JP3706724B2 - Center valve device for master cylinder - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a center valve device of a master cylinder mainly used for an anti-lock brake of an automobile, and in particular, a piston that fits into a cylinder hole of a cylinder body to define a hydraulic chamber, a valve seat that faces the hydraulic chamber, A relief port that connects the hydraulic chamber to the reservoir through the valve seat is formed, and a poppet valve that opens and closes the relief port in cooperation with the valve seat is connected to a valve rod that is loosely inserted into the relief port, and one end of the valve rod. a valve head facing the valve seat is formed, the umbrella portion, filling the annular recess formed in the valve seat-side end face, while composed of a rubber sealing member is vulcanized bonded to the sealing member An annular seal lip that can be raised from its end face and seated on the valve seat is formed, and this poppet valve is closed at the piston retracted position and closed as the piston moves forward. Those that have been connected means ゝ an improvement.
[0002]
[Prior art]
Such a center valve device for a master cylinder is already known as disclosed in, for example, Japanese Patent Laid-Open No. 4-50915.
[0003]
[Problems to be solved by the invention]
In a master cylinder equipped with such a center valve device, kickback pressure is transmitted to the hydraulic chamber during brake anti-lock control, particularly during pressure reduction control, and accordingly, a high oil pressure radially inward is applied to the seal lip. However, in the center valve device disclosed in the above publication, the outer end surface of the poppet valve seal member on which the seal lip bulges is a flat surface. When pushed in the direction, there is a concern that a large tensile force acts on the outer end surface of the seal member on the outer peripheral side of the seal lip, and the seal member is peeled off from the inner peripheral surface of the annular recess of the umbrella portion.
[0004]
The present invention has been made in view of such a point, and even when the anti-lock control of the brake is performed, even if the seal lip is pushed inward in the radial direction by a high hydraulic pressure by kickback, the seal member and the seal member are vulcanized and joined. can be easily prevented from delamination between the poppet valve head portion has for its object to provide a center valve device of the master cylinder.
[0005]
[Means for Solving the Problems]
To achieve the above object, according to the present invention, a piston that fits into a cylinder hole of a cylinder body to define a hydraulic chamber, a valve seat that faces the hydraulic chamber, and the hydraulic chamber communicates with a reservoir through the valve seat. A poppet valve that forms a relief port and opens and closes the relief port in cooperation with the valve seat, a valve rod that is loosely inserted into the relief port, and an umbrella portion that is formed at one end of the valve rod and faces the valve seat , seating of the umbrella portion, filling the annular recess formed in the valve seat-side end face, while composed of a rubber sealing member is vulcanized bonded to the sealing member, the valve seat and raised from the end face an annular sealing lip is formed which may, in this poppet valve, opens it in the retracted position of the piston, with the advance of the piston linked closing operation means for closing this, in the center valve device of the master cylinder , seal When the outer peripheral surface receives high hydraulic pressure on the outer peripheral surface and is pushed inward in the radial direction, the tensile force acting on the outer end surface of the seal lip outer peripheral side of the seal member causes the outer peripheral surface of the seal member and the inner peripheral surface of the annular recess of the umbrella portion to prevent to separate the door, the end face of the sealing member and that forms an annular groove surrounding the sealing lip and can absorb or alleviate the tensile force to the first feature.
[0006]
According to this first feature, during braking with the seal lip of the poppet valve seated on the valve seat of the piston, the kickback pressure accompanying the operation of the antilock control device returns to the hydraulic chamber, and the hydraulic chamber When the pressure is greatly increased, the seal lip receives a high hydraulic pressure on the outer peripheral surface and is pushed radially inward, so that a tensile force acts on the outer end surface of the seal lip on the outer peripheral side of the seal lip. Absorbed or relaxed by the annular groove on the end surface of the seal member surrounding the base of the lip, it is possible to prevent peeling of the outer peripheral surface of the seal member due to the tensile force and the inner peripheral surface of the annular recess of the umbrella portion to which this is vulcanized. .
[0007]
In addition to the above feature, the present invention has a second feature that the valve seat is formed in a conical shape that is inclined downward in the radial direction.
[0008]
According to the second feature, even when the seal lip is seated on the valve seat, even if the seal lip is pushed inward in the radial direction by the high hydraulic pressure as described above, the seal lip is displaced inward in the radial direction by the valve seat. As a result, the normal seating state of the seal lip with respect to the valve seat can be maintained, and the tensile force acting on the end face of the seal member on the outer peripheral side of the seal lip is mitigated. Combined with the action, it is possible to more reliably prevent peeling between the outer peripheral surface of the seal member and the inner peripheral surface of the annular recess of the umbrella portion.
[0009]
According to the present invention, in addition to the above features, the umbrella portion is provided with a circular recess opening on the end surface opposite to the valve rod, and a plurality of anchor holes communicating between the circular recess and the annular recess. The circular recesses, the annular recesses, and the anchor holes are filled with an elastic body made of rubber and vulcanized and bonded, and the seal member is constituted by a portion of the elastic body that is filled and vulcanized and bonded to the annular recess. This is the third feature.
[0010]
Embodiment
Embodiments of the present invention will be described below based on examples of the present invention shown in the accompanying drawings.
[0011]
1 is a longitudinal side view of the master cylinder, FIG. 2 is an enlarged view around the front center valve device of FIG. 1, FIG. 3 is an enlarged view of 3 parts of FIG. 2, and FIG. 4 is a sectional view taken along line 4-4 of FIG. FIG. 5 is an operation explanatory diagram corresponding to FIG.
[0012]
First, in FIG. 1, M denotes a tandem master cylinder for a two-system antilock brake of an automobile, and a front piston 2f and a rear piston 2r are fitted in series in a cylinder hole 1a of the cylinder body 1. A front hydraulic chamber 3f is defined between the front piston 2f and the front end wall of the cylinder hole 1a, and a rear hydraulic chamber 3r is defined between the pistons 2f and 2r. Two brake hydraulic circuits are connected to the output ports 4f and 4r of the hydraulic chambers 3f and 3r.
[0013]
The rear piston 2r has a piston rod 2b that is slidably supported by a bearing 9 fitted to the rear end of the cylinder hole 1a. The piston rod 2b has a negative pressure that is actuated by a brake pedal. The output 杆 R of the booster is connected.
[0014]
Each piston 2f, 2r is provided with a cup seal 5f, 5r that is in close contact with the cylinder hole 1a, respectively, and each intermediate part has a small diameter so as to define the front and rear replenishing oil chambers 6f, 6r in the cylinder hole 1a. It has become. Then, oil holes 7f and 7r for communicating these replenishing oil chambers 6f and 6r with the back surfaces of the cup seals 5f and 5r are formed in the pistons 2f and 2r.
The front hydraulic chamber 3f has a front return spring 8f for urging the front piston 2f in the backward direction, and a rear return spring 8r for urging the rear piston 2r in the backward direction between the pistons 2f and 2r. It is reduced.
[0015]
A pair of front and rear inlet cylinders 25f and 25r communicating with the front replenishing oil chamber 6f and the rear replenishing oil chamber 6r through a pair of front and rear supply ports 12 and 12 are formed on the upper portion of the cylinder body 1, respectively. A pair of front and rear outlet tubes 26f and 26r projecting from the bottom wall of the reservoir 10 are fitted through seal members 27 and 27, respectively, and connecting bosses projecting from the opposing surfaces of the cylinder body 1 and the reservoir 10, respectively. 28 and 29 are connected by a bolt 30. Thus, the reservoir 10 is coupled to the master cylinder M.
[0016]
The interior of the reservoir 10 is partitioned into a front oil chamber 10f and a rear oil chamber 10r by a partition wall 11 standing at a certain height from the bottom wall. Accordingly, the front oil chamber 10f and the rear oil chamber 10r communicate with the front supply oil chamber 6f and the rear supply oil chamber 6r, respectively. In the reservoir 10, the hydraulic oil is normally stored up to a level above the upper end of the partition wall 11.
[0017]
The front replenishing oil chamber 6f includes a long hole 13f that crosses the middle part of the front piston 2f, and a relief port 14f that opens from the long hole 13f to the front end surface through the center of the front piston 2f. Via the front hydraulic chamber 3f. The long hole 13f is provided with a long diameter longer than the sliding stroke of the front piston 2f in the axial direction of the piston 2f.
[0018]
2 and 3, a front center valve device Vf is provided in the front piston 2f to open and close the relief port 14f of the front piston 2f. The front center valve device Vf includes a valve seat 20, a valve housing 15, a poppet valve 16, a valve spring 17, and a valve opening rod 18.
[0019]
The valve seat 20 is formed on the front end surface of the front piston 2f with the relief port 14f as the center, and has a conical shape with a downward gradient in the radial direction.
[0020]
The valve opening rod 18 passes through the long hole 13f of the front piston 2f, and is supported by the cylinder body 1 at both ends.
[0021]
The valve housing 15 has a cup shape having a through-hole 19 in the peripheral wall, and is fitted to the front end portion of the front piston 2 f and is locked by a locking ring 21.
[0022]
The poppet valve 16 includes a valve rod 31 that slidably passes through the relief port 14f, and an umbrella portion 32 that is integrally formed at one end thereof and faces the valve seat 20. A plurality of strips of axial grooves 31a (see FIG. 4) for providing the relief port 14f in a conductive state are provided. The valve stem 31 and the umbrella part 32 are made of metal.
[0023]
The umbrella portion 32 has an annular recess 32a opened on the end surface on the valve rod 31 side, a circular recess 32b opened on the opposite end surface, and a plurality of anchor holes 32c communicating between the annular recess 32a and the circular recess 32b. These are filled with an elastic body 33 made of rubber and vulcanized and joined. A seal member 34 is constituted by a portion of the elastic body 33 that is filled in and joined to the annular recess 32a, and an annular seal lip 34a that can be seated on the valve seat 20 projects integrally with the outer end surface of the seal member 34. An annular groove 35 that surrounds the base of the seal lip 34a is formed.
[0024]
The end of the elastic body 33 opposite to the seal lip 34 a has a stepped shape and protrudes from the end surface of the umbrella portion 32, and the valve spring 17 is interposed between the stepped protruding portion and the front end wall of the valve housing 15. The poppet valve 16 is urged to seat the seal lip 34a on the valve seat 20 by the spring force.
[0025]
Thus, the valve opening rod 18 and the valve spring 17 constitute an opening / closing operation means A for opening and closing the poppet valve 16.
[0026]
In FIG. 1 again, the rear replenishing oil chamber 6r includes a long hole 13r that crosses the middle part of the rear piston 2r, and a relief port 14r that opens from the long hole 13r to the front end surface through the center of the rear piston 2r. And communicates with the rear hydraulic chamber 3r. The long hole 13r has a longer diameter shorter than the long hole 13f of the front piston 2f.
[0027]
A rear center valve device Vf is provided in the rear piston 2r to open and close the relief port 14r of the rear piston 2r. In the rear center valve device Vr, both ends of the valve opening rod 18 penetrating the long hole 13r are supported by stopper rings 37 slidably fitted to the piston rod 2b of the rear piston 2f immediately before the bearing 9. Since the configuration is the same as that of the front center valve device Vf, the description of the configuration is omitted.
[0028]
The stopper ring 37 is in contact with the front end of the bearing 9 so as to define the retracted position of the rear piston 2f.
[0029]
A guide shaft 38 having an enormous head 38a at the front end projects from the front surface of the valve housing 15 of the rear center valve device Vr, and a retainer 39 that receives the rear end of the front piston 2f is slidably fitted thereto. Then, the rear return spring 8r is contracted between the retainer 39 and the rear piston 2f. The set load of the rear return spring 8r is set larger than that of the front return spring 8f. Therefore, when the rear piston 2f occupies the retracted position, the retainer 39 is pressed against the contact position with the head portion 38a of the guide shaft 38 by the spring force of the rear return spring 8r. The front piston 2f that retreats with spring force is received and its retreat position is defined. A recess 40 that can receive the head 38a of the guide shaft 38 is provided on the rear end surface of the front piston 2f.
[0030]
Next, the operation of this embodiment will be described.
[0031]
If the front piston 2f and the rear piston 2f occupy the respective retreated positions, the valve opening rod 18 receives the valve rod 16b of the poppet valve 16 and opens the valve 16 in each center valve device Vf, Vr. Hold in position.
[0032]
When the negative pressure booster is operated from such a state and the rear piston 2r is advanced by the output rod R, first, the front piston 2f is advanced through the rear return spring 8r to compress the front return spring 8f. To do.
[0033]
Thus, according to the forward movement of the front piston 2f, first, in the front center valve device Vf, the poppet valve 16 is separated from the valve opening rod 18, and at the same time the valve member 17 seats the seal member 34 by the force of the valve spring 17. Since the relief port 14f is closed (see FIG. 5), hydraulic pressure is generated in the front hydraulic chamber 3f as the front piston 2f continues to advance, and the hydraulic pressure is supplied to the corresponding wheel brake from the output port 4f. Is done.
[0034]
When the hydraulic pressure is generated in the front hydraulic chamber 3f, the rear return spring 8r starts to be compressed as the rear piston 2r moves forward. Then, first, in the rear center valve device Vr, the poppet valve 26 becomes free from the stopper ring 37 and the valve opening rod 18, and the valve spring 27 is closed, so that the seal member 41 is seated on the valve seat 21. To close the relief port 14r. When the rear center valve device Vr is closed in this way, hydraulic pressure is generated in the rear hydraulic chamber 3r by the subsequent advance of the rear piston 2r, and this hydraulic pressure is supplied to the corresponding wheel brake from the output port 4r. During this time, the head 38a of the guide shaft 38 is received in the recess 40 at the rear end of the front piston 2f, and thus does not prevent the rear piston 2r from moving forward.
[0035]
By the way, during such braking, when an anti-lock control device (not shown) is operated, a high kickback pressure is returned to the front and rear hydraulic chambers 3f and 3r, and when these hydraulic chambers are greatly increased, each center valve device Vf, At Vr, the seal lip 34a of the seal member 34 seated on the valve seat 20 receives high oil pressure on the outer peripheral surface and is pushed inward in the radial direction, and accordingly, the seal member 34 on the outer peripheral side of the seal lip 34a. A tensile force acts on the outer end surface, but since the annular groove 35 surrounding the seal lip 34a is formed on the outer end surface, the tensile force is absorbed or relaxed by the annular groove 35, and is caused by the tensile force. The separation between the outer peripheral surface of the seal member 34 and the inner peripheral surface of the annular recess 32a of the umbrella portion 32 can be prevented, and the durability of the seal member 34 can be ensured.
[0036]
In addition, at that time, the valve seat 20 on which the seal lip 34a is seated is formed in a conical shape having a downward slope toward the outer side in the radial direction. Inward displacement can be suppressed, and as a result, a normal seating state of the seal lip 34a with respect to the valve seat 20 can be maintained, and a tensile force acts on the outer end surface of the seal member 34 on the outer peripheral side of the seal lip 34a. In combination with the action of the annular groove 35, the separation between the outer peripheral surface of the seal member 34 and the inner peripheral surface of the annular recess 32a of the umbrella portion 32 can be prevented more reliably.
[0037]
Next, when the output rod R of the negative pressure booster is retracted, both pistons 2f, 2r are returned to the predetermined retracted position by the force of the return springs 8f, 8r, and the hydraulic chambers 3f, 3r are depressurized in the retracting process. For example, the outer periphery of the cup seals 5f and 5r bends forward due to the pressure difference between the cup seals 5f and 5r to create a gap between the inner surface of the cylinder hole 1a and replenish through the gap and the oil holes 7f and 7r of the pistons 2f and 2r. The hydraulic oil is supplied from the oil chambers 6f and 6r to the hydraulic chambers 3f and 3r. If the hydraulic oil is excessively replenished at that time, when the pistons 2f and 2r return to the retreating limit, the excess oil is supplied to the replenishing oil chambers 6f and 6r through the relief ports 14f and 14r opened by the poppet valves 16 and 26. Returned to
[0038]
The present invention is not limited to the above embodiments, and various design changes can be made without departing from the scope of the invention. For example, the present invention can be applied to a single master cylinder. Further, the reservoir 10 can be arranged separately from the master cylinder M, and the inlet cylinders 25f and 25r and the outlet cylinders 26f and 26r can be communicated with each other via conduits.
[0039]
【The invention's effect】
According to a first aspect of the present invention as described above, the valve head of the poppet valve to open and close the relief port in cooperation with a valve seat facing the oil chamber, the annular recess formed in the valve seat-side end surface filling rubber seal member, in the center valve device master cylinder which is vulcanized bonding, sealing lip of the seal member of the seal member by being pushed radially inwardly by receiving a high pressure on the outer peripheral surface, the seal for tensile force acting on the outer end surface of the lip outer peripheral side is prevented from causing peel the annular concave inner circumferential surface of the seal member outer peripheral surface and the umbrella portion, the end face of the sealing member, the tensile force surrounds the sealing lip Since the annular groove that can be absorbed or relaxed is formed, when the kickback pressure accompanying the operation of the antilock control device returns to the hydraulic chamber during braking and the hydraulic chamber is greatly increased in pressure, the seal lip becomes higher in the hydraulic chamber. Hydraulic Be pushed radially inward, in with a sealing member end face resulting tension it is absorbed or alleviated by the annular groove surrounding the sealing lip, the tensile force by the sealing member and which is vulcanized bonded poppet valve Separation from the umbrella portion can be prevented, and the durability of the seal member can be improved.
[0040]
Further, according to the second feature of the present invention, the valve seat is formed in a conical shape that is inclined downward in the radial direction, so that when the seal lip is seated on the valve seat, the valve seat has a radius of the seal lip. It is possible to suppress the inward displacement in the direction, maintain a normal seating state of the seal lip with respect to the valve seat, and, in combination with the action of the annular groove, further peel off the sealing member from the umbrella portion. It can be surely prevented.
[Brief description of the drawings]
FIG. 1 is a vertical side view of a master cylinder embodying the present invention.
FIG. 2 is an enlarged view around the front center valve device of FIG. 1;
FIG. 3 is an enlarged view of part 3 of FIG.
4 is a cross-sectional view taken along line 4-4 of FIG.
FIG. 5 is an operation explanatory diagram corresponding to FIG. 3;
[Explanation of symbols]
A ··· Opening / closing operation means M ··· Master cylinders Vf, Vr ··· Center valve device 1 ··· Cylinder body 1a · · · Cylinder holes 2f, 2r ··· Piston 10... Reservoir 14 f, 14 r... Relief port 16... Poppet valve 20... Valve seat 31. ..Annular recess
32b ... Circular recess
32c ... Anchor hole
33... Elastic body 34... Seal member 34 a... Seal lip 35.

Claims (3)

A valve seat (20) facing the hydraulic chamber (3f, 3r), a piston (2f, 2r) that fits into the cylinder hole (1a) of the cylinder body (1) and defines the hydraulic chamber (3f, 3r); The relief chambers (14f, 14r) for communicating the hydraulic chambers (3f, 3r) with the reservoir (10) through the valve seat (20) are formed, and in cooperation with the valve seat (20), the relief ports (14f, 14r, The poppet valve (16) that opens and closes 14r) is formed at one end of the valve rod (31) that is loosely inserted into the relief port (14f, 14r) and faces the valve seat (20). configuration umbrella portion (32), the umbrella portion (32), filling the valve seat (20) side end surface formed in an annular recess (32a), because the rubber seal member is vulcanized junction (34) And the seal member (34) is raised from its end face. To form an annular sealing lip that can be seated on the seat (20) (34a), a poppet valve (16), a piston (2f, 2r) opens it in the retracted position of the piston of the (2f, 2r) In the center valve device of the master cylinder, which is connected to the opening / closing operation means (A) for closing the valve as it advances,
When the seal lip (34a) receives high oil pressure on the outer peripheral surface and is pushed radially inward, the tensile force acting on the outer end surface of the seal lip (34a) on the outer peripheral side of the seal member (34) is increased. ) in order to prevent to peel the annular recess (32a) inner peripheral surface of the outer peripheral surface and the valve head (32), the end face of the sealing member (34), surrounding the sealing lip (34a) absorbs the pulling force Alternatively , the center valve device of the master cylinder is characterized in that an annular groove (35) that can be relaxed is formed. In claim 1,
A center valve device for a master cylinder, characterized in that the valve seat (20) is formed in a conical shape having a downward gradient in the radially outward direction. In claim 1 or 2,
The umbrella portion (32) has a circular recess (32b) opened on the end surface opposite to the valve rod (31), and a plurality of anchor holes communicating between the circular recess (32b) and the annular recess (32a). (32c) is provided, and the circular recess (32b), the annular recess (32a) and the anchor holes (32c) are filled with an elastic body (33) made of rubber and vulcanized and joined. 33) A center valve device for a master cylinder, wherein the sealing member (34) is formed by a portion of 33) filled and vulcanized and joined into the annular recess (32a).

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