body increases by the valve-closing force.

(3) Problems to be Solved by the Invention The present invention has been proposed in view of the above points, and has good occluding properties when the inlet valve is closed, and a valve body for opening the artificial valve. It is an object of the present invention to provide a booster having a small initial resistance.

B1 Structure of the Invention (1) Means for Solving Problems According to the present invention, the inlet valve is formed in the booster piston and communicates with the input hydraulic pressure chamber, and opens into the valve chamber and outputs the output hydraulic pressure. a valve seat formed at the boundary between a valve hole communicating with the chamber; an umbrella-shaped valve body accommodated in the valve chamber to open and close the valve hole in cooperation with the valve seat; a valve-closing spring that biases in a closing direction, and a first shaft portion that is oil-tightly and slidably supported at one end of the valve body by a guide cylinder that constitutes a front end wall of the valve chamber; Further, a second shaft portion interlocked with the input rod is provided at the other end, and the cross-sectional area of the first shaft portion is
A feature is that the cross-sectional area of the valve body is set to be equal to or slightly smaller than the cross-sectional area at the point where the valve body is seated on the valve seat.

(2) Effect When the inlet valve is closed, the hydraulic pressure introduced from the hydraulic source into the input hydraulic chamber is also introduced into the valve chamber and acts on the valve body of the inlet valve.
With the above configuration, the valve closing force of the valve body due to the oil pressure is suppressed to zero or extremely small, and the valve closing force of the valve body is controlled by the set load of the valve closing spring. Therefore, the initial resistance of the input rod that opens the large mouth valve is extremely small.

Moreover, the umbrella-shaped valve body has extremely good obstructing properties when seated on the valve seat.

(3) Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings. M indicates a tandem type mask cylinder for a two-system hydraulic brake of an automobile, and an oil tank 2 is formed on the upper side of the cylinder body 1. Inside, the lower half is separated by a partition wall 2α and a front oil reservoir 2. and a rear oil sump 22.

The cylinder hole 3 of the cylinder body 1 has a small diameter hole 3α passing directly below the oil tank 2, and a large diameter hole 3b connected to the rear end of the small diameter hole 3α.
It is formed in a stepped manner. The small diameter hole 3α has a front oil reservoir 2I.
The front hydraulic chamber (not shown), which is supplied with oil, is connected to the cylinder hole 3.
The entire front mask piston 4 is defined between the front end wall of the front mask piston 4 and the rear mask piston 5 is defined between the front mask piston 4 and the rear hydraulic chamber 6 that is supplied with oil from the rear oil reservoir 22.
The front end portion of the rear mask piston 5, that is, the small diameter piston portion 5a, is slidably engaged with the large diameter hole 3b, and the rear end portion of the rear mask piston 5, that is, the large diameter piston portion 5b is slidably engaged with the large diameter hole 3b. Therefore, the rear mask piston 5 is composed of a small diameter piston portion 5α and a large diameter piston 5z having a larger diameter than the small diameter piston portion 5α.

A replenishment oil chamber 7 is defined in the large diameter hole 3b by both piston portions 5α and 575, and this oil chamber 7 is communicated with the rear oil sump 22 via an oil passage 8.

An elastic piston cup 9 is provided on the front surface of the small diameter piston portion 5α.
is installed, and an IJ port 10 is bored in the cylinder body 1 and opens just before the piston cup 9 at the retraction limit of the rear mask piston 5 to communicate between the rear hydraulic chamber 6 and the oil passage 8. In the small diameter piston part 5α,
A through hole 11 is bored through which the supply oil chamber 7 communicates with the back of the piston cup 9.

The front hydraulic chamber (not shown) and the rear hydraulic chamber 6 accommodate return springs 12 that bias the front and rear mask pistons 4 and 5 in the backward direction, respectively.

When the rear mask piston 5 is pushed forward and the piston cup 9 crosses the opening of the relief boat 1o, hydraulic pressure is generated in the rear hydraulic chamber 6;
A brake hydraulic circuit (not shown) is connected to the brake hydraulic circuit (not shown).

When the rear mask piston 5 retreats from the forward position and the rear hydraulic chamber 6 is depressurized, the outer periphery of the piston cup 9 bends forward due to the pressure difference between the front and rear, creating a gap between it and the inner surface of the cylinder hole 3. As a result, the oil in the rear oil sump 22 flows into the oil path 8,
It flows into the rear hydraulic chamber 6 through the supply oil chamber 7 and the through hole 11,
Hydraulic oil is replenished, and if excessive replenishment occurs, the excess is returned to the rear oil sump 22 from the relief boat 10.

The front mask piston 4 moves forward as the pressure in the rear hydraulic chamber 6 increases, generates hydraulic pressure in the front hydraulic chamber, and supplies this to the corresponding brake hydraulic circuit. Also, when reversing, the front oil sump 21
The oil pressure generation mechanism and the oil replenishment mechanism are substantially the same as those for the rear hydraulic chamber 6 side, so a detailed explanation thereof will be omitted.

An annular body 1 is attached to the rear end of the cylinder body 1 of the mask cylinder M.
A booster cylinder 16 of a hydraulic booster B is connected with the cylinder 5 in between, and the cylinder body 1 and the booster cylinder 16 are connected by bolts 17.

Here, the small diameter hole 3a of the cylinder hole 3 of the mask cylinder M
DI is the diameter of the large diameter hole 3h, D2 is the diameter of the large diameter hole 3h, and the annular body 15 is
inner diameter 8, cylinder hole 18 of booster cylinder 16
Assuming that the diameter of is D4, these dimensions are set in the following relationship.

D, <D3<D4<D2 The booster piston 19 has a front small diameter piston portion 19α,
Rear large diameter piston part i9b and large diameter piston part 19b
The small diameter piston part 19a and the large diameter piston part 19h are composed of a rod part 19c protruding from the rear end surface, and the small diameter piston part 19a and the large diameter piston part 19h are connected to the inner hole of the annular body 15 and the cylinder hole 18 of the booster cylinder 16.
The rod portion 19c penetrates the rear end wall of the booster cylinder 16 in an oil-tight manner and projects to the outside.

In order to define the retraction limit of this booster piston 19,
Annular stepped portion 1 capable of supporting the rear end surface of the large diameter piston portion 19b
8a is formed at the rear end of the cylinder hole 18.

Facing -C1 The annular body 15 supports the rear end of the rear mask piston 5 on its front end surface and defines its retraction limit. Further, in the cylinder hole 18, the annular body 15 and the large diameter piston portion 19b define an input hydraulic chamber 20 therebetween, and the large diameter piston portion 19b and the rear end wall of the booster cylinder 16 define an output hydraulic chamber 21 therebetween. to be accomplished. The output hydraulic chamber 21 is naturally formed to have a larger pressure receiving area than the input hydraulic chamber 20. Also, the rear master piston 5 of the mask cylinder M
The large piston portion 5h of the booster piston 19 and the small diameter piston portion 19fZ of the booster piston 19 define an outlet chamber 22 therebetween.

The input hydraulic pressure chamber 20 is connected to the oil tank 2 by a supply oil passage 23, and a hydraulic pump 24 as a hydraulic pressure source for pumping the reservoir of the oil tank 2 to the input hydraulic chamber 20 is interposed in the oil passage 23. A pressure accumulator 25 is connected downstream of the pump 24 .

The outlet chamber 22 includes a radial groove 28 provided on the front end surface of the annular body 15 and an annular oil passage 2 formed on the rear end of the cylinder body 1.
9 and a return oil passage 30 connected to the oil passage 29 .

The booster piston 19 has a first valve chamber 331 and a second valve chamber 332 adjacent to each other with a partition wall 32 in between.
First valve chamber 33. to the input hydraulic chamber 20 via the oil passage 34,
The second valve chambers 332 are communicated with the output hydraulic chambers 21 via oil passages 35, respectively. The partition wall 32 has a valve hole 3 passing through its axis.
6 is drilled.

First valve chamber 33. has an inlet valve Vi, and a second valve chamber 33□
are each provided with an outlet valve Vo.

The large mouth valve Vi has the first valve chamber 33. an edge-shaped valve seat 37 formed at the boundary between the valve hole 36 and the valve hole 36 opening in the rear end wall; an umbrella-shaped valve body 38 that cooperates with the valve seat 37 to open and close the valve hole 36; It is composed of a valve closing spring 39 that urges the valve body 38 in the closing direction.

The valve body 38 is connected to the first valve chamber 33. A first shaft portion 38α that slidably and oil-tightly penetrates the guide tube 40 fitted to the booster piston 19 to constitute the front end wall of the booster piston 19, and a second shaft portion that passes freely and slidably through the valve hole 36 and has a second shaft portion 38α that slidably passes through the guide tube 40 fitted to the booster piston 19. It has a second shaft portion 38b projecting into the valve chamber 332 at the front and rear, and an annular groove 43 communicating with an oil passage 42 connected to the output hydraulic pressure chamber 21 is formed in the second shaft portion 38b.

Further, an oil passage 44 that communicates between the second valve chamber 332 and the outlet chamber 22 is bored in the valve body 38 .

The outlet valve Vo has a conical valve seat 45 formed at the tip of the second shaft portion 38b, and cooperates with the valve seat 45 to open the oil passage 44.
It is composed of an umbrella-shaped valve body 46 that opens and closes the valve body, and a valve opening spring 47 that biases the valve body 46 in the opening direction. The above valve body 4
6 has a shaft portion 46α that oil-tightly and slidably penetrates the guide tube 48 fitted to the booster piston 19 to constitute the rear end wall of the second valve chamber 332, and the tip of the shaft portion 46α A valve opening spring 47 that biases the valve body 46 in the opening direction is connected to the valve opening spring 47 .

In the above, the cross-sectional area of the first shaft portion 38a of the valve body 38 is S
l, the cross-sectional area of the valve body 38 at the seating point on the valve seat 37 is S2,
Assuming that the cross-sectional area of the shaft portion 45a of the valve body 46 is S3, these dimensions are selected so that the following relationship holds.

S, =S, , WakashikuhaS, <52 and S2-5I character.

・・・・・・・・・ (1) S,=S3. Young 1. <It-15, (,53 and 53-
5,4°... (2) The guide tube 48 has a cylinder portion 48α whose rear end extends close to the rear end of the rod portion 19C of the booster piston 19,
A guide piston 49 that abuts the shaft portion 46a is slid onto the cylinder portion 48 (Z), and a stop ring 5° that defines the retraction limit of the guide piston 49 is fixed to the rod portion 19c of the booster piston 19.

An input rod 51 operated by a brake pedal P is connected to the guide piston 43 .

The booster piston 19 has a large diameter hole 53 that opens on its front surface, and a small diameter hole 54 that opens on the rear end wall of this large diameter hole 53.
A rubber elastic piston 55 and a pressure receiving piston 56 of the same diameter are formed in the large diameter hole 53 in order from the back thereof.
are slid together, and the first shaft portion 3 of the valve body 38 is still in the small diameter hole 54.
8α and a reaction piston 57 whose both ends can come into contact with the opposing surfaces of the elastic piston 55 are slidably connected.

An output rod 58 is integrally protruded from the front surface of the pressure receiving piston 56, and this output rod 58 deeply enters a recess 59 on the rear surface of the rear mask piston 5 and comes into contact with the piston 5, whereby the rear piston 5 and the booster piston 19 are arranged as close as possible.

The depth of the recess 59 is selected to be equal to or larger than the radius of the large diameter piston portion 5b of the rear mask piston 5. In this way, when the rear mask piston 5 is pushed by the output rod 58, an alignment action can be given to the piston 5.

In the above, the pressure receiving piston 56, the elastic piston 55, and the reaction piston 57 constitute the reaction mechanism R that transmits the operational reaction force of the mask cylinder M to the input rod 51.

Next, the operation of this embodiment will be explained.

When the brake pedal P is not actuated, the guide piston 49 is at the backward limit supported by the stop ring 5o, as shown in the figure.
The valve body 38 of the inlet valve Vi is held in a closed state by the force of a valve closing spring 39, and the valve body 46 of the outlet valve Vo is held in an open state by the force of a valve opening spring 47. Therefore, the person, output hydraulic chamber 20.
21 is shut off, while the output hydraulic chamber 21 is connected to the oil passage 35.
, second valve chamber 332, oil passage 44, outlet chamber 22, radial groove 2
8. Since it communicates with the oil tank 2 through the annular oil passage 29 and the return oil passage 30 and is at atmospheric pressure, the front and rear mask pistons 4.5 and the booster piston 19 are moved by the force of the return spring 12 of each mask piston. Each is held at the backward limit.

Further, in this case, the input hydraulic pressure chamber 20 is introduced with hydraulic pressure from the hydraulic pump 24 or the pressure accumulator 25, and this hydraulic pressure acts on the front surface of the large diameter piston portion 19h of the booster piston 19. 19 is held at the backward limit.

The hydraulic pressure introduced into the input hydraulic pressure chamber 20 passes through the oil passage 34 to the first valve chamber 33. is also introduced into the inlet valve Vi and acts on the valve body 38 of the inlet valve Vi, but according to the above equation (1), the pressure of the valve body 3 due to the hydraulic pressure is
The retreating force of the valve body 8 , that is, the valve closing force, is suppressed to zero or extremely small, and the valve closing force of the valve body 48 is controlled by the set load of the valve closing spring 39 . Since the umbrella-shaped valve body 38 has extremely high obstructing properties, it can be securely seated on the valve seat 38 with the above-mentioned valve-closing force, and can prevent hydraulic pressure from leaking from the input hydraulic chamber 20 to the output hydraulic chamber 21. .

Now, when the brake pedal P is depressed to brake the automobile, the input rod 51 moves forward and first pushes the valve body 46 of the outlet valve Vo against the force of the valve opening spring 47 via the guide piston 49. , the valve is seated on the valve seat 45, and the Yamaguchi valve Vof is placed in the closed state. Next, the valve body 38 of the inlet valve Vi is pushed through the valve body 46 to separate it from the valve seat 37, thereby opening the large mouth valve Vi. At this time, as described above, the closing force of the valve body 38 due to the hydraulic pressure when the large mouth valve Vi is in the closed state is zero or extremely small, so the initial movement resistance of the valve body 38 is slight.

When the outlet valve Vo closes and the large mouth valve Vi opens, the output hydraulic chamber 21 is disconnected from the oil tank 2, and the input hydraulic chamber 20 is connected to the first valve chamber 33. Since the hydraulic pressure introduced into the output hydraulic pressure chamber 21 enters the output hydraulic pressure chamber 21 through the valve hole 36, the annular groove 43, and the oil passage 42, the booster piston 19 is moved to the large diameter piston portion 19b.
The rear end face receives the hydraulic pressure and advances, and the rear mask piston 5 is advanced via the reaction mechanism R and the output rod 58.

In this way, the mask cylinder M is actuated with a booster force.

The hydraulic pressure introduced into the output hydraulic pressure chamber 21 further enters the second valve chamber 332 through the oil passage 35 and acts on the second shaft portion 38h of the valve body 38 and the valve body 46, but according to the above formula (2). Therefore, the retraction force of the valve body 46 due to the oil pressure can be suppressed to zero or extremely small.

While the booster piston 19 is pushing the rear mask piston 5, the pressure receiving screw 1 56 is
The operation reaction force of the cylinder M is received from the rear mask piston 5 to compress the elastic piston 55, and a part of the compression force is transferred to the valve body 38 via the reaction piston 57, and further to the valve body 46 and the guide piston. 49 to the input rod 51, which allows the driver to sense the magnitude of the braking force. The boost ratio at this time is that the cross-sectional area of the pressure receiving piston 56 is A1, and the cross-sectional area of the reaction piston 51 is A2C. A valve seat formed at the boundary between a valve chamber that communicates with the hydraulic chamber and a valve hole that opens into the valve chamber and communicates with the output hydraulic chamber; A valve that cooperates with the valve seat to open and close the valve hole. It consists of an umbrella-shaped valve body housed in a chamber; and a valve-closing spring that biases the valve body in the closing direction, and one end of the valve body is provided with an oil-tight seal and a guide cylinder that forms the front end wall of the valve chamber. A first shaft part is slidably supported, and a second shaft part interlocked with the input rod is protruded from the other end. Since the cross-sectional area is set to be equal to or slightly smaller than the cross-sectional area at the point, the occluding property when the inlet valve is closed is good, and the initial resistance of the valve body when closing the artificial valve can be kept small. As a result, it is possible to prevent oil pressure from leaking from the input oil pressure chamber, contributing to energy saving, and improving the operational feeling.

[Brief explanation of the drawing]

The drawing is a longitudinal side view showing one embodiment of the present invention. B... Booster, M... Master cylinder, R...
Recoil mechanism, Vi...inlet valve, Vo...outlet valve 2...
- Oil tank, 12... Return spring, 16... Booster cylinder, 18... Cylinder hole, 19... Booster piston, 20... Input hydraulic chamber, 21... Output hydraulic chamber,
22... Outlet chamber, 23... Supply oil path, 24... Hydraulic pump as a hydraulic pressure source, 25... Pressure accumulator, 30...
・Return oil path, 331...first valve chamber, 332...second
Valve chamber, 34...oil passage, 35...oil passage, 36...valve hole, 37...valve seat, 38...valve body, 38α...first
Shaft portion, 38b...Second shaft portion, 39...Valve closing spring, 4
0... Guide tube, 42... Oil path, 43... Annular groove,
44...Oil passage, 45...Valve seat, 46...Valve body, 4
6a... Shaft portion, 47... Valve opening spring, 49... Guide piston, 51... Input rod

Claims (1)

[Claims] a booster cylinder; a booster piston that is slid into a cylinder hole of the booster cylinder and partitions its interior into a front input hydraulic chamber connected to a hydraulic pressure source; and a rear output hydraulic chamber having a larger pressure receiving area; an input rod that is connected to the booster piston so as to be able to move forward and backward; the input rod is provided in an oil passage connecting the input and output hydraulic chambers, and is configured to close when the input rod retreats and open when the input rod moves forward; an inlet valve interlocked with the input rod; and an outlet valve interlocked with the input rod, which is provided in an oil passage connecting the output hydraulic pressure chamber and the oil tank and opens when the input rod moves backward, and closes when the input rod moves forward. In the hydraulic booster, the inlet valve is formed at a boundary between a valve chamber formed in the booster piston and communicating with the input hydraulic chamber, and a valve hole opening into the valve chamber and communicating with the output hydraulic chamber. a valve seat; an umbrella-shaped valve body accommodated in the valve chamber to open and close the valve hole in cooperation with the valve seat; and a valve closing spring that biases the valve body in a closing direction. A first shaft part is supported at one end of the valve body in an oil-tight and slidable manner by a guide tube constituting the front end wall of the valve chamber, and a second shaft part is connected to the input rod at the other end. A hydraulic type, characterized in that each of the shaft portions is provided in a protruding manner, and the cross-sectional area of the first shaft portion is set to be equal to or slightly smaller than the cross-sectional area at the point where the valve body is seated on the valve seat. booster.