CN109281953B

CN109281953B - One-piece sealing device for clutch master cylinder and clutch master cylinder

Info

Publication number: CN109281953B
Application number: CN201710589346.3A
Authority: CN
Inventors: 徐志力; 瓦勒·瑞科特加罗; 刘鑫; 张岳林; 邹华进
Original assignee: Schaeffler Technologies AG and Co KG
Current assignee: Schaeffler Technologies AG and Co KG
Priority date: 2017-07-19
Filing date: 2017-07-19
Publication date: 2021-12-10
Anticipated expiration: 2037-07-19
Also published as: CN109281953A

Abstract

The invention provides a one-piece sealing device for a clutch master cylinder and the clutch master cylinder. The sealing device is used for sealing at least a pressure chamber at an opening of a hydraulic oil supplementing channel of the clutch master cylinder, which is close to the piston. The sealing device includes: a plurality of sealing portions; and a skeleton connecting the plurality of sealing portions. The seal device is generally annular in shape as a whole, and one or more passage holes that communicate the radially outer side and the radially inner side of the seal device are formed in the seal device. In the sealing device of the invention, the framework connects a plurality of sealing parts (sealing lips and/or sealing rings) to form a single-piece sealing device which has compact structure, is beneficial to the miniaturization of the clutch main cylinder, is beneficial to the simplification of the assembly of the clutch main cylinder and reduces the production cost.

Description

One-piece sealing device for clutch master cylinder and clutch master cylinder

Technical Field

The invention belongs to a clutch release system in vehicle engineering, and particularly relates to a sealing technology for sealing a piston of the clutch release system.

Background

Fig. 1 shows a partial axial section through a known clutch master cylinder 10. The clutch master cylinder 10 includes a housing 1, a piston 2, and a weld ring 3 between the housing 1 and the piston 2. A pressure chamber 11 and a hydraulic oil replenishment passage 12 are formed in the housing 1. The opening of the hydraulic oil replenishing passage 12 near the piston 2 is provided with a seal assembly 4. The seal assembly 4 is composed of a primary seal 41, a secondary seal 43, and an intermediate ring 42, which are independent of each other, arranged along the axial direction a of the clutch master cylinder 10. The primary seal 41 is responsible for sealing the pressure chamber 11 in the operating condition, the intermediate ring 42 supports the primary seal 41 and the secondary seal 43 is responsible for sealing in the pedal direction.

As shown in the axial cross-sectional view of fig. 1, in order to position the secondary seal 43, one end of the weld ring 3 near the seal assembly 4 is formed as an annular step portion 31 (large and small diameter portion), and the secondary seal 43 is positioned between the step portion 31 and the outer peripheral surface of the piston 2. An annular step portion 13 (large and small diameter portion) for positioning the intermediate ring 42 is also formed on the inner peripheral surface of the housing 1, and the axial position of the intermediate ring 42 is defined by the step portion 31 of the weld ring 3 and the step portion 13 of the housing 1. The housing 1 is also formed with an annular projection 14 for positioning the main seal 41, the annular projection 14 projecting into an annular recess of the main seal 41.

The seal assembly 4 is made up of three components, which wastes a lot of space, results in a larger housing diameter of the clutch master cylinder, and increases costs. The three-part seal assembly 4 also makes the assembly process more complicated.

Disclosure of Invention

In view of the problems in the prior art described above, an object of the present invention is to provide a one-piece sealing device for a clutch master cylinder and a clutch master cylinder including the same.

A one-piece sealing device for a clutch master cylinder for sealing at least a pressure chamber at an opening of a hydraulic oil replenishment passage of the clutch master cylinder near a piston, wherein the sealing device comprises:

a plurality of sealing portions; and

a skeleton connecting the plurality of sealing portions together,

wherein the seal device is substantially annular in shape as a whole, and one or more passage holes that communicate a radially outer side and a radially inner side of the seal device are formed in the seal device.

In at least one embodiment, the backbone has a generally U-shaped axial cross-section, and the seal extends away from the backbone.

In at least one embodiment, when the sealing device is installed between the housing and the piston of the clutch master cylinder, a first chamber is formed between an outer circumferential surface of the sealing device and an inner circumferential surface of the housing, and a second chamber is formed between the inner circumferential surface of the sealing device and an outer circumferential surface of the piston, the first chamber and the second chamber communicating with each other via the one or more passage holes.

In at least one embodiment, the one or more channel holes are formed in the scaffold.

In at least one embodiment, the one or more passage holes are formed in the backbone and the material forming the sealing portion.

In at least one embodiment, the sealing device comprises: an outer main seal portion and an inner main seal portion extending from one axial side of the frame; and an outer secondary seal portion and an inner secondary seal portion extending from the other axial side of the frame.

In at least one embodiment, base end portions of the outer main seal portion and the inner main seal portion are continuously bonded to each other to the framework, distal end portions of the outer main seal portion and the inner main seal portion are spaced apart from each other in a radial direction, and the outer sub seal portion and the inner sub seal portion are spaced apart from each other.

In at least one embodiment, when the sealing device is installed between the housing and the piston of the clutch master cylinder, in an axial cross section of the clutch master cylinder, an opening of the U-shaped structure of the skeleton is opened toward the weld ring of the clutch master cylinder, the outer secondary sealing portion forms a seal with the housing of the clutch master cylinder and an end face of the weld ring, and the inner secondary sealing portion forms a seal with the piston of the clutch master cylinder and an end face of the weld ring.

In at least one embodiment, the skeleton includes a base and first and second arms extending from the base toward the weld ring, and the one or more passage holes are formed in the first and second arms of the skeleton.

In at least one embodiment, in an axial cross section of the clutch master cylinder, a height of an opening of the U-shaped structure of the skeleton is greater than a height of a bottom of the U-shaped structure.

In at least one embodiment, the outer secondary seal comprises: a seal lip forming a seal with an inner peripheral surface of the housing; and the sealing ring forms sealing with the end face of the welding ring.

In at least one embodiment, the outer secondary seal portion includes a seal ring that forms a seal with both the inner peripheral surface of the housing and the end surface of the weld ring.

In at least one embodiment, the inner secondary seal comprises: a seal lip forming a seal with an outer peripheral surface of the piston; and the sealing ring forms sealing with the end face of the welding ring.

In at least one embodiment, when the sealing device is installed between the housing and the piston of the clutch master cylinder, in an axial cross section of the clutch master cylinder, an opening of the U-shaped structure of the skeleton is opened toward a radial outer side of the sealing device, the outer secondary sealing portion forms a seal with the housing of the clutch master cylinder, and the inner secondary sealing portion forms a seal with the piston of the clutch master cylinder.

In at least one embodiment, the skeleton includes a bottom portion and first and second arm portions projecting from the bottom portion toward a radially outer side of the seal device, the outer and inner primary seal portions extending away from the first arm portion, the second arm portion abutting against an end surface of a weld ring of the clutch master cylinder.

In at least one embodiment, the one or more channel holes are formed in the bottom of the skeletal frame.

In at least one embodiment, in an axial cross section of the clutch master cylinder, a connection portion of the bottom portion and the first arm portion is located radially outward of a connection portion of the skeleton and the second arm portion.

In at least one embodiment, the outer secondary seal portion is a seal ring located in a gap between an inner peripheral surface of the housing and an outer peripheral surface of the weld ring, and the inner secondary seal portion is a seal lip forming a seal with the outer peripheral surface of the piston.

In at least one embodiment, when the sealing device is installed between the housing and the piston of the clutch master cylinder, in an axial cross section of the clutch master cylinder, an opening of the U-shaped structure of the skeleton is opened toward a radial inner side of the sealing device, the outer secondary sealing portion forms a seal with the housing of the clutch master cylinder, and the inner secondary sealing portion forms a seal with the piston of the clutch master cylinder.

In at least one embodiment, the outer secondary seal portion is a seal ring having a D-shaped radial cross section, and the inner secondary seal portion is a seal lip extending obliquely toward the pressure chamber.

In at least one embodiment, the scaffold comprises: a bottom portion extending substantially along an axial direction of the sealing device; and a first arm portion and a second arm portion projecting from the bottom portion toward a radially inner side of the sealing device,

the one or more passage holes are formed in the bottom portion of the skeleton and a material forming the sealing portion.

In at least one embodiment, the material forming the sealing portion covers the second arm portion of the skeleton and forms a flat end surface of the other axial side of the sealing device.

In at least one embodiment, the inner main seal portion is a seal lip extending from the skeleton toward the pressure chamber and the piston, and the outer main seal portion is a seal lip extending from the skeleton toward the pressure chamber and a radially outer side of the seal device.

In at least one embodiment, substantially no material forming the seal is disposed within the interior of the skeleton.

In at least one embodiment, the material forming the seal surrounds the skeleton.

The invention also provides a clutch master cylinder comprising a sealing device according to the invention, which is arranged between the housing of the clutch master cylinder and the piston at the opening of the hydraulic oil supply channel close to the piston.

In at least one embodiment, an inner peripheral surface of the housing corresponding to the sealing means is formed as a flat surface, and an end surface of the weld ring of the clutch master cylinder facing the sealing means is also formed as a flat surface, in addition to the hydraulic oil replenishment passage.

In the sealing device of the invention, the framework connects a plurality of sealing parts (the sealing parts comprise the sealing lips and the sealing rings) together, thereby forming a single-piece sealing device which has compact structure, is beneficial to the miniaturization of the clutch main cylinder, is beneficial to the simplification of the assembly of the clutch main cylinder and reduces the production cost.

Drawings

Fig. 1 shows a partial axial section through a known clutch master cylinder.

Fig. 2A shows a partial axial cross-sectional view of a clutch master cylinder according to a first embodiment of the present invention.

Fig. 2B shows an enlarged view of a portion near the sealing device in fig. 2A.

Fig. 3A shows an enlarged partial axial cross-sectional view of a clutch master cylinder according to a second embodiment of the present invention.

Fig. 3B shows an axially sectioned perspective view of the sealing arrangement of the clutch master cylinder in fig. 3A.

Fig. 4 shows an enlarged partial axial cross-sectional view of a clutch master cylinder according to a third embodiment of the present invention.

Fig. 5 shows an axial cross-sectional view of a sealing arrangement of a clutch master cylinder according to a fourth embodiment of the invention.

Description of the reference numerals

1, a shell; 2, a piston; 3, welding a ring; 31 an annular step portion; 4, sealing the assembly; 41 a primary seal; 42 an intermediate ring; 43 secondary seals; 10 clutch master cylinder; 11 a pressure chamber; 12 hydraulic oil supplementing channel; 13 an annular step portion; 14 an annular protrusion; axial direction A; r is radial;

100 clutch master cylinder; 21 an annular step portion; 32 end faces; 401 outer primary seal lip; 402 an inboard primary seal lip; 403 outer secondary sealing lip; 404 an inner secondary sealing lip; 405. 407, 409, 410 outer sealing rings; 406 an inboard sealing ring; 420 a framework; 421 a first channel hole; 422 a second channel hole; 423 a third passage hole; 424 a fourth channel hole; 425 a bottom portion; 426 a first arm; 427 a second arm portion; 428 a distal end of the first arm; 429 a distal end of the second arm portion; a C1 first chamber; c2 second chamber.

Detailed Description

Exemplary embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood that the detailed description is intended only to teach one skilled in the art how to practice the invention, and is not intended to be exhaustive or to limit the scope of the invention.

The clutch master cylinder 100 of the present invention may have a structure similar to that of the clutch master cylinder 10 shown in fig. 1, components similar to those in fig. 1 are denoted by the same reference numerals, and repeated descriptions of these components are omitted.

The axial and radial directions of the clutch master cylinder 100 coincide with the axial and radial directions of the piston 2 and the axial and radial directions of the sealing means, and therefore, in the following description, the axial direction a may refer to the axial direction of the clutch master cylinder 100, the axial direction of the piston 2 and the axial direction of the sealing means, and the radial direction R may refer to the radial direction of the clutch master cylinder 100, the radial direction of the piston 2 and the radial direction of the sealing means. For the sake of simplicity, the pressure chamber 11 side is referred to as one axial side, and the weld ring 3 side is referred to as the other axial side.

First embodiment

Referring to fig. 2A, the clutch master cylinder 100 of the first embodiment includes a housing 1, a piston 2, and a weld ring 3. A pressure chamber 11 and a hydraulic oil replenishment passage 12 are formed in the housing 1. A one-piece sealing device is provided at the opening of the hydraulic oil supply passage 12 near the piston 2.

The sealing device is generally annular in shape as a whole. A sealing means is provided around the periphery of the piston 2 between the piston 2 and the housing 1. The axial position of the sealing device is defined by the annular projection 14 of the housing 1 projecting toward the other axial side and the end face 32 of the solder ring 3 facing toward one axial side.

Referring to fig. 2A and 2B, the sealing device includes a plurality of sealing portions (the sealing portion in the present application includes a sealing lip and a sealing ring) and a skeleton 420 connecting the plurality of sealing portions. The seal is bonded to a frame 420, the frame 420 forming one component of the seal.

The frame 420 may be an annular member having a substantially U-shaped axial cross section. Referring to the axial cross-section shown in fig. 2B, the bobbin 420 includes: a bottom portion 425 extending substantially in the radial direction R of the clutch master cylinder 100; a first arm 426 and a second arm 427 extending from the base 425 toward the end surface 32 of the solder ring 3. One or more first passage holes 421 and one or more second passage holes 422 are formed in the first arm 426 and the second arm 427, respectively. The frame 420 may be formed of a material such as metal or plastic (preferably rigid plastic), and the frame 420 may be made by casting or punching, if possible.

The hardness of the material forming the sealing portion is less than the hardness of the material forming the skeleton. The sealing portion may be formed of a material such as rubber and/or PTFE. For example, in the case where the sealing portion is formed of rubber, the sealing portion may be bonded to the frame 420 by vulcanization bonding. The seal portion includes an outer main seal lip 401, an inner main seal lip 402, an outer sub seal lip 403, and an inner sub seal lip 404. The seal portion may also include an outboard sealing ring 405 and an inboard sealing ring 406.

The outer main seal lip 401 extends from the bottom 425 of the skeleton 420 toward the pressure chamber 11 and the radial outside, thereby forming a contact seal with the inner peripheral surface of the housing 1. The inner main seal lip 402 extends from the bottom 425 of the frame 420 toward the pressure chamber 11 and the radially inner side, thereby forming a contact seal with the outer peripheral surface of the piston 2. The outer secondary seal lip 403 extends from the distal end portion 428 of the first arm 426 and forms a contact seal with the inner peripheral surface of the housing 1. The inner secondary sealing lip 404 extends from the distal end portion 429 of the second arm 427 and forms a contact seal with the outer peripheral surface of the piston 2. The outboard sealing ring 405 extends from the distal end 428 of the first arm 426 and forms a contact seal with the end face 32 of the weld ring 3. The inboard seal ring 406 extends from the distal end portion 429 of the second arm 427 and forms a contact seal with the end face 32 of the weld ring 3.

The distal end portion of the outer main seal lip 401 and the distal end portion of the inner main seal lip 402 are separated from each other in the radial direction R so that an annular recess into which the annular protrusion 14 of the housing 1 projects is formed therebetween, thereby defining the axial position of the seal device on one axial side. The outer sealing ring 405 and the inner sealing ring 406 are in contact with the end face 32 of the weld ring 3, defining the axial position of the sealing device on the other axial side.

The distal end portion 428 of the first arm portion 426 is crimped radially outward, so that the bonding area between the outer secondary seal lip 403 and the outer seal ring 405 and the distal end portion 428 is increased, and the bonding strength is improved. The distal end portions 429 of the second arm portions 427 are crimped radially inward, so that the bonding areas of the inner secondary seal lip 404 and the inner seal ring 406 to the distal end portions 429 are increased, and the bonding strength is improved.

The base end portion of the outer main seal lip 401 and the base end portion of the inner main seal lip 402 (portion on the bottom portion 425 side) are continuously bonded to each other to the bottom portion 425 of the frame 420, and therefore, the bonding strength of the outer main seal lip 401 and the inner main seal lip 402 to the frame 420 can be improved. The outer secondary seal lip 403 and the outer seal ring 405 may be continuous with each other, which may further prevent the outer secondary seal lip 403 and the outer seal ring 405 from peeling off the frame 420. Likewise, the inner secondary seal lip 404 and the inner seal ring 406 may be continuous with each other, which may further prevent the inner secondary seal lip 404 and the inner seal ring 406 from peeling away from the backbone 420.

Since the piston 2 will move in the axial direction a, the inner primary seal lip 402 and the inner secondary seal lip 404 can be regarded as dynamic seal lips. The inner main seal lip 402, which is in contact with the piston 2, serves to seal the hydraulic oil in the pressure chamber 11. The inner secondary seal lip 404 and the inner primary seal lip 402 are in contact with the piston 2, so that a second chamber C2 for storing hydraulic oil is formed between the inner secondary seal lip 404, the inner primary seal lip 402, the second arm portion 427, and the piston 2, and the hydraulic oil in the second chamber C2 is used for lubricating the inner secondary seal lip 404 and the inner primary seal lip 402. The second chamber C2 communicates with the second passage hole 422.

Since the seal device is stationary with respect to the housing 1 and the weld ring 3, the outer primary seal lip 401, the outer secondary seal lip 403, the outer seal ring 405, and the inner seal ring 406 can be regarded as static seal portions. The outer main seal lip 401, which is in contact with the housing 1, serves to seal the hydraulic oil in the pressure chamber 11. The outside primary seal lip 401 and the outside secondary seal lip 403 are in contact with the housing 1, so that a first chamber C1 is formed between the outside primary seal lip 401, the outside secondary seal lip 403, the first arm 426, and the housing 1, the first chamber C1 communicating with the first passage hole 421 and the hydraulic oil replenishment passage 12.

The hydraulic oil from the hydraulic oil replenishment passage 12 can flow into the second chamber C2 via the first chamber C1, the first passage hole 421, the annular space between the first arm 426 and the second arm 427, the second passage hole 422. An annular step portion 21 is formed at one end of the piston main body of the piston 2 facing the pressure chamber 11. When the piston 2 moves in the axial direction a so that the inner main seal lip 402 enters the annular step portion 21, the hydraulic oil in the second chamber C2 can flow into the pressure chamber 11.

The outer seal ring 405 and the inner seal ring 406, which are in contact with the end face 32 of the weld ring 3, serve as static seals to prevent hydraulic oil from leaking out.

The seal of this embodiment may integrate the dynamic seal lip, the static seal lip and the static seal ring (static seal) into one component (the skeleton 420), in such a way that the three components of the known seal assembly of fig. 1 are replaced by this one-piece seal, which saves a lot of space and costs and also reduces the steps of the assembly process.

The backbone 420 provides support for each seal, and at high pressures, forces are transferred from the seal to the weld ring 3, and the backbone 420 helps support the seal. The passage hole communicates the radially outer side and the radially inner side of the one-piece sealing device and allows compensation of hydraulic oil.

In this embodiment, the end of the end face 32 of the weld ring 3 does not have a step (compare with step 31 in fig. 1), nor does the inner peripheral surface of the housing 1 corresponding to the sealing device have to have a step (compare with step 13 in fig. 1). Thus, the structure of the weld ring 3 and the housing 1 is simplified, and the diameter of the clutch master cylinder is reduced. The present embodiment thus provides a compact seal device for a clutch master cylinder.

The bobbin 420 is formed to have a substantially U-shaped axial cross section. The U-shaped opening configuration allows the distance between the two arms 426 and 427 (and particularly the distance between the distal ends 428 and 429) to be adjusted or varied as appropriate, increasing the flexibility of the seal. Sealing portions are provided at the distal end portions 428 of the first arm portions 426 and the distal end portions 429 of the second arm portions 427, respectively, and the sealing portions provided at the distal end portions 428 and the sealing portions provided at the distal end portions 429 are separated from each other, so that the amount of material (e.g., rubber and/or PTFE, etc.) used for forming the sealing portions can be reduced, and the production cost can be reduced. The material for forming the sealing portion is not substantially provided inside the frame 420, and thus, the amount of the material can be reduced.

Referring to fig. 1, the hydraulic oil replenishment passage 12 is opened toward the seal assembly 4 and the weld ring 3 at the annular step portion 31 of the weld ring 3, and thus hydraulic oil is liable to leak from a gap between the inner peripheral surface of the housing 1 and the outer peripheral surface of the annular step portion 31 toward the right side in fig. 1. Thus, the weld ring 3 is required to be welded to the housing 1 to prevent the hydraulic oil from leaking to the outside of the clutch master cylinder 10.

In the present embodiment, the outer secondary seal lip 403 and the outer seal ring 405 form contact seals with the inner peripheral surface of the housing 1 and the end surface 32 of the weld ring on the other axial side of the hydraulic oil replenishment passage 12 near the opening of the piston 2, so that leakage of hydraulic oil from between the housing 1 and the weld ring 3 to the outside of the clutch master cylinder 100 can be effectively prevented, and welding between the housing 1 and the weld ring 3 can be omitted. In the present embodiment, the housing 1 and the solder ring 3 may be snapped together using elastic claws and holes or recesses using a snap-in structure. In this way, the mounting process of the housing 1 and the solder ring 3 is simplified.

As can also be seen from fig. 2A and 2B, the outer main seal lip 401 forms a contact seal with the inner peripheral surface of the housing 1 on the axial side of the hydraulic oil replenishment passage 12 near the opening of the piston 2. The diameter or width of the hydraulic oil replenishment passage 12 is reduced toward the opening side of the hydraulic oil replenishment passage 12 near the piston 2, and therefore, the sealing device needs only to have a small axial dimension to seal the axial both sides of the hydraulic oil replenishment passage 12 near the opening of the piston 2, which is advantageous in terms of the miniaturization of the sealing device.

Second oneDetailed description of the preferred embodiments

A second embodiment of the present invention will be described with reference to fig. 3A and 3B, and the same or similar components as those of the first embodiment will be denoted by the same reference numerals, and redundant description thereof will be omitted. The following mainly explains differences of the second embodiment from the first embodiment.

Since the hydraulic oil in the first chamber C1 has almost no pressure, the outer side seal ring 407 may be used in the second embodiment instead of the outer side secondary seal lip 403 and the outer side seal ring 405 in the first embodiment. This outer seal ring 407 extends radially outward from the distal end portion 428 of the first arm portion 426, and the outer seal ring 407 includes a portion on one axial side (i.e., the left side in fig. 3A) of the distal end portion 428 and a portion on the other axial side (i.e., the right side in fig. 3A) in the axial direction a. In this way, the outer seal ring 407 forms a contact seal with the inner peripheral surface of the housing 1, and at the same time, the outer seal ring 407 also forms a contact seal with the end surface 32 of the weld ring 3, thereby preventing the hydraulic oil from leaking from the weld ring 3.

Alternatively, all of the other sealing lips except the inboard primary sealing lip 402 can be replaced by sealing rings.

It is generally understood that the sealing effect of the seal lip has directionality, and the directionality of the sealing effect of the seal ring is substantially smaller than the directionality of the sealing effect of the seal lip, or the sealing effect of the seal ring has no directionality. For example, in the case of the inner main seal lip 402, the inner main seal lip 402 extends from the bottom 425 of the frame 420 toward the piston 2 side (radially inner side) and the pressure chamber 11 side (axial side), and thus the pressure chamber 11 side is the sealed side of the inner main seal lip 402. In other words, the hydraulic oil can easily flow from the second chamber C2 side to the pressure chamber 11 side through the inner main seal lip 402 at a pressure at which the hydraulic oil is less likely to flow from the pressure chamber 11 side to the second chamber C2 side through the inner main seal lip 402. And the sealing effect of the seal ring 407 on both axial sides of the seal ring 407 is substantially equal.

The second embodiment can obtain effects similar to those of the first embodiment. In addition, since the outer seal ring 407 is used instead of the outer secondary seal lip 403 and the outer seal ring 405 in the first embodiment, the structure of the sealing device is simplified, and the production cost can be reduced.

Third embodiment

A third embodiment of the present invention will be described with reference to fig. 4, where the same or similar components as those of the second embodiment are denoted by the same reference numerals, and repeated description thereof will be omitted. The following mainly explains differences of the third embodiment from the second embodiment.

Referring to fig. 4, the sealing device includes a plurality of sealing portions and a frame 420 connecting the plurality of sealing portions. The frame 420 may be an annular member having a substantially U-shaped axial cross section. Unlike the case where the bobbin 420 is opened toward the end surface 32 in the first and second embodiments, the substantially U-shaped structure of the axial cross section of the bobbin 420 is opened toward the radial outside, that is, toward the inner circumferential surface of the housing 1 in the third embodiment. The bobbin 420 includes: a bottom portion 425 extending substantially along the axial direction a of the clutch master cylinder 100; a first arm 426 and a second arm 427 extending radially outward from the bottom 425. One or more third passage holes 423 are formed at the bottom 425.

The seal portion includes an outer main seal lip 401, an inner main seal lip 402, an outer seal ring 409, and an inner sub seal lip 404.

The outer main seal lip 401 extends from the distal end portion 428 of the first arm portion 426 toward the pressure chamber 11 side and the radial outside, thereby forming a contact seal with the inner peripheral surface of the housing 1. The inner main seal lip 402 extends from one corner between the first arm portion 426 and the bottom portion 425 toward the pressure chamber 11 side and the radial inside, thereby forming a contact seal with the outer peripheral surface of the piston 2. The outer sealing ring 409 extends from the distal end portion 429 of the second arm 427 and forms a contact seal with the inner peripheral surface of the housing 1. The inner secondary seal lip 404 extends from the vicinity of the other corner of the bottom 425 of the frame 420 and forms a contact seal with the outer peripheral surface of the piston 2. The annular projection 14 of the housing 1 projects into the annular recess between the outer main sealing lip 401 and the inner main sealing lip 402, so that the axial position of the sealing device is defined on one axial side. The second arm 427 abuts against the end face 32 of the weld ring 3, thereby defining the axial position of the seal device on the other axial side.

The distal end portion 428 of the first arm portion 426 is crimped to one axial side, so that the bonding area between the outer main seal lip 401 and the distal end portion 428 is increased, and the bonding strength is improved. The distal end portions 429 of the second arm portions 427 are crimped to the other axial side, so that the bonding area between the outer seal ring 409 and the distal end portions 429 is increased, and the bonding strength is improved.

A first chamber C1 is formed between the skeleton 420 and the inner peripheral surface of the housing 1, the first chamber C1 communicating with the hydraulic oil replenishment passage 12. A second chamber C2 for storing hydraulic oil is formed between the inner secondary seal lip 404, the inner primary seal lip 402, the bottom 425 of the frame 420, and the piston 2, and the hydraulic oil in the second chamber C2 is used for lubricating the inner secondary seal lip 404 and the inner primary seal lip 402. The second chamber C2 communicates with the third passage hole 423.

In the present embodiment, the bottom portion 425 is provided so as to be inclined with respect to the axial direction a so as to be a large distance from the outer peripheral surface of the piston 2 on the first arm portion 426 side and a small distance from the outer peripheral surface of the piston 2 on the second arm portion 427 side. With this structure, on the one hand, formation of the above-described second chamber C2 is facilitated, and on the other hand, the inner primary seal lip 402 extends obliquely toward the piston 2 side, achieving a sealing effect, and the distance of the corner between the bottom portion 425 and the second arm portion 427 from the outer peripheral surface of the piston 2 can be reduced, reducing the length of the inner secondary seal lip 404.

The hydraulic oil from the hydraulic oil replenishment passage 12 can flow into the pressure chamber 11 via the first chamber C1, the third passage hole 423, the second chamber C2, and the annular step portion 21.

The third embodiment can obtain effects similar to those of the first and second embodiments, but can reduce the number of passage holes in the frame 420 and the number of seal portions, reducing the cost of the sealing device.

Fourth embodiment

A fourth embodiment of the present invention will be described with reference to fig. 5, in which the same or similar components as those of the first embodiment are denoted by the same reference numerals, and redundant description thereof will be omitted. The following mainly explains differences of the fourth embodiment from the first embodiment.

The sealing device of the present embodiment may be used for the clutch master cylinder in the first embodiment. The seal is also a one-piece seal that includes a skeleton 420 and a plurality of seals. The skeleton 420 may be completely surrounded by the material forming the sealing portion. The sealing device of the present embodiment may be formed by over-molding.

The frame 420 may be an annular member having a substantially U-shaped axial cross section. In an axial cross section of the bobbin 420, the bobbin 420 includes: a base 425 extending generally along the axial direction a; a first arm 426 and a second arm 427 extending from the bottom 425 toward the radial inside.

The seal portion includes an outer main seal lip 401, an inner main seal lip 402, an outer seal ring 410, and an inner sub seal lip 404.

The outer main seal lip 401 extends from the frame 420 toward the pressure chamber 11 side, and forms a seal with the inner peripheral surface of the housing 1. The inner main seal lip 402 extends from the skeleton 420 toward the pressure chamber 11 side and the radial inside, thereby forming a contact seal with the outer peripheral surface of the piston 2. The outer seal ring 410 extends radially outward from the frame 420 and forms a contact seal with the inner circumferential surface of the housing 1. The inner secondary seal lip 404 extends from the skeleton 420 toward the pressure chamber 11 side and the radial inside and forms a contact seal with the outer peripheral surface of the piston 2.

The distal end portion of the outer main seal lip 401 and the distal end portion of the inner main seal lip 402 are separated in the radial direction R so as to form an annular recess therebetween, into which the annular protrusion 14 of the housing 1 projects, thereby defining the axial position of the seal device on one axial side. The end face of the other axial side of the seal device is formed as a substantially flat face which is in contact with the end face 32 of the weld ring 3, thereby defining the axial position of the seal device on the other axial side.

As shown in the axial cross section in fig. 5, the outer seal ring 410 is formed into a D-shaped seal portion having an arcuate outer surface in the radial direction. Since the outer seal ring 410 protrudes radially outward beyond the other portions of the seal device, a first chamber C1 similar to the first chamber C1 in the first embodiment may be formed between the outer peripheral surface of the seal device, the inner peripheral surface of the housing 1, and the outer seal ring 410. The first chamber C1 communicates with the hydraulic oil replenishment passage 12. In addition, a plurality of fourth passage holes 424 penetrating the sealing device in the radial direction are formed in the sealing device. The fourth passage hole 424 communicates with the first chamber C1.

The hydraulic oil from the hydraulic oil replenishment passage 12 can flow into the pressure chamber 11 via the first chamber C1, the fourth passage hole 424, the second chamber C2, and the annular step portion 21.

This fourth embodiment can obtain effects similar to those of the first to third embodiments described above. In this fourth embodiment, since the material forming the seal portion completely surrounds the frame 420, the radial thickness of the entire seal device can be set smaller, thereby further reducing the diameter of the clutch master cylinder. In addition, the outer shape of the sealing device of the present embodiment is simpler, and therefore the sealing device can be molded with a simpler mold.

It should be understood that the above embodiments are only exemplary and are not intended to limit the present invention. Various modifications and alterations of the above-described embodiments may be made by those skilled in the art in light of the teachings of the present invention without departing from the scope thereof.

(1) In the above embodiment, the bobbin 420 has a substantially U-shaped axial cross section, however, the present invention is not limited thereto. For example, the backbone 420 may have a generally rectangular axial cross-section.

(2) The opening direction of the U-shaped structure of the bobbin 420 is not limited to the above-described embodiment. For example, in the first and second embodiments, the U-shaped structure may be provided so as to be open to one side in the axial direction (the pressure chamber 11 side). However, in the structures of the first and second embodiments, the inner main seal lip 402 extends from the bottom portion 425, and the bonding area of the inner main seal lip 402 mainly used for sealing the pressure chamber 11 can be increased, thereby improving the bonding strength.

For example, in the third embodiment, the U-shaped structure may be provided so as to open radially inward, and in the fourth embodiment, the U-shaped structure may be provided so as to open radially outward.

(3) In the fourth embodiment, the material forming the sealing portion does not necessarily surround the entire skeleton 420. For example, the radially outer side of the backbone 420 may be entirely or partially free of material forming the seal.

(4) The position of the passage hole is not limited to the position shown in the above-described embodiment. For example, one or more passage holes may be formed in the material forming the seal portion (e.g., the base end portions of the outer main seal lip 401 and the inner main seal lip 402). However, in contrast, forming the passage holes in the frame 420 is easier and easier, and the production cost can be reduced.

(5) In the present application, the fact that the inner circumferential surface of the housing 1 corresponding to the sealing means is formed as a flat surface means that no step (i.e., a large diameter portion) is formed at a portion of the housing 1 that contacts or faces the sealing means. The flat surface is linear in an axial cross section of the clutch master cylinder.

In the present application, the fact that the end face 32 of the weld ring 3 of the clutch master cylinder facing the sealing device is formed as a flat face means that the end face 32 of the weld ring 3 facing the sealing device has no step between the housing 1 and the piston 2, and the flat face is linear in the axial cross section of the clutch master cylinder.

Claims

1. A one-piece sealing device for a clutch master cylinder for sealing at least a pressure chamber at an opening of a hydraulic oil replenishment passage of the clutch master cylinder near a piston, the sealing device comprising:

a plurality of sealing portions; and

a skeleton connecting the plurality of sealing portions together,

wherein the seal device is substantially annular in shape as a whole, and one or more passage holes that communicate a radially outer side and a radially inner side of the seal device are formed in the seal device; the frame has a generally U-shaped axial cross-section, and the seal extends away from the frame.

2. The sealing device according to claim 1, wherein when the sealing device is installed between a housing of the clutch master cylinder and a piston, a first chamber is formed between an outer peripheral surface of the sealing device and an inner peripheral surface of the housing, and a second chamber is formed between the inner peripheral surface of the sealing device and an outer peripheral surface of the piston, the first chamber and the second chamber communicating with each other via the one or more passage holes.

3. The sealing device of claim 1, wherein the one or more passage holes are formed in the backbone.

4. The sealing device of claim 1, wherein the one or more passage holes are formed in the backbone and the material forming the sealing portion.

5. The sealing device of claim 1, wherein the sealing device comprises: an outer main seal portion and an inner main seal portion extending from one axial side of the frame; and an outer secondary seal portion and an inner secondary seal portion extending from the other axial side of the frame.

6. The sealing device according to claim 5, wherein base end portions of the outer main sealing portion and the inner main sealing portion are continuously bonded to each other to the skeleton, distal end portions of the outer main sealing portion and the inner main sealing portion are separated from each other in a radial direction, and the outer sub sealing portion and the inner sub sealing portion are separated from each other.

7. The sealing device according to claim 5, wherein when the sealing device is installed between the housing and the piston of the clutch master cylinder, in an axial cross section of the clutch master cylinder, an opening of the U-shaped structure of the skeleton is opened toward the weld ring of the clutch master cylinder, the outer secondary sealing portion forms a seal with the housing of the clutch master cylinder and an end face of the weld ring, and the inner secondary sealing portion forms a seal with the piston of the clutch master cylinder and an end face of the weld ring.

8. The sealing device of claim 7, wherein the skeleton includes a base and first and second arms extending from the base toward the weld ring, the one or more passage holes being formed in the first and second arms of the skeleton.

9. The sealing arrangement of claim 7, wherein in an axial cross-section of the clutch master cylinder, a height of an opening of the U-shaped structure of the skeleton is greater than a height of a bottom of the U-shaped structure.

10. The sealing device of claim 7, wherein the outboard secondary seal comprises: a seal lip forming a seal with an inner peripheral surface of the housing; and the sealing ring forms sealing with the end face of the welding ring.

11. The seal arrangement of claim 7, wherein the outer secondary seal includes a seal ring that forms a seal with both the inner circumferential surface of the housing and the end surface of the weld ring.

12. The sealing device of claim 7, wherein the inboard secondary seal comprises: a seal lip forming a seal with an outer peripheral surface of the piston; and the sealing ring forms sealing with the end face of the welding ring.

13. The sealing device of claim 5, wherein, when the sealing device is installed between the housing and the piston of the clutch master cylinder, in an axial cross section of the clutch master cylinder, an opening of the U-shaped structure of the skeleton is opened toward a radial outer side of the sealing device, the outer secondary sealing portion forms a seal with the housing of the clutch master cylinder, and the inner secondary sealing portion forms a seal with the piston of the clutch master cylinder.

14. The seal of claim 13, wherein the skeleton includes a base and first and second arms projecting from the base radially outward of the seal, the outer and inner primary seals extending away from the first arm, the second arm abutting an end face of a weld ring of the clutch master cylinder.

15. The sealing device of claim 14, wherein the one or more channel holes are formed in the bottom of the skeletal frame.

16. The sealing device according to claim 14, wherein a connecting portion of the bottom portion and the first arm portion is located radially outward of a connecting portion of the skeleton and the second arm portion in an axial cross section of the clutch master cylinder.

17. The sealing device according to claim 14, wherein the outer secondary sealing portion is a seal ring located in a gap between an inner peripheral surface of the housing and an outer peripheral surface of the weld ring, and the inner secondary sealing portion is a seal lip forming a seal with an outer peripheral surface of the piston.

18. The sealing device of claim 5, wherein, when the sealing device is installed between the housing and the piston of the clutch master cylinder, in an axial cross section of the clutch master cylinder, an opening of the U-shaped structure of the skeleton is opened toward a radial inner side of the sealing device, the outer secondary sealing portion forms a seal with the housing of the clutch master cylinder, and the inner secondary sealing portion forms a seal with the piston of the clutch master cylinder.

19. The sealing device according to claim 18, wherein the outer secondary sealing portion is a seal ring having a D-shaped radial cross section, and the inner secondary sealing portion is a seal lip extending obliquely toward the pressure chamber.

20. The sealing device of claim 18, wherein the backbone comprises: a bottom portion extending substantially along an axial direction of the sealing device; and a first arm portion and a second arm portion projecting from the bottom portion toward a radially inner side of the sealing device,

21. The seal of claim 18, wherein the material forming the seal portion wraps around the second arm portion of the armature and forms a flat end surface on the other axial side of the seal.

22. The seal arrangement of claim 5, wherein the inner primary seal is a seal lip extending from the skeleton towards the pressure chamber and the piston, and the outer primary seal is a seal lip extending from the skeleton towards the pressure chamber and a radially outer side of the seal arrangement.

23. The sealing device of any one of claims 1 to 22, wherein no material forming the sealing portion is provided inside the skeleton.

24. The sealing device of any one of claims 1 to 22, wherein the material forming the sealing portion surrounds the skeleton.

25. A clutch master cylinder, characterized in that it comprises a sealing device according to any one of claims 1 to 24, which is provided between the housing of the clutch master cylinder and the piston at the opening of the hydraulic oil replenishment passage close to the piston.

26. The clutch master cylinder according to claim 25, wherein an inner peripheral surface of the housing corresponding to the sealing means is formed as a flat surface, and an end surface of the weld ring of the clutch master cylinder facing the sealing means is also formed as a flat surface, in addition to the hydraulic oil replenishment passage.