JPS61200077A - Sinking preventive device for front fork - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an improvement in a device for preventing a front fork from sinking during braking in a motorcycle or the like.

(Prior Art) In a motorcycle, when braking, the center of gravity shifts due to inertia, and the load sharing ratio applied to the front fork becomes large (this causes the front 7-o's to sink).

Therefore, various devices (anti-nose buib devices) have been proposed that detect the braking action and increase the compression-side damping force of the front fork to prevent the vehicle from sinking.

Among these, the one disclosed in Japanese Patent Publication No. 51-47945 is that the brake caliper of a disc brake is mounted via a link lever etc. so that the brake caliper moves during braking, and the movement of the brake caliper is controlled by the link lever etc. The signal is mechanically transmitted to the anti/-sub-build valve to close it.

Since this directly senses the braking action of the brake caliper, it is possible to accurately adjust the damping force on the compression side of the front seven orifices, and prevent the front seven orifices from sinking to the compression side.

(Problem to be solved by the invention) However, since the anti-nose dive valve is connected to the brake caliper via a link lever etc.
Not only does the anti-nose dive valve itself require structural strength to support the brake caliper against the front seven-way body, but when the wheel is pushed up due to uneven road surfaces during braking, the anti-nose dive valve relieves the pressure side flow. However, since the brake caliper also moves in conjunction with the opening of the anti-nose dive valve, there is a delay in opening the anti-nose dive valve.

The present invention aims to solve the above problem α.

(Means for Solving the Problems) According to the present invention, an anti-nose dive valve is interposed in the passage of hydraulic oil flowing from the oil chamber to the oil reservoir chamber in the pressure side stroke.

The valve seat on which the anti-nose dive valve is seated is movably provided via a relief spring.

One end of the link lever to which the brake caliper is attached is rotatably supported on the front fork body side, and the other end of the link lever is pivotally supported in a long hole formed on the front fork body side via an elastic body. The swinging end of the link lever is connected so that the anti-nose dive valve closes during braking, and the reaction force of the braking torque of the brake caliper is transmitted to the anti-nose dive valve via this link lever.

With this structure, the link lever that supports the brake caliper moves while compressing the elastic body due to the reaction force of the braking torque, but the reaction force of the braking torque applied to the brake caliper is fitted into the long hole on the front fork body side. Since the anti-nose dive valve is supported by an elastic body, the reaction force of braking torque is not directly applied to the anti-nose dive valve. The anti-nose dive valve only transmits the movement of the brake caliper as a signal, and the required strength of the anti-nose dive valve can be reduced. In addition, the anti-nose dive valve opens when the valve seat senses the internal pressure when it is pushed up from the road surface during braking, so it can absorb and alleviate such shocks and stabilize the operation of the disc brake. is measured.

(*Example) Embodiments of the present invention will be described below with reference to the accompanying drawings.

An inner tube 3 connected to the vehicle body side is slidably housed in an outer tube 2 supporting an axle, and a seat pipe 4 is positioned inside the inner tube 3 and erected on the outer tube 2.

An upper oil chamber A that expands during the compression stroke is defined between the inner tube 3 and the seat pipe 4, and a lower oil chamber B that also contracts during the compression stroke is defined between the outer tube 2 and the seat pipe 4. is defined at the tip of the inner tube 3, which applies resistance to the hydraulic oil flowing from oil chamber A to oil chamber B during the rebound stroke and generates a damping force on the rebound side, and conversely, during the compression stroke. A damping valve 5 is provided to allow hydraulic oil to flow smoothly from B to A.

A piston part 6 inscribed in the inner tube 3 is integrally provided at the upper end of the seat pipe 4, and the piston part 6 communicates with each other from the inside of the seat pipe 4 to the upper inside of the inner tube 3, and a part of the piston part 6 is filled with a gas. An oil reservoir chamber C is formed.

Note that a tapered cylindrical oil hole rod 5 is provided at the base of the seat pipe 4.
0 is fitted, and an oil lock is performed at the most advanced position of the inner tube 3. The oil hole rod 50 opens during the extension stroke and guides the hydraulic oil in the oil reservoir chamber C to the lower oil chamber B (.

7 At the bottom of the outer tube 2, there are a lower oil chamber B and an oil reservoir chamber C.
A passage 7 at 7 b is formed to communicate with the passages 7 a and 7 b, and an anti-nose dive valve 8 is interposed between the passages 7 a and 7 b.

The anti-nose dive valve 8 is slidably housed in a valve housing 10 attached to the lower side of the outer tube 2 via an end plate 11, and a valve body portion 12 that protrudes annularly is formed at the tip thereof. A return spring 17 is seated inside the valve body portion 12 to bias it in the opening direction.

An annular valve seat 15 on which the valve body portion 12 is seated is slidably housed in the valve hashing 10, and a ring 20 for positioning the valve seat 15 is attached to the pulp housing 10. A relief spring 18 that constantly biases the spring 15 is interposed.

Anti-nose dive valve 8 has return spring 17
When pushed in against the pressure, the flow of hydraulic oil from the passage 7a to the passage 7b is throttled between the valve body portion 12 and the valve seat 15, thereby increasing the damping force.

Next, a bracket 26 is attached to the lower part of the outer tube 2.
The lower end of the link lever 30 is rotatably supported by the bracket 26 via a pin 31.

A brake caliper 32 is attached to this link lever 30.

A bracket 27 is integrally protruded from the side of the outer tube 2, and a long hole 28 is formed in this bracket 27. Two elastic bodies made of, for example, a rubber material are inserted into the long hole 28. Fitted in.

A pin 33 is fixed to the upper end of the link lever 30, and this pin 33 is pivotally supported in the elongated hole 28 via an elastic body 29.

As a result, the upper end of the link lever 30 can move a short distance within the elongated hole 28 without compressing the elastic body 29 via the pin 33, and the brake caliper 32 can swing on the outer tube 2 with the pin 31 as a fulcrum. Installed.

An arm portion 35 is integrally formed on the link lever 30, and a bushing rod 36 is screwed onto the tip of the arm portion 35. The bushing rod 36 comes into contact with the base end of the anti-nose dive valve 8 to close the link. As the lever 30 swings, the anti-nose dive valve 8 is pushed in to close the valve.

Note that a lock nut 40 is attached to the upper end of the bushing rod 36.
are screwed together, and a rubber boot 41° is attached to the upper end of the valve housing 10 so as to cover the bushing rod 36.

The brake disc 37 rotates integrally with a wheel (not shown), and rotates clockwise as shown by an arrow in the figure.

During braking, the brake caliper 32 clamps the brake disc 37 with pads (not shown) to restrain rotation and apply braking torque.

Therefore, during braking, a reaction force of braking torque in the rotational direction of the brake disc 37 is applied to the brake caliper 32, and the link lever 30 is rotated clockwise in the figure. the anti-nose dive valve 8 is pushed in.

It is constructed as described above, and its operation will be explained next.

During normal driving, the anti-nose dive valve 8 is fully opened due to the biasing force of the return spring 17, as shown in the figure.

Therefore, in the pressure stroke, the hydraulic oil corresponding to the volume of entry of the inner tube 3 is transferred from the lower oil chamber B to the passage 7a.
The oil flows into the oil sump chamber C through the pulp housing 10 and the passage 7b. In this process, the anti-nose dive valve 8
Since it is fully open, there is almost no resistance to the flow of hydraulic oil, and the front fork absorbs compression side vibrations to maintain a soft ride.

In addition, in the extension stroke, resistance is applied to the hydraulic oil flowing from the upper oil chamber A to the lower oil chamber B via the damping valve 5, and a predetermined damping force is generated.

At this time, the oil hole rod 50 opens and hydraulic oil is directly sucked from the oil reservoir chamber C into the oil chamber B without passing through the 7-inch/- three-inch valve 8.

On the other hand, during deceleration braking, the brake caliper 32 restrains the rotation of the brake disc 37, and due to the reaction force of this braking torque, the brake caliper 32 attempts to rotate clockwise in the figure together with the link lever 30.

As a result, the link lever 30 rotates while compressing the elastic body 29, pushes the anti-nose dive valve 8 through the arm portion 35 and the bushing rod 36, and pushes the anti-nose dive valve 8 through the arm portion 35 and the bushing rod 36.
2 is seated on the valve seat 15.

As a result, with deceleration braking, the 70 ton sinks and the hydraulic oil in oil chamber B tries to flow into oil reservoir chamber C, but because the anti-nose dive valve 8 closes. Then, the flow of hydraulic oil from the passage 7a to the passage 7b is blocked, and the entry of the inner tube 3 is restricted.
In other words, the sinking of the front fork is suppressed.

At this time, the link lever 30 rotates while compressing the elastic body 29 due to the reaction force of the braking torque of the brake caliper 32, and the circular arc movement of the arm portion 35 is transferred to the bushing rod 3.
6 into a linear motion of the anti-nose dive valve 8.

That is, whereas in the past, the movement of the puke rake caliper was regulated by the completion of the closing operation of the anti-nose dive valve, in the present invention, the movement of the puke rake caliper was regulated by the completion of the closing operation of the anti-nose dive valve, whereas the present invention controls the movement of the puke rake caliper by the completion of the closing operation of the anti-nose dive valve. Fitted long hole 2
It is regulated by 9.

Therefore, although the anti-nose dive valve 8 is directly driven by the reaction force of the braking torque of the brake caliper 32 via the link lever 30, the anti-nose dive valve 8 is driven by the reaction force of the braking torque of the brake caliper 32. Only a part of the brake caliper is transmitted as a signal, and structural strength to support the brake caliper 32 against the front body side (outer tube 2) is not required as in the conventional case.

When the anti-nose dive valve 8 is blocking the flow of hydraulic oil on the pressure side during the above-mentioned braking, if the wheel pushes up due to unevenness from the road surface, the pressure in the oil chamber B applied to the valve seat 15 increases. , valve seat 1
5 is the valve body portion 12 while compressing the relief spring 18.
Relieve the pressure side hydraulic oil away from the By appropriately setting the valve opening pressure of the valve seat 15, it is possible to absorb the shock caused by thrusting up, which is larger than the depression caused by braking, and it is possible to prevent discomfort from being caused to the driver.

In this way, when relieving pressure hydraulic oil during braking, the anti-nose dive valve 8 is connected to the brake caliper 32.
Stable brake operation can be ensured without moving the brake.

The compression side damping force applied by the anti-nose dive valve 8 during braking can be easily adjusted by adjusting the screwing position of the bushing rod 36.

(Effects of the Invention) As described above, the present invention provides an anti-sinking device that drives an anti-nose dive valve by the reaction force of the braking torque of a brake caliper. Since the anti-nose dive valve is pivoted via an elastic body to a long hole formed in the front 7-hole, the anti-nose dive valve inputs a part of the reaction force of the braking torque as a signal, increasing the structural strength to support the brake caliper. Even if this is not required, stable brake operation is ensured even when the pressure side hydraulic oil is relieved by pushing up the wheel during braking.

[Brief explanation of drawings]

The drawing is a side sectional view showing one embodiment of the present invention. 2... Outer tube, 8... Anti-nose dive valve, 15... Valve seat, 18... Relief spring, 28... Long hole, 29... Elastic body, 3
0-0° link lever, 32...brake caliper,
33.. Bottle, 35...71 part, 36...Butschrod patent applicant Kayaba Kogyo Co., Ltd. Procedural amendment 1. Display of $ 1985 Patent Application No. 40791 2, Name of invention: Front fork sinking prevention device 3, Relationship with the person making the amendment case Patent applicant address: 2-4-1 Hamamatsucho, Minato-ku, Tokyo World Trade Center Building Name (092) Kayaba Kogyo Co., Ltd. 4, Agent 5, Date of Amendment Order Sponsored Planning A' Original Specification Name of Invention Front 7 O-Sinking Preventing Device Patent Claims Oil Room in Pressure Side Stroke One end of the brake caliper is rotatably supported on the side of the 70-ton hook main body, and the link lever A sinking prevention device for a front fork, characterized in that the other end of the link lever is pivotally supported on the side of the front fork body through an elastic body, and the swinging end of the link lever is controlled. DETAILED DESCRIPTION OF THE INVENTION (Field of application on M beams) The present invention relates to an improvement in a device for preventing the front seven oaks from sinking during braking in a motorcycle or the like. (Prior Art) In a motorcycle, when braking, the center of gravity shifts due to inertia, which increases the load sharing ratio applied to the front fork, causing the front fork to sink. Therefore, various devices (anti-nose dive devices) have been proposed that prevent sinking by sensing the braking action and increasing the compression side braking force of the front 7-wheel. Among these, the one disclosed in Japanese Patent Publication No. 51-47945 is that the brake caliper of a disc brake is mounted via a link lever etc. so that the brake caliper moves during braking, and the movement of the brake caliper is controlled by the link lever etc. The signal is mechanically transmitted to the anti-nose dive valve to close it. Since this system directly senses the braking torque reaction force as the movement of the brake caliper, it accurately blocks the pressure side passage of the front 7-o's depending on the braking effect, that is, the effectiveness of the brake, and causes the front 7-o's to sink to the pressure side. can be prevented from entering. (Problem to be solved by the invention) However, since the anti-nose dive valve is connected to the brake caliper via a link lever etc.
Not only does the anti-nose dive valve itself require structural strength to support the braking torque reaction force transmitted as the movement of the brake caliper, but when the wheel is pushed up due to uneven road surfaces during braking, the anti-nose dive valve I7-7 tries to absorb the shock by applying abnormal pressure, but when the anti-nose dive valve is pushed back in the opening direction, the brake caliper also moves in the opposite direction to the brake disc, causing the movable mass to move. is large, and anti/-:X dive pulp has poor responsiveness for shock absorption due to valve opening operation. The present invention aims to solve the above problems. (Means for Solving the Problems) According to the present invention, a spool valve for anti-nose diving and an annular disc pulp are interposed in the passage of hydraulic oil flowing from the oil chamber to the oil reservoir chamber in the pressure side stroke. The disc valve into which the anti-nose dive spool valve is fitted is movably provided via a relief spring. Attach one end of the link lever with the brake caliper attached to 70
The link lever is rotatably supported on the front fork body side, and the other end of the link lever is pivotally supported via an elastic body in a long hole formed on the front fork body side, so that the swinging end of the link lever can be rotated into an anti-nose position during braking. A spool valve for diving is connected so as to enter an annular disc valve, and the swinging displacement of this link lever corresponding to the braking torque of the brake caliper is transmitted to the spool pulp for anti-nose diving. With this structure, the link lever that supports the brake caliper moves while compressing the elastic body due to the braking torque, but the reaction force of the braking torque applied to the brake caliper is absorbed by the elastic body fitted into the long hole on the front fork body. , so braking torque is not directly applied to the anti-nose dive spool valve. That is, since the movement of the brake caliper is only transmitted as a signal to the spool valve for anti-nose diving, the required strength of the spool valve for anti-nose diving can be reduced. In addition, the spool valve for anti-nose dives does not get pushed back when it is pushed up from the road surface while braking, and only the disc valve senses the internal pressure and opens, so such shocks can be absorbed by small movable members with good response. In addition to absorbing and relaxing the brake, the disc brake caliper and link lever do not move, ensuring stable brake operation. (Example) Hereinafter, an example of the present invention will be described based on the accompanying drawings. An inner tube 3 connected to the vehicle body side is slidably housed in an outer tube 2 supporting an axle, and a seat pipe 4 is positioned inside the inner tube 3 and erected on the outer tube 2. An upper oil chamber A that expands during the compression stroke is defined between the inner tube 3 and the seat pipe 4, and a lower oil chamber B that also contracts during the compression stroke is defined between the outer tube 2 and the seat pipe 4. is defined at the tip of the inner tube 3, which applies resistance to the hydraulic oil flowing from oil chamber A to oil chamber B during the rebound stroke and generates a damping force on the rebound side, and conversely, during the compression stroke. A damping pulp 5 is provided that allows hydraulic oil to flow smoothly from B to A. A piston part 6 inscribed in the inner tube 3 is integrally provided at the upper end of the seat pipe 4, and the piston part 6 communicates with each other from the inside of the seat pipe 4 to the upper inside of the inner tube 3, and a part of the piston part 6 is filled with a gas. An oil reservoir chamber C is formed. Note that a tapered cylindrical oil hole rod 5 is provided at the base of the seat pipe 4.
0 is fitted, and an oil lock is performed at the most inserted position of the inner tube 3. The oil hole rod 50 opens during the extension stroke and guides the hydraulic oil in the oil reservoir chamber C to the lower oil chamber B. At the bottom of the outer tube 2, there are a lower oil chamber B and an oil reservoir chamber C.
A spool pulp 8 for anti-nose diving and an annular disk pulp 15 are interposed between the passages 7a and 7b. The spool pulp 8 for anti-nose diving is slidably housed in a pulp housing 10 attached to the lower part of the outer tube 2 via an end plate 11, and a valve body part 12 protruding annularly at the tip thereof. is formed, and a return spring 17 is seated inside the valve body portion 12 to bias it in the opening direction. In the pulp housing 10, an annular disc pulp 15 is slidably housed, which the valve body g12 covers while maintaining a desired gap.The pulp housing 10 has a ring 20 for positioning the disc pulp 15. At the same time, a relief spring 18 that constantly biases the disc pulp 15 is interposed. While the anti-nose dive pool pulp 8 is pushed against the return spring 17, the flow of hydraulic oil from the passage 7a to the passage 7b occurs between the outer periphery of the valve body 12 and the inner periphery of the disc pulp 15. This reduces the damping force on the compression side. Next, a bracket 26 is attached to the lower part of the outer tube 2.
A brake caliper 32 is attached to the link lever 30, with the lower end of the link lever 30 rotatably supported on the bracket 26 via a pin 31. A bracket 27 is integrally protruded from the side of the outer tube 2, and a long hole 28 is formed in the bracket 27. Two elastic bodies made of, for example, a rubber material are fitted into the inside of the long hole 28. It will be done. A pin 33 is fixed to the upper end of the link lever 30, and this pin 33 is pivotally supported in the elongated hole 28 via an elastic body 29. Because of this, the upper end of the link lever 30 can move by a slight distance within the elongated hole 28 without compressing the elastic body 29 via the pin 33, and the brake caliper 32 can swing around the pin 31 on the outer tube. The link lever 30 is integrally formed with an arm portion 35 that projects, and a bushing rod 36 is screwed onto the tip of the arm portion 35, and this bushing rod 36 is attached to the base of the spool pulp 8 for anti-nose diving. The anti-nose dive spool pulp 8 is pushed into operation as the link lever 30 swings when it comes into contact with the end of the bushing rod 36. Note that a lock nut 40 is attached to the upper end of the bushing rod 36.
are screwed together, and a rubber boot 41 is attached to the upper end of the pulp housing 10 so as to cover the bush rod 36. The brake disc 37 rotates integrally with a wheel (not shown), and rotates clockwise as shown by an arrow in the figure. During braking, the brake caliper 32 clamps the brake disc 37 with pads (not shown) to restrain rotation and apply braking force. Therefore, during braking, a braking torque in the rotational direction of the brake disc 37 is applied to the brake caliper 32, causing the link lever 30 to rotate clockwise in the figure. The dive spool pulp 8 is pushed in. It is constructed as described above, and its operation will be explained next. During normal running, the anti-nose dive spool pulp 8 is fully opened by the biasing force of the return spring 17, as shown in the figure. Therefore, in the pressure side stroke, the hydraulic oil corresponding to the entering volume of the inner tube 3 is transferred from the lower oil chamber B to the passage 7a,
The oil flows into the oil sump chamber C through the pulp housing 10 and the passage 7b. During this process, the anti-nose dive spool pulp 8 is fully opened, so it provides almost no resistance to the flow of hydraulic oil, and the front 7 orifices absorb pressure-side vibrations to maintain a soft bundled feel. In addition, in the extension stroke, resistance is applied to the hydraulic oil flowing from the upper oil chamber A to the lower oil chamber B via the damping pulp 5, and a predetermined damping force is generated. During this extension stroke, when the oil chamber B, which serves as the expansion chamber, suddenly becomes negative pressure, the oil hole rod 50 opens and the oil spool chamber C directly flows from the oil reservoir chamber C to the oil chamber B without passing through the anti-nose dive spool pulp 8. As a result, hydraulic oil is sucked in, and the oil hole rod 50 functions as a check valve. On the other hand, during deceleration braking, the brake caliper 32 restrains the rotation of the brake disc 37, and the brake caliper 32 attempts to rotate clockwise in the figure together with the link lever 30 due to this braking torque. As a result, the link lever 30 rotates while compressing the elastic body 29, pushes the anti-nose dive spool pulp 8 through the arm portion 35 and the bushing rod 36, and fits the valve body portion 12 into the annular disc pulp i5. Match. As a result, with deceleration braking, the 70-ton 7-year-old sinks and the hydraulic oil in oil chamber B attempts to flow into oil reservoir chamber C, but the anti-nose dive spool pulp 8 and By fitting the disc pulp 15, the passage 7a
The flow of the hydraulic oil from the inner tube 3 toward the passage 7b is restricted, and the entry of the inner tube 3 is restricted, which means that the front 7 is prevented from sinking. At this time, the link lever 30 rotates while compressing the elastic body 29 by the braking torque generated by the brake caliper 32, and the circular arc movement of the arm portion 35 is transferred to the linear movement of the anti-nose dive spool pulp 8 via the bushing rod 36. Convert smoothly to . That is, while conventionally the movement of the brake caliper was regulated by the valve closing operation in which the anti-nose die pulp sits on the valve seat, the present invention uses a long hole formed in the front fork body 1 (outer tube 2). It is regulated and supported by an elastic body 29 fitted to 28. Therefore, the anti-nose dive spool pulp 8 is directly connected to the brake caliper 3 via the link lever 30.
Although the anti-nose dive spool pulp 8 is driven by the braking torque of the brake caliper 32, the displacement corresponding to the braking torque of the brake caliper 32 is only transmitted as a signal. No structural strength is required to support the 70-ton body side (outer tube 2). When the anti-nose dive spool pulp 8 and the disc pulp 15 are restricting the flow of hydraulic oil on the pressure side during the above-mentioned braking, if the wheel pushes up due to unevenness from the road surface, the oil chamber B applied to the disc pulp 15 will As the pressure increases, the disc pulp 15 separates from the valve body 12 while compressing the I/N 7 spring 18, thereby relieving the pressure-side hydraulic oil. Since the valve opening pressure of this disc pulp 15 is determined by the amount of displacement of the anti-nose dive spool pulp 8 in proportion to the braking torque, it is possible to effectively absorb the impact at the time of pushing up, which is larger than the sinking due to braking. , it is possible to prevent discomfort from being caused to the driver. In this way, when the pressure side hydraulic oil is relieved during braking, the anti-nose dive spool pulp 8 is in a pressure balanced state and does not push back the brake caliper 32 to move it, thereby ensuring stable braking operation. In addition, spool valve 8 for anti-nose dive during braking.
The compression side damping force provided by the disc pulp 15 can be easily adjusted by adjusting the fitting gap with the disc pulp 15, and the relief pressure of the disc pulp 15 can be easily adjusted by changing the amount of penetration by adjusting the screwing position of the bushing rod 36. (Effects of the Invention) As described above, the present invention pivots one end of the link lever to which the brake caliper is attached to a long hole formed in the front fork via an elastic body, and the swinging end of the link lever is rotated during braking. Relief 8 spool valve for anti-nose dive! Since the spool valve for anti-7-zugip is connected so that it can enter the annular disc pulp that has the function, the braking torque is received by the elastic body, and the braking force is simply input as a displacement signal. Not only is structural strength not required to support the movement of the brake caliper, that is, the braking torque, but also when the pressure side hydraulic oil is drained due to the thrust of the wheel during braking, the mass of the movable parts is small, so the response is good, and the brake Since no thrust force is transmitted to the caliper to displace the disc in the opposite direction, stable braking operation is ensured. BRIEF DESCRIPTION OF THE DRAWINGS The drawing is a side sectional view showing one embodiment of the present invention. 2... Outer tube, 8... Spool valve for anti-nose dive, 15... Disc pulp, 17
...Return spring, 18...Relief spring, 28...Long hole, 29...Elastic body, 30...
Link lever, 32... Brake caliper, 33...
・Pin, 35... Arm part, 36... Butsch rod (1 person outside)

Claims (1)

[Claims] An anti-nose dive valve is installed in the passage of hydraulic oil flowing from the oil chamber to the oil reservoir chamber in the pressure side stroke, and the valve seat on which the anti-nose dive valve is seated is movable via a relief spring, while the brake caliper One end of the link lever with the attached link lever is rotatably supported on the front fork body side, and the other end of the link lever is pivotally supported on the front fork body side via an elastic body, and the swinging end of the link lever is braked. A front fork sinking prevention device characterized by an anti-nose dive valve that is connected so that it closes when the anti-nose dive valve closes.