JP3796939B2 - Brake master cylinder valve structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a valve structure of a master cylinder used for a vehicle brake or the like.
[0002]
[Prior art]
As a conventional master cylinder valve structure, for example, there is one described in JP-A-9-150728.
[0003]
This valve is a tandem type and has a center valve that communicates and shuts off the hydraulic chamber in the cylinder body and the external hydraulic fluid reservoir, and the taper contact portion of the valve rod of the center valve is on the inside and outside. It abuts against a double-structured annular member and blocks it. The outer member is made of a rubber material, and the harder inner member holds the member from the inner side.
[0004]
[Problems to be solved by the invention]
By the way, in vehicle dynamic control or the like, there is a case where control is performed so as to improve the turning performance by applying a brake to the inner ring side during turning. Therefore, the hydraulic pressure is applied even if the brake pedal is not depressed. At this time, when ABS (anti-lock brake system) is operated, pressure reduction control is performed, and the hydraulic pressure returns to the hydraulic pressure chamber in the cylinder body. Therefore, the center valve opens and closes under high pressure, the center valve is closed while the outer member of the rubber material is deformed, and the deformed outer member is engaged with the valve rod and the inner member for centering, Risk of damage.
[0005]
In order to prevent damage due to the biting of the outer member, it is only necessary to enlarge the contact portion of the valve rod and secure a deformation allowance of the outer member, but there is a possibility that the entire master cylinder is enlarged. Therefore, it has been difficult to achieve both the securing of the deformation allowance of the outer member for sealing and the biting prevention structure in a small space for accommodating the center valve.
[0006]
Therefore, an object of the present invention is to provide a structure capable of ensuring a deformation allowance and preventing damage of a seal member while evenly contacting a valve rod of a center valve.
[0007]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the invention according to claim 1 includes a cylinder body having a hydraulic chamber whose pressure is increased as the piston accommodated therein moves, and the piston has an end portion facing the hydraulic chamber. And a communication passage that communicates the hydraulic chamber with the hydraulic fluid reservoir via a valve provided in the recess and extending in the axial direction , and the valve moves the communication passage when the piston moves. In the brake master cylinder that shuts off and communicates with each other when the valve is restored, the valve is composed of a head and a rod portion, and receives a biasing force of a spring member to be biased inward in the axial direction of the recess, and the outer member and the inner member concentric annular arranged is positioned in a recess provided in the head portion of the valve rod and a said outer member and inner member abutment portion abutting, Contact side tip portion provided axially outwardly of the Kisotogawa member, from the end of the axially outside of the inner member is formed with a predetermined amount of protrusion toward the outside in the axial direction of the recess, the outer member is easily The inner member is formed to be harder than the outer member, and the abutting portion includes a first abutting portion for sealing that abuts on the abutting- side tip portion of the outer member; A second abutting portion for centering that abuts against the inner member, and the second abutting portion abuts against the inner member after the first abutting portion abuts against the outer member, A taper angle facing the outer member of the first contact portion is set to be larger than a taper angle facing the inner member of the second contact portion, and the first contact portion and the second contact portion A stepped recess is formed in between, and the abutting side front end abuts on the first abutting portion and is radially inward. This deformation when deformed and characterized by being configured to regulate by said recess.
[0008]
The invention according to claim 2 is the valve structure of the brake master cylinder according to claim 1, wherein the first contact portion is formed in a tapered shape.
[0009]
The invention according to claim 3 is the valve structure of the brake master cylinder according to claim 1 or 2, wherein the second contact portion is formed in a convex curved surface.
[0010]
A fourth aspect of the present invention is the brake master cylinder valve structure according to any one of the first to third aspects, wherein the first contact portion and the second contact portion are stepped. It is characterized by.
[0011]
Invention of Claim 5 is the valve structure of the brake master cylinder in any one of Claims 1-4, Comprising: The said outer member is formed with a rubber material, The said inner member is more than an outer member. It is characterized by being formed of a hard material such as resin or metal having high hardness.
[0012]
【The invention's effect】
According to the first aspect of the present invention, a clearance space is provided between the first abutting portion having a larger opposing angle and the second abutting portion having a smaller opposing angle, so that the abutting of the softer outer member is performed. Since it becomes possible to accept the deformation part at the time and to restrict the deformation, the deformation allowance of the outer member can be secured, and the deformation part is caught between the valve rod and the hard inner member. It can be prevented from being damaged.
[0013]
According to the second aspect of the invention, the same effect as that of the first aspect of the invention can be obtained, and uniform contact with the soft outer member can be obtained by forming the first contact portion in a tapered shape. It is done.
[0014]
According to the third aspect of the invention, the same effect as that of the first or second aspect of the invention can be obtained, and the centering property of the valve rod can be improved by forming the second contact portion on the convex curved surface. Contact can be obtained.
[0015]
According to the invention described in claim 4, the same effect as that of any one of the inventions of claims 1 to 3 can be obtained, and the first and second contact portions are different in both contact portions due to the opposing angle difference. By forming a stepped shape having a recess in the middle, the deformation of the outer member can be regulated by the stepped portion between the first and second contact portions, and the biting of the outer member can be more reliably performed. Can be suppressed.
[0016]
According to the fifth aspect of the invention, the same effect as in any of the first to fourth aspects of the invention can be obtained, and an appropriate sealing performance can be obtained by the outer member made of a rubber material. Thus, a centering function can be obtained more accurately, and the shape of the outer member can be maintained and an appropriate deformation margin can be obtained.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is an overall cross-sectional view of a tandem brake master cylinder provided with a center valve (valve) according to this embodiment. 2 is an enlarged cross-sectional view of the center valve portion of FIG. FIG. 3 is an enlarged cross-sectional view of FIG.
[0018]
A brake master cylinder 1 shown in FIG. 1 includes a primary piston 5 on the right side of the cylinder body 3, a secondary piston 9 containing a center valve 7 on the left side, and a hydraulic fluid above the cylinder body 3. A reservoir 11 is provided. The primary piston 5 is for one of the two brakes, and the secondary piston 9 is for the other brake. A push rod (not shown) is disposed in the recess 12 at the right end of the primary piston 5.
[0019]
The left end 3a of the cylinder body 3 is closed, and the primary piston 5 is prevented from coming off by a retaining ring 15 at the right end. The cylinder body 3 is sealed by a seal 17 a provided at the right end (outer end) of the primary piston 5.
[0020]
The secondary piston 9 is pressed rightward by a secondary piston return spring 19 disposed between the left end 3 a of the cylinder body 3 and a primary piston return spring 21 between the secondary piston 9 and the primary piston 5. Separated from 5.
[0021]
The seal 17b attached to the inner end of the primary piston 5 and the seals 23a and 23a attached to both ends of the secondary piston 9 allow liquid to flow between the pistons 5 and 9 and to the left of the secondary piston 9, respectively. Pressure chambers 25 and 27 are formed. The hydraulic chambers 25 and 27 are communicated with and blocked from the reservoir 11 by the valve 29 (relief port) on the primary piston 5 side and the center valve 7 built in the secondary piston 9, respectively.
[0022]
As shown in FIGS. 1 and 2, the center valve 7 is provided in a recess 13 formed in the secondary piston 9 so as to face the hydraulic chamber 27. A concentric ring-shaped outer seal (outer member) 31 and an inner retainer (inner member) 33 are disposed on the bottom 13a of the recess 13, and the recess 31a and the protrusion 33a are engaged with each other. (See FIG. 3), and integrated with each other, and is retained by a retaining ring 37 via a collar 35 with an inner collar.
[0023]
The bottom 13a of the recess 13 communicates with the reservoir 11 through the axial hole 9a, the laterally long hole 9b, the outer communication passage 9c and the port 3b of the secondary piston 9. A valve rod 41 is disposed through the retainer 33 and the shaft hole 9a.
[0024]
The outer seal 31 is made of a rubber material, and the contact-side tip 31b of the seal 31 is formed so that the inner diameter portion protrudes in the axial direction as shown in FIG. 3, and more than the end 33b of the retainer 33. A predetermined amount protrudes toward the valve rod 41 side. The retainer 33 is harder than the seal 31 and is made of a hard material such as plastic or metal having a high rigidity. The retainer 33 is substantially L-shaped, holds the shape of the seal 31 from the inner diameter side, and the flange portion 33c backs up the seal 31. is doing.
[0025]
On the other hand, the valve rod 41 comprises a head portion 43 and a rod portion 45. The head portion 43 is urged toward the seal 31 by a conical coil spring 47 disposed between the collar 35 and the inner collar portion. (See FIG. 2).
[0026]
As shown in FIG. 3, a taper contact portion (first contact portion) 43a having a predetermined taper angle is formed in the large diameter portion on the side of the head 43 facing the seal 31, and the taper contact portion 43a. Faces the tip 31b of the seal 31. The taper contact portion 43a is pressed by the coil spring 47 and contacts the tip portion 31b of the seal 31 to deform the tip portion 31b. A spherical contact portion (second contact portion) 43b having a convex shape is formed in a smaller diameter portion than the taper contact portion 43a of the head 43, and the spherical contact portion 43b faces the end portion 33b of the retainer 33. ing.
[0027]
The angle of the taper contact portion 43a facing the seal 31 (in the embodiment, the taper angle) is the angle of the spherical contact portion 43b facing the retainer 33 (in the embodiment, the taper angle when the spherical contact portion 43b is approximated to a taper). The contact portions 43a and 43b are formed in a stepped shape having a recess 43c in the middle thereof.
[0028]
The contact timing of the contact portions 43a and 43b of the valve rod 41 is such that when the taper contact portion 43a first contacts the seal 31 and the tip end portion 31b is deformed by a predetermined amount, the spherical contact portion 43b It is set so that the movement of the valve rod 41 in the abutting direction is completed by abutting on the end 33b of the retainer 33.
[0029]
The small diameter side of the spherical abutting portion 43b ends at a portion having a smaller diameter than the contact point with the retainer 33, and the rod portion 45 has a taper portion 45b having a small taper angle connected to the end portion, and the retainer 33. And a shaft portion 45c having a predetermined clearance.
[0030]
When the valve rod 41 is in contact (when the center valve 7 is closed), the distance A between the inner diameter end of the seal tip 31b and the contact inner diameter end of the retainer 33 is, for example, as in the conventional structure. The contact portion is greatly enlarged as compared with the case where the contact portion is not stepped, and the effect of the recess 43c is added to the contact portion, and the contact portion is surrounded by the tip portion 31b of the seal 31, the recess portion 43c of the valve rod 41, and the end portion 33b of the retainer 33. The space 49 (FIG. 3) is formed with a sufficient size.
[0031]
The stopper bolt 51 (see FIG. 2) is attached to a predetermined position of the cylinder body 3 in the direction perpendicular to the axis, and passes through the horizontally elongated hole 9b of the secondary piston 9. The secondary piston 9 is movable by the horizontally long hole 9b. When the brake master cylinder 1 is not operated, the tip 45 a of the rod portion 45 of the valve rod 41 contacts the stopper bolt 51. The taper contact portion 43a and the spherical contact portion 43b of the valve rod 41 are separated from the seal 31 and the retainer 33 by a predetermined amount depending on the position occupied by the secondary piston 9 when not operating (the position shown in FIGS. 1 and 2). The center valve 7 is opened, and the hydraulic chamber 27 communicates with the reservoir 11.
[0032]
Next, the operation of the center valve 7 and the brake master cylinder 1 will be described.
[0033]
In the non-operating state of the brake master cylinder 1, the pistons 5 and 9 are in the positions shown in FIG. 1, and the valve 29 and the center valve 7 are in an open state.
[0034]
When the push rod pushes the primary piston 5 to the left according to the brake operation, the valve 29 is closed as the primary piston 5 moves, and a hydraulic pressure corresponding to the pressing force is generated in the hydraulic pressure chamber 25. Due to the generated hydraulic pressure, the secondary piston 9 moves to the left, and the taper contact portion 43a and the spherical contact portion 43b of the valve rod 41 urged by the conical coil spring 47 are in this order in the seal 31 and the retainer. The center valve 7 is closed in contact with the valve 33 and hydraulic pressure is generated in the hydraulic chamber 27. The hydraulic pressures in the hydraulic chambers 25 and 27 are sent to the brakes of the respective systems from the hydraulic pressure outlets (not shown).
[0035]
The movement of the valve rod 41 in the contact direction ends when the spherical contact portion 43 b contacts the end portion 33 b of the retainer 33. At the end of the contact (when the center valve 7 is closed), the space 49 is set large, so that the deformation of the distal end portion 31b of the seal 31 is sufficiently absorbed and the deformation is restricted. The possibility that 31b is caught between the valve rod 41 and the retainer 33 and damaged is eliminated.
[0036]
Further, due to the centering action of the spherical abutting portion 43b, the abutting portions 43a and 43b of the valve rod 41 abut against the seal 31 and the retainer 33, respectively, thereby improving the sealing performance and preventing damage to the distal end portion 31b of the seal 31. An effect is obtained.
[0037]
When the brake operation is released, the pistons 9 and 5 are returned to their original positions by the high hydraulic pressure and the return springs 19 and 21, and the valve 29 and the center valve 7 are opened accordingly.
[0038]
Even if the center valve is closed while the distal end portion 31 b of the seal 31 is deformed, the distal end portion 31 b is not caught by the valve rod 41 and the retainer 33.
[0039]
Thus, according to the present embodiment, a large space 49 is provided by providing the taper contact portion 43a, the spherical contact portion 43b, and the concave portion 43c of a predetermined size on the head portion 43 of the valve rod 41. As a result, the deformation allowance of the seal 31 can be secured, the deformation is absorbed, and the deformation is restricted, so that the risk of the tip 31b being caught between the valve rod 41 and the retainer 33 and being damaged is sufficiently eliminated. Is done.
[0040]
Further, since the abutting portions 43a and 43b abut uniformly by the centering action of the spherical abutting portion 43b, the sealing performance is improved.
[0041]
Further, since the movement of the valve rod 41 is stopped by the contact between the spherical contact portion 43b and the retainer 33, excessive deformation of the seal 31 is prevented.
[0042]
Further, when the brake master cylinder is switched to the non-operating state, both contact portions 43a and 43b of the valve rod 41 are separated from the seal 31 and the retainer 33 by a predetermined amount, thereby restricting the liquid flow of both contact portions 43a and 43b. The action can be set appropriately.
[0043]
Further, since the movement of the valve rod 41 is reliably stopped by the retainer 33 made of resin or metal having higher hardness than the seal 31, the reliability of the closing action of the center valve by the seal 31 made of a rubber material is improved.
[0044]
In addition, even if the amount of movement of the valve rod 41 increases and the amount of deformation of the seal tip 31b increases, the amount of deformation of the tip 31b is suppressed by the recess 43c due to the stepped formation. Is done.
[0045]
Moreover, in this embodiment, although the structure which provided the 1st, 2nd contact part in the head 43 of the valve rod 41 and formed in the step shape was demonstrated, it is not limited to such a structure, Both abutting portions may be formed on the concave portion 13 side of the secondary piston 9, and outer and inner members may be provided on the head 43 side of the valve rod 41.
[0046]
Moreover, the taper contact part 43a of this embodiment can also be made into a convex curved surface, and the spherical contact part 43b can also be made into a taper shape.
[Brief description of the drawings]
FIG. 1 is an overall cross-sectional view of an embodiment of the present invention.
FIG. 2 is an enlarged view of a main part of FIG.
FIG. 3 is an enlarged view of a main part of FIG. 2;
[Explanation of symbols]
3 Cylinder body 3b Port (communication path)
5,9 Piston 7 Center valve (valve)
9a Shaft hole (communication path)
9b Horizontal slot (communication path)
9c Communication path 11 Reservoir 13 Recess 25, 27 Hydraulic chamber 31 Seal (outer member)
31b Tip end 33 of the seal Retainer (inner member)
33b End 41 of Retainer Valve Rod 43 Head 43a of Valve Rod Taper Contact Part (First Contact Part)
43b Spherical contact portion (second contact portion)
43c Recess 45 Valve rod rod 47 Spring 49 Space 51 Stopper bolt

Claims (5)

A cylinder body having a hydraulic pressure chamber that is pressurized as the piston accommodated therein moves, the piston being provided in a recess extending in the axial direction and opening at an end facing the hydraulic pressure chamber. Having a communication path for communicating the hydraulic chamber with a hydraulic fluid reservoir via a valve;
In the brake master cylinder, the valve shuts off the communication path when moving the piston and communicates when the piston returns.
The valve comprises a head portion and a rod portion, receives a biasing force of a spring member, and is biased inward in the axial direction of the recess , a concentric annular outer member provided to be positioned in the recess , and An inner member and an abutting portion provided at a head of the valve rod and abutting against the outer member and the inner member, and an abutting side tip provided on an outer side in the axial direction of the outer member It is formed so as to protrude by a predetermined amount toward the axially outer side of the recess from the axially outer end,
The outer member is formed of an easily deformable elastic body, and the inner member is formed to be harder than the outer member,
The abutting portion includes a first abutting portion for sealing that abuts against the abutting-side tip portion of the outer member , and a second abutting portion for centering that abuts against the inner member. While configuring the second contact portion to contact the inner member after the contact portion contacts the outer member,
A taper angle facing the outer member of the first contact portion is set to be larger than a taper angle facing the inner member of the second contact portion, and the first contact portion and the second contact portion A stepped recess is formed therebetween, and the deformation is restricted by the recess when the abutting tip is in contact with the first abutment and deformed radially inward. Characteristic brake master cylinder valve structure. The valve structure of the brake master cylinder according to claim 1,
The valve structure of a brake master cylinder, wherein the first contact portion is formed in a tapered shape. The valve structure of the brake master cylinder according to claim 1 or 2,
The brake master cylinder valve structure, wherein the second contact portion is formed in a convex curved surface. The valve structure of the brake master cylinder according to any one of claims 1 to 3,
A valve structure of a brake master cylinder, wherein the first contact portion and the second contact portion are formed in a stepped shape. The valve structure of the brake master cylinder according to any one of claims 1 to 4,
The valve structure of a brake master cylinder, wherein the outer member is formed of a rubber material, and the inner member is formed of a hard material such as resin or metal having a higher hardness than the outer member.

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