JPS6088672A - Hydraulic booster device for master cylinder - Google Patents

Abstract

PURPOSE:To make an oil tank for a booster unnecessary so that a hydraulic booster device is made compact, by providing such an arrangement that a return oil passage for discharging hydraulic pressure in a hydraulic output chamber of a booster is formed in a master cylinder so that the passage may be communicated with an oil tank for the master cylinder. CONSTITUTION:Upon resting of a booster B, an output hydraulic chamber 24 of the booster B is communicated with an oil tank 2 for a master cylinder M through a rear port 35 and a passage 36 in a valve piston 26, a small oil chamber 32 and an output port 38 in a rear piston 72, and a hydraulic supply chamber 102 and a supply port 42. With this arrangement, since there is provided such a return passage for discharging hydraulic pressure in the hydraulic output chamber 24 into the oil tank 2 for the master cylinder M, an oil tank exclusively used for a booster device B may be eliminated so that the device may be made compact with its entirety.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydraulic booster used for hydraulically boosting a mask cylinder for operating a hydraulic brake of an automobile, for example.

Conventionally, this type of hydraulic booster has been provided with its own oil reservoir, which has caused the problem of increasing the size of the entire device.

The present invention was proposed in view of this problem, and the present invention is integrated with the mask cylinder to form a unit, and the oil tank originally provided with the mask cylinder can be shared, resulting in a simple and compact structure. It is an object of the present invention to provide the above-mentioned hydraulic booster.

To achieve this objective, according to the present invention, a hydraulic booster includes a booster cylinder integrally connected to the rear part of a cylinder body of a mask cylinder having an oil tank in the upper part; and a suction port communicating with the oil tank. a hydraulic pump; the booster cylinder is slidably fitted into the booster cylinder and its interior is divided into a front input hydraulic chamber connected to a discharge port of the hydraulic pump, and a rear output hydraulic chamber having a larger pressure receiving area; A booster piston integrally connected to the rear part of the piston of the mask cylinder; and a valve hole provided in the booster piston is slidably connected to communicate and disconnect between the input and output hydraulic chambers, and between the output hydraulic chamber and the oil tank. a valve piston that is artificially moved forward and backward to shut off and communicate with a series of return oil passages;
The return oil passage is formed within the mask cylinder.

An embodiment of the present invention will be described below with reference to the drawings.

M is 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, and the inside is divided into a front oil tank 2 and a rear oil tank by a partition wall 2a in the lower half. These oil reservoirs 21.
2□ are the front 1717-fubots 3□ and 32, respectively.
It communicates with the cylinder hole 1a of the cylinder body 1 via supply bows 1' and 41 and 42 at the rear. A front piston 71 and a rear piston 72 are slidably fitted into the cylinder hole 1α.

In the cylinder hole 1a, a front hydraulic chamber 81 is defined between the front piston 7□ and the front end wall of the cylinder hole 1a, and a rear hydraulic chamber 82 is defined between both pistons 70, 72, and these hydraulic chambers 81.8 ．． , communicate with each of the two brake hydraulic circuits via an output boat (not shown). Each piston 71.

72 has a piston cup 9 at the front end. ．． 92, and the middle part has a small diameter and an annular replenishment oil chamber 1 is provided around the outer circumference.
, 102 are formed respectively, and the oil chambers io, , 102 are respectively formed.
The through holes ii, , ii□ which communicate the io2 with the back of the piston cup 91° 920 are connected to each piston 7, . It is provided at the front end of 72.

The front hydraulic chamber 81 accommodates a front return spring 12□ that urges the front piston 7 in the backward direction, and the rear hydraulic chamber 82
A rear return spring 12□ that springs the rear piston 1□ in the backward direction and a spacing device 14 that restricts the spring from elongating beyond a certain level are housed in the rear return spring 12□. The spacing device 14 includes a pair of front and rear movable and fixed seats 15 and 16 that receive both ends of the rear return spring 12□, and a support shaft 17 that is attached to the rear piston 72 and slidably supports the movable seat 15. The support shaft 17 has an enlarged head 17a that restricts forward movement of the movable seat 15. Therefore, although the support shaft 17 allows the movable seat body 15 to approach the rear piston 72,
The ampulla 1 is spaced a certain distance or more from the rear piston 72.
7Q to restrict the maximum distance between the movable seat body 15 and the rear piston 72, and this restriction gives the return spring 122 an extension limit.

The above is a conventional configuration, and the hydraulic booster B of the present invention is connected to this mask cylinder M, and these are integrated into a unit. The configuration of the booster B will be explained next.

At the rear of the cylinder body 1 of the mask cylinder M, a booster cylinder 20 having a diameter larger than the cylinder hole 1a (Z) is integrally installed, and at the rear of the rear piston 7□, the cylinder hole 20a is installed. A booster piston 21 that slides on the booster cylinder 20 is integrally connected to the rear end of the booster cylinder 20. An end plug 22 that restricts the backward limit of the booster piston 21 is screwed onto the rear end of the booster cylinder 20.

In the cylinder hole 20α, the booster piston 21 is
The middle part has a small diameter and an annular input hydraulic chamber 23 is provided on the outer periphery.
An output hydraulic chamber 24 is defined between the end plug 22 and the end plug 22, and the pressure receiving area of the output hydraulic chamber 24 is larger than that of the input hydraulic chamber 23. In addition, cylinder holes 1α, 20a
Because of the difference in size, the pressure receiving area of the booster piston 21 is larger than the pressure receiving area of the rear piston 72 in the input hydraulic chamber 23.

A series of valve holes 25 are bored in the rear piston 7□ and the booster piston 21 along their axes, starting from the rear end of the booster piston 21 and ending at the middle of the rear piston 7□. A valve piston 26 passing through the end plug 22 is slidably engaged with the valve piston 26, and a brake pedal 2B is connected to the rear end of the valve piston 26 via a bushing rod 27.

A retainer plate 30 is attached to the end plug 22 to hold a seal member 29 that is in contact with the outer periphery of the valve piston 26.
is fitted from the output hydraulic chamber 24 side, and a stopper flange 31 is formed in the middle of the valve piston 26 to abut against the retainer plate 30 and restrict the backward limit of the valve piston 26. A small oil chamber 32 is defined in the front part of the valve hole 25 by the front end surface of the valve pinuton 26, and a return spring 33 for urging the valve piston 26 in the backward direction is contracted in the small oil chamber 32.

The forward limit of the valve piston 26 relative to the booster piston 21 is regulated by the front end of the valve piston 26 coming into contact with the front end wall of the small oil chamber 32 .

The valve piston 26 has an annular front port 34 and a rear port 3 which are spaced apart from each other on the outer periphery of the valve piston 26.
5, and an oil passage 36 that communicates both ports 1-34, 35 with each other and communicates them with the small oil chamber 32, and the rear port 35 is always open to the output hydraulic chamber 24.

On the other hand, the booster piston 21 has an inlet port 37 extending from the input hydraulic chamber 23 to the valve hole 25 corresponding to the front port 34, and an inlet port 37 extending from the rear piston 72 to the replenishing oil chamber 10.
Two outlet ports 38 are each drilled therein.

The valve piston 26 is divided into two parts: a spool part 26α having front and rear ports 34 and 35, and a rond part 26b having a stopper flange 31 and supported by the end plug 22.
Both parts 26 (1, 26b) are always kept in contact with each other by the elastic force of the return spring 33.

The input hydraulic chamber 23 is connected to the oil tank 2 of the mask cylinder M by an oil passage 40, and the oil passage 40 includes a hydraulic pump 41 capable of pumping the reservoir of the oil tank 2 to the input hydraulic chamber 23, and the pump 4.1. An electromagnetic on-off valve 42 located downstream of is interposed, and a pressure accumulator 43 is connected between the hydraulic pump 41 and the on-off valve 42.

The electromagnetic on-off valve 42 has a control switch 45 interposed in an electric circuit connecting the power source 44 when the solenoid is energized to be closed in conjunction with depression of the brake pedal 28 . Also,
The hydraulic pump 41 is reversely driven by an electric motor 46, and an electric circuit connecting the motor 46 and the power source 44 is configured to respond when the internal pressure of the pressure accumulator 43 falls below a certain value. A pressure nut 47 is inserted which closes when the pressure is closed. Note that 48 is a main switch that is linked to the opening and closing of the ignition switch of the automobile.

Next, the operation of this embodiment will be explained. First, the main switch 48 is opened in conjunction with the opening operation of the car's ignition switch.
When closed, the electric motor 46 operates and the hydraulic pump 41
can be driven, and the hydraulic pressure can be accumulated in the pressure accumulator 43 up to a predetermined pressure.

When the brake pedal 28 is in the inactive state, as shown in the figure,
Since the control switch 45 is open, the electromagnetic on-off valve 4
2 is in a closed state. Further, the valve piston 26 is held at the retracting limit by the stopper flange 31 coming into contact with the retainer plate 30, and the front port 34 is connected to the inlet boat 3.
The front end edge of the valve piston 26 leaves the outlet port 38 half open and communicates between the port 38 and the small oil chamber 32. Therefore, the output hydraulic pressure chamber 24 communicates with the oil tank 2 via the rear port 35, oil passage 36, small oil chamber 32, outlet port 38, replenishment oil chamber 102, and supply port 4□, and is brought to atmospheric pressure. , rear piston 7I.

72 and Bunuta piston 21 are each return spring 12
．． ．． It is held in the retracted position by a force of 122.

Now, when the brake pedal 28 is depressed to brake the automobile, the control switch 45 is closed and the on-off valve 42 is opened. At the same time, from the brake pedal 28 to the bushing rod 2
7, the valve piston 26 is pushed forward, first the front edge of the valve piston 26 blocking the outlet boat, and then the front port 34 is moved into communication with the inlet port 37. As a result, hydraulic pressure is introduced into the input hydraulic chamber 23 from the pressure accumulator 43 and the hydraulic pump 41, and the hydraulic pressure is supplied to the output hydraulic chamber 24 through the inlet boat 3γ, the front port 34, the oil passage 36, and the rear port 35. As a result, the Bunuta Pinuton 21 moves forward in response to the hydraulic pressure, and the front and rear Binuton 7. .

7□ and their return springs 121. 122 is moved forward while being compressed. and each piston cup 9. ,9
2 passes through the relief ports 3□, 32, and then each piston 7, . Hydraulic pressure is generated in each hydraulic chamber 81.8□ in accordance with the forward movement of brake lever 72, and both brake hydraulic circuits can be operated simultaneously.

The hydraulic pressure introduced into the output hydraulic chamber 24 also acts as a reaction force on the valve piston 26 to suppress it in the backward direction.
This reaction force is fed back to the brake pedal 28 via the bushing rod 27, allowing the driver to sense the magnitude of the braking force. The boost ratio in this case is the piston 7. .

72 pressure receiving area S1 and the rod portion 26b of the valve piston 26
is determined by the ratio of the cross-sectional area S2 to the cross-sectional area S2.
There is an advantage that the boost ratio can be changed by simply replacing 6b with one of a different diameter.

Therefore, if there is no need to change the boost ratio, the valve piston 26 may be an integral type.

Next, when the brake pedal 28 is released to release the brake, the valve piston 26 is moved back by the force of the return spring 32, and the front port 34 is isolated from the inlet port 37 in the same way as in the non-operating state described above. position, and the front end edge of the valve piston 26 is returned to the position where the small oil chamber 32 and the outlet boat 38 communicate with each other.
6. The oil is discharged into the oil tank 2 through the small oil chamber 32, the outlet boat 38, the supply oil chamber 102, and the oil ports 1 and 42. Therefore, the small oil chamber 3 formed in the mask cylinder M
2, the outlet boat 38, the replenishment oil chamber 10□, and the supply boat 42 correspond to the return oil path of the present invention.

On the other hand, while the on-off valve 42 is open, the input hydraulic chamber 23
Since hydraulic pressure continues to be introduced into the input hydraulic chamber 2, this hydraulic pressure is input to the input hydraulic chamber 2.
A retraction force is applied to the booster piston 21 by acting on the difference in pressure receiving area between the rear piston 72 and the booster piston 21 at 3. As a result, the booster piston 21 follows the backward motion of the brake pedal 28, and accordingly the front, rear pistons 7, . 72 retreats with the force of return springs 121 and 122. When the booster piston 21 reaches its backward limit and the brake pedal 28 returns to its initial non-operating position, the control switch 45 is opened, and the on-off valve 42 is closed to cut off the oil passage 40.

During this time, due to the retirement of both pistons 71.7□, the hydraulic chamber 8
．． ．． If a vacuum is generated at 82, the piston cup 91.92
The outer periphery of the oil sump 21 is bent forward due to the pressure difference between the front and rear, creating a gap between the inner surface of the cylinder hole a and the oil sump 21.
．． Hydraulic oil in 2□ is connected to supply port 1-4. ．． 4. ,, Hydraulic oil flows into the hydraulic chambers 81 and 82 through the replenishment oil chambers 101 and 102 and the through holes 111 and 112, respectively, and is replenished with hydraulic oil.If excessive replenishment is performed at that time, the excess amount is transferred to the IJ.
IJ-Fubot 3. , 3 degrees and returned to oil tank 2.

As described above, according to the present invention, the booster cylinder and booster piston of the hydraulic booster are integrally connected to the cylinder body of the mask cylinder and the rear part of the pinuton, respectively, and the output hydraulic chamber of the booster is Since a return oil passage for discharging hydraulic pressure is formed in the mask cylinder so as to communicate with the oil tank of the mask cylinder, the booster is integrated into a unit with the master cylinder, and the oil tank of the mask cylinder is connected to the oil tank of the booster. Therefore, an oil tank dedicated to the booster is not required, and as a result, the structure of the booster can be simplified and made more compact. Moreover, since there is no need for external piping to form the return oil passage, it is advantageous in terms of ease of assembly and safety.

[Brief explanation of drawings]

The drawing is a longitudinal side view showing one embodiment of the present invention. B... Booster, /l/... Inside the mask cylinder.
・Cylinder body, 2...Oil tank, 4□...Supply boat, 72...Rear beerton as piston of mask cylinder, 102...Replenishment oil chamber, 20...Booster cylinder, 21...Booster Piston, 23...
Input hydraulic chamber, 24... Output hydraulic chamber, 25... Valve hole,
26...Valve piston, 32...Small oil chamber, 39...Outlet port, 41...Hydraulic pump, 4□, 102.3
2.38...Return oil route patent applicant Nissin Kogyo Co., Ltd.

Claims (1)

[Claims] a booster cylinder that is integrally connected to the rear of the cylinder body of the mask cylinder with an oil tank at the top; a hydraulic pump that communicates the suction port with the oil tank; A booster pinuton is divided into a front input hydraulic chamber connected to the discharge port of the mask cylinder, and a rear output hydraulic chamber with a large pressure receiving area, and is integrally connected to the rear of the piston of the mask cylinder; Artificial advance/retreat operation so as to slide into a provided valve hole to effect communication and isolation between the input and output hydraulic chambers, as well as isolation and communication between the output hydraulic chamber and the return oil path connected to the oil tank. A hydraulic booster for a mask cylinder, comprising a valve pinuton; the return oil passage is formed in the master cylinder.