WO2018105683A1 - Front forks - Google Patents

Front forks Download PDF

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Publication number
WO2018105683A1
WO2018105683A1 PCT/JP2017/043940 JP2017043940W WO2018105683A1 WO 2018105683 A1 WO2018105683 A1 WO 2018105683A1 JP 2017043940 W JP2017043940 W JP 2017043940W WO 2018105683 A1 WO2018105683 A1 WO 2018105683A1
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WO
WIPO (PCT)
Prior art keywords
coil spring
front fork
leg
spring
cylinder
Prior art date
Application number
PCT/JP2017/043940
Other languages
French (fr)
Japanese (ja)
Inventor
慶彦 宮内
Original Assignee
Kybモーターサイクルサスペンション株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Kybモーターサイクルサスペンション株式会社 filed Critical Kybモーターサイクルサスペンション株式会社
Publication of WO2018105683A1 publication Critical patent/WO2018105683A1/en

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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B62LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62KCYCLES; CYCLE FRAMES; CYCLE STEERING DEVICES; RIDER-OPERATED TERMINAL CONTROLS SPECIALLY ADAPTED FOR CYCLES; CYCLE AXLE SUSPENSIONS; CYCLE SIDE-CARS, FORECARS, OR THE LIKE
    • B62K25/00Axle suspensions
    • B62K25/04Axle suspensions for mounting axles resiliently on cycle frame or fork
    • B62K25/06Axle suspensions for mounting axles resiliently on cycle frame or fork with telescopic fork, e.g. including auxiliary rocking arms
    • B62K25/08Axle suspensions for mounting axles resiliently on cycle frame or fork with telescopic fork, e.g. including auxiliary rocking arms for front wheel
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16FSPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
    • F16F9/00Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium
    • F16F9/32Details
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16FSPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
    • F16F9/00Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium
    • F16F9/32Details
    • F16F9/48Arrangements for providing different damping effects at different parts of the stroke

Definitions

  • the present invention relates to a front fork.
  • a suspension device used for a vehicle includes a spring called a suspension spring, and the body can be elastically supported by the spring.
  • a suspension spring is a multi-stage coil spring, and the spring constant of the suspension spring can be switched during the stroke.
  • a suspension device for suspending a front wheel of a saddle-ride type vehicle called a front fork includes a pair of legs that support the front wheel from both sides.
  • a suspension spring having the stroke dependency described above is used for such a front fork
  • a common multi-stage coil spring is accommodated in each of the pair of legs, and the suspension spring is usually constituted by the pair of multi-stage coil springs. It is.
  • the multi-stage coil spring has, for example, a coarsely wound portion with a large pitch connected in series and a densely wound portion with a small pitch, and has a structure in which two types of coil springs are connected in series. And when the stroke amount to the contraction side of the front fork is increased and the compression amount of the multistage coil spring is increased, one coil spring (for example, the closely wound portion) is in close contact length, and the spring constant of the suspension spring is switched.
  • the combined spring constant of the plurality of coil springs is smaller than the spring constant of the coil spring alone. For this reason, in order to obtain a desired elastic force as the suspension spring, the number of turns of the multi-stage coil spring must be increased, which increases the weight of the suspension spring as a whole and increases the cost.
  • the present invention aims to provide a front fork that can eliminate such problems and reduce the weight of the suspension spring and reduce the cost even if the spring constant of the suspension spring is changed according to the stroke amount. .
  • the front fork includes a suspension spring that includes a first coil spring and a second coil spring, and the first coil spring is accommodated in one of the pair of legs that support the wheel.
  • the second coil spring is accommodated in the other leg, the first coil spring exerts elastic force over the entire stroke, and the second coil spring exerts elastic force in the stroke region on the contraction side from the middle of the stroke. It is characterized by exhibiting.
  • FIG. 1 is a front view showing a front fork according to an embodiment of the present invention.
  • FIG. 2 is an enlarged longitudinal sectional view of a front fork according to an embodiment of the present invention.
  • FIG. 3 is a partially enlarged sectional view showing a part of FIG.
  • FIG. 4 is an enlarged perspective view showing a front fork spacer according to an embodiment of the present invention.
  • FIG. 5 is a diagram showing the characteristic of the elastic force of the suspension spring with respect to the stroke amount of the front fork according to the embodiment of the present invention.
  • 1 and 2 is a suspension device for suspending front wheels in a straddle-type vehicle such as a two-wheeled vehicle or a three-wheeled vehicle.
  • a straddle-type vehicle such as a two-wheeled vehicle or a three-wheeled vehicle.
  • the upper and lower sides of the front fork F attached to the vehicle are simply referred to as “upper” and “lower” unless otherwise specified.
  • the front fork F includes a pair of leg portions L1 and L2 that stand on both sides of the front wheel W, a vehicle body side bracket BU that connects upper ends of the leg portions L1 and L2, and each leg portion L1. , And an axle bracket BL for connecting the lower end of L2 to the axle of the front wheel W, respectively.
  • a steering shaft S is attached to the vehicle body side bracket BU.
  • the steering shaft S is rotatably inserted into the head pipe of the vehicle body frame that is the skeleton of the vehicle body, and rotates by the operation of the handle.
  • the front fork F rotates about the steering shaft S while supporting the front wheel W, so that the direction of the front wheel can be changed by a steering operation.
  • leg portion L1 and L2 play different roles.
  • One leg L1 shown on the right side in FIG. 2 is a spring leg and does not have a damping force generation function.
  • the other leg portion L2 shown on the left side in FIG. 2 is a damper leg and has a damping force generating function.
  • one leg portion that is a spring leg is referred to as a first leg portion L1
  • the other leg portion that is a damper leg is referred to as a second leg portion L2.
  • Both the first leg portion L1 and the second leg portion L2 include a telescopic tube member 1 configured to include an outer tube 10 and an inner tube 11 that enters and exits the outer tube 10.
  • the tube member 1 is set upside down, and the outer tube 10 is a vehicle body side tube and the inner tube 11 is a wheel side tube.
  • the outer tube 10 is fixed to the vehicle body side bracket BU by welding, and the inner tube 11 is fixed to the axle bracket BL by screwing.
  • the axle bracket BL has a bottomed cylindrical socket portion bs, and the lower end portion of the inner tube 11 is screwed to the inner periphery of the cylindrical portion b1 of the socket portion bs.
  • a cap 12 is attached to the inner periphery of the upper end of each outer tube 10, and the upper end opening (vehicle body side opening) of each tube member 1 is closed by the cap 12.
  • the lower end opening (wheel side opening) of each tube member 1 is closed by the axle bracket BL. That is, in the present embodiment, the axle bracket BL also functions as a cap member (bottom cap) that closes the wheel side opening of the tube member 1.
  • each outer tube 10 On the inner periphery of the lower end portion of each outer tube 10, a bush 13, a oil seal 14, and a dust seal 15 that are in sliding contact with the outer periphery of the inner tube 11 are mounted in this order from the upper side. For this reason, the inside of the outer tube 10 can be smoothly slid in a state where the inner tube 11 is supported by the bush 13. Further, the oil seal 14 and the dust seal 15 can prevent the liquid and gas from leaking out from between the overlapping portions of the outer tube 10 and the inner tube 11.
  • a liquid injection hole b3 that is closed by the plug member 16 is formed in the bottom b2 of the socket bs of the axle bracket BL.
  • the plug member 16 is detachable. When the plug member 16 is removed, the liquid can be supplied into the tube member 1 from the liquid injection hole b3.
  • the outer tube 10 is provided with a support portion 10 a that has an inner diameter substantially equal to the inner diameter of the bush 13 and is in sliding contact with the outer periphery of the inner tube 11. That is, in the present embodiment, the inner periphery of the support portion 10 a of the outer tube 10 and the outer periphery of the inner tube 11 are in direct sliding contact, and the inner tube 11 can be slidably supported by the support portion 10 a and the bush 13.
  • the configuration for supporting the inner tube 11 so as to be slidable is not limited to the above.
  • another bush may be provided on the upper side of the bush 13, and the outer tube 10 may support the inner tube 11 slidably through the pair of upper and lower bushes.
  • the upper bush to be added may be attached to the outer periphery of the inner tube 11 and slidably contacted to the inner periphery of the outer tube 10, or may be attached to the inner periphery of the outer tube 10 and slidably contacted to the outer periphery of the inner tube 11. It may be allowed.
  • the first leg portion L1 and the second leg portion L2 accommodate coil springs having different lengths that function as the suspension spring 2 in cooperation with each other.
  • the long spring accommodated in the first leg L1 is the first coil spring 20
  • the short spring accommodated in the second leg L2 is the second coil spring 21.
  • the first coil spring 20 and the second coil spring 21 exert an elastic force when compressed.
  • the elastic force increases as the amount of compression increases, and acts to extend the front fork F and push up the vehicle body. Therefore, the vehicle body can be elastically supported by the suspension spring 2.
  • first leg portion L1 which is a spring leg has an upper end fixed to the cap 12 and a lower side inserted into the inner tube 11 and a lower end of the rod 3 attached to the inner tube 11.
  • a movable spring receiver 30 that moves in the axial direction
  • an annular fixed spring receiver 40 that is fixed to the upper end of the inner tube 11 and through which the rod 3 passes
  • a movable spring receiver 30 and a fixed spring receiver 40 and an extension spring 4 interposed therebetween.
  • the first coil spring 20 is interposed between the bottom b2 of the axle bracket BL and the movable spring receiver 30.
  • the upper and lower ends of the rod 3 are respectively formed with screw grooves, and the cap 12 and the movable spring receiver 30 are connected to the upper and lower outer circumferences of the rod 3 by screwing.
  • the rod 3 is connected to the outer tube 10 via a cap 12, and when the front fork F expands and contracts, the rod 3 enters and exits the inner tube 11, and the movable spring receiver 30 moves up and down in the inner tube 11. Moving.
  • the movable spring receiver 30 has a bottomed cylindrical connecting portion 30a that is screwed onto the outer periphery of the rod 3, and an annular flange portion 30b that protrudes radially outward from the lower end portion of the connecting portion 30a. And the lower end of the extending spring 4 contacts the upper surface of the flange portion 30b, and the upper end of the first coil spring 20 contacts the lower surface of the flange portion 30b.
  • the extension spring 4 is a coil spring, and the upper end of the extension spring 4 is separated from the fixed spring receiver 40 in a normal stroke range. However, when the stroke amount to the extension side of the front fork F becomes larger than a predetermined amount, the upper end of the extension spring 4 abuts against the fixed spring receiver 40. Then, the extending spring 4 is compressed between the fixed spring receiver 40 and the movable spring receiver 30 to exert an elastic force. The elastic force of the extending spring 4 acts in the direction in which the movable fork receiver 30 is pushed down and the front fork F is contracted.
  • the upper end of the first coil spring 20 is supported by the movable spring receiver 30, and the lower end is supported by the bottom b2 of the axle bracket BL.
  • the elastic force of the first coil spring 20 acts to push up the movable spring receiver 30 and extend the front fork F.
  • the upper end and the lower end of the first coil spring 20 are always in contact with the movable spring receiver 30 and the axle bracket BL. For this reason, the first coil spring 20 exerts an elastic force over the entire stroke of the front fork F, and biases the front fork F in the extending direction.
  • the outer diameter of the movable spring receiver 30 is formed smaller than the inner diameter of the inner tube 11, and the inner diameter of the fixed spring receiver 40 is formed larger than the outer diameter of the rod 3. For this reason, the liquid and gas accommodated in the tube member 1 move through a gap formed between the movable spring receiver 30 and the inner tube 11 and a gap formed between the fixed spring receiver 40 and the rod 3. it can.
  • the liquid stored in the tube member 1 can lubricate the sliding surfaces such as the outer periphery of the inner tube 11, the inner periphery of the support portion 10 a of the outer tube 10, and the inner periphery of the bush 13.
  • the movable spring receiver 30 or the fixed spring receiver 40 may be provided with a through hole or a notch to allow movement of liquid and gas.
  • the second leg portion L2 that is a damper leg includes a cylinder 5 disposed inside the inner tube 11, a piston 60 that is slidably inserted into the cylinder 5, and a lower end connected to the piston 60. And a rod 6 whose upper end protrudes outside the cylinder 5 and an annular rod guide 50 which is attached to the upper end opening of the cylinder 5 and supports the rod 6 slidably.
  • the spacer 7 is provided inside the cylinder 5 and below the piston 60, and the second coil spring 21 is provided below the spacer 7.
  • the cylinder 5 is disposed along the axial direction inside the inner tube 11.
  • the lower end of the cylinder 5 is abutted against the bottom b2 of the axle bracket BL and the upper end of the inner tube 11 is crimped inward with the rod guide 50 fitted to the upper end of the cylinder 5,
  • the cylinder 5 and the rod guide 50 are fixed to the inner tube 11.
  • the inside of the cylinder 5 is divided into two chambers by a piston 60. Of these two rooms, assuming that one of the chambers that contracts when the front fork F extends is the expansion side chamber R1, and the other chamber that contracts when the front fork F contracts is the compression side chamber R2, in this embodiment, the expansion side chamber R1. Is arranged on the upper side, and the pressure side chamber R2 is arranged on the lower side.
  • the extension side chamber R1 and the compression side chamber R2 are filled with liquid such as hydraulic oil.
  • a liquid storage chamber R3 is formed on the outer periphery of the cylinder 5, and the liquid is stored and gas is sealed above the liquid surface to form an air chamber G.
  • the cylinder 5 is formed with an extension side communication hole 5a and a pressure side communication hole 5b communicating with the inside and outside of the cylinder 5.
  • the extension side communication hole 5a and the pressure side communication hole 5b function as a throttle and provide resistance to the flow of the liquid.
  • the extension side communication hole 5a is formed at an upper portion of the cylinder 5 and at a position always lower than the liquid level of the liquid reservoir chamber R3.
  • the pressure side communication hole 5b is formed at a position lower than the extension side communication hole 5a. In the normal stroke range, the piston 60 moves between the expansion side communication hole 5a and the pressure side communication hole 5b.
  • the piston 60 is formed in an annular shape and is fixed to the outer periphery of the lower end of the rod 6.
  • a screw groove is formed in the upper end portion of the rod 6, and the cap 12 is connected to the outer periphery of the upper end portion of the rod 6 by screwing.
  • the rod 6 is connected to the outer tube 10 via the cap 12, and when the front fork F expands and contracts, the rod 6 enters and exits the cylinder 5 and the piston 60 moves up and down in the cylinder 5.
  • the piston 60 is provided with a communication passage 60a that connects the extension side chamber R1 and the pressure side chamber R2, and a pressure side valve 61 that opens and closes the communication passage 60a.
  • the pressure side valve 61 is an annular plate-like leaf valve. The outer peripheral side is allowed to bend. The outer peripheral portion of the pressure side valve 61 can be attached to and detached from a valve seat 60b that surrounds the upper end opening of the communication passage 60a.
  • the pressure in the extension side chamber R1 acts in a direction to close the pressure side valve 61 by pressing the outer periphery of the pressure side valve 61 against the valve seat 60b.
  • the pressure in the pressure side chamber R2 acts on the pressure side valve 61 through the communication passage 60a, and acts in a direction to open the pressure side valve 61 by separating the outer periphery of the pressure side valve 61 from the valve seat 60b.
  • the pressure side valve 61 is a check valve, and when the pressure in the pressure side chamber R2 exceeds the pressure in the expansion side chamber R1, the outer periphery of the pressure side valve 61 moves away from the valve seat 60b and quickly passes through the communication passage 60a. Open.
  • a notch is formed in the valve seat 60b on which the pressure side valve 61 is seated.
  • the orifice 62 is formed by the notch. Therefore, even when the pressure side valve 61 is closed and the outer peripheral portion of the pressure side valve 61 is seated on the valve seat 60b, the expansion side chamber R1 and the pressure side chamber R2 are communicated with each other through the orifice 62.
  • the configuration of the pressure side valve 61 can be changed as appropriate.
  • the pressure side valve 61 may be a valve other than a leaf valve such as a poppet valve.
  • the method for forming the orifice 62 is not limited to the above, and can be changed as appropriate.
  • a notch may be formed in the outer peripheral portion of the leaf valve, and an orifice may be formed by the notch.
  • the rod guide 50 is connected to the inner periphery of the upper end portion of the cylinder 5 and the outer side of the fitting portion 50a. And an annular large outer diameter portion 50b larger than the outer diameter.
  • An annular step 50c is formed on the outer periphery of the rod guide 50 at the boundary between the fitting portion 50a and the large outer diameter portion 50b, and the upper end of the cylinder 5 is abutted against the step 50c.
  • a through hole 50d is formed in the large outer diameter portion 50b.
  • a space formed between the inner tube 11 and the cylinder 5 on the outer periphery of the cylinder 5 and a space formed between the rod 6 protruding outside the cylinder 5 and the outer tube 10 are communicated, Liquid and gas can freely move between these. That is, the liquid reservoir chamber R3 is prevented from being partitioned by the rod guide 50 by the through hole 50d.
  • the position of the liquid level in the liquid reservoir R3 can be lowered to the outer periphery of the cylinder 5 to secure the volume of the air chamber G, and the pressure in the air chamber G can be prevented from becoming excessive when the front fork F contracts.
  • the load on the seal can be reduced.
  • the rod 6 enters the cylinder 5 and the piston 60 moves downward in the cylinder 5. Then, the liquid in the pressure side chamber R2 to be reduced opens the pressure side valve 61 and moves to the extension side chamber R1 through the communication path 60a.
  • the pressure side valve 61 is a check valve, when the front fork F is contracted, the pressures in the extension side chamber R1 and the pressure side chamber R2 are substantially equal.
  • the liquid for the volume of the rod that enters the cylinder 5 becomes surplus in the cylinder 5, so that the surplus liquid passes through the pressure side communication hole 5b and passes from the pressure side chamber R2 to the liquid reservoir chamber. Move to R3. Then, since resistance is given to the flow of the liquid by the pressure side communication hole 5b, the pressure in the cylinder 5 rises, and a pressure side damping force that prevents the contraction operation of the front fork F is generated.
  • the spacer 7 and the second coil spring 21 provided on the lower side of the piston 60 are disposed in the compression side chamber R2.
  • the spacer 7 includes a columnar main body portion 7 a and a convex portion 7 b that protrudes downward from the lower end of the main body portion 7 a and into which the second coil spring 21 is fitted.
  • the cross section of the main body portion 7a is substantially constant in the axial direction and has a substantially cross shape.
  • the main body portion 7a has a shape in which four protrusions 7d extend radially outward from the center portion 7c in the radial direction. Assuming that the recesses formed between the adjacent protrusions 7d and 7d are cutouts 7e, the cutouts 7e are continuously formed from one end to the other end in the axial direction of the main body portion 7a.
  • the outer diameter of the main body portion 7a is smaller than the inner diameter of the cylinder 5 and larger than the outer diameter of the convex portion 7b. .
  • the spacer 7 can move up and down in the cylinder 5 while being stacked on the second coil spring 21.
  • the liquid in the pressure side chamber R2 can freely move in the gap formed between the protrusion 7d and the cylinder 5 and the gap formed between the spacer 7 and the cylinder 5 by the notch 7e. Therefore, the pressure side chamber R2 is not partitioned by the spacer 7 and the pressure side communication hole 5b is not blocked by the spacer 7. Even if the pressure side chamber R2 has the spacer 7, the second leg L2 functions as a damper. Can exert damping force.
  • the second coil spring 21 provided on the lower side of the spacer 7 has its upper end abutted against the lower surface of the main body portion 7a with its upper end fitted to the convex portion 7b.
  • the lower end is supported by the bottom b2 of the axle bracket BL.
  • the upper end of the spacer 7 is separated from the lower end of the rod 6, and the elastic force of the second coil spring 21 is not transmitted to the rod 6.
  • the second coil spring 21 is compressed between the rod 6 and the axle bracket BL, and the amount of compression depends on the compression amount. Demonstrate the elastic force.
  • the elastic force of the second coil spring 21 acts in the direction of pushing up the rod 6 via the spacer 7.
  • the second coil spring 21 functions only in a partial stroke region on the contraction side from the middle of the stroke, and urges the front fork F in the extending direction.
  • the lower end of the rod 6 projects downward from the piston 60, and the spacer 7 strikes the portion.
  • the spacer 7 may be abutted against the lower surface of the piston 60.
  • the inner tube 11 of the first leg L1 and the second leg L2 enters and exits the outer tube 10 and the front fork F expands and contracts.
  • the second leg portion L2 which is a damper leg functions as a damper and exhibits a damping force
  • the suspension spring 2 configured to include the first coil spring 20 and the second coil spring 21 is compressed. Delivers the corresponding elastic force.
  • the second coil spring 21 does not function in the stroke region X on the extension side of the stroke position P, and the stroke It functions in the stroke area Y on the contraction side with respect to the position P. Accordingly, in the stroke region X where the second coil spring 21 does not function, only the first coil spring 20 substantially functions as the suspension spring 2. For this reason, the spring constant of the suspension spring 2 in the stroke region X is equal to the spring constant of the first coil spring 20.
  • both the first coil spring 20 and the second coil spring 21 function as the suspension spring 2.
  • the spring constant of the suspension spring 2 in the stroke region Y is a combined spring constant of the spring constant of the first coil spring 20 and the spring constant of the second coil spring 21. Then, the spring constant of the suspension spring 2 in the stroke region Y becomes larger than the spring constant of the suspension spring 2 in the stroke region X.
  • the spring constant of the suspension spring 2 is increased in the stroke region Y where the stroke amount toward the contraction side is larger than the predetermined (stroke position P), and the elastic force of the suspension spring 2 with respect to the stroke amount. Becomes larger.
  • the suspension spring 2 has a stroke dependency that switches to a large spring constant when the contraction amount becomes larger than a predetermined amount.
  • the elastic force of the suspension spring 2 is reduced in the stroke region X where the contraction amount of the front fork F is small, and the elastic force of the suspension spring 2 is increased in the stroke region Y where the contraction amount is large.
  • the elastic force of the suspension spring 2 when the loaded load is small can be reduced to improve the riding comfort of the vehicle.
  • the elastic force of the suspension spring 2 when the loaded load becomes large due to the influence of passengers, cargo, etc. can be increased, and the frequency with which the front fork F is bottomed (becomes the most compressed state) can be reduced. That is, in the front fork F, the spring constant of the suspension spring 2 can be switched according to the stroke amount so as to be a spring constant according to the load, so that the riding comfort of the vehicle can be improved.
  • the front fork F when the front fork F extends beyond the normal stroke range, the front fork F has an elastic force of the extending spring 4 of the first leg L1 and a large extension side damping force of the second leg L2.
  • the extension speed can be reduced. Therefore, the impact when the front fork F is fully extended can be alleviated, and the riding comfort of the vehicle can be further improved.
  • the second coil spring 21 is compressed via the spacer 7. For this reason, for example, if the spacer 7 is changed to a spacer having a different length, the stroke position P for switching the spring constant of the suspension spring 2 can be changed. That is, since the stroke position P can be changed without changing the second coil spring 21, the stroke position P can be easily adjusted.
  • the spacer 7 is disposed between the piston 60 and the second coil spring 21.
  • the spacer 7 can be used as a spring receiver, and there is no need to provide a spring receiver on the piston 60 or the rod 6.
  • the spacer 7 is provided so as to be separable from the piston 60 and the rod 6. For this reason, replacement of the spacer 7 is easy.
  • the spacer 7 has a columnar main body 7a and a convex portion 7b that is connected to the lower end (one end in the axial direction) of the main body 7a and has an outer diameter smaller than the outer diameter of the main body 7a.
  • the 2nd coil spring 21 fits to the outer periphery of the convex part 7b. For this reason, it can prevent that the spacer 7 and the 2nd coil spring 21 shift
  • the outer diameter of the main body portion 7a is smaller than the inner diameter of the cylinder 5, and a notch 7e is formed on the outer periphery of the main body portion 7a so as to continue from one end to the other end in the axial direction. For this reason, even if the spacer 7 is provided in the pressure side chamber R2, the pressure side chamber R2 is not partitioned by the spacer 7. In addition, the spacer 7 does not hinder the flow of the liquid flowing back and forth between the expansion side chamber R1 and the pressure side chamber R2, and the flow of the liquid flowing back and forth between the pressure side chamber R2 and the liquid storage chamber R3, and generates a damping force. Will not hinder.
  • the spacer 7 when the spacer 7 is formed of a synthetic resin, the spacer can be reduced in weight and the design freedom of the shape is high. Therefore, as described above, it is easy to provide the convex portion 7b or the notch 7e.
  • the configuration of the spacer 7 is not limited to the above, and the shape, material, and arrangement can be changed as appropriate.
  • the spacer may be connected to the piston 60 or the rod 6 to integrate them, or may be provided below the second coil spring 21. Further, if the stroke position P can be set arbitrarily, the spacer may be eliminated.
  • the second leg (the other leg) L2 is a damper leg that functions as a damper, and exerts a damping force by imparting resistance to the flow of liquid contained therein.
  • the monopod (one leg) L1 does not have such a function.
  • the longer first coil spring 20 is accommodated in the first leg L1
  • the shorter second coil spring 21 is the first coil spring 21. Housed in the bipod L2.
  • the long first coil spring 20 is accommodated in the first leg L1 that does not accommodate components (cylinder 5, rod 6, piston 60, etc.) necessary for generating the damping force. For this reason, even if the length of the 1st coil spring 20 is long, it can suppress that the 1st leg part L1 is bulky in an axial direction.
  • the second leg portion L2 since the length of the second coil spring 21 accommodated in the second leg portion L2 is shorter than that of the first coil spring 20, the second leg portion L2 that accommodates the parts necessary for generating the damping force is second. Even if the two-coil spring 21 is accommodated, the second leg L2 can be prevented from being bulky in the axial direction.
  • the storage length of the front fork F can be shortened to improve the mountability.
  • the length of the leg portion cannot often be increased. For this reason, it is effective to employ the above configuration particularly in such a form of front fork.
  • the second leg portion (the other leg portion) L2 which is a damper leg includes a telescopic tube member 1 having an outer tube (vehicle body side tube) 10 and an inner tube (wheel side tube) 11, and an inner tube 11.
  • a telescopic tube member 1 having an outer tube (vehicle body side tube) 10 and an inner tube (wheel side tube) 11, and an inner tube 11.
  • are connected to the outer tube 10 are connected to the cylinder 5, are slidably inserted into the cylinder 5, are slidably inserted into the cylinder 5, and are divided into an extension side chamber R 1 and a pressure side chamber R 2.
  • a rod 6 whose tip (one end) is connected to the piston 60.
  • a liquid is stored between the tube member 1 and the cylinder 5 to form a liquid storage chamber R3.
  • the cylinder 5 resists the flow of liquid from the pressure side chamber R2 to the liquid storage chamber R3.
  • a pressure side communication hole 5b is formed.
  • the compression side communication hole 5b is a compression side damping force generation element, so the configuration of the compression side damping force generation element is very simple and the manufacture of the front fork F can be facilitated. Moreover, since the pressure side communication hole 5b is formed in the side part of the cylinder 5, when the 2nd coil spring 21 is arrange
  • the pressure-side damping force generating element is a valve such as a leaf valve, and when the valve gives resistance to the flow of liquid from the pressure-side chamber R2 to the liquid reservoir chamber R3, it is fixed to the lower end portion of the cylinder 5.
  • the valve is attached to the partition member, and resistance is given to the flow of the liquid passing through the passage formed in the partition member by the valve.
  • the number of parts of the damper leg is increased and the structure becomes complicated, and the second coil spring 21 must be disposed on the upper side by providing the partition member. Therefore, when the second coil spring 21 is provided in the pressure side chamber of such a damper leg, the damper leg becomes longer in the axial direction, and the front fork may not fit in a predetermined space.
  • the configuration of the second leg L2 which is the damper leg can be simplified. Furthermore, since the lower end of the second coil spring 21 can be directly supported by the axle bracket BL, the support mechanism of the second coil spring 21 can be extremely simplified. Therefore, the structure of the front fork F can be simplified and the cost can be reduced. In addition, since the position of the second coil spring 21 can be lowered, it is possible to prevent the second leg portion L2 from being bulky in the axial direction.
  • the structure of the 1st leg part L1 and the 2nd leg part L2 is not restricted above, and can be changed suitably.
  • the compression-side damping force generating element in the second leg L2 may be changed to a valve such as a leaf valve.
  • the orifice 62 and the extension side communication hole 5a are elements for generating a damping force on the extension side.
  • the structure of the damping force generating element on the extension side is very simple, and the manufacture of the front fork F can be facilitated.
  • the extension side damping force generation element may be only one of the orifice 62 and the extension side communication hole 5a.
  • the extension side damping force generating element may be a valve such as a leaf valve. In this way, the configuration of the damping force generating elements on the extension side and the compression side in the damper leg can be appropriately changed.
  • the inside of the cylinder 5 is communicated with the liquid reservoir chamber L3 via the pressure side communication hole 5b, and the cylinder volume change due to the rod protruding and retracting volume and the cylinder due to the temperature change
  • the volume change of the liquid in 5 can be compensated by the liquid reservoir R3. That is, the liquid reservoir L3 functions as a reservoir liquid reservoir, and the tube member 1 constitutes a reservoir housing.
  • an air chamber that can be expanded and contracted in the cylinder 5 may be defined by a movable partition wall such as a free piston or a bladder, and volume compensation may be performed in the air chamber.
  • the cylinder 5 is eliminated, the piston 60 is slidably contacted with the inner periphery of the inner tube 11, and the inner tube 11 functions as a cylinder. Also good.
  • each tube member 1 is set to the inverted type, the outer tube 10 becomes a vehicle body side tube, and the inner tube 11 becomes a wheel side tube. ing. For this reason, since an axle bracket can be reduced in size compared with the case where an upright tube member in which an outer tube and an axle bracket are integrated is used, a front fork can be formed at a low cost.
  • the tube member 1 may be an upright type. Thus, the structure of the tube member of each leg can be changed as appropriate.
  • first leg portion L1 may be a damper leg that functions as a damper
  • second leg portion L2 may be a spring leg that does not function as a damper
  • the front fork F includes a first leg L1 and a second leg L2 (a pair of legs) that support the front wheel (wheel) W, and a suspension spring 2 that elastically supports the vehicle body.
  • the suspension spring 2 includes a first coil spring 20 that is accommodated in the first leg portion (one leg portion) L1 and exhibits an elastic force over the entire stroke of the front fork F, and a second leg portion (the other leg portion). Part) The second coil spring 21 that is housed in L2 and that exerts an elastic force in the stroke region Y on the contraction side from the middle of the stroke.
  • the stroke region X in which only the first coil spring 20 functions and the stroke region Y in which both the first coil spring 20 and the second coil spring 21 function are formed. It can be changed according to the stroke amount.
  • the 1st coil spring 20 and the 2nd coil spring 21 exhibit force in parallel, two types of coil springs, the 1st coil spring 20 and the 2nd coil spring 21, are used as the suspension spring 2. Even if it is used, the combined spring constant of the two coil springs is larger than the spring constant of the coil spring alone. For this reason, the number of turns of the coil spring as a whole suspension spring can be reduced as compared with a conventional front fork using a multistage coil spring in which two types of coil springs exert a force in series. Therefore, the weight of the suspension spring is reduced, and the cost can be reduced.
  • the front fork F can be reduced in size, and the front fork can be reduced in weight and further reduced in cost.
  • the spring constant of the suspension spring 2 is switched approximately at the center of the entire stroke area of the front fork F.
  • the stroke position P at which the spring constant of the suspension spring 2 is switched can be appropriately changed according to the desired spring characteristic of the suspension spring 2. The change can be made regardless of the configuration and presence of the spacer and the configuration of the pair of legs.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Axle Suspensions And Sidecars For Cycles (AREA)
  • Fluid-Damping Devices (AREA)

Abstract

Front forks (F) comprising: a pair of legs (L1), (L2) that support a wheel; and a suspension spring (2) that elastically supports a vehicle body. The suspension spring (2) has: a first coil spring (20) housed in one leg (L1) and exerting elastic force over the entire stroke range; and a second coil spring (21) housed in the other leg (L2) and exerting elastic force from mid-stroke to the compression-side stroke.

Description

フロントフォークFront fork
 本発明は、フロントフォークに関する。 The present invention relates to a front fork.
 一般的に、車両に利用される懸架装置は、懸架ばねと称されるばねを備え、当該ばねで車体を弾性支持できるようになっている。そして、懸架装置の中には、たとえば、JP2003-97615Aに開示されているように、懸架ばねを多段コイルばねにして、懸架ばねのばね定数をストロークの途中で切り換えられるものがある。 Generally, a suspension device used for a vehicle includes a spring called a suspension spring, and the body can be elastically supported by the spring. In some suspension devices, for example, as disclosed in JP2003-97615A, a suspension spring is a multi-stage coil spring, and the spring constant of the suspension spring can be switched during the stroke.
 また、フロントフォークと称される鞍乗型車両の前輪を懸架する懸架装置は、前輪を両側から支える一対の脚部を備える。このようなフロントフォークに前述のストローク依存性を持つ懸架ばねを利用する場合、一対の脚部に共通の多段コイルばねをそれぞれ収容し、これら一対の多段コイルばねで懸架ばねを構成するのが通常である。 Also, a suspension device for suspending a front wheel of a saddle-ride type vehicle called a front fork includes a pair of legs that support the front wheel from both sides. When such a suspension spring having the stroke dependency described above is used for such a front fork, a common multi-stage coil spring is accommodated in each of the pair of legs, and the suspension spring is usually constituted by the pair of multi-stage coil springs. It is.
 上記多段コイルばねは、例えば、直列に接続されたピッチの大きい粗巻部と、ピッチの小さい密巻部とを有し、二種類のコイルばねが直列に連なる構造となっている。そして、フロントフォークの収縮側へのストローク量が大きくなって多段コイルばねの圧縮量が大きくなると、一方のコイルばね(例えば、密巻部)が密着長となり、懸架ばねのばね定数が切り換わる。 The multi-stage coil spring has, for example, a coarsely wound portion with a large pitch connected in series and a densely wound portion with a small pitch, and has a structure in which two types of coil springs are connected in series. And when the stroke amount to the contraction side of the front fork is increased and the compression amount of the multistage coil spring is increased, one coil spring (for example, the closely wound portion) is in close contact length, and the spring constant of the suspension spring is switched.
 しかし、上記多段コイルばねのように、複数のコイルばねが直列に力を発揮する構造の場合、複数のコイルばねの合成のばね定数は、コイルばね単体でのばね定数よりも小さくなる。このため、懸架ばねとしての所望の弾性力を得るには多段コイルばねの巻数を多くしなければならず、懸架ばね全体としての重量が重くなるとともに、コスト高になる。 However, in the case of a structure in which a plurality of coil springs exert force in series as in the above-described multistage coil spring, the combined spring constant of the plurality of coil springs is smaller than the spring constant of the coil spring alone. For this reason, in order to obtain a desired elastic force as the suspension spring, the number of turns of the multi-stage coil spring must be increased, which increases the weight of the suspension spring as a whole and increases the cost.
 そこで、本発明は、このような不具合を解消し、懸架ばねのばね定数をストローク量に応じて変更しても、懸架ばねの重量を軽量化してコストを低減できるフロントフォークの提供を目的とする。 Therefore, the present invention aims to provide a front fork that can eliminate such problems and reduce the weight of the suspension spring and reduce the cost even if the spring constant of the suspension spring is changed according to the stroke amount. .
 そのため、フロントフォークは、第一コイルばねと第二コイルばねとを有して構成される懸架ばねを備え、車輪を支持する一対の脚部のうちの一方の脚部に第一コイルばねを収容するとともに、他方の脚部に第二コイルばねを収容し、前記第一コイルばねがストローク全域で弾性力を発揮し、前記第二コイルばねがストロークの途中から収縮側のストローク領域で弾性力を発揮することを特徴とする。 Therefore, the front fork includes a suspension spring that includes a first coil spring and a second coil spring, and the first coil spring is accommodated in one of the pair of legs that support the wheel. The second coil spring is accommodated in the other leg, the first coil spring exerts elastic force over the entire stroke, and the second coil spring exerts elastic force in the stroke region on the contraction side from the middle of the stroke. It is characterized by exhibiting.
図1は、本発明の一実施の形態に係るフロントフォークを示す正面図である。FIG. 1 is a front view showing a front fork according to an embodiment of the present invention. 図2は、本発明の一実施の形態に係るフロントフォークの拡大縦断面図である。FIG. 2 is an enlarged longitudinal sectional view of a front fork according to an embodiment of the present invention. 図3は、図2の一部を示した部分拡大断面図である。FIG. 3 is a partially enlarged sectional view showing a part of FIG. 図4は、本発明の一実施の形態に係るフロントフォークのスペーサを拡大して示した斜視図である。FIG. 4 is an enlarged perspective view showing a front fork spacer according to an embodiment of the present invention. 図5は、本発明の一実施の形態に係るフロントフォークのストローク量に対する懸架ばねの弾性力の特性を示した図である。FIG. 5 is a diagram showing the characteristic of the elastic force of the suspension spring with respect to the stroke amount of the front fork according to the embodiment of the present invention.
 以下に本発明の実施の形態について、図面を参照しながら説明する。いくつかの図面を通して付された同じ符号は、同じ部品か対応する部品を示す。 Embodiments of the present invention will be described below with reference to the drawings. The same reference numerals given throughout the several drawings indicate the same or corresponding parts.
 図1,2に示す本発明の一実施の形態に係るフロントフォークFは、二輪車又は三輪車等の鞍乗型車両において、前輪を懸架するための懸架装置である。以下、説明の便宜上、車両に取り付けられた状態でのフロントフォークFの上下を、特別な説明がない限り単に「上」「下」という。 1 and 2 is a suspension device for suspending front wheels in a straddle-type vehicle such as a two-wheeled vehicle or a three-wheeled vehicle. Hereinafter, for convenience of explanation, the upper and lower sides of the front fork F attached to the vehicle are simply referred to as “upper” and “lower” unless otherwise specified.
 図1に示すように、フロントフォークFは、前輪Wの両側に起立する一対の脚部L1,L2と、これら脚部L1,L2の上端部を連結する車体側ブラケットBUと、各脚部L1,L2の下端部を前輪Wの車軸にそれぞれ連結するアクスルブラケットBLとを備える。また、上記車体側ブラケットBUには、ステアリングシャフトSが取り付けられている。 As shown in FIG. 1, the front fork F includes a pair of leg portions L1 and L2 that stand on both sides of the front wheel W, a vehicle body side bracket BU that connects upper ends of the leg portions L1 and L2, and each leg portion L1. , And an axle bracket BL for connecting the lower end of L2 to the axle of the front wheel W, respectively. A steering shaft S is attached to the vehicle body side bracket BU.
 図示しないが、ステアリングシャフトSは、車体の骨格となる車体フレームのヘッドパイプ内に回転自在に挿入されており、ハンドルの操作により回転する。そして、ステアリングシャフトSを回転すると、フロントフォークFが前輪Wを支持しつつステアリングシャフトSを中心に回転するので、ハンドル操作により前輪の向きを変えられる。 Although not shown, the steering shaft S is rotatably inserted into the head pipe of the vehicle body frame that is the skeleton of the vehicle body, and rotates by the operation of the handle. When the steering shaft S is rotated, the front fork F rotates about the steering shaft S while supporting the front wheel W, so that the direction of the front wheel can be changed by a steering operation.
 また、一対の脚部L1,L2は、それぞれ異なる役割を担う。図2中右側に記載の一方の脚部L1はばね脚であり、減衰力発生機能を有していない。これに対し、図2中左側に記載の他方の脚部L2はダンパ脚であり、減衰力発生機能を有する。以下、これらの脚部L1,L2を区別するため、ばね脚である一方の脚部を第一脚部L1とし、ダンパ脚である他方の脚部を第二脚部L2とする。 Also, the pair of leg portions L1 and L2 play different roles. One leg L1 shown on the right side in FIG. 2 is a spring leg and does not have a damping force generation function. On the other hand, the other leg portion L2 shown on the left side in FIG. 2 is a damper leg and has a damping force generating function. Hereinafter, in order to distinguish these leg portions L1 and L2, one leg portion that is a spring leg is referred to as a first leg portion L1, and the other leg portion that is a damper leg is referred to as a second leg portion L2.
 まず、第一脚部L1と第二脚部L2において、共通する構成について説明する。第一脚部L1と第二脚部L2は、ともに、アウターチューブ10と、アウターチューブ10に出入りするインナーチューブ11とを有して構成されるテレスコピック型のチューブ部材1を有する。 First, a common configuration in the first leg L1 and the second leg L2 will be described. Both the first leg portion L1 and the second leg portion L2 include a telescopic tube member 1 configured to include an outer tube 10 and an inner tube 11 that enters and exits the outer tube 10.
 チューブ部材1は、倒立型に設定されており、アウターチューブ10が車体側チューブ、インナーチューブ11が車輪側チューブとなっている。そして、アウターチューブ10が車体側ブラケットBUに溶接により固定され、インナーチューブ11がアクスルブラケットBLに螺合により固定される。より具体的には、アクスルブラケットBLが有底筒状のソケット部bsを有しており、当該ソケット部bsの筒部b1の内周にインナーチューブ11の下端部が螺合されている。 The tube member 1 is set upside down, and the outer tube 10 is a vehicle body side tube and the inner tube 11 is a wheel side tube. The outer tube 10 is fixed to the vehicle body side bracket BU by welding, and the inner tube 11 is fixed to the axle bracket BL by screwing. More specifically, the axle bracket BL has a bottomed cylindrical socket portion bs, and the lower end portion of the inner tube 11 is screwed to the inner periphery of the cylindrical portion b1 of the socket portion bs.
 このため、車両が凹凸のある路面を走行する等して前輪W(図1)が上下に振動すると、アウターチューブ10にインナーチューブ11が出入りして第一脚部L1と第二脚部L2が伸縮し、フロントフォークFが伸縮する。 For this reason, when the front wheel W (FIG. 1) vibrates up and down, for example, when the vehicle travels on an uneven road surface, the inner tube 11 enters and exits the outer tube 10, and the first leg portion L1 and the second leg portion L2 move. The front fork F expands and contracts.
 各アウターチューブ10の上端部内周には、キャップ12が装着されており、当該キャップ12で各チューブ部材1の上端開口(車体側開口)が塞がれる。その一方、各チューブ部材1の下端開口(車輪側開口)は、上記アクスルブラケットBLで塞がれる。つまり、本実施の形態において、アクスルブラケットBLは、チューブ部材1の車輪側開口を塞ぐキャップ部材(ボトムキャップ)としても機能する。 A cap 12 is attached to the inner periphery of the upper end of each outer tube 10, and the upper end opening (vehicle body side opening) of each tube member 1 is closed by the cap 12. On the other hand, the lower end opening (wheel side opening) of each tube member 1 is closed by the axle bracket BL. That is, in the present embodiment, the axle bracket BL also functions as a cap member (bottom cap) that closes the wheel side opening of the tube member 1.
 また、各アウターチューブ10の下端部内周には、インナーチューブ11の外周に摺接するブッシュ13、オイルシール14、及びダストシール15が上側からこの順に装着されている。このため、インナーチューブ11がブッシュ13で支えられた状態でアウターチューブ10内を円滑に摺動できる。また、オイルシール14とダストシール15でアウターチューブ10とインナーチューブ11の重複部の間から液体と気体が外部へ漏れ出るのを防止できる。 Further, on the inner periphery of the lower end portion of each outer tube 10, a bush 13, a oil seal 14, and a dust seal 15 that are in sliding contact with the outer periphery of the inner tube 11 are mounted in this order from the upper side. For this reason, the inside of the outer tube 10 can be smoothly slid in a state where the inner tube 11 is supported by the bush 13. Further, the oil seal 14 and the dust seal 15 can prevent the liquid and gas from leaking out from between the overlapping portions of the outer tube 10 and the inner tube 11.
 本実施の形態において、アクスルブラケットBLのソケット部bsにおける底部b2には、栓部材16で塞がれる注液孔b3が形成されている。栓部材16は、着脱可能となっており、当該栓部材16を外すと注液孔b3からチューブ部材1内へ液体を供給できる。 In the present embodiment, a liquid injection hole b3 that is closed by the plug member 16 is formed in the bottom b2 of the socket bs of the axle bracket BL. The plug member 16 is detachable. When the plug member 16 is removed, the liquid can be supplied into the tube member 1 from the liquid injection hole b3.
 また、本実施の形態において、アウターチューブ10には、内径が上記ブッシュ13の内径と略等しく、インナーチューブ11の外周に摺接する支持部10aが設けられている。つまり、本実施の形態では、アウターチューブ10の支持部10aの内周とインナーチューブ11の外周が直接摺接し、支持部10aとブッシュ13でインナーチューブ11を摺動自在に支持できる。 Further, in the present embodiment, the outer tube 10 is provided with a support portion 10 a that has an inner diameter substantially equal to the inner diameter of the bush 13 and is in sliding contact with the outer periphery of the inner tube 11. That is, in the present embodiment, the inner periphery of the support portion 10 a of the outer tube 10 and the outer periphery of the inner tube 11 are in direct sliding contact, and the inner tube 11 can be slidably supported by the support portion 10 a and the bush 13.
 なお、インナーチューブ11を摺動可能に支持するための構成は、上記の限りではない。具体的には、ブッシュ13の上側にもう一つブッシュを設け、アウターチューブ10がこれら上下一対のブッシュを介してインナーチューブ11を摺動自在に支持するとしてもよい。この場合、追加する上側のブッシュをインナーチューブ11の外周に装着してアウターチューブ10の内周に摺接させるとしてもよく、アウターチューブ10の内周に装着してインナーチューブ11の外周に摺接させるとしてもよい。 The configuration for supporting the inner tube 11 so as to be slidable is not limited to the above. Specifically, another bush may be provided on the upper side of the bush 13, and the outer tube 10 may support the inner tube 11 slidably through the pair of upper and lower bushes. In this case, the upper bush to be added may be attached to the outer periphery of the inner tube 11 and slidably contacted to the inner periphery of the outer tube 10, or may be attached to the inner periphery of the outer tube 10 and slidably contacted to the outer periphery of the inner tube 11. It may be allowed.
 次に、第一脚部L1と第二脚部L2とで異なる構成について説明する。これら第一脚部L1と第二脚部L2には、協働して懸架ばね2として機能する長さの異なるコイルばねがそれぞれ収容されている。これらコイルばねのうち、第一脚部L1に収容される全長の長いばねが第一コイルばね20、第二脚部L2に収容される短いばねが第二コイルばね21である。 Next, different configurations of the first leg L1 and the second leg L2 will be described. The first leg portion L1 and the second leg portion L2 accommodate coil springs having different lengths that function as the suspension spring 2 in cooperation with each other. Among these coil springs, the long spring accommodated in the first leg L1 is the first coil spring 20, and the short spring accommodated in the second leg L2 is the second coil spring 21.
 これら第一コイルばね20と第二コイルばね21は、圧縮されると弾性力を発揮する。当該弾性力は、圧縮量が大きくなるほど大きくなり、フロントフォークFを伸長させて車体を押し上げる方向へ作用する。よって、懸架ばね2で車体を弾性支持できる。 The first coil spring 20 and the second coil spring 21 exert an elastic force when compressed. The elastic force increases as the amount of compression increases, and acts to extend the front fork F and push up the vehicle body. Therefore, the vehicle body can be elastically supported by the suspension spring 2.
 また、ばね脚である第一脚部L1は、上端部がキャップ12に固定されるとともに下側がインナーチューブ11の内側に挿入されるロッド3と、ロッド3の下端部に装着されてインナーチューブ11内を軸方向に移動する可動ばね受け30と、インナーチューブ11の上端部に固定されて、中心部をロッド3が貫通する環状の固定ばね受け40と、可動ばね受け30と固定ばね受け40との間に介装される伸切ばね4とを備える。そして、アクスルブラケットBLの底部b2と可動ばね受け30との間に第一コイルばね20が介装されている。 Further, the first leg portion L1 which is a spring leg has an upper end fixed to the cap 12 and a lower side inserted into the inner tube 11 and a lower end of the rod 3 attached to the inner tube 11. A movable spring receiver 30 that moves in the axial direction, an annular fixed spring receiver 40 that is fixed to the upper end of the inner tube 11 and through which the rod 3 passes, and a movable spring receiver 30 and a fixed spring receiver 40. And an extension spring 4 interposed therebetween. The first coil spring 20 is interposed between the bottom b2 of the axle bracket BL and the movable spring receiver 30.
 上記ロッド3の上端部と下端部には、それぞれ螺子溝が形成されており、ロッド3の上下外周にキャップ12と可動ばね受け30がそれぞれ螺合により連結されている。そして、ロッド3は、キャップ12を介してアウターチューブ10に連結されており、フロントフォークFが伸縮すると、ロッド3がインナーチューブ11に出入りして、可動ばね受け30がインナーチューブ11内を上下に移動する。 The upper and lower ends of the rod 3 are respectively formed with screw grooves, and the cap 12 and the movable spring receiver 30 are connected to the upper and lower outer circumferences of the rod 3 by screwing. The rod 3 is connected to the outer tube 10 via a cap 12, and when the front fork F expands and contracts, the rod 3 enters and exits the inner tube 11, and the movable spring receiver 30 moves up and down in the inner tube 11. Moving.
 可動ばね受け30は、ロッド3の外周に螺合する有底筒状の連結部30aと、この連結部30aの下端部から径方向外側へ突出する環状のフランジ部30bとを有する。そして、フランジ部30bの上面に伸切ばね4の下端が当接し、フランジ部30bの下面に第一コイルばね20の上端が当接する。 The movable spring receiver 30 has a bottomed cylindrical connecting portion 30a that is screwed onto the outer periphery of the rod 3, and an annular flange portion 30b that protrudes radially outward from the lower end portion of the connecting portion 30a. And the lower end of the extending spring 4 contacts the upper surface of the flange portion 30b, and the upper end of the first coil spring 20 contacts the lower surface of the flange portion 30b.
 伸切ばね4はコイルばねであり、通常のストローク範囲では、伸切ばね4の上端が固定ばね受け40から離れている。しかし、フロントフォークFの伸長側へのストローク量が所定よりも大きくなると、伸切ばね4の上端が固定ばね受け40に突き当たる。すると、固定ばね受け40と可動ばね受け30との間で伸切ばね4が圧縮されて弾性力を発揮する。当該伸切ばね4の弾性力は、可動ばね受け30を押し下げて、フロントフォークFを収縮させる方向に作用する。 The extension spring 4 is a coil spring, and the upper end of the extension spring 4 is separated from the fixed spring receiver 40 in a normal stroke range. However, when the stroke amount to the extension side of the front fork F becomes larger than a predetermined amount, the upper end of the extension spring 4 abuts against the fixed spring receiver 40. Then, the extending spring 4 is compressed between the fixed spring receiver 40 and the movable spring receiver 30 to exert an elastic force. The elastic force of the extending spring 4 acts in the direction in which the movable fork receiver 30 is pushed down and the front fork F is contracted.
 その一方、第一コイルばね20は、その上端が可動ばね受け30で支持されるとともに、下端がアクスルブラケットBLの底部b2で支持される。当該第一コイルばね20の弾性力は、可動ばね受け30を押し上げて、フロントフォークFを伸長させる方向に作用する。第一コイルばね20の上端と下端は、常に可動ばね受け30とアクスルブラケットBLに当接する。このため、第一コイルばね20は、フロントフォークFのストローク全域で弾性力を発揮して、フロントフォークFを伸長方向へ附勢する。 On the other hand, the upper end of the first coil spring 20 is supported by the movable spring receiver 30, and the lower end is supported by the bottom b2 of the axle bracket BL. The elastic force of the first coil spring 20 acts to push up the movable spring receiver 30 and extend the front fork F. The upper end and the lower end of the first coil spring 20 are always in contact with the movable spring receiver 30 and the axle bracket BL. For this reason, the first coil spring 20 exerts an elastic force over the entire stroke of the front fork F, and biases the front fork F in the extending direction.
 また、可動ばね受け30の外径がインナーチューブ11の内径よりも小さく形成されるとともに、固定ばね受け40の内径がロッド3の外径よりも大きく形成されている。このため、チューブ部材1の内部に収容される液体及び気体は、可動ばね受け30とインナーチューブ11との間にできる隙間と、固定ばね受け40とロッド3との間にできる隙間を通って移動できる。 Further, the outer diameter of the movable spring receiver 30 is formed smaller than the inner diameter of the inner tube 11, and the inner diameter of the fixed spring receiver 40 is formed larger than the outer diameter of the rod 3. For this reason, the liquid and gas accommodated in the tube member 1 move through a gap formed between the movable spring receiver 30 and the inner tube 11 and a gap formed between the fixed spring receiver 40 and the rod 3. it can.
 よって、チューブ部材1の内部に収容される液体でインナーチューブ11の外周、アウターチューブ10の支持部10aの内周、及びブッシュ13の内周等の摺動面を潤滑できる。なお、可動ばね受け30又は固定ばね受け40に貫通孔又は切欠きを設け、これらで液体及び気体の移動を許容するようにしてもよい。 Therefore, the liquid stored in the tube member 1 can lubricate the sliding surfaces such as the outer periphery of the inner tube 11, the inner periphery of the support portion 10 a of the outer tube 10, and the inner periphery of the bush 13. In addition, the movable spring receiver 30 or the fixed spring receiver 40 may be provided with a through hole or a notch to allow movement of liquid and gas.
 つづいて、ダンパ脚である第二脚部L2は、インナーチューブ11の内側に配置されるシリンダ5と、このシリンダ5内に摺動自在に挿入されるピストン60と、下端がピストン60に連結されて上端がシリンダ5外へ突出するロッド6と、シリンダ5の上端開口部に取り付けられて、ロッド6を摺動自在に軸支する環状のロッドガイド50とを備える。そして、シリンダ5の内側であってピストン60の下側にスペーサ7が設けられ、当該スペーサ7の下側に第二コイルばね21が設けられている。 Subsequently, the second leg portion L2 that is a damper leg includes a cylinder 5 disposed inside the inner tube 11, a piston 60 that is slidably inserted into the cylinder 5, and a lower end connected to the piston 60. And a rod 6 whose upper end protrudes outside the cylinder 5 and an annular rod guide 50 which is attached to the upper end opening of the cylinder 5 and supports the rod 6 slidably. The spacer 7 is provided inside the cylinder 5 and below the piston 60, and the second coil spring 21 is provided below the spacer 7.
 シリンダ5は、インナーチューブ11の内側にその軸方向に沿って配置される。そして、本実施の形態では、シリンダ5の下端をアクスルブラケットBLの底部b2に突き当てるとともに、ロッドガイド50をシリンダ5の上端に嵌合した状態でインナーチューブ11の上端を内側に加締めると、シリンダ5及びロッドガイド50がインナーチューブ11に固定される。 The cylinder 5 is disposed along the axial direction inside the inner tube 11. In the present embodiment, when the lower end of the cylinder 5 is abutted against the bottom b2 of the axle bracket BL and the upper end of the inner tube 11 is crimped inward with the rod guide 50 fitted to the upper end of the cylinder 5, The cylinder 5 and the rod guide 50 are fixed to the inner tube 11.
 シリンダ5の内側は、ピストン60で二つの部屋に仕切られている。これら二つの部屋のうち、フロントフォークFの伸長時に縮小する一方の部屋を伸側室R1、フロントフォークFの収縮時に縮小する他方の部屋を圧側室R2とすると、本実施の形態では、伸側室R1が上側に、圧側室R2が下側に配置される。これら伸側室R1と圧側室R2には、作動油等の液体がそれぞれ充填されている。 The inside of the cylinder 5 is divided into two chambers by a piston 60. Of these two rooms, assuming that one of the chambers that contracts when the front fork F extends is the expansion side chamber R1, and the other chamber that contracts when the front fork F contracts is the compression side chamber R2, in this embodiment, the expansion side chamber R1. Is arranged on the upper side, and the pressure side chamber R2 is arranged on the lower side. The extension side chamber R1 and the compression side chamber R2 are filled with liquid such as hydraulic oil.
 その一方、シリンダ5の外周には、液溜室R3が形成されており、液体が貯留されるとともにその液面の上方に気体が封入されて気室Gが形成されている。 On the other hand, a liquid storage chamber R3 is formed on the outer periphery of the cylinder 5, and the liquid is stored and gas is sealed above the liquid surface to form an air chamber G.
 また、シリンダ5には、シリンダ5内外を連通する伸側連通孔5aと圧側連通孔5bが形成されている。伸側連通孔5aと圧側連通孔5bは、絞りとして機能し、液体の流れに抵抗を与える。伸側連通孔5aは、シリンダ5の上部であって、液溜室R3の液面よりも常に低くなる位置に形成されている。また、圧側連通孔5bは、伸側連通孔5aよりもさらに低い位置に形成されている。そして、通常のストローク範囲では、ピストン60が伸側連通孔5aと圧側連通孔5bの間を移動するようになっている。 Further, the cylinder 5 is formed with an extension side communication hole 5a and a pressure side communication hole 5b communicating with the inside and outside of the cylinder 5. The extension side communication hole 5a and the pressure side communication hole 5b function as a throttle and provide resistance to the flow of the liquid. The extension side communication hole 5a is formed at an upper portion of the cylinder 5 and at a position always lower than the liquid level of the liquid reservoir chamber R3. The pressure side communication hole 5b is formed at a position lower than the extension side communication hole 5a. In the normal stroke range, the piston 60 moves between the expansion side communication hole 5a and the pressure side communication hole 5b.
 ピストン60は、環状に形成されており、ロッド6の下端部外周に固定されている。このロッド6の上端部には、螺子溝が形成されており、ロッド6の上端部外周にキャップ12が螺合により連結される。そして、ロッド6は、当該キャップ12を介してアウターチューブ10に連結されており、フロントフォークFが伸縮すると、ロッド6がシリンダ5に出入りしてピストン60がシリンダ5内を上下に移動する。 The piston 60 is formed in an annular shape and is fixed to the outer periphery of the lower end of the rod 6. A screw groove is formed in the upper end portion of the rod 6, and the cap 12 is connected to the outer periphery of the upper end portion of the rod 6 by screwing. The rod 6 is connected to the outer tube 10 via the cap 12, and when the front fork F expands and contracts, the rod 6 enters and exits the cylinder 5 and the piston 60 moves up and down in the cylinder 5.
 ピストン60には、伸側室R1と圧側室R2とを連通する連通路60aが形成されるとともに、連通路60aを開閉する圧側バルブ61が装着されている。図3に示すように、本実施の形態において圧側バルブ61は環板状のリーフバルブであり、ピストン60の上側に積層された状態で、内周部がピストン60とともにロッド6の外周に固定され、外周側の撓みが許容されている。当該圧側バルブ61の外周部は、連通路60aの上端開口を囲う弁座60bに離着座可能となっている。 The piston 60 is provided with a communication passage 60a that connects the extension side chamber R1 and the pressure side chamber R2, and a pressure side valve 61 that opens and closes the communication passage 60a. As shown in FIG. 3, in the present embodiment, the pressure side valve 61 is an annular plate-like leaf valve. The outer peripheral side is allowed to bend. The outer peripheral portion of the pressure side valve 61 can be attached to and detached from a valve seat 60b that surrounds the upper end opening of the communication passage 60a.
 そして、伸側室R1の圧力は、圧側バルブ61の外周を弁座60bに押し付けて、圧側バルブ61を閉弁させる方向に作用する。その一方、圧側室R2の圧力は、連通路60aを通じて圧側バルブ61に作用し、当該圧側バルブ61の外周部を弁座60bから離座させて、圧側バルブ61を開弁する方向に作用する。 The pressure in the extension side chamber R1 acts in a direction to close the pressure side valve 61 by pressing the outer periphery of the pressure side valve 61 against the valve seat 60b. On the other hand, the pressure in the pressure side chamber R2 acts on the pressure side valve 61 through the communication passage 60a, and acts in a direction to open the pressure side valve 61 by separating the outer periphery of the pressure side valve 61 from the valve seat 60b.
 また、本実施の形態において圧側バルブ61はチェックバルブであり、圧側室R2の圧力が伸側室R1の圧力を上回ると、圧側バルブ61の外周部が弁座60bから離れて連通路60aを速やかに開放する。 Further, in the present embodiment, the pressure side valve 61 is a check valve, and when the pressure in the pressure side chamber R2 exceeds the pressure in the expansion side chamber R1, the outer periphery of the pressure side valve 61 moves away from the valve seat 60b and quickly passes through the communication passage 60a. Open.
 上記圧側バルブ61が離着座する弁座60bには、切欠きが形成されている。そして、当該切欠きによってオリフィス62が形成される。このため、圧側バルブ61が閉弁し、圧側バルブ61の外周部が弁座60bに着座した状態であっても、伸側室R1と圧側室R2は、上記オリフィス62を介して連通される。 A notch is formed in the valve seat 60b on which the pressure side valve 61 is seated. The orifice 62 is formed by the notch. Therefore, even when the pressure side valve 61 is closed and the outer peripheral portion of the pressure side valve 61 is seated on the valve seat 60b, the expansion side chamber R1 and the pressure side chamber R2 are communicated with each other through the orifice 62.
 なお、圧側バルブ61の構成は適宜変更できる。例えば、圧側バルブ61がポペット弁等、リーフバルブ以外のバルブであってもよい。また、オリフィス62の形成方法も上記の限りではなく、適宜変更できる。例えば、リーフバルブの外周部に切欠きを形成し、当該切欠きによってオリフィスを形成してもよい。 The configuration of the pressure side valve 61 can be changed as appropriate. For example, the pressure side valve 61 may be a valve other than a leaf valve such as a poppet valve. The method for forming the orifice 62 is not limited to the above, and can be changed as appropriate. For example, a notch may be formed in the outer peripheral portion of the leaf valve, and an orifice may be formed by the notch.
 つづいて、ロッドガイド50は、シリンダ5の上端部内周に嵌合する環状の嵌合部50aと、この嵌合部50aの上側に連なってシリンダ5外へ突出し、外径が嵌合部50aの外径よりも大きい環状の大外径部50bとを有する。そして、ロッドガイド50の外周には、嵌合部50aと大外径部50bとの境界に、環状の段差50cが形成されており、当該段差50cにシリンダ5の上端を突き当てられる。 Subsequently, the rod guide 50 is connected to the inner periphery of the upper end portion of the cylinder 5 and the outer side of the fitting portion 50a. And an annular large outer diameter portion 50b larger than the outer diameter. An annular step 50c is formed on the outer periphery of the rod guide 50 at the boundary between the fitting portion 50a and the large outer diameter portion 50b, and the upper end of the cylinder 5 is abutted against the step 50c.
 また、大外径部50bには、通孔50dが形成されている。この通孔50dにより、シリンダ5の外周であってインナーチューブ11とシリンダ5との間にできる空間と、シリンダ5外へ突出するロッド6とアウターチューブ10との間にできる空間が連通されて、これらの間を液体と気体が自由に行き来できる。つまり、通孔50dにより、液溜室R3がロッドガイド50で仕切られるのを防いでいる。 Further, a through hole 50d is formed in the large outer diameter portion 50b. By this through hole 50d, a space formed between the inner tube 11 and the cylinder 5 on the outer periphery of the cylinder 5 and a space formed between the rod 6 protruding outside the cylinder 5 and the outer tube 10 are communicated, Liquid and gas can freely move between these. That is, the liquid reservoir chamber R3 is prevented from being partitioned by the rod guide 50 by the through hole 50d.
 よって、液溜室R3の液面の位置をシリンダ5の外周まで下げて、気室Gの容積を確保でき、フロントフォークFの収縮時に気室G内の圧力が過大となるのを防止して、シールにかかる負荷を軽減できる。 Therefore, the position of the liquid level in the liquid reservoir R3 can be lowered to the outer periphery of the cylinder 5 to secure the volume of the air chamber G, and the pressure in the air chamber G can be prevented from becoming excessive when the front fork F contracts. The load on the seal can be reduced.
 さらに、液溜室R3の液面の位置をシリンダ5の外周まで下げたとしても、チューブ部材1の内部に収容される液体でインナーチューブ11の外周、アウターチューブ10の支持部10aの内周、及びブッシュ13の内周等の摺動面を潤滑できる。なお、大外径部50bの外周に切欠きを設け、当該切欠きで液体と気体の移動を許容するようにしてもよい。 Furthermore, even if the position of the liquid level of the liquid reservoir R3 is lowered to the outer periphery of the cylinder 5, the outer periphery of the inner tube 11, the inner periphery of the support portion 10a of the outer tube 10 with the liquid accommodated inside the tube member 1, The sliding surface such as the inner periphery of the bush 13 can be lubricated. Note that a cutout may be provided on the outer periphery of the large outer diameter portion 50b, and the movement of the liquid and gas may be allowed by the cutout.
 上記構成によれば、フロントフォークFが伸長する場合、ロッド6がシリンダ5から退出してピストン60がシリンダ5内を上方へ移動する。すると、縮小される伸側室R1の液体がオリフィス62(図3)を通って拡大する圧側室R2へ移動するとともに、伸側連通孔5aを通って液溜室L3へ移動する。 According to the above configuration, when the front fork F extends, the rod 6 moves out of the cylinder 5 and the piston 60 moves upward in the cylinder 5. Then, the liquid in the expansion side chamber R1 to be reduced moves to the pressure side chamber R2 that expands through the orifice 62 (FIG. 3), and also moves to the liquid reservoir chamber L3 through the expansion side communication hole 5a.
 伸側室R1から圧側室R2又は液溜室L3へ向かう液体の流れに対しては、オリフィス62又は伸側連通孔5aによって抵抗が与えられるので、伸側室R1の圧力が上昇し、フロントフォークFの伸長作動を妨げる伸側減衰力が発生する。また、フロントフォークFが伸長する場合、シリンダ5から退出するロッド体積分の液体がシリンダ5内で不足するが、その不足分の液体は、圧側連通孔5bを介して液溜室R3から圧側室R2へ供給される。 The flow of liquid from the expansion side chamber R1 to the pressure side chamber R2 or the liquid reservoir L3 is resisted by the orifice 62 or the expansion side communication hole 5a, so that the pressure in the expansion side chamber R1 rises and the front fork F The extension side damping force that prevents the extension operation is generated. Further, when the front fork F extends, the rod volume of liquid that retreats from the cylinder 5 is insufficient in the cylinder 5, but the insufficient liquid is supplied from the liquid reservoir chamber R <b> 3 through the pressure side communication hole 5 b. To R2.
 また、フロントフォークFの伸長側へのストローク量が通常のストローク範囲を超えて大きくなると、ピストン60が伸側連通孔5aを超えて上方へ移動する。すると、伸側室R1の液体が伸側連通孔5aを通って液溜室R3へ移動できなくなるので、伸側室R1の液体はオリフィス62(図3)のみを通って伸側室R1外へ流出するようになる。 Further, when the stroke amount to the extension side of the front fork F increases beyond the normal stroke range, the piston 60 moves upward beyond the extension side communication hole 5a. Then, the liquid in the extension side chamber R1 cannot move to the liquid storage chamber R3 through the extension side communication hole 5a, so that the liquid in the extension side chamber R1 flows out of the extension side chamber R1 only through the orifice 62 (FIG. 3). become.
 つまり、フロントフォークFの伸長側へのストローク量が大きくなると、伸側室R1外へ流出する液体の流れを許容する流路の流路面積が小さくなるので、ダンパ脚(第二脚部L2)の発揮する伸側減衰力が大きくなる。 That is, when the stroke amount to the extension side of the front fork F increases, the flow passage area of the flow passage that allows the flow of the liquid flowing out of the extension side chamber R1 decreases, so that the damper leg (second leg portion L2) The extension side damping force is increased.
 反対に、フロントフォークFが収縮する場合、ロッド6がシリンダ5内に進入してピストン60がシリンダ5内を下方へ移動する。すると、縮小される圧側室R2の液体が圧側バルブ61を開き、連通路60aを通って伸側室R1へ移動する。前述のように、圧側バルブ61はチェックバルブであるので、フロントフォークFの収縮時において、伸側室R1と圧側室R2の圧力は略同圧になる。 On the contrary, when the front fork F contracts, the rod 6 enters the cylinder 5 and the piston 60 moves downward in the cylinder 5. Then, the liquid in the pressure side chamber R2 to be reduced opens the pressure side valve 61 and moves to the extension side chamber R1 through the communication path 60a. As described above, since the pressure side valve 61 is a check valve, when the front fork F is contracted, the pressures in the extension side chamber R1 and the pressure side chamber R2 are substantially equal.
 また、フロントフォークFの収縮時には、シリンダ5内に進入するロッド体積分の液体がシリンダ5内で余剰になるので、この余剰分の液体が圧側連通孔5bを通り、圧側室R2から液溜室R3へ移動する。すると、当該液体の流れに対して圧側連通孔5bによって抵抗が与えられるので、シリンダ5内の圧力が上昇し、フロントフォークFの収縮作動を妨げる圧側減衰力が発生する。 Further, when the front fork F is contracted, the liquid for the volume of the rod that enters the cylinder 5 becomes surplus in the cylinder 5, so that the surplus liquid passes through the pressure side communication hole 5b and passes from the pressure side chamber R2 to the liquid reservoir chamber. Move to R3. Then, since resistance is given to the flow of the liquid by the pressure side communication hole 5b, the pressure in the cylinder 5 rises, and a pressure side damping force that prevents the contraction operation of the front fork F is generated.
 つづいて、ピストン60の下側に設けたスペーサ7及び第二コイルばね21は、圧側室R2内に配置されている。スペーサ7は、図4に示すように、柱状の本体部7aと、本体部7aの下端から下方へ突出し、外周に第二コイルばね21が嵌合する凸部7bとを有する。 Subsequently, the spacer 7 and the second coil spring 21 provided on the lower side of the piston 60 are disposed in the compression side chamber R2. As shown in FIG. 4, the spacer 7 includes a columnar main body portion 7 a and a convex portion 7 b that protrudes downward from the lower end of the main body portion 7 a and into which the second coil spring 21 is fitted.
 本体部7aの横断面は、軸方向に略一定であり、略十字状となっている。言い換えると、本体部7aは、その中心部7cから径方向外側へ四条の突条7dが放射状に延びた形状となっている。隣り合う突条7d,7dの間にできる窪みをそれぞれ切欠き7eとすると、各切欠き7eは、本体部7aの軸方向の一端から他端にかけて連続して形成されている。 The cross section of the main body portion 7a is substantially constant in the axial direction and has a substantially cross shape. In other words, the main body portion 7a has a shape in which four protrusions 7d extend radially outward from the center portion 7c in the radial direction. Assuming that the recesses formed between the adjacent protrusions 7d and 7d are cutouts 7e, the cutouts 7e are continuously formed from one end to the other end in the axial direction of the main body portion 7a.
 また、全ての突条7dの先端を結ぶ円の直径を本体部7aの外径とすると、当該本体部7aの外径は、シリンダ5の内径よりも小さく、凸部7bの外径よりも大きい。このため、スペーサ7は、第二コイルばね21に積層された状態でシリンダ5内を上下に移動できる。さらに、圧側室R2内の液体は、突条7dとシリンダ5との間にできる隙間、及び切欠き7eによってスペーサ7とシリンダ5との間にできる隙間を自由に移動できる。よって、圧側室R2がスペーサ7で仕切られたり、圧側連通孔5bがスペーサ7で塞がれたりすることがなく、圧側室R2にスペーサ7があっても第二脚部L2がダンパとして機能して減衰力を発揮できる。 Further, if the diameter of the circle connecting the tips of all the protrusions 7d is the outer diameter of the main body portion 7a, the outer diameter of the main body portion 7a is smaller than the inner diameter of the cylinder 5 and larger than the outer diameter of the convex portion 7b. . For this reason, the spacer 7 can move up and down in the cylinder 5 while being stacked on the second coil spring 21. Furthermore, the liquid in the pressure side chamber R2 can freely move in the gap formed between the protrusion 7d and the cylinder 5 and the gap formed between the spacer 7 and the cylinder 5 by the notch 7e. Therefore, the pressure side chamber R2 is not partitioned by the spacer 7 and the pressure side communication hole 5b is not blocked by the spacer 7. Even if the pressure side chamber R2 has the spacer 7, the second leg L2 functions as a damper. Can exert damping force.
 つづいて、スペーサ7の下側に設けた第二コイルばね21は、図2に示すように、その上端部が凸部7bに嵌合した状態で上端が本体部7aの下面に当接するとともに、その下端がアクスルブラケットBLの底部b2で支えられている。そして、フロントフォークFの収縮量が小さいストローク領域では、スペーサ7の上端がロッド6の下端から離れ、第二コイルばね21の弾性力がロッド6に伝わらない。 Next, as shown in FIG. 2, the second coil spring 21 provided on the lower side of the spacer 7 has its upper end abutted against the lower surface of the main body portion 7a with its upper end fitted to the convex portion 7b. The lower end is supported by the bottom b2 of the axle bracket BL. In the stroke region where the contraction amount of the front fork F is small, the upper end of the spacer 7 is separated from the lower end of the rod 6, and the elastic force of the second coil spring 21 is not transmitted to the rod 6.
 しかし、フロントフォークFの収縮量が所定よりも大きくなってロッド6の下端がスペーサ7に突き当たると、第二コイルばね21がロッド6とアクスルブラケットBLとの間で圧縮されて、圧縮量に応じた弾性力を発揮する。当該第二コイルばね21の弾性力は、スペーサ7を介してロッド6を押し上げる方向へ作用する。 However, when the contraction amount of the front fork F becomes larger than a predetermined value and the lower end of the rod 6 hits the spacer 7, the second coil spring 21 is compressed between the rod 6 and the axle bracket BL, and the amount of compression depends on the compression amount. Demonstrate the elastic force. The elastic force of the second coil spring 21 acts in the direction of pushing up the rod 6 via the spacer 7.
 よって、第二コイルばね21はストロークの途中から収縮側の一部のストローク領域でのみ機能して、フロントフォークFを伸長方向へ附勢する。なお、本実施の形態において、ロッド6の下端がピストン60の下方へ突出しており、当該部分にスペーサ7が突き当たる。しかし、ピストン60の下面にスペーサ7を突き当てるとしてもよい。 Therefore, the second coil spring 21 functions only in a partial stroke region on the contraction side from the middle of the stroke, and urges the front fork F in the extending direction. In the present embodiment, the lower end of the rod 6 projects downward from the piston 60, and the spacer 7 strikes the portion. However, the spacer 7 may be abutted against the lower surface of the piston 60.
 以下、本実施の形態に係るフロントフォークFの作動について説明する。 Hereinafter, the operation of the front fork F according to the present embodiment will be described.
 車両が凹凸のある路面を走行する等して前輪Wが上下に移動すると、第一脚部L1と第二脚部L2のインナーチューブ11がアウターチューブ10に出入りしてフロントフォークFが伸縮する。すると、ダンパ脚である第二脚部L2がダンパとして機能して減衰力を発揮するとともに、第一コイルばね20と第二コイルばね21とを有して構成される懸架ばね2が圧縮量に応じた弾性力を発揮する。 When the front wheel W moves up and down as the vehicle travels on an uneven road surface, the inner tube 11 of the first leg L1 and the second leg L2 enters and exits the outer tube 10 and the front fork F expands and contracts. Then, the second leg portion L2 which is a damper leg functions as a damper and exhibits a damping force, and the suspension spring 2 configured to include the first coil spring 20 and the second coil spring 21 is compressed. Delivers the corresponding elastic force.
 より詳しくは、第二コイルばね21が圧縮を開始するストローク位置をP(図5)とすると、第二コイルばね21は、当該ストローク位置Pよりも伸長側のストローク領域Xで機能せず、ストローク位置Pよりも収縮側のストローク領域Yで機能する。よって、第二コイルばね21が機能しないストローク領域Xでは、実質的に第一コイルばね20のみが懸架ばね2として機能する。このため、当該ストローク領域Xでの懸架ばね2のばね定数は、第一コイルばね20のばね定数に等しくなる。 More specifically, if the stroke position at which the second coil spring 21 starts compression is P (FIG. 5), the second coil spring 21 does not function in the stroke region X on the extension side of the stroke position P, and the stroke It functions in the stroke area Y on the contraction side with respect to the position P. Accordingly, in the stroke region X where the second coil spring 21 does not function, only the first coil spring 20 substantially functions as the suspension spring 2. For this reason, the spring constant of the suspension spring 2 in the stroke region X is equal to the spring constant of the first coil spring 20.
 その一方、第二コイルばね21が機能するストローク領域Yでは、第一コイルばね20と第二コイルばね21の両方が懸架ばね2として機能する。このため、当該ストローク領域Yでの懸架ばね2のばね定数は、第一コイルばね20のばね定数と、第二コイルばね21のばね定数の合成のばね定数となる。すると、ストローク領域Yでの懸架ばね2のばね定数がストローク領域Xでの懸架ばね2のばね定数よりも大きくなる。 On the other hand, in the stroke region Y where the second coil spring 21 functions, both the first coil spring 20 and the second coil spring 21 function as the suspension spring 2. For this reason, the spring constant of the suspension spring 2 in the stroke region Y is a combined spring constant of the spring constant of the first coil spring 20 and the spring constant of the second coil spring 21. Then, the spring constant of the suspension spring 2 in the stroke region Y becomes larger than the spring constant of the suspension spring 2 in the stroke region X.
 よって、図5に示すように、収縮側へのストローク量が所定(ストローク位置P)よりも大きくなったストローク領域Yで懸架ばね2のばね定数が大きくなり、ストローク量に対する懸架ばね2の弾性力が大きくなる。 Therefore, as shown in FIG. 5, the spring constant of the suspension spring 2 is increased in the stroke region Y where the stroke amount toward the contraction side is larger than the predetermined (stroke position P), and the elastic force of the suspension spring 2 with respect to the stroke amount. Becomes larger.
 言い換えると、フロントフォークFでは、収縮量が所定よりも大きくなった場合に大きなばね定数に切り換わるようなストローク依存性を懸架ばね2に持たせている。そして、フロントフォークFの収縮量が小さなストローク領域Xでは懸架ばね2の弾性力を小さくし、上記収縮量が大きなストローク領域Yでは懸架ばね2の弾性力を大きくしている。 In other words, in the front fork F, the suspension spring 2 has a stroke dependency that switches to a large spring constant when the contraction amount becomes larger than a predetermined amount. The elastic force of the suspension spring 2 is reduced in the stroke region X where the contraction amount of the front fork F is small, and the elastic force of the suspension spring 2 is increased in the stroke region Y where the contraction amount is large.
 このため、例えば、搭乗者が運転者のみである場合等、積載荷重が小さい場合の懸架ばね2の弾性力を小さくして車両の乗り心地を良好にできる。また、同乗者、積荷等の影響で積載荷重が大きくなる場合の懸架ばね2の弾性力を大きくして、フロントフォークFの底付き(最圧縮状態になること)頻度を低減できる。つまり、フロントフォークFでは、懸架ばね2のばね定数をストローク量に応じて切り換えて積載荷重に応じたばね定数なるように設定できるので、車両の乗り心地を良好にできる。 For this reason, for example, when the passenger is only the driver, the elastic force of the suspension spring 2 when the loaded load is small can be reduced to improve the riding comfort of the vehicle. Further, the elastic force of the suspension spring 2 when the loaded load becomes large due to the influence of passengers, cargo, etc. can be increased, and the frequency with which the front fork F is bottomed (becomes the most compressed state) can be reduced. That is, in the front fork F, the spring constant of the suspension spring 2 can be switched according to the stroke amount so as to be a spring constant according to the load, so that the riding comfort of the vehicle can be improved.
 さらに、フロントフォークFが通常のストローク範囲を超えて伸長する場合には、第一脚部L1の伸切ばね4の弾性力と、第二脚部L2の大きな伸側減衰力でフロントフォークFの伸長速度を減速できる。よって、フロントフォークFの最伸長時の衝撃を緩和して、車両の乗り心地を一層良好にできる。 Further, when the front fork F extends beyond the normal stroke range, the front fork F has an elastic force of the extending spring 4 of the first leg L1 and a large extension side damping force of the second leg L2. The extension speed can be reduced. Therefore, the impact when the front fork F is fully extended can be alleviated, and the riding comfort of the vehicle can be further improved.
 本実施の形態において、第二コイルばね21は、スペーサ7を介して圧縮される。このため、例えば、スペーサ7を長さの異なるスペーサに変更すれば、懸架ばね2のばね定数を切り換えるストローク位置Pを変更できる。つまり、第二コイルばね21を変更せずにストローク位置Pを変更できるので、当該ストローク位置Pの調整が容易である。 In the present embodiment, the second coil spring 21 is compressed via the spacer 7. For this reason, for example, if the spacer 7 is changed to a spacer having a different length, the stroke position P for switching the spring constant of the suspension spring 2 can be changed. That is, since the stroke position P can be changed without changing the second coil spring 21, the stroke position P can be easily adjusted.
 さらに、上記スペーサ7は、ピストン60と第二コイルばね21との間に配置されている。このため、スペーサ7をばね受けとして利用でき、ピストン60又はロッド6にばね受けを設ける必要がない。また、上記スペーサ7は、ピストン60及びロッド6と分離可能に設けられている。このため、スペーサ7の交換が容易である。 Furthermore, the spacer 7 is disposed between the piston 60 and the second coil spring 21. For this reason, the spacer 7 can be used as a spring receiver, and there is no need to provide a spring receiver on the piston 60 or the rod 6. The spacer 7 is provided so as to be separable from the piston 60 and the rod 6. For this reason, replacement of the spacer 7 is easy.
 また、上記スペーサ7は、柱状の本体部7aと、本体部7aの下端(軸方向の一方側端部)に連なり外径が本体部7aの外径よりも小さい凸部7bとを有する。そして、第二コイルばね21が凸部7bの外周に嵌合する。このため、当該凸部7bでスペーサ7と第二コイルばね21が横方向にずれるのを防ぎ、第二コイルばね21にかかる荷重が偏るのを抑制できる。 The spacer 7 has a columnar main body 7a and a convex portion 7b that is connected to the lower end (one end in the axial direction) of the main body 7a and has an outer diameter smaller than the outer diameter of the main body 7a. And the 2nd coil spring 21 fits to the outer periphery of the convex part 7b. For this reason, it can prevent that the spacer 7 and the 2nd coil spring 21 shift | deviate laterally by the said convex part 7b, and can suppress that the load concerning the 2nd coil spring 21 is biased.
 さらに、本体部7aの外径がシリンダ5の内径よりも小さく、本体部7aの外周に軸方向の一端から他端にかけて連続する切欠き7eが形成されている。このため、スペーサ7を圧側室R2内に設けても、スペーサ7で圧側室R2を仕切ることがない。加えて、スペーサ7が伸側室R1と圧側室R2との間を行き来する液体の流れ、及び圧側室R2と液溜室R3との間を行き来する液体の流れの妨げにならず、減衰力発生の妨げにならない。 Further, the outer diameter of the main body portion 7a is smaller than the inner diameter of the cylinder 5, and a notch 7e is formed on the outer periphery of the main body portion 7a so as to continue from one end to the other end in the axial direction. For this reason, even if the spacer 7 is provided in the pressure side chamber R2, the pressure side chamber R2 is not partitioned by the spacer 7. In addition, the spacer 7 does not hinder the flow of the liquid flowing back and forth between the expansion side chamber R1 and the pressure side chamber R2, and the flow of the liquid flowing back and forth between the pressure side chamber R2 and the liquid storage chamber R3, and generates a damping force. Will not hinder.
 また、スペーサ7を合成樹脂で形成すると、スペーサを軽量化できるとともに形状の設計自由度が高いので、前述のように凸部7bを設けたり、切欠き7eを設けたりするのが容易である。 Further, when the spacer 7 is formed of a synthetic resin, the spacer can be reduced in weight and the design freedom of the shape is high. Therefore, as described above, it is easy to provide the convex portion 7b or the notch 7e.
 なお、スペーサ7の構成は上記の限りではなく、形状、素材、及び配置を適宜変更できる。例えば、スペーサをピストン60又はロッド6に連結してこれらを一体化してもよく、第二コイルばね21の下側に設けてもよい。さらに、ストローク位置Pを任意に設定できれば、スペーサを廃するとしてもよい。 The configuration of the spacer 7 is not limited to the above, and the shape, material, and arrangement can be changed as appropriate. For example, the spacer may be connected to the piston 60 or the rod 6 to integrate them, or may be provided below the second coil spring 21. Further, if the stroke position P can be set arbitrarily, the spacer may be eliminated.
 また、本実施の形態において、第二脚部(他方の脚部)L2は、ダンパとして機能するダンパ脚であり、内部に収容する液体の流れに抵抗を与えて減衰力を発揮するが、第一脚部(一方の脚部)L1はこのような機能を有していない。そして、懸架ばね2を構成する第一コイルばね20と第二コイルばね21のうち、長い方の第一コイルばね20が第一脚部L1に収容され、短い方の第二コイルばね21が第二脚部L2に収容される。 Further, in the present embodiment, the second leg (the other leg) L2 is a damper leg that functions as a damper, and exerts a damping force by imparting resistance to the flow of liquid contained therein. The monopod (one leg) L1 does not have such a function. Of the first coil spring 20 and the second coil spring 21 constituting the suspension spring 2, the longer first coil spring 20 is accommodated in the first leg L1, and the shorter second coil spring 21 is the first coil spring 21. Housed in the bipod L2.
 つまり、上記構成によれば、減衰力の発生に必要な部品(シリンダ5、ロッド6、ピストン60等)を収容しない第一脚部L1に全長の長い第一コイルばね20が収容される。このため、第一コイルばね20の長さが長くても第一脚部L1が軸方向に嵩張るのを抑制できる。 That is, according to the above configuration, the long first coil spring 20 is accommodated in the first leg L1 that does not accommodate components (cylinder 5, rod 6, piston 60, etc.) necessary for generating the damping force. For this reason, even if the length of the 1st coil spring 20 is long, it can suppress that the 1st leg part L1 is bulky in an axial direction.
 また、第二脚部L2に収容される第二コイルばね21の長さは第一コイルばね20と比較して短いので、減衰力の発生に必要な部品を収容する第二脚部L2に第二コイルばね21を収容しても、第二脚部L2が軸方向に嵩張るのを抑制できる。 Further, since the length of the second coil spring 21 accommodated in the second leg portion L2 is shorter than that of the first coil spring 20, the second leg portion L2 that accommodates the parts necessary for generating the damping force is second. Even if the two-coil spring 21 is accommodated, the second leg L2 can be prevented from being bulky in the axial direction.
 よって、上記構成によれば、フロントフォークFの格納長を短くして搭載性を良好にできる。例えば、図1に示すような、ステアリングシャフトが脚部の上端から上方へ大きく突出するような形態のフロントフォークでは、脚部の長さを長くとれない場合が多い。このため、このような形態のフロントフォークにおいては特に、上記構成を採用するのが有効である。 Therefore, according to the above configuration, the storage length of the front fork F can be shortened to improve the mountability. For example, in a front fork in which the steering shaft projects greatly upward from the upper end of the leg portion as shown in FIG. 1, the length of the leg portion cannot often be increased. For this reason, it is effective to employ the above configuration particularly in such a form of front fork.
 また、ダンパ脚である第二脚部(他方の脚部)L2は、アウターチューブ(車体側チューブ)10とインナーチューブ(車輪側チューブ)11とを有するテレスコピック型のチューブ部材1と、インナーチューブ11に連結されてその内側に配置されるシリンダ5と、シリンダ5内に摺動可能に挿入されてシリンダ5内を伸側室R1と圧側室R2とに区画するピストン60と、アウターチューブ10に連結されて先端(一端)がピストン60に連結されるロッド6とを有する。そして、チューブ部材1とシリンダ5との間には、液体が貯留されて液溜室R3が形成されており、シリンダ5には、圧側室R2から液溜室R3へ向かう液体の流れに抵抗を与える圧側連通孔5bが形成されている。 The second leg portion (the other leg portion) L2 which is a damper leg includes a telescopic tube member 1 having an outer tube (vehicle body side tube) 10 and an inner tube (wheel side tube) 11, and an inner tube 11. Are connected to the outer tube 10, are connected to the cylinder 5, are slidably inserted into the cylinder 5, are slidably inserted into the cylinder 5, and are divided into an extension side chamber R 1 and a pressure side chamber R 2. And a rod 6 whose tip (one end) is connected to the piston 60. A liquid is stored between the tube member 1 and the cylinder 5 to form a liquid storage chamber R3. The cylinder 5 resists the flow of liquid from the pressure side chamber R2 to the liquid storage chamber R3. A pressure side communication hole 5b is formed.
 上記構成によれば、フロントフォークFの収縮時にシリンダ5に進入するロッド体積分の液体がシリンダ5内で余剰となり、その分の液体が圧側連通孔5bを通って圧側室R2から液溜室R3へ移動する。よって、当該液体の流れに圧側連通孔5bで抵抗を与えて圧側減衰力を得られる。 According to the above configuration, when the front fork F contracts, the rod volume of liquid that enters the cylinder 5 becomes surplus in the cylinder 5, and the liquid passes through the pressure side communication hole 5b from the pressure side chamber R2 to the liquid reservoir chamber R3. Move to. Therefore, resistance is given to the flow of the liquid by the pressure side communication hole 5b to obtain the pressure side damping force.
 つまり、本実施の形態では、圧側連通孔5bが圧側の減衰力発生要素となっているので、圧側の減衰力発生要素の構成が非常に簡易であり、フロントフォークFの製造を容易にできる。また、圧側連通孔5bは、シリンダ5の側部に形成されるので、第二コイルばね21を圧側室R2内に配置したとき、第二脚部L2が軸方向に嵩張るのを抑制できる。 That is, in the present embodiment, the compression side communication hole 5b is a compression side damping force generation element, so the configuration of the compression side damping force generation element is very simple and the manufacture of the front fork F can be facilitated. Moreover, since the pressure side communication hole 5b is formed in the side part of the cylinder 5, when the 2nd coil spring 21 is arrange | positioned in the pressure side chamber R2, it can suppress that the 2nd leg part L2 is bulky in an axial direction.
 より詳しくは、圧側の減衰力発生要素がリーフバルブ等のバルブであって、当該バルブで圧側室R2から液溜室R3へ向かう液体の流れに抵抗を与える場合、シリンダ5の下端部に固定した隔壁部材に上記バルブを装着し、上記隔壁部材に形成した通路を通過する液体の流れに上記バルブで抵抗を与えるのが一般的である。 More specifically, the pressure-side damping force generating element is a valve such as a leaf valve, and when the valve gives resistance to the flow of liquid from the pressure-side chamber R2 to the liquid reservoir chamber R3, it is fixed to the lower end portion of the cylinder 5. Generally, the valve is attached to the partition member, and resistance is given to the flow of the liquid passing through the passage formed in the partition member by the valve.
 しかしながら、この場合、ダンパ脚の部品数が増えて構造が複雑になるとともに、隔壁部材を設ける分、第二コイルばね21を上側に配置しなければならない。よって、このようなダンパ脚の圧側室に第二コイルばね21を設ける場合、ダンパ脚が軸方向に長くなり、フロントフォークが所定のスペースに収まらなくなる可能性がある。 However, in this case, the number of parts of the damper leg is increased and the structure becomes complicated, and the second coil spring 21 must be disposed on the upper side by providing the partition member. Therefore, when the second coil spring 21 is provided in the pressure side chamber of such a damper leg, the damper leg becomes longer in the axial direction, and the front fork may not fit in a predetermined space.
 これに対して、上記構成によれば、ダンパ脚である第二脚部L2の構成を簡易にできる。さらに、第二コイルばね21の下端をアクスルブラケットBLで直接支持できるので、第二コイルばね21の支持機構も極めて簡易にできる。よって、フロントフォークFの構造を簡易にして、コストを低減できる。加えて、第二コイルばね21の位置を下げられるので、第二脚部L2が軸方向に嵩張るのを防止できる。 On the other hand, according to the above configuration, the configuration of the second leg L2 which is the damper leg can be simplified. Furthermore, since the lower end of the second coil spring 21 can be directly supported by the axle bracket BL, the support mechanism of the second coil spring 21 can be extremely simplified. Therefore, the structure of the front fork F can be simplified and the cost can be reduced. In addition, since the position of the second coil spring 21 can be lowered, it is possible to prevent the second leg portion L2 from being bulky in the axial direction.
 なお、第一脚部L1と第二脚部L2の構成は上記の限りではなく、適宜変更できる。例えば、第二脚部L2における圧側の減衰力発生要素をリーフバルブ等のバルブに変更してもよい。 In addition, the structure of the 1st leg part L1 and the 2nd leg part L2 is not restricted above, and can be changed suitably. For example, the compression-side damping force generating element in the second leg L2 may be changed to a valve such as a leaf valve.
 また、本実施の形態の第二脚部L2では、オリフィス62と伸側連通孔5aが伸側の減衰力発生要素となっている。このため、伸側の減衰力発生要素の構成が非常に簡易であり、フロントフォークFの製造を容易にできる。しかし、伸側の減衰力発生要素がオリフィス62又は伸側連通孔5aの一方のみであってもよい。また、伸側の減衰力発生要素がリーフバルブ等のバルブであってもよい。このように、ダンパ脚における伸側と圧側の減衰力発生要素の構成を適宜変更できる。 Further, in the second leg portion L2 of the present embodiment, the orifice 62 and the extension side communication hole 5a are elements for generating a damping force on the extension side. For this reason, the structure of the damping force generating element on the extension side is very simple, and the manufacture of the front fork F can be facilitated. However, the extension side damping force generation element may be only one of the orifice 62 and the extension side communication hole 5a. Further, the extension side damping force generating element may be a valve such as a leaf valve. In this way, the configuration of the damping force generating elements on the extension side and the compression side in the damper leg can be appropriately changed.
 また、本実施の形態の第二脚部L2では、圧側連通孔5bを介してシリンダ5内が液溜室L3に連通されており、ロッド出没体積分のシリンダ内容積変化、及び温度変化によるシリンダ5内の液体の体積変化を液溜室R3で補償できる。つまり、液溜室L3がリザーバの液体貯留室として機能し、チューブ部材1がリザーバのハウジングを構成する。しかし、シリンダ5内に膨縮可能な気室をフリーピストン、ブラダ等の可動隔壁で画成し、当該気室で体積補償をしてもよい。このように、第二脚部に体積補償用の気室を設ける場合には、シリンダ5を廃し、インナーチューブ11の内周にピストン60を摺接させて、インナーチューブ11をシリンダとして機能させてもよい。 Further, in the second leg portion L2 of the present embodiment, the inside of the cylinder 5 is communicated with the liquid reservoir chamber L3 via the pressure side communication hole 5b, and the cylinder volume change due to the rod protruding and retracting volume and the cylinder due to the temperature change The volume change of the liquid in 5 can be compensated by the liquid reservoir R3. That is, the liquid reservoir L3 functions as a reservoir liquid reservoir, and the tube member 1 constitutes a reservoir housing. However, an air chamber that can be expanded and contracted in the cylinder 5 may be defined by a movable partition wall such as a free piston or a bladder, and volume compensation may be performed in the air chamber. Thus, when providing a volume compensation air chamber in the second leg, the cylinder 5 is eliminated, the piston 60 is slidably contacted with the inner periphery of the inner tube 11, and the inner tube 11 functions as a cylinder. Also good.
 また、本実施の形態の第一脚部L1と第二脚部L2では、各チューブ部材1が倒立型に設定されていて、アウターチューブ10が車体側チューブ、インナーチューブ11が車輪側チューブとなっている。このため、アウターチューブとアクスルブラケットが一体化された正立型のチューブ部材を利用する場合と比較してアクスルブラケットを小型化できるので、フロントフォークを安価に形成できる。しかし、チューブ部材1を正立型にしてもよい。このように、各脚部のチューブ部材の構成は、適宜変更できる。 Moreover, in the 1st leg part L1 and 2nd leg part L2 of this Embodiment, each tube member 1 is set to the inverted type, the outer tube 10 becomes a vehicle body side tube, and the inner tube 11 becomes a wheel side tube. ing. For this reason, since an axle bracket can be reduced in size compared with the case where an upright tube member in which an outer tube and an axle bracket are integrated is used, a front fork can be formed at a low cost. However, the tube member 1 may be an upright type. Thus, the structure of the tube member of each leg can be changed as appropriate.
 そして、このような第一脚部L1と第二脚部L2の変更は、スペーサの構成、及び有無によらず可能である。また、第一脚部L1がダンパとして機能するダンパ脚であるとしてもよく、第二脚部L2がダンパとして機能しないばね脚であってもよい。 And such a change of the 1st leg part L1 and the 2nd leg part L2 is possible irrespective of the structure of a spacer, and the presence or absence. Further, the first leg portion L1 may be a damper leg that functions as a damper, and the second leg portion L2 may be a spring leg that does not function as a damper.
 また、本実施の形態において、フロントフォークFは、前輪(車輪)Wを支持する第一脚部L1及び第二脚部L2(一対の脚部)と、車体を弾性支持する懸架ばね2とを備える。そして、この懸架ばね2は、第一脚部(一方の脚部)L1に収容されてフロントフォークFのストローク全域で弾性力を発揮する第一コイルばね20と、第二脚部(他方の脚部)L2に収容されてストロークの途中から収縮側のストローク領域Yで弾性力を発揮する第二コイルばね21とを有して構成される。 In the present embodiment, the front fork F includes a first leg L1 and a second leg L2 (a pair of legs) that support the front wheel (wheel) W, and a suspension spring 2 that elastically supports the vehicle body. Prepare. The suspension spring 2 includes a first coil spring 20 that is accommodated in the first leg portion (one leg portion) L1 and exhibits an elastic force over the entire stroke of the front fork F, and a second leg portion (the other leg portion). Part) The second coil spring 21 that is housed in L2 and that exerts an elastic force in the stroke region Y on the contraction side from the middle of the stroke.
 上記構成によれば、第一コイルばね20のみが機能するストローク領域Xと、第一コイルばね20と第二コイルばね21の両方が機能するストローク領域Yができるので、懸架ばね2のばね定数をストローク量に応じて変更できる。 According to the above configuration, the stroke region X in which only the first coil spring 20 functions and the stroke region Y in which both the first coil spring 20 and the second coil spring 21 function are formed. It can be changed according to the stroke amount.
 また、上記構成によれば、第一コイルばね20と第二コイルばね21が並列に力を発揮するので、懸架ばね2として第一コイルばね20と第二コイルばね21の二種類のコイルばねを利用したとしても、二つのコイルばねの合成のばね定数がコイルばね単体でのばね定数よりも大きくなる。このため、二種類のコイルばねが直列に力を発揮する多段コイルばねを利用した従来のフロントフォークと比較して、懸架ばね全体としてのコイルばねの巻数を削減できる。よって、懸架ばねの重量が軽くなり、コストを低減できる。 Moreover, according to the said structure, since the 1st coil spring 20 and the 2nd coil spring 21 exhibit force in parallel, two types of coil springs, the 1st coil spring 20 and the 2nd coil spring 21, are used as the suspension spring 2. Even if it is used, the combined spring constant of the two coil springs is larger than the spring constant of the coil spring alone. For this reason, the number of turns of the coil spring as a whole suspension spring can be reduced as compared with a conventional front fork using a multistage coil spring in which two types of coil springs exert a force in series. Therefore, the weight of the suspension spring is reduced, and the cost can be reduced.
 さらに、上記構成によれば、第一コイルばね20と第二コイルばね21が一対の脚部に個別に収容されているので、各脚部の径が大きくなるのを防止できる。よって、フロントフォークFを小型化し、フロントフォークの軽量化と更なるコストの低減が可能になる。 Furthermore, according to the above configuration, since the first coil spring 20 and the second coil spring 21 are individually accommodated in the pair of leg portions, it is possible to prevent the diameter of each leg portion from increasing. Therefore, the front fork F can be reduced in size, and the front fork can be reduced in weight and further reduced in cost.
 なお、本実施の形態では、フロントフォークFにおける全ストローク領域の略中央で、懸架ばね2のばね定数が切り換わる。しかし、懸架ばね2のばね定数が切り換わるストローク位置Pは、所望の懸架ばね2のばね特性に応じて適宜変更できる。そして、当該変更は、スペーサの構成及び有無、並びに、一対の脚部の構成によらず可能である。 In the present embodiment, the spring constant of the suspension spring 2 is switched approximately at the center of the entire stroke area of the front fork F. However, the stroke position P at which the spring constant of the suspension spring 2 is switched can be appropriately changed according to the desired spring characteristic of the suspension spring 2. The change can be made regardless of the configuration and presence of the spacer and the configuration of the pair of legs.
 以上、本発明の好ましい実施の形態を詳細に説明したが、特許請求の範囲から逸脱しない限り、改造、変形及び変更が可能である。 The preferred embodiments of the present invention have been described above in detail, but modifications, changes and modifications can be made without departing from the scope of the claims.
 本願は、2016年12月9日に日本国特許庁に出願された特願2016-239681に基づく優先権を主張し、この出願の全ての内容は参照により本明細書に組み込まれる。 This application claims priority based on Japanese Patent Application No. 2016-239681 filed with the Japan Patent Office on December 9, 2016, the entire contents of which are hereby incorporated by reference.

Claims (5)

  1.  フロントフォークであって、
     車輪を支持する一対の脚部と、
     車体を弾性支持する懸架ばねとを備え、
     前記懸架ばねは、前記一対の脚部のうちの一方の脚部に収容されて、ストローク全域で弾性力を発揮する第一コイルばねと、前記一対の脚部のうちの他方の脚部に収容されて、ストロークの途中から収縮側のストローク領域で弾性力を発揮する第二コイルばねとを有して構成されている
     フロントフォーク。
    A front fork,
    A pair of legs that support the wheels;
    A suspension spring that elastically supports the vehicle body,
    The suspension spring is accommodated in one leg of the pair of legs, and is accommodated in the other leg of the pair of legs, and a first coil spring that exerts elasticity over the entire stroke. And a second fork configured to have a second coil spring that exhibits elasticity in the stroke region on the contraction side from the middle of the stroke.
  2.  請求項1に記載のフロントフォークであって、
     前記他方の脚部のみが内部に収容する液体の流れに抵抗を与えて減衰力を発揮するダンパとして機能する
     フロントフォーク。
    The front fork according to claim 1,
    A front fork that functions as a damper that exerts a damping force by applying resistance to the flow of liquid contained in the other leg only.
  3.  請求項2に記載のフロントフォークであって、
     前記他方の脚部は、車体側チューブと車輪側チューブとを有するテレスコピック型のチューブ部材と、前記車輪側チューブに連結されてその内側に配置されるシリンダと、前記シリンダ内に摺動可能に挿入されて前記シリンダ内を伸側室と圧側室とに区画するピストンと、前記車体側チューブに連結されて一端が前記ピストンに連結されるロッドとを有し、
     前記チューブ部材と前記シリンダとの間には、液体が貯留されて液溜室が形成されており、
     前記シリンダには、前記圧側室から前記液溜室へ向かう液体の流れに抵抗を与える圧側連通孔が形成されており、
     前記第二コイルばねは、前記圧側室内に配置されている
     フロントフォーク。
    The front fork according to claim 2,
    The other leg portion is a telescopic tube member having a vehicle body side tube and a wheel side tube, a cylinder connected to the wheel side tube and disposed inside thereof, and slidably inserted into the cylinder. A piston that divides the cylinder into an extension side chamber and a pressure side chamber, and a rod that is connected to the vehicle body side tube and has one end connected to the piston,
    Between the tube member and the cylinder, a liquid is stored to form a liquid storage chamber,
    The cylinder is formed with a pressure side communication hole that gives resistance to a flow of liquid from the pressure side chamber toward the liquid reservoir.
    The second coil spring is disposed in the pressure side chamber.
  4.  請求項1に記載のフロントフォークであって、
     前記第二コイルばねは、スペーサを介して圧縮される
     フロントフォーク。
    The front fork according to claim 1,
    The second coil spring is a front fork that is compressed through a spacer.
  5.  請求項3に記載のフロントフォークであって、
     前記第二コイルばねと前記ピストンとの間に介装されるスペーサを備え、
     前記スペーサは、柱状の本体部と、前記本体部の軸方向の一方側端部に連なり外径が前記本体部の外径よりも小さく外周に前記第二コイルばねの一端が嵌合する凸部とを有し、
     前記本体部の外径は、前記シリンダの内径よりも小さく、
     前記本体部の外周には、軸方向の一端から他端にかけて連続する切欠きが形成されている
     フロントフォーク。
     
    The front fork according to claim 3,
    A spacer interposed between the second coil spring and the piston;
    The spacer includes a column-shaped main body portion and a convex portion which is connected to one end portion in the axial direction of the main body portion and whose outer diameter is smaller than the outer diameter of the main body portion and one end of the second coil spring is fitted to the outer periphery. And
    The outer diameter of the main body is smaller than the inner diameter of the cylinder,
    A front fork in which a notch continuous from one end to the other end in the axial direction is formed on the outer periphery of the main body.
PCT/JP2017/043940 2016-12-09 2017-12-07 Front forks WO2018105683A1 (en)

Applications Claiming Priority (2)

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JP2016-239681 2016-12-09
JP2016239681A JP2018096412A (en) 2016-12-09 2016-12-09 Front fork

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0641276B2 (en) * 1985-05-13 1994-06-01 ヤマハ発動機株式会社 Front fork of motorcycle
JP2003097615A (en) * 2001-09-21 2003-04-03 Showa Corp Multistep coil spring
JP2004232705A (en) * 2003-01-29 2004-08-19 Showa Corp Front fork unit of motorcycle and the like
JP2005239052A (en) * 2004-02-27 2005-09-08 Honda Motor Co Ltd Front fork for motorcycle
JP2017161008A (en) * 2016-03-10 2017-09-14 株式会社ショーワ Suspension device

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0641276B2 (en) * 1985-05-13 1994-06-01 ヤマハ発動機株式会社 Front fork of motorcycle
JP2003097615A (en) * 2001-09-21 2003-04-03 Showa Corp Multistep coil spring
JP2004232705A (en) * 2003-01-29 2004-08-19 Showa Corp Front fork unit of motorcycle and the like
JP2005239052A (en) * 2004-02-27 2005-09-08 Honda Motor Co Ltd Front fork for motorcycle
JP2017161008A (en) * 2016-03-10 2017-09-14 株式会社ショーワ Suspension device

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