JP2005226734A - Vehicular shock absorber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicular shock absorber having simple construction with an inexpensive air vent passage. <P>SOLUTION: In the vehicular shock absorber 10, an inner tube 12 is inserted into an outer tube 11 via a sliding guide tube 13 provided in an opening portion of the outer tube 11. On the outer periphery at the upper end of the inner tube 12, a piston 14 is provided for sliding in the outer tube 11. The piston 14 partitions two air chambers 15A, 15B from each other on the upper and lower sides. Cylindrical spring supports 21, 22 are provided at the upper end of the inner tube 12 and at the upper part of the outer tube 11, respectively. A suspension spring 23 is wound at its upper and lower ends on the outer peripheries of the cylindrical spring supports 21, 22, respectively. The air vent passage 31 is formed in the spring support 21 at the upper end of the inner tube 12, and the upper air chamber 15A of the piston 14 is communicated with the outside via the air vent passage 31 and the inside of the inner tube 12. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention inserts an inner tube into the outer tube via a sliding guide tube provided in the opening of the outer tube, and provides a piston that slides in the outer tube on the outer periphery of the upper end portion of the inner tube. The present invention relates to a shock absorber for a vehicle in which two air chambers are partitioned on the upper and lower sides of the piston.

  A front wheel shock absorber used for a small displacement scooter is provided with a piston made of a hard synthetic resin such as Duracon (registered trademark) on the outer periphery of the tip of the inner tube on the wheel side in terms of cost. In addition, a sliding guide tube made of hard synthetic resin such as Duracon (registered trademark) is provided on the inner periphery of the opening of the outer tube on the vehicle body side, and the inner tube on the wheel side is guided by this piston and the sliding guide tube, A simple shock absorber (so-called grease damper) filled with lubricating grease is attached between the outer periphery of the piston and the inner periphery of the outer tube and between the inner periphery of the sliding guide tube and the inner tube.

  This shock absorber generates a damping force by the friction between the piston and the outer tube, and the inner tube and the sliding guide tube, and also between the piston and the outer tube and keeps a proper lubrication. Lubricating grease is filled between the guide tube and the inner tube.

  As the inner tube advances and retreats into the outer tube, the upper and lower air chambers defined by the piston in the outer tube are compressed and expanded.

  In such a shock absorber, in particular, when the sliding guide cylinder and the piston are formed of synthetic resin, the outer tube is provided between the inner tube and the sliding guide cylinder in anticipation of the temperature expansion of the sliding guide cylinder and the piston. A relatively large clearance is provided between the piston and the piston. Although grease is applied to the inner periphery of the sliding guide tube or the outer periphery of the piston, it is not sealed. As a result, the lower air chamber of the piston in the outer tube is in communication with the outside air to some extent, and the upper and lower air chambers of the piston in the outer tube are also in communication.

  As a result, in particular, in an inverted shock absorber in which the outer tube is attached to the vehicle body and the inner tube is attached to the axle, mud tends to adhere to the inner tube, but the upper air chamber in the outer tube expands during the extension stroke. When this occurs, the negative pressure or reduced pressure of the upper air chamber sucks this mud into the inner periphery of the sliding guide cylinder through the lower air chamber, and the sliding surfaces of the sliding guide cylinder and the inner tube are damaged. is there.

  Further, in Patent Document 1, a small hole that communicates the inside of the buffer cylinder and the outside air is provided, and air in the buffer cylinder that is compressed and expanded by the vertical movement of the shock absorber is caused to enter and exit from the small hole to provide a buffering action. Alternatively, a technique for completely eliminating ventilation resistance is disclosed.

In addition, in the shock absorber of Patent Document 1, a buffer spring 11 that cushions the bottom in the extension direction is provided, but without using such a buffer spring 11, both ends of the suspension spring are connected to the outer tube side and the inner tube. A type of shock absorber is also known that is wound around a cylindrical spring receiver on the side and fixed, and the bottom of the extending direction is buffered by this suspension spring.
Jikosho 57-19358

  The present invention inserts an inner tube into the outer tube via a sliding guide tube provided in the opening of the outer tube, and provides a piston that slides in the outer tube on the outer periphery of the upper end portion of the inner tube. The piston separates two air chambers at the top and bottom of the piston in the outer tube, and a cylindrical spring receiver is fixed to each of the upper end portion of the inner tube, the outer tube and the upper portion, and each of the cylindrical spring receivers is fixed. An object of the present invention is to provide a shock absorber for a vehicle in which each end of a suspension spring is wound around the outer periphery, and has a simple structure and an inexpensive air vent passage.

  According to the first aspect of the present invention, an inner tube is inserted into the outer tube via a sliding guide tube provided in an opening of the outer tube, and the inner tube is slid on the outer periphery of the upper end portion of the inner tube. A piston that moves, the piston defines two air chambers above and below the piston, and a cylindrical spring support is provided on each of an upper end portion of the inner tube and an upper portion of the outer tube; In a vehicle shock absorber in which upper and lower ends of a suspension spring are wound around the outer periphery of each of the spring springs, an air vent passage is formed in the spring receiver at the upper end of the inner tube, The air chamber communicates with the outside through the air vent passage and the inside of the inner tube.

  According to a second aspect of the present invention, in the first aspect of the present invention, a hollow portion is formed in the spring receiver at the upper end portion of the inner tube, and a communication portion that communicates the inner and outer circumferences is formed at the upper end portion. The air vent passage is formed by the communication portion.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the upper air chamber of the piston is communicated with the outside through a drain hole provided in a lower portion of the inner tube.

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, a bump rubber is provided on a spring receiver at an upper end portion of the inner tube via a synthetic resin collar, and the bump rubber is attached to the outer rubber. It is made to collide with the end face of the spring receiver provided in the upper part of the tube.

  According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, an air vent passage is formed between the spring receiver on the outer tube side and a cap provided at an upper end portion of the outer tube. The upper air chamber of the piston communicates with the outside through the air vent passage.

(Claim 1)
a. "When the shock absorber is extended, an air vent passage is formed in the spring receiver at the upper end of the inner tube, and the upper air chamber of the piston is communicated with the outside through the air vent passage and the inner tube." When the inner tube is withdrawn from the outer tube, the upper air chamber of the piston in the outer tube expands and depressurizes, but the air from the spring receiver is released from the drain hole at the bottom of the inner tube or the clearance of the axle mounting portion at the tip. Outside air is supplied to the upper air chamber in the outer tube via the passage.

  As a result, the upper and lower air chambers of the piston in the outer tube will not be depressurized, and mud etc. will not be sucked into the inner peripheral surface of the sliding guide tube provided on the inner periphery of the open end of the outer tube.

(Claim 2)
b. Since “the air vent passage is formed by the hollow portion and the communication portion of the spring receiver”, the pressure reduction in the shock absorber can be prevented with a simple structure in which the hollow portion and the communication portion are formed in the spring receiver. In addition, since the cylindrical spring receiver is formed by zinc die casting, it does not require additional processing man-hours, and the cost can be reduced and the weight can be reduced by reducing the amount of material used. .

(Claim 3)
c. “The upper air chamber of the piston is made to reach the outside through the drain hole provided in the lower part of the inner tube”, so that the existing water for discharging the water accumulated in the inner tube due to condensation in the inner tube is discharged. Since the air vent passage is formed using the water drain hole, it is not necessary to process the air vent passage separately. Therefore, the air vent passage can be formed at a low cost without causing an increase in cost.

(Claim 4)
d. Bump rubber is provided on the spring receiver on the upper end of the inner tube via a synthetic resin collar, and this bump rubber is brought into contact with the end face of the spring receiver provided on the upper part of the outer tube. The rubber abuts against the end face of the spring receiver on the outer tube side to provide a buffer during maximum compression. Further, the collar made of synthetic resin defines an air vent passage between the upper end surface of the inner tube spring receiver and also serves as a guide for the suspension spring.

(Claim 5)
e. “By providing an air vent passage between the spring receiver on the outer tube side and the cap provided at the upper end of the outer tube”, the spring receiver and the cap fixed to the inner periphery of the upper end of the outer tube A gap is provided between them, and this gap can be added as an air vent passage to increase the pressure reducing effect of the air chamber in the outer tube.

  1 is a front view showing the shock absorber partially broken, FIG. 2 is a cross-sectional view showing the suspension spring support structure of FIG. 1, FIG. 3 is a cross-sectional view showing the lower spring support, and FIG. FIG. 5 shows a lower spring receiver, (A) is a sectional view, (B) is a side view, FIG. 6 shows an upper spring receiver, (A) is a sectional view, (B) is a plan view, (C) is a side view, FIG. 7 is a sectional view showing the periphery of the sliding guide tube of FIG. 1, FIG. 8 is a perspective view of the sliding guide tube, FIG. 9 shows the sliding guide tube, and (A) is a front view. FIG. 5B is a cross-sectional view taken along line BB, and FIG. 5C is a cross-sectional view taken along line CC.

  A shock absorber 10 in FIG. 1 is used as a front wheel shock absorber such as a small displacement scooter, and an outer tube 11 on the vehicle body side is attached to a steering shaft 1 supported on the vehicle body side via upper and lower brackets 2 and 3. It is. The shock absorber 10 is provided with a sliding guide tube 13 made of a hard synthetic resin such as engineering plastic such as Duracon (trademark of Polyplastics) on the inner periphery of the opening of the outer tube 11, and the inner tube inserted into the outer tube 11. 12 is guided by the sliding guide tube 13.

  Further, as shown in FIG. 2, the shock absorber 10 is provided with a synthetic resin piston 14 that slides on the inner periphery of the outer tube 11 on the outer periphery of the upper end portion of the inner tube 12. 11, two air chambers 15A and 15B are defined above and below the piston 14.

  The shock absorber 10 includes a piston 14 provided on the outer periphery of the distal end portion of the inner tube 12, an inner periphery of the outer tube 11, an inner periphery of the sliding guide tube 13 provided on the outer tube 11, and an outer periphery of the inner tube 12. A grease damper filled with lubricating grease is formed between them. That is, the shock absorber 10 generates a damping force due to the friction between the outer periphery of the piston 14 and the inner periphery of the outer tube 11 and the friction between the inner tube 12 and the sliding guide cylinder 13, and the outer periphery of the piston 14 and the inner tube 11. The proper lubrication is maintained by the grease filled between the circumference and the inner tube 12 and the sliding guide tube 13.

  The shock absorber 10 abuts the base end large-diameter portion 13A of the sliding guide tube 13 inserted into the inner periphery of the opening portion of the outer tube 11 against the step portion on the inner periphery of the opening end large-diameter portion of the outer tube 11, The backup ring 15 seated on the end surface of the base end large diameter portion 13A is locked by a stopper ring 16 engaged with the inner periphery of the large diameter portion of the open end of the outer tube 11, and the open end of the outer tube 11 is closed. The dust seal 17 is attached to the outer periphery of the large diameter portion, and the oil seal lip 17A and the dust seal lip 17B of the dust seal 17 are brought into close contact with the outer periphery of the inner tube 12 (FIG. 7).

  The shock absorber 10 is provided with cylindrical spring receivers 21 and 22 on the upper end portion of the inner tube 12 and the upper portion of the outer tube 11, respectively, and each end of the suspension spring 23 is arranged on the outer periphery of the spring receivers 21 and 22. Each part is wound and attached.

  Hereinafter, (A) an air vent structure for the upper air chamber 15A of the outer tube 11 and (B) a grease circulation structure of the sliding guide cylinder 13 will be described.

(A) Air vent structure for the upper air chamber 15A of the outer tube 11 As shown in FIG. 3, the shock absorber 10 forms an air vent passage 31 in the lower spring receiver 21 at the upper end portion of the inner tube 12, and the piston 14 The upper air chamber 15 </ b> A communicates with the outside through the air vent passage 31 and the inner tube 12.

  As shown in FIG. 5, the spring receiver 21 inserts the lower fitting shaft 33 of the annular flange 32 into the upper end inner diameter portion of the inner tube 12, abuts the flange 32 against the upper end surface of the inner tube 12, and the flange 32. The lower end portion of the suspension spring 23 is wound around a spiral groove 34A provided in a part in the circumferential direction of the upper spring winding portion 34 (two arc portions opposed in the diameter direction).

  The spring receiver 21 forms a hollow portion 31A extending over the entire length of the fitting shaft 33 to the spring winding portion 34, and communicates the inner and outer circumferences with the upper end surface of the fitting shaft 33 facing the upper air chamber 15A of the outer tube 11. A groove-like communication part 31B (or a hole-like communication part is acceptable) is formed, and the air vent passage 31 is formed by the hollow part 31A and the communication part 31B. The upper air chamber 15 </ b> A of the outer tube 11 is connected to an air vent passage 31 (hollow portion 31 </ b> A, communication portion 31 </ b> B) of the spring receiver 21, a drain hole 12 </ b> A provided in the inner tube 12, and a lower portion of the inner tube 12. Communicate to the outside.

  In addition, 12B is a guide stay of a brake wire, 12C is a stay for protector attachment, 12D is a brake stopper, and each is fixed to the outer periphery of the lower part of the inner tube 12 by welding.

  A metal collar 24 having a smaller outer diameter than the inner periphery of the outer tube 11 is attached to the upper outer periphery of the inner tube 12, and the fitting shaft 33 of the spring receiver 21 inserted into the upper end inner diameter portion of the inner tube 12, and the inner A fixing pin 25 is inserted like a skewer into a through hole provided in each of the tube 12 and the collar 24. The spring receiver 21 is fixed in both the axial direction and the rotational direction by the fixing pin 25 with the flange 32 abutted against the upper end surface of the inner tube 12. The piston 14 is fitted on the outer periphery of the upper end portion of the inner tube 12 and is sandwiched between the flange 32 of the spring receiver 21 and the collar 24. An annular recess into which the flange 32 is fitted is formed on the upper end surface of the piston 14, and the lower end surface of the piston 14 is seated on the upper end surface of the collar 24.

  A bump rubber 27 is provided on the upper end surface of the spring receiver 21 via a collar 26 made of synthetic resin. The bump rubber 27 abuts on the end surface of the upper spring receiver 22 and makes it possible to regulate the maximum compression stroke of the outer tube 11 and the inner tube 12.

  As shown in FIG. 4, the shock absorber 10 has the outer periphery of the cap 28 fixed to the upper end portion of the outer tube 11 by welding, and the upper spring receiver 22 on the upper portion of the outer tube 11 is supported on the back surface of the cap 28. An air vent passage 41 is formed between the upper spring receiver 22 and the cap 28, and the upper air chamber 15 </ b> A of the outer tube 11 communicates with the outside through the air vent passage 41.

  As shown in FIG. 6, the spring receiver 22 includes a protrusion 43 </ b> A provided on a part of the outer periphery of the head 43 by inserting the upper head 43 of the annular flange 42 into the inner diameter of the cap 28 via a gap 41 </ b> A. Is engaged with an anti-rotation recess 28A (not shown) provided on the inner periphery of the cap 28 to prevent the rotation. Further, the spring receiver 22 has a circumferential portion of the spring winding portion 44 at the lower portion of the flange 42 (two arc portions opposed in the diameter direction) in a state where the flange 42 is abutted against the lower end surface of the cap 28. The upper end portion of the suspension spring 23 is wound around the provided spiral groove 44A.

  The spring receiver 22 extends radially outward from the outer peripheral side of the head 43 at a plurality of circumferential positions (for example, three positions) on the upper surface of the flange 42, and on the outer periphery of the flange 42 facing the inner periphery of the outer tube 11. A vent groove 41B is provided. The spring receiver 22 forms an air vent passage 41 by the gap 41A and the ventilation groove 41B. The upper air chamber 15A of the outer tube 11 communicates with the outside through an air vent passage 41 (gap 41A, ventilation groove 41B) of the spring receiver 22.

  A fixing screw 4 inserted through the upper bracket 2 is screwed to the center of the head 43 to the spring winding portion 44 of the spring receiver 22, and the upper bracket 2 is fixed to the upper end surface of the cap 28 of the outer tube 11. Is done.

  In addition, the mounting tube 11A is welded and fixed to a part (intermediate portion) of the outer tube 11 in the axial direction, and the lower bracket 3 is welded and fixed to the intermediate portion of the outer periphery of the mounting tube 11A. The presence of the attachment tube 11 </ b> A prevents welding distortion for attaching the lower bracket 3 to the outer tube 11 on the inner periphery of the outer tube 11 on which the piston 14 slides.

  The suspension spring 23 wound around each of the lower spring receiver 21 and the upper spring receiver 22 functions as a rebound spring that regulates the maximum extension stroke of the outer tube 11 and the inner tube 12, and at the time of maximum extension, the sliding guide cylinder. 13 prevents the upper end surface of 13 from colliding with the lower end surface of the collar 26.

Therefore, according to the present embodiment, the following operational effects can be obtained.
a. “By forming an air vent passage 31 in the spring receiver 21 at the upper end of the inner tube 12 and allowing the upper air chamber 15A of the piston 14 to communicate with the outside via the air vent passage 31 and the inner tube 12” When the inner tube 12 is retracted from the outer tube 11 when the shock absorber 10 is extended, the upper air chamber 15A of the piston 14 in the outer tube 11 expands and depressurizes. Outside air is replenished to the upper air chamber 15 </ b> A in the outer tube 11 through the air vent passage 31 of the spring receiver 21 from the gap of the axle mounting portion at the tip.

  As a result, the upper and lower air chambers 15 and 15B of the piston 14 in the outer tube 11 are not depressurized, and mud or the like is formed on the inner peripheral surface of the sliding guide cylinder 13 provided on the inner periphery of the open end of the outer tube 11. No longer inhale.

  b. Since the air vent passage 31 is formed by the hollow portion 31A and the communication portion 31B of the spring receiver 21, the pressure reduction in the shock absorber 10 can be achieved with a simple structure in which the hollow portion 31A and the communication portion 31B are formed in the spring receiver 21. Can be prevented. In addition, since the cylindrical spring receiver 21 is formed by zinc die casting, it does not require additional processing man-hours, and the cost can be reduced by reducing the amount of material used. Become.

  c. By “the upper air chamber 15A of the piston 14 is made to reach the outside through the drain hole 12A provided in the lower part of the inner tube 12”, the water accumulated in the inner tube 12 due to condensation in the inner tube 12 or the like. Since the air vent passage 31 is formed using the existing drain hole 12A for discharging, it is not necessary to process the air vent passage 31 separately. Therefore, the air vent passage 31 can be formed at a low cost without causing an increase in cost.

  d. “Bump rubber 27 is provided on the spring receiver 21 at the upper end of the inner tube 12 via a collar 26 made of synthetic resin, and this bump rubber 27 is brought into contact with the end face of the spring receiver 21 provided on the upper portion of the outer tube 11. By doing so, the bump rubber 27 abuts against the end face of the spring receiver 22 on the outer tube 11 side, thereby buffering at the time of maximum compression. The collar 26 made of synthetic resin defines an air vent passage 31 between the upper end surface of the spring receiver 21 on the inner tube 12 side and also serves as a guide for the suspension spring 23.

  e. “The air vent passage 41 is provided between the spring receiver 22 on the outer tube 11 side and the cap 28 provided at the upper end portion of the outer tube 11”, whereby the inner circumference of the upper end portion of the spring receiver 22 and the outer tube 11 is provided. A gap 41A is provided between the cap 28 and the cap 28, and the gap 41A is added as an air vent passage 41, so that the pressure reducing effect of the air chambers 15A and 15B in the outer tube 11 can be increased.

(B) Grease circulation structure of the sliding guide tube 13 As shown in FIG. 7, the shock absorber 10 allows the inner tube 12 to slide freely on the sliding guide tube 13 provided on the inner periphery of the opening of the outer tube 11. invite.

  As shown in FIGS. 8 and 9, the sliding guide tube 13 is provided with a grease reservoir hole 51 communicating with the inner and outer circumferences in the axial intermediate portion, and the grease loaded in the grease reservoir hole 51 is disposed on the outer periphery of the inner tube 12. Adhere. On the inner periphery of both the upper and lower ends in the axial direction of the sliding guide tube 13, there are provided upper and lower annular seal members 60 slidably contacting the outer periphery of the inner tube 12, for example, O-rings, and the outer tube 11 and the inner tube 12. During the expansion / contraction stroke, the grease adhering to the outer periphery of the inner tube 12 is scraped off by the seal member 60. The grease on the inner side in the axial direction of the seal member 60 scraped off by the upper and lower seal members 60 passes through the outer periphery of the sliding guide cylinder 13 through the upper and lower circulation paths 53 as shown by arrows in FIG. 51 is communicated.

  Specifically, the sliding guide tube 13 is formed with upper and lower inner peripheral grooves 52 and 52 into which the upper and lower seal members 60 are fitted on the inner periphery of the upper and lower ends in the axial direction. The grease on the inner side in the axial direction of the sealing member 60 is accumulated in the inner circumferential grooves 52. The sliding guide cylinder 13 is formed with upper and lower circulation holes 53A communicating with the inner and outer circumferences of the sliding guide cylinder 13 in the axially inner portion of the seal member 60 in each inner circumferential groove 52, and each circulation hole 53A. The upper and lower circulation grooves 53 </ b> B extending in the axial direction so as to communicate with the grease reservoir hole 51 are formed on the outer periphery of the sliding guide cylinder 13. A circulation path 53 is constituted by the circulation hole 53A and the circulation groove 53B.

  Furthermore, the sliding guide tube 13 forms a wide annular outer peripheral groove 54 in which the grease reservoir hole 51 is opened on the outer periphery of the intermediate portion in the axial direction. A plurality of circulation holes 53 </ b> A communicating the inner and outer circumferences of the sliding guide cylinder 13 are formed in the inner peripheral grooves 52 at both the upper and lower ends of the sliding guide cylinder 13. A plurality of circulation grooves 53B that communicate the plurality of circulation holes 53A with the annular outer circumferential groove 54 are formed in the axial direction.

Therefore, according to the present embodiment, the following operational effects can be obtained.
a. “An annular seal member 60 slidably contacting the outer periphery of the inner tube 12 is provided on the inner periphery of both end portions in the axial direction of the sliding guide tube 13, and grease on the inner side in the axial direction of the seal member 60 is applied to the sliding guide tube 13. The circulation path 53 communicating with the grease reservoir hole 51 is formed via the outer periphery of the sliding guide cylinder 13 ”, whereby the grease adhering to the outer periphery of the inner tube 12 is scraped off by the annular seal member 60, Leakage to the outside of the moving guide cylinder 13 in the axial direction is prevented. Further, the scraped grease passes through the hole 53A of the circulation path 53 formed on the inner side in the axial direction of the seal member 60, is pushed out to the outer peripheral side, and further passes through the outer periphery of the sliding guide tube 13 to be grease. Return to the pool hole 51. That is, the grease circulates through the circulation path 53 of the sliding guide cylinder 13 to the grease reservoir hole 51 and prevents the grease from leaking outside as much as possible.
Therefore, the life of the shock absorber can be extended with a simple and inexpensive configuration.

  b. “An annular inner circumferential groove 52 into which the annular sealing member 60 is fitted is formed at both ends of the sliding guide tube 13, and the sliding is performed on the axially inner side of the sealing member 60 in the inner circumferential groove 52. A circulation hole 53A that connects the inner and outer circumferences of the guide cylinder 13 is formed, and a circulation groove 53B that communicates the circulation hole 53A with the grease reservoir hole 51 is formed on the outer periphery of the sliding guide cylinder 13, and the circulation hole 53A and the circulation groove 53B are formed. The grease on the outer periphery of the inner tube 12 scraped off by the seal member 60 is accumulated in the annular inner peripheral groove 52, and further from the circulation hole 53A on the axially inner side of the seal member 60 to the outer peripheral side. To the grease reservoir hole 51 through the circulation groove 53B on the outer periphery.

  As a result, the grease can be held also in the inner circumferential groove 52, so that the seal member 60 is lubricated and a plurality of lubrication points are provided, so that the slidability is increased. Also, grease circulation is ensured.

  c. “On the outer periphery of the sliding guide tube 13, an annular outer peripheral groove 54 in which the grease retaining hole 51 is opened is formed, and a plurality of circulation holes 53 </ b> A communicating the inner and outer periphery of the sliding guide tube 13 with the inner peripheral grooves 52 at both ends. The inner tube scraped off by the seal member 60 is formed on the outer periphery of the sliding guide tube 13 and the plurality of circulation grooves 53B are formed in the axial direction to communicate the plurality of circulation holes 53A with the annular outer periphery groove 54 ". The outer circumferential grease 12 is formed in the inner circumferential grooves 52 at both ends, passes through the plurality of circulation holes 53A, and further circulates through the plurality of circulation grooves 53B to the annular outer circumferential groove 54 where the grease reservoir hole 51 is opened. .

  As a result, the total cross-sectional area of the circulation path 53 is increased, and the grease can be smoothly circulated.

  d. By making the seal member 60 an O-ring, the seal member 60 can be made inexpensive.

  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 a front view of the shock absorber partially cut away. FIG. 2 is a cross-sectional view showing the suspension spring support structure of FIG. FIG. 3 is a cross-sectional view showing the lower spring support. FIG. 4 is a cross-sectional view showing the periphery of the upper spring bearing. 5A and 5B show a lower spring receiver, where FIG. 5A is a sectional view and FIG. 5B is a side view. 6A and 6B show an upper spring support, FIG. 6A is a sectional view, FIG. 6B is a plan view, and FIG. 6C is a side view. FIG. 7 is a sectional view showing the periphery of the sliding guide cylinder of FIG. FIG. 8 is a perspective view showing a sliding guide tube. 9A and 9B show a sliding guide tube, where FIG. 9A is a front view, FIG. 9B is a cross-sectional view taken along line BB, and FIG. 9C is a cross-sectional view taken along line CC.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Shock absorber 11 Outer tube 12 Inner tube 12A Drain hole 13 Sliding guide cylinder 14 Piston 15A, 15B Air chamber 21, 22 Spring receiver 23 Suspension spring 26 Collar 27 Bump rubber 28 Cap 31 Air vent passage 31A Hollow part 31B Communication part 41 Air vent passage

Claims (5)

An inner tube is inserted into the outer tube through a sliding guide tube provided at the opening of the outer tube,
A piston that slides in the outer tube is provided on the outer periphery of the upper end of the inner tube, and the piston separates two air chambers above and below the piston,
A cylindrical spring receiver is provided on each of the upper end portion of the inner tube and the upper portion of the outer tube,
In the shock absorber for a vehicle in which the upper and lower ends of the suspension spring are wound around the outer periphery of the cylindrical spring receiver,
An air vent passage is formed in a spring receiver at an upper end portion of the inner tube, and the upper air chamber of the piston is communicated with the outside through the air vent passage and the inner tube. Shock absorber.   2. A hollow portion is formed in a spring receiver at an upper end portion of the inner tube, a communication portion that communicates the inner and outer circumferences is formed at the upper end portion, and the air vent passage is formed by the hollow portion and the communication portion. The shock absorber for vehicles described in 1.   The shock absorber for a vehicle according to claim 1 or 2, wherein the upper air chamber of the piston communicates with the outside through a drain hole provided in a lower portion of the inner tube.   A bump rubber is provided on a spring receiver at an upper end portion of the inner tube via a synthetic resin collar, and the bump rubber is brought into contact with an end face of a spring receiver provided on an upper portion of the outer tube. 4. The vehicle shock absorber according to any one of 3 above.   An air vent passage is formed between a spring receiver on the outer tube side and a cap provided at the upper end of the outer tube, and the upper air chamber of the piston is communicated to the outside through the air vent passage. The vehicle shock absorber according to any one of claims 1 to 4.

Images