JP2012141004A - Hydraulic shock absorber for saddle-type vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydraulic shock absorber for a saddle-type vehicle which forms a dust cover using a simple resin forming die (die).SOLUTION: A plurality of concave paths 92 extending along to a piston rod 61 are formed on a radial inner surface 91 of the dust cover 80, and a plurality of convex guide parts 86 are formed along to the concave paths 92 on a radial outer circumferential surface 85 of the dust cover 80 corresponding to the concave paths 92. A part with the outside formed to be convex is effectively used as a spring guide corresponding to the concave path which circulates air, so that the shape of the dust cover is simplified and the dust cover is formed using the simple die (resin forming die).

Description

  The present invention relates to a straddle-type vehicle hydraulic shock absorber provided with a dust cover.

  The straddle-type vehicle hydraulic shock absorber mainly includes a damper cylinder, a piston rod accommodated in the cylinder, and a spring. And what is equipped with the dust cover is known so that dust etc. may not enter between a cylinder and a piston rod (for example, refer to patent documents 1 (Drawing 6, Drawing 7)).

  A straddle-type vehicle hydraulic shock absorber (10) shown in FIG. 6 of Patent Document 1 (numbers in parentheses indicate reference numerals described in Patent Document 1. The same applies hereinafter) is a so-called inverted-type straddle type. A vehicular hydraulic shock absorber (10) comprising a cylinder (11), a piston rod (12) that slides inside the cylinder (11), and a spring guide member (40) that surrounds the cylinder (11). The dust cover (50) including the main is mainly used.

  As shown in FIG. 7C of Patent Document 1, the dust cover (50) projects four guide portions (42) outward from the outer surface of the cylindrical portion, and these guide portions (42). The spring is guided, 8 protrusions protrude inward from the inner surface of the cylindrical portion, and the vertical groove air passages (44) are formed between adjacent protrusions, for a total of 8 vertical groove air passages (44). This is a molded product that allows air to pass in the front and back direction of the drawing.

A longitudinal groove-like air passage (44) is formed inside from the cylindrical portion and a guide portion (42) is formed outside, but the resin mold tends to be complicated. In particular, as shown in FIG. 7 (c), the cylindrical portion and the guide portion (42) are significantly different in thickness, so that they are drawn to the boundary portion between the guide portion (42) and the cylindrical portion during resin molding. It is easy to come out. Similarly, the boundary portion between the longitudinal groove air passage (44) and the cylindrical portion is likely to be closed.
It is necessary to devise a resin mold so as not to be closed, and the resin mold becomes complicated.
While a reduction in manufacturing cost is required, a dust cover structure that can be manufactured with a simple resin mold is required.

Japanese Patent No. 399937

  An object of the present invention is to provide a straddle-type vehicle hydraulic shock absorber capable of forming a dust cover with a simple resin mold (mold).

  According to a first aspect of the present invention, there is provided a suspension member that is swingably supported by the vehicle body frame, a cylinder that is swingably attached to the suspension member, and a cylinder that slides in the cylinder. A piston rod having one end swingably attached to the body frame, a spring mounted between the rod spring receiving portion on the piston rod side and the cylinder spring receiving portion on the cylinder side, and one end between the cylinder A straddle-type vehicle hydraulic shock absorber having a dust cover extending from the rod spring receiving portion along the piston rod so as to cover the outer periphery of the piston rod so as to cover the outer periphery of the piston rod. A concave recess formed on the side surface and extending along the piston rod, and formed on the outer circumferential surface of the dust cover corresponding to the recess A convex guide portion extending along the concave path, a flange portion integrally formed with the dust cover and extending radially outward between the rod spring receiving portion and the spring, and an upper surface of the flange portion And a communication passage that is formed in communication with the recess and allows air to pass to the outside.

  The invention according to claim 2 is characterized in that the width of the concave path is larger than the depth of the concave path.

  The invention according to claim 3 is characterized in that the recess is formed so as to extend from the opening of the dust cover forming the gap toward one end of the piston rod.

In the invention according to claim 1, the straddle-type vehicle hydraulic shock absorber includes a dust cover, and the dust cover is formed on a radially inner side surface of the dust cover and extends along the piston rod; Corresponding to this concave path, it is provided with a convex guide portion that is formed on the radially outer peripheral surface of the dust cover and extends along the concave path. When the cylinder enters the dust cover, the air in the dust cover is discharged out of the dust cover through the concave path, and the cylinder moves smoothly.
In the present invention, the outer peripheral surface of the concave path is a convex guide part, and the spring is guided by this guide part. By forming the circumferential portion of the dust cover into a bent shape, a concave path can be formed in the circumferential portion. That is, it is not necessary to change the thickness of the dust cover in forming the concave path and the convex guide portion.
If the thickness is uniform, resin molding defects are less likely to occur, and the resin molding die can be simplified.
And since a concave path and a convex path are integrally molded by the relationship of front and back, a structure becomes simple and the cost of a mold can also be reduced.
Furthermore, since the dust cover and the spring guide are integrally formed, the number of parts can be reduced.

  In the invention according to claim 2, the width of the concave path is larger than the depth of the concave path. Since the passage area necessary for flowing air is ensured in the width direction of the concave path without increasing the radial direction of the dust cover, it is possible to reduce the size of the dust cover in the radial direction.

In the invention which concerns on Claim 3, the concave path is formed so that it may extend toward the end of a piston rod from the opening of the dust cover which forms a clearance gap. The concave path extends over the entire length from the opening of the dust cover to the base end portion of the piston rod, and the cross-sectional area (air channel area) of the concave path does not change. Since the flow path area is constant, the air flow can be improved.
In addition, since the concave concave path and the convex guide part serve as ribs, the rigidity of the entire dust cover can be improved.
Furthermore, since a concave path is formed over the entire length of the dust cover, a slide mold is not required in injection molding, and a simpler mold can be formed.

1 is a left side view of a saddle riding type vehicle according to the present invention. 1 is a front view of a straddle-type vehicle hydraulic shock absorber according to the present invention. FIG. 3 is a sectional view taken along line 3-3 in FIG. 2. It is a figure explaining the principal part of the straddle-type vehicle hydraulic shock absorber. FIG. 5 is a sectional view taken along line 5-5 of FIG. It is a perspective view of the dust cover concerning the present invention. It is a figure explaining a resin mold. FIG. 6 is an operation diagram of a straddle-type vehicle hydraulic shock absorber. It is a figure explaining the structural feature of a dust cover.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. Note that the drawings are viewed in the direction of the reference numerals, and the arrow (FRONT) in the drawing represents the front of the vehicle.

Embodiments of the present invention will be described with reference to the drawings.
As shown in FIG. 1, a saddle riding type vehicle 10 includes a handle 12 that is steerably attached to a head pipe 11, and a bottom bridge 14 that is attached to a lower end of the head pipe 11 and supports upper ends of a pair of left and right front forks 13. And a headlamp 15 which is disposed above the head pipe 11 and lights toward the front of the vehicle, and a front wheel 17 which is supported by the front fork 13 and whose upper portion is covered by the front fender 16.

Further, in the vehicle body frame 20, a main frame 21 extends obliquely rearward and downward from the head pipe 11, and a seat rail 22 extends obliquely upward from a middle portion of the main frame 21 to the rear of the vehicle.
The vehicle body frame 20 is composed of the head pipe 11, the main frame 21, the seat rail 22, and the like.

  An engine hanger 23 is fixed to an intermediate portion of the main frame 21, and a pivot plate 24 is fixed to the rear portion of the main frame 21. A power unit 27 including an engine 25 and a transmission 26 is attached to the engine hanger 23 and the pivot plate 24.

A pivot plate 24 is provided with a front end portion of a suspension member 31 so as to be swingable up and down, and a rear wheel 32 is rotatably provided at a rear end portion of the suspension member 31. A chain 35 is stretched over a drive sprocket 33 of the transmission 26 and a driven sprocket 34 attached to the rear wheel 32, and the output of the engine 25 is transmitted to the rear wheel via the chain 35.
Further, a straddle-type vehicle hydraulic shock absorber 50 that absorbs an impact on the rear wheel 32 is provided between the rear portion of the suspension member 31 and the seat rail 22.

A fuel tank 36 is provided on the seat rail 22 above the rear wheel 32, and a storage box 37 is provided on the seat rail 22 in front of the fuel tank 36. The upper side of the storage box 37 and the fuel tank 36 is for riding. It is covered with a sheet 38 so as to be opened and closed.
A vehicle body cover 40 that covers the vehicle body frame 20, the engine 25, the fuel tank 36, and the storage box 37 is attached to the vehicle body frame 20.

  The vehicle body cover 40 includes a front side cover 41 that covers the vehicle width direction of the main frame 21, a leg shield 42 that covers the driver's legs and is disposed in front of the front side cover 41, and the front of the head pipe 11. A front top cover 43 for covering, a main frame top cover 44 covering the rear of the head pipe 11 and covering the upper part of the main frame, an under cover 45 connected to the lower part of the front side cover 41, a fuel tank 36 and a storage box 37 The rear side cover 46 covers the width direction.

  Further, a brake lamp 47 is provided at the rear end portion of the rear side cover 46, and a rear fender 48 that covers the rear wheel 32 is provided on the rear side cover 46 below the brake lamp 47.

Next, the structure of the straddle-type vehicle hydraulic shock absorber 50 will be described.
As shown in FIG. 2, the straddle-type vehicle hydraulic shock absorber 50 is a so-called upright type straddle-type vehicle hydraulic shock absorber 50, and includes a cylinder 51 and a piston that slides in the cylinder 51. A rod (detailed later), a spring 53 mounted between the rod spring receiving portion 62 on the piston rod side and the cylinder spring receiving portion 52 on the cylinder 51 side, and a dust cover extending from the rod spring receiving portion 62 along the axis of the cylinder 51 80 (details will be described later).

  A suspension side attachment member 54 is swingably attached to a suspension member (FIG. 1, reference numeral 31), a cylinder 51 is provided on the suspension side attachment member 54, and a cylinder spring receiving portion 52 is provided below the cylinder 51. Yes. A vehicle body side mounting member 63 is swingably attached to the vehicle body frame (FIG. 1, reference numeral 20), and a rod spring receiving portion 62 is provided on the vehicle body side mounting member 63.

Next, the straddle-type vehicle hydraulic shock absorber 50 will be described with reference to cross-sectional views.
As shown in FIG. 3, in the cylinder 51, an outer cylinder 55 and an inner cylinder 56 are provided concentrically on the suspension-side mounting member 54, and a rod guide 57 that guides the piston rod 61 is provided on the upper end of the inner cylinder 56. An oil seal 58 is provided on the inside of the outer cylinder 55 above the rod guide 57 so as to prevent oil from leaking due to sliding of the piston rod 61. An end plate 59 is provided at the upper end of the outer cylinder 55 above.

  Also, one end of the piston rod 61 is attached to the lower part of the vehicle body side attachment member 63, and the other end of the piston rod 61 enters and slides into the cylinder 51. A piston 64 is provided at the other end of the piston rod 61, and a seal member 65 that seals between the piston 64 and the inner cylinder 56 is provided on the outer periphery of the piston 64.

  Below the piston 64, a lower oil chamber 67 surrounded by the piston 64, the inner cylinder 56, and the bottom 66 is provided. An upper oil chamber 68 surrounded by the piston 64, the inner cylinder 56 and the rod guide 57 is provided above the piston 64. The piston 64 is provided with through holes 71, 71 through which the oil in the lower oil chamber 67 and the upper oil chamber 68 flows, and valves 72, 72 that generate a damping force when the piston rod 61 extends and contracts in the through holes 71, 71. Is provided.

  The valve 72 is urged in a direction to close the through hole 71 by a valve spring supported by a valve stopper 73. When the saddle type vehicle hydraulic shock absorber 50 is contracted, the valve 72 is pushed open to generate a damping force. In the case of extension, a damping force is generated by the flow resistance of a small hole provided in the valve 72.

  A rebound spring 74 is provided between the rod guide 57 and the valve stopper 73 to restrict the stroke when the piston rod 61 extends most. A stopper rubber 75 is provided at the base end portion of the piston rod 61 to restrict the stroke when the piston rod 61 is contracted most.

Next, the dust cover 80 will be described.
As shown in FIG. 4, the dust cover 80 has a cover inner space 81 that is surrounded by the dust cover 80, the vehicle body side mounting member 63, and the cylinder 51 and in which air enters.
In addition, flange portions 82 and 82 extending radially outward are formed integrally with the dust cover 80 between the rod spring receiving portion 62 and the spring 53.

Communication passages 84 and 84 are formed on the upper surfaces 83 and 83 of the flange portions 82 and 82 to allow the air in the cover inner space 81 to pass to the outside. Guide portions 86 for guiding the spring 53 are formed on the radially outer peripheral surfaces 85 and 85 of the dust cover 80.
The cylinder 51 is inserted into the opening 87 at the lower end of the dust cover 80. There are slight gaps 88, 88 between the dust cover 80 and the cylinder 51.

Next, the dust cover 80 will be described based on a cross-sectional view.
As shown in FIG. 5, a dust cover 80 is provided so as to cover the outer periphery of the cylinder 51 and the piston rod 61. A gap 88 is formed between the entire circumference of the cylinder 51 and the dust cover 80.

A plurality of concave recesses 92 extending along the piston rod 61 are formed on the radially inner side surface 91 of the dust cover 80, and the recesses 92 are formed on the radially outer peripheral surface 85 of the dust cover 80 corresponding to the recesses 92. A plurality of convex guide portions 86 are formed along the same.
The width W of the concave path 92 is larger than the depth L of the concave path 92.

  Returning to FIG. 4, the concave path 92 extends along the piston rod 61, and is formed in communication with the communication path 84 on the upper surface 83 of the flange portion 82. The concave path 92 is formed so as to extend from the opening 87 of the dust cover 80 that forms the gap 88 toward one end of the piston rod 61.

Next, the dust cover 80 will be described based on a perspective view.
As shown in FIG. 6, the dust cover 80 has four concave paths 92 at equal intervals in the circumferential direction on the radially inner side surface 91. The concave path 92 is linearly formed in the vertical direction of the figure. Further, a communication path 84 is extended radially outwardly in communication with these concave paths 92.

  A standing wall portion 94 is formed between the bottom surface 93 of the communication path 84 and the top surface 83 of the flange portion 82. A standing wall portion 94 is also formed between the bottom surface 95 of the concave path 94 and the radially inner side surface 91. That is, the standing wall portion 94 of the communication path 84 and the standing wall portion 94 of the recessed path 94 are on the same plane.

  A slight taper may be formed on the radially inner side surface 91 and the bottom surface 95 of the concave path 92. Thereby, when the material of the dust cover 80 is made of resin, it is possible to easily remove the mold from the mold during injection molding.

Next, the metal mold | die of the dust cover 50 is demonstrated.
As shown in FIG. 7, a mold 100 as a resin molding die for a dust cover includes a lower mold 101 and an upper mold 102. The lower mold 101 has a fixed-side mold plate 103, a cavity-side surface 104 formed in a concave shape on the fixed-side template 103, and a positioning recess 105 formed on the bottom of the cavity-side surface 104.

  The cavity-side surface 104 has a shape corresponding to the radially outer peripheral surface (FIG. 6, reference numeral 85) of the dust cover (FIG. 6, reference numeral 80). Of the surface 104 on the cavity side, the surface 106 corresponding to the guide portion (FIG. 6, reference numeral 86) extends linearly in the vertical direction of the drawing, and can be easily removed from the mold.

  The upper side 102 has a movable side mold plate 107, a core side surface 108 formed in a convex shape on the movable side mold plate 107, and a positioning convex portion 111 formed at the tip of the core side surface 108. . Since the positioning convex portion 111 fits into the positioning concave portion 105 when the mold is clamped, the core-side surface 108 of the upper mold 102 can be reliably fixed at the time of injection molding.

  The core-side surface 108 has a shape corresponding to the radially inner side surface (FIG. 6, reference numeral 91) of the dust cover 80. Of the surface 108 on the core side, the surface 112 corresponding to the concave path (FIG. 6, reference numeral 92) extends linearly in the vertical direction of the drawing, and can be easily punched. Note that the surface 106 corresponding to the guide portion and the surface 112 corresponding to the concave path have draft angles.

The operation of the straddle-type vehicle hydraulic shock absorber 50 described above will be described next.
As shown in FIG. 8A, when an impact is applied to the straddle-type vehicle hydraulic shock absorber 50, the cylinder 51 rises as shown by the arrow (1), so that the volume of the cover inner space 81 is increased. Get smaller.

  Then, as shown in (b), the air in the cover inner space 81 is discharged to the outside from the concave path 92 and the communication path 84 as indicated by an arrow (2). Furthermore, the air in the cover inner space 81 is also discharged to the outside through the gap 88 as indicated by an arrow (3). Thereby, the straddle-type vehicle hydraulic shock absorber 50 can appropriately expand and contract without receiving resistance due to the compression of the air in the cover inner space 81.

Next, the effect of the dust cover 80 will be described.
FIG. 9A is a cross-sectional view of a dust cover of a comparative example. In the hydraulic shock absorber 200, a dust cover 202 is disposed outside the cylinder 201, and a spring 203 is disposed outside the dust cover 202.

  The dust cover 202 includes an arc-shaped cylindrical portion 204 serving as a base, an inner convex portion 205 that is formed inside the cylindrical portion 204 and faces the cylinder 201, and a guide portion 206 that is formed outside the cylindrical portion 204 and guides the spring 203. And an air passage 208 which is surrounded by the inner convex portions 205 and 205 adjacent to the inner surface 207 of the cylindrical portion 204 and allows air to pass therethrough.

The outer diameter of the cylinder 201 is d1, the distance from the outer surface of the cylinder 201 to the inner diameter of the spring 203 is W1, and the outer diameter of the spring 203 is D1.
Since the dust cover 202 includes the inner convex portion 205 protruding in the inner peripheral direction and the guide portion 206 protruding in the outer peripheral direction, W1 is increased. As a result, it is necessary to decrease the outer diameter d1 of the cylinder 201 or increase the outer diameter of the spring 203.

  Further, the base end portions of the inner convex portion 205 and the guide portion 206 in the cylindrical portion 204 are thick. For this reason, sink marks tend to occur during injection molding. In order to improve the accuracy of the product, it is necessary to adjust the mold, which increases the cost of adjustment.

  FIG. 9B is a cross-sectional view of the dust cover 80 according to the embodiment. In the saddle type vehicle hydraulic shock absorber 50, the dust cover 80 is disposed outside the cylinder 51, and the spring 53 is disposed outside the dust cover 80. Is arranged.

The outer diameter of the cylinder 51 is d2, the distance from the outer surface of the cylinder 51 to the inner diameter of the spring 53 is W2, and the outer diameter of the spring 53 is D2.
Since the dust cover 80 has the guide portion 86 at a position corresponding to the concave path 92, W2 can be reduced. As a result, the outer diameter d2 of the cylinder 51 can be increased and the capacity of the cylinder 51 can be improved. Alternatively, the outer diameter D2 of the spring 53 can be reduced, and the saddle type vehicle hydraulic shock absorber 50 can be downsized in the radial direction.

  Furthermore, since the thickness of the guide cover 80 is substantially uniform, sink marks are less likely to occur during injection molding. As a result, the mold can be easily adjusted, and the adjustment cost can be reduced.

The effects of the saddle riding type vehicle hydraulic shock absorber 50 described above will be described below.
As shown in FIG. 4, the straddle-type vehicle hydraulic shock absorber 50 includes a dust cover 80, and the dust cover 80 is formed on the radially inner side surface of the dust cover 80 and extends along the piston rod 61. Corresponding to the concave path 92, and a convex guide portion 86 formed on the radial outer peripheral surface 85 of the dust cover 80 and extending along the concave path 92. When the cylinder 51 enters the dust cover 80, the air in the dust cover 80 is discharged out of the dust cover 80 through the concave path 92, and the smooth movement of the cylinder 51 is maintained.

In the present invention, the outer peripheral surface of the concave path 92 is a convex guide portion 86, and the spring 53 is guided by the guide portion 86. By forming the circumferential portion of the dust cover 80 into a bent shape, the concave path 92 can be formed in the circumferential portion. That is, it is not necessary to change the thickness of the dust cover 80 in forming the concave path 92 and the convex guide portion 86.
If the wall thickness is uniform, resin molding defects are unlikely to occur, and the resin molding die 100 shown in FIG. 7 can be simplified.
And since the concave path 92 and the convex path are integrally formed with the front and back relationship, the structure becomes simple and the cost of the mold can be reduced.
Furthermore, since the dust cover 80 and the guide part 86 are integrally formed, the number of parts can be reduced.

  As shown in FIG. 5, the width W of the concave path 92 is larger than the depth L of the concave path 92. Since the passage area necessary for flowing air is secured in the width direction of the concave path 92 without increasing the radial direction of the dust cover 80, the dust cover 80 can be reduced in size in the radial direction.

  As shown in FIG. 4, the concave path 92 is formed so as to extend from the opening 87 of the dust cover 80 that forms the gap 88 toward one end of the piston rod 61. The concave path 92 extends over the entire length from the opening 87 of the dust cover 80 to the proximal end portion of the piston rod 61, and the cross-sectional area (air channel area) of the concave path 92 does not change. Since the flow path area is constant, the air flow can be improved.

In addition, since the concave recess 92 and the convex guide portion 86 serve as ribs, the rigidity of the entire dust cover 80 can be improved.
Further, since the concave path 92 is formed over the entire length of the dust cover 80, a slide mold is not required in the injection molding, and a simpler mold 100 can be formed as shown in FIG.

  In the embodiment, the saddle type vehicle hydraulic shock absorber 50 according to the present invention has four recesses 92 of the dust cover 80, but the present invention is not limited to this. It can be changed.

  The straddle-type vehicle hydraulic shock absorber according to the present invention is suitable for a straddle-type vehicle.

  DESCRIPTION OF SYMBOLS 10 ... Saddle type vehicle, 20 ... Body frame, 31 ... Suspension member, 50 ... Saddle type vehicle hydraulic shock absorber, 51 ... Cylinder, 52 ... Cylinder spring receiving part, 53 ... Open spring, 61 ... Piston rod, 62 ... Rod spring receiving portion, 80 ... dust cover, 82 ... flange portion, 83 ... upper surface, 84 ... communication path, 85 ... radial outer peripheral surface, 86 ... guide portion, 87 ... opening, 88 ... gap, 91 ... radial inner side surface, 92: concave path, W: width of the concave path, L: depth of the concave path.

Claims (3)

A suspension member (31) swingably supported by the vehicle body frame (20), a cylinder (51) having one end swingably attached to the suspension member (31), and the inside of the cylinder (51) A piston rod (61) having one end swingably attached to the body frame (20) so as to slide, a rod spring receiving portion (62) on the piston rod (61) side, and the cylinder (51) A gap (88) is formed between the spring (53) mounted between the cylinder spring receiving part (52) on the side and the cylinder (51) at one end so as to cover the outer periphery of the piston rod (61). A straddle-type vehicle hydraulic shock absorber (50) comprising a dust cover (80) extending from the rod spring receiving portion (62) along the piston rod (61);
A concave recess (92) formed on the radially inner side surface (91) of the dust cover (80) and extending along the piston rod (61);
A convex guide part (86) formed on the radial outer peripheral surface (85) of the dust cover (80) corresponding to the concave path (92) and extending along the concave path (92);
A flange portion (82) formed integrally with the dust cover (80) and extending radially outward between the rod spring receiving portion (62) and the spring (53);
A straddle-type vehicle hydraulic system comprising a communication passage (84) formed on the upper surface (83) of the flange portion (82) so as to communicate with the concave passage (92) and allow air to flow to the outside. Shock absorber.   The straddle-type vehicle hydraulic shock absorber according to claim 1, wherein a width (W) of the concave path is larger than a depth (L) of the concave path.   The concave path (92) is formed to extend from an opening (87) of the dust cover (80) forming the gap (88) toward one end of the piston rod (61). The straddle-type vehicle hydraulic shock absorber according to claim 1 or 2.

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