JPS60151162A - Speedy filling type master cylinder - Google Patents

Abstract

PURPOSE:To improve the working-oil filling efficiency by forming an annular oil passage between a small-diameter piston part and the large-diameter hole of a cylinder opening when a master cylinder piston is at a retreat position and allowing a hydraulic chamber and a supplied-oil chamber to communicate through the annular oil passage. CONSTITUTION:The rear-part piston 3 of a master cylinder M is equipped with a small-diameter piston part 35 at the front and a large-diameter piston part 36 at the rear. A rear-part hydraulic chamber 5 is formed in a small-diameter hole 32 in front of the small-diameter piston part 36, and a rear-part supplied-oil chamber 11 is formed between the both piston parts 35 and 36. A piston cup 9 is installed onto the front edge surface of the small-diameter piston part 35 is separated from the small-diameter hole 32 when the rear-part piston 3 is at a retreat position, and an annular oil passage 37 is opened to allow the rear-part hydraulic chamber 5 to communicate to the rear-part supplied-oil chamber 11. The piston cup 9 closely contacts with the small-diameter hole 32 when the piston 3 is at an advance position, and the annular passage 37 is closed and the both chambers 5 and 11 are cut-off.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a quick-filling mask cylinder that rapidly fills a hydraulic fluid into a hydraulic chamber when a piston is first moved, thereby quickly removing play in operating equipment such as wheel brakes. .

As such a type of mask cylinder, for example, Japanese Patent Application Laid-open No. 57
As described in Publication No. 22949, a stepped cylinder hole consisting of a small diameter hole at the front and a large diameter hole at the rear is provided in the cylinder body, and this cylinder hole has holes corresponding to the small diameter hole and the large diameter hole. A piston having a small diameter piston part and a large diameter piston part is slid together, an elastic piston cup is attached to the front end surface of the piston, and a relief opens into a hydraulic chamber formed in front of the small diameter piston part at a predetermined retracted position of the piston. A pressure-responsive valve that opens when the pressure in the replenishment oil chamber rises to a predetermined value or more is installed between the boat and the replenishment oil chamber formed between the small diameter screw I/n part and the large diameter piston part. It is conventionally known to connect the

However, in the above mask cylinder, when the pressure in the replenishment oil chamber increases due to the advancement of the large-diameter piston portion of the piston, the outer circumferential portion of the piston cup is bent forward by that pressure, and the outer circumferential surface of the piston cup and the cylinder Since the hydraulic oil is rapidly filled into the hydraulic chamber through the gap between the inner peripheral surfaces of the small-diameter holes and the oil hole formed in the small-diameter piston, the flow path resistance is large and the filling efficiency of the hydraulic oil is low. There is a problem. Furthermore, since the outer periphery of the screw I-cane knob rubs against the opening of the relief boat, there is a problem in that the outer periphery is damaged and the durability of the piston canopy is impaired.

An object of the present invention is to provide the above-mentioned rapid filling type mask cylinder capable of solving the above-mentioned problem, and the cylinder body is provided with a stage (=J cylinder hole) consisting of a small diameter hole at the front and a large diameter hole at the rear. In the piston housed in the cylinder hole, an annular oil passage is defined between the large-diameter piston portion that slides into the large-diameter hole and the inner peripheral surface of the large-diameter hole in the retracted position of the piston, and the small-diameter piston part in the forward position. A small diameter piston part that slides into the hole is provided,
A hydraulic chamber is formed in front of the small-diameter piston part in the small-diameter hole, and a supply oil chamber is formed between the small-diameter piston part and the large-diameter piston part. An elastic piston cup is mounted on the front end surface of the small diameter piston part, which opens to connect the hydraulic chamber to the replenishment oil chamber, and in the forward position, closes the annular oil passage and isolates the hydraulic chamber from the replenishment oil chamber by coming into close contact with the small diameter hole. A supporting means for supporting the small-diameter piston part concentrically with the small-diameter hole is provided in the small-diameter hole, and the Zaburai boat that opens into the replenishment oil chamber is opened when the pressure in the replenishment oil chamber rises to a predetermined value or more. It is connected to an oil tank via a pressure-responsive valve.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. The mask cylinder shown in FIG. The pistons 3 are slid together in series, and a front hydraulic chamber 4 is defined between the front piston 2 and the front end wall of the cylinder hole 1, and a rear hydraulic chamber 5 is defined between both pistons 2.3. , 5 output portlo.

Two brake hydraulic circuits are connected to 7, respectively. Each piston 2, 3 is equipped with an elastic piston cup 8.9 made of rubber on its front end surface, and has an annular ring 16 in the middle, and these grooves are inserted into the cylinder hole l to form front and rear supply oil chambers 10. .11. An oil hole 1 is provided in the front piston 2 for communicating the front supply oil chamber 10 with the back of the piston cup 8. The communication structure between the rear hydraulic chamber 5 and the rear replenishment oil chamber 11 will be described later.

A return spring 13 for biasing the front piston 2 in the backward direction is housed in the curved hydraulic chamber 4, and a piston spacing regulating device 14 for determining the backward limit of the nT piston 2 is installed in the hydraulic chamber 4.
, the rear piston 3 is provided between the rear pistons 2 and 3, and the retraction limit of the rear piston 3 is determined by its contact with a stop ring 15 that is secured to the inner wall of the cylinder hole 1.

Corner regulation between pistons 11. The device 14 includes a fixed seat plate 17 fixed to the front end of the rear piston 3 by a bolt 16, a movable seat plate 18 provided so as to be able to slide back and forth on the bolt 16 within a limited stroke range, and both. Seat plate 17.18
The return spring 19 is compressed in between, and the spring load of the return spring 19 is set to be larger than that of the return spring 13. Therefore, the return spring 19 is normally attached to both seat plates 1.
The distance of 7.18° is maximized and, in cooperation with the return spring 13, both pistons 2.3 are held at their respective predetermined retraction limits.

A cylindrical auxiliary oil tank 20 is integrally provided on the upper side of the cylinder body M adjacent to the front hydraulic chamber 4, and a main oil tank 21 made of transparent synthetic resin is connected to the upper end of the auxiliary oil tank 20. is configured. The main oil tank 21 is equipped with a known float-type oil volume reduction alarm device 22, which is configured to close a reed switch 24 when the oil level in the main oil tank 21 drops below a specified level. , a warning lamp (not shown) is turned on.

The auxiliary oil tank 20 is divided into front and rear oil reservoir chambers 26 and 27 by a partition wall 25 that is integrated with the cylinder body M. When each piston 2 and 3 is located at a predetermined retraction limit, the front oil reservoir chamber 26 communicates with the front hydraulic chamber 4 and the front supply oil chamber 10 via the relief boat 28 and the supply boat 29, respectively, and extends rearward from the rear oil sump chamber 27,
An oil passage 3o formed in the longitudinal direction of the cylinder body M communicates with the rear supply oil chamber 11 via a supply boat 31.

The rear piston 3 side of the cylinder hole 1 is formed in a stepped manner by a front small diameter hole 32 and a rear large diameter hole 33 having the same inner diameter as the part where the piston 2 is slid together. The rear piston 3 includes a small diameter piston part 35 at the front and a large diameter piston part 36 at the rear, and the rear hydraulic chamber 5 is formed in front of the small diameter piston part 36 in the small diameter hole 32. is always slid into the large diameter hole 33, and the rear replenishment oil chamber 11 is formed between both piston parts 35 and 36.

The small-diameter piston portion 35 defines an annular oil passage 37 within the constricted portion 34 of the large-diameter hole 33 between the small-diameter piston portion 35 and the inner peripheral surface thereof when the rear piston 3 is in the retracted position, and slides into the small-diameter hole 32 when the rear piston 3 is in the forward position.

The piston cup 9 is attached to the front end surface of the small-diameter piston portion 35, and when the rear piston 3 is in the retracted position, the piston cup 9 separates from the small-diameter hole 32 to open the annular oil passage 37 and move the rear hydraulic chamber 5 to the rear. It communicates with the replenishment oil chamber 11, and in the forward position, closes the annular oil passage 37 by coming into close contact with the small diameter hole 32, thereby blocking the rear hydraulic chamber 5 from the rear replenishment oil chamber 11. The open portion of the small diameter hole 32 on the annular oil passage 37 side is formed in a piston cup guiding taper surface 38 whose diameter gradually increases from the small diameter hole 32 toward the annular oil passage 37, as clearly shown in FIG.

The hollow head side of the bolt 16 in the piston spacing regulating device 14 is slid into the center hole 39 of the front piston 2, whereby the small diameter piston portion 35 is supported by the front piston 2 via the bolt 16.

Therefore, the bolt 16 and the front piston 2 constitute a support means for supporting the small diameter piston portion 35 concentrically with the small diameter hole 32. The inner peripheral surface of the opening of the hollow head of the bolt 16 is formed into a tool retaining hole 16a having a hexagonal cross section.

The oil passage 30 is bored into the cylinder body M from the rear end surface, and a cylindrical valve chamber 40 is formed in the oil passage 30 near the outer opening.

The outer opening of the oil passage 30 is closed by a blind plug 41 screwed therein. Therefore, this blind plug 41 also functions as an end wall of the valve chamber 40.

A valve device 42 that controls communication between the rear oil reservoir chamber 27 and the rear replenishment oil chamber 11 is provided within the valve chamber 40 .

As clearly shown in FIG. 3, this valve device 42 has a hollow cylindrical valve body 43 with both ends open.
It is fitted into the valve chamber 40 so as to be slidable in the direction of the center line of the oil passage 30 via a plurality of protrusions 44 protruding from the outer peripheral surface.

The Zaburibau 1, 31 communicates with a spring accommodating portion 45 between the cylindrical valve body 43 and the blind plug 41, and a valve spring 46 is compressed in this accommodating portion 31, and the elastic force of the valve spring 46 causes the cylindrical shape to be compressed. The hemispherical end surface of the valve body 43 can be seated on a tapered valve seat 47 formed at the mouth edge of the communication hole on the rear oil reservoir chamber 27 side. These cylindrical valve body 43, valve seat 47, and valve spring 46 constitute a one-way valve 48 that allows oil to flow only in one direction from the rear oil reservoir chamber 27 to the rear replenishment oil chamber 11.

An annular body 50 having a valve seat 49 is fitted into the inner circumferential surface of the opening of the cylindrical valve body 43 that opens into the spring accommodating portion 45 , and a spherical body 50 having a valve seat 49 is fitted inside the cylindrical valve body 43 . A valve body 51 and a valve spring 52 that springs the valve body 51 toward the valve seat 49.
The spherical valve body 51, the valve body 49, and the valve spring 52 constitute a pressure-responsive valve 53 that opens when the pressure in the rear oil chamber 11 rises to a predetermined value or higher.

Further, an orifice 54 is formed in the peripheral wall of the cylindrical valve body 43 near the valve seat 47 of the valve chamber 40.
The outer circumference and inner circumference of the cylindrical valve body 43 are connected via a gap 56 between ribs 55 protruding from the inner circumferential surface of the cylindrical valve body 43.
do. The inner and outer peripheral portions of the cylindrical valve body 43 and the orifice 54 serve as a bypass with a high flow resistance that communicates between the rear oil sump chamber 27 and the relief boat 31 by bypassing the one-way valve 48 and the pressure-responsive valve 53. Configure.

Next, the operation of this embodiment will be explained. When the rear piston 3 is moved forward from the retreated position shown in the figure by operating the brake pedal, both pistons 2 and 3 move forward while compressing the return springs 13 and 19, respectively. After the rear piston cup 8 closes the relief boat 28 and the rear piston cup 9 comes into close contact with the tapered surface 38, hydraulic pressure is generated in each hydraulic chamber 4, 5 according to the amount of advance of each piston 2, 3. , these hydraulic pressures can be outputted from the output ports 1-6 and 7 to operate the corresponding wheel brakes.

During this period, especially when the rear piston 3 moves forward, the hydraulic oil in the rear replenishment oil chamber 11 hardly returns to the oil passage 30 side due to the large flow resistance of the bypass 57 and the closing of the pressure-responsive valve 53. The hydraulic oil is supplied to the rear hydraulic chamber 5 through the oil passage 37, and the rear hydraulic chamber 5 is rapidly filled with hydraulic oil.As a result, the output hydraulic pressure is generated early in the Toyama Kaportro 7, and the play in each wheel brake is reduced. They can be quickly removed and activated without time delay.

After the rear piston cup 37 comes into close contact with the tapered surface 38, when the oil pressure in the rear replenishment oil chamber 11 rises above the specified opening pressure of the pressure-responsive valve 52, the f7Y-shaped valve body 51 is moved by the valve spring 5.
Pressure-responsive valve 53 is moved to the left in Figure 3 against the force of 2.
In order to open the valve, the oil discharged from the rear supply oil chamber 11 is returned to the rear oil sump chamber 27 through the supply bow h31, the pressure-responsive valve 53, and the oil passage 30.31. Since an excessive increase in pressure in the replenishment oil chamber 11 is suppressed, the forward movement of the rear piston 3 is not hindered.

If you release the operating force from the brake pedal, both pistons 2
．． 3 are returned to a predetermined retraction limit by the return force of return springs 13 and 19, respectively, and in the return process, the front and rear hydraulic chambers 4,
5 is depressurized, the outer peripheries of the piston cups 8 and 9 are bent forward due to the pressure difference between the front and rear, creating a gap between them and the inner surface of the cylinder hole 1. As a result, the hydraulic oil in the front oil reservoir chamber 26 is transferred to the piston cup 1. ~29, The front hydraulic chamber 4 is supplied through the front supply oil chamber lO and the oil hole 12, and the hydraulic oil in the spring housing section 45 is supplied to the supply boat 31, the rear supply oil chamber 11, and the annular oil passage 3.
7 and the above-mentioned gap, and the hydraulic oil in the rear oil reservoir chamber 27 is supplied to the rear hydraulic chamber 5 via the cylindrical valve body 43 and the valve spring 4.
In order to open the one-way valve 48 against the force of 6, the hydraulic oil smoothly passes through the oil passage 30 and the outer circumference of the cylindrical valve body 43 and efficiently flows into the spring housing portion 45. .

When each piston 2, 3 returns to the retracted position, the relief boat 28 opens into the front hydraulic chamber 4, so that the excess supply of hydraulic oil in the front hydraulic chamber 4 is transferred from the Excess supply of hydraulic oil released into the reservoir chamber 26 and in the rear hydraulic chamber 5 is transferred to the annular oil passage 37 and bypass 57 opened by the piston cup 9 being disengaged from the small diameter hole 32.
The oil is discharged to the rear oil sump chamber 27 through the oil tank.

It goes without saying that the present invention is not limited to the above tandem type mask cylinder, but can also be applied to a single piston type mask cylinder.

As described above, according to the present invention, the annular oil passage 37 is defined between the small diameter piston portion 35 and the large diameter hole 33 of the cylinder hole 1 at the retracted position of the piston 3, and the annular oil passage 37 is connected to the piston cup 9. Since the oil pressure chamber 5 is opened and communicated with the replenishment oil chamber 11, the replenishment oil chamber 11 is opened at the beginning of the movement of the piston 3.
of hydraulic oil can be quickly filled into the hydraulic chamber 5 through the annular oil passage 37, thereby generating output hydraulic pressure in the output boat early, quickly removing play in the operating equipment, and eliminating any time delay. can be activated.

In this case, since the flow path resistance of the annular oil passage 37 to the hydraulic oil is small, the filling efficiency of the hydraulic oil into the hydraulic chamber 5 can be improved. The fact that this flow path resistance is small means that the pressing force of the operating pedal is small when the piston 3 moves forward, which improves the feeling of pressing the pedal.
There is also the advantage of increasing

Furthermore, by providing the annular oil passage 37, the relief boat can be omitted, and thereby the piston cup 9
The durability of the piston cup 9 can be improved by eliminating one of the causes of damage to the piston cup.

Furthermore, the small diameter piston portion 35 of the piston 3 is supported by the supporting means 2.
16, the piston 3 is supported concentrically with the small diameter hole 32 of the cylinder hole 1, so that even if there is a gap between the small diameter piston portion 35 and the large diameter hole 33, the piston 3 can be supported concentrically with the small diameter hole 32 of the cylinder hole 1 without defining the annular oil passage 37. can operate smoothly.

Furthermore, since the hydraulic chamber 5 is not rapidly filled with hydraulic oil due to the pressure increase in the replenishment oil chamber 11, the opening pressure of the pressure-responsive valve 53 can be set low, and the size of the valve can be reduced. Responsiveness to the pressure in the replenishment oil chamber 11 can be improved.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention; FIG. 1 is an overall longitudinal sectional front view, FIG. 2 is an enlarged longitudinal sectional front view of an annular oil passage portion, and FIG.
FIG. 3 is an enlarged longitudinal sectional front view of the pressure-responsive valve portion. M...Cylinder body, R...Oil tank, ■...Cylinder hole, 2.16...Front piston and bolt constituting the support means, 3...Rear screw I/N, 5...・Rear hydraulic chamber, 9... Screw;
33... Large diameter hole, 35... Small diameter piston part, 36...
...Large diameter piston part, 37...Annular oil passage, 53...
Pressure-responsive valve patent applicant Nissin Kogyo Co., Ltd.

Claims (1)

[Claims] The cylinder body (M) is provided with a stepped cylinder hole (1) consisting of a small diameter hole (32) at the front and a large diameter hole (33) at the rear, and a piston ( 3),
A large diameter piston portion (36) that slides into the large diameter hole (33).
In the retracted position of the piston (3), the large diameter hole (33
) is provided with a small diameter piston part (35) defining an annular oil passage (37) between the inner peripheral surface thereof and slidingly engaging with the small diameter hole (32) in the forward position; A hydraulic chamber (5) is provided in front of the small diameter screw part (35) within the
Further, a replenishment oil chamber (11) is formed between the small diameter piston part (35) and the large diameter piston part (36), and when the piston (3) is in the retracted position, it is removed from the small diameter hole (32). The annular oil passage (37) is opened to communicate the hydraulic chamber (5) with the supply oil chamber (11), and in the forward position, the annular oil passage (37) is closed by coming into close contact with the small diameter hole (32). An elastic piston cup (9) that isolates the hydraulic chamber (5) from the replenishment oil chamber (11) is attached to the front end surface of the small diameter piston part (35), and the small diameter piston part (35) is connected to the small diameter piston part (35). The support means (2, 16) that supports the small diameter hole (32) concentrically is provided in the small diameter hole (32) and opens into the replenishment oil chamber (11).
- (31) is connected to an oil tank (R) via a pressure-responsive valve (53) that opens when the pressure in the replenishment oil chamber (11) rises above a predetermined value.