JP2010084924A - Front fork - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable spring force adjustment of a suspension spring while ensuring telescopic motion of a damper mounted in a fork body. <P>SOLUTION: A jack mechanism moves up/down the upper end position of the suspension spring S which is mounted in the fork body consisting of a vehicle body side tube 1 and a wheel side tube 2, to enable the spring force adjustment of the suspension spring S. It includes has a lower end side portion 11a of a cap member 11 for closing the upper end opening of the vehicle body side tube 1, and a piston member 12 slidably linked to the lower end side portion 11a to define a pressure chamber R3 which is expanded/contracted between the lower end side portion 11a and itself. The pressure chamber R3 is expanded/contracted with the supply/discharge of pressure oil thereto/therefrom, whereby the piston member 12 is moved up/down relative to the cap member 11 to move up/down the upper end position of the suspension spring S. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a front fork, and more particularly, to an improvement in a front fork that is mounted on a front wheel side of a two-wheeled vehicle and absorbs road surface vibrations input to the front wheel while suspending the front wheel of the two-wheeled vehicle.

  There are various proposals so far as a front fork as a hydraulic shock absorber that is mounted on the front wheel side of a motorcycle and absorbs road surface vibrations input to the front wheel while suspending the front wheel of the motorcycle, For example, Patent Document 1 discloses a proposal of a front fork that can adjust the height of a spring force of a suspension spring accommodated in a fork main body to increase or decrease the height of a motorcycle.

  That is, the front fork disclosed in Patent Document 1 has a plunger serving as a piston that is in contact with the upper end of the suspension spring of the housing and is in series in the fork body composed of the vehicle body side tube and the wheel side tube. Do it.

  And in this front fork, the above-mentioned plunger slides in the axial direction of the suspension spring by supplying and discharging pressure oil from the outside of the fork body, and adjusts the spring force of the suspension spring by raising and lowering the upper end position of the suspension spring To do.

  At this time, the plunger is slidably accommodated in a cylinder disposed on the shaft core portion on the upper end side of the vehicle body side tube, and the lower end protruding from the cylinder locks the upper end of the cylindrical spacer. The lower end of the spacer is carried on the upper end of the suspension spring.

Therefore, in the front fork disclosed in Patent Document 1, for example, the plunger is slid by driving a hydraulic supply / exhaust source provided on the vehicle body, and the upper end position of the suspension spring is moved up and down to move the suspension spring. The spring force can be adjusted, that is, the vehicle height of the two-wheeled vehicle can be adjusted.
Japanese Patent Application Laid-Open No. Hei 4-8934 (see the upper left column of the specification page 3, the lower left column of the fourth page, see FIGS. 1 and 4)

  However, in the front fork disclosed in Patent Document 1 described above, basically, the height of the two-wheeled vehicle can be adjusted by adjusting the strength of the spring force of the suspension spring accommodated in the fork body. Although there is no problem, there is a possibility that it may be pointed out that there is a minor defect when considering the actual use.

  That is, in the above-mentioned front fork, it is understood that a damper having a damping action corresponding to the operation of the suspension spring is housed in the fork body, but from the point disclosed in the drawing, the damper is It can be understood that the constituting rod body is connected to the plunger.

  However, when the damper is housed in the fork main body, the damper is configured to expand and contract in synchronization with the expansion and contraction of the fork main body. For this purpose, the cylinder body constituting the damper and the cylinder body can be projected and retracted. It is preferable that the rod body to be inserted is fixedly connected to the fork main body.

  If so, in the front fork disclosed in Patent Document 1 described above, the rod body is connected to a plunger that is slidably mounted on the cylinder, and is not directly connected to the fork main body.

  As a result, in the above-mentioned front fork, the axial direction as the expansion / contraction direction of the damper does not coincide with the axial direction as the expansion / contraction direction of the fork body, and therefore it is difficult to ensure the smooth expansion / contraction operation of the damper with respect to the expanding / reducing fork body. There is.

  The present invention was devised in view of such a current situation, and the object of the present invention is to adjust the spring force of the suspension spring while ensuring the expansion and contraction operation of the damper disposed in the fork body. Thus, it is to provide a front fork that is optimal for expecting improvement in its versatility.

  In order to achieve the above-mentioned object, the front fork according to the present invention is basically configured so that the upper end position of the suspension spring accommodated in the fork main body comprising the vehicle body side tube and the wheel side tube is the above fork main body. In the front fork that allows the spring force of the suspension spring to be adjusted by moving it up and down by driving the jack mechanism in the housing, the jack mechanism in the cap member that closes the upper end opening of the vehicle body side tube A lower end side portion and a piston member that is slidably connected to the lower end side portion of the cap member and defines a pressure chamber that expands and contracts between the lower end side portion and a pressure against the pressure chamber. The pressure chamber is expanded and contracted by supplying and discharging oil, and the piston member is raised and lowered with respect to the cap member, and the upper end position of the suspension spring is raised and lowered. The to.

  Therefore, according to the present invention, in the jack mechanism housed in the fork main body, the piston member that raises and lowers the upper end position of the suspension spring is in sliding contact with the lower end side portion of the cap member that closes the upper end opening of the vehicle body side tube. However, since a pressure chamber is defined between the pressure member and the cap member, the piston member can be moved up and down by supplying and discharging pressure oil to and from the pressure chamber, and the upper end position of the suspension spring can be moved up and down.

  In the present invention, the piston member has a lower portion that continuously connects the upper cylindrical portion slidably contacting the outer periphery of the lower end side portion of the cap member to the upper end, and the lower portion extends downward from the lower end side portion of the cap member. The fork main body has a damper in the shaft core portion, and the damper body has a rod body that can be inserted into and retracted from the cylinder body, and the upper end portion of the rod body is By screwing to the shaft core portion of the lower end shaft portion of the cap member, it is possible to assure the lifting and lowering of the piston member in the jack mechanism and to integrally connect the rod body in the damper to the fork main body. Become.

  As a result, there is a front fork that has a jack mechanism that raises and lowers the upper end position of the suspension spring in the fork body, and adjusts the spring force in the suspension spring while ensuring the expansion and contraction operation of the damper in the fork body It is optimal to expect the improvement of versatility.

  Hereinafter, the present invention will be described based on the illustrated embodiment. A front fork according to the present invention is mounted on the front wheel side of a two-wheeled vehicle and suspends the front wheel of the two-wheeled vehicle while inputting road surface vibrations input to the front wheel. Acts as a hydraulic shock absorber.

  In this front fork, as shown in FIG. 1, the upper end position of the suspension spring S accommodated in the fork main body composed of the vehicle body side tube 1 and the wheel side tube 2 is accommodated in the fork main body. It is possible to adjust the spring force of the suspension spring S by moving it up and down by driving the jack mechanism.

  In the figure, the fork body is set to be an inverted type in which the vehicle body side tube 1 is an outer tube and the wheel side tube 2 is an inner tube, but this is not shown in the embodiment of the present invention. However, contrary to the above, the fork main body may be set upright with the vehicle body side tube 1 as the inner tube and the wheel side tube 2 as the outer tube.

  The front fork shown in FIG. 1 will be described briefly. The front fork is configured by housing a suspension spring S, a jack mechanism, and a damper in a fork main body including a vehicle body side tube 1 and a wheel side tube 2.

  In the front fork, the suspension spring S is supported on the cylinder body 3 side of a damper, which will be described later, and the upper end of the suspension spring S via a cylindrical spacer S1. Rather, it is also locked by a jack mechanism, which will be described later, and biases the fork body in the extending direction in the direction in which the wheel side tube 2 protrudes from the vehicle body side tube 1.

  Specifically, the lower end of the suspension spring S is supported on the upper end of an oil lock case 5 provided continuously with the upper end of the cylinder body 3, and the upper end of the spacer S1 that locks the upper end of the suspension spring S is the upper end of the cylinder body 3. The cap member 11 that closes the opening is locked to the lower end of the piston member 12 constituting the jack mechanism.

  The oil lock case 5 is opposed to the oil lock piece 41 held by the rod body 4 of the damper, and the oil lock piece 41 is fitted into the oil lock case 5 when the fork body is fully contracted. In addition to exerting a cushioning effect, an oil lock phenomenon is manifested.

  And a damper is the cylinder body 3 which is a lower end side member standingly arranged in the wheel side tube 2, and the front-end | tip part used as a lower end part in the figure while it is suspended in the vehicle body side tube 1 and is used as an upper end side member. The rod body 4 is inserted into the cylinder body 5 so as to be able to appear and retract.

  Although not shown, the lower end portion of the cylinder body 3 is coupled to a bottom member 21 that closes the lower end opening of the wheel side tube 2, and the upper end portion of the rod body 4 is a cap member 11 that closes the upper end opening of the vehicle body side tube 1. Therefore, the damper is integrally connected to the fork main body and is expanded and contracted in synchronization with the expansion and contraction operation of the fork main body.

  Therefore, in the front fork according to the present invention, the axial direction which is the expansion / contraction direction of the damper coincides with the axial direction which is the expansion / contraction direction of the fork main body, and thus the smooth expansion / contraction operation of the damper with respect to the expansion / contraction fork main body is achieved. It becomes easy to guarantee.

  The damper has a piston part P that is slidably received in the cylinder body 3 while being held at the tip of the rod body 4, and the piston part P is shown in FIG. As shown, the upper body R1 and the lower chamber R2 are defined in the cylinder body 3 so as to be slidably received in the cylinder body 3 while being held by the tip member 43 constituting the tip portion of the rod body 4. It has a piston body 6.

  And in this piston part P, the piston body 6 has the expansion side port 6a and the compression side port 6b, and the expansion side damping valve 6c which obstruct | occludes the downstream end of the ports 6a and 6b of each side so that opening is possible. And a compression side damping valve 6d.

  By the way, the damping valves 6c and 6d on each side are made of annular leaf valves, are arranged in a manner that the outer peripheral end is fixed with the inner peripheral end fixed, and the hydraulic oil passes through the gap appearing there as the outer peripheral end bends. As a result, a predetermined damping action is realized.

  On the other hand, in the above damper, although not shown, the base valve portion is provided in the lower end portion of the cylinder body 3, and the outside of the cylinder body 3 is a reservoir chamber R (see FIG. 1). In addition, the lower chamber R2 in the cylinder body 3 can be communicated via the base valve portion.

  At this time, the base valve portion also has a pressure-side damping valve that allows the hydraulic oil in the lower chamber R2 in the cylinder body 3 to flow out toward the reservoir chamber R, and is parallel to the pressure-side damping valve, although not shown in the figure. Thus, a check valve that allows the hydraulic oil from the reservoir chamber R to flow into the lower chamber R2 in the cylinder body 3 is provided.

  Therefore, in the damper described above, the hydraulic oil in the lower chamber R2 in the cylinder body 3 is transferred to the piston portion P during the contraction operation in which the piston portion P descends in the cylinder body 3 in synchronization with the contraction operation of the fork main body. Flows into the upper chamber R1 through the pressure side damping valve 6d, and an amount of hydraulic oil corresponding to the rod intrusion integral that becomes redundant in the lower chamber R2 flows out into the reservoir chamber R through the pressure side damping valve in the base valve portion. Then, a predetermined compression side damping action is realized.

  In the damper, the hydraulic oil in the upper chamber R1 in the cylinder body 3 is transferred to the piston portion P during the extension operation in which the piston portion P rises in the cylinder body 3 in synchronization with the extension operation of the fork main body. An amount of hydraulic oil corresponding to the rod withdrawal volume that is deficient in the lower chamber R2 is replenished from the reservoir chamber R via the check valve in the base valve portion, while flowing out to the lower chamber R2 via the extension side damping valve 6c. A predetermined extension side damping action is realized.

  Incidentally, when the rod body 4 described above is formed of a pipe body having a through hole 4a in the shaft core portion as shown by a virtual diagram in the drawing, the weight of the rod body 4 can be reduced, This is advantageous in that the section modulus can be increased and the bending strength can be increased.

  Further, even in the above-described tip member 43, as shown by a virtual diagram in the drawing, when the passage 43a is formed of a through hole, in the piston portion P, the passage 43a is used as a bypass passage. A control valve that allows communication between the upper chamber R1 and the lower chamber R2 and that controls the flow rate of hydraulic oil passing through the bypass passage is disposed in the bypass passage, so that the damping valve on each side described above is provided. Thus, the height control of the damping action by 6c and 6d can be made possible.

  At this time, as described above, when the rod body 4 has the through hole 4a of the shaft core portion, the control rod connected to the control valve can be accommodated in the through hole 4a. Thus, the control rod can be driven by an actuator housed in a cap member 11 that closes the upper end opening of the vehicle body side tube 1.

  Incidentally, in the present invention, as described above, the spring force in the suspension spring S accommodated in the fork main body can be adjusted by the jack mechanism. Hereinafter, this jack mechanism will be described a little.

  First, as shown in FIG. 3, the jack mechanism is slidably connected to the lower end side portion 11 a of the cap member 11 that closes the upper end opening of the vehicle body side tube 1 and the lower end side portion 11 a of the cap member 11. It has a piston member 12 that defines a pressure chamber R3 that expands and contracts with the lower end side portion 11a.

  In the jack mechanism, the pressure chamber R3 is expanded by supplying / discharging pressure oil to / from the pressure chamber R3 from a pressure oil supply / discharge source (shown only by reference numeral P1 in the figure) provided outside the fork main body. The piston member 12 is moved up and down with respect to the cap member 11, and the upper end position of the suspension spring S is moved up and down.

  Therefore, the cap member 11 has a through hole 11b in the shaft core portion, and the through hole 11b communicates with the pressure chamber R3 and communicates with a hydraulic pressure supply / discharge source P1 disposed outside the fork main body.

  On the other hand, the cap member 11 includes a lower end shaft portion 11c that protrudes downward from the lower end side portion 11a. The upper end of the rod body 4 is screwed under the presence of the lock nut 42.

  Also from this, as described above, the upper end portion of the rod body 4 is screwed to the cap member 11 which closes the upper end opening of the vehicle body side tube 1 in the damper, so that the cylinder body 3 is connected to the wheel side tube 2. The axial direction as the expansion / contraction direction of the damper coincides with the axial direction as the expansion / contraction direction of the fork body, and therefore the smoothness of the damper with respect to the expanding and contracting for the main body is achieved. The telescopic operation can be ensured.

  Incidentally, a seal 11d is interposed on the outer periphery of the main body portion in the cap member 11 to ensure liquid tightness with the vehicle body side tube 1.

  Meanwhile, the piston member 12 that defines the pressure chamber R3 between the lower end side portion 11a of the cap member 11 has an upper cylindrical portion 12a that is in sliding contact with the outer periphery of the lower end side portion 11a of the cap member 11, and an upper cylindrical portion. The lower part 12b which connects 12a to an upper end is comprised.

  In the piston member 12, the lower portion 12 b protrudes downward from the lower end side portion 11 a of the cap member 11, and the lower end shaft portion for screwing the upper end portion of the rod body 4 to the shaft core portion. In this state, the upper end of the spacer S1 formed in a cylindrical shape is locked via the spring sheet S2 in this state.

  Incidentally, a seal 11e is interposed on the outer periphery of the lower end side portion 11a of the cap member 11 to ensure liquid tightness with the upper cylindrical portion 12a of the piston member 12, and the lower portion of the piston member 12 A seal 12c is interposed on the inner periphery of 12b to ensure liquid-tightness between the cap member 11 and the lower end shaft portion 11c.

  Therefore, in the jack mechanism formed as described above, when the outer diameter of the piston member 12 is set to be smaller than the inner diameter of the wheel side tube 2 formed of the inner tube, Since the wheel side tube 2 entering the vehicle body side tube 1 can be prevented from interfering with the vehicle body side tube 1, it is not necessary to worry that the drive of the jack mechanism is hindered.

  In the jack mechanism, the outer diameter of the upper cylindrical portion 12a of the piston member 12 is made smaller than the inner diameter of the wheel side tube 2, while the lower end side of the cap member 11 that closes the upper end opening of the vehicle body side tube 1 is used. The pressure chamber R3 defined between the cap member 11 and the piston member 12 is slidably contacted with the outer periphery of the portion 11a. Thus, for example, when the inner diameter of the wheel side tube 2 is made the same, the pressure receiving area in the pressure chamber R3 can be increased, and the operating efficiency for the supplied hydraulic pressure can be improved.

  In addition, the jack mechanism is composed of a cap member 11 that closes the upper end opening of the vehicle body side tube 1 and a piston member 12 that is linked to the cap member 11 as compared with the proposal disclosed in Patent Document 1 described above. Therefore, the number of parts can be reduced, and a slight modification to the existing cap member 11 is sufficient.

  In the above description, the pressure chamber R3 in the jack mechanism is connected to the pressure oil supply / discharge source disposed outside the fork main body. However, in view of the function of the jack mechanism according to the present invention, the pressure chamber described above is used. It is not oil that is supplied to and discharged from R3, but water that is an alternative may be used. From the viewpoint of fluid, gas may be used.

  And when water is used, it becomes easy to obtain as a raw material, and when gas is used, there is an advantage that an air spring effect in the pressure chamber R3 can be expected.

  In the above description, the hydraulic shock absorber embodying the present invention is mounted on the front wheel side of the two-wheeled vehicle as a front fork that suspends the front wheel of the two-wheeled vehicle. However, the present invention is intended. Therefore, instead of the above, it may be embodied in a shock absorber that is provided in each part of a four-wheel vehicle and is used as a suspension device.

It is a longitudinal cross-sectional view which shows the front fork by this invention partially fractured | ruptured. FIG. 2 is a partially enlarged longitudinal sectional view showing a piston portion as a damping portion in a damper built in the front fork of FIG. 1. FIG. 2 is a partially enlarged longitudinal sectional view showing an upper end portion of a vehicle body side tube in the front fork of FIG. 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Car body side tube 2 Wheel side tube 3 Cylinder body 4 Rod body 11 Cap member 11a Lower end side part 11b Through-hole 11c Lower end shaft part 12 Piston member 12a Upper cylinder part 12b Lower part P1 Pressure oil supply / discharge source R3 Pressure chamber S Suspension spring S1 spacer

Claims (6)

The upper end position of the suspension spring accommodated in the fork main body composed of the vehicle body side tube and the wheel side tube is moved up and down in the fork main body by driving the jack mechanism of the accommodation to adjust the spring force in the suspension spring. In the front fork, the jack mechanism is slidably connected to the lower end side portion of the cap member that closes the upper end opening of the vehicle body side tube, and the lower end side portion of the cap member. A piston member that defines a pressure chamber that expands and contracts between the pressure member and the pressure chamber is expanded and contracted by supplying and discharging pressure oil to and from the pressure chamber. A front fork characterized by being raised and lowered relative to the upper end position of the suspension spring. The said cap member has a through-hole in an axial center part, This through-hole is connected to the said pressure chamber, and is connected to the hydraulic supply / discharge source arrange | positioned outside the said fork main body. Front fork. The piston member has an upper cylindrical portion that is in sliding contact with the outer periphery of the lower end side portion of the cap member, and the outer diameter of the upper cylindrical portion is set smaller than the inner diameter of the wheel side tube inserted into the vehicle body side tube. The front fork according to claim 1 or 2. The piston member has a lower portion that continuously connects the upper cylindrical portion that is in sliding contact with the outer periphery of the lower end side portion of the cap member, and the lower portion is directed downward from the lower end side portion of the cap member. The front fork according to claim 1, wherein the front fork is formed in sliding contact with the projecting lower end shaft portion. While the suspension spring holds the lower end on the wheel side tube side, the lower end of the cylindrical spacer is brought into contact with the upper end, and the upper end of the spacer is a lower portion where the upper cylindrical portion of the piston member is continuously provided. The front fork according to claim 1, 2, 3, or 4, which is locked at a lower end. The fork main body has a damper in the shaft core portion, and the damper has a rod body that can be inserted into and retracted from the cylinder body. The upper end portion of the rod body extends downward from the lower end side portion of the cap member. 6. The front fork according to claim 1, wherein the front fork is screwed to a shaft core portion of a lower end shaft portion projecting toward the front.

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