JP2014100947A - Cylinder device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a seal function between a cylinder portion and a piston by a seal member using a cup seal.SOLUTION: At a position corresponding to a seal member 13 of an outer peripheral wall of a piston 5, a groove portion 5b including a guide face 5c formed to be an inclined face by gradually reducing an outer diameter of the piston toward a compression movement direction is formed. An inner peripheral face of an inner lip 13b of the seal member 13 is formed to be an inclined face having an inner diameter reduced from a side of a cup bottom face 13a toward a lip tip, and an inner diameter of the tip of the inner lip 13b is made smaller than an inner diameter of a cylinder portion 2, so that the tip enters into the groove portion 5b. An inner diameter of the cup bottom face 13a is made larger than an outer diameter of a sliding face of the piston 5 that is slid within the cylinder portion 2. When the piston 5 is moved in the compression movement direction according to operating force, the tip of the inner lip 13b is brought into contact with the outer peripheral face of the piston on the guide face 5c, so as to seal a space between the inner peripheral face of the cylinder portion 2 and the outer peripheral face of the piston 5.

Description

  The present invention relates to a cylinder device that generates a pressure in a fluid in a cylinder as a piston disposed in the cylinder moves. For example, it is suitable for use in a cylinder device applied to a brake system, such as a master cylinder, a hydro booster or a vacuum booster.

  Conventionally, Patent Document 1 proposes a master cylinder provided with a seal member made of a cup seal (sealing cup) for achieving liquid tightness between an inner wall surface of a cylinder portion and a piston. In this master cylinder, a groove having a reduced outer diameter is formed on the outer peripheral wall of the piston, an inclined wall is provided in the groove, and a cup seal is disposed at a position where the inclined wall is formed. The inclined wall is located outside the outer peripheral wall of the piston in the direction of movement of the piston as the brake pedal is depressed, that is, in the direction of movement when pressurizing the brake fluid pressure in the master cylinder (hereinafter referred to as the pressure movement direction). It is a tapered wall with a reduced diameter. The cup seal is arranged so that the brake pedal side is the cup bottom (base) and the opposite side is the lip (opening), and the inner lip is reduced radially inward from the cup bottom toward the lip tip. The lip has a shape expanded radially outward. The cup seal is configured such that the inner diameter of the cup bottom is smaller than the outer diameter of the portion of the piston that is not a groove, and the cup seal is fitted into the groove.

  In the master cylinder having such a configuration, when the piston is moved as the brake pedal is depressed, the cup seal is crushed by the inclined surface. When the piston is further moved, the groove moves to disengage the cup seal from the groove, and the cup seal is placed in the portion of the piston where the outer diameter is not the largest. . Thereby, the liquid tightness between the inner wall surface of the cylinder part and the piston is achieved.

JP 2009-280200 A

  However, in the seal structure described in Patent Document 1, the cup seal is crushed by pressing the cup bottom surface of the cup seal against the inclined surface of the groove of the piston. For this reason, the tip of the inner lip is separated from the inner wall surface of the piston, and the tip of the lip is not sufficiently pressed against the inner wall surface of the piston, which may result in insufficient sealing.

  An object of this invention is to provide the cylinder apparatus which can aim at the improvement of the sealing function between the cylinder part and piston by the sealing member using a cup seal in view of the said point.

  In order to achieve the above object, according to the first aspect of the present invention, the piston of the piston (5, 6) is positioned at a position corresponding to the seal member (13, 15) on the outer peripheral wall of the piston toward the pressurizing movement direction. Second grooves (5b, 6b) including guide surfaces (5c, 6c) that are inclined surfaces are formed by gradually reducing the outer diameter. The sealing member is inclined by reducing the inner diameter of the inner lip (13b, 15b) from the cup bottom (13a, 15a) side toward the lip tip, and the tip of the inner lip. The inner diameter of the cup is reduced more than the inner diameter of the cylinder part (2), and the tip is inserted into the second groove part. When the piston is moved in the direction of pressurization and movement based on the operating force, the inner lip tip comes into contact with the outer peripheral surface of the piston at the guide surface. A seal between the peripheral surface and the outer peripheral surface of the piston is performed.

  In this way, only the tip of the inner lip is disposed in the second groove portion, and the inner diameter of the cup bottom surface is made larger than the outer diameter of the sliding surface of the piston that can be slid within the cylinder portion. For this reason, the outer peripheral surface of the piston comes into contact with the tip of the inner lip, and the bottom surface of the cup can be prevented from being crushed. Therefore, the tip of the inner lip can be reliably brought into contact with the outer peripheral surface of the piston, and the range of the contact portion can be widened, so that the sealing can be performed more reliably. Thereby, it becomes possible to improve the sealing function between the cylinder portion and the piston by the sealing member constituted by the cup seal.

  In addition, the code | symbol in the bracket | parenthesis of each said means shows an example of a corresponding relationship with the specific means as described in embodiment mentioned later.

It is a figure showing the section composition of master cylinder 1 concerning a 1st embodiment of the present invention. It is a partial expanded sectional view of the vicinity of the seal part 13 (15). It is the elements on larger scale which showed the mode of the vicinity of seal part 13 (15) when pistons 5 and 6 are moved in the pressurization movement direction. It is sectional drawing which showed the mode of the seal | sticker part 13 (15) when a seal | sticker was made when it was made to contact the outer peripheral surface of piston 5,6 previously. It is sectional drawing which showed the mode of the seal part 13 (15) when a seal | sticker was made when it was set as the structure shown in FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, parts that are the same or equivalent to each other will be described with the same reference numerals.

(First embodiment)
A first embodiment of the present invention will be described. A case where one embodiment of the present invention is applied to a master cylinder provided in a vehicle brake device will be described.

  A master cylinder 1 shown in FIG. 1 is connected to a push rod of a booster (not shown) that is operated based on depression of a brake pedal (not shown). The master cylinder 1 is provided with a cylindrical cylinder portion 2 having a hollow portion, and a brake pipe (not shown) is connected to a primary chamber 3 and a secondary chamber 4 configured in the cylinder portion 2, and the brake pipe The brake fluid pressure is transmitted to the wheel cylinder through.

  Specifically, the master cylinder 1 generates brake fluid pressure (hereinafter referred to as master cylinder pressure) in the primary chamber 3 and the secondary chamber 4 when the brake pedal is depressed. Then, the master cylinder pressure is transmitted to each wheel cylinder (not shown) through the brake pipes of the first and second pipe systems connected to the master cylinder 1 to generate a braking force.

  The master cylinder 1 is provided with a primary piston 5 and a secondary piston 6, and a primary chamber 3 and a secondary chamber 4 are constituted by the chambers defined by the pistons 5 and 6 and the inner wall surface of the cylinder part 2. Each piston 5, 6 has a bottomed cylindrical shape, and the outer peripheral wall is arranged along the inner peripheral surface of the cylinder part 2, so that the piston 5, 6 can slide inside the cylinder part 2. It is said that. And the primary chamber 3 is comprised by the inner wall face of the primary piston 5, the bottom face of the secondary piston 6, and the inner wall face of the cylinder part 2, and the secondary chamber 4 is comprised by the inner wall face of the secondary piston 6 and the inner wall face of the cylinder part 2. Yes.

  In addition, the master cylinder 1 is provided with a master reservoir 7, and the primary chamber 3 and the secondary chamber 4 and the master reservoir 7 are communicated with each other through ports 8 and 9 formed in the cylinder portion 2. ing. The ports 8 and 9 are not blocked by the pistons 5 and 6 when the brake pedal is not depressed and the pistons 5 and 6 are positioned at the initial position, and the primary reservoir 7 3 and the flow of the brake fluid to the secondary chamber 4 are permitted. Specifically, ports 5a and 6a connected to the ports 8 and 9 at the initial position are formed on the outer peripheral walls of the pistons 5 and 6, and the chambers 4 and 5 are connected from the master reservoir 7 through the ports 5a and 6a. Allow the brake fluid to flow.

  When the brake pedal is depressed and the pistons 5 and 6 are moved, the positions of the ports 5a and 6a of the pistons 5 and 6 and the ports 8 and 9 of the master reservoir 7 are shifted. Therefore, the ports 8 and 9 are closed by the pistons 5 and 6, and the master reservoir 7 is blocked from the primary chamber 3 and the secondary chamber 4 to inhibit the flow of brake fluid. Thereby, a master cylinder pressure is generated in the primary chamber 3 and the secondary chamber 4, and this is transmitted to each wheel cylinder through the brake piping of the first and second piping systems so as to generate a braking force on each wheel. It has become.

  Springs 10 and 11 are provided between the pistons 5 and 6 and between the wall surface of the cylinder portion 2 opposite to the brake pedal and the secondary piston 6, and the pistons 5 and 6 are arranged in the initial position direction. It is energized. For this reason, when the brake pedal is depressed, the pistons 5 and 6 are moved to the opposite side of the brake pedal against the elastic force of the springs 10 and 11. When the depression of the brake pedal is stopped, the pistons 5 and 6 are returned to their initial positions by the elastic force of the springs 10 and 11.

  A retainer 20, a stopper 21 and a rod 22 are disposed between the pistons 5 and 6. The retainer 20 is assembled to the primary piston 5, and the stopper 21 is fixed to the secondary piston 6. The rod 22 is fixed to the retainer 20 and is assembled with respect to the stopper 21 so as to be able to move a predetermined amount in the same direction as the pressurizing movement direction of the pistons 5 and 6.

  The primary chamber 3 and the secondary chamber 4 are connected to the brake pipes of the first and second piping systems through outlet ports 23 and 24 connected to the primary chamber 3 and the secondary chamber 4 provided in the cylinder portion 2. It has been broken.

  In such a configuration, grooves 2 a and 2 b are formed at locations corresponding to the outer peripheral wall of the primary piston 5 on the inner peripheral surface of the cylinder portion 2. Each groove part 2a, 2b is formed so that the outer periphery of the primary piston 5 may surround 1 circumference. When the primary piston 5 is located at the initial position, each groove 2a, 2b is located closer to the brake pedal than the ports 5a, 8 and the groove 2b is opposite to the brake pedal from the port 8. It is formed to be located on the side. Groove portions 2c and 2d are also formed in the cylinder portion 2 at locations corresponding to the outer peripheral wall of the secondary piston 6. Each groove part 2c, 2d is formed so that the outer periphery of the secondary piston 6 may surround 1 circumference. When the secondary piston 6 is positioned at the initial position, each groove 2c, 2d is positioned closer to the brake pedal than the ports 6a, 9, and the groove 2d is opposite to the brake pedal from the port 9. It is formed to be located on the side.

  Seal members 12 to 15 made of an elastic body such as rubber are disposed in the groove portions 2a to 2d.

  The seal members 12 and 14 have the same configuration and are configured by cup seals. The seal member 12 is disposed closer to the brake pedal than the port 8, and the lip portion is directed to the port 8 side. From the port 8 side between the cylinder portion 2 and the primary piston 5 to the outside of the master cylinder 1. Prevents brake fluid leakage. The seal member 14 is disposed on the brake pedal side with respect to the port 9, the cup bottom surface is directed to the port 9 side, and between the cylinder portion 2 and the primary piston 5, between the port 9 and the outlet port 23. It is sealed.

  The seal members 13 and 15 have the same configuration. The seal member 13 is disposed on the opposite side of the brake pedal from the port 8, and the seal member 15 is disposed on the opposite side of the brake pedal from the port 9. Yes. The seal members 13 and 15 are also constituted by cup seals, and as shown in FIG. 2, the brake pedal side is cup bottom surfaces 13a and 15a, and the opposite side is lips (openings) 13b, 13c, 15b and 15c. Has been placed. The seal members 13 and 15 have inner diameters of the inner lips 13b and 15b that are reduced from the cup bottom surfaces 13a and 15a toward the tip of the lip, and the outer lips 13c and 15c are in the direction of pressure movement of the pistons 5 and 6, respectively. And parallel. For this reason, the inner lip 13b, 15b reduced in diameter radially inward is in a state in which the inner peripheral surface is inclined at a predetermined angle with respect to the pressurizing movement direction.

  More specifically, as shown in FIG. 2, the inner peripheral surfaces of the inner lips 13b and 15b are uneven surfaces formed with a plurality of concave portions 13d and 15d and a plurality of convex portions 13e and 15e. Among these, the tip of each convex portion 13e, 15e is a portion that is brought into contact with each piston 5, 6 when the brake pedal is depressed, and the inner lip 13b, 15b is not in contact with each piston 5, 6; A straight line connecting the tips of the convex portions 13e and 15e (in the cross-section (paper surface) direction in FIG. 2) is inclined at a predetermined angle with respect to the pressurizing movement direction.

  Further, the seal members 13 and 15 have the cup bottoms 13a and 15a and the outer lips 13c and 15c whose outer diameters are substantially matched with the diameters of the bottoms of the grooves 2b and 2d, and are accommodated in the grooves 2b and 2d. The outer peripheral surfaces of the outer lips 13c and 15c and the cup bottom surfaces 13a and 15a are brought into contact with the bottom surfaces of the groove portions 2b and 2d. The inner diameters of the cup bottom surfaces 13a and 15a are made larger than the outer diameters of the sliding surfaces of the pistons 5 and 6 that are slidable in the cylinder portion 2, and the pistons 5 and 6 are moved under pressure by depressing the brake pedal. The cup bottom surface 13a is not crushed by the pistons 5 and 6 when moved in the direction. Further, the inner lips 13b, 15b have a smaller inner diameter than the inner diameter of the cylinder portion 2 at the tip, and protrude from the grooves 2b, 2d at the tip.

  In addition, as shown in FIG. 2, grooves 5 b and 6 b with reduced outer diameters are formed on the outer peripheral walls of the pistons 5 and 6 at positions corresponding to the seal members 13 and 15. As described above, the ends of the inner lips 13b and 15b protruding from the groove portions 2b and 2d are in a state of entering the groove portions 5b and 6b when the pistons 5 and 6 are located at the initial positions. .

  The groove portions 5b and 6b have guide surfaces 5c and 6c constituted by inclined surfaces that are gradually reduced in diameter in the pressurizing movement direction. The inclination angles of the guide surfaces 5c, 6c are the inclination angles on the inner peripheral surface side of the inner lips 13b, 15b (the tips of the convex portions 13e, 15e The inclination angle of the connecting straight line), and these inclinations are parallel. When the brake pedal is not depressed, that is, when the pistons 5 and 6 are in the initial position, the guide surfaces 5c and 6c are separated from the convex portions 13e and 15e or they are in contact with each other with almost no load. It becomes a state.

  The master cylinder 1 concerning this embodiment is comprised by the above structures. When the brake pedal is depressed, the master cylinder 1 configured in this manner generates master cylinder pressure by sliding the pistons 5 and 6 in the cylinder portion 2 in the pressurizing movement direction based on the depression force. Let

  At this time, as shown in FIG. 3, the pistons 5 and 6 are moved, so that the grooves 5 b and 6 b are also moved to the inner side of the cylinder 2 (opposite to the brake pedal). For this reason, the tips of the inner lips 13b and 15b protruding into the grooves 5b and 6b come into contact with the guide surfaces 5c and 6c and are pushed outward in the radial direction. However, only the tips of the inner lips 13b and 15b are disposed in the grooves 5b and 6b, and the inner diameters of the cup bottom surfaces 13a and 15a are the outer diameters of the sliding surfaces of the pistons 5 and 6 that can be slid in the cylinder part 2. Has been bigger than. For this reason, the outer peripheral surfaces of the pistons 5 and 6 come into contact with the tips of the inner lips 13b and 15b, and the cup bottom surfaces 13a and 15a are not crushed.

  Therefore, the tips of the inner lips 13b and 15b can be surely brought into contact with the outer peripheral surfaces of the pistons 5 and 6, and the range of the contact portions can be widened, so that the sealing can be performed more reliably. Thereby, it becomes possible to improve the sealing function between the cylinder portion 2 and the pistons 5 and 6 by the sealing members 13 and 15 configured by cup seals. And since it becomes a structure which can seal reliably at the time of the action | operation of the master cylinder 1 accompanying a brake pedal operation, it can become difficult to produce the difference in the sealing performance by the slow speed of an operating speed.

  As shown in FIG. 3, when the pistons 5 and 6 are in the initial positions, the convex portions 13e and 15e on the outer peripheral surface of the inner lips 13b and 15b are separated from the guide surfaces 5c and 6c, or these are It is in a state of contact without applying a load. Therefore, in a state before the brake pedal is depressed, the recesses 13d and 15d are sufficiently filled with the brake fluid, and the surfaces of the projections 13e and 15e are also in contact with the brake fluid. It has become. In particular, when the convex portions 13e and 15e are separated from the guide surfaces 5c and 6c when the pistons 5 and 6 are in the initial position, the entire surface of the convex portions 13e and 15e is in contact with the brake fluid. Can be.

  Therefore, as shown in FIG. 4A, when the outer peripheral surfaces of the pistons 5 and 6 are contacted in advance, the tips of the convex portions 13e and 15e are crushed, but in FIG. As shown, in the configuration of the present embodiment, the amount of crushing of the tips of the convex portions 13e and 15e can be reduced. That is, in the example of FIG. 4A, the seal portions at the tips of the convex portions 13 e and 15 e are in line contact with the outer peripheral surfaces of the pistons 5 and 6 in the cross section shown in the drawing. However, in the present embodiment, these are point contacts in the cross section shown in FIG. 4B. Thereby, the sliding resistance of the pistons 5 and 6 can be reduced.

  In particular, since the straight line connecting the tips of the protrusions 13e and 15e and the guide surfaces 5c and 6c are parallel, each of the protrusions 13e and 15e contacts the guide surfaces 5c and 6c evenly, and some of the protrusions 13e and 15e can also be prevented from being crushed excessively, and the above effect can be obtained more. Thereby, the sliding resistance of the seal portion is further reduced, and the pressure in the primary chamber 3 and the secondary chamber 4 can be efficiently generated with respect to the input from the brake pedal. That is, the pressure in the primary chamber 3 and the secondary chamber 4 can be brought close to the ideal pressure.

  Further, when the pistons 5 and 6 are further stepped on from the state of FIG. 3 and the inner lips 13b and 15b are pushed to reach the state of FIG. 4B, the brake fluid in the lip correspondingly flows into the chambers 3 and 3, respectively. 4 will be supplied. Therefore, the amount of oil supplied to the wheel cylinder can be increased, and the braking effect can be accelerated.

(Other embodiments)
In the above embodiment, as an example of a cylinder device having a piston that is moved in the pressurizing direction when an operating force is applied in the cylinder portion, a master in which the pistons 5 and 6 are moved by using the depression force of the brake pedal as the operating force. The cylinder 1 has been described as an example. However, as long as the cylinder device includes a piston in the cylinder portion and seals between the outer peripheral surface of the piston and the inner peripheral surface of the cylinder portion with a seal member, other devices such as a clutch master cylinder, a hydro booster, and a vacuum booster It can also be applied.

  In addition, this invention is not limited to above-described embodiment, In the range described in the claim, it can change suitably. For example, with respect to the shape of the sealing members 13 and 15 configured by cup seals, the inner lips 13b and 15b are inserted into the grooves 5b and 6b, while the cup bottom surfaces 13a and 15a have inner diameters outside the pistons 5 and 6. Other shapes may be used as long as they are larger than the diameter.

  Further, from the viewpoint of improving the durability of the inner lips 13b and 15b, both end portions in the pressure movement direction of the grooves 5b and 6b, at least the end portion on the side opposite to the pressure movement direction, are rounded. desirable.

  DESCRIPTION OF SYMBOLS 1 ... Master cylinder, 2 ... Cylinder part, 2b, 2d ... Groove part (1st groove part), 3 ... Primary chamber, 4 ... Secondary chamber, 5 ... Primary piston, 6 ... Secondary piston, 5a, 6a ... Port, 5b, 6b ... groove (second groove), 5c, 6c ... guide surface, 7 ... master reservoir, 10 ... spring, 12-14 ... seal member, 13a, 15a ... cup bottom, 13b, 15b ... inner lip, 13c, 15c ... outside Lip, 13d, 15d ... concave, 13e, 15e ... convex

Claims (4)

A cylinder part (2) having a hollow part in which a fluid is accommodated and having a first groove part (2b, 2d) formed around the inner periphery on the inner peripheral surface;
A seal member (13, 15) configured by a cup seal disposed in the first groove and having a cup bottom surface (13a, 15a) and an inner lip (13b, 15b);
A piston (5) that is slidably disposed in the hollow portion with the inner peripheral surface of the cylinder portion as a sliding surface and is moved in a pressurizing movement direction that pressurizes the fluid in the cylinder portion when an operating force is applied. 6)
Positions corresponding to the seal member in the outer peripheral wall of the piston include guide surfaces (5c, 6c) that are inclined surfaces by gradually reducing the outer diameter of the piston toward the pressurizing movement direction. The second groove (5b, 6b) is formed,
The seal member has an inner circumferential surface of the inner lip that is inclined by reducing the inner diameter from the cup bottom surface toward the lip tip, and the inner lip of the inner lip has an inner diameter smaller than the inner diameter of the cylinder portion. Is reduced, and the tip is inserted into the second groove, and the inner diameter of the cup bottom surface is larger than the outer diameter of the sliding surface of the piston that is slidable in the cylinder portion. When the piston is moved in the pressurizing movement direction based on the operating force, the tip of the inner lip comes into contact with the outer peripheral surface of the piston at the guide surface. A cylinder device characterized in that a seal is provided between a surface and an outer peripheral surface of the piston.   The inner peripheral surface of the inner lip is an uneven surface in which a plurality of concave portions (13d, 15d) and a plurality of convex portions (13e, 15e) are formed, and the piston is pressurized by the operating force. When moved in the movement direction, the tips of the plurality of convex portions are brought into contact with the guide surface, and the straight line connecting the tips of the plurality of convex portions in a state where the inner lip is not in contact with the piston. The cylinder device according to claim 1, wherein is parallel to the guide surface.   The seal member includes an outer lip (13c, 15c), the outer lip is provided in parallel with the pressure movement direction, and the outer peripheral surface of the outer lip and the cup bottom surface is on the bottom surface of the first groove portion. The cylinder device according to claim 1, wherein the cylinder device is contacted.   The inner lip is separated from the guide surface when the piston is in an initial position before the piston is moved in the pressurizing movement direction based on the operation force. 4. The cylinder device according to any one of 3.

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