JP2004237751A - Center valve type hydraulic master cylinder for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stopper ring to be attached onto a piston at a low price by pressing, to exhibit excellent assembling efficiency of a stopper pin and the stopper ring, and to surely prevent the stopper pin from being slipped out. <P>SOLUTION: In this center valve type hydraulic master cylinder for vehicle, the stopper ring 23 is formed by a ring body by rolling a band shaped board material. The ring body is provided with confronting insertion holes 26 through which both ends 22a, 22a of the stopper pin 22 are inserted, and a plurality of protrusions 27 protruding from an outer peripheral surface of the ring body and arranged in rows along the peripheral direction of the ring body. The both ends 22a, 22a of the stopper pin 22 inserted into an insertion hole 20 formed on a rear shaft 6b of a primary piston 6 are inserted into the insertion holes 26, 26 of the stopper ring 23 fitted on the rear shaft 6b, and a fitting clip 29 for preventing the stopper pin 22 from being slipped out is attached on the stopper ring 23. The fitting clip 29 is positioned by the plurality of the protrusions 27, and the stopper pin 22 is surely prevented from being slipped out. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a center valve type vehicle hydraulic master cylinder that hydraulically operates brakes and clutches of various traveling vehicles, and more particularly, to a structure of stopper means including a stopper pin for restricting a retraction limit of a center valve. .
[0002]
[Prior art]
Conventionally, in a center valve type hydraulic master cylinder used as a hydraulic pressure generation source for automobile brakes and clutches, a front shaft of a piston is liquid-tightly inserted into a bottomed cylinder hole formed in a cylinder body, In some cases, a fluid pressure chamber is defined between the front shaft and the bottom of the cylinder hole, and a replenishing fluid chamber is defined between the rear shaft and the cylinder hole. A stem hole that opens to a hydraulic chamber is formed on the central axis of the front shaft, and a radial communication hole that communicates with the stem hole and the replenishing liquid chamber is formed in the rear shaft. Is provided with a stopper pin that abuts on the rear end of the valve stem of the center valve inserted into the stem hole and regulates the retraction limit of the center valve. The stopper pin has both ends protruding from the inside of the communication hole held by a stopper ring externally fitted to the rear shaft. The stopper pin is prevented from coming off by press-fitting the stopper pin into an insertion hole formed in the stopper ring, or by forming a claw portion near the insertion hole to lock the stopper pin.
[0003]
The center valve mounted on the front shaft of the piston is constantly urged toward the opening of the cylinder hole by the resilience of a valve spring. When the piston is in the non-operation position in which the piston is located at the retreat limit side of the cylinder hole opening side, the retreat limit of the center valve is restricted by the rear end of the valve stem abutting on the stopper pin, and the valve body is in the end face of the piston hydraulic pressure chamber side. The hydraulic chamber and the replenishing liquid chamber communicate with each other through the stem hole and the communication hole while being separated from the valve seat. Also, when the piston moves forward from the retreat limit position toward the hydraulic pressure chamber, the contact between the rear end of the valve stem and the stopper pin separates, and the valve body opposes the resilient force of the valve spring to the piston hydraulic chamber side. By sitting on the valve seat on the end face, the communication between the above-mentioned hydraulic chamber and the replenishing liquid chamber is interrupted (for example, see Patent Document 1).
[0004]
[Patent Document 1]
JP 2001-310728 A (page 1-2, FIG. 2)
[0005]
[Problems to be solved by the invention]
However, in the above-described configuration, the stopper ring is provided with a stopper member through which a stopper pin insertion hole is formed in a ring member having a diameter attachable to the rear end shaft of the piston. Since it is formed by processing a groove or the like, it takes time and effort to manufacture the stopper ring. Also, the stopper pin is prevented from dropping by pressing both ends of the stopper pin into the insertion holes or supporting the stopper pins with the claw portions, so that assembling the stopper pin and the stopper ring is troublesome, and the manufacturing cost increases. Was.
[0006]
Therefore, the present invention provides a stopper ring to be mounted on a piston by press working and provides the stopper ring at a low cost, as well as good assemblability of the stopper pin and the stopper ring, and inexpensive and reliable stopping of the stopper pin. It is an object of the present invention to provide a center valve type hydraulic master cylinder for a vehicle that can be used.
[0007]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the present invention provides a liquid discharge device in which a front shaft of a piston is liquid-tightly inserted into a bottomed cylinder hole formed in a cylinder body, and a liquid is interposed between the front shaft and a cylinder hole bottom side. A pressure chamber is defined, a stem hole that opens to the hydraulic chamber is formed on the central axis of the front shaft, and a replenishing fluid chamber is provided between a rear shaft of the piston extending rearward from the front shaft and the cylinder hole. A radial communication hole communicating with the stem hole and the replenishing liquid chamber is formed through the rear shaft, and a valve stem of a center valve is inserted through a hydraulic chamber opening side of the stem hole. A stopper pin that abuts on the rear end of the valve stem and restricts the retraction limit of the center valve is disposed in the communication hole, and both ends of the stopper pin protruding from the communication hole are externally fitted to the rear shaft. Center valve type hydraulic master cylinder held by the stopper ring The stopper ring is formed of a ring body formed by rolling a band-shaped plate material, and the ring body protrudes from the outer peripheral surface of the ring body with opposed insertion holes through which both ends of the stopper pin are inserted, A plurality of projections arranged in a plurality of rows in a circumferential direction of the ring body are formed, and a plurality of ring-shaped locking clips for preventing a stopper pin inserted into the insertion hole from coming off are provided in the plurality of rows of the stopper ring. It is characterized in that it is mounted between the projections arranged on the rim.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. The hydraulic master cylinder 1 is a tandem type used for a two-system brake, and has a bottomed cylinder hole 3 formed in a cylinder body 2 and two primary and secondary hydraulic pressure generating units. 4, 5 are provided in series.
[0009]
A primary hydraulic pressure generating unit 4 is disposed on the opening side of the cylinder hole 3, and a primary piston 6 used in the hydraulic pressure generating unit 4 accommodates a front outer peripheral flange 6 a in the cylinder hole 3. The rear shaft 6b is inserted into the piston guide unit 7 fitted in the large-diameter opening 3a of the cylinder hole 3 and held on the cylinder center axis.
[0010]
A cup seal 8 is fitted to the front of the flange 6a, and a replenishing liquid chamber 9 is defined between the cylinder 6 and the rear shaft 6b sandwiched between the flange 6a and the piston guide unit 7. The liquid chamber 9 and the inside of the reservoir union 10 provided integrally with the upper part of the cylinder body 2 communicate with each other through a liquid communication hole 11.
[0011]
In front of the primary piston 6, a secondary piston 12 used for the secondary hydraulic pressure generating unit 5 disposed on the bottom side of the cylinder hole 3 is accommodated, and a cup seal 13 of the secondary piston 12 and the primary piston 12 are accommodated. The liquid pressure chamber 14 on the primary side is liquid-tightly defined between the pressure chamber 6 and the cup seal 8.
[0012]
A valve case 15 is provided on the front end side of the front shaft 6 c of the primary piston 6 so as to protrude into the hydraulic chamber 14, and the valve case 15 and a spring retainer 16 provided at the rear of the secondary piston 12 are connected to the connection shaft 17. Connected. Further, a return spring 18 is contracted between the valve case 15 and the spring retainer 16.
[0013]
The primary piston 6 is provided with a stem hole 19 and a communication hole 20 in series. The stem hole 19 is provided on the central axis of the front shaft 6c of the primary piston 6 so as to open to the front end face. The communication hole 20 is provided on the rear shaft 6b continuously to the rear end of the stem hole 19, 6b is formed so as to penetrate in the disk radial direction orthogonal to the central axis of 6b. The hydraulic chamber 14 and the replenishing liquid chamber 9 communicate with each other via the stem hole 19 and the communication hole 20. A recess 6d is formed in the rear shaft 6b of the primary piston 6, and a push rod is inserted into the recess 6d.
[0014]
A valve stem 21 a of a center valve 21 is inserted into the stem hole 19, and a stopper pin 22 is provided in the communication hole 20 so as to penetrate in a direction perpendicular to the cylinder axis, and both ends 22 a and 22 a of the stopper pin 22 are , And is supported by a stopper ring 23 mounted outside the communication hole. The stem hole 19 is formed to have a larger diameter than the valve stem 21a, so that the working fluid can flow outside the valve stem 21a. The communication hole 20 has an oval shape that is long in the axial direction of the piston. The communication hole 20 allows the flow of the hydraulic fluid similarly to the stem hole 19 and allows the primary piston 6 to move through the cylinder hole 3.
[0015]
A valve chamber 24 is defined inside the valve case 15, and a valve body 21 b at the head of the center valve 21 is disposed in the valve chamber 24, and an opening 15 a is provided in the valve case 15 so that the valve chamber 24 is It communicates with the chamber 14. A valve spring 25 is contracted between the valve case 15 and the valve body 21b to urge the center valve 21 toward the opening of the cylinder hole, and the front end face of the primary piston 6 in which the stem hole 19 is opened. Is a valve seat 6e on which the valve body 21b is seated.
[0016]
The stopper ring 23 is provided with insertion holes 26, 26 through which both end portions 22a, 22a of the stopper pin 22 are inserted into the strip-shaped plate member, and a plurality of rows (two rows in this embodiment) on both sides in the longitudinal direction. Are formed at once by press working, and the band-shaped plate is rolled to form a ring body R formed in a ring shape. The ring body R has a diameter that can be externally fitted to the rear shaft 6b of the primary piston 6, and when processed into a ring shape, the insertion holes 26, 26 are arranged facing the center line of the ring body R. The plurality of protrusions 27 project from the outer peripheral surface of the ring body R and are processed so as to be arranged in two rows in the circumferential direction.
[0017]
The stopper ring 23 thus formed is inserted from the rear end of the primary piston 6 to the rear shaft 6b, and is fitted to the outside of the communication hole. The stopper pin 22 is inserted from one insertion hole 26 of the stopper ring 23 attached to the outside of the communication hole toward the other insertion hole 26, and the stopper pin 22 is disposed in the direction perpendicular to the cylinder axis of the communication hole 26. . Next, a locking clip 29 is attached to the outer periphery of the stopper ring 23, and is brought into contact with both ends 22a, 22a of the stopper pin 22 inserted through the insertion holes 26, 26 to prevent the stopper pin 22 from coming off.
[0018]
The locking clip 29 is formed by winding a wire into a ring shape and having an elastic force in a diameter reducing direction. The locking clip 29 is inserted into the rear shaft 6 b from the rear end of the primary piston 6 while being pushed open in the diameter expanding direction. The push-opening force in the radially expanding direction is released at the position where it comes into contact with both ends 22 a, 22 a, and is mounted on the stopper ring 23. The locking clip 29 thus mounted is disposed between the two rows of projections 27 formed on the stopper ring 23 and positioned there. The position of the locking clip 29 is determined by the both ends 22 a of the stopper pin 22. , 22a.
[0019]
In the master cylinder 1 of the present embodiment formed as described above, when the brake is not applied, the center valve 21 urged in the direction of the cylinder hole opening by the valve spring 25 has the rear end of the valve stem 21 a with the stopper pin 22. The valve body 21b in the valve chamber 24 is separated from the valve seat 6e by a predetermined distance, and the hydraulic chamber 14 and the replenishing liquid chamber 9 are separated from the valve chamber 24 by the stem hole. 19 and a communication hole 20.
[0020]
Also, during braking, the primary piston 6 moves forward through the cylinder hole 3 toward the bottom against the elastic force of the return spring 18. In the early stage of the advance of the primary piston 6, no pushing force acts on the center valve 21 and the stopper ring 23. Therefore, the center valve 21 and the stopper ring 23 are continuously in the stop position, and the valve seat 6e is gradually moved by the advance of the primary piston 6. Approaching the valve body 30a.
[0021]
When the valve element 21b is seated on the valve seat 6e, a pushing force is applied from the primary piston 6 to the center valve 21, the center valve 30 leaves the stopper ring 22 while leaving the stopper ring 23 at the non-operation position, and the primary piston 6 At the same time, it starts to advance toward the bottom of the cylinder hole 3. When the primary piston 6 and the center valve 21 advance, and the stopper pin 22 abuts on the side wall of the cylinder hole opening of the communication hole 20, the stopper ring 23 and the stopper pin 22 are integrated with the primary piston 6 and the center valve 21. And moves toward the bottom of the cylinder hole 3.
[0022]
The communication between the hydraulic pressure chamber 14 and the replenishing liquid chamber 9 is interrupted by the valve body 21b sitting on the valve seat 6e, and the hydraulic fluid inside the hydraulic pressure chamber 14 is increased in pressure as the primary piston 6 advances. The hydraulic fluid pressurized in the hydraulic chamber 14 is sent from an output port opened on the peripheral wall of the cylinder body 2 to a disc brake or a drum brake of a primary brake system to operate these brakes.
[0023]
As described above, in this embodiment, since the stopper ring is formed by press working, it can be manufactured at a low cost, and the manufacturing cost can be reduced, and the assemblability of the stopper ring, the stopper pin, and the locking clip is good. Also, the stopper pin can be reliably and inexpensively prevented.
[0024]
In the present embodiment, a plurality of projections are arranged in two rows in the circumferential direction of the ring body. However, in the present invention, a plurality of projections may be arranged in two or more rows. By disposing the projections in two or more rows, it is possible to provide two or more locking clips, and it is possible to more reliably prevent the stopper pins from coming off. The hydraulic master cylinder for a vehicle according to the present invention can be applied to a single system of a single type in addition to the tandem type shown in the embodiment.
[0025]
【The invention's effect】
As described above, according to the present invention, a stopper ring for holding the stopper pin for restricting the retreat limit of the valve stem in the communication hole of the piston can be manufactured at low cost by press working, and the manufacturing cost can be reduced. Reduction can be achieved. Also, the assemblability of the stopper ring and the stopper pin is good, the stopper pin can be prevented from coming off inexpensively and securely, and the retreat limit of the valve stem can be regulated reliably. Operation can be maintained.
[Brief description of the drawings]
FIG. 1 is a cross-sectional front view of a main part of a center valve type hydraulic master cylinder showing an embodiment of the present invention. FIG. 2 is a perspective view showing a ring body before roll processing showing an embodiment of the present invention. FIG. 4 is a perspective view showing a state in which a stopper ring, a stopper pin, and a locking clip are shown in an embodiment of the present invention; FIG. 4 is a sectional front view of a center valve type hydraulic master cylinder showing an embodiment of the present invention; Description】
DESCRIPTION OF SYMBOLS 1 ... Hydraulic master cylinder, 2 ... Cylinder body, 3 ... Cylinder hole, 4, 5 ... Hydraulic pressure generating unit, 6 ... Primary piston, 6a ... Flange, 6b ... Rear shaft, 6c ... Front shaft, 9 ... Replenishing liquid Chamber, 10: reservoir union, 14: hydraulic chamber, 19: stem hole, 20: connecting hole, 21: center valve, 21a: valve stem, 21b: valve body, 22: stopper pin, 22a: end, 23 ... Stopper ring, 26: communication hole, 27: projection, 28: lightening portion, 29: locking clip, R: ring body

Claims (1)

A front shaft of the piston is liquid-tightly inserted into a bottomed cylinder hole formed in a cylinder body, and a hydraulic chamber is defined between the front shaft and a bottom side of the cylinder hole. A stem hole that opens to the hydraulic chamber is formed on the central axis of the piston, a replenishing liquid chamber is defined between a rear shaft of the piston extending rearward from the front shaft and a cylinder hole, and the stem is formed in the rear shaft. A radial communication hole communicating with the hole and the replenishing liquid chamber is formed so as to penetrate therethrough, a valve stem of the center valve is inserted from the hydraulic pressure chamber opening side of the stem hole, and the center valve is brought into contact with the rear end of the valve stem. A center valve type liquid in which a stopper pin for restricting the retraction limit is disposed in the communication hole, and both ends of the stopper pin protruding from the communication hole are held by a stopper ring externally fitted to the rear shaft. In the pressure master cylinder, the stopper ring lowers the band-shaped plate material. The ring body is formed by processing, and the ring body has opposed insertion holes through which both ends of the stopper pin are inserted, and protrudes from the outer peripheral surface of the ring body, and is formed in a plurality of rows in the circumferential direction of the ring body. A plurality of projections to be provided are formed, and a ring-shaped locking clip for retaining a stopper pin inserted into the insertion hole is mounted between the projections arranged in a plurality of rows of the stopper ring. A center valve type hydraulic master cylinder, characterized in that:

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