JP3445541B2 - Center valve type master cylinder - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a center valve type master cylinder used in a hydraulic brake system for vehicles and the like.

[0002]

2. Description of the Related Art As a conventional technique of this kind, Japanese Patent Laid-Open No.
There is a center valve type master cylinder described in Japanese Patent No. 226329.

That is, the above publication discloses a cylinder body having a cylinder hole, a piston slidably inserted into the cylinder hole to define a hydraulic chamber on one end side, the hydraulic chamber and a hydraulic fluid reservoir. A center valve mechanism disposed in a communication passage provided between the center passage mechanism and the center passage mechanism for connecting or disconnecting the communication passage. The center valve mechanism is formed so as to penetrate in the radial direction of the piston. Part, a pin member that is inserted into the insertion hole and is movable relative to the piston in the axial direction of the piston, and the insertion hole of the piston that supports the axial end portion of the pin member. An annular support member that fits in the region where the piston is formed, and a stem that is fitted in an inner hole that is formed in the axial direction of the piston and that communicates the hydraulic chamber with the insertion hole, and that can engage with the pin member. And body, a center-valve type master cylinder the valve body and a seating capable valve seat is described.

[0004]

However, in the conventional center valve type master cylinder, since the annular support member is supported by the outer peripheral portion of the piston, the hydraulic fluid reservoir is connected to the hydraulic pressure chamber. The passage area between the inner diameter of the annular support member and the outer diameter of the piston, which is configured as a part of the communication passage, is much smaller than the passage area between the outer diameter of the annular support member and the cylinder bore inner diameter. . Therefore, a throttle effect of the fluid flow is generated in this portion, and a rapid fluid flow of the hydraulic fluid from the hydraulic fluid reservoir side toward the hydraulic pressure chamber side is generated due to a negative pressure tendency in the hydraulic pressure chamber generated when the brake operation is suddenly released. In this case, the throttling effect may hinder the rapid supply of liquid to the hydraulic chamber, which may delay the return of the piston.

Further, in recent years, as the brake control of the vehicle, in addition to the braking operation of the driver, the state of the running vehicle is detected, and an automatic brake for automatically applying a predetermined braking force to each wheel based on the detection result. The system is being developed. There are several systems in this automatic brake system, for example, hydraulic fluid pressurization that supplies the hydraulic pressure generated by sucking and pressurizing the hydraulic fluid through the communication passage and the hydraulic chamber to the vehicle brake device side. There are systems with means (hydraulic pumps).

When the above-mentioned prior art master cylinder is applied to this system, a liquid flow throttling effect occurs in the passage between the inner diameter of the annular support member and the outer diameter of the piston, and the working fluid suction / pressurizing means ( There is a risk that the working fluid may not be sufficiently sucked by the hydraulic pump.

The present invention has been made in view of the above problems, and sufficiently secures a gap between the annular support member that supports the pin member and the piston to prevent a delay in returning of the piston when the driver releases the brake operation. It is another object of the present invention to provide a center valve type master cylinder that does not hinder the suction action of hydraulic fluid when applied to an automatic braking system.

[0008]

Means for Solving the Problems The above problems include a cylinder body having a cylinder hole, a piston slidably inserted into the cylinder hole to define a hydraulic chamber on one end side, and the hydraulic chamber. A center valve mechanism arranged in a communication passage provided between the hydraulic fluid reservoir and the communication passage to connect or disconnect the communication passage.
An insertion hole penetrating in the radial direction of the piston and forming a part of the communication passage, a pin member inserted into the insertion hole and movable relative to the piston in the axial direction of the piston, and the pin. An annular support member that supports an axial end portion of a member and fits into a portion of the piston where the insertion hole is formed, and an inner hole that is formed in the axial direction of the piston and that communicates the hydraulic chamber with the insertion hole. In a center valve type master cylinder having a valve body having a stem that is fitted into the pin member and engageable with the pin member, and a valve seat on which the valve body can be seated, a portion of the portion where the insertion hole of the piston is formed The inner gap formed between the outer diameter and the inner diameter of the annular support member is set to be larger than the outer gap formed between the inner diameter of the cylinder hole and the maximum outer diameter of the annular support member. With A part of the outer peripheral surface of the annular support member
By cutting out, the cylinder bore inner diameter and the annular support
The gap formed with the outer diameter of the holding member is locally enlarged.
Center valve type master cylinder, characterized in that the is solved by.

As described above, according to the present invention, the inner side formed between the inner diameter of the annular support member and the outer diameter of the piston is larger than the outer side gap formed between the cylinder hole and the maximum outer diameter of the annular support member. The gap is set large so as to ensure a sufficient gap as a liquid passage between the annular support member and the piston.

Here, the annular support member is supported by the abutting action with the inner wall surface of the cylinder hole by the maximum outer diameter portion of the annular support member. Therefore, in order to ensure a gap between the cylinder bore and the annular support member (i.e., the outer clearance) as part of the communication passage of the hydraulic fluid, by cutting out a part of the outer peripheral surface of the ring-shaped support member, the outer Expand the gap locally.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. In each of the embodiments described below, the case where the present invention is applied to a tandem brake master cylinder will be described.

FIG. 1 shows a primary side of a center valve type master cylinder according to a first embodiment of the present invention. Inside the cylinder hole 2 formed in the cylinder body 1, a primary piston (hereinafter, referred to as
Just use the piston. ) 3 is slidably inserted, and a primary hydraulic chamber (hereinafter, simply referred to as hydraulic chamber) 6 is defined between the piston 3 and the secondary piston 5. A guide member 7 for guiding the axial movement of the piston 3 is provided at the opening end 2a of the cylinder hole 2 with a seal ring 10.
It is attached via the C-ring 9 and is prevented from coming off by the C-ring 9. A sealing member 8 is arranged on the inner peripheral portion of the guide member 7 to block liquid communication between the inside and outside of the master cylinder.

A boss portion 11 into which a nipple portion 13 of a hydraulic fluid reservoir is fitted via a grommet seal 12 is formed on the outer peripheral portion of the cylinder body 1, and the inside of the boss portion 11 is inserted into a cylinder hole through a through hole 14. It communicates with 2. Further, the through hole 14 and the hydraulic chamber 6 are connected via a center valve mechanism V described later.

The center valve mechanism V has an elongated hole-like insertion hole 15 formed through the body of the piston 3 in the radial direction.
And a pin member 16 which is inserted into the insertion hole 15 and is movable in the axial direction of the piston 3 relative to the piston 3, a hydraulic chamber 6 formed in the axial direction of the piston 3, and the insertion hole 15
A valve body 18 having a stem 18a loosely fitted into the inner hole 17, a valve seat 19 on which the valve body 18 can be seated, and a valve body 18 And a valve spring 20 that biases the valve spring in the direction. Insertion hole 15 and inner hole 17
Together with the through hole 14, the hydraulic fluid reservoir and the hydraulic chamber 6
It constitutes a part of a communication passage that communicates between and, and the communication passage is opened or closed according to the opening and closing of the center valve mechanism V.

The axial end of the pin member 16 is connected to the piston 3
Of the annular support member 2 that covers the portion where the insertion hole 15 is formed.
Supported by 1. Therefore, in the present embodiment, as clearly shown in FIG. 2, an inner gap G1 formed between the outer diameter of the portion of the piston 3 where the insertion hole 15 is formed and the inner diameter of the annular support member 21 is An outer gap G formed between the inner diameter of the cylinder hole 2 and the maximum outer diameter of the annular support member 21.
It is set larger than 2. The maximum outer diameter portion of the annular support member 21 is slidably supported on the inner wall surface of the cylinder hole 2.

Referring to FIG. 1, when the master cylinder is not in operation, the annular support member 21 is in a position in contact with the stopper 37, so that the stem 18a of the valve body 18 is pin member 1.
6, the valve body 18 is separated from the valve seat 19, and the center valve mechanism V is opened.

As shown in FIG. 2, notches 22 are partially formed on the outer peripheral surface of the annular support member 21 (in this embodiment, four places at intervals of 90 degrees) and the inner diameter of the cylinder hole 2. A gap G2 'larger than the outer gap G2 is locally formed between them to secure a sufficient flow path for the working fluid.

With reference to FIGS. 2 to 4, the annular support member 21 in the present embodiment is made of synthetic resin, and is 2 in the circumferential direction.
The structure is divided, and a pair of arcuate members 25, 25 having the same shape and having a convex portion 23 at one end and a concave portion 24 at the other end are engaged with each other by the convex portion 23 and the concave portion 24, respectively. To be done. Each arcuate member 25 has a pin member 16
Bottomed fitting holes 26, 26 into which the ends of are fitted, are formed, and when the arc-shaped members 25 are combined, the pin member 1
6 is configured to be supported. The arc-shaped member 2
The gap S (see FIG. 3) formed in the combination portion of 5 connects the inner peripheral side and the outer peripheral side of the annular member 21.

Referring again to FIG. 1, a recess forming member 27 for supporting one end of the valve spring 20 is provided at the tip end portion of the piston 3 on the hydraulic chamber 6 side, so that the opening is formed on the hydraulic chamber 6 side. A recess 30 is formed so as to face the. A through hole 28 for guiding the axial movement of the shaft portion 18b of the valve body 18 protruding toward the hydraulic chamber 6 is formed at a portion of the recess forming member 27 corresponding to the bottom of the recess 30. The through hole 28 is formed with a notch 29 that can be a part of the flow path of the hydraulic fluid.
The through hole 28 has a function of guiding proper movement of the valve body 18 in the axial direction.

A suppressing means 31 for suppressing the flow of hydraulic fluid from the hydraulic chamber 6 side to the hydraulic fluid reservoir 13 side is housed in the recess 30. The suppressing means 31 includes a plate-shaped portion 32 that is movable in the axial direction of the piston 3 in the recess 30, and an annular protrusion that protrudes from the plate-shaped portion 32 toward the bottom of the recess 30 and can be seated on and detached from the bottom. 33, and a narrowed portion 34 formed by cutting out a part of the protruding portion 33. The throttle unit 34 has a function of changing the flow passage area in the communication passage for the hydraulic fluid between the hydraulic chamber 6 and the hydraulic fluid reservoir 13 to be small.

The movement of the suppressing means 31 toward the hydraulic chamber 6 side is restricted by the retainer 35 which supports the other end of the spring 36 whose one end is supported by the secondary piston 5. The retainer 35 is formed with a plurality of holes 35a for communicating the liquid between the recess 30 and the hydraulic chamber 6.

The present embodiment is configured as described above, and its operation will be described below.

When the master cylinder is not operating, the piston 3 is in the position shown in FIG. 1 and the center valve mechanism V is in the open state. When the driver operates the brakes,
The piston 3 moves forward to the hydraulic chamber 6 side, whereby the valve body 18
Is seated on the valve seat 19, the center valve mechanism V is closed, and the fluid communication between the hydraulic fluid reservoir 13 and the hydraulic chamber 6 is cut off. When the piston 3 further advances, brake fluid pressure is generated in the fluid pressure chamber 6, and the generated brake fluid pressure is supplied to a wheel braking device (not shown) via an output port (not shown), so that a predetermined braking action is performed.

During the brake operation, the pin member 16 is pushed by the inner wall of the insertion hole 15 and moves forward together with the piston 3,
The annular support member 21 that supports the pin member 16 moves while its maximum outer diameter portion is guided by the inner wall surface of the cylinder hole 2.

The restraining means 31 during the above-mentioned brake operation
Comes into contact with the bottom wall of the recess 30 and the hydraulic chamber 6 is formed by the throttle portion 34.
Of the hydraulic fluid from the hydraulic fluid reservoir 13 side to the hydraulic fluid reservoir 13 side, the generation of hydraulic pressure in the hydraulic chamber 6 is promoted until the center valve mechanism V is closed, and the brake pedal is initially depressed. Improves brake response in.

When the brake operation by the driver is released, the piston 3 retreats toward the non-actuated position due to the pressure in the hydraulic chamber 6 and the spring force of the spring 36. Then, the annular support member 21 first contacts the stopper 37 to be in the state shown in the figure, and then the stem 18a contacts the pin member 16 to separate the valve body 18 from the valve seat 19 and open the center valve mechanism V. To do. As a result, hydraulic fluid is supplied from the hydraulic fluid reservoir 13 side to the hydraulic chamber 6 side, and the piston 3 is retracted to the inoperative position shown. Since the suppressing means 31 moves to the hydraulic chamber 6 side due to the pressure difference, the hydraulic fluid reservoir 13
The hydraulic fluid from the is rapidly flowed into the hydraulic chamber 6 side.

Therefore, according to the present embodiment, the pin member 1
The inner gap G1 that is the gap between the inner diameter of the annular support member 21 that supports 6 and the outer diameter of the piston 3 is the outer gap G2 that is the gap between the cylinder hole 2 and the maximum outer diameter of the annular support member 21. And a larger flow passage cross section of the inner gap G1 than before, and the gap between the cylinder hole 2 and the outer diameter of the annular support member 21 is formed by the notch 22 formed on the outer peripheral surface of the annular support member 21. Since a sufficient gap G2 'is secured, the hydraulic fluid is smoothly supplied from the hydraulic fluid reservoir 13 to the hydraulic chamber 6 when the driver releases the brake operation, and the piston 3 is quickly returned to the non-operating position. Therefore, it is possible to avoid a delay in loosening the brake operation.

Further, the above master cylinder has a hydraulic fluid pressurizing means (a hydraulic pump) for generating a brake hydraulic pressure, and the hydraulic fluid suction side of the hydraulic fluid pressurizing means is connected to the hydraulic chamber 6 and the communication passage. Even when applied to a brake system connected to the hydraulic fluid reservoir 13 via the above, according to the present embodiment, the function of the system is not hindered.

That is, the above-mentioned brake system is an automatic brake system that detects the state of the vehicle based on, for example, the steering angle of the steering wheel or the lateral yaw rate of the vehicle and automatically performs appropriate brake control for each wheel. ,
A system that sucks the hydraulic fluid in the hydraulic fluid reservoir through the inside of the master cylinder, pressurizes the sucked hydraulic fluid, and supplies the pressurized hydraulic fluid to the brake device of each wheel. When the brake system is operated when the brake operation is not performed, the respective gaps between the annular support member 21 and the cylinder hole 2 and the piston 3 are secured as a sufficient flow passage area for the hydraulic fluid. It is possible to properly perform the suction action of the hydraulic fluid by the hydraulic fluid pressurizing means.

Further, according to the present embodiment, since the annular support member 21 is supported by the inner wall surface of the cylinder hole 2 in the cylinder hole 2, it is common regardless of the seal diameter of the piston 3. Since the pin member 16 can be supported by the annular support member with respect to the piston 3, this is advantageous when the requirement for the piston to have a smaller diameter is satisfied.

Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 5 shows the center valve mechanism V on the primary side of the center valve type master cylinder according to this embodiment. In this embodiment,
The configuration of the annular support member 41 that supports the axial end portion of the pin member 16 that is inserted into the insertion hole 15 of the piston 3 is slightly different from that of the first embodiment described above. Since the other configurations are similar to those of the above-described first embodiment, the corresponding parts are designated by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIGS. 6 and 7, the annular support member 41 in the present embodiment has a structure in which it is divided into two in the circumferential direction as in the case of the above-described first embodiment, and has a convex shape at one end. The pair of arcuate members 45, 45 having the same shape and provided with the portion 43 and the recess 44 at the other end are formed by engaging the projection 43 and the recess 44 with each other. Further, each arc-shaped member 45 is formed with an engagement hole 46 with which the reduced-diameter end of the pin member 16 engages, and when the both arc-shaped members 45 are combined, the pin member 16 is supported. To be configured.

Therefore, in this embodiment, the concavo-convex engaging portion P of each arc-shaped member 45 or the engaging portion Q (see FIG. 7) between the end of the pin member 16 and the engaging hole 46 is snap-engaged. By holding the pin member 16 and the arc-shaped member 45
We are trying to achieve the prevention of separation.

Further, the plurality of notches 42 partially formed on the outer peripheral surface of the annular support member 41 have an arc shape, and a gap G2 'larger than the outer gap G2 is formed to secure a sufficient flow passage area. is doing. Further, the inner gap G1 is formed to be larger than the outer gap G2 as in the first embodiment.

Also according to the present embodiment configured as described above, the same operation and effect as those of the above-described first embodiment can be obtained.

Next, a third embodiment of the present invention will be described with reference to FIGS. FIG. 8 shows the center valve mechanism V on the primary side of the center valve type master cylinder according to this embodiment. Also in the present embodiment, the configuration of the annular support member 51 that supports the axial end portion of the pin member 16 that is inserted into the insertion hole 15 of the piston 3 is different from that of the first embodiment described above. Since the other configurations are similar to those of the above-described first embodiment, the corresponding parts are designated by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIGS. 9 and 10, the annular support member 51 according to the present embodiment has a pair of arc-shaped members 55 having a large diameter portion 53 and a small diameter portion 54 at both ends of the pin member 16. After being fitted into the fitting holes 57 and assembled, a C-shaped leaf spring 56 is fitted on the outer periphery of the small diameter portion 54 of each arc-shaped member 55 to hold the pin member 16 and prevent the arc-shaped member 55 from being separated. Both have the same configuration.

Further, there are a plurality of notches 52 partially formed on the outer peripheral surface of the large diameter portion 53 of the arcuate member 55, and a gap G2 'larger than the outer gap G2 is formed to form a sufficient flow path. The area is secured. Further, the inner gap G1 is formed to be larger than the outer gap G2 as in the first embodiment.

Also according to the present embodiment configured as described above, the same operation and effect as those of the above-described first embodiment can be obtained.

Although the respective embodiments of the present invention have been described above, it goes without saying that the present invention is not limited to these embodiments.
Various modifications are possible based on the technical idea of the present invention.

For example, in each of the above-mentioned embodiments, the notch portions 22, 42, 42 are formed on the outer peripheral surface of the annular supporting members 21, 41, 51.
Although 52 is provided to secure a liquid flow path between the cutout and the inner diameter of the cylinder hole 2, the number and shape of the notches are not limited to those in the above-described embodiments.

In each of the above embodiments, the case where the present invention is applied to the primary side of the tandem type brake master cylinder is explained, while the secondary side is not particularly mentioned, but this secondary side is also the center valve type. It may be configured by or other configurations.

Further, in the above-described third embodiment, the maximum outer diameter of the annular support member 51 is set to be the outer diameter of the large diameter portion 53 of each arcuate member 55, which is shown in FIG. As described above, the outer diameter of the C-shaped leaf spring 56 fitted on the outer peripheral surface of the arc-shaped member 55 may be used. In this case, the gap G formed between the both end portions 56a, 56a of the C-shaped leaf spring 56
2 'will correspond to the gap formed by the notch 52 in the third embodiment. It should be noted that the distance between the pair of arc-shaped members 55 is such that the ends of the arc-shaped members 55 have projections 56 b formed on the inner peripheral side of the C-shaped leaf spring 56.
Maintained by engaging 6b.

[0044]

As described above, according to the center valve type master cylinder of the present invention, the hydraulic fluid is smoothly supplied from the hydraulic fluid reservoir to the hydraulic chamber when the driver releases the brake operation. The piston can be quickly returned to the non-actuated position, and it becomes possible to avoid a delay in loosening the brake operation.

Further, in addition to the center valve type master cylinder of the present invention, there is provided a hydraulic fluid pressurizing means for generating a brake hydraulic pressure, and the hydraulic fluid suction side of the hydraulic fluid pressurizing means is located in the hydraulic chamber and the communication passage. When the present invention is applied to a brake system that is connected to a hydraulic fluid reservoir via a hydraulic fluid reservoir, it is possible to properly perform a desired function of the system without inhibiting the hydraulic fluid suction action of the hydraulic fluid pressurizing means. Becomes

[Brief description of drawings]

FIG. 1 is a side sectional view showing a first embodiment of the present invention.

FIG. 2 is a sectional view taken along the line [2]-[2] in FIG.

FIG. 3 is a plan view of an arc-shaped member that constitutes the annular support member according to the first embodiment of the present invention.

FIG. 4 is a side view of the same.

FIG. 5 is a side sectional view of an essential part showing a second embodiment of the present invention.

6 is a sectional view taken along the line [6]-[6] in FIG.

FIG. 7 is a plan view of an annular support member according to a second embodiment of the present invention.

FIG. 8 is a side sectional view of an essential part showing a third embodiment of the present invention.

9 is a sectional view taken along line [9]-[9] in FIG.

FIG. 10 is a side view of an annular support member according to a third embodiment of the present invention.

FIG. 11 is a cross-sectional view showing a modification of the third embodiment of the present invention.

[Explanation of symbols]

1 cylinder body 2 cylinder holes 3 pistons 6 hydraulic chamber 13 Nipple of hydraulic fluid reservoir 15 insertion holes 16 pin member 17 inner hole 18 valve body 18a stem 19 seat 21 annular support member 22 Notch 23 Convex part 24 recess 25 Arc member 30 recess 31 Control means 32 Plate 33 Projection 34 Throttle 41 annular support member 42 Notch 43 convex 44 recess 45 Arc member 51 annular support member 52 Notch 55 Arc member 56 C type leaf spring G1 inner gap G2 outside gap V center valve mechanism

Continuation of the front page (56) Reference JP-A-11-115723 (JP, A) JP-A-10-67314 (JP, A) JP-A-10-53120 (JP, A) JP-A-7-17386 (JP , A) JP-A-7-17385 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B60T 11 / 00-11 / 34

Claims (6)

(57) [Claims] 1. A cylinder body having a cylinder hole, a piston slidably inserted into the cylinder hole to define a hydraulic chamber on one end side, and provided between the hydraulic chamber and a hydraulic fluid reservoir. A center valve mechanism that is disposed in the communication passage and connects or disconnects the communication passage. The center valve mechanism is formed so as to penetrate in the radial direction of the piston and is a part of the communication passage. A hole, a pin member that is inserted into the insertion hole and is movable in the axial direction of the piston relative to the piston, and a portion that supports the axial end portion of the pin member and forms the insertion hole of the piston. A ring-shaped support member that fits in the valve body, a valve body that has a stem that is fitted in an inner hole that is formed in the axial direction of the piston and that communicates the hydraulic chamber with the insertion hole, and that has a stem that is engageable with the pin member, and this valve Body wear In a center valve type master cylinder having a possible valve seat, an inner gap formed between an outer diameter of a portion of the piston where the insertion hole is formed and an inner diameter of the annular support member is the cylinder. the hole inside diameter, with is set to be larger than the outer gap formed between the maximum outer diameter of the annular support member, cut a part of the outer peripheral surface of the annular support member
Due to the lack, the cylinder hole inner diameter and the annular support portion
A center valve type master cylinder characterized in that the gap formed between the outer diameter of the material and the material is locally enlarged . 2. The annular support member is divided in the circumferential direction.
The structure has a convex portion at one end and a concave portion at the other end.
The center valve type master cylinder according to claim 1, wherein the arcuate members are engaged with each other in a concavo-convex manner . 3. The end portion of the piston on the hydraulic chamber side is
A recess is formed with the opening facing the hydraulic chamber,
The flow of hydraulic fluid from the hydraulic chamber side to the hydraulic fluid reservoir side
When it occurs, the restraint means to restrain the flow is in the recess.
The center valve type master cylinder according to claim 1 or 2, which is housed . 4. The suppressing means is provided in the communication passage.
The center valve type master cylinder according to claim 3 , wherein the center valve type master cylinder has a throttle portion that changes a flow passage area to a small extent. 5. The restraint means is in the axial direction of the piston.
Provided so as to be movable toward at least the bottom side of the recess.
A plate-like protrusion that can be attached to and detached from the bottom of the recess
A member, wherein the narrowed portion is a cutout formed in the protruding portion.
The center valve type master cylinder according to claim 3 or 4, which is provided by a valve. 6. The center valve type master cylinder
Separately, it has a hydraulic fluid pressurizing means for generating brake fluid pressure.
The hydraulic fluid suction side of the hydraulic fluid pressurizing means of the
A brake connected to the hydraulic fluid reservoir via a communication passage.
Any of claims 1 to 5 applied to the system
Center valve type master cylinder according to any Re.