JPH0441030Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a hydraulic master cylinder for a vehicle in which the length of the ineffective stroke can be adjusted.

[Conventional technology]

In a vehicle hydraulic master cylinder, for example, as shown in Japanese Utility Model Application No. 63-82667, a piston is slidably inserted into a cylinder hole formed in a cylinder body to form a hydraulic chamber in the cylinder hole. A relief port communicating between the hydraulic pressure chamber and the reservoir is formed in the cylinder hole, and when the piston moves forward and closes the relief port, the pressure in the hydraulic chamber increases, and the piston connects to the relief port. The pressure in the hydraulic chamber will not rise until the valve is closed, resulting in an invalid stroke.

[The problem that the idea aims to solve]

The operating feeling differs depending on the length of this ineffective stroke, but in conventional master cylinders, the retraction limit of the piston is constant, so it is not possible to adjust the ineffective stroke. For this reason, conventionally, as shown in Japanese Utility Model Publication No. 1834/1983, an adjusting member is provided on the operating lever side that pushes the piston of the master cylinder, and the retraction limit of the piston is made variable to adjust the invalid stroke. Was.

Therefore, an object of the present invention is to provide a hydraulic master cylinder for a vehicle in which the invalid stroke can be adjusted on the master cylinder side.

[Means to solve the problem]

In order to achieve the above object, the present invention has a first means in which a piston is slidably inserted into a cylinder hole formed in a cylinder body to define a hydraulic chamber in the cylinder hole, and a return spring is used. In a vehicle hydraulic master cylinder that urges a piston in a backward direction, a cylinder tube having a cylinder hole formed in the cylinder body is screwed so as to be movable in the axial direction, and the hydraulic pressure chamber and the reservoir are connected to the cylinder tube. The second means is characterized in that a communicating relief port is formed, and in the second means, a piston is slidably inserted into a cylinder hole formed in the cylinder body to define a hydraulic chamber in the cylinder hole, and a return port is formed. A hydraulic master cylinder for a vehicle in which a piston is urged in the backward direction by a spring, characterized in that an adjustment nut is screwed onto the cylinder body to abut on the rear end of the piston and regulate the backward limit, In the means, a piston having a cylindrical space with an open tip is slidably inserted into a cylinder hole of a cylinder body, is biased in a backward direction by a return spring, and a reservoir and a cylindrical space are attached to the piston. The piston is characterized in that a communicating relief port is formed, and a cup seal that closes the relief port when the piston is moved is provided in the cylinder hole so as to be movable in the axial direction.

[Effect]

With the above configuration, the first means changes the position of the relief port and the piston by screwing the cylinder tube, and the second means changes the retraction limit of the piston by screwing the adjustment nut. As a result, the positions of the relief port and the piston are changed, and in the third means, by moving the cup seal, the positions of the relief port and the cup seal are changed, and the lengths of the respective invalid strokes can be adjusted.

〔Example〕

FIG. 1 shows a first embodiment in which the present invention is applied to a front brake master cylinder of a motorcycle.A master cylinder 1 has a cylinder tube insertion hole 3 that is open at both ends in a cylinder body 2, and A cylinder tube 4 is inserted into the tube insertion hole 3 through one opening, and a piston 5 is inserted through the other opening, and working fluid is introduced from a reservoir (not shown) into the center of the cylinder body 2. A hydraulic fluid reservoir 7 is formed on the outer periphery of the cylinder tube 4 into which the connector 6 is inserted.

The cylinder tube 4 has a pressure fluid supply port 9 formed at the bottom of a cylinder hole 8 that opens on the piston 5 side, and a male threaded portion 10 formed on the outer periphery of the supply port 9 side above the pressure fluid is connected to a female threaded portion 11 of the cylinder body 2. They are screwed together and inserted into the cylinder insertion hole 3.

Further, a relief port 12 and a supply port 13 are bored in the cylinder cylinder 4 facing the working fluid reservoir 7 and communicating between the working fluid reservoir 7 and the cylinder hole 8 . An adjustment nut 14 for screwing the cylinder tube 4 is formed at the end.

The piston 5 has a primary cup seal 15 and a secondary cup seal 16, is fluid-tightly and movably inserted into the cylinder hole 8, and has a return spring compressed between it and the bottom of the cylinder hole 8. 17 in the backward direction, and a stop ring 18 fixed to the cylinder hole 8 restricts the limit of the backward movement.

Further, the piston 5 defines a hydraulic chamber 19 between the primary cup seal 15 and the bottom of the cylinder hole 8, and when the piston 5 is pushed forward by the operating lever 20, the primary cup seal 15 closes the relief port 12. When it is closed, the hydraulic pressure in the hydraulic chamber 19 increases, and hydraulic fluid is forcefully delivered from the pressure fluid supply port 9 to the brake mounting (not shown).

The distance l ₁ between the primary cup seal 15 and the relief port 12 is the distance l 1 between the primary cup seal 15 and the relief port 12.
9 does not increase, resulting in an invalid stroke. However, in this embodiment, since the cylinder tube 4 is screwed onto the cylinder body 2, by rotating the adjustment nut 14 and screwing the cylinder tube 4, the cylinder tube 4 is screwed. , the cylinder tube 4 moves in the axial direction to change the distance between the primary cup seal 15 and the relief port 12, making it possible to adjust the length of the ineffective stroke.

Note that the distance _l2 between the end face of the adjuster nut 14 and the end of the cylinder body 2 is set to be equal to or less than the distance _l1 between the primary cup seal 15 and the relief port 12.

FIG. 2 shows a second embodiment in which the present invention is applied to a rear brake master cylinder of a motorcycle.
A piston insertion hole 23 is formed in which both ends are open, and
The piston 24 is inserted into the piston insertion hole 23 from one opening, and the cap seal holding member 25 is inserted from the other opening, and the hydraulic fluid from a reservoir (not shown) is inserted into the center of the cylinder body 22. A connector 26 is provided for introducing the hydraulic fluid, and a hydraulic fluid reservoir 2 is provided on the outer periphery of the piston 24 inside the connector 26.
7 is formed.

The piston 24 has a cylindrical space 28 serving as a cylinder hole, and a primary cap seal 29 and a secondary cap seal 29 attached to the cap seal holding member 25 from the other end opening side of the cylinder body 22 are inserted into the cylindrical space 28. A cup seal 30 is inserted to define a hydraulic chamber 31 between the primary cup seal 29 and the bottom of the cylindrical space 28 .

The cup seal holding member 25 has a primary cup seal 29 and a secondary cup seal 3 on the outer periphery.
0 is attached, a pressure fluid supply hole 32 is formed in the shaft core, and a male threaded part 34 on the outer periphery of the flange part 33 is connected to a female threaded part 3 formed in the other end opening of the cylinder body 22.
5 and is fixed to the cylinder body 22.

Further, the piston 24 has a relief port 36 facing the working fluid reservoir 27 and communicating between the working fluid reservoir 27 and the cylindrical space 28 between the primary cup seal 29 and the bottom of the cylindrical space 28 . However, a supply port 37 is provided between the primary cup seal 29 and the secondary cup seal 30 to communicate the working fluid reservoir 27 and the cylindrical space 28.

Furthermore, the piston 24 is connected to the tip of the cylindrical space 28 and the flange 33 of the cap seal holding member 25.
A female threaded portion 39 formed at an opening at one end of the cylinder body 22 is urged in the backward direction by a return spring 38 contracted between
The retraction limit is regulated by an adjuster nut 40 screwed into.

The distance l ₂ between the end face of the adjuster nut 40 and the open end of the cylinder body 22 is set to be equal to or less than the distance l ₁ between the primary cup seal 29 and the relief port 36 .

With this configuration, by changing the retraction limit of the piston 24 by screwing the adjuster nut 40, the distance between the primary cup seal 29 and the relief port 36 is changed, and the length of the invalid stroke can be adjusted.

FIG. 3 shows a third embodiment of the present invention. Since the master cylinder 41 has a structure very similar to that of the master cylinder of the second embodiment, the same reference numerals are given to the same elements. Although the explanation will be omitted, the piston 24 in this embodiment is limited in its backward movement by a stop ring 42 fixed to the opening at one end of the cylinder body 22.

Further, the cup seal holding member 25 connects the male threaded portion 34 on the outer periphery of the flange portion 33 to the cylinder body 22.
Screwed into a female threaded portion 35 formed in the opening at the other end,
By rotating an adjuster nut 43 formed at the outer end of the flange portion 33, the primary cup seal 29 and the secondary cup seal 30 are made movable in the axial direction.

Therefore, when the adjuster nut 43 is rotated, the cup seal holding member 25 is screwed and the primary cup seal 29 and the secondary cup seal 3 are rotated.
0 in the axial direction, the distance between the primary cup seal 29 and the relief port 36 changes,
The length of the invalid stroke can be adjusted.

[Effect of idea]

As described above, the present invention provides a master cylinder in which the pressure inside the hydraulic chamber is increased by closing the relief port formed in the cylinder hole with a cup seal attached to the piston. The second means makes it possible to change the retraction limit of the piston, and the third means makes the cup seal that closes the relief port formed in the piston movable in the axial direction. So,
The distance between the cup seal and the relief port can be changed, making it possible to adjust the length of the invalid stroke.
You can select the operation feeling.

[Brief explanation of the drawing]

Fig. 1 is a sectional front view showing the first embodiment of the present invention, Fig. 2 is a sectional front view showing the second embodiment, and Fig. 3 is a sectional front view showing the second embodiment.
The figure is a sectional front view showing the third embodiment. 1, 21, 41...Master cylinder, 2, 22
...Cylinder body, 3...Cylinder tube insertion hole,
4... Cylinder tube, 5... Piston, 8... Cylinder hole, 12... Relief port, 14... Adjustment nut, 15... Primary cup seal, 17... Return spring, 19... Hydraulic pressure chamber, 23... ... Piston insertion hole, 24 ... Piston, 25 ... Cup seal holding member, 28 ... Cylindrical space, 29 ... Primary cup seal, 3
1... Hydraulic pressure chamber, 36... Relief port, 38...
...Return spring, 40, 43...Adjustment nut.

Claims (1)

[Claims for Utility Model Registration] 1. A piston is slidably inserted into a cylinder hole formed in a cylinder body to define a hydraulic chamber in the cylinder hole, and the piston is urged in the backward direction by a return spring. In the master cylinder for a vehicle that operates, a cylinder tube having a cylinder hole formed in the cylinder body is screwed so as to be movable in the axial direction, and a relief port is formed in the cylinder tube to communicate the hydraulic pressure chamber and the reservoir. A vehicle hydraulic master cylinder featuring: 2. A master cylinder for a vehicle in which a piston is slidably inserted into a cylinder hole formed in a cylinder body to define a hydraulic chamber within the cylinder hole, and the piston is biased in the backward direction by a return spring, A hydraulic master cylinder for a vehicle, characterized in that an adjuster nut is screwed onto the cylinder body to abut against a rear end of the piston to regulate a backward limit. 3. A piston having a cylindrical space whose tip is open is slidably inserted into the cylinder hole of the cylinder body, biased in the backward direction by a return spring, and the piston is communicated with the reservoir and the cylindrical space. 1. A hydraulic master cylinder for a vehicle, characterized in that a relief port is formed, and a cup seal that closes the relief port when the piston moves forward is provided in the cylinder hole so as to be movable in the axial direction.