TWI813707B - front fork - Google Patents

Abstract

To provide a front fork that can freely set the compression side orifice and can generate stable damping force. It is equipped with: a piston part (20), which is an inner tube (2) installed on the vehicle body side, and divides an extension side chamber between the outer tube (1) on the wheel side and the pressure cylinder (3) installed inside it. (L1) and the lower chamber (O); and the cover (4), which is fixed on the upper end of the pressure cylinder (3) and separates the inner chamber (I) of the pressure cylinder that together with the lower chamber (O) forms the compression side chamber (L2) ) and the storage chamber (R); and the extension side orifice (3d), which provides resistance to the flow of liquid from the extension side chamber (L1) toward the compression side chamber (L2); and the compression side orifice (4f), which is Connecting the compression side chamber (L2) and the storage chamber (R); and the extension side check valve (7), which allows the flow of liquid from the storage chamber (R) to the compression side chamber (L2); and the compression side check valve (7) 6), which allows the flow of liquid from the storage chamber (R) or the compression side chamber (L2) to the extension side chamber (L1).

Description

front fork

The present invention relates to a front fork.

Conventionally, a front fork for a front wheel of a saddle type vehicle has an outer tube and an inner tube that can be slidably inserted into the outer tube. Telescopic type pipe members. Furthermore, among the front forks, for example, as disclosed in Japanese Patent JPH09-217780A, there is a so-called upright type front fork in which an outer tube is provided on the wheel side and an inner tube is provided on the vehicle body side (for example, Patent Document 1) .

Then, in such an upright front fork, a cylinder is installed inside the outer tube, and a liquid chamber is formed between the outer tube and the cylinder, and a cylinder is formed from the inside of the cylinder toward it. The reservoir chamber formed on the upper side is separated, and a piston portion provided at the lower end of the inner tube divides the liquid chamber into an expansion side chamber and a compression side chamber. Furthermore, the pressure cylinder is formed with an expansion side orifice that communicates with the expansion side chamber and the storage chamber, and a compression side chamber orifice that communicates with the compression side chamber with the storage chamber.

According to the above structure, when the front fork is extended, the liquid in the extension side chamber passes through the extension side hole and moves to the storage chamber, and a damping force on the extension side is generated due to the resistance given to the flow of the liquid. On the contrary, when the front fork contracts, the liquid in the compression side chamber will pass through the compression side hole and move to the storage chamber, and a damping force on the compression side caused by the resistance given to the flow of the liquid will be generated.

In conventional front forks, the damping force on the compression side was adjusted by changing the size of the compression-side hole formed in the pressure cylinder. Then, if you want to increase the damping force on the compression side, you only need to reduce the compression side orifice.

However, the compression side port formed in the pressure cylinder will also become a suction passage for supplying liquid from the storage chamber to the extension side of the compression side chamber during the extension stroke of the front fork. Therefore, when the compression side orifice is reduced, insufficient suction occurs in the compression side chamber during the extension stroke, and sometimes the compression side chamber becomes negative pressure. Then, when the compression side chamber becomes negative pressure during the extension stroke, the rise of the damping force on the compression side in the subsequent compression stroke will be slowed down, and the rider will have an uncomfortable feeling as if the damping force is lost.

In this way, in conventional front forks, it is sometimes impossible to generate a stable damping force in the compression side chamber by setting the compression side orifice, and the range in which the size of the compression side orifice can be changed is limited. Therefore, the present invention was developed to solve such problems, and its purpose is to provide a front fork that can freely set the compression side orifice and can generate a stable damping force.

A front fork that solves the above problem is equipped with: a piston part, which is an inner tube provided on the vehicle body side, and divides the outer tube on the wheel side and the pressure cylinder installed inside the piston part into an extension side chamber and a lower chamber; and a cover, which is fixed to the upper end of the pressure cylinder and separates the inner chamber of the pressure cylinder and the storage chamber that together form the compression side chamber with the lower chamber; The flow provides resistance; and the compression side orifice connects the compression side chamber and the storage chamber; and the extension side check valve (check valve) allows the flow of liquid from the storage chamber toward the compression side chamber; and the compression side check valve , which allows the flow of liquid from the storage chamber or the compression side chamber toward the extension side chamber.

The front fork according to the embodiment of the present invention will be described below with reference to the drawings. The same symbols attached to several drawings indicate the same parts or corresponding parts. In addition, unless otherwise specified, when the front fork is installed on the vehicle, it is referred to as "upper" or "lower" for short.

As shown in FIG. 1 , a front fork F according to one embodiment of the present invention refers to a suspension device that suspends the front wheel W in a saddle-type vehicle V. The so-called saddle-type vehicle refers to all vehicles in which one rides on the saddle as if riding on the saddle, and includes motorcycles, scooters, bicycles, etc. The front fork of the present invention can also be mounted on any saddle-type vehicle.

Next, the specific structure of the front fork F according to one embodiment of the present invention will be described. The front fork F is equipped with a telescopic tube member T composed of an outer tube 1 and an inner tube 2 . Furthermore, the front fork F is of an upright type, and the inner tube 2 can be slidably inserted from the upper side opening of the outer tube 1 .

Then, the outer tube 1 is integrally provided with a wheel-side bracket BW, and the outer tube 1 is connected to the axle of the front wheel W through the wheel-side bracket BW. On the other hand, the inner tube 2 is connected to the vehicle body B through the vehicle body side bracket BB connected to the upper end portion thereof.

In this way, the front fork F is arranged with the outer tube 1 facing the front wheel (wheel) W side, and the inner tube 2 facing the vehicle body B side, and is interposed between the vehicle body B and the axle of the front wheel W. Then, when the saddle-type vehicle V travels on a bumpy road surface and the front wheel W vibrates up and down, the inner tube 2 moves in and out of the outer tube 1 to expand and contract the front fork F.

Next, the upper end opening of the inner tube 2 is blocked by a cap (not shown). On the other hand, as shown in Fig. 2, the outer tube 1 has a bottomed cylindrical shape, and the lower opening of the outer tube 1 is blocked by the bottom 1a. Furthermore, the overlapping portion between the outer tube 1 and the inner tube 2 is blocked by an oil seal 10 and a dust seal 11 . In this way, the inside of the pipe member T is formed as a sealed space, and the liquid and gas are sealed in the pipe member T.

In addition, the pressure cylinder 3 is connected to the bottom 1a of the outer tube 1 with bolts 30. The pressure cylinder 3 includes a cylindrical portion 3a and an annular valve case portion 3b protruding radially outward from the front end of the cylindrical portion 3a. Then, the cylindrical portion 3a is erected at the center of the outer tube 1 along the axial direction, and the valve box portion 3b is inserted into the inner side of the inner tube 2 so as to be movable in the axial direction. Furthermore, a cover 4 for closing the upper end of the pressure cylinder 3 is stacked on the upper end of the valve box portion 3b.

Thereby, in the pipe member T, a storage chamber R is formed on the inner circumferential side of the inner pipe 2 and on the upper side of the valve box portion 3b and the cover 4, and a storage chamber R is formed on the inner circumferential side of the pressure cylinder 3 and on the lower side of the cover 4. The inner chamber 1 of the pressure cylinder has a cylindrical gap (not shown) formed between the pressure cylinder 3 and the outer tube 1. Then, the cylindrical gap and the cylinder inner chamber I are respectively filled with liquid such as hydraulic oil. On the other hand, in the storage chamber R, the same liquid as the above-mentioned liquid is stored, and a gas such as air is sealed above the liquid surface.

In addition, the cylindrical gap between the outer tube 1 and the pressure cylinder 3 is divided into an upper extension side chamber L1 and a lower lower chamber O by the piston portion 20 provided at the lower end of the inner tube 2 . The lower chamber O communicates with the cylinder inner chamber I through the communication hole 3c formed in the lower end of the pressure cylinder 3, and together with the cylinder inner chamber I, forms the compression side chamber L2. In other words, the lower chamber O and the inner chamber I of the pressure cylinder function as a series of chambers (compression side chamber L2), and the liquid can freely flow between the lower chamber O and the pressure cylinder through the communication hole 3c of the pressure cylinder 3. Between room I.

In addition, an extension-side hole 3d is formed on the upper part of the cylindrical portion 3a of the pressure cylinder 3, and the extension-side chamber L1 and the cylinder inner chamber I can be communicated through the extension-side hole 3d. Then, when the front fork F is extended, the liquid passes through the extension side hole 3d and flows from the extension chamber L1 to the cylinder inner chamber I, and resistance is given to the flow.

Next, as shown in FIG. 3 , an annular valve receiving gap 20 a is formed on the inner circumference of the piston portion 20 . In this valve accommodating gap 20a, an annular valve 5 that is in sliding contact with the outer periphery of the cylindrical portion 3a of the pressure cylinder 3 can be inserted so as to be movable in the axial direction. In addition, a portion of the piston portion 20 facing the lower end of the valve 5 becomes a seat surface 20b, and the valve 5 is separated from and seated on the seat surface 20b.

Then, when the front fork F contracts, the valve 5 is separated from the valve seat surface 20b, and the liquid is allowed to flow through the outer peripheral side of the valve 5 and from the lower chamber O toward the extension side chamber L1. On the contrary, when the front fork F is extended, the valve 5 will be seated on the valve seat surface 20b and the liquid will not be able to pass through the outer peripheral side of the valve 5. Instead, it will pass through the sliding gap between the valve 5 and the pressure cylinder 3 and exit from the extension side chamber L1. Move towards the lower room O. Since the sliding gap is a very narrow gap, resistance is given to the flow of liquid from the extension side chamber L1 toward the lower chamber O.

As mentioned above, the lower chamber O and the inner chamber I of the pressure cylinder are connected, and these become part of the compression side chamber L2. In other words, the expansion side port 3d and the valve 5 simultaneously function as an expansion side damping element that provides resistance to the flow of liquid from the expansion side chamber L1 toward the compression side chamber L2 when the front fork F is extended. Furthermore, the valve 5 also has a function as a compression side check valve that opens when the front fork F contracts to allow the flow of liquid from the compression side chamber L2 to the expansion side chamber L1.

Furthermore, an extension spring 21 is laminated on the upper side of the piston portion 20 . Then, the tension spring 21 is compressed between the piston part 20 and the valve box part 3b when the front fork F is extended the most, thereby alleviating the impact when the front fork F is extended the most. Furthermore, although the tension spring 21 shown in FIG. 2 is a coil spring, it may be a spring other than a coil spring. In addition, instead of the tension spring 21, cushion rubber or the like may be provided, and the cushion rubber may be used to cushion the impact when the front fork F is extended the longest.

Next, an annular valve receiving groove 3e is formed on the outer periphery of the valve box portion 3b formed at the upper end of the pressure cylinder 3. Then, inside the valve accommodating groove 3e, an annular compression-side check valve 6 that is in sliding contact with the inner periphery of the inner pipe 2 is inserted so as to be movable in the axial direction. In addition, the portion of the wall surface of the valve receiving groove 3e that faces the upper end of the compression-side check valve 6 becomes the valve seat surface 3f, and the compression-side check valve 6 is separated from and seated on the valve seat surface 3f.

Then, when the front fork F contracts, the compression side check valve 6 is separated from the valve seat surface 3f and allows liquid to pass through the inner circumferential side of the compression side check valve 6 and flow from the storage chamber R toward the extension side chamber L1. On the contrary, when the front fork F is extended, the compression side check valve 6 will be seated on the valve seat surface 3f, and the communication between the storage chamber R and the extension side chamber L1 will be cut off.

Furthermore, as shown in Figures 3 and 4, the cover 4 laminated on the upper side of the valve box portion 3b includes an annular valve seat portion 4a; and an annular leg portion 4b, which is formed from the valve seat portion 4a. The lower end outer peripheral portion protrudes toward the lower side; and an annular boss portion 4c protrudes upward from the upper end inner peripheral portion of the valve seat portion 4a; and a plurality of branch portions 4d, which protrude from the valve seat portion 4a. 4 a protrudes upward and extends radially from the boss portion 4 c toward the outer peripheral side of the cover 4 . Figure 3 is a cross-section along line X-X in Figure 4 showing the cover 4.

In this way, the suspension spring S composed of a coil spring is fitted on the outer periphery of the plurality of branch portions 4d extending radially. Then, the cover 4 is pressed against the valve box part 3b by the suspension spring S, and the front end of the leg part 4b is fixed so that it does not leave the valve box part 3b.

Therefore, the lower end of the suspension spring S can ensure that the intermediary cover 4 is always supported by the pressure cylinder 3 . On the other hand, the upper end of the suspension spring S is supported by a cap (not shown) that blocks the upper end of the inner tube 2 . In other words, the suspension spring S of this embodiment can be said to be installed intermediately between the pressure cylinder 3 and the inner tube 2 .

Then, when the inner tube 2 invades the outer tube 1 and the front fork F contracts, the amount of compression of the suspension spring S becomes larger, and the elastic force of the suspension spring S that resists the compression becomes larger. In this way, the suspension spring S exerts an elastic force commensurate with the amount of compression, and urges the front fork F in the extension direction to elastically support the vehicle body B.

Furthermore, a port 4e is formed on the cover 4, and an extension side check valve 7 is laminated to open and close the port 4e that is disengaged and seated on the lower side of the valve seat 4a. They are respectively opened between the adjacent branch portions 4d, 4d and the leg portion 4b on the outer peripheral side of the boss portion 4c, and communicate with the storage chamber R and the inner chamber I of the pressure cylinder.

Then, when the front fork F is extended, the extension-side check valve 7 separates from the valve seat 4a to open the port 4e, and allows liquid to pass through the port 4e and flow from the storage chamber R toward the cylinder inner chamber I. On the contrary, when the front fork F contracts, the extension side check valve 7 is seated on the valve seat portion 4a and maintains the closed state of the port 4e.

Furthermore, the leg portion 4b of the cover 4 is formed with one or more holes penetrating the leg portion 4b in the radial direction, and the compression side opening 4f is formed by the holes. Moreover, the outer diameter of the cover 4 is smaller than the inner diameter of the inner tube 2, and an annular gap is formed between the cover 4 and the inner tube 2.

Therefore, if the opening of the compression side port 4f is blocked by the inner tube 2, the storage chamber R and the pressure cylinder inner chamber I can be connected through the compression side port 4f. Then, when the front fork F contracts, the liquid passes through the compression side hole 4f and flows from the cylinder inner chamber I toward the storage chamber R, and resistance is given to the flow.

Next, the operation of the front fork F according to one embodiment of the present invention will be described.

When the front fork F with the inner tube 2 withdrawing from the outer tube 1 is extended, the inner tube 2 withdraws from the cylindrical gap between the outer tube 1 and the pressure cylinder 3, and the piston part 20 moves upward into the gap to shrink. The side chamber L1 is extended, and the lower chamber O is enlarged.

Then, when the front fork F is extended, the liquid in the reduced extension side chamber L1 passes through the extension side hole 3d and moves toward the cylinder inner chamber I, and passes through the sliding gap between the valve 5 and the pressure cylinder 3 to expand. The lower chamber O moves. At this time, in the lower chamber O, the liquid flows into the cylinder inner chamber I through the communication hole 3c, and the extension side check valve 7 opens and the liquid is supplied from the storage chamber R to the cylinder inner chamber I.

During the extension stroke of the front fork F, the extension side port 3d and the valve 5 provide resistance to the flow of liquid from the extension chamber L1 toward the cylinder inner chamber I and the lower chamber O (compression side chamber L2). . Therefore, when the front fork F is extended, the pressure in the extension-side chamber L1 increases, and a damping force on the extension side that hinders the extension operation of the front fork F is generated.

On the contrary, when the front fork F with the inner tube 2 penetrating into the outer tube 1 contracts, the inner tube 2 will intrude into the cylindrical gap between the outer tube 1 and the pressure cylinder 3, and the piston part 20 will move downward to this position. The lower chamber O is narrowed in the gap, and the elongated side chamber L1 is enlarged.

Then, when the front fork F contracts, the valve 5 and the compression side check valve 6 open, and the liquid in the contracted lower chamber O and the liquid in the storage chamber R move toward the enlarged expansion side chamber L1. Furthermore, when the front fork F contracts, the liquid equivalent to at least the volume of the inner tube 2 that has invaded the cylindrical gap between the outer tube 1 and the pressure cylinder 3 will become redundant, and the excess liquid will pass through the communication hole. 3c and moves from the lower chamber O toward the pressure cylinder inner chamber I, and is discharged from the pressure cylinder inner chamber I toward the storage chamber R through the compression side port 4f.

During the contraction stroke of the front fork F, resistance is provided to the flow of liquid from the cylinder inner chamber I (compression side chamber L2) toward the storage chamber R by the compression side orifice 4f. Therefore, when the front fork F contracts, the pressure in the compression side chamber L2 increases, and a compression-side damping force that hinders the contraction operation of the front fork F is generated.

Furthermore, in this embodiment, the cylinder inner chamber I inside the cylinder 3 becomes a part of the compression side chamber L2, and the pressure in the cylinder inner chamber I rises during the contraction stroke of the front fork F. Therefore, the expansion side chamber L1 that expands during the contraction stroke is also supplied with liquid from the cylinder inner chamber I through the expansion side hole 3d. Therefore, the pressure of the expansion-side chamber L1 tends to become higher in the subsequent expansion stroke, and the reactivity of the expansion-side damping force generation is improved.

Furthermore, in this embodiment, the compression side port 4f is formed in the horizontal direction along the radial direction of the cover 4, and the opening of the compression side port 4f faces the inner peripheral surface of the inner tube 2. Therefore, the liquid flowing from the inner chamber I of the pressure cylinder toward the storage chamber R will not be ejected toward the liquid surface of the storage chamber R. Therefore, the liquid in the storage chamber R is less likely to bubble.

When the liquid in the storage chamber R bubbles, the liquid will be sucked in from the storage chamber R toward the extension side chamber L1 or the compression side chamber L2 during the expansion and contraction stroke of the front fork F. The bubbles and liquid in the storage chamber R will be sucked together, causing attenuation. The reason for the decrease in force production reactivity. However, as mentioned above, as long as the bubbling of the liquid in the storage chamber R is suppressed, the decrease in the damping force generation reactivity caused by the mixing of bubbles can be suppressed.

Hereinafter, the function and effect of the front fork F according to one embodiment of the present invention will be described.

The front fork F of this embodiment is equipped with: an outer tube 1 on the W side of the front wheel (wheel); an inner tube 2 on the B side of the vehicle body, which is slidably inserted into the outer tube 1; and a pressure cylinder 3. It is arranged in the outer tube 1, and the upper end is movably inserted into the inner tube 2; and the piston part 20 is arranged in the inner tube 2, and divides the space between the outer tube 1 and the pressure cylinder 3 into an elongation side chamber L1 with lower chamber O.

In addition, the front fork F of this embodiment is equipped with a cover 4 fixed to the upper end of the pressure cylinder 3. This cover 4 separates the storage chamber R on the upper side of the pressure cylinder 3 and the cylinder inner chamber inside the pressure cylinder 3. I. This cylinder inner chamber I forms a compression side chamber L2 together with the lower chamber O on the outer peripheral side of the cylinder 3 .

Furthermore, the front fork F of this embodiment is equipped with an extension-side orifice (extension-side damping element) 3d and a valve (extension-side damping element) 5 that controls the flow of liquid from the extension-side chamber L1 to the compression-side chamber L2. and the compression side orifice 4f, which provides resistance to the flow of liquid from the compression side chamber L2 toward the storage chamber R; and the extension side check valve 7, which allows the flow of liquid from the storage chamber R toward the compression side chamber L2. flow; and the valve (compression side check valve) 5 and compression side check valve 6, which allow the flow of liquid from the storage chamber R or the compression side chamber L2 to the extension side chamber L1.

According to the above structure, even if the compression side orifice 4f is narrowed in order to adjust the damping force on the compression side, liquid will still be supplied from the storage chamber R to the compression side chamber L2 through the extension side check valve 7 during the extension stroke of the front fork F. . Therefore, even if the compression side orifice 4f is reduced, the compression side L2 will not become a negative pressure during the extension stroke, and the damping force on the compression side can be rapidly increased during the subsequent compression stroke.

In other words, according to the above structure, a stable damping force can be generated even immediately after switching from the expansion stroke to the compression stroke without setting the compression side orifice 4f. Therefore, in the front fork F of this embodiment, the compression side orifice 4f can be freely set, and a stable damping force can be generated.

Also, for example, when an on-off type valve is used to generate the damping force on the compression side, and when the valve is urged in the closing direction by a suspension spring, the force generated depends on the stroke position of the front fork (the position of the piston part). The damping force on the compression side will change. Moreover, the damping force characteristics of the compression side will also change depending on the specifications of the suspension spring. In addition, when the valve seat surface is large, there is a risk that the pressure in the pressure side chamber will drop sharply and the damping force will suddenly change due to the opening of the valve.

On the other hand, according to the above-mentioned structure, since the compression side hole 4f can be used to generate the damping force on the compression side, a stable damping force can be generated in the entire stroke range of the front fork F. Furthermore, in order to adjust the damping force on the compression side, it is only necessary to change the flow path area of the compression side orifice 4f. Since this change can be easily performed, the damping force on the compression side can also be easily adjusted according to the above configuration.

Furthermore, the front fork F of this embodiment is provided with the extension side hole 3d formed in the pressure cylinder 3 and the valve 5 mounted on the piston part 20 as a means of controlling the liquid flowing from the extension side chamber L1 to the outside. The elongated side attenuation elements provide resistance to flow. However, one of the extension-side orifice 3d and the valve 5 may be omitted, and the structure of the extension-side damping element may be appropriately changed.

Furthermore, in this embodiment, the compression side check valve 6 installed on the valve box part 3b of the pressure cylinder 3 and the valve 5 installed on the piston part 20 are provided as suction valves toward the expansion side chamber L1. Compression side check valve for liquids. However, one of the compression side check valve 6 and the valve 5 may be omitted, and the structure of the compression side check valve may be appropriately changed.

Furthermore, in this embodiment, the compression side port 4f opens toward the inner peripheral surface of the inner tube 2 . Therefore, during the contraction stroke of the front fork F, the liquid from the cylinder inner chamber I toward the storage chamber R will not be ejected toward the liquid surface of the storage chamber R, and bubbling of the liquid in the storage chamber R can be suppressed. Therefore, it is possible to suppress the mixing of bubbles into the expansion side chamber L1 and the compression side chamber L2, and to suppress the decrease in damping force generation reactivity caused by the mixing of bubbles.

However, the opening direction of the compression side port 4f is not limited to the above, and can be appropriately changed. Moreover, in this embodiment, although the compression side port 4f is formed by the hole already formed in the cover 4, the structure and arrangement of this compression side port 4f may be changed suitably. For example, a notch along the radial direction may be formed at the lower end of the leg portion 4b that serves as the opposing portion between the cover 4 and the pressure cylinder 4, or at the upper end of the valve box portion 3b, and the compression side port may be formed by the notch. .

Then, such a change can be performed without using the expansion-side damping element and the compression-side check valve.

Moreover, in this embodiment, the cover 4 is laminated on the upper end of the pressure cylinder 3, and is pressed and fixed to the pressure cylinder 3 by the suspension spring (coil spring) S which elastically supports the vehicle body B. In this way, in this embodiment, the cover 4 and the pressure cylinder 3 are formed separately, and the cover 4 can be fixed to the pressure cylinder 3 by the elastic force of the suspension spring S.

According to the above structure, the cover 4 can be fixed to the pressure cylinder 3 by using the suspension spring S after the pressure cylinder 3 is fixed to the inside of the outer tube 1 with the bolts 30 and liquid is injected into the pressure cylinder 3 . Therefore, during the assembly process of the front fork F, the liquid can be filled without blocking the pressure cylinder 3 with the cover 4, so the liquid filling operation can be performed quickly.

Furthermore, in this embodiment, the suspension spring (coil spring) S is fitted to the cover 4 . According to this configuration, as described above, when the cover 4 is fixed to the pressure cylinder 3 with the suspension spring S after the liquid is injected into the pressure cylinder 3 , the cover 4 can be prevented from being displaced from the pressure cylinder 3 . Therefore, according to the above structure, the assembly work of the front fork F can be easily performed.

Furthermore, in this embodiment, the cap 4 includes an annular valve seat portion 4a; an annular leg portion 4b protruding downward from the lower end outer peripheral portion of the valve seat portion 4a; and an annular leg portion 4b. The boss portion 4c protrudes upward from the inner peripheral portion of the upper end of the valve seat portion 4a; and a plurality of branch portions 4d protrudes upward from the valve seat portion 4a and projects toward the outer peripheral side of the cover 4 from the boss portion 4c. Extend radially.

Moreover, the cover 4 is formed with a port 4e, which is opened between the adjacent branch portions 4d and 4d on the outer peripheral side of the boss portion 4c and the inside of the leg portion 4b, and communicates with the storage chamber. R and the inner chamber I of the pressure cylinder. Then, the extension side check valve 7 is separated from its seat and seated on the lower side of the valve seat portion 4a to open and close the port 4e, and the suspension spring (coil spring) S is integrally surrounded by the outer periphery of the plurality of branch portions 4d. Come chimera.

According to the above structure, since the port 4e is opened on the inner peripheral side of the suspension spring (coil spring) S, even if the suspension spring (coil spring) S is fitted into the cover 4, the port 4e can be prevented from being blocked by the suspension spring S. clogged. Furthermore, since the port 4e can be arranged on the outer peripheral side of the cover 4, the flow path area of the port 4e can be easily increased, and insufficient suction of the compression side chamber L2 during the extension stroke of the front fork F can be reliably prevented.

However, the structure of the cover 4 is not limited to the above, and can be appropriately changed. For example, in this embodiment, four branch portions 4d and four ports 4e are respectively formed, but the numbers of the branch portions 4d and the ports 4e can be freely changed. Moreover, the state in which the cover 4 fixes the pressure cylinder 3 means that the cover 4 does not separate from the pressure cylinder 3 when the front fork F is telescopically operated, and the structure for achieving such a state may be appropriately changed.

Specifically, as shown in FIG. 5 , the cover 4 may be screwed and fixed to the pressure cylinder 3 . Then, in the case where the cover 4 is fixed to the pressure cylinder 3 without utilizing the biasing force of the suspension spring S, the structure and arrangement of the suspension spring S can be changed. For example, the suspension spring S may be a spring other than a coil spring such as an air spring. Alternatively, the suspension spring S may be installed intermediary between the lower end of the inner tube 2 and the bottom 1 a of the outer tube 1 .

Then, these changes can be carried out without using the structure of the telescopic side damping element, the compression side check valve, and the compression side orifice.

Although the preferred embodiments of the present invention have been described in detail above, modifications, changes, and changes can still be made without departing from the scope of the patent application.

This application claims priority based on Japanese Patent Application No. 2018-123915, which was filed with the Japan Patent Office on June 29, 2018. The entire contents of this application are incorporated into this specification by reference.

1:Outer tube 1a: Bottom 2:Inner tube 3: Pressure cylinder 3a: Cylindrical part 3b: Valve box department 3c: Connecting hole 3d: Extended side opening 3e: Valve storage tank 3f: Valve seat surface 4: cover 4a: Valve seat part 4b: Feet 4c: Boss part 4d: Branch department 4e:Port 4f: Compression side orifice 5: valve 6: Compression side check valve 7:Extension side check valve 10:Oil seal 11: Dustproof seal 20:Piston part 20a: Valve receiving clearance 20b: Valve seat surface 21: Tension spring 30:bolt B:Car body BB: body side bracket BW: wheel side bracket F: Front fork I: Inner chamber of pressure cylinder L1: Extended side chamber L2: Compression side chamber O:Lower room R: storage room S: suspension spring T: pipe member V: Saddle vehicle W: Front wheel (wheel)

FIG. 1 is a simplified side view showing an installed state of a front fork according to an embodiment of the present invention. Fig. 2 is a longitudinal sectional view of the front fork according to one embodiment of the present invention. FIG. 3 is an enlarged longitudinal cross-sectional view showing a part of FIG. 2 . FIG. 4 is an enlarged plan view showing the cover of the front fork according to one embodiment of the present invention. FIG. 5 is an enlarged vertical cross-sectional view showing a modified example of the front fork according to one embodiment of the present invention, and showing the modified part in an enlarged manner.

1:Outer tube

1a: Bottom

2:Inner tube

3: Pressure cylinder

3a: Cylindrical part

3b: Valve box department

3c: Connecting hole

3d: Extended side opening

4: cover

4e:Port

4f: Compression side orifice

5: valve

6:Compression side check valve

7:Extension side check valve

10:Oil seal

11: Dustproof seal

20:Piston part

21: Tension spring

30:bolt

F: Front fork

I: Inner chamber of pressure cylinder

L1: Extended side chamber

L2: Compression side chamber

O:Lower room

R: storage room

S: suspension spring

T: pipe member

Claims (4)

A front fork, characterized by: having: an outer tube on the wheel side; an inner tube on the vehicle body side, which is slidably inserted into the outer tube; and a pressure cylinder, which is installed inside the outer tube, and The upper end is movably inserted into the aforementioned inner tube; and a piston portion is provided in the aforementioned inner tube and divides the space between the aforementioned outer tube and the aforementioned pressure cylinder into an elongated side chamber and a lower chamber; and a cover, which is fixed to the aforementioned inner tube. The upper end of the pressure cylinder separates the storage chamber formed on the upper side of the aforementioned pressure cylinder and the inner chamber of the pressure cylinder formed on the inside of the aforementioned pressure cylinder and constitutes the compression side chamber together with the aforementioned lower chamber; and an extension side attenuation element, which is Providing resistance to the flow of liquid from the aforementioned extension side chamber toward the aforementioned compression side chamber; and a compression side orifice formed in the aforementioned cover and connecting the aforementioned compression side chamber and the aforementioned storage chamber; and an extension side check valve that allows the flow from the aforementioned expansion side chamber to the aforementioned compression side chamber. a flow of liquid from the storage chamber toward the compression side chamber; and a compression side check valve that allows the flow of liquid from the storage chamber or the compression side chamber toward the expansion side chamber. A front fork characterized by: having: an outer tube on the wheel side; and an inner tube on the vehicle body side, which is slidably inserted into the aforementioned outer tube; and a pressure cylinder, which is provided inside the aforementioned outer tube and whose upper end is movably inserted into the aforementioned inner tube; and a piston portion, which is It is provided on the aforementioned inner tube and divides the space between the aforementioned outer tube and the aforementioned pressure cylinder into an elongated side chamber and a lower chamber; and a cover, which is fixed on the upper end of the aforementioned pressure cylinder and separates the storage formed on the upper side of the aforementioned pressure cylinder. chamber, and an inner chamber of the pressure cylinder formed inside the aforementioned pressure cylinder and forming a compression side chamber together with the aforementioned lower chamber; and an extension side attenuation element that provides resistance to the flow of liquid from the aforementioned extension side chamber toward the aforementioned compression side chamber; and a compression side orifice that connects the compression side chamber and the storage chamber; an extension side check valve that allows the flow of liquid from the storage chamber toward the compression side chamber; and a compression side check valve that allows the flow from the storage chamber to the compression side chamber. The storage chamber or the compression side chamber flows toward the expansion side chamber, and the lid is stacked on the upper end of the pressure cylinder, and is pressed and fixed to the pressure cylinder by a coil spring that elastically supports the vehicle body. For example, in the front fork of claim 1 or 2, the compression side opening opens toward the inner circumferential surface of the inner tube. For example, in the second item of the patent application, the aforementioned spiral bullet The spring is fitted to the aforementioned cover.