CN108105279B

CN108105279B - Clutch release mechanism and clutch master cylinder

Info

Publication number: CN108105279B
Application number: CN201611052926.0A
Authority: CN
Inventors: 刘向东
Original assignee: Schaeffler Technologies AG and Co KG
Current assignee: Schaeffler Technologies AG and Co KG
Priority date: 2016-11-25
Filing date: 2016-11-25
Publication date: 2021-02-12
Anticipated expiration: 2036-11-25
Also published as: CN108105279A

Abstract

A clutch release mechanism and a clutch master cylinder, wherein the clutch master cylinder includes: the piston is positioned in the piston cavity; the piston cavity part at one axial side of the piston is a hydraulic cavity, the cylinder body is provided with a first oil conveying part communicated with the hydraulic cavity, the peripheral surface of the piston is provided with an oil groove, and the cylinder body is provided with a second oil conveying part communicated with the oil groove; an oil passage is arranged in the piston and is communicated with the hydraulic cavity and the oil groove; an on-off part is arranged in or outside the oil duct and is axially opposite to the piston; under the action of oil pressure in the hydraulic cavity, the on-off piece can abut against the piston to block the oil passage and the hydraulic cavity; under the action of oil pressure in the oil duct, the on-off piece can be separated from the piston so that the oil duct is communicated with the hydraulic cavity. Utilize this technical scheme's clutch master cylinder, after stepping on rapidly, loosen the clutch pedal, when stepping on the clutch pedal again immediately, the idle stroke because of the vacuum production can no longer appear, and the driver can immediately experience and step on the sense, promotes the operation experience nature of product.

Description

Clutch release mechanism and clutch master cylinder

Technical Field

The invention relates to the technical field of clutches, in particular to a clutch release mechanism and a clutch master cylinder.

Background

The clutch separating mechanism comprises a clutch main cylinder, and the clutch main cylinder comprises a cylinder body with a piston cavity and a piston positioned in the piston cavity. The piston cavity part of one axial side of the piston is a hydraulic cavity, the other side of the piston is connected with a piston rod, and the piston rod is connected to the clutch pedal. The hydraulic cavity can be filled with hydraulic oil, the cylinder body is provided with a first oil conveying part communicated with the hydraulic cavity, and the hydraulic cavity is communicated with the hydraulic separation system through the first oil conveying part.

When the clutch pedal is stepped on, the piston rod can drive the piston to move into the hydraulic cavity, and the hydraulic oil is extruded to be output to the hydraulic separation system from the first oil conveying part so as to drive the clutch to separate. The driver quickly puts down the clutch pedal, the piston and the piston rod can be quickly reset, and in the process, the speed of hydraulic oil in the hydraulic separation system flowing back to the hydraulic cavity is slow, so that the hydraulic cavity cannot be immediately filled with the hydraulic oil, and vacuum can be formed in the hydraulic cavity.

However, if the driver subsequently depresses the clutch pedal, the resulting lost motion of the vacuum will be overcome and there will be a feeling of depression, which will reduce the operational experience of the product.

Disclosure of Invention

The invention solves the problem that the operation experience of the existing clutch release mechanism is poor.

To solve the above problems, the present invention provides a clutch master cylinder including: the piston is positioned in the piston cavity; the piston cavity part on one axial side of the piston is a hydraulic cavity, the cylinder body is provided with a first oil conveying part communicated with the hydraulic cavity, the peripheral surface of the piston is provided with an oil groove, and the cylinder body is provided with a second oil conveying part communicated with the oil groove; an oil passage is arranged in the piston and is communicated with the hydraulic cavity and the oil groove; an on-off part is arranged in or outside the oil duct, and the on-off part is axially opposite to the piston; under the action of oil pressure in the hydraulic cavity, the on-off piece can abut against a piston to block the oil passage and the hydraulic cavity; under the action of oil pressure in the oil passage, the on-off part can be separated from the piston so that the oil passage is communicated with the hydraulic cavity.

Optionally, the on-off member is disposed in the hydraulic chamber and opposite to the piston.

Optionally, the on-off member includes a base and an extension portion extending from the base in the axial direction away from the hydraulic pressure chamber; the on-off part is axially opposite to the piston through the base body, and at least part of the extending part is positioned in the oil duct and can slide along the oil duct under the action of oil pressure in the hydraulic cavity or the oil pressure in the oil duct; under the action of oil pressure in the hydraulic cavity, the base body abuts against the piston to block the oil passage and the hydraulic cavity; under the action of oil pressure in the oil passage, the base body is separated from the piston so that the oil passage and the hydraulic pressure chamber are communicated.

Alternatively, an inner peripheral surface of the oil passage is provided with a first protrusion portion that surrounds the extension portion.

Optionally, the outer circumferential surface of the extending portion is provided with a second protruding portion, the first protruding portion is located between the second protruding portion and the base body, and the first protruding portion and the second protruding portion have an axial overlapping portion so as to block the on-off member from moving outward of the oil passage and disengaging from the oil passage.

Optionally, the extension portion connects at least one of an outer diameter of a portion of the base body and an inner diameter of the first protrusion portion, at least one of which is gradually reduced in a direction away from the hydraulic pressure chamber.

Optionally, the first protrusion has an axial passage through which oil in the oil passage applies oil pressure to the outer circumferential surface of the extension portion to separate the base from the piston.

Optionally, the axial channel is an axial through slot or an axial through hole.

Optionally, the extension part is provided with a groove along one end face of the piston, which faces away from the base body in the axial direction.

Optionally, an outer diameter of at least a portion of the extension connecting the base body is gradually reduced in a direction away from the hydraulic pressure chamber.

Alternatively, one of the inner peripheral surface of the oil passage and the outer peripheral surface of the extending portion has a groove and the other has a protrusion; the projection is axially movable within the recess along the piston and abuts a corresponding side wall of the recess when the base is separated from the piston.

Optionally, the outer diameter of the base is smaller than the inner diameter of the piston cavity.

Optionally, one of two surfaces of the base body and the piston, which are opposite to each other in the axial direction, is provided with at least one annular groove surrounding a central axis of the oil passage, and the other surface is provided with at least one annular protrusion surrounding the central axis of the oil passage; when the base body abuts against the piston, the protrusions are accommodated in the corresponding grooves and are in sealing arrangement with the grooves; when the base body is separated from the piston, the protrusions are at least partially located outside the corresponding grooves so that the oil passages communicate with the hydraulic pressure chamber.

Optionally, the piston comprises: the piston pin penetrates through the body part along the axial direction and is fixedly connected with the body part, the hydraulic cavity is positioned on one side of the piston pin, which is opposite to the body part, and the oil groove is formed in the outer peripheral surface of the body part; the oil passage is arranged in the piston pin, and the piston is axially opposite to the on-off piece through the piston pin.

The invention also provides a clutch release mechanism comprising any one of the clutch master cylinders.

Compared with the prior art, the technical scheme of the invention has the following advantages:

and the on-off part is arranged in or outside the oil channel. When the clutch is quickly stepped on, the piston can be controlled to move into the hydraulic cavity, high-pressure oil in the hydraulic cavity is extruded to be output from the first oil conveying part, and the clutch is driven to be separated. In the process, under the action of high-pressure oil in the hydraulic cavity, the on-off piece can be axially abutted against the piston to block the oil channel, so that the high-pressure oil in the hydraulic cavity cannot flow into the oil channel.

When the clutch pedal is released quickly, the piston rod drives the piston to move rightwards quickly to reset. In this process, since the oil returning speed from the first oil delivery portion into the hydraulic chamber is slow, vacuum is formed in the hydraulic chamber, and therefore the oil pressure in the hydraulic chamber applied to the on-off member is rapidly reduced. At this time, the low-pressure oil output from the second output portion into the oil passage may flush the on-off member, which can be separated from the piston to communicate the oil passage with the hydraulic pressure chamber. The low-pressure oil in the oil duct can flow into the hydraulic cavity, so that the vacuum in the hydraulic cavity is eliminated. Like this, even step on the clutch pedal again immediately after loosening the clutch pedal, the idle stroke because of the vacuum production can no longer appear, and the driver can immediately experience and step on the sense, promotes the operation experience nature of product.

Drawings

FIG. 1 is a cross-sectional view of a clutch master cylinder according to a first embodiment of the present invention, in which a cut-off member and a piston are in an axially abutting state;

FIG. 2 is an enlarged view of area A of FIG. 1;

FIG. 3 is a sectional view of the clutch master cylinder according to the first embodiment of the present invention, in which the cut-off member and the piston are separated;

FIG. 4 is an enlarged view of area B of FIG. 3;

FIG. 5 is a plan view of a piston pin of the clutch master cylinder of FIG. 1 as viewed in an axial direction;

FIG. 6 is a cross-sectional view taken along direction CC of FIG. 5;

FIG. 7 is a perspective view of a disconnect member of the clutch master cylinder of FIG. 1;

fig. 8 is a sectional view of a piston pin in a clutch master cylinder according to a second embodiment of the present invention, in which a shut-off member and the piston pin are separated from each other.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below.

The clutch release mechanism generally includes a clutch master cylinder disposed between a clutch pedal and a hydraulic release system for transmitting a pedal stroke of the clutch pedal to release the clutch.

First embodiment

Referring to fig. 1, the clutch master cylinder includes: a cylinder 1 having a piston chamber 1a and a piston 2 located in the piston chamber 1 a. The piston cavity part on one axial side of the piston 2 is divided into a hydraulic cavity 1b, and the other axial side is connected with a piston rod 4. The cylinder body 1 is provided with a first oil delivery part 11 communicating with the hydraulic chamber 1b, the outer circumferential surface of the piston 2 is provided with an oil groove 2a, and the cylinder body 1 is provided with a second oil delivery part 12 communicating with the oil groove 2 a. An oil passage 2b is arranged in the piston 2, and the oil passage 2b can communicate the hydraulic cavity 1b and the oil groove 2 a.

An on-off member 3 may be provided outside the oil passage 2 b. Referring to fig. 2, when the clutch pedal is depressed, the piston rod 4 drives the piston 2 to move leftward, and the high-pressure oil in the hydraulic pressure chamber 1b is squeezed and output from the first oil delivery part 11 (see a dotted arrow shown in fig. 1) until the clutch is driven to disengage. In the process, under the action of oil pressure in the hydraulic cavity 1b, the on-off piece 3 can be axially abutted against the piston 2 to seal the oil passage 2b, so that high-pressure oil in the hydraulic cavity 1b cannot flow into the oil passage 2b, and the clutch is ensured to be smoothly separated.

Referring to fig. 3 and 4, the clutch pedal is rapidly released, and the piston rod 4 drives the piston 2 to rapidly move to the right to reset. In this process, since the oil returning speed from the first oil delivery portion 11 into the hydraulic chamber 1b is slow, vacuum is formed in the hydraulic chamber 1b, and thus the oil pressure received by the shut-off member 3 in the hydraulic chamber 1b is rapidly reduced. At this time, the low-pressure oil output from the second output portion 12 into the oil passage 2b may flush the cut-off 3. Under the action of the oil pressure in the oil passage 2b, the on-off member 3 can be separated from the piston 2 so that the oil passage 2b communicates with the hydraulic pressure chamber 1 b. The low-pressure oil in the oil passage 2b can flow into the hydraulic chamber 1b (see the broken-line arrow in fig. 3 and 4), so that the vacuum in the hydraulic chamber 1b is eliminated. Like this, even step on the clutch pedal again immediately after loosening the clutch pedal, the idle stroke because of the vacuum production can no longer appear, and the driver can immediately experience and step on the sense, promotes the operation experience nature of product.

Referring to fig. 1, the on-off member 3 may be disposed in the hydraulic chamber 1b and axially opposite to the piston 2, and end faces of both axial ends of the on-off member 3 may be respectively subjected to oil pressure in the hydraulic chamber 1b and oil pressure in the oil passage 2 a.

The piston 2 may include: the oil seal comprises a body part 20, an oil seal 21 and a piston pin 22, wherein the piston pin 22 sequentially penetrates through the oil seal 21 and the body part 20 along the axial direction to fixedly connect the body part 20 and the oil seal 21, the piston pin 22 is provided with a radial outer flange 23 opposite to the body part 20, and the radial outer flange 23 can press the oil seal 21 on the body part 20 to play a role in fixing connection. The hydraulic chamber 1b may be located on a side of the radially outer flange 23 facing away from the body portion 20. The oil groove 2a is provided on the outer circumferential surface of the body portion 20, and the oil passage 2b is provided in the piston pin 22, and the piston 2 can axially oppose the opening/closing member 3 via the piston pin 22.

The oil seal 21 can block the flow of the high-pressure oil in the hydraulic pressure chamber 1b into the oil groove 2a when the clutch is disengaged. When the clutch is engaged, the piston 2 is positioned at the right side, and the hydraulic chamber 1b is filled with high-pressure oil to maintain the engaged state of the clutch. At this time, the oil seal 21 allows the low pressure oil from the second oil delivery part 12 to flow into the hydraulic chamber 1b from the oil groove 2a by a small amount, and the hydraulic chamber 1b can maintain a high oil pressure state, ensuring the stability of the clutch engagement state. Wherein, the second oil transportation part 12 can be connected with the liquid storage tank through a low pressure oil pipe.

The body part 20 may be provided therein with a mounting groove 20a to be penetrated by the piston pin 22, the piston pin 22 may be fastened in the mounting groove 20a by interference fit, the oil groove 2b may be provided with a through hole 20b, and the oil groove 2b, the through hole 20b, the mounting groove 20a, and the oil passage 2a may be sequentially communicated.

The on-off member 3 can thus be arranged in the hydraulic chamber 1b, the piston pin 22 being axially opposite the on-off member 3 via the radially outer flange 23.

Referring to fig. 1 and 2, the on-off member 3 may include a base 30 and an extension 32, the on-off member 3 being axially opposite to the piston pin 22 through the base 30, the extension 32 being at least partially located within the oil passage 2b and being slidable along the oil passage 2 b. Therefore, when the clutch pedal is depressed, the base 30 is subjected to the oil pressure in the hydraulic pressure chamber 1b, and the opening/closing member 3 moves axially toward the piston 2 until the base 30 abuts against the end surface 220 of the piston pin 22 to block the oil passage 2 b. In this case, the base 30 is sealed in contact with the end face 220, and high-pressure oil is prevented from leaking into the inlet oil passage 2b from between the base 30 and the end face 220 of the piston pin 22, thereby achieving sealing. With combined reference to fig. 3 and 4, when the clutch pedal is released, the extension 32 is subjected to the low oil pressure in the oil passage 2b, and the switching member 3 moves away from the piston 2 until the base 30 is separated from the piston pin 22 to expose the gap G, so that the oil passage 2b communicates with the hydraulic chamber 1b, and the low pressure oil can flow into the hydraulic chamber 1b from the gap G.

The piston 2 faces the base body 30 via the piston pin 22. Referring to fig. 5 and 6 in combination with fig. 4, the end surface 220 of the piston pin 22 facing the basic body 30 may be provided with an annular groove 24 surrounding the central axis of the oil passage 2 b; referring to fig. 7 in conjunction with fig. 4, a surface 300 of the basic body 30 facing the piston pin 22 may be provided with an annular protrusion 31 surrounding the center axis of the oil passage 2 b.

Referring to FIG. 4 in conjunction with FIG. 3, upon separation of the base 30 from the piston pin 22, the protrusion 31 may be at least partially positioned outside the groove 24 to separate from the groove 24 to form an annular gap G. For example, the projection 31 may be entirely disengaged from the recess 24, or the projection 31 may be partially accommodated in the recess 24 with a space between the side walls of the recess 24.

Referring to fig. 2, when the base 30 is axially abutted against the piston pin 22, the protrusion 31 may be accommodated in the groove 24 and be provided in a sealing manner with the groove 24, realizing the sealing oil passage 2 b. The sealing arrangement may be a contact seal, and the protrusion 31 may be in contact with at least the bottom wall of the groove 24, the protrusion 31 and the groove 24 cooperating to provide a sealing effect.

In addition to this, the piston pin can be provided with a projection and the base body of the switching element can be provided with a recess. Or a plurality of bulges and grooves can be respectively arranged between the base body and the piston pin, each bulge can be combined with and separated from the corresponding groove, and the plurality of mutually matched bulges and grooves can improve the sealing effect when the on-off piece is axially abutted against the piston. Therefore, one of the two surfaces of the on-off part and the piston, which are opposite to each other in the axial direction, can be provided with at least one annular groove surrounding the central axis of the oil passage, and the other surface can be provided with at least one annular protrusion surrounding the central axis of the oil passage; when the base body is abutted against the piston, the protrusions are accommodated in the corresponding grooves and are arranged in a sealing mode with the grooves; when the base body is separated from the piston, the protrusions are at least partially located outside the corresponding grooves to allow the oil passages to communicate with the hydraulic pressure chamber.

Referring to fig. 3 and 4, the extension 32 may be partially accommodated in the oil passage 2b when the base 30 of the opening/closing member 3 is separated from the piston 2, resulting in better stability of the opening/closing member 3 with respect to the piston 2.

Referring to fig. 1 and 3, the outer diameter of the base body 30 can be smaller than the inner diameter of the piston chamber 1a, which can save material and reduce the cost of the switch 3. Moreover, since the extension portion 32 may be at least partially defined within the oil passage 2b, the outer diameter of the base 30 is smaller than the inner diameter of the piston chamber 1a, and the on-off member 3 is not easily detached from the piston 2.

Referring to fig. 7 in conjunction with fig. 2, the outer diameter of at least a portion of the extension 32 connected to the base 30 may be gradually reduced in a direction away from the hydraulic chamber 1b to form a truncated conical surface 320. It is expected that the outer diameter of the end of the extension portion 32 that connects the base 30 is large when the opening-closing member 3 abuts axially against the piston 2, and the opening of the oil passage 2b can be closed. Referring to fig. 3 and 4, in the process from the axial abutment of the opening/closing member 3 and the piston 2 to the separation, since the outer diameter of the extension portion 32 is gradually reduced in the direction away from the hydraulic pressure chamber 1b, the extension portion 32 can easily move outward from within the oil passage 2 b.

Referring to fig. 5 and 6, the inner circumferential surface 25 of the oil passage 2b may be provided with a first protrusion 26 surrounding the extension 32. With reference to fig. 2 and 4, the first projection 26 can limit the radial vibration of the extension 32, maintaining the positional stability of the shutter 3. Even when the on-off member 3 moves out of the oil passage 2b, the extension portion 32 can be always defined by being surrounded by the first protrusion 26, preventing the on-off member 3 from falling off the piston 2, which can be achieved by, for example, appropriately designing the length of the extension portion 32. Furthermore, the first protrusion 26 can play a certain guiding role when the opening/closing member 3 moves in the oil passage 2b and out of the oil passage 2b in the axial direction at the opening/closing member 3, maintaining the movement stability of the opening/closing member 3.

The inner diameter of the first projection 25 may be gradually reduced in a direction away from the hydraulic pressure chamber 1b (refer to fig. 1), so that the inner peripheral surface of the first projection 25 also forms a truncated conical surface. The extending portion 32 is capable of moving axially along the oil passage 2b such that the outer peripheral surface of the extending portion 32, which connects at least a portion of the base 30, is sealed in contact with the inner peripheral surface of the first protrusion 25 to block the oil passage 2b and the hydraulic pressure chamber 1b (see fig. 2), or such that the outer peripheral surface has a gap from the inner peripheral surface (see fig. 4), so that the oil passage 2b and the hydraulic pressure chamber 1b can communicate with each other.

Referring to fig. 7, the outer circumferential surface 321 of the extension 32 may be provided with a second protrusion 322. Referring to fig. 2, the first protrusion 26 may be located between the second protrusion 322 and the base 30 in the axial direction of the piston 2, but the oil passage 2b may remain communicated from the first protrusion 26 to the second protrusion 322 without clogging the oil passage 2 b. The first protrusion 26 and the second protrusion 322 may have an axial overlap portion to block the on-off member 3 from moving out of the oil passage 2b and escaping from the oil passage 2 b. The axially overlapping portion, as referred to herein, may mean that projections of the first protrusion 26 and the second protrusion 322 in the axial direction of the oil passage 2b overlap, so that the first protrusion 26 and the second protrusion 322 may form an axial mutual block. Referring to fig. 4, during the process from axial abutment to separation of the opening/closing member 3 and the piston 2, the extension portion 32 may move from the oil passage 2b into the hydraulic pressure chamber 1b, and the first protrusion 26 and the second protrusion 322 may gradually come closer to axial abutment. At this time, the first protrusion 26 and the second protrusion 322 may block each other, and the on-off member 3 may no longer move outward of the oil passage 2b, so that complete disengagement of the on-off member 3 from the piston 2 may be better avoided.

On the other hand, the inner peripheral surface of the first projecting portion 26 is a truncated conical surface whose opening on the end surface 220 side is large in size and whose opening into the oil passage 2b is small in size, which facilitates the mounting of the on-off member 3 with the piston 2. When mounting, the second protrusion 322 can smoothly enter the first protrusion 26 through the larger-size opening, after which the operation breaker 3 continues to move into the oil passage 2b, the second protrusion 322 comes into contact with the inner peripheral surface of the first protrusion 26 and is compressively deformed, until the deformation is released to axially overlap the first protrusion 26 after passing through the smaller-size opening of the first protrusion 26. Therefore, the inner peripheral surface of the first projecting portion 26 is a truncated conical surface, which facilitates the assembly and installation of the on-off member 3.

Referring to fig. 7 in conjunction with fig. 2, an end surface 323 of the extension portion 32 that protrudes into the oil passage 2b may have a groove 32 a. When the switching piece 3 is assembled with the piston 2, the second protrusion 322 can be compressed and deformed more easily into the recess 32a when pressed by the first protrusion 26, so that the assembly process is easily performed. Thus, it is contemplated that the groove may extend at least to a position radially opposite the second projection.

Referring to fig. 5, the first projection 26 may be provided with an axial through slot 260 as an axial passage that may maintain communication on both axial sides of the first projection 26. Meanwhile, referring to fig. 2, the second protrusion 322 may have a gap from the inner circumferential surface 25 of the oil passage 2b such that both axial sides of the second protrusion 322 communicate. This can ensure that the oil passage 2b remains communicated from the first protrusion 26 to the second protrusion 322. Referring to fig. 4, the oil in the oil passage 2b may apply oil pressure to the outer circumferential surface of the extension 32 through the through groove 260 to separate the base 30 from the piston 2.

In addition to this, the first projection may be provided with an axial through hole as a passage so that the first projection communicates axially on both sides.

As a modification, one of the inner peripheral surface of the oil passage and the outer peripheral surface of the extended portion has a groove and the other has a protrusion; the protrusion can move axially along the piston in the groove and abut against the corresponding side wall of the groove when the base body is separated from the piston so as to prevent the on-off piece from falling off from the piston. In this case, it is contemplated that the projection may be provided with an axial through groove or an axial through hole as a passage, or a gap between the projection and the bottom wall of the groove, which allows communication between both axial sides of the projection.

Second embodiment

Referring to fig. 8, at an end axially distant from the hydraulic pressure chamber 1b (in conjunction with fig. 1), the inner circumferential surface 25 'of the oil passage 2b' is provided with a first protrusion 26', the first protrusion 26' surrounds the extended portion 32 'of the breaking member 3', and the piston is axially opposite to the base 30 'through the first protrusion 26'.

The extension 32' may have a passage 32b formed therein, and the passage 32b communicates with both axial sides of the first projection 26' when the base 30' is separated from the piston. The passage 32b has a first opening 324 and a second opening 325, the first opening 324 being formed in an end surface of the extension portion 32' on a side of the first projection 26' axially away from the hydraulic pressure chamber 1b '; the second opening 325 is formed at a portion of the outer circumferential surface of the extension 32 'adjacent to the base 30'. At least when the switch 3' is separated from the piston, the first opening 324 and the second opening 325 of the passage 32b are located on both axial sides of the first projection 28, respectively, so that both axial sides of the first projection 28 communicate. Also, it is achievable that the base body 30' axially abuts against the first protrusion 26', and the first opening 324 may be blocked from passing oil into the oil passage 2b '.

This manner of providing the passage 32b in the extension 32' can be applied to the first embodiment. Therefore, at least one of the first protrusion and the extension has a passage, and when the base is separated from the piston, the passage communicates both sides of the first protrusion in the axial direction.

The second protrusion 322' may be located outside the oil passage 2b ' and, at least when the on-off piece 3' is separated from the piston, the second protrusion 322' may axially abut the first protrusion 26 '.

Although the present invention is disclosed above, the present invention is not limited thereto. Various changes and modifications may be effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A clutch master cylinder comprising: the piston is positioned in the piston cavity;

the piston cavity part on one axial side of the piston is a hydraulic cavity, the cylinder body is provided with a first oil conveying part communicated with the hydraulic cavity, the peripheral surface of the piston is provided with an oil groove, and the cylinder body is provided with a second oil conveying part communicated with the oil groove;

the piston is characterized in that an oil passage is arranged in the piston and is communicated with the hydraulic cavity and the oil groove;

an on-off part is arranged in or outside the oil duct, and the on-off part is axially opposite to the piston;

the on-off part comprises a base body and an extension part, and the extension part extends from the base body to the opposite direction of the hydraulic cavity along the axial direction;

the on-off part is axially opposite to the piston through the base body, and at least part of the extending part is positioned in the oil duct and can slide along the oil duct;

under the action of oil pressure in the hydraulic cavity, the base body abuts against the piston to block the oil passage and the hydraulic cavity;

under the action of oil pressure in the oil passage, the base body is separated from the piston so that the oil passage is communicated with the hydraulic cavity;

the inner circumferential surface of the oil channel is provided with a first protruding part surrounding the extending part, the outer circumferential surface of the extending part is provided with a second protruding part, the first protruding part is located between the second protruding part and the base body, and the first protruding part and the second protruding part are provided with axial overlapping parts so as to prevent the on-off piece from moving outwards of the oil channel and separating from the oil channel.

2. The clutch master cylinder of claim 1, wherein the on-off member is disposed in the hydraulic chamber opposite the piston.

3. The clutch master cylinder according to claim 1, wherein at least one of an outer diameter of at least a portion of the base and an inner diameter of the first protrusion is connected by the extension portion, and is gradually reduced in a direction away from the hydraulic pressure chamber.

4. The clutch master cylinder of claim 3, wherein the first protrusion has an axial passage through which oil in the oil passage applies oil pressure to the outer circumferential surface of the extension portion to separate the base from the piston.

5. The clutch master cylinder of claim 4, wherein the axial passage is an axial through slot or an axial through hole.

6. The clutch master cylinder as claimed in claim 1, wherein the extension portion has a recess in an end surface of the piston facing away from the base in an axial direction.

7. The clutch master cylinder according to claim 1, wherein one of an inner peripheral surface of the oil passage and an outer peripheral surface of the extending portion has a groove and the other has a protrusion;

the projection is axially movable within the recess along the piston and abuts a corresponding side wall of the recess when the base is separated from the piston.

8. The clutch master cylinder of claim 1, wherein an outer diameter of the base is smaller than an inner diameter of the piston cavity.

9. The clutch master cylinder according to claim 1, wherein one of two surfaces of the base body that are axially opposed to the piston is provided with at least one annular groove that surrounds a central axis of the oil passage, and the other is provided with at least one annular protrusion that surrounds the central axis of the oil passage;

when the base body abuts against the piston, the protrusions are accommodated in the corresponding grooves and are in sealing arrangement with the grooves;

when the base body is separated from the piston, the protrusions are at least partially located outside the corresponding grooves so that the oil passages communicate with the hydraulic pressure chamber.

10. The clutch master cylinder of claim 1, wherein the piston comprises: the piston pin penetrates through the body part along the axial direction and is fixedly connected with the body part, the hydraulic cavity is positioned on one side of the piston pin, which is opposite to the body part, and the oil groove is formed in the outer peripheral surface of the body part;

the oil passage is arranged in the piston pin, and the piston is axially opposite to the on-off piece through the piston pin.

11. A clutch release mechanism comprising the clutch master cylinder according to any one of claims 1 to 10.