JP2011202702A - Front fork - Google Patents

Abstract

PROBLEM TO BE SOLVED: To compensate for the shortage of a reaction force of a damper leg relative to a spring leg while attaining the weight saving of a front fork and reduction in cost.SOLUTION: The front fork A includes a pressure side throttle member 60 on the outer periphery of a damper cylinder 21 in the damper leg 10. The pressure side throttle member 60 includes an annular part attached to the outer periphery of the damper cylinder 21, and a plurality of ribs 62 respectively arranged at a plurality of positions in the circumferential direction of the outer surface of the annular part and extending in the axial direction of the annular part. A groove-like throttle flow passage 63 is formed between the ribs adjacent to each other. The shortage of the reaction force relative to the spring reaction force of the spring leg 110 is compensated by a pressure side damping force that occurs in a damper 20 of the damper leg 10 by a pressure side damping force resulting from flow passage resistance exerted to an operating oil of an oil reservoir chamber 24 by the throttle flow passage 63 of the pressure side throttle member 60 in the damper leg 10 during a high piston speed and a large stroke in a pressure side stroke.

Description

  The present invention relates to a front fork suitable for use in a motorcycle or the like.

  Conventionally, in order to reduce the weight and cost of a front fork, there is a front fork in which a damper leg with a built-in damper and a spring leg with a built-in suspension spring are arranged in parallel. In this front fork, the suspension spring of the spring leg generates a large spring reaction force during a large stroke in the compression stroke, whereas the damping force generated by the damper leg damping force generator depends on the piston speed. Depends on stroke, does not get higher. For this reason, during a large stroke in the compression side stroke, the reaction force caused by the damping force of the damper leg becomes unbalanced with respect to the large spring reaction force of the spring leg, and as a result, the handle is shaken when a disturbance is input ( (Yaw direction) tends to be promoted.

  Therefore, in the front fork described in Patent Document 1, an elastic body made of rubber, urethane foam or the like is provided on the damper leg. The elastic body is interposed between an upper end cap of the vehicle body side tube and an upper portion of a damper cylinder provided upright on the axle side tube. Due to this, due to the spring reaction force generated by the elastic body built in the damper leg during a large stroke of the compression side stroke, the compression side damping force generated by the damper leg damper is insufficient for the reaction force against the large spring reaction force of the spring leg. Make up.

JP-A-8-74910

  The front fork described in Patent Document 1 includes an elastic body made of rubber, foamed urethane, or the like in the damper leg in order to compensate for a lack of reaction force of the damper leg against the spring leg. The elastic body built in the damper leg generates a constant spring reaction force at the time of a large stroke, requires a constant cross section and length, and goes against the weight reduction and cost reduction of the front fork.

  An object of the present invention is to compensate for a lack of reaction force of a damper leg against a spring leg while reducing the weight and cost of a front fork.

  According to the first aspect of the present invention, a damper leg with a built-in damper and a spring leg with a built-in suspension spring are arranged in parallel, and the damper leg is attached to the outer tube attached to one of the vehicle body side and the axle side. Insert the inner tube attached to the other side of the axle side, place the damper inside the outer tube and the inner tube, suspend the damper cylinder of the damper on the center of the outer tube or inner tube attached to the vehicle body side, The piston rod of the piston rod standing in the center of the inner tube or outer tube attached to the side is inserted into the damper cylinder, and the outside of the damper serves as an oil reservoir chamber. A compression side throttle member is provided, and the compression side throttle member includes an annular portion attached to the outer periphery of the damper cylinder, and a ring. A plurality of ribs provided in each of a plurality of positions along the circumferential direction of the outer surface of the part and extending in the axial direction of the annular part, and forming a groove-shaped throttle channel between adjacent ribs, Generated by the damper leg damper due to the compression side damping force generated by the flow path resistance exerted on the hydraulic oil in the oil reservoir chamber by the throttle flow path of the compression side throttle member at the damper leg at a high piston speed and a large stroke in the compression stroke. The compression side damping force compensates for the lack of reaction force against the spring reaction force of the spring leg.

  According to a second aspect of the present invention, in the first aspect of the invention, the rib forming the throttle flow path of the compression side throttle member is an inclined rib that extends while being inclined in a direction along the axial direction of the annular portion. It is what I did.

  According to a third aspect of the present invention, in the second aspect of the present invention, the annular portion of the compression side throttle member is rotatably attached to the outer periphery of the damper cylinder.

  The invention according to claim 4 is the invention according to claim 2 or 3, further comprising two groove wall surfaces on both sides forming respective grooved throttle channels adjacent to the inclined ribs of the compression side throttle member. The angle formed by one groove wall surface facing the pressurized side of the oil reservoir chamber with respect to the circumferential direction of the annular portion is made smaller than the angle formed by the other groove wall surface with respect to the circumferential direction of the annular portion. It was made to become.

  The invention according to claim 5 is the invention according to any one of claims 2 to 4, wherein the restriction of one inclined rib is further between the inclined ribs adjacent to each other across the restriction flow path of the compression side restricting member. The groove wall surface that forms the flow path and the groove wall surface that forms the throttle flow path of the other inclined rib partially overlap each other when viewed in the axial direction of the annular portion.

(Claim 1)
(a) The compression side throttle member provided on the damper leg, together with the damper cylinder attached to the vehicle body side tube, strokes in the oil reservoir chamber over the oil level in the compression side stroke. At this time, the expansion / contraction reference position (for off-road vehicles, the vehicle is in the aerial position as a reference, i.e., free extension in or near the maximum free extension state where no load on the vehicle body acts on the front fork. In the case of an on-road vehicle, the vehicle body side load at this time is acting on the front fork with reference to when the vehicle receives a load from one occupant. At the time of a small stroke of the compression side stroke from the position where the expansion / contraction length is made), almost no damping force is generated above the oil level of the oil reservoir, and low damping force is generated near the oil level where there is a lot of bubbles mixed . When the pressure side stroke has a high piston speed and a large stroke, a highly stroke-dependent damping force due to the flow path resistance of the pressure side throttle member is generated on the bottom side where the bubbles in the oil reservoir chamber are less mixed. That is, the compression-side throttle member of the damper leg generates a compression-side damping force that depends on the stroke in the compression-side stroke, and generates a stable high damping force during a large stroke.

  In addition, the compression-side throttle member of the damper leg pressurizes the oil chamber below the compression-side throttle member and strokes the pressurized oil in the groove-shaped throttle channel when the oil stroke chamber strokes at a high piston speed during the compression-side stroke. A damping force having a high speed dependency due to the flow path resistance of the throttle and the compression side throttle member is generated. At this time, the pressure-side throttle member rectifies the oil pressurized in the lower oil chamber into a high-speed flow guided by the groove-like throttle flow path, and the circumference of the damper cylinder is directed to the oil chamber above the pressure-side throttle member. Stable flow without turbulent diffusion. Therefore, in the oil reservoir chamber, the oil flow is stabilized in the upper and lower oil chambers sandwiching the pressure side throttle member, and the pressure side throttle member also generates a higher damping force that is more stable at a high piston speed and a large stroke. .

  Therefore, with the front fork in which the damper leg and spring leg are arranged in parallel, the flow path resistance exerted on the hydraulic oil in the oil reservoir chamber by the throttle channel of the compression side throttle member at the damper leg at high piston speed and large stroke in the compression side stroke Due to the high compression side damping force generated due to this, the speed-dependent compression side damping force generated by the damping force generator provided in the damper leg damper compensates for the lack of reaction force against the spring reaction force of the spring leg. During the large stroke of the compression side stroke, the reaction force caused by the damping force of the damper leg and the spring reaction force generated by the spring leg are balanced to suppress the swinging of the handle (yaw direction) during disturbance input. it can.

  (b) The compression-side throttle member of the damper leg has a plurality of ribs provided in each of a plurality of positions along the circumferential direction of the outer surface of the annular portion and extending in the axial direction of the annular portion, and between the adjacent ribs. A grooved throttle channel is formed in When a lateral external force acting on the damper leg (a longitudinal external force along the traveling direction) causes the vehicle body side tube and the axle side tube to undergo lateral bending deformation of their central axes, they are suspended at the center of the vehicle body side tube. The compression side throttle member provided on the outer periphery near the lower end of the damper cylinder may be eccentric as shown in FIG. 7 with respect to the inner periphery of the vehicle body side tube or the axle side tube. At this time, even on the side where the outer periphery of the compression side throttle member provided in the damper cylinder and the inner periphery of the vehicle body side tube or the axle side tube are close to or in contact with each other, the outer periphery of the compression side throttle member is formed on a part of the rib. Although close to or in contact with the inner periphery of the side tube or axle side tube, a grooved throttle channel must be provided between the inner periphery of the vehicle body side tube or axle side tube as shown in FIGS. Secure. Therefore, even if the outer periphery of the pressure side throttle member is close to or in contact with the inner periphery of the vehicle body side tube or the axle side tube, there is no possibility of closing the throttle flow path at that time, and the pressure side throttle member affects the oil in the oil reservoir chamber. There is no possibility of causing a rapid change in the channel resistance. The compression-side throttle member can generate a stable damping force even when a lateral bending deformation occurs in the damper leg.

  Since a compact and lightweight compression side throttle member made of resin or the like is used, it is possible to compensate for a lack of reaction force of the damper leg against the spring leg while reducing the weight and cost of the front fork.

(Claim 2)
(c) The rib that forms the throttle channel of the compression side throttle member is an inclined rib that is inclined and extends in a direction along the axial direction of the annular portion. During the compression stroke, the compression throttle member strokes at a high piston speed, pressurizes the lower oil chamber with the compression throttle member, and guides the pressurized oil through the grooved throttle channel to rectify it into a high-speed flow. The flow is rectified by the inclined rib into a spiral flow inclined with respect to the direction along the axial direction of the annular portion, and the rectifying effect is enhanced.

(Claim 3)
(d) The annular portion of the compression side throttle member of (c) described above is rotatably attached to the outer periphery of the damper cylinder. The rectifying effect of the above (c) by the compression side throttle member is further enhanced.

(Claim 4)
(e) When two groove wall surfaces forming respective grooved throttle channels adjacent to each other are disposed on both sides of the inclined ribs of the compression side throttle member, the pressure side throttle member faces the side pressurized in the pressure side stroke. The angle θa formed by the groove wall surface with respect to the circumferential direction of the annular portion is made smaller than the angle θb formed by the other groove wall surface with respect to the circumferential direction of the annular portion. Thus, the groove wall surface of the inclined rib that collides when the oil in the lower oil chamber pressurized by the pressure side throttle member in the pressure side stroke enters the groove-like throttle channel of the pressure side throttle member has a large resistance to the oil. Accordingly, the damping force generated due to the flow path resistance of the compression side throttle member is further increased. Conversely, in the extension stroke, the oil that enters the groove-shaped throttle channel of the compression-side throttle member from the oil chamber above the compression-side throttle member has a lower resistance received from the groove wall surface of the inclined rib that collides with it, and the pressure-side throttle member It returns to the lower oil chamber smoothly, and is prepared when the pressure side is reversed.

  When the oil flowing from the lower oil chamber to the upper oil chamber in the pressure side throttle member passes through the groove-like throttle channel of the pressure side throttle member, the difference between the angles θa and θb of the two groove wall surfaces, Due to the difference in wall length along the flow direction, the flow of oil flowing in contact with one groove wall surface is slower than the flow of oil flowing in contact with the other groove wall surface. For this reason, the flow on the side of one groove wall surface is drawn into the flow on the side of the other groove wall surface in the groove-shaped throttle channel of the compression side throttle member, and for example, a right-handed screw flow is generated. The right-handed screw flow generated in each of the plurality of groove-shaped throttle channels provided on the outer periphery of the compression-side throttle member flows around the damper cylinder from each of the groove-shaped throttle channels toward the upper oil chamber. become. The oil flowing out from each groove-like throttle channel of the compression side throttle member continues to be more reliably rectified without being disturbed and diffused in all directions around the damper cylinder, thereby further enhancing the rectification effect.

(Claim 5)
(f) Between the inclined ribs adjacent to each other across the throttle channel of the compression side throttle member, the groove wall surface forming the throttle channel of one inclined rib and the throttle channel of the other inclined rib The groove wall surface to be formed partially overlaps the axial direction of the annular portion. When the damper leg undergoes lateral bending deformation, the inclined rib of the compression side throttle member can support the entire circumference of the inner peripheral surface of the vehicle body side tube or the axle side tube without any gap in the circumferential direction. Regardless of the assembly direction of the pressure side throttle member, the annular part of the pressure side throttle member idles on the outer periphery of the damper cylinder, and the mounting angle position with respect to the inner peripheral surface of the vehicle body side tube or axle side tube changes. The entire circumference of the surface can be supported without gaps in the circumferential direction. Therefore, it is possible to easily and reliably improve the rigidity of the damper leg against lateral bending deformation.

FIG. 1 is a schematic cross-sectional view showing a front fork. FIG. 2 is a schematic cross-sectional view showing a damper leg. FIG. 3 is a schematic cross-sectional view showing a spring leg. FIG. 4 is a longitudinal sectional view showing a main part of the damper leg. FIG. 5 is a cross-sectional view showing the main part of the damper leg. 6A and 6B show the compression side throttle member, where FIG. 6A is a side view and FIG. 6B is a plan view. FIG. 7 is a schematic view showing a usage state of the compression side throttle member. FIG. 8 shows a modification of the compression side throttle member, where (A) is a side view and (B) is a plan view. FIG. 9 shows a modification of the compression side throttle member, where (A) is a perspective view, (B) is a longitudinal sectional view, and (C) is a plan view. FIG. 10 shows a modification of the compression side throttle member, where (A) is a perspective view, (B) is a longitudinal sectional view, and (C) is a plan view.

  In the front fork A, a damper leg 10 including a damper 20 and not including a suspension spring made of a metal spring and a spring leg 110 not including a damper and including a suspension spring 150 made of a metal spring are arranged in parallel.

(Damper leg 10) (FIGS. 1, 2, and 4)
As shown in FIGS. 1 and 2, the damper leg 10 is slidably inserted into a vehicle body side tube (outer tube) 11 with an axle side tube (inner tube) 12 sealed through a seal member 13. A single cylinder damper 20 is disposed inside the tube 11 and the axle tube 12. The damper 20 suspends the damper cylinder 21 at the center inside the vehicle body side tube 11, and inserts the piston 23 of the piston rod 22 erected at the center inside the axle side tube 12 into the damper cylinder 21. The outside of the cylinder 21 and the piston rod 22) is an oil reservoir chamber 24. In the oil reservoir chamber 24, the oil chamber 25 and the air chamber 26 are in contact via a free interface.

  The vehicle body side tube 11 is supported on the vehicle body side, and the axle side tube 12 is coupled to the axle. The upper end portion of the damper cylinder 21 is screwed and sealed to the upper end portion of the vehicle body side tube 11, and the upper opening end of the damper cylinder 21 is closed and sealed with a fork bolt 31.

  An axle bracket 32 is screwed and sealed to the lower end portion of the axle-side tube 12, and a lower end portion of the piston rod 22 is erected on the axle bracket 32 inside the axle-side tube 12. An oil lock collar 33 </ b> A is fixed on the bracket 32. The piston rod 22 is slidably supported by a bush 35 and a seal member 36 of a rod guide 34 screwed to a lower opening end of the damper cylinder 21 and is supported in a sealed state, and is inserted into the damper cylinder 21 (FIG. 4). . An oil lock piece 33B is provided on the outer periphery of the rod guide 34.

  The damper 20 includes a main valve device (extension-side damping force generation device) 40 and a sub-valve device (compression-side damping force generation device) 50. The damper 20 dampens the expansion and contraction vibration of the vehicle body side tube 111 and the axle side tube 112 due to the absorption of the impact force by the suspension spring 150 of the spring leg 110 by the damping force generated by the main valve device 40 and the sub valve device 50.

(Main valve device 40)
The main valve device 40 divides the inside of the damper cylinder 21 into a piston-side oil chamber 41A and a rod-side oil chamber 41B by the piston 23 at the upper end of the piston rod 22. The piston 23 includes an expansion-side damping valve 42A and includes an expansion-side flow passage 42 that connects the piston-side oil chamber 41A and the rod-side oil chamber 41B, and a compression-side attenuation valve (check valve) 43A. And a pressure side channel 43 communicating with the rod side oil chamber 41B.

(Sub-valve device 50)
The sub valve device 50 suspends a guide pipe 51 at the center of a fork bolt 31 provided at the upper opening end of the damper cylinder 21, and a sub piston 52 at the lower end of the guide pipe 51 is disposed relative to the piston 23 inside the damper cylinder 21. Then, the sub tank chamber 53 is partitioned and formed above the piston side oil chamber 41A. The sub-piston 52 is provided with a pressure-side damping valve 54A to connect the piston-side oil chamber 41A and the sub-tank chamber 53, and an extension-side damping valve (check valve) 55A to provide the piston-side oil chamber 41A and the sub-tank chamber. And an extension-side flow channel 55 that communicates with 53.

  The sub-valve device 50 is provided with a free piston 56 movably around the guide pipe 51 inside the damper cylinder 21, and a pressurizing spring 57 composed of a compression coil spring interposed between the free piston 56 and the fork bolt 31. Thus, the free piston 56 is urged toward the sub-piston 52 side.

  The sub valve device 50 brings the oil in the oil reservoir chamber 24 adhering to the outer periphery of the piston rod 22 into the damper cylinder 21 from the seal member 36, and increases the hydraulic pressure in the oil chambers 41A and 41B and the sub tank chamber 53. When the free piston 56 moves to the ascending end due to the increased hydraulic pressure, the oil hole 58 provided in the damper cylinder 21 communicates the sub tank chamber 53 with the air chamber 26 of the oil reservoir chamber 24, and the high pressure oil in the sub tank chamber 53 is discharged. Return to the oil reservoir chamber 24 side.

(Spring leg 110) (FIGS. 1 and 3)
As shown in FIGS. 1 and 3, the spring leg 110 is inserted into the vehicle body side tube (outer tube) 111 through the seal member 113 so that the axle side tube (inner tube) 112 is slidable and sealed. The spring leg 110 is configured such that the guide cylinder 121 is erected at the center inside the axle side tube 112 and the tip guide 123 of the guide rod 122 suspended at the center inside the vehicle body side tube 111 is slidable on the guide cylinder 121. Inserting.

  The vehicle body side tube 111 is supported on the vehicle body side, and the axle side tube 112 is coupled to the axle. The upper opening end of the vehicle body side tube 111 is closed and sealed with a fork bolt 131, and a spring adjuster 141 of a spring load adjustment device 140 is pivotally supported in a sealed state so as to be rotatable at the center of the fork bolt 131. A guide rod 122 is connected to the lower end portion and suspended.

  An axle bracket 132 is screwed and sealed to the lower end portion of the axle side tube 112, and the lower end portion of the guide cylinder 121 is erected on the axle bracket 132 inside the axle side tube 112. The guide rod 122 is slidably supported by a bush 134 of a rod guide 133 screwed to the upper opening end of the guide cylinder 121 and is inserted into the guide cylinder 121.

  The spring load adjusting device 140 is provided with a retaining plate 141A and an adjuster bolt 142 in the axial direction of the outer periphery of the spring adjuster 141 inserted into the vehicle body side tube 111, and the adjuster bolt 142 fixed to the spring adjuster 141 is adjusted to the adjuster bolt 142. A nut 143 is screwed.

  The adjuster nut 143 engages the outer peripheral protrusion 143A with the key groove 131A provided in the axial direction of the inner periphery of the fork bolt 131 to prevent the adjuster nut 143 from rotating in the axial direction, and the spacer 144 provided on the lower end surface of the adjuster nut 143. The spring receiver 145 is supported via A suspension spring 150 made of a metal compression coil spring is disposed in a spring accommodating chamber 151 formed by an annular gap between the inner circumference of the vehicle body side tube 111 and the axle side tube 112 and the outer circumference of the guide cylinder 121 and the guide rod 122. The suspension spring 150 is interposed between the spring receiver 145 of the spring load adjusting device 140 and the spring receiver 146 provided on the upper surface of the axle bracket 132. The initial load of the suspension spring 150 can be adjusted by adjusting the position of the adjuster bolt 142 by the spring adjuster 141 of the spring load adjusting device 140.

  The guide cylinder 121 defines an oil chamber 124 at the lower portion of the guide 123 and an air chamber 125 at the upper portion, and communicates the oil chamber 124 and the air chamber 125 with the spring accommodating chamber 151 outside the guide cylinder 121. Holes 124A and 125A are provided. The guide 123 also includes a communication path 127 that allows the oil chamber 124 and the air chamber 125 to communicate with each other. Oil is stored in the oil chamber 124 and the spring housing chamber 151, and the oil is used to seal the seal member 113 of the vehicle body side tube 111 and the axle side tube 112, the bush 134 of the rod guide 133, the suspension spring 150 and the axle side tube 112 or Lubrication of the sliding contact portion with the guide cylinder 121 is performed.

  Accordingly, in the front fork A, the spring is caused by the damping force generated by the extension side damping valve 42A of the extension side damping force generator 40 and the compression side damping valve 54A of the compression side damping force generator 50 in the damper 20 of the damper leg 10. The expansion and contraction vibration of the vehicle body side tube 111 and the axle side tube 112 due to the absorption of the impact force by the suspension spring 150 of the leg 110 is suppressed.

  However, the front fork A has the following configuration in order to compensate for insufficient reaction force of the damper leg 10 against the spring leg 110 while reducing the weight and cost.

  As shown in FIGS. 4 and 5, the damper leg 10 is provided with a compression side throttle member 60 on the outer periphery of the damper cylinder 21. The compression side throttle member 60 is composed of a resin molded body or the like, and is mounted on upper and lower mounting members positioned on the outer periphery on the lower end side of the damper cylinder 21 suspended in the center of the vehicle body side tube 11 by upper and lower retaining rings 71A and 72A. By 71 and 72, it is pinched and supported from both the upper and lower sides in the axial direction. The compression-side throttle member 60 is not restricted in the circumferential mounting position on the outer periphery of the damper cylinder 21 and is freely rotatable on the outer periphery of the damper cylinder 21 (it may be fixed so as not to rotate).

  As shown in FIG. 6, the compression-side throttle member 60 is provided at each of an annular portion 61 attached to the outer periphery of the damper cylinder 21 and a plurality of positions (six positions in the present embodiment) along the circumferential direction of the outer surface of the annular portion 61. A plurality of ribs 62 extending in the axial direction of the annular portion 61, and a groove-shaped throttle channel 63 is formed between the adjacent ribs 62. The annular portion 61 of the compression side throttle member 60 is rotatably attached to the outer periphery of the damper cylinder 21 as described above.

  The front fork A has a flow path resistance that the throttle channel 63 of the compression side throttle member 60 in the damper leg 10 exerts on the hydraulic oil in the oil chamber 25 of the oil reservoir chamber 24 at a high piston speed and a large stroke in the compression side stroke of the damper leg 10. The compression side damping force generated by the damping force generation devices 40 and 50 of the damper 20 of the damper leg 10 (particularly the compression side damping valve 54A of the compression side damping force generation device 50) due to the compression side damping force caused by The shortage of the reaction force against the spring reaction force of the spring 150 is compensated.

That is, the front fork A has the following operational effects.
(a) The compression side throttle member 60 provided on the damper leg 10 strokes in the oil reservoir chamber 24 in the pressure side stroke along with the damper cylinder 21 attached to the vehicle body side tube 11 over the oil level. At this time, the expansion / contraction reference position (for off-road vehicles, the vehicle is in an aerial position as a reference, that is, free extension in the maximum free extension state where the vehicle body side load does not act on the front fork A or in the vicinity thereof. The on-road vehicle has a vehicle-side load acting on the front fork A at the time of stopping the vehicle that received the load of one passenger. In the small stroke of the compression side stroke from the position where the expansion and contraction length of the oil is present), almost no damping force is generated above the oil surface of the oil reservoir chamber 24, and low damping force in the vicinity of the oil surface where many bubbles are mixed. Is generated. At the time of a high piston speed and a large stroke in the compression side stroke, a highly stroke-dependent damping force due to the flow path resistance of the compression side throttle member 60 is generated on the bottom side of the oil reservoir chamber 24 where there is little mixing of bubbles. That is, the compression-side throttle member 60 of the damper leg 10 generates a compression-side damping force depending on the stroke in the compression-side stroke, and generates a stable and high damping force during a large stroke.

  Further, the pressure side throttle member 60 of the damper leg 10 pressurizes the oil chamber 25A below the pressure side throttle member 60 when the stroke in the oil reservoir chamber 24 is performed at a high piston speed in the pressure side stroke, and the pressurized oil is grooved. The diaphragm-shaped restricting channel 63 generates a damping force that is highly dependent on the speed and is caused by the channel resistance of the compression-side restricting member 60. At this time, the pressure-side throttle member 60 rectifies the oil pressurized in the lower oil chamber 25 </ b> A into a high-speed flow guided by the groove-like throttle channel 63, and the damper toward the oil chamber 25 </ b> B above the pressure-side throttle member 60. The periphery of the cylinder 21 is allowed to flow stably without being disturbed in all directions. Therefore, in the oil reservoir chamber 24, the oil flow is stabilized by the upper and lower oil chambers 25A and 25B sandwiching the pressure side throttle member 60, and the pressure side throttle member 60 also has a higher damping force that is more stable at a high piston speed and a large stroke. Will be generated.

  Accordingly, with the front fork A in which the damper leg 10 and the spring leg 110 are arranged in parallel, the throttle channel 63 of the compression side throttle member 60 in the damper leg 10 operates the oil reservoir chamber 24 at a high piston speed and a large stroke in the compression side stroke. Due to the high compression side damping force generated due to the flow path resistance exerted on the oil, the speed-dependent compression side damping force generated by the damping force generators 40 and 50 mounted on the damper 20 of the damper leg 10 is the spring of the spring leg 110. Make up for the lack of reaction force against reaction force. During a large stroke in the compression side stroke, the reaction force caused by the damping force of the damper leg 10 and the spring reaction force generated by the spring leg 110 are balanced, and the handle is shaken when a disturbance is input (yaw direction). Can be suppressed.

  (b) The compression-side throttle member 60 of the damper leg 10 has a plurality of ribs 62 provided at each of a plurality of positions along the circumferential direction of the outer surface of the annular portion 61 and extending in the axial direction of the annular portion 61. A groove-shaped throttle channel 63 is formed between adjacent ribs 62. When the vehicle body side tube 11 and the axle side tube 12 cause lateral bending deformation of their central axes due to a lateral external force acting on the damper leg 10 (front and rear direction external force along the traveling direction), the suspension is suspended at the center of the vehicle body side tube 11. As shown in FIG. 7, the compression side throttle member 60 provided on the outer periphery near the lower end of the lowered damper cylinder 21 may be eccentric with respect to the inner periphery of the vehicle body side tube 11 or the axle side tube 12. . At this time, the outer periphery of the pressure-side throttle member 60 is provided at a part of the pressure-side throttle member 60 on the side where the outer periphery of the compression-side throttle member 60 provided in the damper cylinder 21 and the inner periphery of the vehicle body-side tube 11 or the axle-side tube 12 approach or contact each other. 7A and 7B, the rib 62 is close to or in contact with the inner periphery of the vehicle body side tube 11 or the axle side tube 12 but between the inner periphery of the vehicle body side tube 11 or the axle side tube 12. As shown in FIG. 4, a groove-like throttle channel 63 is secured. Therefore, even if the outer circumference of the pressure side throttle member 60 is close to or in contact with the inner circumference of the vehicle body side tube 11 or the axle side tube 12, there is no possibility of closing the throttle flow path 63 in that range, and the pressure side throttle member 60 is not filled with oil. There is no possibility of causing a rapid change in the flow resistance exerted on the oil in the chamber 24. The compression-side throttle member 60 can generate a stable damping force even when the damper leg 10 undergoes lateral bending deformation.

  FIG. 7C shows a compression side throttle member 60 that does not have a rib, and closes the throttle flow path in a range close to or in contact with the inner periphery of the vehicle body side tube 11 or the axle side tube 12.

  Since the small and lightweight compression side throttle member 60 made of resin or the like is used, it is possible to compensate for the insufficient reaction force of the damper leg 10 against the spring leg 110 while reducing the weight and cost of the front fork A.

  A compression-side throttle member 60A shown in FIG. 8 is a modification of the compression-side throttle member 60, and the rib 62 that forms the throttle channel 63 is tapered, and the channel of the throttle channel 63 between adjacent ribs 62 is shown. The resistance is gradually reduced from the side facing the lower oil chamber 25A pressurized in the pressure side stroke of the oil reservoir chamber 24 toward the upper oil chamber 25B. In the pressure side stroke of the damper leg 10, a higher damping force can be generated by the pressure side throttle member 60A.

  9 is a modification of the pressure side throttle member 60, and is provided at each of an annular portion 81 attached to the outer periphery of the damper cylinder 21 and a plurality of positions along the circumferential direction of the outer surface of the annular portion 81. And a plurality of ribs 82 extending in the axial direction of the annular portion 81, and a groove-shaped throttle channel 83 is formed between adjacent ribs 82. At this time, the rib 82 forming the throttle channel 83 is an inclined rib 82 that is inclined and extended in a direction along the axial direction of the annular portion 81. In the pressure side stroke, the pressure side throttle member 80 strokes at a high piston speed, the pressure side throttle member 80 pressurizes the lower oil chamber 25A, and the pressurized oil is guided by the grooved throttle channel 83 to rectify into a high-speed flow. At this time, the high-speed flow is rectified by the inclined rib 82 into a spiral flow that is inclined with respect to the direction along the axial direction of the annular portion 81, and the rectifying effect is enhanced.

  When the annular portion 81 of the pressure side throttle member 80 is rotatably attached to the outer periphery of the damper cylinder 21, the above-described rectifying effect by the pressure side throttle member 80 is further enhanced.

  Further, in the pressure side throttle member 80 (or a pressure side throttle member 80A described later), the throttle channel 83 of one of the inclined ribs 82 is disposed between the adjacent inclined ribs 82 with the throttle channel 83 interposed therebetween. And the groove wall surface 82B forming the throttle channel 83 of the other inclined rib 82 partially overlap each other when viewed in the axial direction of the annular portion 81. When the damper leg 10 undergoes lateral bending deformation, the inclined rib 82 of the compression side throttle member 80 can support the entire circumference of the inner peripheral surface of the vehicle body side tube 11 or the axle side tube 12 without any gap in the circumferential direction. The annular portion 81 of the compression side throttle member 80 idles on the outer periphery of the damper cylinder 21, and the mounting angle position with respect to the inner peripheral surface of the vehicle body side tube 11 or the axle side tube 12 changes. In addition, the entire circumference of those inner peripheral surfaces can be supported without gaps in the circumferential direction. Therefore, the rigidity with respect to the lateral bending deformation of the damper leg 10 can be improved easily and reliably.

  A compression side throttle member 80A shown in FIG. 10 is a modification of the compression side throttle member 80, and has two groove wall surfaces 82A and 82B formed in each of the grooved throttle channels 83 adjacent to each other by the inclined ribs 82 on both sides. When provided, one groove wall surface 82A facing the lower oil chamber 25A pressurized in the pressure side stroke of the oil reservoir chamber 24 forms an angle θa with respect to the circumferential direction of the annular portion 81, and the other groove wall surface 82B is annular. The angle is smaller than the angle θb formed with respect to the circumferential direction of the portion 81. As a result, the groove wall surface 82A of the inclined rib 82 that collides when the oil in the lower oil chamber 25A pressurized by the pressure-side throttle member 80A in the pressure-side stroke enters the groove-like throttle channel 83 of the pressure-side throttle member 80A is The resistance exerted on the oil is increased, and the damping force generated due to the flow path resistance of the compression side throttle member 80A is further increased. On the other hand, the oil entering the groove-shaped throttle channel 83 of the pressure side throttle member 80A from the oil chamber 25B above the pressure side throttle member 80A in the extension side stroke has a small resistance received from the groove wall surface 82B of the inclined rib 82 with which it collides. Thus, the oil chamber 25A is smoothly returned to the oil chamber 25A below the compression side restricting member 80A, and is prepared for reversal of the compression side.

  When the oil flowing from the lower oil chamber 25A to the upper oil chamber 25B through the pressure side throttle member 80A passes through the groove-like throttle channel 83 of the pressure side throttle member 80A, the angles θa and θb of the two groove wall surfaces 82A and 82B. And the difference in wall length along the flow direction of the groove wall surfaces 82A and 82B, the flow of oil flowing in contact with one groove wall surface 82A is different from the flow of oil flowing in contact with the other groove wall surface 82B. ,Become slow. For this reason, the flow on the side of the one groove wall surface 82A is drawn into the flow on the side of the other groove wall surface 82B in the groove-shaped restriction channel 83 of the compression side restriction member 80A, and for example, a right-handed screw flow is generated. . The right-handed screw flow generated in each of the plurality of groove-shaped throttle channels 83 provided on the outer periphery of the compression-side throttle member 80A causes the damper cylinder 21 from the groove-shaped throttle channels 83 toward the upper oil chamber 25B. It will flow around. The oil flowing out from each groove-like restricting channel 83 of the compression side restricting member 80A continues to be more reliably rectified without being disturbed and diffused in all directions around the damper cylinder 21, and the rectifying effect is further enhanced.

  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. For example, in the damper leg, the vehicle body side tube may be an inner tube and the axle side tube may be an outer tube.

  According to the present invention, a damper leg with a built-in damper and a spring leg with a built-in suspension spring are arranged in parallel, and the damper leg is attached to one of the vehicle body side and the axle side on the vehicle body side and the axle side. Insert the inner tube attached to the other side, place the damper inside the outer tube and the inner tube, suspend the damper cylinder of the damper to the center of the outer tube or inner tube attached to the vehicle body side, and attach it to the axle side The piston rod of the piston rod standing at the center of the inner tube or the outer tube is inserted into the damper cylinder, and the outside of the damper serves as an oil reservoir chamber, and a compression side throttle member is provided on the outer periphery of the damper cylinder at the damper leg. The compression side throttle member is provided with an annular portion attached to the outer periphery of the damper cylinder, and an outer surface of the annular portion. A plurality of ribs provided in each of a plurality of positions along the direction and extending in the axial direction of the annular portion, forming a groove-shaped throttle channel between adjacent ribs, The compression side damping force generated by the damper leg damper is caused by the compression side damping force generated by the flow path resistance exerted on the hydraulic oil in the oil reservoir chamber by the compression passage of the compression side throttle member in the damper leg at a high speed and a large stroke. It made up for the lack of reaction force against the spring reaction force of the legs. As a result, it is possible to compensate for the lack of reaction force of the damper leg against the spring leg while reducing the weight and cost of the front fork.

A Front fork 10 Damper leg 11 Car body side tube 12 Axle side tube 20 Damper 21 Damper cylinder 22 Piston rod 23 Piston 24 Oil reservoir chamber 25 Oil chamber 26 Air chamber 40 Extension side damping force generator 50 Compression side damping force generator 60, 60A 80, 80A Pressure side throttle member 61, 81 Annular portion 62, 82 Rib 63, 83 Throttle channel 82A, 82B Groove wall surface 110 Spring leg 150 Suspension spring

Claims (5)

A damper leg with a built-in damper and a spring leg with a built-in suspension spring are arranged in parallel.
The damper leg is inserted into the outer tube attached to one of the vehicle body side and the axle side, and the inner tube attached to the other of the vehicle body side and the axle side is inserted, and the damper is disposed inside the outer tube and the inner tube. The cylinder is hung in the center of the outer tube or inner tube attached to the vehicle body, and the piston rod piston standing in the center of the inner tube or outer tube attached to the axle is inserted into the damper cylinder. A front fork that serves as an oil reservoir,
A compression side throttle member is provided on the outer periphery of the damper cylinder in the damper leg,
The compression side throttle member includes an annular portion attached to the outer periphery of the damper cylinder, and a plurality of ribs provided at each of a plurality of positions along the circumferential direction of the outer surface of the annular portion and extending in the axial direction of the annular portion. , Forming a groove-shaped throttle channel between adjacent ribs,
Generated by the damper leg damper due to the compression side damping force generated by the flow path resistance exerted on the hydraulic oil in the oil reservoir chamber by the throttle flow path of the compression side throttle member at the damper leg at a high piston speed and a large stroke in the compression stroke. A front fork in which the compression side damping force compensates for insufficient reaction force against the spring reaction force of the spring legs.   2. The front fork according to claim 1, wherein the rib forming the throttle channel of the compression side throttle member is an inclined rib that is inclined and extends in a direction along the axial direction of the annular portion.   The front fork according to claim 2, wherein the annular portion of the compression side throttle member is rotatably attached to the outer periphery of the damper cylinder.   One groove wall faced to the side pressurized by the pressure side stroke of the oil reservoir chamber when two groove wall surfaces forming respective grooved throttle channels adjacent to each other by the inclined ribs of the pressure side throttle member are provided. 4. The front fork according to claim 2, wherein the angle formed with respect to the circumferential direction of the annular portion is smaller than the angle formed with the other groove wall surface with respect to the circumferential direction of the annular portion.   Between the inclined ribs adjacent to each other across the throttle channel of the compression side throttle member, a groove wall surface forming the throttle channel of one inclined rib and a groove forming the throttle channel of the other inclined rib The front fork according to any one of claims 2 to 4, wherein the wall surface partially overlaps with the annular portion when viewed in the axial direction.

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