JPH0658241U - Center valve type master cylinder - Google Patents

Abstract

(57) [Summary] [Structure] At the retracted position of the piston 2, the slide valve is inserted into the opening 4 formed in the axial direction of the piston 2 and the stopper member 5 fixed to the cylinder body side is brought into contact with the slide valve. In a center valve type master cylinder in which residual pressure on the pressure chamber side is eliminated through through holes formed at both ends of the slide valve by moving relative to the piston, the outer periphery of the stopper member It is characterized in that a collar 17 made of resin or the like is rotatably loosely fitted on the surface. [Effect] Since the rotatable collar is interposed between the opening 4 formed in the piston and the stopper member 5, it is possible to prevent the stopper member from being locally worn by the forward and backward movement of the piston, and at the same time, to prevent the collar from wearing. It is possible to prevent the stopper member from being caught by the rotation of the piston and causing a malfunction.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a master cylinder for hydraulic pressure generation used for clutch actuation and the like, and more particularly to an improvement to a stopper member for a slide valve in a center valve type master cylinder.

[0002]

[Prior art]

 3 to 5 show an example of a conventional structure of this type of center valve type master cylinder. FIG. 3 is a vertical sectional view showing the entire master cylinder, and FIG. 4 is a sectional view taken along a stopper member. FIG. 5 is an enlarged vertical sectional view of the cylinder portion showing FIG. 5, and FIG. 5 is an enlarged view showing a state after using the stopper member. In the figure, 1 is a cylinder body, 2 is a piston fitted in the cylinder body 1, and the piston 2 is pushed in the cylinder body 2 by a push rod 3 linked to a clutch pedal or the like (not shown). Is configured. An opening 4 that penetrates vertically is formed in the axial direction of the piston 2, and a stopper member 5 screwed to the cylinder body 1 side is inserted into the opening 4. A cylindrical slide valve 6 having through holes at both ends is slidably supported at the tip of the piston 2 while being biased rearward by a spring or the like. In the figure, 7 and 8 are sealing means attached to the piston 2, 9 is a pressing support portion of the slide valve 6, 10 is a pressure chamber, 11 is a return spring for the piston 2, and 12 is an oil tank. Replenishment connection parts to be connected, 13 are output connection parts connected to the clutch actuating part, and 14 and 15 are mounting holes. Then, in the above structural example, when the clutch pedal (not shown) is depressed and the push rod 3 advances to the right in the figure, the piston 2 advances to the right, and the end portion of the slide valve 6 moves accordingly. Since it moves away from the stopper member 5 relatively to the left, the through hole at its tip is closed and the end face of the pressing support part 9 is joined to the end face of the piston 2, and at the same time the pressure chamber 10 is pressed. The pressure action is started. As a result, hydraulic pressure is output from the output connection portion 13 to activate the clutch. When the foot on the clutch pedal is loosened, the return spring 11 causes the piston 2 to return to the left. When the piston 2 returns to the left end retracted position, the left end of the slide valve 6 comes into contact with the stopper member 5 and relatively moves to the right, and the through holes formed at both ends thereof. However, the residual pressure on the pressure chamber 10 side is eliminated through these through holes.

[0003]

[Problems to be solved by the device]

 By the way, in the above-mentioned conventional master cylinder, since the sliding operation is repeated with the stopper member 5 being inserted into the opening 4 formed in the axial direction of the piston 2, the sliding movement is repeated for a long period of time. As shown in (1), the abrasion portion 16 is generated, which may be caught by the piston 2 and cause malfunction. The present invention has been made in view of this point, and an object thereof is to provide an improvement for avoiding local wear of the stopper member as in the conventional case.

[0004]

[Means for Solving the Problems]

 In order to solve the above problems, the present invention provides a cylinder body, a piston slidably fitted into the cylinder body and pushed by a push rod, and slidably mounted on the piston. It is composed of a cylindrical slide valve having a through hole formed in it and a stopper member that is inserted into an opening formed in the axial direction of the piston and is fixed to the cylinder body side. When the slide valve comes into contact with the stopper member and moves relative to the piston, residual pressure on the pressure chamber side is eliminated through through holes formed at both ends of the slide valve. In the center valve type master cylinder described above, a collar made of resin or the like is rotatably loosely fitted on the outer peripheral surface of the stopper member.

[0005]

[Action]

 As described above, in the present invention, since the color of resin or the like is rotatably loosely fitted to the outer peripheral surface of the stopper member, the stopper member 5 is rotatable between the opening 4 formed in the piston 2 and the stopper member 5. Since the collar is interposed, it is possible to prevent the outer peripheral surface of the stopper member 5 from being worn by the back and forth movement of the piston 2.

[0006]

【Example】

 An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. The basic structure of the master cylinder does not differ from the above-described conventional structure example, and therefore the description thereof will be cited and will not be repeated here, and only the characteristic part will be described. FIG. 1 is an enlarged vertical sectional view of a cylinder portion showing a case of an embodiment of the present invention, which is a sectional view taken along a stopper member 5, FIG. 2 is an enlarged view of the stopper member 5, (A) is a vertical sectional view thereof, (B) is a perspective view of a collar. As shown in FIGS. 1 and 2, the present embodiment is characterized in that the collar 17 is rotatably loosely fitted on the outer peripheral surface of the stopper member 5. It is preferable that the collar 17 is made of a material such as resin having a relatively small coefficient of friction and having good workability and corrosion resistance. Further, as shown in the perspective view of FIG. 2B, recesses 18 and 19 for oil penetration are formed on both end surfaces of the collar 17, and a groove portion connecting the recesses 18 and 19 to the inner surface thereof. If 20 is formed, the oil penetrates into the contact surface between the stopper member 5 and the collar 17 and exerts a lubricating action, so that the rotation of the collar 17 becomes smoother. When the piston 2 slides back and forth in the cylinder body 1, the stopper member 5 comes into contact with the opening 4 formed in the piston 2 through the rotatable collar 17, so that the collar 17 is held. Will make relative movement while rotating. Therefore, local wear of the stopper member 5 is avoided, and further, a situation in which the stopper member 5 is caught in the opening 4 and obstructs the operation of the piston 2 is prevented. The specific material and length of the collar 17 may be selected in consideration of the cross-sectional shape of the opening 4 formed in the piston 2 and the usage conditions.

[0007]

[Effect of device]

 As described above, according to the present invention, the opening 4 formed in the piston 2 and the stopper member 5 are formed by adding the simple structure in which the collar made of resin or the like is rotatably loosely fitted to the outer peripheral surface of the stopper member. The rotatable collar interposed between these eliminates the local wear of the stopper member 5 due to the back and forth movement of the piston 2 and prevents the rotation of the collar from catching the piston 2 and causing a malfunction.

[Brief description of drawings]

FIG. 1 is an enlarged vertical sectional view of a cylinder portion according to an embodiment of the present invention.

FIG. 2 is an enlarged part view of a stopper member in the embodiment.

FIG. 3 is a vertical cross-sectional view showing the entire conventional master cylinder.

FIG. 4 is an enlarged vertical sectional view of a cylinder portion in the conventional example.

FIG. 5 is an enlarged view of the stopper member showing a state after use.

[Explanation of symbols]

 1 ... Cylinder body 2 ... Piston 3 ... Push rod 4 ... Opening part 5 ... Stopper member 6 ... Slide valve 9 ... Pressing support part 10 ... Pressure chamber 16 ... Wear part 17 ... Collar 18 , 19 ... Recessed part 20 ... Groove

Claims (1)

[Scope of utility model registration request] 1. A cylinder body, a piston slidably fitted in the cylinder body, and pushed by a push rod, and a piston slidably mounted on the piston and having through holes formed at both ends thereof. A cylindrical slide valve and a stopper member that is inserted into an opening formed in the axial direction of the piston and fixed to the cylinder body side. A center valve type master cylinder in which residual pressure on the pressure chamber side is eliminated through through holes formed at both ends of the slide valve by moving relative to the piston by abutting against a member. A center valve type master cylinder in which a collar made of resin or the like is rotatably fitted on the outer peripheral surface of the stopper member.