JPH0225736Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a quick-filling master cylinder that rapidly fills the hydraulic chamber with pressure oil when the piston first moves, thereby quickly removing play in operating equipment such as wheel brakes. .

Conventionally, as described in Japanese Utility Model Application Publication No. 57-135459, this type of master cylinder has been provided with a stepped cylinder hole in the cylinder body consisting of a small diameter part at the front and a large diameter part at the rear. A piston having a small diameter piston part and a large diameter piston part corresponding to the small diameter part and the large diameter part is slid into this cylinder hole, and a hydraulic chamber is formed in front of the small diameter piston part at a predetermined retracted position of the piston. A relief port that opens to the oil tank and a supply port that opens to the replenishment oil chamber formed between the small-diameter piston portion and the large-diameter piston portion are connected to the oil tank through an oil passage formed in the longitudinal direction of the cylinder body. A valve device is interposed in this oil passage, and the valve device includes a pressure-responsive valve that opens when the pressure in the replenishment oil chamber rises to a predetermined value or more, and a pressure-responsive valve that opens the replenishment oil from the oil tank. Equipped with a one-way valve that allows oil to flow only in one direction into the chamber, and a bypass with high flow resistance that bypasses the pressure-responsive valve and the one-way valve and communicates between the oil tank and the replenishment oil chamber. something is known.

However, in the conventional master cylinder, the valve chamber of the valve device is bored in the cylinder body from the direction intersecting the oil passage, so that the pressure-responsive valve and the one-way valve can open and close in the intersecting direction. Since both valves are located in the valve chamber, the valve device becomes large and the flow of oil is not smooth.In addition, the openings of the valve chamber and the oil passage that open to the outside of the cylinder body must be blind plugged. Since the blind plugs must be closed by the plugs, it takes time and effort to install the blind plugs, and the number of parts increases, making it uneconomical.

Furthermore, this type of master cylinder is required to have a one-way valve with good sealing properties to ensure rapid filling operations, and one-way valves and pressure-responsive valves that are easy to assemble. Ru.

The purpose of the present invention is to provide a simple and effective quick-filling master cylinder that can solve the above-mentioned problems and satisfy the above-mentioned requirements. A stepped cylinder hole is provided, and a piston having a small diameter piston part and a large diameter piston part corresponding to the small diameter part and the large diameter part is slid into this cylinder hole, and when the piston is at a predetermined retracted position, the small diameter A relief port that opens into a hydraulic chamber formed in front of the piston part and a supply port that opens into a replenishment oil chamber formed between the small diameter piston part and the large diameter piston part are provided in the cylinder body in the longitudinal direction thereof. communicates with the oil tank through the formed oil passage,
A valve device is interposed in the oil passage, and the valve device includes:
a pressure-responsive valve that opens when the pressure in the replenishment oil chamber increases to a predetermined value or more; a one-way valve that allows oil to flow only in one direction from the oil tank to the replenishment oil chamber; and the pressure-response valve. and a bypass with high flow resistance that bypasses the one-way valve and communicates between the oil tank and the relief port, wherein the oil passage is connected to the rear end surface of the cylinder body. A valve chamber for accommodating the valve device is provided near the outer opening of the oil passage, and a blind plug is attached to the outer opening of the oil passage as an end wall of the valve chamber. , the one-way valve has a valve seat formed on an inner end surface of the valve chamber, and a hemispherical end surface facing the valve seat, and an oil passage is provided between the valve seat and the peripheral surface of the valve chamber for the oil passage. A hollow cylindrical valve body that opens and closes in the direction of the center line of the passage, and a valve spring that is disposed between the cylindrical valve body and the blind stopper and biases the cylindrical valve body toward the valve seat. The pressure-responsive valve, which includes a valve body that opens and closes in the direction of the center line of the oil passage, is incorporated into the cylindrical valve body, and the bypass is connected to the oil passage and the inner periphery of the cylindrical valve body. and an orifice formed in the cylindrical valve body to communicate between the oil passage and the inner circumference.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The master cylinder shown in FIG. 1 is a tandem type for a two-system hydraulic brake, and the cylinder hole ₁ of the cylinder body M has the piston 2 The pistons 2 ₂ are slid together in series, and a front hydraulic chamber 3 1 is defined between the front piston 2 ₁ and the front end wall of the cylinder hole ₁ , and a rear hydraulic chamber 3 ₂ is defined between both pistons 2 ₁ and 2 ₂ . and those hydraulic chambers 3 ₁ , 3
_Two brake hydraulic circuits are connected to the two output ports 4 ₁ and 4 ₂ , respectively. Each piston 2 ₁ ,
2 ₂ is provided with elastic piston cups 5 ₁ and 5 ₂ at the front end, respectively, and has an annular groove in the middle, and these grooves provide front and rear supply oil chambers 6 ₁ and 6 ₂ in the cylinder hole 1. define. Oil holes 7 that communicate these oil chambers 6 ₁ , 6 ₂ with the backs of the piston cups 5 ₁ , 5 _2
1 and 7 ₂ are provided on each piston 2 ₁ and 2 ₂ .

A return spring 8 ₁ that urges the front piston 2 ₁ in the backward direction is housed in the front hydraulic chamber 3 ₁ , and a piston spacing regulating device 9 for determining the backward limit of the front piston 2 ₁ is installed between the front and rear hydraulic chambers 3 1 . The rear piston 2 2 is provided between the pistons 2 ₁ and _{2 2} , and its retraction limit is determined by its contact with a stop ring 10 that is secured to the inner wall of the cylinder hole 1 .

The piston spacing regulating device 9 is the rear piston 2 ₂
Fixed seat plate 1 fixed by bolts 11 to the front end of
2, and a movable seat plate 13 provided to be able to slide back and forth on the bolt 11 within a limited stroke range.
and a return spring 8 compressed between the seat plates 12 and 13.
₂ , and the set load of the return spring ₈₂ is set to be larger than that of the return spring ₈₁ .
Therefore, the return spring ₈₂ is normally attached to both seat plates 12 and 13.
The distance between the pistons 2 1 and 2 2 is widened to the maximum, and both pistons 2 ₁ and 2 ₂ are held at predetermined retraction limits by cooperation with the return spring 8 ₁ .

A cylindrical auxiliary oil tank 14 is integrally provided on the upper side of the cylinder body M adjacent to the front hydraulic chamber ₃₁ , and a transparent synthetic resin main oil tank 15 is connected to the upper end of the auxiliary oil tank 14. Thus, an oil tank R is configured.
The main oil tank 15 is equipped with a known float-type oil volume reduction alarm device 16, which is configured to close a reed switch 18 when the oil level in the main oil tank 15 drops below a specified level. , a warning lamp (not shown) is lit.

The auxiliary oil tank 14 is divided into front and rear oil reservoir chambers 20 ₁ and 20 ₂ by a partition wall 19 that is integrated with the cylinder body M. When each piston 2 ₁ and 2 ₂ is at a predetermined retraction limit, the front The oil reservoir chamber 20 ₁ communicates with the front hydraulic chamber 3 ₁ and the front supply oil chamber 6 ₁ via the relief port 21 ₁ and the supply port 22 ₁ , respectively, and extends rearward from the rear oil reservoir chamber 20 ₂ . An oil passage 23 formed in the longitudinal direction of the cylinder body M communicates with the rear hydraulic chamber 3 ₂ and the rear supply oil chamber 6 ₂ via the relief port 21 ₂ and the supply port 22 ₂ , respectively.

The rear piston 2 ₂ has a small-diameter piston portion 2 a and a large-diameter piston portion 2 b that are arranged in front and behind with a rear replenishment oil chamber 6 ₂ in between, and the piston cup 5 ₂ and the oil hole 7 ₂ are provided in the small-diameter piston portion 2 a. It is being
Corresponding to these piston parts 2a and 2b, the rear part of the cylinder hole 1 is also formed in a stepped manner so as to have a small diameter part 1a and a large diameter part 1b.

The oil passage 23 is bored into the cylinder body M from the rear end surface, and a cylindrical valve chamber 25 is formed in the oil passage 23 near the outer opening 24 . The outer opening 24 of the oil passage 23 is closed by a blind plug 26 screwed therein. Therefore, this blind plug 26 also functions as an end wall of the valve chamber 25.

A valve device 27 is provided within the valve chamber 25 to control communication between the rear oil reservoir chamber 20 ₂ and the rear replenishment oil chamber 6 ₂ .

As clearly shown in FIG. 2, this valve device 27 has a hollow cylindrical valve body 28 that is open at both ends. It is fitted into the valve chamber 25 via the valve chamber 25 so as to be slidable in the direction of the center line of the oil passage 23 . As a result, the valve chamber 25
An oil passage p is formed between the inner peripheral surface and the cylindrical valve body 28. The supply port 22 ₂ communicates with the spring housing portion 30 between the cylindrical valve body 28 and the blind plug 26 .
In this spring accommodating portion 30, a valve spring 31 is compressed between the cylindrical valve body 28 and the blind plug 26, and the elastic force of the valve spring 31 causes the hemispherical end surface 28a of the cylindrical valve body 28 to It is seated on a tapered valve seat 32 formed on the inner end surface of the valve chamber 25 on the chamber ₂₀₂ side. These cylindrical valve body 28, valve seat 32, and valve spring 31 are
A one-way valve 33 is configured that allows oil to flow only in one direction from the rear oil reservoir chamber 20 ₂ to the rear supply oil chamber 6 ₂ .

The relief port 21 ₂ communicates with the oil passage p around the cylindrical valve body 28 .

In the cylindrical valve body 28, the annular body 3 has a valve seat 34 on the inner circumferential surface of the opening opening into the spring accommodating part 30.
5 is fitted, and a valve seat 34 is fitted within the cylindrical valve body 28.
A spherical valve body 36 that opens and closes in the direction of the center line of the oil passage 23 and a valve spring 37 that springs the valve body 36 toward the valve seat 34 are disposed. The seat 34 and the valve spring 37 constitute a pressure-responsive valve 38 that opens when the pressure in the rear replenishment oil chamber ₆₂ rises above a predetermined value.

Further, an orifice 39 is formed on the peripheral wall of the cylindrical valve body 28 near the valve seat 32, and the inner circumference of the cylindrical valve body 28 is formed between the orifice 39 and a rib 40 protruding from the inner circumferential surface of the cylindrical valve body 28. It communicates with the oil passage p around the cylindrical valve body 28 via the gap 41 . The inner periphery of the cylindrical valve body 28, the oil passage p and the orifice 39
constitutes a bypass 42 with high flow resistance that communicates between the rear oil reservoir chamber 20 ₂ and the relief port 21 ₂ by bypassing the one-way valve 33 and the pressure-responsive valve 38 .

Next, to explain the operation of this embodiment, when the rear piston 2 ₂ is advanced from the retreated position shown in the figure by operating the brake pedal, both pistons 2 ₁ and 2 ₂ compress the return springs 8 ₁ and 8 _2, respectively. move forward while
Each piston cup 5 ₁ , 5 ₂ is a relief port 21
After closing the pistons ₁ and 21 ₂ , hydraulic pressure is generated in each hydraulic chamber 3 ₁ and 3 ₂ according to the amount of advance of each piston 2 ₁ and 2 ₂ ,
These hydraulic pressures can be output from the output ports 4 ₁ and 4 ₂ to operate the corresponding wheel brakes.

During this time, especially as the large diameter piston portion 2b of the rear piston ₂₂ moves forward, the volume of the rear replenishing oil chamber ₆₂ is reduced, so that the oil discharged from the oil chamber ₆₂ flows through the large flow path of the orifice 39. Resistance and cylindrical valve body 2
The hemispherical end surface 28a of the piston cup 52 is seated on the tapered valve seat 32, which provides a reliable seal, so that the oil hardly returns to the oil passage 23 side and passes through the oil hole ₇₂ to the piston cup ₅₂ . It is fed under pressure to the rear hydraulic chamber ₃₂ while bending the outer circumferential portion forward. In this way, the rear hydraulic chamber 3 ₂ is quickly filled with pressure oil, and as a result, output hydraulic pressure is generated early in each output port 4 ₁ , 4 ₂ , and play in each wheel brake is quickly removed, and these can be operated without any time delay.

When the pressure in the rear hydraulic chamber ₃₂ increases and the hydraulic pressure in the rear replenishing oil chamber ₆₂ rises above the specified opening pressure of the pressure-responsive valve 38, the spherical valve body 36 is moved against the force of the valve spring 37 to the left in FIG. In order to open the pressure-responsive valve 38, the oil discharged from the rear supply oil chamber ₆₂ passes through the supply port ₂₂₂ , the pressure-responsive valve 38, and the oil passage 23 to the rear oil sump chamber. 20 ₂ , thereby suppressing an excessive pressure rise in the rear supply oil chamber 6 ₂ , so that the forward movement of the rear piston 2 ₂ is not hindered.

When the operating force from the brake pedal is released, both the pistons 2 ₁ and 2 ₂ are returned to the predetermined retraction limit by the return force of the return springs 8 ₁ and 8 ₂ , respectively, and in the return process, the front and rear hydraulic chambers 3 ₁ and 3 ₂ is depressurized, and the outer peripheries of the piston cups 5 ₁ and 5 ₂ 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 front oil reservoir chamber 20 ₁ Oil is supplied to the front hydraulic chamber 3 ₁ through the supply port 22 ₁ , the front supply oil chamber 6 ₁ and the oil hole 7 ₁ , and the spring housing section 3 .
0 oil is supplied to the supply port 22 ₂ , rear supply oil chamber 6 ₂
and is supplied to the rear hydraulic chamber ₃₂ through the oil hole ₇₂ ,
Accordingly, the oil in the rear oil reservoir chamber ₂₀₂ is transferred to the cylindrical valve body 28.
In order to open the one-way valve 33 by moving it to the right in FIG. 2 against the force of the valve spring 31, the oil flows through the oil passage 23 and the oil passage p around the cylindrical valve body 28. It passes smoothly and efficiently flows into the spring accommodating portion 30.

When each piston 2 ₁ , 2 ₂ returns to the predetermined retreat position, the relief ports 21 ₁ , 21 ₂ are connected to the hydraulic chambers 3 ₁ , 2 2 .
3 _{and 2} , the excess oil supply in the front hydraulic chamber 3 ₁ is released to the front oil reservoir chamber 20 ₁ through the relief port 21 ₁ , and the excess oil supply in the rear hydraulic chamber 3 ₂ is also released. The oil is discharged to the rear oil sump chamber 20 ₂ through the relief port 21 ₂ and the bypass 42 (see arrow in FIG. 2).

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

As described above, according to the present invention, a valve chamber is formed in the oil passage, and the cylindrical valve body of the one-way valve and the valve body of the pressure-responsive valve are disposed in the valve chamber at the center of the oil passage. Since the valve can be opened and closed in the linear direction, it contributes to miniaturization of the valve device, and also forms a smooth oil flow to improve oil replenishment and return efficiency.

In addition, since the end wall of the valve chamber also serves as the blind plug for the oil passage, the man-hours for installing the blind plug can be halved compared to the conventional method, and the number of parts can also be halved, improving economic efficiency. .

Furthermore, in one-way valves, the hemispherical end surface of the cylindrical valve body is seated on the valve seat, making it possible to maintain good sealing between the cylindrical valve body and the valve seat, thereby ensuring rapid filling operations. can be done.

Furthermore, since the pressure-responsive valve is incorporated into the cylindrical valve body of the one-way valve to form both valves into a unit, it is possible to downsize the valve device and improve the ease of assembling the two valves.

Furthermore, since the bypass is formed using the cylindrical valve body and its inner and outer peripheral parts, the structure of the bypass can be simplified.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional side view of a master cylinder showing an embodiment of the present invention, and FIG. 2 is an enlarged sectional view of the main part of the master cylinder around the valve device. M...Cylinder body, p...Oil path, R...Oil tank, 1...Cylinder hole, 1a...Small diameter part, 1b...
...large diameter part, 2 ₂ ... rear piston, 2a ... small diameter piston part, 2b ... large diameter piston part, 3 ₂ ...
Rear hydraulic chamber, 6 ₂ ... Rear supply oil chamber, 20 ₂ ... Rear oil reservoir chamber, 21 ₂ ... Relief port, 22 ₂ ...
Supply port, 23... Oil passage, 24... Outer opening, 25... Valve chamber, 26... Blind plug, 27...
Valve device, 28... Cylindrical valve body, 28a... Hemispherical end surface, 31... Valve spring, 32... Valve seat, 33... One-way valve, 36... Valve body, 38... Pressure responsive valve, 3
9... Orifice, 42... Bypass.

Claims (1)

[Scope of utility model registration request] The cylinder body M is provided with a stepped cylinder hole 1 consisting of a small diameter portion 1a at the front and a large diameter portion 1b at the rear. 2a and a piston 2 ₂ having a large diameter piston portion 2b,
At a predetermined retreat position of the piston ₂₂ , a relief port ₂₁₂ opens to the hydraulic chamber ₃₂ formed in front of the small diameter piston part 2a, and a supply is formed between the small diameter piston part 2a and the large diameter piston part 2b. A supply port 22 ₂ that opens into the oil chamber 6 ₂ is communicated with the oil tank R via an oil passage 23 formed in the longitudinal direction of the cylinder body M, and a valve device 27 is connected to the oil passage 23 . The valve device 27 includes a pressure-responsive valve 38 that opens when the pressure in the replenishment oil chamber 6 ₂ rises to a predetermined value or more, and a one-way valve 38 from the oil tank R to the replenishment oil chamber 6 ₂ . a one-way valve 33 that allows oil to flow only in the pressure-responsive valve 3;
8 and the one-way valve 33 to bypass the oil tank R.
and a bypass 42 with a large flow resistance that communicates between the oil passage 23 and the relief port 21 ₂ .
is bored from the rear end surface of the cylinder body M, and a valve chamber 25 for accommodating the valve device 27 is provided near the outer opening 24 in the oil passage 23, and a blind plug is used as an end wall of the valve chamber 25. 26 is attached to the outer opening 24 of the oil passage 23, and the one-way valve 33 is attached to the valve chamber 25.
It has a valve seat 32 formed on an inner end surface of the valve seat 32 and a hemispherical end surface 28a facing the valve seat 32, and an oil passage p exists between the inner peripheral surface of the valve chamber 25 and the oil passage 2.
Hollow cylindrical valve body 2 that opens and closes in the direction of the center line of 3.
8, and a valve spring 31 that is disposed between the cylindrical valve body 28 and the blind plug 26 and biases the cylindrical valve body 28 toward the valve seat 32.
The pressure-responsive valve 38 equipped with a valve body 36 that opens and closes in the direction of the center line of the oil passage 23 is incorporated therein, and the bypass 42 is connected to the oil passage p and the inner circumference of the cylindrical valve body 28. and an orifice 39 formed in the cylindrical valve body 28 to communicate between the oil passage p and the inner peripheral portion.