JPS60191864A - Assembled body consisting of master cylinder and hydraulic booster - Google Patents

Abstract

PURPOSE:To aim at the promotion of shortening in an assembled body, by making the front end part of a booster piston belonging to a hydraulic booster so as to be holdable in a part of a cylinder hole of a master cylinder, while installing an annular body, which is slidingly fitted in the said piston oiltightly, in a rear part of the cylinder hole. CONSTITUTION:An assembled body bearing the above caption consists of a master cylinder M and a hydraulic booster B to be connected to a rear end of the cylinder body 1. The hydraulic booster B comprises a front input hydraulic chamber 20 to be interconnected to a hydraulic source by a booster piston 19 housed inside a cylinder hole 18 via an oil passage 23 and a boostercylinder 16 having a rear output hydraulic chamber 21 being relatively large in a pressure receiving area. Interconnection, interception and the like between input and output hydraulic chambers 20 and 21 are all controlled by a valve piston 35. In this case, the booster piston 19 is made up of both small and large diametral piston parts 19a, 19b and a rod part 19c, and the large diametral piston part 19a is constituted to be insertable into the cylinder body 1. In this connection, the insertion part should be sealed with an annular body 15.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an assembly of a mask cylinder and a hydraulic booster;
In particular, the booster cylinder connected to the rear end of the cylinder body of the mask cylinder; the input hydraulic chamber at the front that slides into the cylinder hole of the booster cylinder and whose interior is connected to the hydraulic source; and the pressure receiving area is larger than that. a booster cylinder which is divided into a rear output hydraulic chamber and connected to a mask histone which is slidably fitted into a cylinder hole of the cylinder body; a booster cylinder which is slidably fitted to the booster piston to allow communication and isolation between the input and output hydraulic chambers; and a valve piston that is manually operated to shut off and communicate between the output hydraulic chamber and the oil tank.

Conventionally, in such assemblies, the mask and booster cylinders were provided with dedicated cylinder holes that individually guided the mask and booster pistons of different diameters throughout their sliding strokes, so that the overall length of the assembly was Because of this, when installed in a narrow engine room of a car, for example, to operate the hydraulic brake of a car, it may interfere with the engine or its accessories, making installation difficult.

Therefore, the present invention shortens the cylinder hole of the booster cylinder by allowing a portion of the cylinder hole of the mask cylinder to accommodate the front end of the advancing booster piston, thereby providing the assembly with a short overall length and simple structure. The purpose is to provide

In order to achieve this object, the present invention includes a cylinder hole in the cylinder body consisting of a small diameter hole in the front part and a large diameter hole larger in diameter than the front part of the booster piston. The booster piston comprises a small-diameter piston portion that slides into the small-diameter hole and a large-diameter piston portion that slides into the large-diameter hole, and the booster piston is positioned close to the large-diameter piston portion so that it enters the large-diameter hole when the booster piston moves forward; A rear end is supported between the cylinder body and the booster cylinder to define a retraction limit of the mask piston, and the cylinder is slidably engaged with the front part of the booster piston in an oil-tight manner to form a front end wall of the input hydraulic pressure chamber. It is characterized by having an annular body interposed therein.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. First, in FIG. 1, 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. , the lower half of which is connected to a front oil reservoir 2. by a partition wall 2α. and a rear oil sump 2□.

The cylinder hole 3 of the cylinder body 1 has a small diameter hole 3a 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 3a has a front oil reservoir 2,
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 5a and a large-diameter piston portion 5b.

A supply oil chamber γ is defined in the large diameter hole 3b by both piston portions 5α and 515, and this oil chamber 1 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 5a.
A relief 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. A through hole 11 that communicates the replenishment oil chamber 7 with the back of the piston cup 9 is bored in the portion 5α.

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 port 10, hydraulic pressure is generated in the rear hydraulic chamber 6.
and a brake hydraulic circuit (not shown) in communication with the brake hydraulic pressure 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 2□ 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 reservoir 2□ from the relief port 10.

When the front mask piston 4 is withdrawn to raise the pressure in the rear hydraulic chamber 6, oil in the front oil reservoir 2□ is replenished into the front hydraulic chamber, but such a hydraulic pressure generation mechanism and oil replenishment mechanism are Since it is substantially the same as the rear hydraulic chamber 6 side, detailed explanation thereof will be omitted.

As clearly shown in FIG. 2, a booster cylinder 16 of a hydraulic booster H is connected to the rear end of the cylinder body 1 of the mask cylinder M with an annular body 15 in between, and the cylinder body 1 and the booster cylinder 16 are connected by bolts 17. tied together.

Here, the small diameter hole 3a of the cylinder hole 3 of the mask cylinder M
1, the diameter of the large diameter hole 3b is D2, and the annular body 15
The inner diameter of the booster cylinder 16 is D3, and the cylinder hole 18 of the booster cylinder 16 is
Assuming that the diameter of is D4, these dimensions are set in the following relationship.

Dl<D3 D4 D2 The booster piston 19 has a small diameter piston part 19α at the front, a large diameter piston part 19A at the rear, and a large diameter piston part 19.
The small-diameter piston portion 19α and the large-diameter piston portion 19b are oil-tightly slidably fitted into the annular body 15 and the cylinder hole 18 of the booster cylinder 16, respectively, and the rod portion 19C projects from the rear end surface of the booster cylinder 16. It penetrates the rear end wall of the cylinder 16 in an oil-tight manner and projects to the outside. In order to define the retraction limit of the booster piston 19, a stepped portion 1 capable of supporting the rear end surface of the large diameter piston portion 19h is provided.
8a is formed at the rear end of the cylinder hole 18.

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 part 19A define an input hydraulic chamber 20 therebetween, and the large diameter piston part 19A and the rear end wall of the booster cylinder 16 define an output hydraulic chamber 21 therebetween. to be accomplished. This output hydraulic chamber 2
1 is naturally formed to have a larger pressure receiving area than the input hydraulic pressure chamber 20. Further, the large diameter piston portion 5h of the rear mask piston 5 of the mask cylinder M and the small diameter piston portion 19a 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 .

A large mouth valve 26 and an outlet valve 27 are arranged in parallel on the booster piston 19.

The large mouth valve 26 includes a cylindrical valve chamber 29 formed along the axial direction of the booster vis-ton 19 in the middle of an oil passage 28 that communicates between the output hydraulic chambers 20 and 21, and a rear end of this valve chamber 29. A spherical valve body 30 that opens and closes the oil passage 28 in cooperation with a valve seat formed on the wall, a valve spring 31 that biases the valve body 30 in the closing direction within the valve chamber 29, and Valve body 3 against force
The actuating rod 32 can be opened at 0, making it more normally closed. The operating rod 32 is fitted into the booster piston 19 so as to be slidable in its axial direction, and its rear end protrudes into the output hydraulic chamber 21 .

The outlet valve 27 is composed of a valve cylinder 33 fitted to the booster piston 19 (7) on the axis thereof, and a valve piston 35 slidably engaged with the inner hole of the valve cylinder 33, that is, the valve hole 34. , the rear end of the valve piston 35 is connected to the dash rod 3
6 to the brake pedal 3γ. Valve cylinder 33
has an outlet port 38 connected to the output hydraulic chamber 21, and the valve piston 35 is connected to the outlet port 38 according to its advance/retreat.
It has an annular groove 39 that blocks and communicates with the annular groove 39, and an oil passage 40 that is connected to the annular groove 39. This oil passage 40 is connected to the outlet chamber 22 through an oil passage 41 formed in the booster piston 19.
The outlet chamber 22 is connected to a radial groove 42 (see FIG. 4) provided on the front end surface of the guide ring 15, an annular oil passage 43 formed on the rear end of the cylinder body 1, and the oil passage 43. The oil tank 2 is connected to the oil tank 2 through a return oil passage 44.

In the output hydraulic chamber 21, a pin 45 is fitted into the valve piston 35 so as to be perpendicular to its axis. Both ends of this pin 450 are connected to the valve cylinder 33 and the rod portion 19 of the booster piston 19.
It passes through long axial holes 46 and 47 drilled in C, respectively, and projects onto the outer circumferential surface of the rod portion 19c, and the projecting end portions 45a and 45α are formed in a truncated conical shape. This surface protruding end portion 45α.

45, z, as shown in FIG. 3, there is a connecting hole 49. of the two-part interlocking ring 48 that is slidably engaged with the outer circumferential surface of the rod portion 19C.
49 is fitted, and in order to maintain the connection state between the pin 45 and the interlocking ring 48, a coil spring 5 is installed around the outer periphery of the interlocking ring 48.
0 is wound. Therefore, the interlocking ring 48 is connected to the valve piston 35.
The actuating rod 32 of the inlet valve 26 is pushed forward in response to the forward movement of the inlet valve 26 .

In order to define the retraction limit of the valve piston 35, a circlip 51 capable of supporting the rear end surface is engaged with the inner circumferential surface of the rod portion 19C, and a return spring 52 that urges the valve piston 35 in the retraction direction is connected to the rod. It is compressed between the portion 19C and the valve piston 35. This return spring 52 also has the function of maintaining the fixed position of the valve cylinder 33 to the booster piston 19.

Here, when the booster piston 19 and the valve piston 35 are at their backward limits, LI is the forward stroke of the valve piston 35 required to close the outlet valve 27, and LI is the forward stroke of the valve piston 35 required to close the outlet valve 27.
If the forward stroke of the valve piston 35 required to open the valve 6 is L2, it is set as Ll<L2.

The booster piston 19 has a large diameter hole 53 opening on the front surface thereof, and a small diameter hole 54 extending from the large diameter hole 53 to the valve hole 34. An elastic piston 55 and a pressure-receiving piston 56 having the same diameter are slidably fitted together, and a reaction piston 57 whose both ends can come into contact with opposing surfaces of the valve piston 35 and the elastic piston 55 is fitted into the small-diameter hole 54 .

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 a reaction mechanism R that transmits the operational reaction force of the mask cylinder M to the valve piston 35.

Next, the operation of this embodiment will be explained.

When the brake pedal 37 is not actuated, the valve piston 35 is held at the retracting limit by the force of the return spring 52 together with the interlocking ring 48 as shown, and the annular groove 39 occupies a position communicating with the outlet port 38, so that the outlet valve 27 is in an open state. On the other hand, in the large mouth valve 26, the operating rod 32 is connected to the interlocking ring 4.
8 and the valve body 30 is seated on the valve seat of the valve chamber 29 by the force of the valve spring 31, so that the valve is in the closed state. Therefore, between the person and the output hydraulic chamber 20.21 is 7
20 valve 26, and the output hydraulic chamber 21 is connected to the outlet port 38, the annular groove 39, the oil passage 40, and the outlet chamber 22.
, communicates with the oil tank 2 via the radial groove 42, the annular oil passage 43, and the return oil passage 44 and is at atmospheric pressure.
The rear mask piston 4.5 and the booster piston 19 are held in their respective retraction limits by the force of the return spring 12 of each mask piston.

Furthermore, in this case, the input hydraulic pressure chamber 20 receives hydraulic pressure from the hydraulic pump 24 or the pressure accumulator 26, and this hydraulic pressure acts on the front surface of the large diameter piston portion 19.6 of the booster piston 19. booster piston 19
is held at the backward limit.

Further, since the spherical valve body 30 has a high obstructing property, leakage of pressure oil from the input hydraulic chamber 20 to the output hydraulic chamber 21 can be reliably prevented.

Now, when the brake pedal 37 is depressed to brake the automobile, the valve piston 35 and the interlocking ring 48 are pushed forward from the brake pedal 37 via the bushing rod 36, and from the relationship Ll<L2, the annular groove 39 is first pushed forward. Outlet port 3
8, that is, the outlet valve 27 is closed. The interlocking ring 48 then comes into contact with the rear end of the operating rod 32 and pushes it forward, thereby separating the valve body 30 from the valve seat, that is, opening the inlet valve 26. As a result, the output hydraulic chamber 21 is disconnected from the oil tank 2, and the hydraulic pump 24 or the pressure accumulator 25 is cut off.
The hydraulic pressure introduced into the input hydraulic chamber 20 from the input hydraulic pressure chamber 20 is also introduced into the output hydraulic chamber 21 through the oil passage 28 and the valve chamber 29, and the booster piston 19 receives the hydraulic pressure on its rear end surface and moves forward. and the rear mask piston 5 via the output rod 58
move forward. That is, the mask cylinder M is actuated with increased force.

Then, the booster piston 19 advances its front end into the large diameter hole 3h of the mask cylinder M so as to track the rear mask piston 5. In this way, the large diameter hole 3b is
In addition to guiding the large diameter piston portion 5b of the rear mask piston 5, it also serves to receive the front end portion of the booster piston 19 moving forward.

While the booster piston 19 is pushing the rear mask piston 5, the pressure receiving piston 56 receives the operational reaction force of the mask cylinder AI from the rear mask piston 5 and operates to compress the elastic piston 55, and the compression force is A portion of the braking force is fed back to the brake piston 35 via the reaction piston 57 and further to the brake pedal 37 via the bushing rod 36, allowing the driver to sense the magnitude of the braking force. The boosting ratio at this time is such that the cross-sectional area of the pressure receiving piston 56 is 51, the cross-sectional area of the reaction piston 57 is This function not only contributes to a reduction in the number of parts, but also allows the rear mask piston 5 and booster piston 19 to be connected to each other. allows for close placement.

In the illustrated example, the oil tank for the hydraulic booster B is 4 g of oil for the mask cylinder AI! 2 is shared, but an oil tank exclusively for hydraulic booster B may be provided.

As described above, according to the present invention, the cylinder hole of the cylinder body of the mask cylinder is composed of a small diameter hole in the front part and a large diameter hole larger in diameter than the front part of the booster piston, and the mask piston is configured with the small diameter hole in the front part. consisting of a small-diameter piston part that slides into the large-diameter hole and a large-diameter piston part that slides into the large-diameter hole,
Since the booster piston is placed close to the large-diameter piston part so that it enters the large-diameter hole when the booster piston moves forward, when the booster piston is activated,
The front end of the booster piston is received in the cylinder hole of the mask cylinder, and the length of the cylinder hole of the booster cylinder is shortened by the amount of reception compared to the conventional one.
As a result, an assembly with a reduced overall length can be obtained.

Moreover, between the cylinder body and the booster cylinder,
An annular body is inserted to support the rear end of the mask piston to define the retraction limit, and to slide in an oil-tight manner with the front part of the booster piston to form the front end wall of the input hydraulic chamber. A stopper function for the master piston and a wall function for defining the input hydraulic chamber are provided, which not only reduces the number of parts and simplifies the structure, but also
It becomes possible to arrange the mask piston and the booster piston close to each other, and the assembly can be further shortened, so that the assembly can be easily installed even in a narrow engine room of an automobile.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional side view showing one embodiment of the assembly of the present invention, FIG. 2 is an enlarged view of its main parts, FIG. 3 is an enlarged sectional view along the river-phase line of FIG. 1, and FIG. 1 is a sectional view taken along the line IV-1v in FIG. 1. FIG. M-゛・Mask cylinder, B...Hydraulic booster, R・
...Reaction mechanism 1...Cylinder body, 2...Oil tank, 3...Cylinder hole, 3 ct, 3H...Small and large diameter hole, 5...
Mask piston, 5a, 5b... Small and large diameter piston portion, 16... Booster cylinder, 15... Annular body, 1
8... Cylinder hole, 19... Booster piston, 1
9α, 19b...small. Large diameter piston part, 20.21...Person, output hydraulic chamber, 2
4... Hydraulic pump as a hydraulic source, 25... Pressure accumulator, 26.27... Person, outlet valve, 35... Valve piston, 37... Brake pedal, 48... Interlocking ring, 58
...Output rod patent applicant Nissin Kogyo Co., Ltd.

Claims (1)

[Claims] A booster cylinder connected to the rear end of the cylinder body of the mask cylinder; a front input hydraulic chamber that is slid into the cylinder hole of the booster cylinder and whose interior is connected to a hydraulic source; and a rear input hydraulic chamber that has a larger pressure receiving area. a booster piston connected to a mask piston that is partitioned into an output hydraulic chamber and slidably fitted into a cylinder hole of the cylinder body; a valve piston that is manually operated to isolate and communicate between the output hydraulic chamber and the oil tank;
In the mask cylinder and hydraulic booster assembly, the cylinder hole of the cylinder body is composed of a small diameter hole in the front part and a large diameter hole larger in diameter than the front part of the booster piston, and the mask piston includes: The booster piston is comprised of a small diameter piston part that slides into the small diameter hole and a large diameter piston part that slides into the large diameter hole, and the booster piston is configured to move into the large diameter piston part so that it enters the large diameter hole when the booster piston moves forward. The cylinder body and the booster cylinder are disposed close to each other, and the rear end of the mask piston is supported to define the retraction limit of the mask piston, and the front end of the booster piston is oil-tight with the front end of the booster piston to form a front end wall of the input hydraulic pressure chamber. An assembly of a mask cylinder and a hydraulic booster, characterized in that an annular body that slides on the mask cylinder and a hydraulic booster is interposed therein.