JP3719538B2 - Front forks such as motorcycles - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a front fork such as a motorcycle having an improved oil lock mechanism.
[0002]
[Prior art]
In the front fork of a motorcycle, an oil lock collar 3 is installed at the tip of the inner tube 2 and an oil lock piece 5 is installed at the bottom of the outer tube 4 as described in Japanese Utility Model Publication No. 2-44119 shown in FIG. And the oil lock collar 3 is fitted to the oil lock piece 5 to form the oil lock chamber 6 when the front fork 1 is compressed most, and further compression of the inner tube 2 is stopped.
[0003]
Further, in the front fork 10 as described in Japanese Utility Model Publication No. 56-119789 shown in FIG. 4, a hollow pipe 14 having an enlarged diameter portion 13 is erected on the bottom of the outer tube 11, and the inner tube 12 The piston 15 installed at the distal end of the pipe divides the oil chamber on the outer periphery of the hollow pipe 14 into an upper oil chamber 16 and a lower oil chamber 17, and the hollow pipe 14 is connected to the reservoir chamber 18 in the hollow pipe 14. A first oil hole 19 that communicates with the lower oil chamber 17 is formed, and a second oil hole 20 that communicates between the reservoir chamber 18 and the upper oil chamber 16 is formed.
[0004]
In the compression process of the front fork 10, the working oil in the lower oil chamber 17 flows into the reservoir chamber 18 through the first oil hole 19, and a compression-side damping force is generated. When the front fork 10 is compressed most, the piston 15 of the inner tube 12 closes the first oil hole 19 and the lower oil chamber 17 becomes an oil lock chamber, and further compression of the inner tube 12 is stopped.
[0005]
[Problems to be solved by the invention]
However, in the front fork 1 shown in FIG. 3, the oil lock piece 5 is required for the outer tube 4, and this oil lock piece 5 is connected to the oil lock collar 3 and the shaft in order to prevent a galling phenomenon with the oil lock collar 3. High machining accuracy and assembly accuracy are required, such as matching the hearts.
[0006]
Further, in the front fork 10 shown in FIG. 4, a check valve 21 that is opened in the compression process of the front fork 10 is installed in the diameter-expanded portion 13 of the hollow pipe 14. The hydraulic oil in the reservoir chamber 18 flows into the upper oil chamber 16 through the check valve 21 and further through the second oil hole 20. Although the negative pressure in the upper oil chamber 16 is eliminated by the inflow of the hydraulic oil, since the inflow of the hydraulic oil is based only on the negative pressure in the upper oil chamber 16, the amount of the inflow hydraulic oil may be insufficient. Yes, there is a possibility that the negative pressure of the upper oil chamber 16 during the compression process of the front fork 10 cannot be satisfactorily implemented.
[0007]
An object of the present invention is made in consideration of the above-described circumstances, and can provide an oil lock mechanism having a simple and inexpensive structure, and can satisfactorily eliminate the negative pressure in the upper oil chamber during the compression process of the front fork. It is to provide a front fork such as a motorcycle.
[0008]
[Means for Solving the Problems]
According to the first aspect of the present invention, the inner tube connected to the vehicle body slides in the outer tube connected to the axle side, and the diameter-enlarged portion that is in sliding contact with the inner periphery of the inner tube is formed on the bottom of the outer tube. A hollow pipe is provided, and a piston that divides an oil chamber outside the hollow pipe into an upper oil chamber and a lower oil chamber is installed on the inner periphery of the tip of the inner tube, and a reservoir chamber is provided inside the hollow pipe. The hollow pipe has a front fork such as a two-wheeled vehicle in which an oil hole communicating the reservoir chamber and the lower oil chamber is formed, and the hollow pipe is formed between the inner periphery of the piston and the outer periphery of the hollow pipe. An annular flow path that communicates the upper oil chamber and the lower oil chamber is formed in the piston, and a piston hole that allows the upper oil chamber and the lower oil chamber to communicate with each other is formed in the piston. A check valve that opens the piston hole in the compression process of the front fork is disposed on the piston hole side of the stone, and a disk valve is disposed on the lower surface side of the piston so as to face the opening of the piston hole through a gap, The disk valve is bent and deformed when the front fork is compressed most and closes the opening of the piston hole.
[0009]
According to a second aspect of the present invention, in the first aspect of the invention, the disc valve is configured such that the outer peripheral end thereof is fixed and the inner peripheral end side thereof is deformable.
[0010]
The invention described in claims 1 and 2 has the following effects.
The disc valve is configured to be able to close the piston hole of the piston installed at the tip of the inner tube, and this disc valve functions as a conventional oil lock piece installed at the bottom of the outer tube. Since this disc valve is simpler and less expensive than a conventional oil lock piece, an oil lock mechanism having a simple and inexpensive structure can be provided.
[0011]
Further, in the compression process of the front fork, the piston hole of the piston disposed at the tip of the inner tube and the check valve in the valve open state are passed through an annular flow path between the piston inner periphery and the hollow pipe outer periphery. The hydraulic oil in the lower oil chamber is guided to the upper oil chamber. As described above, since the hydraulic oil actively flows into the upper oil chamber from the lower oil chamber whose volume decreases during the compression process of the front fork through the piston hole and the annular flow path, A sufficient amount of hydraulic fluid is introduced. As a result, the negative pressure in the upper oil chamber during the compression process of the front fork can be satisfactorily eliminated.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a substantially entire longitudinal sectional view showing one embodiment of a front fork such as a motorcycle according to the present invention. FIG. 2 is an enlarged cross-sectional view showing a part of FIG.
[0013]
A front fork 30 shown in FIG. 1 is an upright front fork, and an inner tube 32 is slidably inserted into an outer tube 31, and a suspension spring 33 and a hollow pipe that functions as a damper are provided between the tubes 31 and 32. 34 is arranged. An axle (not shown) is supported in the axle hole 35 of the outer tube 31, and the inner tube 32 is connected to a vehicle body frame (not shown).
[0014]
The hollow pipe 34 is fixed to the bottom portion 36 of the outer tube 31 in a standing state using a center bolt 37. On the distal end side of the hollow pipe 34, a ring body 38 is fitted and a diameter-expanded portion 39 that is in sliding contact with the inner peripheral surface of the inner tube 32 is integrally formed.
[0015]
The suspension spring 33 has a lower end supported by the enlarged diameter portion 39 of the hollow pipe 34, and an upper end supported by a fork cap (not shown) screwed to the upper end of the inner tube 32, from the road surface. To absorb the shock of.
[0016]
The front fork 30 is filled with hydraulic oil in the outer tube 31 and the inner tube 32, and the interior of the hollow pipe 34 is defined as a reservoir chamber 40. Here, the code | symbol 41 in FIG. 1 shows an oil surface. A piston 42 is installed at the lower end of the inner tube 32, and the piston 42 divides the oil chamber outside the hollow pipe 34 into an upper oil chamber 43 and a lower oil chamber 44.
[0017]
The hollow pipe 34 has a first oil hole 45 communicating with the reservoir chamber 40 and the lower oil chamber 44 at a lower portion thereof, and a second oil hole communicating with the reservoir chamber 40 and the upper oil chamber 43 at an upper portion thereof. 46 is established. A plurality of the first oil holes 45 and the second oil holes 46 are formed along the axial direction of the hollow pipe 34. As will be described later, the damping force generated in the first oil hole 45 and the second oil hole 46 suppresses the contraction movement of the outer tube 31 and the inner tube 32 that occurs due to the absorption of the impact force by the suspension spring 33. .
[0018]
As shown in FIG. 2, a plurality of piston holes 47 that allow the upper oil chamber 43 and the lower oil chamber 44 to communicate with each other are formed in the piston 42, and a check valve 48 is formed on the upper surface side of the piston 42. Is disposed. The check valve 48 includes a ring-shaped valve main body 48A and valve protrusions 48B protruding from a side surface of the valve main body 48A at a predetermined interval in the circumferential direction. A valve protrusion 48B of the check valve 48 is supported by a valve stopper 50 locked to the inner tube 32 via a valve spring 49. The check valve 48 holds the piston hole 47 in the closed state by the urging force of the valve spring 49, but in the compression process of the front fork 30, the check valve 48 is opened by the pressure of the hydraulic oil flowing through the piston hole 47. The upper end opening 47A of the piston hole 47 is opened.
[0019]
On the other hand, on the lower surface side of the piston 42, the disk valve 52 is disposed through the gap 51 so as to face the lower end opening 47 </ b> B of the piston hole 47. The disc valve 52 is clamped and fixed between the bent tip portion of the inner tube 32 and the piston 42 by using a shim 55 at the outer peripheral portion 53 thereof. And the inner peripheral part 54 of the disk valve 52 is comprised so that bending deformation is possible. When the front fork 30 is most compressed, the pressure in the lower oil chamber 44 is extremely increased as will be described later, and this pressure causes the inner peripheral portion 54 of the disk valve 52 to bend and deform, thereby closing the lower end opening 47B of the piston hole 47.
[0020]
In addition, an annular flow path 56 that connects the upper oil chamber 43 and the lower oil chamber 44 is formed between the inner peripheral surfaces of the piston 42 and the check valve 48 and the outer peripheral surface of the hollow pipe 34.
[0021]
Reference numeral 57 in FIG. 1 denotes a rebound spring, which abuts against the diameter-expanded portion 39 of the hollow pipe 34 when the front fork 30 is extended to absorb the shock at the time of maximum extension.
[0022]
Further, a bush 58 that guides the sliding of the outer tube 31 and the inner tube 32 is disposed on the inner periphery of the opening of the outer tube 31, and an oil seal 59 is mounted in the vicinity of the bush 58. The oil seal 59 is sandwiched between the outer tube 31 by a washer 60 and a stopper ring 61, and a dust seal 62 is further mounted adjacent to the oil seal 59.
[0023]
Next, the operation will be described.
In the compression process of the front fork 30, the check valve 48 is opened, and the hydraulic oil in the lower oil chamber 44 flows into the upper oil chamber 43 through the piston hole 47 of the piston 42. The hydraulic oil in the lower oil chamber 44 flows into the upper oil chamber 43 through the annular flow path 56 between the hollow pipe 34. Further, the hydraulic oil in the reservoir chamber 40 flows into the upper oil chamber 43 through the second oil hole 46. Due to the inflow of such hydraulic oil, the negative pressure in the upper oil chamber 43 whose volume is increased is eliminated.
[0024]
Further, in the compression process of the front fork 30, the inner tube 32 enters into the lower oil chambers 43 and 44 on the outer periphery of the hollow pipe 34, and hydraulic oil corresponding to the intrusion volume passes through the first oil hole 45. It flows into the reservoir chamber 40. A damping force on the compression side is generated by the resistance while the hydraulic oil passes through the first oil hole 45.
[0025]
In the compression process of the front fork 30, the plurality of first oil holes 45 are gradually closed by the piston 42, and when the front fork 30 is most compressed, the piston 42 closes the first oil hole 45 positioned at the lowest position. At this time, the pressure in the lower oil chamber 44 is extremely increased, the disk valve 52 is bent and deformed, and the piston hole 47 of the piston 42 is closed. As a result, the hydraulic oil in the lower oil chamber 44 is almost trapped, and the lower oil chamber 44 becomes an oil lock chamber, and further compression of the inner tube 32 is stopped. By the oil lock action of the oil lock chamber, collision between the lower end portion of the inner tube 32 and the bottom portion 36 of the outer tube 31 is avoided.
[0026]
Here, at the time of the oil lock, the hydraulic oil in the lower oil chamber 44 as the oil lock chamber flows into the upper oil chamber 43 only through the annular flow path 56 between the piston 42 and the hollow pipe 34. The impact of the front fork 30 at the time of maximum compression is alleviated.
[0027]
On the other hand, during the extension process of the front fork 30, the check valve 48 closes the piston hole 47 of the piston 42, so that the hydraulic oil in the upper oil chamber 43 flows into the reservoir chamber 40 through the second oil hole 46. Further, the hydraulic oil in the upper oil chamber 43 flows into the piston lower oil chamber 44 through the annular flow path 45 of the piston 42 and the check valve 48 and the hollow pipe 34. The extension side damping force is generated by the resistance of the hydraulic oil flowing through the second oil hole 46 and the annular flow path 56.
[0028]
In the extension process of the front fork 30, the inner tube 32 is withdrawn from the upper oil chamber 43, and hydraulic oil corresponding to the withdrawing volume flows into the lower oil chamber 44 from the reservoir chamber 40 through the first oil hole 45. The negative pressure in the lower oil chamber 44 is eliminated.
[0029]
When the front fork 30 is extended from the most compressed state, the bending deformation of the disc valve 52 is released, but since the check valve 48 closes the piston flow path 47 of the piston 42, the hydraulic oil in the piston 42 is checked. It flows into the lower oil chamber 44 as an oil lock chamber through the valve 48 and the annular flow path 56 of the piston 42 and the hollow pipe 34, and the negative pressure in the lower oil chamber 44 is eliminated.
[0030]
According to the above embodiment, the disc valve 52 is configured to be able to close the piston hole 47 of the piston 42 installed at the tip of the inner tube 32, and this disc valve 52 is installed at the bottom 36 of the outer tube 31. It functions as a conventional oil lock piece 5 (FIG. 3). Since the disc valve 52 is simple and inexpensive compared to the conventional oil lock piece 5 (FIG. 3), an oil lock mechanism having a simple and inexpensive structure can be provided.
[0031]
In the compression process of the front fork 30, the piston hole 47 of the piston 42 disposed at the tip of the inner tube 32 and the outer periphery of the check valve 48 in the valve-opened state are further passed, and further, the inner periphery of the piston 42 and the hollow pipe The hydraulic oil in the lower oil chamber 44 is guided to the upper oil chamber 43 through the annular flow path 56 between the outer periphery of the pipe 34, and the hydraulic oil is also supplied from the reservoir chamber 40 to the second oil hole of the hollow pipe 34. It is led into the upper oil chamber 43 through 46. As described above, hydraulic oil actively flows into the upper oil chamber 43 through the piston hole 47 and the annular flow channel 56 from the lower oil chamber 44 whose volume decreases in the compression process of the front fork. A sufficient amount of hydraulic oil is introduced into the upper oil chamber 43. As a result, the negative pressure in the upper oil chamber 43 during the compression process of the front fork 30 can be satisfactorily eliminated.
[0032]
In addition, the 2nd oil hole 46 can also be abbreviate | omitted by setting the annular flow path 56 of the check valve 48 and piston 42 inner periphery to an appropriate magnitude | size. In addition, although a plurality of first oil chambers 45 are described, a single oil chamber 45 may be provided.
[0033]
【The invention's effect】
As described above, according to the front fork of a motorcycle or the like according to the present invention, an oil lock mechanism having a simple and inexpensive structure can be provided, and the negative pressure in the upper oil chamber during the compression process of the front fork can be satisfactorily eliminated.
[Brief description of the drawings]
FIG. 1 is a substantially entire longitudinal sectional view showing an embodiment of a front fork such as a two-wheeled vehicle according to the present invention.
FIG. 2 is an enlarged cross-sectional view showing a part of FIG. 1 in an enlarged manner.
FIG. 3 is a partial cross-sectional view showing a conventional front fork.
FIG. 4 is a partial cross-sectional view showing another conventional front fork.
[Explanation of symbols]
30 Front fork 31 Outer tube 32 Inner tube 34 Hollow pipe 36 Bottom 39 Expanded portion 40 Reservoir chamber 42 Piston 43 Upper oil chamber 44 Lower oil chamber 45 First oil hole 46 Second oil hole 47 Piston hole 48 Check valve 47B Lower end opening 51 Clearance 52 Disc Valve 53 Disc Valve Outer Part 54 Disc Valve Inner Part 56 Annular Flow

Claims (2)

An inner tube connected to the vehicle body slides inside the outer tube connected to the axle side, and a hollow pipe provided with a diameter-enlarged portion slidably contacting the inner periphery of the inner tube is erected on the bottom of the outer tube.
A piston that divides the oil chamber outside the hollow pipe into an upper oil chamber and a lower oil chamber is installed on the inner periphery of the tip of the inner tube,
A reservoir chamber is defined inside the hollow pipe, and the hollow pipe has a front fork such as a two-wheeled vehicle in which an oil hole communicating the reservoir chamber and the lower oil chamber is formed.
An annular flow path is formed between the inner periphery of the piston and the outer periphery of the hollow pipe to communicate the upper oil chamber and the lower oil chamber,
The piston is formed with a piston hole that allows the upper oil chamber and the lower oil chamber to communicate with each other.
A check valve that opens the piston hole in the compression process of the front fork is arranged on the piston hole side of the piston,
A disk valve is disposed on the lower surface side of the piston so as to face the opening of the piston hole through a gap, and the disk valve is bent and deformed when the front fork is compressed to close the opening of the piston hole. Front forks such as motorcycles. The front fork of a two-wheeled vehicle or the like according to claim 1, wherein the outer peripheral end of the disc valve is fixed and the inner peripheral end side thereof can be bent and deformed.

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