Front fork

Abstract

The present invention aims to provide a front fork that can be easily attached to a vehicle body even if it is equipped with a pump for adjusting the ride height. [Solution] A means for solving the aforementioned problems is a cylindrical cap 3 attached to one end opening of the vehicle-side tube 2a of an extendable fork body 2, a pressing body 4 slidably inserted into the cap 3, a spring support 6 that moves axially with the pressing body 4 while supporting the upper end of a suspension spring 5 that biases the fork body 2 in the extension direction, a first seal 7 that seals the space between the pressing body 4 and the cap 3, and an actuator unit 8. The actuator unit 8 includes a housing 9 detachably connected to the cap 3 and having a pressure chamber P, a partition member 10 that is inserted into the pressure chamber P and maintains liquid tightness inside the pressure chamber P while transmitting the pressure of the pressure chamber P to the pressing body 4, and a pump 12 that supplies and discharges liquid to the pressure chamber P.

Description

Technical Field

[0001] The present invention relates to a front fork.

Background Art

[0002] Some front forks that support the front wheels of saddle-riding vehicles are interposed between the vehicle body and the axle of the front wheels in a saddle-riding vehicle to exert damping force. Such a front fork includes a fork body that expands and contracts with a vehicle body side tube connected to the vehicle body of the saddle-riding vehicle and a wheel side tube that fits into the vehicle body side tube and is connected to the axle, a damper cartridge that includes a cylinder and a rod and is housed in the fork body to exert damping force as the fork body expands and contracts, and a suspension spring that biases the damper cartridge and the fork body to extend. It is generally configured to include.

[0003] ​​​​​​​​​​​​​​​​​​​​​​​​

[0006] In this type of front fork, a hose connected to the pump is attached to the cap, but when installing the front fork on a saddle vehicle, the upper end of the tube on the vehicle side needs to be passed through a hole in the upper bracket of the saddle vehicle.

[0007] However, because the pump could not pass through the hole in the upper bracket, installing the front fork to the vehicle required a complicated installation process: first, the hose and pump had to be removed from the vehicle-side tube, then the vehicle-side tube had to be passed through the upper bracket to install the fork body to the vehicle, then the hose connected to the pump had to be connected to the cap, and finally, lubrication had to be applied to the pressure chamber.

[0008] Therefore, the present invention aims to provide a front fork that can be easily attached to a vehicle body even if it is equipped with a pump for adjusting the ride height. [Means for solving the problem]

[0009] To achieve the above objectives, the front fork of the present invention comprises a retractable fork body having a vehicle body side tube and a wheel side tube, a cylindrical cap attached to one end opening of the vehicle body side tube, a pressing body slidably inserted into the cap in the axial direction, a spring receiver that moves axially with the pressing body while supporting the cap side end of a suspension spring housed in the fork body and biasing the fork body in the extension direction, a first seal that seals the space between the pressing body and the cap, and an actuator unit that can drive the spring receiver axially relative to the cap via the pressing body, wherein the actuator unit comprises a housing detachably connected to the cap and having a pressure chamber, a partition member that keeps the pressure chamber liquid-tight when inserted into the pressure chamber and can transmit the pressure of the pressure chamber to the pressing body, and a pump that supplies and discharges liquid to the pressure chamber. In this configuration, the fork body is sealed and kept liquid-tight by the first seal, and the pressure chamber of the actuator unit is kept liquid-tight by the partition member. Therefore, the actuator unit can be separated from the fork body without risk of leakage, even if liquid is still being lubricated in the pressure chamber. In this way, both the fork body and the actuator unit can be separated while maintaining liquid tightness. As a result, the installation of the front fork to the vehicle body is completed simply by attaching the fork body to the vehicle body and then connecting the actuator unit to the cap of the fork body. Thus, with the front fork of the present invention, the front fork can be easily installed on the vehicle body without the need for complicated procedures such as lubricating the pressure chamber after installation.

[0010] Furthermore, in the front fork of the present invention, the partition member may have a second seal that seals the pressure chamber. With this configuration, the pressure chamber is sealed and kept liquid-tight by the second seal.

[0011] Furthermore, in the front fork of the present invention, the inner circumference of the cap is provided with a cylindrical insertion portion into which a cylindrical pressing body is inserted, and a cylindrical mounting portion which has a larger diameter than the insertion portion into which the housing is inserted. The housing has a cylindrical portion which is inserted into the mounting portion, and a bottom portion which closes the end of the cylindrical portion on the side of the pressing body and has a through hole which faces the pressing body in the axial direction. The partition member has a disc-shaped piston which is movable in the axial direction while sliding against the inner circumference of the cylindrical portion, and an output shaft which protrudes from the bottom end of the piston and is inserted into the through hole while contacting the pressing body. The axial length of the output shaft is set to the length to which the end of the output shaft protrudes from the bottom when the piston is furthest from the bottom, and the axial length of the pressing body may be set to the length to which the end of the pressing body protrudes from the insertion portion toward the mounting portion when the spring receiver is at its uppermost position. With this configuration, when the actuator unit and the fork body are separated, the end of the pressing body protrudes from the insertion portion of the cap, and the end of the output shaft protrudes from the bottom of the housing. Therefore, if the front fork is in a normal state, the pressing element and output shaft can be seen from the outside with the actuator unit and fork body separated. As a result, it is easy to check whether there are any problems with the assembly of the actuator unit or the assembly of the pressing element to the cap by checking whether the pressing element and output shaft can be seen from the outside, making it easier to detect problems with the front fork.

[0012] Furthermore, in the front fork of the present invention, the partition member is a disc-shaped piston that can move axially while sliding against the inner circumference of the housing, and the end of the pressing body may abut against the piston within the housing. With this configuration, the shape of the partition member is a simple disc shape, which reduces processing costs.

[0013] Furthermore, in the front fork of the present invention, the partition member is movable axially within the housing, and the actuator unit may be provided with a stroke sensor for detecting the stroke position of the partition member. With this configuration, since the stroke sensor is provided on the actuator unit side which is separable from the fork body, the installation of the stroke sensor becomes easier. Also, in the event of a stroke sensor failure, the actuator unit can be separated, making it easy to replace or repair the stroke sensor provided on the actuator unit. [Effects of the Invention]

[0014] According to the front fork of the present invention, it can be easily attached to the vehicle body even if it is equipped with a pump for adjusting the ride height. [Brief explanation of the drawing]

[0015] [Figure 1] Figure 1 is a side view of a saddle vehicle equipped with a front fork according to an embodiment of the present invention. [Figure 2] Figure 2 is a longitudinal cross-sectional view of the front fork in an embodiment of the present invention. [Figure 3] Figure 3 is an enlarged longitudinal cross-sectional view of the upper end of the front fork in an embodiment of the present invention, showing the state in which the support position of the upper end of the suspension spring is at its lowest position. [Figure 4] Figure 4 is an enlarged longitudinal cross-sectional view of the upper end of the front fork in an embodiment of the present invention, showing the state in which the support position of the upper end of the suspension spring is at its highest point. [Figure 5] Figure 5 is an enlarged longitudinal cross-sectional view of the upper end of the front fork in a first modified embodiment of the present invention. [Figure 6] Figure 6 is an enlarged longitudinal cross-sectional view of the upper end of the front fork in a second modified embodiment of the present invention. [Modes for carrying out the invention]

[0016] Hereinafter, based on the embodiments shown in the drawings, the front fork 1 of the present invention will be described. The same reference numerals attached through several drawings indicate the same parts. As shown in FIG. 1, the front fork 1 of the present embodiment is interposed and attached between the vehicle body B and the wheel W of the saddle-riding vehicle V. Also, the up and down in the state where the front fork 1 is attached to the saddle-riding vehicle V are simply referred to as "up" and "down" unless otherwise specified.

[0017] As shown in FIGS. 2, 3, and 4, the front fork 1 of the present invention includes a fork main body 2 having a vehicle body side tube 2a and a wheel side tube 2b and being telescopic, a cylindrical cap 3 attached to one end side opening of the vehicle body side tube 2a, a pressing body 4 slidably inserted in the axial direction in the cap 3, a spring receiver 6 that supports the upper end, which is the cap side end of the suspension spring 5 housed in the fork main body 2 and biases the fork main body 2 in the extending direction, and moves axially together with the pressing body 4, a first seal 7 that seals between the pressing body 4 and the cap 3, and an actuator unit 8 that can drive the spring receiver 6 axially with respect to the cap 3 via the pressing body 4. The actuator unit 8 includes a housing 9 that is detachable from the cap 3 and has a pressure chamber P, a partition member 10 that is inserted into the pressure chamber P and keeps the inside of the pressure chamber P liquid-tight and can transmit the pressure of the pressure chamber P to the pressing body 4, and a pump 12 that supplies and discharges liquid to and from the pressure chamber P.

[0018] Hereinafter, each part of the front fork 1 will be described. As shown in FIG. 2, the fork main body 2 has a vehicle body side tube 2a and a wheel side tube 2b, and is biased in the extending direction by a suspension spring 5 housed therein, and includes a damper cartridge 13 that expands and contracts along with the expansion and contraction of the fork main body 2 and exhibits a damping force.

[0019] As shown in Figure 1, the vehicle body tube 2a is inserted into holes (not shown) in the upper bracket BR1 and lower bracket BR2 provided on the vehicle body B of the saddle vehicle V, and is gripped by bolts (not shown) to connect it to the vehicle body B. The wheel side tube 2b has a smaller diameter than the vehicle body tube 2a and is inserted into the vehicle body tube 2a from below. The fork body 2 expands and contracts when the vehicle body tube 2a and the wheel side tube 2b move relative to each other in the axial direction. The upper end opening of the vehicle body tube 2a is closed by a cap 3, and the lower end of the wheel side tube 2b is closed by an axle bracket 14 that grips the axle Wa of the wheel W of the saddle vehicle V. Furthermore, as shown in Figure 2, annular bearings 15 and 16 are provided between the vehicle body tube 2a and the wheel side tube 2b, allowing the vehicle body tube 2a and the wheel side tube 2b to move smoothly in the axial direction. Furthermore, an annular sealing member 17 is provided on the inner circumference of the lower end of the vehicle body side tube 2a, which slides against the outer circumference of the wheel side tube 2b, thereby sealing the internal space of the fork body 2.

[0020] Therefore, in this embodiment, the front fork 1 suspends the wheel W and elastically supports the body B of the saddled vehicle V, reducing vibration input from the wheel side to the body B and suppressing vibration of the body B through the damping force exerted by the damper cartridge 13. In this embodiment, the front fork 1 is of the so-called inverted type, in which the wheel-side tube 2b is inserted into the body-side tube 2a from below. However, it may also be of the so-called upright type, in which the body-side tube 2a has a smaller diameter than the wheel-side tube 2b and the body-side tube 2a is inserted into the wheel-side tube 2b.

[0021] The damper cartridge 13 expands and contracts along with the expansion and contraction of the fork body 2 to exert a damping force. The damper cartridge 13 includes a cylinder 13a fixed to an axle bracket 14 that closes the lower end opening of the wheel side tube 2b, a piston 13b that is slidably inserted into the cylinder 13a and partitions the cylinder 13a into an extension chamber R1 and a compression chamber R2 filled with liquid, and a piston rod 13c that is connected to the piston 13b and is inserted into the cylinder 13a so as to be axially movable and is connected to a cap 3 that closes the upper end opening of the vehicle body side tube 2a. Further, an annular gap formed between the damper cartridge 13 and the wheel side tube 2b is used as a reservoir R filled with liquid and gas. Although not shown, between the reservoir R and the compression chamber R2, a suction passage that allows only the passage of liquid from the reservoir R to the compression chamber R2 and a damping passage provided with a base valve that allows only the passage of liquid from the compression chamber R2 to the reservoir R and gives resistance to the flow of the passing liquid are provided. Therefore, the volume of liquid that the piston rod 13c entering and leaving the cylinder 13a during expansion and contraction pushes back in the cylinder 13a can be exchanged between the cylinder 13a and the reservoir R through the suction passage and the damping passage so that volume compensation can be achieved. Note that as the liquid, in addition to hydraulic oil, any liquid that can exert a damping force can be used.

[0022] Furthermore, the piston 13b is annular and has an extension port 13b1 and a compression port 13b2 that connect the extension chamber R1 and the compression chamber R2. An annular extension leaf valve 13d that opens and closes the extension port 13b1 is mounted on the lower end of the piston 13b in Figure 2, and an annular compression check valve 13e that opens and closes the compression port 13b2 is mounted on the upper end of the piston 13b in Figure 2. These piston 13b, extension leaf valve 13d, and compression check valve 13e are all mounted on the outer circumference of a piston connecting member 13f that is connected to the lower end of the piston rod 13c in Figure 2. The inner circumference of the extension leaf valve 13d is fixed to the piston rod 13c, and when the outer circumference flexes and separates from the piston 13b, it opens the corresponding extension port 13b1. Furthermore, the compression check valve 13e is slidably mounted on the inner circumference of the piston rod 13c and is pressed against the piston 13b by a spring 13g, thereby closing the extension port 13b1.

[0023] Furthermore, a cylindrical rod guide 13h is mounted on the inner circumference of the upper end of the cylinder 13a, into which the piston rod 13c is slidably inserted. In addition to guiding the axial movement of the piston rod 13c, the rod guide 13h functions as a spring support that supports the lower end of the suspension spring 5, and also functions as an oil lock case that prevents further contraction of the damper cartridge 13 and the fork body 2 by allowing the oil lock piece 13i, which is provided on the outer circumference of the piston rod 13c, to enter.

[0024] In this configuration, when the fork body 2 extends, the damper cartridge 13 also extends, and the extension chamber R1 is compressed by the piston 13b. When the pressure in the extension chamber R1 reaches the opening pressure of the extension leaf valve 13d, the liquid in the extension chamber R1 moves to the compression chamber R2 through the extension port 13b1. The extension leaf valve 13d resists this liquid flow, creating a pressure difference between the extension chamber R1 and the compression chamber R2, causing the front fork 1 to exert a damping force that suppresses extension. Additionally, when the damper cartridge 13 extends, the liquid equivalent to the volume released from the cylinder 13a by the piston rod 13c flows from the reservoir R into the compression chamber R2 via the suction passage, thus compensating for the volume.

[0025] Furthermore, when the fork body 2 contracts, the damper cartridge 13 also contracts, and the compression chamber R2 is compressed by the piston 13b. As a result, the pressure in the compression chamber R2 opens the compression check valve 13e, causing the liquid in the compression chamber R2 to move to the extension chamber R1 through the compression port 13b2, while the liquid equivalent to the volume of the piston rod 13c entering the cylinder 13a is discharged from the compression chamber R2 to the reservoir R via the damping passage. The base valve provided in the damping passage resists this flow of liquid discharged from the compression chamber R2 to the reservoir R, creating a pressure difference between the compression chamber R2 and the extension chamber R1, and causing the front fork 1 to exert a damping force that suppresses the contraction operation.

[0026] The configuration of the damper cartridge 13 described above is merely an example, and the configuration of the damper cartridge 13 is not particularly limited as long as it extends and contracts in conjunction with the extension and contraction of the fork body 2 and exerts damping force.

[0027] Next, as shown in Figures 2, 3, and 4, the cap 3 is cylindrical and includes a connecting portion 3a that is screwed to the upper end opening of the vehicle body side tube 2a, an intermediate portion 3b connected to the lower end of the connecting portion 3a and having a smaller outer diameter than the connecting portion 3a, a guide portion 3c connected to the lower end of the intermediate portion 3b and having a smaller outer diameter than the intermediate portion 3b and having a pair of rectangular openings 3c1, 3c1 facing each other on the side with a 180-degree phase difference, and a rod connecting portion 3d connected to the lower end of the guide portion 3c and having a diameter that is gradually reduced in diameter from the guide portion 3c.

[0028] A screw groove is formed on the inner circumference of the rod connecting portion 3d, and a screw groove provided on the outer circumference of the upper end of the piston rod 13c is screw-connected to this screw groove. In this way, the upper end of the piston rod 13c is screw-fastened to the rod connecting portion 3d of the cap 3. Furthermore, a nut 19 is screwed into the screw groove on the outer circumference of the upper end of the piston rod 13c and abuts against the lower end of the rod connecting portion 3d, so that the rod connecting portion 3d and the nut 19 tighten against each other, preventing loosening and making the fastening between the cap 3 and the piston rod 13c firm.

[0029] The connecting portion 3a is equipped with a threaded portion 3a1 on its outer circumference. The connecting portion 3a is connected to the vehicle body side tube 2a by screwing the threaded portion 3a1 on its outer circumference to the threaded portion 2a1 formed on the inner circumference of the upper end opening of the vehicle body side tube 2a. In addition, a seal ring 20 is fitted on the outer circumference of the connecting portion 3a above the threaded portion 3a1, which is in close contact with the inner circumference of the vehicle body side tube 2a, thereby sealing the space between the cap 3 and the vehicle body side tube 2a.

[0030] The intermediate portion 3b is cylindrical in shape, with an outer diameter smaller than the outer diameter of the connecting portion 3a and an inner diameter smaller than the connecting portion 3a. An annular groove 3b2 is formed at the upper end 3b1 facing the inside of the cap 3.

[0031] The spring support 6 comprises a cylindrical spring support body 6a that is slidably mounted on the outer circumference of the guide portion 3c of the cap 3 and supports the upper end of the suspension spring 5 at its lower end, and a restricting portion 6b that is stacked on the upper end of the spring support body 6a.

[0032] The restricting portion 6b comprises an annular disc portion 6b1 inserted into the guide portion 3c, and two arm portions 6b2, 6b2 provided on the outer circumference of the disc portion 6b1 with a 180-degree phase difference, the tips of which protrude outside the guide portion 3c through an opening 3c1 provided on the side of the guide portion 3c, and the restricting portion 6b is movable up and down relative to the guide portion 3c. Therefore, the spring receiver 6 is movable up and down relative to the cap 3 within the range in which the arm portions 6b2 of the restricting portion 6b can move up and down within the opening 3c1.

[0033] Furthermore, the regulating portion 6b is connected to a pressing body 4 that is slidably inserted into the inner circumference of the intermediate portion 3b of the cap 3. Specifically, the pressing body 4 is slidably inserted into the intermediate portion 3b of the cap 3, with the intermediate portion 3b serving as the insertion portion. The pressing body 4 is cylindrical and is inserted through the inner circumference of the disc portion 6b1 of the regulating portion 6b, thereby connecting it to the regulating portion 6b. In addition, an annular first seal 7 is attached to the outer circumference of the pressing body 4 to seal the space between it and the inner circumference of the intermediate portion 3b. This ensures that the inside of the fork body 2 is sealed.

[0034] Furthermore, the axial length of the pressing body 4 is set such that, as shown in Figure 4, when the spring receiver 6 is in its uppermost position (when the arm portion 6b2 of the restricting portion 6b in the spring receiver 6 is located as far upward as possible within the opening 3c1 of the guide portion 3c in the cap 3), the end of the pressing body 4 protrudes upward from the intermediate portion 3b.

[0035] In this embodiment, the restricting portion 6b is connected to the pressing body 4 by inserting the small-diameter portion 4a, which is provided at the lower end of the cylindrical pressing body 4, into the inside of the disc portion 6b1 of the restricting portion 6b, and then fitting the C-pin 4b onto the outer circumference of the portion of the small-diameter portion 4a that protrudes from the lower end of the disc portion 6b1. However, the method of connecting the restricting portion 6b and the pressing body 4 is not particularly limited. Also, the restricting portion 6b and the pressing body 4 may be formed integrally as long as the fork body 2 can be assembled.

[0036] Next, the actuator unit 8 will be described in detail. The actuator unit 8 includes a housing 9 that is removable from the cap 3 and has a pressure chamber P, a partition member 10 that is inserted into the pressure chamber P and maintains a liquid-tight seal inside the pressure chamber P and can transmit the pressure of the pressure chamber P to the pressing body 4, and a pump 12 that supplies and discharges liquid to the pressure chamber P.

[0037] More specifically, the housing 9 comprises a cylindrical portion 9a inserted into the connecting portion 3a, which serves as the mounting portion of the cap 3, and a bottom portion 9b that closes the lower end of the cylindrical portion 9a, which is the end on the pressing body side, and has a through hole 9b1 that faces axially opposite the upper end of the pressing body 4 in Figure 2. The bottom portion 9b is also provided with a plurality of communication holes 9b2 arranged circumferentially outside the through hole 9b1, and the communication holes 9b2 communicate axially opposite to an annular groove 3b2 provided at the upper end 3b1 of the intermediate portion 3b of the cap 3. Furthermore, an annular seal ring 9b3 is provided on the outer circumference of the bottom portion 9b, sealing the space between the connecting portion 3a and the bottom portion 9b.

[0038] Furthermore, an annular flange portion 9c is provided on the outer circumference near the axial center of the cylindrical portion 9a of the housing 9. Multiple holes 9c1 are formed in the flange portion 9c, which are arranged in the circumferential direction, and multiple bolt holes 3e are formed at the upper end of the cap 3, which are arranged at the same intervals as the holes 9c1 in the circumferential direction. The cylindrical portion 9a is inserted into the connecting portion 3a, and with the flange portion 9c in contact with the upper end of the cap 3 so that the holes 9c1 face the bolt holes 3e in the axial direction, the bolts 21 are screwed into the bolt holes 3e through the holes 9c1, thereby clamping the flange portion 9c between the heads of the bolts 21 and the upper end of the cap 3. In this way, the housing 9 is connected while inserted into the cap 3. Since the housing 9 is connected to the cap 3 by bolts 21, the housing 9 can be separated from the cap 3 by removing the bolts 21. Therefore, the housing 9 is detachably connected to the cap 3. However, the method of connecting the housing 9 to the cap 3 is not particularly limited as long as it is detachable from the cap 3, and methods other than bolt fastening may be used.

[0039] The partition member 10 has a disc-shaped piston 10a that is movable in the axial direction while sliding against the inner circumference of the cylindrical portion 9a and partitions a pressure chamber P within the housing 9, an output shaft 10b that protrudes from the lower end of the piston 10a (the bottom end in the housing 9) and is inserted into the through hole 9b1 while contacting the upper end of the pressing body 4, and a second seal 10c provided on the outer circumference of the piston 10a to seal the pressure chamber P. The output shaft 10b is slidably inserted into the through hole 9b1 and its axial movement relative to the housing 9 is guided. Since the piston 10a and the output shaft 10b are in sliding contact with the inner circumference of the housing 9, the partition member 10 can move in the axial direction without axial wobble, but the output shaft 10b does not necessarily need to be guided by the bottom 9b. Furthermore, the second seal 10c is fitted into an annular groove (not shown) provided on the outer circumference of the piston 10a and slides against the inner circumference of the cylindrical portion 9a, sealing the space between the piston 10a and the cylindrical portion 9a. The void G formed below the piston 10a inside the housing 9 is in communication with the annular groove 3b2 via a communication hole 9b2 in the bottom portion 9b of the housing 9.

[0040] Furthermore, an annular lid member 22 is fitted to the inner circumference of the upper end of the cylindrical portion 9a of the housing 9. A threaded portion 22a is provided on the inner circumference of the lid member 22, and one end of a hose (not shown) is connected to the inner circumference of the lid member 22 by screw fastening. A pump 12 is connected to the other end of the hose (not shown), and liquid can be supplied to and discharged from the pressure chamber P by driving the pump 12. Although not shown, a sealing member is also provided between the hose and the lid member 22. In addition, a sealing ring 22b is fitted to the outer circumference of the lid member 22, sliding against the inner circumference of the cylindrical portion 9a of the housing 9 to seal the space between the lid member 22 and the cylindrical portion 9a. The pressure chamber P is kept liquid-tight by a second seal 10c connected to the pump 12, which seals the space between the piston 10a and the cylindrical portion 9a.

[0041] The shape of the hose and the method of attaching the hose to the housing 9 are not particularly limited. Similarly, the type of pump 12 is not particularly limited, as long as it can supply and discharge liquid to and from the pressure chamber P. In this embodiment, the liquid supplied by the pump 12 is hydraulic oil, but other liquids such as water or aqueous solutions can also be used.

[0042] As described above, in this embodiment, the fork body 2 is sealed and kept liquid-tight by the first seal 7, and the pressure chamber P of the actuator unit 8 is kept liquid-tight by the partition member 10. Therefore, the actuator unit 8 can be separated from the fork body 2 without risk of liquid leakage, even if liquid remains in the pressure chamber P.

[0043] In this way, since both the fork body 2 and the actuator unit 8 can be separated while maintaining liquid-tightness, the front fork 1 can be installed between the vehicle body B and the wheel W of the saddle vehicle V by inserting the vehicle body side tube 2a of the fork body 2 into the holes of the upper bracket BR1 and the lower bracket BR2 from below, gripping the fork body 2 with the upper bracket BR1 and the lower bracket BR2 and attaching it to the vehicle body B, and then connecting the actuator unit 8 to the cap 3 of the fork body 2. In this way, the installation of the front fork 1 to the vehicle body B is completed simply by attaching the fork body 2 to the vehicle body B and then connecting the actuator unit 8, which already has liquid lubricated in the pressure chamber P, to the cap 3 of the fork body 2. This eliminates the need for the complicated procedure of lubricating the pressure chamber P after the front fork 1 has been installed, making it easy to install the front fork 1 to the vehicle body B.

[0044] Next, the method of adjusting the vehicle height using the front fork 1 of this embodiment will be described in detail. First, to raise the vehicle height, the pump 12 is driven to supply liquid into the pressure chamber P. As shown in Figure 3, the partition member 10, whose output shaft 10b is in contact with the upper end of the pressing body 4, is pressed by the liquid supplied into the pressure chamber P and moves downward against the biasing force of the suspension spring 5 acting via the pressing body 4 and spring receiver 6 and the pressure of the air gap G. When the partition member 10 moves downward, the pressing body 4 and spring receiver 6 also move downward, pushed by the partition member 10, and the fork body 2 extends by the amount that the support position of the upper end of the suspension spring 5 moves downward, raising the vehicle height.

[0045] Conversely, to lower the vehicle height, the pump 12 is driven in the reverse direction to discharge the liquid in the pressure chamber P. As a result, the bulkhead member 10 is pushed upward and moves upward due to the biasing force of the suspension spring 5 acting via the pressing body 4 and spring receiver 6, and the pressure of the air gap G, as shown in Figure 4. When the bulkhead member 10 moves upward, the pressing body 4 and spring receiver 6 also move upward, and the fork body 2 contracts by the amount that the support position of the upper end of the suspension spring 5 has moved upward, lowering the vehicle height.

[0046] In other words, in the front fork 1 of this embodiment, the vehicle height can be adjusted by the bulkhead member 10 moving up and down inside the housing 9, causing the actuator unit 8 to extend and retract.

[0047] Since both the bulkhead member 10 and the spring receiver 6 move vertically, the vertical stroke range of the bulkhead member 10 is the same as that of the spring receiver 6, which is the range in which the arm portion 6b2 of the restricting portion 6b can move vertically within the opening 3c1.

[0048] Furthermore, as mentioned above, in this embodiment, the gap G formed below the piston 10a in the housing 9 is connected to the annular groove 3b2 of the cap 3. This prevents the pressure in the gap G from becoming high when the partition member 10 strokes toward the extension side (downward in the figure), allowing the partition member 10 to move smoothly and making it easy to adjust the vehicle height. However, if the pressure in the gap G does not hinder the smooth movement of the partition member 10 when the partition member 10 strokes toward the extension side, the annular groove 3b2 and the connecting hole 9b2 may be omitted.

[0049] Furthermore, in the case of the front fork 1 of this embodiment, where the vehicle height is adjusted by supplying and discharging liquid to the pressure chamber P using a pump 12, the higher the discharge capacity of the pump 12, the shorter the time required for vehicle height adjustment and the wider the range of adjustable vehicle height. However, a pump 12 with a high discharge capacity requires a larger motor to drive the pump 12, resulting in a larger overall size.

[0050] In contrast, as mentioned above, in this embodiment, the actuator unit 8 can be separated from the fork body 2 without the risk of fluid leakage. Therefore, the fork body 2 can be attached to the vehicle body B by inserting the vehicle body side tube 2a of the fork body 2 into the holes of the upper bracket BR1 and the lower bracket BR2 from below, and then the actuator unit 8 equipped with the pump 12 can be connected to the cap 3 of the fork body 2. Thus, since it is not necessary to pass the pump 12 through the holes of the upper bracket BR1 and the lower bracket BR2, it is not a problem even if the size of the pump 12 is larger than the size of the holes in the upper bracket BR1 and the lower bracket BR2. Therefore, in this embodiment, the front fork 1 can be fitted with a pump of any size, regardless of the size of the holes in the upper bracket BR1 and the lower bracket BR2.

[0051] Furthermore, in this embodiment, the axial length of the pressing body 4 is set to the length that protrudes from the middle portion 3b of the cap 3 toward the connecting portion 3a when the spring receiver 6 is at its uppermost position, as shown in Figure 4. In addition, the axial length of the output shaft 10b of the partition member 10 is set to the length that the end of the output shaft 10b protrudes downward from the bottom 9b when the piston 10a is furthest from the bottom 9b of the housing 9 (when the upper end of the piston 10a is in contact with the lower end of the cover member 22), as shown in Figure 4. Therefore, when the actuator unit 8 and the fork body 2 are separated, the end of the pressing body 4 protrudes from the middle portion 3b of the cap 3, and the end of the output shaft 10b protrudes slightly from the bottom 9b of the housing 9. Thus, when the front fork 1 is in a normal state, the pressing body 4 and the output shaft 10b can be seen from the outside when the actuator unit 8 and the fork body 2 are separated. Therefore, by checking whether the pressing body 4 and output shaft 10b can be seen from the outside, it is easy to confirm whether there are any problems with the assembly of the actuator unit 8 or the assembly of the pressing body 4 to the cap 3, making it easier to detect problems with the front fork 1.

[0052] The protrusion lengths of the pressing body 4 from the middle portion 3b of the cap 3 and the protrusion length of the output shaft 10b from the bottom portion 9b of the housing 9 can be determined arbitrarily, but as long as they are visible from the outside, a length that protrudes even slightly is sufficient. However, the pressing body 4 and the output shaft 10b do not necessarily have to protrude from the middle portion 3b of the cap 3 and the bottom portion 9b of the housing 9, respectively.

[0053] Furthermore, in this embodiment, the actuator unit 8 is detachably connected to the cap 3 of the fork body 2 by connecting the housing 9 to the cap 3 with bolts 21. However, the method of connecting the housing 9 to the cap 3 is not limited to bolts 21, as long as it is detachable from the cap 3. For example, threaded parts may be provided on the inner circumference of the connecting part 3a of the cap 3 and on the outer circumference of the cylindrical part 9a of the housing 9, and the housing 9 may be screwed into the inner circumference of the connecting part 3a to fasten the housing 9 to the cap 3. However, when the housing 9 is connected to the cap 3 with bolts 21, the housing 9 does not rotate relative to the cap 3. Therefore, for example, if a hose (not shown) connected to the housing 9 via a lid member 22 is L-shaped and the orientation of the pump-side end of the hose is predetermined, or if a hose (not shown) is connected to a position radially offset from the center of the cap 3 and the circumferential connection position of the hose to the cap 3 is predetermined, connecting the housing 9 to the cap 3 with bolts 21 will not change the orientation of the pump-side end of the hose or the circumferential connection position to the cap 3.

[0054] As described above, the front fork 1 of this embodiment comprises a retractable fork body 2 having a vehicle body side tube 2a and a wheel side tube 2b, a cylindrical cap 3 attached to the opening at one end of the vehicle body side tube 2a, a pressing body 4 inserted into the cap 3 so as to be slidable in the axial direction, a spring receiver 6 that moves axially with the pressing body 4 while supporting the upper end, which is the cap side end of a suspension spring 5 housed in the fork body 2 and biasing the fork body 2 in the extension direction, a first seal 7 that seals the space between the pressing body 4 and the cap 3, and an actuator unit 8 that can drive the spring receiver 6 axially relative to the cap 3 via the pressing body 4. The actuator unit 8 comprises a housing 9 that is detachably connected to the cap 3 and has a pressure chamber P, a partition member 10 that is inserted into the pressure chamber P and can maintain liquid tightness inside the pressure chamber P and transmit the pressure of the pressure chamber P to the pressing body 4, and a pump 12 that supplies and discharges liquid to the pressure chamber P.

[0055] With the front fork 1 configured in this way, the fork body 2 is sealed and kept liquid-tight by the first seal 7, and the pressure chamber P of the actuator unit 8 is kept liquid-tight by the partition member 10. Therefore, the actuator unit 8 can be separated from the fork body 2 without the risk of liquid leakage, even if liquid is still being lubricated in the pressure chamber P. In this way, both the fork body 2 and the actuator unit 8 can be separated while maintaining liquid tightness. Thus, the installation of the front fork 1 to the vehicle body B is completed simply by attaching the fork body 2 to the vehicle body B and then connecting the actuator unit 8 to the cap 3 of the fork body 2. Therefore, with the front fork 1 of this embodiment, the front fork 1 can be easily installed on the vehicle body B without the need for complicated procedures such as lubricating the pressure chamber P after installation.

[0056] Furthermore, in the front fork 1 of this embodiment, the vehicle-side tube 2a of the fork body 2 is inserted from below into the holes of the upper bracket BR1 and the lower bracket BR2 to attach it to the vehicle body B, and then the actuator unit 8 equipped with a pump 12 is connected to the cap 3 of the fork body 2. Therefore, it is not necessary to pass the pump 12 through the holes of the upper bracket BR1 and the lower bracket BR2. Consequently, a pump 12 of any size can be selected regardless of the size of the holes in the upper bracket BR1 and the lower bracket BR2. Thus, in the front fork 1 of this embodiment, a large pump 12 with high discharge capacity can be used to shorten the time required for vehicle height adjustment and to increase the range of adjustable vehicle height.

[0057] Furthermore, in the front fork 1 configured in this way, the pressure in the pressure chamber P is transmitted to the pressing body 4 via the bulkhead member 10. When the pump 12 is driven and liquid is supplied to the pressure chamber P, the bulkhead member 10 is pressed by the liquid supplied to the pressure chamber P and moves downward. As a result, the pressing body 4 is pushed downward in the axial direction via the bulkhead member 10, so the spring receiver 6 also moves downward together with the pressing body 4, and the fork body 2 extends by the amount that the support position of the upper end of the suspension spring 5 moves downward, increasing the vehicle height. Conversely, when the pump 12 is driven in the reverse direction and liquid is discharged from the pressure chamber P, the bulkhead member 10 is pressed upward by the biasing force of the suspension spring 5 acting via the pressing body 4 and moves upward. When the bulkhead member 10 moves upward, the pressing body 4 and the spring receiver 6 also move upward, and the fork body 2 contracts by the amount that the support position of the upper end of the suspension spring 5 moves upward, lowering the vehicle height. In other words, in the front fork 1 of this embodiment, the pressure in the pressure chamber P is transmitted to the pressing body 4 via the bulkhead member 10, so when liquid is supplied to and discharged from the pressure chamber P by the pump 12, the spring receiver 6 moves up and down together with the pressing body 4, allowing the vehicle height to be adjusted.

[0058] In this embodiment, the first seal 7 is provided on the outer circumference of the pressing body 4, but the first seal 7 may also be provided on the cap 3 side.

[0059] Furthermore, in this embodiment, the partition member 10 transmits the pressure of the pressure chamber P to the pressing body 4 by directly contacting it. However, another member may be interposed between the partition member 10 and the pressing body 4 so that the partition member 10 indirectly contacts the pressing body 4.

[0060] Furthermore, in the front fork 1 of this embodiment, the partition member 10 has a second seal 10c that seals the pressure chamber P. With this configuration, the pressure chamber P is sealed by the second seal 10c and kept liquid-tight. In this embodiment, the second seal 10c is provided on the outer circumference of the partition member 10, but it may also be provided on the housing 9 side. In addition, instead of the structure with the piston 10a described above, the partition member 10 may be an elastic partition such as a bladder, diaphragm, or bellows, as long as it can transmit the pressure of the pressure chamber P to the pressing body 4 via the partition member. In that case, the second seal 10c can be omitted.

[0061] Furthermore, in the front fork 1 of this embodiment, the inner circumference of the cap 3 is provided with a cylindrical intermediate portion 3b (insertion portion) into which a cylindrical pressing body 4 is inserted, and a cylindrical connecting portion 3a (mounting portion) which has a larger diameter than the intermediate portion 3b into which the housing 9 is inserted. The housing 9 has a cylindrical portion 9a that is inserted into the connecting portion 3a, and a bottom portion 9b which closes the pressing body side end of the cylindrical portion 9a and has a through hole 9b1 that faces the pressing body 4 in the axial direction. The partition member 10 slides against the inner circumference of the cylindrical portion 9a in the axial direction. The device has a disc-shaped piston 10a that is movable in the direction, and an output shaft 10b that protrudes from the bottom end of the piston 10a and is inserted into a through hole 9b1 while contacting the pressing body 4. The axial length of the output shaft 10b is set to the length at which the end of the output shaft 10b protrudes from the bottom 9b when the piston 10a is furthest from the bottom 9b, and the axial length of the pressing body 4 is set to the length at which the end of the pressing body 4 protrudes from the intermediate part 3b (insertion part) toward the connecting part 3a (mounting part) when the spring receiver 6 is at its uppermost position.

[0062] With the front fork 1 configured in this way, when the actuator unit 8 and the fork body 2 are separated, the end of the pressing body 4 protrudes from the middle part 3b (insertion part) of the cap 3, and the end of the output shaft 10b protrudes from the bottom part 9b of the housing 9. Therefore, if the front fork 1 is in a normal state, the pressing body 4 and the output shaft 10b can be seen from the outside when the actuator unit 8 and the fork body 2 are separated. As a result, it is easy to check whether there are any problems with the assembly of the actuator unit 8 or the assembly of the pressing body 4 to the cap 3 by checking whether the pressing body 4 and the output shaft 10b can be seen from the outside, making it easier to detect problems with the front fork 1. However, if the front fork 1 is only to perform a ride height adjustment function, the pressing body 4 and the output shaft 10b do not need to protrude from the middle part 3b (insertion part) of the cap 3 and the bottom part 9b of the housing 9, respectively. In addition, in this embodiment, the pressing body 4 is formed in a cylindrical shape, but the shape of the pressing body 4 is not particularly limited.

[0063] Furthermore, in the front fork 1 of this embodiment, the partition member 10 is composed of a disc-shaped piston 10a and an output shaft 10b that protrudes from the lower end of the piston 10a and abuts against the pressing body 4. However, as shown in Figure 5, the partition member 10A may be composed only of a disc-shaped piston 10a that is movable in the axial direction while sliding against the inner circumference of the cylindrical portion 9a of the housing 9, and the axial length of the pressing body 4 may be increased so that the end of the pressing body 4 abuts against the piston 10a inside the housing 9.

[0064] Even with this configuration, the end of the pressing body 4 is in contact with the lower end of the piston 10a that constitutes the partition wall member 10A, so that the pressure in the pressure chamber P is transmitted to the pressing body 4 via the partition wall member 10A. Therefore, when liquid is supplied to and discharged from the pressure chamber P by the pump 12, the spring receiver 6 moves up and down together with the pressing body 4, allowing the vehicle height to be adjusted.

[0065] Furthermore, with the front fork 1 configured in this way, the shape of the partition member 10 becomes a simple disc shape, thus reducing processing costs. Also, in the embodiments shown in Figures 2 to 4, the output shaft 10b was slidably inserted into the through hole 9b1 and its axial movement relative to the housing 9 was guided. However, as shown in Figure 5, when the partition member 10A consists only of the piston 10a, it is not necessary to slide the output shaft 10b against the through hole 9b1. Therefore, when the partition member 10A consists only of the piston 10a, as shown in Figure 5, the communication hole 9b2 provided in the bottom 9b of the housing 9 may be omitted, and the diameter of the through hole 9b1 may be made larger than the outer diameter of the pressing body 4 so that the gap G communicates with the annular groove 3b2 through the through hole 9b1. In this way, it is not necessary to process the bottom 9b to form the communication hole 9b2, thus simplifying the manufacturing of the housing 9. However, the pressing body 4 may be slidably inserted into the through hole 9b1 to guide the axial movement of the pressing body 4.

[0066] Furthermore, as shown in Figure 6, the front fork 1 has a partition member 10 that can move axially within the housing 9, and the actuator unit 8 may be provided with a stroke sensor 23 for detecting the stroke position of the partition member 10. Although not described in detail, the stroke sensor 23 comprises a cylindrical housing portion 23a connected to the bottom portion 9b of the housing 9, and a movable rod 23b that is inserted into the housing portion 23a so as to be movable axially, with its upper end protruding from the housing portion 23a connected to a piston 10a and moving axially together with the piston 10a. The stroke position of the partition member 10 can be detected by detecting the position of a detection element (not shown) provided on the movable rod 23b with a sensor (not shown) provided on the housing portion 23a.

[0067] Thus, by equipping the front fork 1 with a stroke sensor 23 capable of detecting the stroke position of the bulkhead member 10, the vehicle height can be adjusted while keeping track of the vehicle height of the front fork 1. The type of stroke sensor 23 is not particularly limited as long as it can detect the stroke position of the bulkhead member 10. For example, the stroke sensor 23 may consist of a sensor to be detected attached to the inner circumference of the bottom 9b of the housing 9 and a rod-shaped probe housed in a hole opening from the upper end of the bulkhead member 10 to detect the position of the sensor to be detected.

[0068] With the front fork 1 configured in this way, the stroke sensor 23 is provided on the actuator unit 8 side, which is detachable from the fork body 2, making it easy to install the stroke sensor 23. Also, in the event of a stroke sensor 23 failure, the actuator unit 8 can be detached, making it easy to replace or repair the stroke sensor 23.

[0069] Furthermore, the stroke sensor for determining the vehicle height of the front fork 1 may be provided on the fork body 2 side, and for example, the vehicle height of the front fork 1 may be determined by detecting the stroke position of the pressing body 4. In addition, if the pump 12 is a pump that comprises a cylinder and a piston inserted into the cylinder, and supplies and discharges liquid into the pressure chamber P by the movement of the piston relative to the cylinder, the stroke sensor may detect the position of the piston relative to the cylinder to detect the stroke position of the partition wall member 10.

[0070] Although preferred embodiments of the present invention have been described in detail above, modifications, alterations, and changes are permitted as long as they do not deviate from the scope of the claims. [Explanation of Symbols]

[0071] 1...Front fork, 2...Fork body, 3...Cap, 3a...Connecting part (mounting part), 3b...Intermediate part (insertion part), 4...Pressing body, 5...Suspension spring, 6...Spring receiver, 7...First seal, 8...Actuator unit, 9...Housing, 9a...Cylindrical part, 9b...Bottom part, 9b1...Through hole, 10...Partition member, 10a...Piston, 10b...Output shaft, 11...Second seal, 12...Pump, 23...Stroke sensor

Claims

1. A retractable fork body having a vehicle-side tube and a wheel-side tube, A cylindrical cap is attached to one end opening of the vehicle body side tube, A pressing body is inserted into the cap so as to be slidable in the axial direction, A spring support that moves axially together with the pressing body while supporting the cap-side end of the suspension spring housed within the fork body and biasing the fork body in the extension direction, A first seal that seals the space between the pressing body and the cap, The spring receiver is provided with an actuator unit that can drive the cap axially via the pressing body, The actuator unit is A housing that is detachably connected to the aforementioned cap and has a pressure chamber, A partition member, when inserted into the pressure chamber, that maintains liquid-tightness within the pressure chamber and transmits the pressure of the pressure chamber to the pressing body, The system includes a pump for supplying and discharging liquid to the pressure chamber. A front fork characterized by the following features.

2. The partition member has a second seal that seals the pressure chamber. The front fork according to feature 1.

3. The inner circumference of the cap is provided with a cylindrical insertion portion into which the cylindrical pressing body is inserted, and a cylindrical mounting portion which has a larger diameter than the insertion portion into which the housing is inserted. The housing has a cylindrical portion that is inserted into the mounting portion, and a bottom portion that closes the pressing body side end of the cylindrical portion and has a through hole facing the pressing body in the axial direction. The partition member has a disc-shaped piston that is movable in the axial direction while sliding against the inner circumference of the cylindrical portion, and an output shaft that protrudes from the bottom end of the piston and is inserted into the through hole while contacting the pressing body. The axial length of the output shaft is set to the length at which the end of the output shaft protrudes from the bottom when the piston is furthest from the bottom. The axial length of the pressing body is set to the length at which the end of the pressing body protrudes from the insertion portion toward the mounting portion when the spring receiver is at its highest position. The front fork according to feature 2.

4. The partition member is a disc-shaped piston that is movable in the axial direction while sliding against the inner circumference of the housing, The end of the pressing body abuts against the piston within the housing. The front fork according to feature 2.

5. The partition member is movable axially within the housing, The actuator unit is provided with a stroke sensor for detecting the stroke position of the partition wall member. A front fork according to any one of the features 1 to 4.

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