JP2006138359A - Vehicular hydraulic shock absorber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydraulic shock absorber having reduced cost and weight by reducing the number of components while supporting a rod with high rigidity without causing tiling or fall-down relative to the axis of a cylinder, and preventing damage to the rod. <P>SOLUTION: The hydraulic shock absorber 1 comprises an annular stopper rubber 45 forming an annular gap between itself and the outer periphery of the rod 21, fitted through the outer periphery of a rod guide part 11D of the cylinder 11 and supported on a stepped portion continuously provided on the outer periphery of the rod guide part 11D, and a spring support 71 provided on the outer periphery of the rod 21. The spring support 71 has a stopper part 71A on which the stopper rubber 45 abuts and a cylindrical part 71B for restricting the diameter enlargement of the stopper rubber 45 when compressed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a hydraulic shock absorber for a vehicle.

  As a hydraulic shock absorber, as described in Patent Document 1, there is one in which a piston / rod assembly in which a piston is attached to a rod is slidably inserted into an oil chamber provided in a cylinder portion of a cylinder.

  In the hydraulic shock absorber of Patent Document 1, a rod guide is fitted to an inner periphery of an opening of a cylinder portion in a cylinder via an O-ring, and the rod is slidably supported on the rod guide.

The hydraulic shock absorber disclosed in Patent Document 1 has an annular stopper rubber fitted on the outer periphery of the rod, and an end cap with which the stopper rubber abuts is attached around the opening of the cylinder portion of the cylinder. A cylindrical portion for restricting the diameter expansion when compressed by the abutment with the end cap is provided on the spring receiver on the outer periphery of the rod.
JP2002-54677

  In the hydraulic shock absorber disclosed in Patent Document 1, the rod guide can be displaced in the radial direction with respect to the cylinder by the elastic component of the O-ring provided on the inner periphery of the opening of the cylinder portion in the cylinder. Therefore, when the rod moves back and forth in the cylinder, the rod axis may tilt or fall with respect to the cylinder axis, and the rod may be twisted. Further, since a large-diameter rod guide having substantially the same diameter as that of the cylinder portion of the cylinder is used, the cost is increased and the weight is increased, and the weight cannot be reduced.

  Further, in the hydraulic shock absorber disclosed in Patent Document 1, an annular stopper rubber is in close contact with the outer periphery of the rod, and dust tends to accumulate in an inner peripheral recess formed around the rod on the tip end side of the stopper rubber. For this reason, when the stopper rubber is compressed by sliding against the stopper and slides against the rod, dust accumulated in the inner peripheral recess of the stopper rubber rubs the outer periphery of the rod and scratches the outer periphery of the rod. easy.

  It is an object of the present invention to provide a hydraulic shock absorber that supports a rod with high rigidity without tilting or tilting with respect to the axis of the cylinder, preventing damage to the rod, reducing the number of parts, and reducing the weight. It is to plan.

  According to the first aspect of the present invention, there is provided a hydraulic shock absorber in which a piston / rod assembly having a piston attached to a rod is slidably inserted into an oil chamber provided in the cylinder portion of the cylinder. A rod guide portion having an inner and outer diameter smaller than that of the cylinder portion is integrally formed on the distal end side of the cylinder, and a bush is fitted in close contact with the inner periphery of the rod guide portion, and the rod is attached to the inner periphery of the bush. A seal that slides in contact with the inner periphery of the cylinder and the outer periphery of the rod is provided at a position inside the cylinder with respect to the bushing in the axial direction of the cylinder. An annular stopper rubber that forms an annular gap with the outer periphery is inserted into the outer periphery of the rod guide portion and supported by a stepped portion that continues to the outer periphery of the rod guide portion. Periphery of the spring receiving provided in a stopper portion said stopper rubber on receiving this spring abuts, is obtained by forming a cylindrical portion for regulating the diameter during compression of the stopper rubber.

  According to a second aspect of the present invention, in the first aspect of the present invention, the cylinder further integrally forms a seal mounting portion having an inner and outer diameter smaller than the cylinder portion on the tip end side in the axial direction of the cylinder portion. The rod guide portion is integrally formed on the tip end side in the axial direction of the mounting portion, and the bottom of the annular stopper rubber is connected to the outer periphery of the rod guide portion and the outer periphery of the rod guide portion. And a shape that matches the outer shape of the outer periphery of the seal mounting portion and a stepped portion provided continuously with the outer periphery of the seal mounting portion.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, a dust seal fitting portion is fitted on an outer periphery of a tip portion of the rod guide portion, and the annular stopper is fitted at the dust seal fitting portion. The inner periphery of the rubber is locked in the axial direction.

  The invention of claim 4 is the invention according to any one of claims 1 to 3, wherein the hydraulic shock absorber is an inverted type in which the cylinder is attached to the vehicle body side and the rod is attached to the wheel side. is there.

(Claim 1)
(a) The rod is supported in close contact with the inner periphery of the bush fitted in close contact with the rod guide portion formed integrally with the cylinder. Therefore, the rod is supported between the cylinder and without an elastic member or gap, and moves forward and backward in the cylinder without tilting in the axial direction of the cylinder. As a result, the rod does not tilt or fall with respect to the cylinder, the damper itself can be prevented from being bent, and the operability can be improved.

  (b) Since the rod guide part integrally formed on the tip side of the cylinder part serves as a rod guide, a special rod guide and a stopper ring for fixing the rod guide in the axial direction can be omitted, and the outer circumference of the rod guide The O-ring can be omitted, and the cost can be reduced.

  (c) The annular stopper rubber forms an annular gap with the outer periphery of the rod, does not slide against the rod, and does not scratch the outer periphery of the rod. Further, it is not necessary to provide an end cap on the cylinder, and the cost can be reduced and the weight can be reduced.

(Claim 2)
(d) The shape of the bottom of the annular stopper rubber is changed to the outer periphery of the rod guide portion, the step portion provided continuously with the outer periphery of the rod guide portion, the outer periphery of the seal attachment portion, and the step provided continuously with the outer periphery of the seal attachment portion. It was made to match the outer shape consisting of parts. That is, the shape of the bottom of the stopper rubber is matched with the outer shape of the tip of the cylinder, the pressure receiving area of the stopper rubber can be secured, and the most compressive load can be sufficiently buffered.

(Claim 3)
(e) Since the inner peripheral portion of the annular stopper rubber is locked by the dust seal fitting portion fitted to the outer periphery of the tip end side of the rod guide portion of the cylinder, the stopper rubber can be prevented from coming off.

(Claim 4)
(f) Since the hydraulic shock absorber is an inverted type, dust hardly accumulates on the outer periphery of the rod guide portion of the cylinder and the outer periphery of the rod, and the unsprung weight can be reduced.

  1 is an overall cross-sectional view showing a hydraulic shock absorber, FIG. 2 is an enlarged cross-sectional view of a main part of FIG. 1, and FIG. 3 is a cross-sectional view taken along line III-III of FIG.

  As shown in FIGS. 1 and 2, the hydraulic shock absorber 1 includes a cylinder assembly 10, a piston / rod assembly 20, a rod side mounting member 50, and a cylinder side mounting member 60. The hydraulic shock absorber 1 of the present invention is an inverted type in which the cylinder 11 of the cylinder assembly 10 is attached to the vehicle body side, and the piston rod 21 of the piston / rod assembly 20 is attached to the wheel side.

  The cylinder assembly 10 includes a cylinder 11 and a bush 12.

  The cylinder 11 is formed by casting an aluminum alloy or forging an aluminum alloy. In order to the axial tip end of the cylindrical cylinder portion 11A on which the piston 22 of the piston / rod assembly 20 slides, Rebound rubber mounting portion 11B having a smaller inner diameter than cylinder portion 11A and a thick wall, seal mounting portion 11C having an inner / outer diameter smaller than that of rebound rubber mounting portion 11B, and rod guide portion 11D having an inner / outer diameter smaller than that of seal mounting portion 11C. Are integrally formed. In the axial direction of the cylinder 11, a rebound rubber mounting portion 11B and a seal mounting portion 11C are provided between the cylinder portion 11A and the rod guide portion 11D.

  The bush 12 is formed of a cylindrical wound bush obtained by rounding a plate material, and is fitted to the inner periphery of the rod guide portion 11D of the cylinder 11 in close contact without an O-ring. The bush 12 supports the piston rod 21 in close contact with the piston rod 21 of the piston / rod assembly 20 without interposing a minute gap on the inner periphery thereof.

  The cylinder 11 includes a mounting screw 13 for the cylinder side mounting member 60 on the outer periphery of the rear end side of the cylinder portion 11A, and includes a bump stopper rubber mounting portion 14 on the outer periphery of the rebound rubber mounting portion 11B to the rod guide portion 11D. A hexagonal tool engagement portion 15 having a diameter smaller than the outer diameter of the cylinder portion 11A is provided on the outer periphery of the seal mounting portion 11C, and a dust seal attachment portion 16 is provided on the outer periphery of the tip portion of the rod guide portion 11D.

  The piston / rod assembly 20 has a piston 22 and a piston valve device (damping force generating device) 23 attached to a distal end side of a hollow piston rod 21 with a nut 24. In the piston valve device 23, a valve stopper 25, a pressure side plate valve 26, a piston 22, an extension side plate valve 27, and a valve stopper 28 are inserted in order into the piston rod 21, and these are fixed with a nut 24. An oil passage (not shown) and an extension side oil passage 27A are provided. The piston / rod assembly 20 is inserted into the cylinder portion 11A to the rod guide portion 11D of the cylinder 11 to project the piston rod 21 outward from the rod guide portion 11D, and the piston 22 is inserted into the oil chamber 29 of the cylinder portion 11A. The oil chamber 29 is slidably inserted, and the piston 22 divides the oil chamber 29 into a piston-side oil chamber 29A and a rod-side oil chamber 29B.

  The piston / rod assembly 20 incorporates a damping force adjusting device 31 in the hollow portion of the piston rod 21. The damping force adjusting device 31 is provided with a bypass oil passage 32 communicating with the piston side oil chamber 29A and the rod side oil chamber 29B inside the piston rod 21, and the needle at the tip of the adjustment rod 33 inserted into the hollow portion of the piston rod 21. The valve 33A adjusts the opening area of the valve seat 32A provided at the opening of the bypass oil passage 32 to the piston-side oil chamber 29A. The abutting portion 33B at the base end portion of the adjusting rod 33 protrudes from the piston rod 21 toward the rod side mounting member 50 and abuts on an extension side damping force adjusting adjuster 34 provided on the rod side mounting member 50. The adjuster 34 will be described later.

  In the piston / rod assembly 20, a rebound stopper rubber 41, a stopper plate 42, and an oil seal 43 are sequentially inserted on the outer periphery of the intermediate portion of the piston rod 21 inserted into the cylinder portion 11A to the rod guide portion 11D of the cylinder 11. To do. The rebound stopper rubber 41 is fitted into an annular groove formed on the inner periphery of the rebound rubber mounting portion 11B, and serves as a buffer at the time of maximum extension. The stopper plate 42 is press-fitted into the inner periphery of the rebound rubber mounting portion 11B of the cylinder 11, and is stopped by a step between the inner periphery of the rebound rubber mounting portion 11B and the inner periphery of the seal mounting portion 11C.

  The oil seal 43 is fitted to the inner periphery of the seal mounting portion 11C of the cylinder 11 and includes an inner peripheral lip that is in close contact with the outer periphery of the piston rod 21 and an outer peripheral lip that is in close contact with the inner periphery of the seal mounting portion 11C. The oil seal 43 is sandwiched and fixed in the axial direction between the step portion between the inner periphery of the seal mounting portion 11C and the inner periphery of the rod guide portion 11D and the stopper plate 42.

  In the piston / rod assembly 20, a dust seal 44 and a bump stopper rubber 45 are sequentially inserted on the outer periphery of the intermediate portion of the piston rod 21 protruding outward from the rod guide portion 11D. The dust seal 44 is fitted on the dust seal mounting portion 16 on the outer periphery of the rod guide portion 11 </ b> D of the cylinder 11 and is in sliding contact with the outer periphery of the piston rod 21. The bump stopper rubber 45 is fitted to the bump stopper rubber mounting portion 14 on the outer periphery of the rebound rubber mounting portion 11B to the rod guide portion 11D of the cylinder 11, and serves as a buffer at the time of maximum compression.

  The rod side mounting member 50 is fixed by being screwed onto the outer periphery of the proximal end portion of the piston rod 21. The rod side mounting member 50 is fitted with a spring receiver 71 of the suspension spring 70.

  The rod side mounting member 50 is provided with the above-described adjuster 34 screwed into the screw hole 51 </ b> A of the lateral hole 51. The adjuster 34 faces the grooved operation portion 34 </ b> A outward, and contacts the tapered cam surface 34 </ b> B with the contact portion 33 </ b> B of the adjustment rod 33. Accordingly, the adjuster 34 is rotated and screwed by an operation applied to the grooved operation portion 34A, and the adjustment rod 33 is advanced and retracted in the axial direction by the displacement of the cam surface 34B. As a result, the bypass valve 32A is bypassed by the needle valve 33A. The opening area of the valve seat 32A can be adjusted.

  The cylinder side mounting member 60 is screwed by fitting the outer cylinder portion 61 onto the mounting screw 13 on the outer periphery of the cylinder portion 11A on the rear end side (the side opposite to the rod guide portion 11D) of the cylinder 11 so that the cylinder portion 11A A cup-shaped bottom 62 that closes a straight opening having the same diameter as the piston 22 on the rear end side is integrally provided. The cylinder side mounting member 60 has a spring adjuster 72 for adjusting the initial load of the suspension spring 70 screwed onto the outer periphery of the outer cylinder part 61, and a spring receiver 73 backed up by the adjuster 72 is attached to the outer periphery of the outer cylinder part 61. The suspension spring 70 is supported between the spring receiver 73 and the aforementioned spring receiver 71 by engaging with a slide groove provided in the axial direction. A plate spring 74 for preventing rotation of the adjuster 72 is provided between the adjuster 72 and the spring receiver 73.

  As shown in FIG. 3, the cylinder side mounting member 60 includes a separator 81 at a communication portion between the oil chamber 84 </ b> A and the piston side oil chamber 29 </ b> A of the cylinder portion 11 </ b> A. . That is, the sub-tank 80 includes a gas sealing valve 85 that divides the interior sealed by the cap 82 into an oil chamber 84A and a gas chamber 84B by the partition member 83, and seals the pressurized gas in the gas chamber 84B. The separator 81 includes a pressure-side oil passage 86 and an extension-side oil passage 87 that connect the piston-side oil chamber 29A of the cylinder 11 and the oil chamber 84A of the sub tank 80, and the needle valve 88A of the pressure-side damping force adjustment adjuster 88 is used as the pressure-side oil. The extension side check valve 89 can be inserted into the passage 86 and the extension side oil passage 87 is provided. At this time, the cylinder side mounting member 60 is screwed into the opening 63 into which the separator 81 is inserted through the cap 64 via the O-ring 64A, and the adjuster 88 is screwed into the cap 64 via the O-ring 88A in a liquid-tight manner. is doing. The adjuster 88 is screwed into the cap 64 to move forward and backward, and the opening area of the pressure side oil passage 86 is adjusted by the needle valve 88A.

  Hereinafter, the bump stopper rubber 45 fitted to the bump stopper rubber mounting portion 14 on the outer periphery of the rebound rubber mounting portion 11B to the rod guide portion 11D of the cylinder 11 will be described in detail.

  The bump stopper rubber 45 has an annular shape and forms an annular gap between the bump stopper rubber 45 and the outer periphery of the piston rod 21 while being fitted to the bump stopper rubber mounting portion 14 of the cylinder 11. The bump stopper rubber 45 is inserted into the rod guide portion 11D of the cylinder 11 and supported by a stepped portion provided continuously with the outer periphery of the rod guide portion 11D. Specifically, the bump stopper rubber 45 has an inner peripheral shape of the bottom portion 45A, an outer periphery of the rod guide portion 11D, a stepped portion connected to the outer periphery of the rod guide portion 11D and the outer periphery of the seal mounting portion 11C, The outer shape of the seal mounting portion 11C, the outer shape of the seal mounting portion 11C, and a stepped portion connected to the outer periphery of the rebound rubber mounting portion 11B, are fitted into the outer shape.

  The spring receiver 71 fitted to the rod side mounting member 50 screwed and fixed to the outer periphery of the base end portion of the piston rod 21 is integrally formed with a stopper portion 71A that abuts the tip portion 45B of the bump stopper rubber 45. In addition, a cylindrical portion 71 </ b> B that restricts the diameter expansion of the bump stopper rubber 45 during compression is integrally provided. Thereby, the number of parts can be reduced.

  The fitting portion 44A of the dust seal 44 fitted to the dust seal attachment portion 16 on the outer periphery of the tip end portion of the rod guide portion 11D is formed with the inner peripheral portion of the bottom portion 45A of the bump stopper rubber 45 and the shaft. The bump stopper rubber 45 is prevented from coming off.

Therefore, the hydraulic shock absorber 10 performs a damping action as follows.
(When compressed)
The oil in the piston-side oil chamber 29A flows into the rod-side oil chamber 29B through the pressure-side oil passage, and this oil deflects and deforms the pressure-side plate valve 26 to obtain a pressure-side damping force. Following this, the oil corresponding to the volume of the piston rod 21 that has entered the cylinder 11 becomes surplus, and this surplus oil passes from the piston side oil chamber 29A through the pressure side oil passage 86 of the separator 81 to the oil chamber 84A of the sub tank 80. During this time, the compression side damping force is obtained by the throttle resistance by the needle valve 88A.

(When stretched)
When the relative speed between the cylinder 11 and the piston rod 21 is low, the oil in the rod side oil chamber 29B passes through the bypass oil passage 32 of the piston rod 21 whose opening is adjusted by the needle valve 33A of the adjustment rod 33, and the piston side oil. It flows into the chamber 29A, and the expansion side damping force is obtained by the throttle resistance by the needle valve 33A during this period. Further, when the relative speed between the cylinder 11 and the piston rod 21 is medium to high, the oil in the rod side oil chamber 29B passes through the extension side oil passage 27A and bends and deforms the extension side plate valve 27 to flow to the piston side oil chamber 29A. Get the extension damping force. At this time, the oil corresponding to the retraction volume of the piston rod 21 retreating from the cylinder 11 is insufficient, and this insufficient oil passes from the oil chamber 84A of the sub tank 80 to the piston side oil chamber 29A through the extension side oil passage 87 of the separator 81. It is replenished promptly.

  The expansion and contraction vibration of the hydraulic shock absorber 10 is suppressed by the damping force on the compression side and the extension side.

  When the hydraulic shock absorber 10 is most compressed, a buffer action at the time of the most compression is achieved by abutment between the bump stopper rubber 45 on the cylinder 11 side and the stopper portion 71A provided on the spring receiver 71 on the piston rod 21 side. . When the hydraulic shock absorber 10 is fully extended, the rebound stopper rubber 41 on the cylinder 11 side and the valve stopper 25 on the piston rod 21 abut against each other to provide a buffering action when fully extended.

According to the present embodiment, the following operational effects can be obtained.
(a) The piston rod 21 is supported in close contact with the inner periphery of the bush 12 fitted in close contact with the rod guide portion 11D formed integrally with the cylinder 11. Therefore, the piston rod 21 is supported between the cylinder 11 without an elastic member or a gap, and moves forward and backward in the cylinder 11 without tilting in the axial direction of the cylinder 11. As a result, the piston rod 21 is not tilted or tilted with respect to the cylinder 11, and the bending of the damper itself can be prevented and the operability can be improved.

  (b) Since the rod guide portion 11D integrally formed on the tip end side of the cylinder portion 11A serves as a rod guide, a special rod guide and a stopper ring for fixing the rod guide in the axial direction can be omitted. The O-ring on the outer periphery of the can be omitted, and the cost can be reduced.

  (c) The annular bump stopper rubber 45 forms an annular gap with the outer periphery of the piston rod 21, does not slide with respect to the piston rod 21, and does not scratch the outer periphery of the piston rod 21. . Further, it is not necessary to provide an end cap on the cylinder 11, which can reduce cost and weight.

  (d) The bottom 45A of the annular bump stopper rubber 45 has the shape of the outer periphery of the rod guide portion 11D, the step portion connected to the outer periphery of the rod guide portion 11D, the outer periphery of the seal mounting portion 11C, and the seal mounting portion 11C. It was made to match the external shape which consists of the step part provided in a line with the outer periphery. That is, the shape of the bottom 45A of the bump stopper rubber 45 is matched to the outer shape of the tip end side of the cylinder 11, the pressure receiving area of the bump stopper rubber 45 can be secured, and the most compressive load can be sufficiently buffered.

  (e) Since the inner peripheral portion of the annular bump stopper rubber 45 is locked by the fitting portion 44A of the dust seal 44 fitted on the outer periphery of the rod guide portion 11D of the cylinder 11, the bump stopper rubber 45 is removed. Can be prevented.

  (f) Since the hydraulic shock absorber 1 is an inverted type, dust hardly accumulates on the outer periphery of the rod guide portion 11D of the cylinder 11 and the outer periphery of the piston rod 21, and the unsprung weight can be reduced.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration of the present invention is not limited to this embodiment, and even if there is a design change or the like without departing from the gist of the present invention. It is included in the present invention.

FIG. 1 is an overall cross-sectional view showing a hydraulic shock absorber. FIG. 2 is an enlarged cross-sectional view of the main part of FIG. FIG. 3 is a sectional view taken along line III-III in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hydraulic buffer 11 Cylinder 11A Cylinder part 11C Seal mounting part 11D Rod guide part 12 Bushing 20 Piston / rod assembly 21 Piston rod (rod)
22 Piston 29 Oil chamber 43 Oil seal (seal)
44 Dust seal 45 Bump stopper rubber 71 Spring receiver 71A Stopper part 71B Tubular part

Claims (4)

In a hydraulic shock absorber in which a piston / rod assembly in which a piston is attached to a rod is slidably inserted into an oil chamber provided in a cylinder portion of the cylinder,
A rod guide portion having an inner and outer diameter smaller than that of the cylinder portion is integrally formed on the distal end side in the axial direction with respect to the cylinder portion of the cylinder,
Fit the bush in close contact with the inner periphery of the rod guide part,
Supporting the rod in close contact with the inner periphery of the bush,
A seal that is in sliding contact with the inner periphery of the cylinder and the outer periphery of the rod is provided at a position on the inner side in the axial direction of the cylinder with respect to the bush inside the cylinder.
An annular stopper rubber that forms an annular gap with the outer periphery of the rod is inserted into the outer periphery of the rod guide portion, and supported by a stepped portion that is connected to the outer periphery of the rod guide portion,
The vehicle is characterized in that a spring receiver is provided on the outer periphery of the rod, and a stopper portion with which the stopper rubber abuts is formed on the spring receiver, and a cylindrical portion that restricts the diameter expansion of the stopper rubber when compressed. Hydraulic shock absorber. The cylinder is integrally formed with a seal mounting portion having an inner and outer diameter smaller than the cylinder portion on the tip end side in the axial direction of the cylinder portion, and the rod guide portion is disposed on the tip end side in the axial direction of the seal mount portion. Formed integrally,
The bottom portion of the annular stopper rubber is connected to the outer periphery of the rod guide portion, the step portion connected to the outer periphery of the rod guide portion, the outer periphery of the seal mounting portion, and the step connected to the outer periphery of the seal mounting portion. The hydraulic shock absorber for a vehicle according to claim 1, wherein the hydraulic shock absorber has a shape matched to an outer shape including a portion.   The dust seal fitting portion is fitted on the outer periphery of the tip end portion of the rod guide portion, and the inner circumferential portion of the annular stopper rubber is locked in the axial direction by the dust seal fitting portion. Hydraulic shock absorber for vehicle as described in 2.   The hydraulic shock absorber for a vehicle according to any one of claims 1 to 3, wherein the hydraulic shock absorber is an inverted type in which the cylinder is attached to a vehicle body side and the rod is attached to a wheel side.

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