JP2012092945A - Front fork - Google Patents

Abstract

PROBLEM TO BE SOLVED: To greatly reduce weight and to improve workability by eliminating the use of a suspension spring including metal spring in a front fork in which a damper leg and a spring leg are arranged parallel.SOLUTION: The front fork A includes a damper leg 10 and a spring leg 110 arranged parallel. The spring leg 110 is constructed by inserting a vehicle body side tube 111 and an axle side tube 112 into each other, disposing a guide cylinder 121 at the center inside one of the vehicle body side tube 111 and the axle side tube 112, and inserting the guide 123 of a guide rod 122 disposed at the center inside the other of the vehicle body side tube 111 and the axle side tube 112 into the guide cylinder 121. The front fork A has: an inner air spring chamber 150 sectioned, inside the guide cylinder 121, by the guide 123 of the guide rod 122; and an external air spring chamber 160 sectioned, at least outside the inner air spring chamber 150 in the guide cylinder 121, by the vehicle body side tube 111 and the axle side tube 112.

Description

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

  Conventionally, as disclosed in Patent Document 1, as a front fork, a spring leg without a built-in damper and a suspension spring made of a metal spring, and a damper leg with a built-in damper and a built-in suspension spring made of a metal spring, Are arranged in parallel.

  The front fork described in Patent Document 1 does not include a damper in the spring leg, and does not include a suspension spring made of a metal spring in the damper leg, thereby simplifying the overall structure of the front fork, reducing the weight, and reducing the cost. It is intended to reduce.

49-1162

  The front fork described in Patent Document 1 has a suspension spring made of a metal spring intensively incorporated in one of the two legs, but the single metal spring incorporated in the spring leg It is necessary to secure sufficient spring strength to suspend the vehicle weight, and the effect of weight reduction by integrating metal springs is small.

  Further, in the spring leg, the suspension spring comes into sliding contact with the vehicle body side tube or the axle side tube from the metal spring, and there is a risk of friction, damage, generation of wear powder, and abnormal noise between the tube and the suspension spring.

  An object of the present invention is to eliminate a suspension spring made of a metal spring in a front fork in which a damper leg and a spring leg are arranged in parallel, and to greatly reduce the weight and improve the operability.

  The invention according to claim 1 does not include a suspension spring composed of a damper and a metal spring, and includes a spring leg incorporating a suspension spring composed of an air spring, and a damper leg incorporating a damper and not incorporating a suspension spring composed of a metal spring. Are arranged in parallel with each other, and a spring leg inserts the vehicle body side tube and the axle side tube into each other, and a guide cylinder is provided in the center of one of the vehicle body side tube and the axle side tube. An inner air spring chamber in which the guide rod guide provided in the center of the other inside of the axle side tube is inserted into the guide cylinder, and the guide rod guide is defined inside the guide cylinder, the body side tube and the axle side tube Has at least an outer air spring chamber defined outside the inner air spring chamber in the guide cylinder. Is obtained in such a manner that Te.

  The invention according to claim 2 is the invention according to claim 1, wherein the spring leg further adjusts the air pressure of the inner air spring chamber and the air pressure of the outer air spring chamber. And an outside air pressure adjusting unit.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the spring leg is a spring receiver provided on the outer periphery of the guide cylinder outside the guide cylinder, and a vehicle body side tube or an axle side tube. It consists of a metal spring interposed between a tube with a guide rod and contracts the body side tube and axle side tube against the spring force of the air spring in the outer air spring chamber and the air spring in the inner air spring chamber. It has a balance spring that urges it in the direction of movement.

  The invention according to claim 4 is the rod guide according to any one of claims 1 to 3, wherein the spring leg is provided in the guide cylinder inside the guide cylinder and inserts and supports the guide rod; It consists of a metal spring interposed between the guide rod guides inserted into the guide cylinder, and is compressed on the extending side of the vehicle body side tube and the axle side tube so that the vehicle body side tube and the axle side tube are contracted. It has a rebound spring that biases it.

  The invention according to claim 5 is the rod guide according to any one of claims 1 to 4, wherein the spring leg is provided in the guide cylinder and inserts and supports the guide rod inside the guide cylinder; A rebound air spring chamber is provided that is sandwiched and defined by a guide rod guide inserted into the guide cylinder.

  The invention according to claim 6 is the invention according to claim 5, wherein the spring leg further comprises a rebound air pressure adjusting portion for adjusting the air pressure of the rebound air spring chamber.

  The invention according to claim 7 is the invention according to any one of claims 1 to 6, wherein the damper leg further inserts the vehicle body side tube and the axle side tube into each other, and the damper cylinder is located at the center inside the vehicle body side tube. A rod guide that is provided in the guide cylinder of the spring leg and is inserted into and supported by the guide cylinder of the spring leg in a front view of the front fork. The bush of the rod guide and the bush of the rod guide provided in the damper cylinder of the damper leg for inserting and supporting the piston rod are positioned at the same height position.

  The invention according to claim 8 is the invention according to claim 7, and further, the vehicle body side tube of the spring leg and the vehicle body side tube of the damper leg have the same diameter, and the axle side tube of the spring leg and the axle side of the damper leg. The tube has the same diameter, the spring leg guide cylinder and the damper leg damper cylinder have the same diameter, and the spring leg guide rod and damper leg piston rod have the same diameter.

(Claim 1)
(a) The suspension spring built in the spring leg is not a metal spring but an air spring. By not using a metal spring, the weight can be significantly reduced. Further, since there is no sliding contact of the metal spring with respect to the vehicle body side tube or the axle side tube, the operability can be improved without causing friction, damage, generation of wear powder, or abnormal noise between the tube and the metal spring.

  (b) An inner air spring chamber in which the guide of the guide rod is partitioned inside the guide cylinder, and an outer air spring in which the vehicle body side tube and the axle side tube are partitioned at least outside the inner air spring chamber in the guide cylinder. And a chamber. The air chamber provided in the inner space surrounded by the vehicle body side tube and the axle side tube in the spring leg is divided into an inner air spring chamber and an outer air spring chamber inside and outside the guide cylinder. Each of the inner air spring chamber and the outer air spring chamber becomes a small space corresponding to the two-divided portion and has a high compression ratio. The spring force F1 of the air spring of the inner air spring chamber and the air spring of the outer air spring chamber The spring force F2 is increased, and the overall air spring force (F1 + F2) of the spring leg can be increased.

  The inner air spring chamber and the outer air spring chamber are independent from each other. By changing the spring force F1, F2 of the air spring in each spring chamber, the initial spring load can be adjusted and the free length of the front fork can be adjusted. The body posture can be changed by adjustment.

  (c) The air pressure of the inner air spring chamber and the outer air spring chamber are equal to the amount of the air spring force (F1 + F2) of the entire spring leg shared by the spring force F1 of the inner air spring chamber and the spring force F2 of the outer air spring chamber. The overall air spring force (F1 + F2) can be increased while reducing the air pressure. Thereby, a certain air spring force characteristic can be secured while reducing the seal load exerted on the seal member of the inner air spring chamber and the seal member of the outer air spring chamber.

  (d) Since the inner air spring chamber and the outer air spring chamber are independent from each other, the tube damage may occur due to chipping or the like that the stone hits the vehicle body side tube or the axle side tube. Even if it is damaged and the air pressure in the outer air spring chamber is lost, the load of about one passenger can be supported by the spring force of the inner air spring chamber and can continue running.

(Claim 2)
(e) The spring leg includes an inner air pressure adjusting unit for adjusting the air pressure of the inner air spring chamber and an outer air pressure adjusting unit for adjusting the air pressure of the outer air spring chamber. By adjusting the air pressure of the inner air spring chamber and the air pressure of the outer air spring, the air spring force characteristics of the entire spring leg can be variously changed.

(Claim 3)
(f) A spring leg is a metal spring interposed between the spring receiver provided on the outer periphery of the guide cylinder outside the guide cylinder and the tube on the vehicle body side tube or the axle side tube and provided with the guide rod. And a balance spring that urges the vehicle body side tube and the axle side tube in a contracting direction against the spring force of the air spring of the outer air spring chamber and the air spring of the inner air spring chamber. The spring leg is in an initial state in which a free length is formed in both directions of expansion and contraction at a position where the entire air spring force (F1 + F2) of the inner air spring chamber and the outer air spring chamber balances with the spring force Fb of the balance spring. As a result, it is possible to obtain a spring characteristic with good riding comfort without increasing the spring force in the initial to intermediate range of the expansion / contraction stroke. And the spring force of the latter half of an expansion-contraction stroke can be enlarged by the rise of the spring force of the air spring of an inner side air spring chamber and an outer side air spring chamber, and the spring force characteristic with a strut can be acquired.

(Claim 4)
(g) A metal spring interposed between a rod guide provided in the guide cylinder for inserting and supporting the guide rod inside the guide cylinder and a guide for the guide rod inserted in the guide cylinder inside the guide cylinder. And a rebound spring that is compressed on the extending side of the vehicle body side tube and the axle side tube and biases the body side tube and the axle side tube in a contracting direction. The spring leg is a position where the entire air spring force (F1 + F2) of the inner air spring chamber and the outer air spring chamber and the spring force Fr of the rebound spring (or the total spring force Fb + Fr of Fb and Fr in (f) above) are balanced. Thus, an initial state in which a free length is formed in both directions of expansion and contraction is obtained. As a result, it is possible to obtain a spring characteristic with good riding comfort without increasing the spring force in the initial to intermediate range of the expansion / contraction stroke. And the spring force of the latter half of an expansion-contraction stroke can be enlarged by the rise of the spring force of the air spring of an inner side air spring chamber and an outer side air spring chamber, and the spring force characteristic with a strut can be acquired.

(Claim 5)
(h) Rebound air in which a spring leg is defined by being sandwiched between a rod guide provided in the guide cylinder for inserting and supporting the guide rod and a guide for the guide rod inserted in the guide cylinder inside the guide cylinder. It has a spring chamber. The spring leg is in an initial state in which a free length is formed in both the expansion and contraction directions at a position where the entire air spring force (F1 + F2) of the inner air spring chamber and the outer air spring chamber is balanced with the spring force F3 of the rebound air spring chamber. As a result, it is possible to obtain a spring characteristic with good riding comfort without increasing the spring force in the initial to intermediate range of the expansion / contraction stroke. And the spring force of the latter half of an expansion-contraction stroke can be enlarged by the rise of the spring force of the air spring of an inner side air spring chamber and an outer side air spring chamber, and the spring force characteristic with a strut can be acquired.

(Claim 6)
(i) The spring leg has a rebound air pressure adjusting unit for adjusting the air pressure of the rebound air spring chamber. By adjusting the air pressure of the rebound air spring chamber, the air spring force characteristics of the entire spring leg can be variously changed.

(Claim 7)
(j) In front view of the front fork, a rod guide bush provided on the guide cylinder of the spring leg for inserting and supporting the guide rod, and a rod guide provided on the damper cylinder of the damper leg for inserting and supporting the piston rod Are located at the same height position. The balance between the rigidity of the damper leg and the spring leg can be balanced, and the swinging (yaw direction) of the handle during disturbance input can be suppressed.

(Claim 8)
(k) The spring leg body side tube and damper leg body side tube have the same diameter, the spring leg axle side tube and damper leg axle side tube have the same diameter, and the spring leg guide cylinder and damper leg The damper cylinder has the same diameter, and the spring leg guide rod and the damper leg piston rod have the same diameter. The balance between the rigidity of the damper leg and the spring leg can be balanced, and the swinging (yaw direction) of the handle during disturbance input can be suppressed.

FIG. 1 is a cross-sectional view showing a front fork of the first embodiment. FIG. 2 is a cross-sectional view showing the damper leg. FIG. 3 is a lower cross-sectional view of FIG. 4 is a top sectional view of FIG. FIG. 5 is a sectional view showing the spring leg. 6 is a lower cross-sectional view of FIG. FIG. 7 is a top sectional view of FIG. FIG. 8 is a diagram showing the spring force characteristics of the spring legs. FIG. 9 is a cross-sectional view showing the front fork of the second embodiment. FIG. 10 is a cross-sectional view showing the spring leg. FIG. 11 is a lower cross-sectional view of FIG. 12 is a top sectional view of FIG. FIG. 13 is a diagram showing the spring force characteristics of the spring legs.

Example 1 (FIGS. 1 to 8)
The front fork A includes a damper 20 and a damper leg 10 that does not include a suspension spring made of a metal spring. A front fork A does not include a suspension spring that includes a damper and a metal spring, and an air spring (the air spring of the inner air spring chamber 150). A spring leg 110 containing a suspension spring 140 made up of an air spring of the outer air spring chamber 160 is disposed in parallel.

(Damper leg 10) (FIGS. 1, 2 to 4)
As shown in FIGS. 1 and 2 to 4, the damper leg 10 is slid by sealing a vehicle body side tube (outer tube) 11 and an axle side tube (inner tube) 12 through bushes 13A and 13B and a seal member 13C. A single cylinder damper 20 is disposed inside the vehicle body side tube 11 and the axle side tube 12 so as to be freely movable. 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. A lower end portion of the piston rod 22 is screwed to a bottom bolt 32A that is engaged and sealed with the bottom portion of the axle bracket 32 from the outside, and is fixed by a lock nut 32B. The oil lock collar 33 </ b> A is clamped between the lower end surface of the axle tube 12 and the bottom of the axle bracket 32. The piston rod 22 is slidably supported by a bush 35 and a seal member 36 of a rod guide 34 screwed into a lower opening end of the damper cylinder 21 and is inserted into the damper cylinder 21. 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. Due to the damping force generated by the main valve device 40 and the sub valve device 50, the damper 20 expands and contracts vibrations of the vehicle body side tube 111 and the axle side tube 112 due to absorption of impact force by air springs (described later) of the suspension spring 140 of the spring leg 110. To suppress vibration.

(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, 5 to 8)
As shown in FIGS. 1 and 5-8, the spring leg 110 is slid by sealing the vehicle body side tube (outer tube) 111 and the axle side tube (inner tube) 112 through bushes 113A and 113B and a seal member 113C. Insert freely. The spring leg 110 suspends the guide cylinder 121 in the center of the vehicle body side tube 111, and the tip guide 123 of the guide rod 122 erected in the center of the axle side tube 112 is slidably inserted into the guide cylinder 121. is doing.

  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 cap 130 and a fork bolt 131. The cap 130 is screwed to the vehicle body side tube 111, and the fork bolt 131 is screwed to the cap 130. A guide cylinder 121 is connected to and suspended from the lower end of the cap 130. A steady collar 121 </ b> A is attached to the outer periphery of the lower end side of the guide cylinder 121 via the inner periphery of the axle tube 112 and an annular gap.

  An axle bracket 132 is screwed and sealed to the lower end portion of the axle tube 112, and the bottom piece 133 is held between the lower end surface of the axle tube 112 and the bottom surface of the axle bracket 132. And the lower end part of the guide rod 122 is standingly arranged in the center part of the axle bracket 132 inside the axle side tube 112. The lower end portion of the guide rod 122 is screwed to a bottom bolt 134 that is engaged and sealed from the outside to the bottom portion of the axle bracket 132 and is fixed by a lock nut 135. The guide rod 122 is slidably supported by a bush 137 of a rod guide 136 screwed into the lower opening end of the guide cylinder 121 and is inserted into the guide cylinder 121. A guide 123 is screwed to the tip of a guide rod 122 inserted into the guide cylinder 121.

  The spring leg 110 includes an inner air spring chamber 150 in which the tip guide 123 of the guide rod 122 is defined inside the guide cylinder 121, and the vehicle body side tube 111 and the axle side tube 112 are at least outside the inner air spring chamber 150 in the guide cylinder 121. And an outer air spring chamber 160 which is divided into two. Thereby, the spring leg 110 constitutes the suspension spring 140 by the air spring of the inner air spring chamber 150 and the air spring of the outer air spring chamber 160.

  The inner air spring chamber 150 is partitioned by a fork bolt 131 and a tip guide 123 of the guide rod 122 inside the guide cylinder 121 where the guide rod 122 does not exist. The inner air spring chamber 150 is hermetically sealed by a seal member 151 provided with the tip guide 123 with respect to the inner periphery of the guide cylinder 121 and a seal member 152 provided with the fork bolt 131 with respect to the inner periphery of the cap 130. The

  The air pressure in the inner air spring chamber 150 is adjusted by the inner air pressure adjusting unit 153. The inner air pressure adjusting unit 153 includes an air valve attached at a position facing the outside of the fork bolt 131, communicates with the inner air spring chamber 150 through a hole 154 drilled in the fork bolt 131, and Adjust the enclosed air pressure. The inner air pressure adjusting unit 153 may be made of a rubber film that can be pierced by an injection needle of a pneumatic injector. A cover 155 attached to and detached from the fork bolt 131 from the outside covers the inner air pressure adjusting unit 153.

  The outer air spring chamber 160 inserts the guide rod 122 inside the space 161 where the vehicle body side tube 111 and the axle side tube 112 are partitioned outside the guide cylinder 121 and the guide cylinder 121 on the side where the guide rod 122 exists. A space 162 is defined by being sandwiched by a rod guide 136 to be supported and a tip guide 123 of the guide rod 122, and communicated with the space 161 through a hole 162 </ b> A provided in the guide cylinder 121. The space 162 also includes a hollow portion 122A of the guide rod 122 in the present embodiment. The vehicle body side tube 111 and the axle side tube 112 slide in an airtight manner on the sliding portions via the above-described seal member 113C. At the upper part of the space 161 (including holes 168 and 169 described later), a seal member 163A provided with the cap 130 with respect to the inner periphery of the vehicle body side tube 111 and a fork bolt 131 provided with respect to the inner periphery of the cap 130 It is hermetically sealed by the seal member 163B. In the lower part of the space 161, the bottom piece 133 is provided with seal members 164A and 164B provided on the inner periphery of the axle side tube 112 and the bottom surface of the axle bracket 132, and the bottom bolt 134 is provided with a seal provided on the inner periphery of the axle bracket 132. The member 165 is hermetically sealed. Further, the space 162 is hermetically sealed by a seal member 166 provided with the tip guide 123 with respect to the inner periphery of the guide cylinder 121.

  The outer air spring chamber 160 may be composed of only the space 161. At this time, the space 162 does not communicate with the space 161 and can be released to the outside through the hollow portion 122 </ b> A of the guide rod 122.

  The air pressure of the outer air spring chamber 160 is adjusted by the outer air pressure adjusting unit 167. The outer air pressure adjusting unit 167 is formed of an air valve attached at a position facing the outside of the fork bolt 131, a hole 168 provided in the fork bolt 131, an annular gap between the cap 130 and the fork bolt 131, and the cap 130. The hole 169 communicates with the space 161, and consequently the space 162, and adjusts the sealed air pressure of the outer air spring chamber 160 (spaces 161 and 162). The outer air pressure adjusting unit 167 may be made of a rubber film that can be pierced by an injection needle of a pneumatic injector. The above-described cover 155 that is attached to and detached from the fork bolt 131 from the outside covers the outer air pressure adjusting unit 167.

  The spring leg 110 forms an air spring by the inner air spring chamber 150 and the outer air spring chamber 160 which are compressed in the compression side stroke. The spring force F1 (FIG. 8) of the air spring in the inner air spring chamber 150 and the spring force F2 (FIG. 8) of the air spring in the outer air spring chamber 160 are biased in the direction in which the vehicle body side tube 111 and the axle side tube 112 are extended. To do.

  The spring leg 110 can form an oil chamber in which lubricating oil is loaded below the outer air spring chamber 160. The sliding portions of the vehicle body side tube 111 and the axle side tube 112 and the sliding portions of the guide cylinder 121 and the guide rod 122 are lubricated.

  The spring leg 110 is a balance spring between the spring receiver 171 provided on the outer periphery of the guide cylinder 121 and the spring receiver 172 provided at the upper end opening of the axle-side tube 112 on which the guide rod 122 is erected. 170 is interposed. The balance spring 170 is a metal coil spring. The spring force Fb (FIG. 8) of the metal spring of the balance spring 170 is biased by the spring forces F1 and F2 of the air springs in the inner air spring chamber 150 and the outer air spring chamber 160 in the vehicle body side tube 111 and the axle side tube 112. The vehicle body side tube 111 and the axle side tube 112 are contracted against the spring force F1 of the air spring in the inner air spring chamber 150 and the spring force F2 of the air spring in the outer air spring chamber 160. Energize in the direction.

  The spring leg 110 is provided inside the guide cylinder 121, provided on the guide cylinder 121, provided on the inner end surface of the rod guide 136 that inserts and supports the guide rod 122, and the guide rod 122 inserted in the guide cylinder 121. The rebound spring 180 is interposed between the spring receiver 182 that abuts against the tip guide 123 (the space 162 described above). The rebound spring 180 is a metal coil spring. The spring force Fr (FIG. 8) of the metal spring of the rebound spring 180 is urged by the spring forces F1 and F2 of the air springs in the inner air spring chamber 150 and the outer air spring chamber 160 in the vehicle body side tube 111 and the axle side tube 112. The vehicle body side tube 111 and the axle side tube 112 are contracted against the spring force F1 of the air spring in the inner air spring chamber 150 and the spring force F2 of the air spring in the outer air spring chamber 160. Energize in the direction.

  Therefore, in the front fork A, the spring force F1 of the air spring of the inner air spring chamber 150 that urges the vehicle body side tube 111 and the axle side tube 112 with respect to the expansion / contraction stroke of the spring leg 110 and the outer air. The spring force F2 of the air spring in the spring chamber 160, the spring force Fb of the metal spring of the balance spring 170 that urges the vehicle body side tube 111 and the axle side tube 112 in the contraction direction on the extended side, and the metal spring of the rebound spring 180 The spring force Fr is generated as shown in FIG. 8, and a combined spring force F that is the sum of them is generated. The combined spring force F increases the latter half of the spring force without increasing the spring force in the initial to intermediate range of the expansion / contraction stroke.

  In the front fork A, the expansion and contraction vibration of the vehicle body side tube 111 and the vehicle body side tube 112 due to the absorption of the impact force by the above-described combined spring force F of the spring leg 110 is caused by the expansion side of the damper leg 10 in the damper 20. The damping force is suppressed by the damping force generated by the extension side damping valve 42A of the damping force generation device 40 and the compression side damping valve 54A of the compression side damping force generation device 50.

  In the front fork A, the piston rod 22 of the damper leg 10 and the guide rod 122 of the spring leg 110 are made hollow to reduce the weight of the damper leg 10 and the spring leg 110.

  Further, in the front fork A, the vehicle body side tube 11 of the damper leg 10 and the vehicle body side tube 111 of the spring leg 110 have the same length and the same diameter (the same diameter) in order to balance the rigidity of the damper leg 10 and the spring leg 110. The piston rod 22 of the damper leg 10 and the guide rod 122 of the spring leg 110 have the same length and the same diameter (same thickness). Further, the damper cylinder 21 of the damper leg 10 and the guide cylinder 121 of the spring leg 110 have the same length and the same diameter (the same thickness), and the piston rod 22 of the damper leg 10 and the guide rod 122 of the spring leg 110 have the same length. , Have the same diameter (same thickness).

  Further, in the front fork A, in order to balance the rigidity of the damper leg 10 and the spring leg 110, the piston rod is provided on the damper cylinder 21 of the damper leg 10 in a front view of the front fork A (FIG. 1). The bush 35 of the rod guide 34 that inserts and supports the rod 22 and the bush 137 of the rod guide 136 that is provided on the guide cylinder 121 of the spring leg 110 and inserts and supports the guide rod 122 are positioned at the same height position. Also, a bush 13A provided on the vehicle body side tube 11 of the damper leg 10 for inserting and supporting the axle side tube 12 and a bush 113A provided on the vehicle body side tube 111 of the spring leg 110 for inserting and supporting the axle side tube 112. Are positioned at the same height position.

According to the present embodiment, the following operational effects can be obtained.
(a) The suspension spring 140 built in the spring leg 110 is not a metal spring but an air spring (the inner air spring chamber 150 and the outer air spring chamber 160). By not using a metal spring, the weight can be significantly reduced. In addition, since there is no sliding contact of the metal spring with respect to the vehicle body side tube 111 and the axle side tube 112, there is no friction between the tubes 111, 112 and the metal spring, damage, generation of wear powder, noise, and operation. Can be improved.

  (b) The spring leg 110 includes an inner air spring chamber 150 in which the guide 123 of the guide rod 122 is defined inside the guide cylinder 121, and the vehicle body side tube 111 and the axle side tube 112 are at least the inner air spring chamber in the guide cylinder 121. 150 and an outer air spring chamber 160 that is partitioned outside 150. The air chamber provided in the inner space surrounded by the vehicle body side tube 111 and the axle side tube 112 in the spring leg 110 is divided into an inner air spring chamber 150 and an outer air spring chamber 160 inside and outside the guide cylinder 121. Each of the inner air spring chamber 150 and the outer air spring chamber 160 becomes a small space by the amount of being divided into a high compression ratio, and the spring force F1 of the air spring of the inner air spring chamber 150 and the outer air spring chamber The spring force F2 of the 160 air spring is increased, and the overall air spring force (F1 + F2) of the spring leg 110 can be increased.

  The inner air spring chamber 150 and the outer air spring chamber 160 are independent from each other, and by changing the spring force F1, F2 of the air spring of each of the spring chambers 150, 160, the initial spring load can be adjusted, The body posture can be changed by adjusting the free length of the fork A.

  (c) The air spring force (F1 + F2) of the entire spring leg 110 is divided into the spring force F1 of the inner air spring chamber 150 and the spring force F2 of the outer air spring chamber 160, and the air pressure of the inner air spring chamber 150 The overall air spring force (F1 + F2) can be increased while reducing the air pressure in the outer air spring chamber 160. Accordingly, it is possible to ensure a certain air spring force characteristic while reducing the seal load exerted on the seal members 151 and 152 of the inner air spring chamber 150 and the seal members 113C, 163, 164, 165 and 166 of the outer air spring chamber 160. .

  (d) Since the inner air spring chamber 150 and the outer air spring chamber 160 are independent from each other, the tube is damaged by chipping or the like that the stone hits the vehicle body side tube 111 or the axle side tube 112, and consequently the outer air spring chamber. Even if the seal member 113C of 160 is damaged and the air pressure of the outer air spring chamber 160 is released, the load of about one passenger can be supported by the spring force of the inner air spring chamber 150 and can continue running.

  (e) The spring leg 110 has an inner air pressure adjusting unit 153 for adjusting the air pressure of the inner air spring chamber 150 and an outer air pressure adjusting unit 167 for adjusting the air pressure of the outer air spring chamber 160. By adjusting the air pressure of the inner air spring chamber 150 and the air pressure of the outer air spring, the entire air spring force characteristic of the spring leg 110 can be variously changed.

  (f) The spring leg 110 is located between the spring receiver 171 provided on the outer periphery of the guide cylinder 121 outside the guide cylinder 121 and the tube on the vehicle body side tube 111 or the axle side tube 112 and provided with the guide rod 122. It is composed of an intervening metal spring and biases the vehicle body side tube 111 and the axle side tube 112 in a contracting direction against the spring force of the air spring of the outer air spring chamber 160 and the air spring of the inner air spring chamber 150. A balance spring 170 is provided. The spring leg 110 is in an initial state in which a free length is formed in both the expansion and contraction directions at a position where the overall air spring force (F1 + F2) of the inner air spring chamber 150 and the outer air spring chamber 160 balances with the spring force Fb of the balance spring 170. Become. As a result, it is possible to obtain a spring characteristic with good riding comfort without increasing the spring force in the initial to intermediate range of the expansion / contraction stroke. Then, the spring force in the latter half of the expansion / contraction stroke is increased by the rise of the spring force of the air springs in the inner air spring chamber 150 and the outer air spring chamber 160, and a spring force characteristic with struts can be obtained.

  (g) A rod leg 136 is provided in the guide cylinder 121 inside the guide cylinder 121 to insert and support the guide rod 122, and a guide 123 of the guide rod 122 inserted in the guide cylinder 121. It has a rebound spring 180 made of a metal spring interposed between them and compressed on the extending side of the vehicle body side tube 111 and the axle side tube 112 to urge the vehicle body side tube 111 and the axle side tube 112 in a contracting direction. . The spring leg 110 includes the entire air spring force (F1 + F2) of the inner air spring chamber 150 and the outer air spring chamber 160 and the spring force Fr of the rebound spring 180 (or the total spring force Fb + Fr of Fb and Fr in (f) above). In an initial state of free length in both directions of expansion and contraction at a position where and are balanced. As a result, it is possible to obtain a spring characteristic with good riding comfort without increasing the spring force in the initial to intermediate range of the expansion / contraction stroke. Then, the spring force in the latter half of the expansion / contraction stroke is increased by the rise of the spring force of the air springs in the inner air spring chamber 150 and the outer air spring chamber 160, and a spring force characteristic with struts can be obtained.

  (h) In front view of the front fork A, the piston 137 is provided on the bushing 137 of the rod guide 136 that is provided on the guide cylinder 121 of the spring leg 110 to insert and support the guide rod 122 and on the damper cylinder 21 of the damper leg 10. The bush 35 of the rod guide 34 for inserting and supporting the rod 22 is positioned at the same height position. The balance between the rigidity of the damper leg 10 and the spring leg 110 can be balanced, and the swing of the handle (yaw direction) at the time of disturbance input can be suppressed.

  (i) The vehicle body side tube 111 of the spring leg 110 and the vehicle body side tube 11 of the damper leg 10 have the same diameter, and the axle side tube 112 of the spring leg 110 and the axle side tube 12 of the damper leg 10 have the same diameter, The guide cylinder 121 of the leg 110 and the damper cylinder 21 of the damper leg 10 have the same diameter, and the guide rod 122 of the spring leg 110 and the piston rod 22 of the damper leg 10 have the same diameter. The balance between the rigidity of the damper leg 10 and the spring leg 110 can be balanced, and the swing of the handle (yaw direction) at the time of disturbance input can be suppressed.

Example 2 (FIGS. 9 to 13)
As shown in FIG. 9, the front fork B of the second embodiment has a damper leg 10 and a spring leg 210 arranged in parallel. The damper leg 10 is the same as the damper leg 10 used in the front fork A of the first embodiment. The spring leg 210 is substantially the same as the spring leg 110 used in the front fork A of the first embodiment, does not include a suspension spring composed of a damper and a metal spring, and is an air spring (the air spring and the outer side of the inner air spring chamber 230). A suspension spring 220 including an air spring in the air spring chamber 240 and an air spring in the rebound air spring chamber 250 is incorporated.

  Since the damper leg 10 in the front fork B is the same as the damper leg 10 in the front fork A, description thereof is omitted.

  The spring leg 210 in the front fork B is the same as the spring leg 110 in the front fork A except for the suspension spring 220, as shown in FIGS. Is omitted. The spring leg 210 in the front fork B constitutes the suspension spring 220 as follows.

  The spring leg 210 has an inner air spring chamber 230 in which the tip guide 123 of the guide rod 122 is defined inside the guide cylinder 121, and the vehicle body side tube 111 and the axle side tube 112 are outside the inner air spring chamber 230 in the guide cylinder 121. And an outer air spring chamber 240 to be partitioned. In addition, the spring leg 210 is provided inside the guide cylinder 121 to a rod guide 136 that is provided in the guide cylinder 121 to insert and support the guide rod 122 and a tip guide 123 of the guide rod 122 inserted into the guide cylinder 121. It has a rebound air spring chamber 250 that is sandwiched and partitioned. Thereby, the spring leg 210 constitutes the suspension spring 220 by the air spring of the inner air spring chamber 230, the air spring of the outer air spring chamber 240, and the air spring of the rebound air spring chamber 250.

  The inner air spring chamber 230 is partitioned by a fork bolt 131 and a tip guide 123 of the guide rod 122 inside the guide cylinder 121 where the guide rod 122 does not exist. The inner air spring chamber 230 is hermetically sealed by a seal member 231 provided with the tip guide 123 with respect to the inner periphery of the guide cylinder 121 and a seal member 232 with a fork bolt 131 provided with respect to the inner periphery of the cap 130. The

  The air pressure in the inner air spring chamber 230 is adjusted by the inner air pressure adjusting unit 233. The inner air pressure adjusting unit 233 is an air valve that is attached to a position facing the outside of the fork bolt 131 and communicates with the inner air spring chamber 230, and adjusts the enclosed air pressure of the inner air spring chamber 230. The inner air pressure adjusting unit 233 may be made of a rubber film that can be pierced by an injection needle of a pneumatic injector. A cover 233 </ b> A attached to the fork bolt 131 from the outside covers the inner air pressure adjusting unit 233.

  The outer air spring chamber 240 is a space defined by the vehicle body side tube 111 and the axle side tube 112 outside the guide cylinder 121. The vehicle body side tube 111 and the axle side tube 112 slide in an airtight manner on the sliding portions via the above-described seal member 113C. The upper part of the outer air spring chamber 240 (including holes 248 and 249 described later) is provided with a seal member 241A provided with the cap 130 on the inner periphery of the vehicle body side tube 111, and a fork bolt 131 with respect to the inner periphery of the cap 130. The sealing member 241 </ b> B provided is hermetically sealed. The lower part of the outer air spring chamber 240 has a bottom piece 133 on the inner periphery of the axle-side tube 112, seal members 243A and 243B provided on the bottom surface of the axle bracket 132, and a bottom bolt 134 on the inner periphery of the axle bracket 132. The seal member 244 provided is hermetically sealed. The outer air spring chamber 240 is also hermetically sealed by a seal member 245 provided to the outer periphery of the guide rod 122 by the rod guide 136.

  The air pressure in the outer air spring chamber 240 is adjusted by the outer air pressure adjusting unit 247. The outer air pressure adjusting unit 247 is composed of an air valve attached at a position facing the outside of the fork bolt 131, a hole 248 provided in the fork bolt 131, an annular gap between the cap 130 and the fork bolt 131, and the cap 130. The outer air spring chamber 240 is communicated with a hole 249 provided in the outer air spring 249 to adjust the enclosed air pressure of the outer air spring chamber 240. The outer air pressure adjusting unit 247 may be made of a rubber film that can be pierced by an injection needle of a pneumatic injector. A cover 247 </ b> A attached to the fork bolt 131 from the outside covers the outer air pressure adjusting unit 247.

  The spring leg 210 forms an air spring by the inner air spring chamber 230 and the outer air spring chamber 240 which are compressed in the compression side stroke. The spring force F1 (FIG. 13) of the air spring in the inner air spring chamber 230 and the spring force F2 (FIG. 13) of the air spring in the outer air spring chamber 240 are biased in the direction in which the vehicle body side tube 111 and the axle side tube 112 are extended. To do.

  The spring leg 210 can form an oil chamber in which lubricating oil is loaded below the outer air spring chamber 240. The sliding portions of the vehicle body side tube 111 and the axle side tube 112 and the sliding portions of the guide cylinder 121 and the guide rod 122 are lubricated.

  As described above, the spring leg 210 is provided in the guide cylinder 121 inside the guide cylinder 121 to insert and support the guide rod 122 and the tip guide 123 of the guide rod 122 inserted into the guide cylinder 121. A rebound air spring chamber 250 that is sandwiched between the two. The rebound air spring chamber 250 is hermetically sealed by a seal member 251 provided with the tip guide 123 with respect to the inner periphery of the guide cylinder 121 and a seal member 252 provided with the rod guide 136 with respect to the outer periphery of the guide rod 122. The 252A is a seal presser.

  The air pressure of the rebound air spring chamber 250 is adjusted by the rebound air pressure adjusting unit 253. The rebound air pressure adjusting unit 253 is an air valve attached at a position facing the outside of the bottom bolt 134, and enters the rebound air spring chamber 250 via the hollow portion 122 </ b> A of the guide rod 122 and the hole 254 provided in the tip guide 123. In communication, the sealed air pressure of the rebound air spring chamber 250 is adjusted. The rebound air pressure adjusting unit 253 may be made of a rubber film that can be pierced by an injection needle of a pneumatic injector. A cover 235 </ b> A attached to and detached from the bottom bolt 134 from the outside covers the rebound air pressure adjusting unit 253.

  The spring leg 210 forms an air spring by the rebound air spring chamber 250 compressed on the extending side of the extending side stroke. The spring force F3 (FIG. 13) of the air spring of the rebound air spring chamber 250 is applied by the spring forces F1 and F2 of the air springs of the inner side air spring chamber 230 and the outer side air spring chamber 240. The body side tube 111 and the axle side tube 112 are compressed against the spring force F1 of the air spring of the inner air spring chamber 230 and the spring force F2 of the air spring of the outer air spring chamber 240 against the stretched side. Energize in the direction of contraction.

  Therefore, in the front fork B, the spring force F1 of the air spring of the inner air spring chamber 230 and the outer air are biased in the direction of causing the vehicle body side tube 111 and the axle side tube 112 to move with respect to the expansion / contraction stroke of the spring leg 210. FIG. 13 shows the spring force F2 of the air spring in the spring chamber 240 and the spring force F3 of the air spring in the rebound air spring chamber 250 that biases the vehicle body side tube 111 and the axle side tube 112 in the direction of contraction on the extended side. As shown, a combined spring force F is generated which is the sum of them. The combined spring force F increases the latter half of the spring force without increasing the spring force in the initial to intermediate range of the expansion / contraction stroke.

  In the front fork B, 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 above-described combined spring force F of the spring leg 210 is caused by the expansion side of the damper leg 10 in the damper 20. The damping force is suppressed by the damping force generated by the extension side damping valve 42A of the damping force generation device 40 and the compression side damping valve 54A of the compression side damping force generation device 50.

  In the front fork B, the piston rod 22 of the damper leg 10 and the guide rod 222 of the spring leg 210 are made hollow to reduce the weight of the damper leg 10 and the spring leg 210.

  In the front fork B, in order to balance the rigidity of the damper leg 10 and the spring leg 210, the vehicle body side tube 11 of the damper leg 10 and the vehicle body side tube 111 of the spring leg 210 have the same length and the same diameter (the same diameter). The piston rod 22 of the damper leg 10 and the guide rod 222 of the spring leg 210 have the same length and the same diameter (same thickness). The damper cylinder 21 of the damper leg 10 and the guide cylinder 221 of the spring leg 210 have the same length and the same diameter (same thickness), and the piston rod 22 of the damper leg 10 and the guide rod 222 of the spring leg 210 have the same length. , Have the same diameter (same thickness).

  Further, in the front fork B, in order to balance the rigidity of the damper leg 10 and the spring leg 210, the piston rod is provided on the damper cylinder 21 of the damper leg 10 in a front view of the front fork B (FIG. 9). The bush 35 of the rod guide 34 that inserts and supports the rod 22 and the bush 137 of the rod guide 136 that is provided in the guide cylinder 221 of the spring leg 210 and inserts and supports the guide rod 222 are positioned at the same height position. Also, a bush 13A provided on the vehicle body side tube 11 of the damper leg 10 for inserting and supporting the axle side tube 12 and a bush 113A provided on the vehicle body side tube 111 of the spring leg 110 for inserting and supporting the axle side tube 112. Are positioned at the same height position.

  According to the present embodiment, in addition to the operational effects (a) to (e), (h), and (i) of the first embodiment, the following operational effects are achieved.

  (j) A spring leg 210 is provided inside the guide cylinder 121 and is provided in the guide cylinder 121 to insert and support the guide rod 122, and a guide 123 of the guide rod 122 inserted into the guide cylinder 121. It has a rebound air spring chamber 250 that is sandwiched and partitioned. The spring leg 210 is a position where the entire air spring force (F1 + F2) of the inner air spring chamber 230 and the outer air spring chamber 240 balances with the spring force F3 of the rebound air spring chamber 250, and has a free length in both expansion and contraction directions. It becomes a state. As a result, it is possible to obtain a spring characteristic with good riding comfort without increasing the spring force in the initial to intermediate range of the expansion / contraction stroke. Then, the spring force in the latter half of the expansion / contraction stroke can be increased by the rise of the spring force of the air springs in the inner air spring chamber 230 and the outer air spring chamber 240, and a spring force characteristic with struts can be obtained.

  (k) The spring leg 210 has a rebound air pressure adjusting unit 253 for adjusting the air pressure of the rebound air spring chamber 250. By adjusting the air pressure of the rebound air spring chamber 250, the air spring force characteristics of the entire spring leg 210 can be variously changed.

  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, the axle side tube may be an outer tube, the damper cylinder may be provided on the axle side tube, and the piston rod may be provided on the vehicle body side tube.

  In the spring leg, the vehicle body side tube may be an inner tube and the axle side tube may be an outer tube.

  The present invention does not include a suspension spring composed of a damper and a metal spring, but includes a spring leg incorporating a suspension spring composed of an air spring and a damper leg incorporating a damper and not including a suspension spring composed of a metal spring. A front leg, a spring leg, the vehicle body side tube and the axle side tube are inserted into each other, a guide cylinder is provided in the center of one of the vehicle body side tube and the axle side tube, and the vehicle body side tube and the axle side tube are The guide rod guide provided in the center of the other inside is inserted into the guide cylinder, and the inner air spring chamber in which the guide rod guide is partitioned inside the guide cylinder, the vehicle body side tube and the axle side tube are in the guide cylinder. Having at least an outer air spring chamber partitioned outside the inner air spring chamber A. Thereby, in the front fork in which the damper leg and the spring leg are arranged in parallel, the suspension spring made of the metal spring is not used, and the weight can be significantly reduced and the operability can be improved.

A Front fork 10 Damper leg 11 Car body side tube 12 Axle side tube 13A Bush 20 Damper 21 Damper cylinder 22 Piston rod 23 Piston 34 Rod guide 35 Bush 110, 110A Spring leg 111 Car body side tube 112 Axle side tube 113A Bush 121 Guide cylinder 122 Guide rod 123 Guide 136 Rod guide 137 Bush 140 Suspension spring 150 Inner air spring chamber 153 Inner air pressure adjustment unit 160 Outer air spring chamber 167 Outer air pressure adjustment unit 170 Balance springs 171 and 172 Spring receiver 180 Rebound spring B Front fork 210 Spring leg 220 Suspension spring 230 Inner air spring chamber 233 Inner air pressure adjustment unit 240 Outer air spring chamber 247 Outer air pressure adjustment Part 250 rebound air spring chamber 253 rebound air pressure adjustment section

Claims (8)

A front fork that does not include a suspension spring consisting of a damper and a metal spring, but a spring leg that includes a suspension spring consisting of an air spring and a damper leg that includes a damper and does not include a suspension spring consisting of a metal spring. There,
Spring leg
A vehicle body side tube and an axle side tube are inserted into each other, a guide cylinder is provided at the center inside one of the body side tube and the axle side tube, and a guide rod provided at the center inside the other side of the body side tube and the axle side tube Insert the guide into the guide cylinder,
An inner air spring chamber in which a guide of the guide rod is defined inside the guide cylinder, and an outer air spring chamber in which the vehicle body side tube and the axle side tube are partitioned at least outside the inner air spring chamber in the guide cylinder. Front fork.   2. The front according to claim 1, wherein the spring leg includes an inner air pressure adjusting portion for adjusting the air pressure of the inner air spring chamber and an outer air pressure adjusting portion for adjusting the air pressure of the outer air spring chamber. fork.   The spring leg comprises a metal spring interposed between a spring receiver provided on the outer periphery of the guide cylinder outside the guide cylinder and a tube on the vehicle body side tube or axle side tube and provided with a guide rod. 3. A balance spring that urges the vehicle body side tube and the axle side tube in a contracting direction against the spring force of the air spring of the outer air spring chamber and the air spring of the inner air spring chamber. The described front fork.   The spring leg comprises a metal spring interposed between a rod guide provided in the guide cylinder for inserting and supporting the guide rod inside the guide cylinder and a guide for the guide rod inserted in the guide cylinder. The front according to any one of claims 1 to 3, further comprising a rebound spring that is compressed on the extending side of the vehicle body side tube and the axle side tube and urges the vehicle body side tube and the axle side tube in a contracting direction. fork.   A rebound air spring chamber in which the spring leg is defined between a rod guide provided in the guide cylinder for inserting and supporting the guide rod and a guide of the guide rod inserted in the guide cylinder inside the guide cylinder. The front fork according to claim 1, comprising:   The front fork according to claim 5, wherein the spring leg has a rebound air pressure adjusting portion for adjusting the air pressure of the rebound air spring chamber. The damper leg inserts the vehicle body side tube and the axle side tube into each other, the damper cylinder is provided at the center inside the vehicle body side tube, and the piston of the piston rod provided at the center inside the axle side tube is inserted into the damper cylinder. And
A rod guide bush provided in the guide cylinder of the spring leg for inserting and supporting the guide rod in a front view of the front fork, and a bush of the rod guide provided in the damper cylinder of the damper leg for inserting and supporting the piston rod. Are located in the same height position, The front fork in any one of Claims 1-6. The spring leg body side tube and the damper leg body side tube have the same diameter, and the spring leg axle side tube and damper leg axle side tube have the same diameter,
8. The front fork according to claim 7, wherein the spring leg guide cylinder and the damper leg damper cylinder have the same diameter, and the spring leg guide rod and the damper leg piston rod have the same diameter.

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