JP5206988B2 - Cylinder device - Google Patents

Description

  The present invention relates to a cylinder device such as a hydraulic shock absorber.

  For example, in a cylindrical hydraulic shock absorber attached to an automobile, the opening end of the cylinder is prevented from coming off by caulking a seal case and an oil seal.

JP 2004-251413 A

  In a hydraulic buffer having a high pressure in the gas chamber, a large force is applied to the caulking portion via the seal case and the oil seal, so that further improvement in pressure resistance is desired.

  An object of this invention is to provide the cylinder apparatus which improved the pressure | voltage resistance of the opening end of an outer cylinder.

In order to solve the above-described problems, a cylinder device according to the present invention includes an outer cylinder in which hydraulic fluid is sealed and at least one end opened, a piston inserted into the outer cylinder, and a piston connected to the piston. A piston rod projecting to the outside of the cylinder, an annular seal case provided at one end in the outer cylinder, an outer peripheral seal that seals between the outer cylinder and the seal case, and an inner periphery of the seal case An annular rod seal that slides with the piston rod, and an annular oil seal that slides with the piston rod provided at one end of the seal case,
The seal case is provided with an outer circumferential groove, and is fixed to the outer cylinder by a first caulking portion that caulks the outer cylinder from the outside into the outer circumferential groove, and the oil seal is a first caulking the outer cylinder from the outside. It is fixed to the outer cylinder by two caulking parts ,
The outer peripheral seal is disposed on both axial sides with respect to the first caulking portion.

  According to the cylinder device according to the present invention, the pressure resistance of the open end of the outer cylinder can be increased.

It is a longitudinal cross-sectional view which expands and shows the seal | sticker of the piston rod which is the principal part of the cylinder apparatus which concerns on 1st Embodiment of this invention. It is a longitudinal cross-sectional view which expands and shows the seal | sticker of the piston rod which is the principal part of the cylinder apparatus which concerns on 2nd Embodiment of this invention. It is a longitudinal cross-sectional view of the cylinder apparatus shown in FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
With reference to FIG.1 and FIG.3, the cylinder apparatus 1 which concerns on 1st Embodiment of this invention is demonstrated. The cylinder device 1 according to the present embodiment is mounted on each of the front and rear and left and right wheel suspension devices of an automobile, and these are connected to each other via an external hydraulic circuit by a pipe line, and their operations are interlocked. This is to control the vibration and posture of the vehicle body by controlling the flow of hydraulic fluid between the cylinder devices caused by the posture change of the vehicle body by an accumulator and a damping valve of an external hydraulic circuit.

  As shown in FIGS. 1 and 3, the cylinder device 1 has a double cylinder structure in which a cylindrical outer cylinder 3 is provided on the outer periphery of a cylinder 2 and an annular passage 4 is formed therebetween. . A piston 5 is slidably inserted into the cylinder 2. The piston 5 partitions the inside of the cylinder 2 into two chambers, a cylinder chamber 2A and a cylinder chamber 2B. One end of a piston rod 6 is connected to the piston 5 by a nut 7, and the other end of the piston rod 6 slides on a rod guide 8 and an oil seal 9 attached to the lower ends of the cylinder 2 and the outer cylinder 3. It is inserted in a liquid-tight manner and protrudes to the outside. The cylinder chamber 2 </ b> A and the annular passage 4 are communicated with each other by a notch 12 provided in the rod guide 8.

  A damping valve 13 is attached to the upper end portion of the cylinder 2, and the damping valve 13 is fixed by a passage member 14 welded to the upper end portion of the outer cylinder 3. A connection port 15 is passed through the passage member 14 along the axial direction, the cylinder chamber 2B is communicated with the connection port 15 via the damping valve 13, and the upper end portion of the annular passage 4 is connected by the damping valve 13 and the passage member 14. It is closed. The damping valve 13 has a check valve that allows the flow of hydraulic fluid from the connection port 15 side to the cylinder chamber 2B side, and a damping force by controlling the flow of hydraulic fluid from the cylinder chamber 2B side to the connection port 15 side. A damping mechanism including an orifice to be generated and a disk valve is provided.

  An opening 16 is provided in an intermediate portion of the side wall of the outer cylinder 3, and a damping force generation mechanism 17 is connected to the opening 16. The damping force generation mechanism 17 includes a cylindrical valve case 18 whose one end is reduced in diameter, a damping valve 19 accommodated in the valve case 18, and a nut 20 at an opening end portion on the large diameter side of the valve case 18. And an attached connecting member 21.

  An annular joint 23 projects around the opening 22 on one end side of the valve case 18 whose diameter has been reduced. The valve case 18 is joined to the outer cylinder 3 by bringing the joint 23 into contact with the outer peripheral surface around the opening 16 of the outer cylinder 3 and welding the joint 23 to the side wall of the outer cylinder 3.

  The connection member 21 is provided with a connection port 24 communicating with the inside of the valve case 18. The damping valve 19 has a check valve 25 that allows only the flow of hydraulic fluid from the connection port 24 side to the opening 22 side, and controls and attenuates the flow of hydraulic fluid from the opening 22 side to the connection port 24 side. A disk valve 26 having an orifice 26A for generating a force is provided.

Next, the structure of the seal portion S of the piston rod 9, which is the main part of the present embodiment, will be described mainly with reference to FIG.
As shown in FIG. 1, an annular rod guide 8 through which the piston rod 6 penetrates, a seal case 27, an oil seal 9, a dust seal 28, and a retainer 29 are inserted and fixed to the lower end portion of the outer cylinder 3 in this order. ing.

  One end of the rod guide 8 is fitted into the end of the cylinder 2, and a flange 8 </ b> A formed on the outer periphery of the intermediate portion is in contact with the end of the cylinder 2 and is positioned in the axial direction. The portion is fitted in the recess 30 formed in the seal case 27. A notch 12 that connects the cylinder chamber 2A and the annular passage 4 is provided at one end of the rod guide 8 and a part of the flange portion 8A. In the rod guide 8, a cylindrical low friction member 31 is press-fitted into an inner peripheral portion, and the piston rod 6 is slidably guided through the low friction member 31. The low friction member 31 is made of metal, and the surface thereof is coated with fluororesin or the like so that the rod guide 6 is not damaged when the rod guide 6 comes into sliding contact.

Seal case 27, the recess 30 the rod guide 8 is fitted is formed at one end, to the bottom of the recess 30, the small diameter of the seal recess 32 is formed than the concave portion 30. A seal groove is formed by the end portion of the rod guide 8 fitted into the recess 30 by press fitting and the seal recess 32, and the seal groove is composed of a rod seal 33 and an O-ring for sealing between the piston rod 6 and the seal groove. A backup ring 34 is attached. At the other end of the seal case 27, a recess 36 for accommodating the seal lip 35 of the oil seal 9 is formed. The rod seal 33 is a self-lubricating resin material, and is always in sliding contact with the piston rod 6 with an urgent force.

  The seal case 27 is formed with an outer peripheral groove 37 at an outer peripheral intermediate portion that fits into the outer cylinder 3, and the first caulking portion 38 that caulks the outer cylinder 3 from the outer side in the radial direction toward the outer peripheral groove 37. It is fixed to the tube 3. A seal groove 39 is formed on one end side of the outer periphery of the seal case 27 (inner side in the axial direction of the outer periphery groove 37), and an O-ring 40, which is an outer periphery seal, is provided in the seal groove 39. It is sealed between. A tapered seal surface 40 </ b> A is formed on the outer peripheral edge portion on the other end side of the seal case 27. Note that the seal case 27 and the rod guide 8 may be integrated.

  In the oil seal 9, a seal lip 35, which is a lip-shaped seal member, is fixed inside the inner peripheral portion of the disc-shaped reinforcing plate 41, and the inner peripheral portion of the seal lip 35 is in sliding contact with the piston rod 6. A tension spring 42 is attached to the outer periphery of the seal lip 35. A seal member 43 as an outer peripheral seal is fixed to one end side of the outer peripheral portion of the reinforcing plate 41, and the seal member 43 is pressed against the seal surface 40 </ b> A of the seal case 27 by the reinforcing plate 41, The space between the tube 3 is sealed. The seal lip 35 and the seal member 43 are continuous on the end surface of the reinforcing plate 41 and seal the contact portion between the reinforcing plate 41 and the seal case 27.

  In the dust seal 28, a dust lip 45, which is a lip-shaped seal member, is fixed to the outside of the inner peripheral portion of the disc-shaped reinforcing plate 44, and the inner peripheral portion of the dust lip 45 is in sliding contact with the piston rod 6. A tension spring 46 is attached to the outer periphery of the dust lip 45. The oil seal 9 and the dust seal 28 may be integrated by using the reinforcing plates 41 and 44 in common.

  The retainer 29 has a groove 47 formed in the outer peripheral portion that fits into the outer cylinder 3, and is fixed to the outer cylinder 3 by a second caulking portion 48 that caulks the outer cylinder 3 from the radially outer side into the outer peripheral groove 47. Has been. The retainer 29 presses the reinforcing plates 41 and 44 of the oil seal 9 and the dust seal 28 against the seal case 27 side to fix them. In addition, by making the 1st crimping part 38 and the 2nd crimping part 48 into the same shape, the same crimping tool can be used for these. Moreover, you may make it provide the 1st crimping part 38 and the 2nd crimping part 48 partially, for example in four places instead of a perimeter. At this time, if the first caulking portion 38 and the second caulking portion are arranged so as to be shifted in the radial direction, it is possible to reduce the number of caulking points without reducing the unloading load. Further, the first caulking portion 38 and the second caulking portion 48 are both provided with a groove, and a caulking tool is applied to the groove from the outer peripheral side of the outer cylinder 3. Therefore, the removal load of the seal case 27 and the retainer 29 can be further increased.

Next, the operation of the present embodiment configured as described above will be described.
In the cylinder device 1, the passage member 14 and the piston rod 6 are connected to the springs and unsprings of the wheels of the automobile, respectively, and the suspension device is connected to the connection port 15 of the passage member 14 and the connection port 24 of the connection member 21. Each of the external hydraulic circuits to be configured is connected.

  During the extension stroke of the piston rod 6, the hydraulic fluid on the cylinder chamber 2 </ b> A side is pressurized by the sliding of the piston 5 in the cylinder 2, and the notch 12, the annular passage 4, the opening 16, the opening 22, and the damping valve 19 It flows to the external hydraulic circuit through the orifice 26A, the disk valve 26 and the connection port 24. On the other hand, in the cylinder chamber 2 </ b> B that is depressurized by the sliding of the piston 5 in the cylinder 2, hydraulic fluid is supplied from an external hydraulic circuit connected to the connection port 15 of the passage member 14 through the check valve of the damping valve 13. Inflow. Thus, a damping force is generated by the orifice 26A of the damping valve 19 and the disk valve 26 with respect to the stroke of the piston rod 6, and a resistance force by an external hydraulic circuit acts.

  Further, during the contraction stroke of the piston rod 6, the hydraulic fluid on the cylinder chamber 2 B side is pressurized by the sliding of the piston 5 in the cylinder 2, and is connected to the connection port 15 of the passage member 14 through the damping mechanism of the damping valve 13. Flow to the external hydraulic circuit. On the other hand, in the cylinder chamber 2 </ b> A that is depressurized by sliding of the piston 5 in the cylinder 2, the check valve 25, the opening 22, and the opening 16 of the damping valve 19 are connected from an external hydraulic circuit connected to the connection port 24. The hydraulic fluid flows through the annular oil passage 4 and the notch 12. As a result, a damping force is generated by the damping mechanism of the damping valve 13 with respect to the stroke of the piston rod 6, and the resistance force of the external hydraulic circuit acts.

  At this time, for example, between the cylinder devices 1 mounted on the left and right wheels, the connection ports 24 and 15 are connected to an external hydraulic circuit having an accumulator to connect the cylinder chamber 2A and the cylinder chamber 2B to each other. Therefore, the reaction force by the accumulator is small for the stroke in the same direction (in-phase) of the hydraulic cylinders 1 of the left and right wheels, and the reaction force by the accumulator is large for the stroke in different directions (reverse phase). Therefore, the effect as a stabilizer which suppresses the posture change of the vehicle body at the time of turning can be obtained.

  During the operation of the cylinder device 1 described above, a very high pressure of about 35 MPa at the maximum acts on the seal portion S of the piston rod 6. The seal case 27 receiving this pressure is fitted with the outer circumferential groove 37 and the first caulking portion 38 of the outer cylinder 3 and with the outer circumferential groove 47 of the retainer 29 and the second caulking portion 48 of the outer cylinder 3. The first and second caulking portions 38 and 48 provided at two locations along the axial direction are firmly supported. The piston rod 6 is sealed in two stages by the rod seal 33 and the seal lip 35 of the oil seal 9. Thus, the pressure acting on the second-stage seal lip 35 accommodated in the recess 36 of the seal case 27 is reduced to about 4 MPa by the first-stage rod seal 33, and this is sealed by the seal lip 35. Become. As a result, the pressure strength of the seal portion S of the piston rod 6 can be significantly increased. Compared with the cylinder device of the prior art document mentioned above, in the prior art document, the pressure in the cylinder is applied to the entire rod guide surface of the cylinder end. Since the circumferential side is depressurized by the rod seal 33, the pressure applied to the first caulking portion 38 is the difference between the pressure in the cylinder and the pressure depressurized by the first stage rod seal 33. For example, If the inside of the cylinder is 35 MPa and the pressure reduced by the rod seal 33 is 31 MPa, a force of 4 MPa acts. Further, the pressure applied to the second caulking portion 48 is mainly the internal pressure in the recess 36. Thereby, since the pressure applied to the first caulking portion 38 and the second caulking portion 48 is a two-stage pressure, it is possible to improve both the durability against axial slip and the pressure resistance against radial expansion.

  Note that the slidability and sealing performance between the seal lip 35 and the piston rod 6 are enhanced by the hydraulic fluid that leaks from the rod seal 33 and accumulates in the recess 36. Further, the dust lip 45 prevents foreign matter from entering the sliding portion of the piston rod 6.

  The seal case 27 and the outer cylinder 3 are sealed by a first caulking portion 38 and O-rings 40 and seal members 43 provided on both sides in the axial direction, thereby enhancing resistance to high pressure. At this time, since the internal pressure acting on the first caulking portion 38 is blocked by the O-ring 40, expansion deformation due to the hoop stress of the first caulking portion 38 and the second caulking portion 48 is suppressed with respect to the internal pressure. It is possible to make it difficult for the seal case 27 to come off. Further, by caulking the seal case 27 close to the end of the cylinder 2, it is possible to increase the deflection remaining in the cylinder 2 after caulking, that is, the residual axial force becomes high, and the cylinder 2 has a higher resistance against rebound input. It is difficult for rattling to occur, and generation of abnormal noise from the cylinder 2 during traveling can be suppressed.

  As described above, the pressure strength of the seal portion S of the piston rod 6 can be significantly increased. Note that the O-ring 40 may be omitted if the necessary sealing performance against the internal pressure and the removal strength of the seal case 27 are obtained. In this case, since the pressure from the annular passage 4 acts on the first caulking portion 38 in the radial direction, the pressure resistance in the radial direction is not so high. However, the axial pressure with respect to the first caulking portion 38 is a differential pressure between the internal pressure of the recess 36 and the pressure of the annular passage 4 (for example, if the internal pressure of the recess 36 is 4 MPa and the pressure of the annular passage 4 is 35 MPa, 31 MPa In addition, the axial pressure on the second caulking portion 48 is equal to the pressure of the annular passage 4 corresponding to the area of the seal member 43 and the internal pressure of the recess 36, and therefore the shaft applied to each caulking portion as compared with the prior art. The force in the direction is reduced, the pull-out strength of the caulking portion is increased, and the pressure resistance can be greatly increased.

  Next, a second embodiment of the present invention will be described with reference to FIG. In the following description, the same reference numerals are used for the same parts with respect to the first embodiment shown in FIGS. 1 and 3, and only different parts will be described in detail.

  As shown in FIG. 2, a cylinder device 49 according to the present embodiment is an application of the present invention to a single cylinder type hydraulic shock absorber. The outer cylinder 3 also serves as the cylinder 2, and the cylinder 2 Omitted, the piston 5 is slidably inserted into the outer cylinder 3. Further, the damping valve 13 and the connection port 15 are omitted, the bottom of the outer cylinder 3 (cylinder) is closed, and a free piston (not shown) is inserted to form a gas chamber. A high pressure gas is sealed in the gas chamber.

  Further, the damping force generating mechanism 17 at the side of the outer cylinder 3 is omitted, and instead, the piston 5 is provided with expansion side and contraction side damping valves 50 and 51. The expansion side damping valve 50 controls the flow of hydraulic fluid from the cylinder chamber 2A side to the cylinder chamber 2B side to generate a damping force, and the contraction side damping valve is hydraulic fluid from the cylinder chamber 2B side to the cylinder chamber 2A side. The damping force is generated by controlling the flow.

  The rod guide 8 is press-fitted into the recess 30 of the seal case 27 and fixed. The retainer 29 is omitted, and the reinforcing plate 44 of the dust seal 28 is fixed by a caulking portion 52 in which an end portion of the outer cylinder 3 is caulked inward.

  With this configuration, the cylinder device 49, which is a single cylinder type hydraulic shock absorber, causes the cylinder chamber 2A side by sliding of the piston 5 in the outer cylinder 3 (cylinder) during the extension stroke of the piston rod 6. The hydraulic fluid is pressurized and flows to the cylinder chamber 2 </ b> B side through the extension side damping valve 50, and a damping force is generated by the extension side damping valve 50. Further, during the contraction stroke of the piston rod 6, the hydraulic fluid on the cylinder chamber 2 </ b> B side is pressurized and flows to the cylinder chamber 2 </ b> A side through the contraction side damping valve 51, and a damping force is generated by the contraction side damping valve 51. At this time, the volume change in the outer cylinder 3 (cylinder) accompanying the expansion and contraction of the piston rod 6 is compensated by the compression and expansion of the high-pressure gas in the gas chamber. And the seal | sticker part S of the piston rod 6 is raising the pressure-resistant intensity | strength significantly with respect to the pressure in the outer cylinder 2 (cylinder) similarly to the said 1st Embodiment.

  In the first and second embodiments, the case where the present invention is applied to a cylinder device that generates a damping force by being mounted on a suspension device of an automobile is exemplarily described. The present invention is not limited to this, and any other cylinder device can be used as long as it has a piston rod seal.

  DESCRIPTION OF SYMBOLS 1 Cylinder apparatus, 3 outer cylinder, 5 piston, 6 piston rod, 8 rod guide, 9 oil seal, 27 seal case, 33 rod seal, 37 outer periphery groove, 38 1st crimping part, 40 O-ring (outer periphery seal), 48 Second caulking part, S seal part

Claims (6)

An outer cylinder in which hydraulic fluid is sealed and at least one end opened, a piston inserted into the outer cylinder, a piston rod connected to the piston and projecting to the outside of the outer cylinder, and one end side in the outer cylinder An annular seal case provided on the outer periphery, an outer peripheral seal that seals between the outer cylinder and the seal case, an annular rod seal that is provided on the inner periphery of the seal case and slides on the piston rod, It consists of an annular oil seal that is provided on one end side of the seal case and slides with the piston rod,
The seal case is provided with an outer circumferential groove, and is fixed to the outer cylinder by a first caulking portion that caulks the outer cylinder from the outside into the outer circumferential groove, and the oil seal is a first caulking the outer cylinder from the outside. It is fixed to the outer cylinder by two caulking parts ,
The cylinder device according to claim 1, wherein the outer peripheral seal is disposed on both axial sides with respect to the first caulking portion . The oil seal is fixed by fitting an annular retainer on the axially outer side of the oil seal in the outer cylinder, and fixing the retainer to the outer cylinder by the second caulking portion. Item 4. The cylinder device according to Item 1 . Wherein the outer peripheral portion of the retainer, the grooves are provided, the second crimping portion, the cylinder device according to claim 2, characterized in that said being swaged into the groove. The cylinder device according to claim 3 , wherein the first caulking part and the second caulking part have the same shape. The cylinder device according to any one of claims 1 to 4 , wherein the cylinder device is a single cylinder type hydraulic shock absorber. The cylinder device according to any one of claims 1 to 4 , wherein the cylinder device has a double cylinder structure in which an outer cylinder is provided outside a cylinder into which the piston is slidably inserted.