JP2003194100A - Pressure generating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the structure of a seal member capable of preventing the generation of a cut of the seal member into a sliding member and restricting the sliding resistance of the sliding member when the sliding member moves inside of a pressure chamber. <P>SOLUTION: In this pressure generating device 1, the seal member 4 is arranged between a pressure chamber 10 formed inside of a housing and a port 11 communicating with the pressure chamber 10, and a piston 6 moves in the pressure chamber to cut the communication between the pressure chamber 10 and the port 11 with the seal member 4 having a base part 4a, and inner peripheral rib 4b and an outer peripheral rib 4c. Shape of the seal member 4 is formed into a shape having a tapered surface 4d to be widened outward in the radial direction at a rear end of the inner peripheral rib 4b to be slid for contact with the piston 6 within a range of a width of the base part 4a in the axial direction, in which the piston 6 slides. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure generator for generating pressure outside by varying the volume of a pressure chamber by the movement of a sliding member, and in particular, the sliding member slides in the pressure chamber. In the case of performing the above, the present invention relates to the structure of the seal member that protects the seal member that connects / blocks between the pressure chamber and the port to which the fluid is supplied.

[0002]

2. Description of the Related Art Conventionally, a pressure generator has a pressure chamber formed in a housing, a port communicating with the pressure chamber, a base portion, an outer peripheral rib extending from the base portion, and a sliding member extending from the base portion. A seal member having an inner peripheral rib slidably contacting with the pressure chamber and interposed between the pressure chamber and the port; and a sliding member for sliding the pressure chamber in one direction to vary the volume of the pressure chamber. There is known a pressure generating device that raises the pressure chamber to a high pressure by blocking the pressure chamber and the port by a seal member due to the movement of the sliding member, and such a pressure generating device includes, for example, a master cylinder. It has been known.

In a master cylinder of a vehicle, a through hole is formed in a radial direction on a peripheral surface of a sliding member (piston), a pressure chamber communicates with a reservoir through the through hole, and the piston moves inward of the pressure chamber. Then, the through hole of the piston passes through the annular seal to cut off the communication between the pressure chamber and the reservoir, and the piston is moved in the direction in which the volume of the pressure chamber becomes smaller, so that the fluid in the pressure chamber is transferred to the operated cylinder. A type of pumping is known.

For example, in the master cylinder disclosed in Japanese Utility Model Laid-Open No. 4-39090, when the through hole formed in the radial direction of the piston reaches the annular seal member, the fluid increased in pressure in the pressure chamber acts as the piston. In order to prevent the fluid from flowing out from the through hole to the reservoir by pushing the base part of the annular cup seal, which is the sliding surface of the A seal member having an annular protrusion is used. In the master cylinder disclosed in this publication, a seal member having a shape shown in FIG. 8A is used to seal the passage communicating with the oil reservoir with the pressure chamber.

In this case, the piston has moved and the outer peripheral surface of the piston has passed the seal member ((b) of FIG. 8).
In the state shown in (1), a state may occur in which the annular protrusion protruding to the inner diameter side of the seal member enters the through hole. This is because, as shown in FIG. 8C, the pressure contact force from the seal member to the piston is increased due to the elastic force of the annular protrusion toward the inner diameter side, which increases the pressure contact force at the portion where the annular protrusion is formed. caused by.

[0006]

However, in the structure of the seal member disclosed in the above publication, the annular projection is formed to increase the pressure contact force of the annular seal member with respect to the piston. When moving and sliding, the sliding resistance increases, making it difficult for the piston to slide smoothly along the inner wall of the pressure chamber. As a result, defects due to poor return of the piston (for example,
Brake drag occurs in the master cylinder of the braking device. Further, clutch slippage and the like may occur in the clutch master cylinder. Furthermore, when the position of the through hole passes through the annular projection due to the movement of the piston, the annular projection is caught in the through hole and is damaged, which causes abnormal noise accompanying the movement of the piston. .

Therefore, the present invention has been made in view of the above problems, and prevents the seal member from being caught in the sliding member when the sliding member moves in the pressure chamber, and A technical problem is to provide a structure of a seal member that reduces the sliding resistance of the sliding member.

[0008]

The technical means taken to solve the above-mentioned problems include a pressure chamber formed in a housing, a port communicating with the pressure chamber, a base portion and an extension from the base portion. A seal member interposed between the pressure chamber and the port, and an inner peripheral rib extending from the base portion and in sliding contact with the sliding member; And a sliding member that moves to change the volume of the pressure chamber, and the pressure of the pressure chamber is increased by the movement of the sliding member to block the pressure chamber and the port from each other by the sealing member. In the pressure generator, the seal member has a taper surface on the inner peripheral rib that widens toward the outer diameter side within the width range of the base portion in the sliding direction in which the sliding member slides. It was a matter of course.

According to the above-mentioned means, the seal member has, on the inner peripheral rib, a tapered surface that widens toward the outer diameter side within the width range of the base portion in the sliding direction in which the sliding member slides. . As a result, when the sliding member slides, the pressure contact force against the sliding member does not act on the inner diameter side at the tapered surface, and the occurrence of the sealing member being caught in the sliding member is suppressed.

In this case, when the uneven portion is formed on the sliding contact surface of the inner peripheral rib with the sliding member, the contact area on the sliding contact surface with the sliding member is smaller than that in the case where the uneven portion is not formed. Therefore, the sliding resistance between the inner peripheral rib and the sliding member is reduced.

Further, when the oil film layer is formed on the uneven portion, the oil film layer further reduces the sliding resistance when the sliding member moves.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. The pressure generator in this embodiment is a clutch master cylinder (hereinafter referred to as a master cylinder) 1 of a vehicle that engages / disengages a clutch.
Will be described as an example. However, the present invention is not limited to this as long as the volume of the pressure chamber can be changed by the movement of the sliding member and pressure is supplied to the external device. In describing the present embodiment, in FIG. 1, the housing side is the front side, the rod side is the rear side, the piston moving direction (the direction moving forward and backward) is the axial direction, the output port side is the upper side, and the opposite side. Is defined as the lower part.

FIG. 1 is a sectional view of a master cylinder 1 which is a pressure generator. The master cylinder 1 has a housing 2 made of resin. The housing 2 has a hollow bottomed cylindrical shape with an opening 2g at the rear, and a pressure chamber 10 formed in a liquid-tight manner by a piston 6 described later is provided inside the hollow. The opening 2g at the rear of the pressure chamber of the housing 2 has a large diameter stepwise. Also, the housing 2
The port portion 2a projects toward the upper part. There is provided a port (output port) 8 through which the hydraulic oil pressurized by the pressure chamber 10 is discharged. Further, the housing 2 is provided with a recess 2b above the stepped rear portion,
The recess 2b serves as a port (input port) 11 into which hydraulic oil is introduced from the reservoir. At the rear of the housing 2, there is provided a flange portion 2c when the master cylinder 1 is attached to the vehicle by a fastening member.

The port 8 communicates with the pressure chamber 10 in front of the housing 2 through a communication hole 2aa extending in the radial direction, and is connected to a clutch operating cylinder (not shown). In this master cylinder 1, a clutch (not shown) can be disengaged depending on the pressure state of the hydraulic oil supplied from the port 8. On the other hand, the port 11 formed in the recess 2b communicates with the pressure chamber 10 through a communication hole 2ba that extends in the radial direction. A union 20 made of resin is fixed to the housing 2 in the recess 2b by ultrasonic welding. The union 20 has a through hole 20 inside.
a and a reservoir port 9 that is slightly larger than the inner diameters of the through holes 20a are provided and connected to a reservoir (not shown) capable of storing hydraulic oil therein. As a result, the hydraulic oil stored in the reservoir is passed through the through hole 20 of the union 20.
a, through the reservoir port 9 and port 11 in the recess 2b
Can be guided to the pressure chamber 10 inside the housing through the communication hole 2ba.

In the housing 2, in front of the communication hole 2ba,
An annular seal member 4 described later is provided, and an annular seal member 5 is provided behind it. The seal members 4 and 5 are arranged on the outer circumference of a cylindrical piston 6 that is arranged slidably in the axial direction with respect to the pressure chamber 10.

In the state shown in FIG. 1, the piston 6 is
The front side is supported by a hollow trapezoidal support ring 12 having a step in the radial direction, and the rear side is supported by a bottomed cylindrical guide sleeve 3. The guide sleeve 3 is arranged coaxially with the inner diameters of the piston 6 and the pressure chamber 10 so that it can slide on the outer peripheral surface of the piston 6. A support ring 12 is provided between the housing 2 and the guide sleeve 3, and the support ring 12 is also arranged coaxially with the piston 6. In this state, with respect to the opening 2g of the housing 2, the inner diameter of the housing 2 and the outer diameter of the support ring 12 are sealed by the seal member 24 made of an annular rubber fitted to the step portion 12b of the outer shape of the support ring 12. . Further, between the housing 2 and the support ring 12, fixing pins 13 are inserted into holes provided at several positions of the housing 2 and grooves provided on the outer diameter of the support ring 12, and the fixing pins 13 allow the housing 2 and the support ring 12 to be supported. The ring 12 is fixed integrally.

A groove portion 12a is provided in a part of the inner diameter of the rear step portion of the support ring 12, and a claw portion 3a formed integrally with the guide sleeve 3 from the front side to the rear side of the guide sleeve 3 is provided in the groove portion 12a. Fit in. By the fitting of the groove 12a of the claw 3a, the support ring 12 restricts the movement of the guide sleeve 3 in the axial direction.
Therefore, since the support ring 12 is fixed to the housing 2 by the fixing pin 13 and the guide sleeve 3 is fixed by the claw portion 3a, the support ring 12 and the guide sleeve 3 are integrally fixed to the housing 2. It will be one.

On the other hand, on the rear end surface of the housing 2, a dust boot 22 having a convex portion protruding rearward is provided coaxially with the piston 6 so as to cover the opening 2g of the housing 2. The dust boot 22 has a flange portion 22a on the front side, and when the master cylinder 1 is fixed to the vehicle body from within the engine room, the flange portion 2c of the housing 2 is provided.
From behind, the flange portion 22a of the dust boot 22 is sandwiched and fixed to the vehicle body. As a result, the master cylinder 1 is fixed to the vehicle.

The piston 6 which varies the volume of the pressure chamber 10 and slides in the front-back direction shown in FIG. 1 is provided with a recess 6a at the front end thereof. In the radial direction of the recess 6a, a communication hole 6 having a small diameter that communicates from the outer diameter of the piston into the recess.
A plurality of (for example, four) b are provided at equal intervals in the circumferential direction. Due to this small-diameter communication hole 6b, at the initial position of the piston 6, the pressure chamber 10 and the communication hole 2ba communicate with each other through a plurality of communication holes 12c provided in the radial direction of the support ring 12. Residual pressure does not occur in the pressure chamber in the state shown in FIG. 1 in which external force is not applied to 7.

A recess 6e is provided on the rear end surface of the piston 6 in the axial direction. The bottom of the recess 6e has a mortar shape 6
The rod 7 is arranged in a state of being c, and the hemispherical tip 7a of the rod 7 is in contact therewith. A flange portion 7b is provided behind the hemispherical tip 7a, and a rear end surface of the flange portion 7b is provided in a groove portion 6 provided in a concave portion of the piston 6.
The rod 7 is regulated by the snap ring 23 fitted in d so that the rod 7 does not come off in the axial direction with respect to the piston 6.

In this case, the rod 7 is the guide sleeve 3
3b and dust boot 22 provided in the rear end face of the
The rod 7 is inserted into a hole 22b provided at the rear end face of the rod 7, and the rod 7 can swing about the flange portion 7b by a predetermined angle.

In such a structure, the seal member 4 functions to connect the communication hole 2ba and the communication hole 6b having a small diameter in the initial state shown in FIG. When the piston 6 is stepped on and the external force based on the step is applied to the rod 7 to move the piston 6 forward to reduce the volume of the pressure chamber 10, the communication hole 2b
It has a function of blocking the communication between a and the pressure chamber 10. Further, the seal member 5 has a function of blocking the hydraulic oil from flowing out from the pressure chamber 10 behind the piston 6 and between the support ring 12 and the guide sleeve 3.

The pressure chamber 10 will be described. On the other hand, the pressure chamber 10 of the housing 1 made of resin extends axially on the inner wall of the pressure chamber 10 and serves as a guide function in the pressure chamber 10 when the piston 6 slides. During the air bleeding operation in the initial stage of operation of the protrusion 2e and the master cylinder 1 (for example, when the master cylinder 1 is first installed in the vehicle or when the hydraulic oil stored in the reservoir is replaced), the union 20 and the port from the reservoir are removed. A plurality of recesses 2f for introducing hydraulic oil into the pressure chamber 10 via 11 are provided alternately at equal intervals in the circumferential direction.

Next, the shape of the inner wall of the pressure chamber 10 of the housing 2 will be described with reference to FIG. On the inner wall of the pressure chamber 10, in the axial direction, a plurality of protrusions 2e having the same diameter as the outer diameter of the piston 6 and a plurality of recesses 2f formed between the adjacent protrusions 2e are formed in the circumferential direction. And the width L1 of the recess 2f is equal to the width L of the protrusion 2e.
It is larger than 2. In FIG. 2, eight protrusions 2e and eight recesses 2f are integrally formed in the housing 2. Thus, the protrusions 2e and the recesses 2f are alternately arranged at equal intervals in the circumferential direction of the pressure chamber 10 provided in the housing 2.

A protrusion 2 formed on the inner wall of the housing 2.
Since the outer diameter of the piston 6 and the inner diameter of the tip of the protrusion match when the piston 6 slides, e functions as a guide for the piston 6. On the other hand, the concave portion 2f provided between the protruding portions 2e adjacent to each other in the circumferential direction is formed by
Even when the piston 6 slides inside 0, a gap is formed in the axial direction between the recess 2f and the outer diameter of the piston 6, and the formation of the recess 2f causes the piston 6 to contact the inner diameter of the communication hole 2aa. Even when it moves to the full contact end, the flow passage between the pressure chamber 10 and the seal member 4 is ensured.

Next, the structure of the seal member 4 of the present invention will be described. In the present invention, the pressure chamber 10 and the port 11 are
The structure of the seal member 4 is characterized in that communication / blocking is performed. FIG. 3 shows the shape of the seal member alone in the first embodiment. The seal member 4 is made of an elastic member made of annular rubber or the like. This seal member 4 is shown in FIG.
As shown in FIG. 1, when assembled in the master cylinder 1, the base portion 4a extending in the radial direction and the direction in which the piston 6 slides from the inner diameter side (piston side) of the base portion 4a (the front-back direction shown in FIG. 1) ) Has an inner peripheral rib 4b and an outer peripheral rib 4c extending obliquely with a predetermined angle from the outer diameter side of the base portion 4a toward the front, and the seal member 4 has a substantially cross-section. It has a U shape. In the seal member 4 according to this embodiment, the axial width of the base portion 4a is substantially equal to the radial width of the inner diameter rib 4b and the radial width of the outer diameter rib 4c, and the rear end of the inner diameter rib 4b has the outer diameter. It has a tapered surface 4d that widens toward the side. When the piston 6 moves in the axial direction, the inner diameter rib 4b maintains a seal by the pressure contact force to the piston 6. Further, when the seal member 4 moves when the piston 6 moves, if the outer peripheral end in front of the piston 6 or the communication hole 6b formed in the piston 6 reaches the position of the inner diameter rib 4b in which the seal member 4 is arranged, Four
Since the inner diameter end at the rear of b has a tapered surface 4d that widens toward the outer diameter side, the tapered surface 4d of the seal member 4 does not exert a pressure contact force on the piston side. For this reason,
Since the tapered surface 4d can be prevented from being caught by the outer peripheral end in front of the piston 6 or the communication hole 6b, the piston 6 can slide smoothly in the axial direction, and the generation of abnormal noise due to this catching can be prevented. In this case, the width of the base portion 4a in the sliding direction of the piston 6 is as shown in FIG.
, The diameter of the communication hole 6b is substantially the same as that of the base portion 4
When the taper surface 4d is formed in the width range of a, no pressure contact force is generated at that portion, and the remaining inner diameter ribs 4b have substantially the same thickness, so that the pressure contact force on the piston side is reduced. The inner peripheral surface of the inner peripheral rib 4b can be made more uniform than in the conventional case.

As shown in FIG. 4, the seal member 4 having such a structure closes the small diameter through hole 6b by the seal member 4 as the piston 6 moves, thereby blocking the communication between the pressure chamber 10 and the port 11. To do. In this state, the fluid pressure P1 acting on the inner peripheral rib 4b of the seal member 4 and the fluid pressure P2 acting on the inner peripheral rib 4b of the seal member 4 from the communication hole 6b are equal to each other (the fluid pressures P1 and P2 are equal to each other). The same as the pressure of 10), and only the pressure contact force of the outer peripheral rib 4c in the assembled state of the seal member 4 in the housing acts on the communication hole 6b having a small diameter. As a result, a pressure contact force acts on the sliding surface between the seal member 4 and the piston 6, but by forming the tapered surface 4d at the rear end of the inner peripheral rib 4b, the inner peripheral rib due to the movement of the piston 6 is formed. 4b can be prevented from being caught.

Next, the operation of the master cylinder 1 will be described. FIG. 1 shows a non-operation state in which the clutch pedal is not depressed (that is, a state where the clutch is completely engaged).
At the position of the piston 6 in this state, the communication hole 6b
The axial position of the taper surface 4d of the seal member 4
It is located rearward of the portion in which is formed, and in this state, the communication hole 2ba and the small diameter hole 6b communicate with each other. Then, the pressure chamber 10 communicates with the port 11, and the pressure chamber 10 is in a pressureless state in which no internal pressure acts.

When a clutch pedal (not shown) is depressed from this state, the piston 6 is pushed by the rod 7 due to the axial movement of the rod 7 connected to the clutch pedal, and the piston 6 moves forward in the axial direction. . Then, the communication hole 6 b of the piston is not connected to the tapered surface 4 of the seal member 4.
When a pressure contact force is generated by the inner peripheral rib 4b after passing through d, the outer peripheral surface of the piston 6 and the inner diameter of the inner peripheral rib 4b come into close contact with each other, and communication between the communication hole 6b communicating with the pressure chamber 10 and the port 11 is blocked. . As a result, with the forward movement of the piston 6, the volume of the pressure chamber 10 is reduced, and pressurization is started. The hydraulic oil existing in the pressure chamber 10 in the unpressurized state is discharged from the port 8 through the communication hole 2aa as the piston 6 moves forward. Depending on the discharged pressure,
The hydraulic oil is introduced into the clutch operating cylinder connected to the port 8 to disengage the clutch.

In this case, when the piston 6 moves in the axial direction, an internal pressure corresponding to the clutch reaction force is generated in the pressure chamber 10, and the load corresponding to the pressure receiving area of the seal member 4 causes the support ring 12 to drop from the housing 1. However, in the present embodiment, the support ring 12 is fixed integrally with the housing 2 by the fixing pin 13, so that the support ring 12 is fixed to the seal member 5 and the guide sleeve 3.
This load has no effect.

Next, a second embodiment will be described. The shape of the seal member 4 in the second embodiment is basically the same as that of the first embodiment shown in FIG. 3, but as shown in FIG. 5, the inner peripheral surface of the inner diameter rib 4b is in contact with the piston 6 and is uneven. The difference is that it has a portion 4e. In this way, by forming the uneven portion 4e on the inner diameter of the inner diameter rib 4b that is in close contact with the piston 6, when the piston 6 moves in the axial direction, or when the contact area with the outer peripheral surface of the piston 6 does not have the uneven portion 4e. (See the state of FIG. 6), the sliding resistance at the time of piston movement is reduced, and the piston 6 can slide smoothly on the uneven portion 4e. Even in this case, since the tapered surface 4d is formed at the rear end of the seal member 4, it is possible to prevent the seal member 4 from being caught in the piston 6, and to prevent abnormal noise from occurring when the piston 1 slides. .

Further, in this structure, by forming the oil film layer on the uneven portion 4e, the sliding resistance in the movement of the piston 6 is reduced, and the piston 6 can be moved more smoothly.

FIG. 7 shows a third embodiment. This configuration
Instead of the radial communication hole 6b shown in FIG. 1, a plurality of axial groove portions 6f are formed in the piston 6, and the other configurations are the same as those in the first embodiment, and therefore description thereof is omitted. . Here, the inner peripheral surface of the seal member 4 of the third embodiment, which is in close contact with the piston 6 of the inner diameter rib 4b, may have the uneven portion 4e similar to that of the embodiment of FIG.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-mentioned embodiments and may be applied to a brake master cylinder other than the clutch master cylinder, for example.

[0035]

According to the present invention, the seal member is within the range of the width of the base portion in the sliding direction in which the sliding member slides.
Since the inner peripheral rib has a tapered surface, when the sliding member slides, the pressure contact force against the sliding member does not act on the inner diameter side when the sliding member slides, and the seal due to the movement of the sliding member Occurrence of biting of the member can be suppressed. As a result, it is possible to reduce damage caused by the sliding member being caught in the seal member.

In this case, when the uneven portion is formed on the sliding contact surface of the inner peripheral rib with the sliding member, the sliding contact surface with the sliding member is contacted by the uneven portion with the inner diameter of the inner peripheral rib and the sliding member. The area is reduced, and the sliding resistance is reduced and the movement of the sliding member can be made smoother than in the case where the entire inner circumferential surface of the inner circumferential rib is in sliding contact with the sliding member.

Further, when the oil film layer is formed on the uneven portion, the oil film layer on the uneven portion reduces the sliding resistance when the sliding member moves, so that the sliding member can move more smoothly.

[Brief description of drawings]

FIG. 1 is a sectional view showing a configuration of a pressure generator according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along the line AA shown in FIG.

FIG. 3 is a cross-sectional view showing the shape of the seal member shown in FIG.

FIG. 4 is a partial enlarged view of essential parts showing a pressure state acting on the seal member shown in FIG. 1.

FIG. 5 is a cross-sectional view showing the shape of a seal member according to the second embodiment.

FIG. 6 is a partial enlarged view of essential parts showing a sealing state in a communication hole communicating with a pressure chamber by a seal member in the second embodiment.

FIG. 7 is a partial enlarged view showing a relationship between a seal member and a piston according to a third embodiment.

FIG. 8 is a conventional example, (a) is a cross-sectional view of a seal member,
(B) is a partial enlarged view showing a state of the seal member and the communication hole due to movement of the piston, and (c) is an explanatory view showing a pressure contact force of the seal member with respect to the piston.

[Explanation of symbols]

1 Master cylinder (pressure generator) 2 housing 4 Seal member 4a base part 4b Inner circumference rib 4c Outer rib 4d taper surface 4e Concavo-convex part 4f oil film layer 6 Piston (sliding member) 10 Pressure chamber 11 ports

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Claims (3)

[Claims] 1. A pressure chamber formed in a housing, a port communicating with the pressure chamber, a base portion, an outer peripheral rib extending from the base portion, and a sliding member extending from the base portion. A seal member that has an inner peripheral rib that is in sliding contact with the pressure chamber and that is interposed between the pressure chamber and the port; and a sliding member that slides in the pressure chamber to change the volume of the pressure chamber. In the pressure generating device which makes the pressure chamber a high pressure by blocking the pressure chamber and the port by the movement of the sliding member, the sealing member slides on the sliding member. The pressure generating device is characterized in that the inner peripheral rib has a tapered surface that widens toward the outer diameter side within the width range of the base portion in the sliding direction. 2. The pressure generator according to claim 1, wherein an uneven portion is formed on a sliding contact surface of the inner peripheral rib with the sliding member. 3. The pressure generator according to claim 2, wherein the uneven portion is coated with an oil film layer.