JP2015161397A - Upright front fork and wheel suspension device with upright front fork - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an upright front fork capable of increasing a responsiveness of air reaction force against a compression stroke and an extension stroke.SOLUTION: This invention relates to an upright front fork 1 including an attenuation force generating mechanism for generating attenuation force by a flow resistance of oil as an outer tube 2 and an inner tube 3 are extended or retracted by supporting the inner tube 3 in an upward or downward slidable manner by guide bushes 4, 5 fitted to an upper part and a lower part of an inner circumference of the outer tube 2, filling oil inside of each of the outer tube 2 and the inner tube 3 to form an air chamber Sa at the upper part within the inner tube 3. The side wall of the inner tube 3 is formed with a lateral hole 21 for communicating an annular clearance Sδ defined by the outer tube 2 and the inner tube 3 as well as the upper and lower guide bushes 4, 5 with the inside of the inner tube 3.

Description

  The present invention relates to an upright front fork that suspends a front wheel of a motorcycle or the like with respect to a vehicle body and a wheel suspension device including the upright front fork.

  For example, a front wheel of a motorcycle is suspended from a vehicle body by a wheel suspension device composed of a pair of left and right front forks. The front fork constituting the wheel suspension device is of an upright type or an inverted type. (For example, see Patent Documents 1 and 2). An example of a conventional upright front fork is shown in FIG.

  7 is a half-sectional view of a conventional upright front fork. In the illustrated upright front fork 101, a part of the inner tube 103 on the vehicle body side is located inside the outer tube 102 on the axle side. The inner tube 103 is slidably supported by guide bushes 104 and 105 which are inserted from above and fitted on the inner periphery of the outer tube 102. A seat pipe 110 is planted concentrically at the bottom of the outer tube 102, and a piston 110A formed integrally with the upper end of the seat pipe 110 is a piston ring 112 fitted on the outer periphery thereof. And is in sliding contact with the inner periphery of the inner tube 103. A suspension spring 114 is interposed between the inner tube 103 and the seat pipe 110, and a check valve 116, which constitutes a damping force generation mechanism, is provided at the inner periphery of the lower portion (tip) of the inner tube 103. 117 is fixed.

  Furthermore, oil is sealed in oil chambers S1, S2, and S3 formed inside the outer tube 102 and the inner tube 103, and an air chamber Sa is formed in the upper portion of the inner tube 103. The air chamber Sa is filled with air.

  According to such an upright front fork 101, for example, when the front wheel moves up and down following the road surface irregularities while the motorcycle is running, the outer tube 102 and the inner tube 103 expand and contract. The shock received by the front wheels from the road surface is absorbed and relaxed by the spring reaction force due to the expansion and contraction of the suspension spring 114 accompanying the expansion and contraction and the damping force generated by the oil flow resistance, thereby improving the riding comfort of the motorcycle.

Japanese Patent Application No. 2012-247909 JP 2005-308196 A

  By the way, in the fixed fitting type upright front fork 101 in which the guide bushes 104 and 105 are fitted on the upper and lower sides of the inner periphery of the outer tube 102, as shown in FIG. Although air inevitably remains in the annular gap Sδ defined by the tube 102 and the inner tube 103, in the conventional upright front fork 101, the annular gap Sδ is sealed, and the air remaining therein is annular. The following problem has occurred because of being confined in the space Sδ.

  That is, when the upright front fork 101 shifts from the neutral state shown in FIG. 8A to the compression stroke shown in FIG. 8B, the oil in the oil chambers S1 and S2 is compressed and its pressure is increased, The air in the chamber Sa is, as shown in black in FIG. 8B, the volume of entry of the inner tube 103 into the oil chamber S2 (cross-sectional area of the inner tube 103 (area surrounded by the outer diameter) × stroke) ) And the volume is reduced. At this time, since the annular gap Sδ is sealed as described above, the pressure in the oil chamber S1 does not immediately propagate to the annular gap Sδ, and the air in the annular gap Sδ is not compressed and is black in FIG. Since it is in an uncompressed state as shown by painting, a response delay occurs in the reaction force caused by air, and the compression reaction force in the middle stroke region is indicated by a solid curve A as shown by a dashed curve a in FIG. There arises a problem that it becomes harder than the above characteristics and feels hardness. Here, FIG. 9 is a diagram showing the air reaction force characteristics with respect to the stroke, where the horizontal axis represents the stroke and the vertical axis represents the air reaction force.

  Thus, at the end of the compression stroke, the pressure in the oil chamber S1 propagates through the slight clearance to the annular clearance Sδ, so that the air in the annular clearance Sδ is also compressed and blackened in FIG. As shown, the volume also decreases, but when the state shifts to the expansion stroke, the oil pressure in the oil chamber S1 decreases, and the air in the air chamber Sa is retracted from the oil chamber S2 in the inner tube 103. It expands by the amount of (the cross-sectional area of the inner tube 103 (area surrounded by the outer diameter) × stroke), and its volume increases as shown in black in FIG. At this time, since the annular gap Sδ is sealed, the pressure in the oil chamber S1 does not immediately propagate to the annular gap Sδ, and the air in the annular gap Sδ does not expand as indicated by black coating in FIG. In the non-expanded state (the state at the end of the compression stroke), a response delay occurs in the air reaction force, and the elongation reaction force is shown by the solid curve B in FIG. Therefore, there is a problem that the driving stability of the vehicle is impaired.

  The present invention has been made in view of the above problems, and an object thereof is to provide an upright front fork capable of enhancing the responsiveness of air reaction force to compression and extension strokes and a wheel suspension device including the upright front fork. There is to do.

In order to achieve the above object, the invention according to claim 1 is a guide in which a part of the inner tube on the vehicle body side is inserted from above into the outer tube on the axle side, and is fitted on the upper and lower sides of the inner periphery of the outer tube. The inner tube is supported by the bush so as to be vertically slidable, and a suspension spring is interposed between the outer tube and the inner tube,
Oil is enclosed in the outer tube and the inner tube to form an air chamber in the upper portion of the inner tube, and a damping force is generated by the flow resistance of the oil accompanying expansion and contraction of the outer tube and the inner tube. In an upright front fork equipped with a damping force generation mechanism that
A lateral hole is formed in a side wall of the inner tube so as to communicate an annular gap defined by the outer tube, the inner tube, and the upper and lower guide bushes with the inside of the inner tube.

According to a second aspect of the present invention, in the first aspect of the invention, the inner tube is supported by the guide bushes fitted vertically in the outer tube so as to be slidable vertically, and the inner periphery of the lower end of the inner tube A part of the damping force generation mechanism
A lateral hole of the inner tube is formed at a position above the lower guide bush on the inner periphery of the outer tube.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, a distance collar is provided between the upper and lower guide bushes in the annular gap.

A wheel suspension device according to claim 4 is a device for suspending a wheel with the erecting front fork according to any one of claims 1 to 3 and another erecting front fork paired therewith,
The another upright front fork is configured not to include the suspension spring and the damping force generation mechanism of the upright front fork according to any one of claims 1 to 3.

  According to the first aspect of the invention, since the annular gap communicates with the inside of the inner tube by the lateral hole formed in the side wall of the inner tube, the pressure (hydraulic pressure) change in the inner tube in the compression stroke and the extension stroke is annular. The air that immediately propagates to the gap and the air remaining in the annular gap immediately compresses / expands without being sent in time, and the response of the air reaction force to the compression and extension strokes can be enhanced. Further, since the air remaining in the annular gap is discharged from the lateral hole formed in the side wall of the inner tube to the outside of the annular gap, the amount in the annular gap is reduced. Responsiveness of the air reaction force to the extension stroke is enhanced.

  According to the second aspect of the present invention, the horizontal hole is formed at a position above the lower guide bush on the inner periphery of the outer tube, and the horizontal hole is positioned at a position of a check valve or the like that constitutes a part of the damping force generation mechanism. Even if is opened, since the damping force is closed by the guide bush, the influence of the lateral hole on the damping force can be suppressed to a small level.

  According to the third aspect of the present invention, since the distance collar interposed between the upper and lower guide bushes in the annular gap can reduce the amount of air remaining in the annular gap by the volume of the distance collar, The problem of the delay in the response of the air reaction force due to the air remaining in the air can be solved more reliably.

  According to the fourth aspect of the present invention, one of the pair of upright front forks constituting the wheel suspension device is configured with a simple and inexpensive structure (not including a suspension spring and a damping force generation mechanism). The structure of the wheel suspension device can be simplified and the cost can be reduced.

It is a half-year-old sectional view of an upright front fork according to Embodiment 1 of the present invention. It is the X section enlarged detail drawing of FIG. (A)-(c) is a figure which shows the volume change of the air in the erecting front fork which concerns on Embodiment 1 of this invention. It is a half cut sectional view of the formation type front fork principal part concerning Embodiment 2 of the present invention. FIG. 4 is a half-cut sectional view of one of the pair of front forks (upright oil sliding front fork) constituting the wheel suspension device according to the first embodiment of the present invention. It is a half-cut sectional view of one (upright type grease sliding front fork) of a pair of front forks constituting the wheel suspension device according to the second embodiment of the present invention. It is a half cut sectional view of the conventional upright front fork. (A)-(d) is a figure which shows the volume change of the air in the conventional upright front fork. It is a figure which compares and shows the characteristic of the air reaction force with respect to the stroke in this invention and the conventional upright front fork.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
[Erecting front fork]
<Embodiment 1>
1 is a semi-year-old cross-sectional view of an upright front fork according to Embodiment 1 of the present invention, FIG. 2 is an enlarged detail view of a portion X in FIG. 1, and the upright front fork 1 shown in FIG. A front wheel (not shown) is suspended from the vehicle body. In the upright front fork 1, as shown in FIG. 1, a part of the inner tube 3 on the vehicle body side is inserted into the outer tube 2 on the axle side from above, and the upper and lower sides of the inner periphery of the outer tube 2 are The inner tube 3 is supported by the ring-shaped guide bushes 4 and 5 fitted to the upper and lower slidable parts. The lower end portion of the outer tube 2 is attached to the front wheel by an axle (not shown) inserted through a shaft hole 2a formed in the outer tube 2, and the upper end portion of the inner tube 3 is fitted to the upper and lower portions of the upper portion thereof. It is attached to the vehicle body via an upper bracket and a lower bracket (not shown).

  Here, an oil seal 6 is fitted on the inner periphery of the portion of the upper end opening of the outer tube 2 where the inner tube 3 is inserted, and the lip portion is disposed on the outer periphery of the upper end of the outer tube 2. A dust seal 7 slidably contacting the outer periphery of the tube 3 is fitted. Oil leakage from the inside of the upright front fork 1 is prevented by the sealing action of the oil seal 6, and upright type by the sealing action of the dust seal 7. Intrusion of dust into the front fork 1 is prevented.

  The upper guide bush 4 is disposed below the oil seal 6 at the upper end portion of the outer tube 2, and the guide bush 4 is a ring-shaped pipe guide that is fitted to the inner periphery of the upper end portion of the outer tube 2. 8 is held. The lower guide bush 5 is fitted to the middle portion of the outer tube 2 in the vertical direction.

  By the way, the upper end opening of the inner tube 3 is closed by a cap 9 fitted on the inner periphery thereof, and a seat pipe 10 whose upper end is opened is fastened to the bottom of the outer tube 2 by bolts 11. Has been planted concentrically. A flange-like piston 10A formed integrally with the upper end of the seat pipe 10 is in sliding contact with the inner periphery of the inner tube 3 via a piston ring 12 fitted on the outer periphery thereof. A bottomed cylindrical oil lock piece 13 is fitted to the outer periphery of the lower end. A suspension spring 14 is interposed between the upper end of the seat pipe 10 in the inner tube 3 and the cap 9. The oil lock piece 13 has an upper half outer periphery that is tapered (tapered) so as to reduce in diameter upward.

  A cylindrical oil lock collar 15 is fitted on the inner periphery of the lower end (tip) of the inner tube 3, and check valves 16, 17 are placed above and below the oil lock collar 15. Are provided. The check valve 16 has a function of opening at the compression stroke and closing at the expansion stroke, and the check valve 17 is opened at the time of shifting from an oil lock state to be described later to the expansion stroke, and a function of releasing the oil lock state. It is what has.

  Thus, oil chambers S1, S2, S3 are defined inside the outer tube 2 and the inner tube 3, and oil is sealed in these oil chambers S1 to S3. Further, an air chamber Sa partitioned by oil is formed in the upper portion of the inner tube 3, and the air chamber Sa is filled with air. An annular gap Sδ defined by the upper and lower guide bushes 4 and 5 is formed between the outer tube 2 and the inner tube 3, and oil is sealed in the annular gap Sδ. Some air remains. A rebound spring 18 is accommodated in the oil chamber S3.

  By the way, one or more oil holes 19 (only one is shown in FIG. 1) for communicating the oil chamber S1 and the oil chamber S3 are formed in the side wall of the upper end portion of the seat pipe 10. One or more oil holes 20 (only one is shown in FIG. 1) are formed in a lower portion of 10 (immediately above the oil lock piece 13) to communicate the oil chamber S1 and the oil chamber S2. The oil holes 19 and 20 and the check valves 16 and 17 generate a damping force that generates a required damping force by the flow resistance (flow loss) of the oil accompanying the expansion and contraction of the outer tube 2 and the inner tube 3. The mechanism is configured.

  Thus, in the upright front fork 1 according to the present embodiment, a lateral hole 21 is formed in the side wall of the inner tube 3 to communicate the annular gap Sδ and the oil chamber S1 in the inner tube 3. ing. Here, the lateral hole 21 is a position where the annular gap Sδ and the oil chamber S1 are always communicated regardless of the position of the inner tube 3, specifically, as shown in detail in FIG. It is formed in a position above the lower guide bush 5 fitted around the periphery.

  Next, the operation during the compression stroke and the expansion stroke of the upright front fork 1 configured as described above will be described with reference to FIG. Further, changes in the volume of air in the air chamber Sa and the annular gap Sδ during the compression stroke and the expansion stroke will be described below with reference to FIGS. 3 (a) to 3 (c). FIGS. 3A to 3C are views showing a change in the volume of air in the upright front fork. In FIG. 3, the portion occupied by air is shown in black.

1) Compression process:
When the front wheel moves up and down following the road surface unevenness while the motorcycle is running, the outer tube 2 and the inner tube 3 of the upright front fork 1 that suspends the front wheel expand and contract, but the inner tube 3 is moved to the outer tube 2. In the compression stroke that moves downward relative to the oil, the oil in the oil chamber S2 is compressed to increase its pressure, and a part of the oil in the oil chamber S2 passes through the check valves 17 and 16 to be oil. The oil flows into the chamber S3 and replenishes the oil corresponding to the increase in the volume of the oil chamber S3. A part of the oil in the oil chamber S1 flows into the oil chamber S3 through the oil holes 19 and 20, and passes through the oil holes 19 and 20 and the check valves 16 and 17 in this compression stroke. A desired damping force is generated by the flow resistance of the oil.

  By the way, in this compression stroke, the air in the air chamber Sa is compressed by the volume of entry into the oil chamber S2 of the inner tube 2 (cross-sectional area of the inner tube 3 (area surrounded by the outer diameter) × stroke), As shown in FIG. 3B, the volume is smaller than that in the neutral state shown in FIG. In the present embodiment, since the annular gap Sδ and the oil chamber S1 communicate with each other through the lateral hole 21 formed in the side wall of the inner tube 3, the oil pressure in the oil chamber S 1 is annular through the lateral hole 21. Air immediately propagates to the gap Sδ, and the air remaining in the annular gap Sδ is immediately compressed without a time delay. For this reason, the volume of residual air in the annular gap Sδ is smaller than the volume in the neutral state shown in FIG.

  As described above, in the compression stroke, the oil pressure in the oil chamber S2 is immediately propagated to the annular gap Sδ through the lateral hole 21, so that the responsiveness of the air reaction force to the compression stroke is improved, and the solid curve A in FIG. The desired air reaction force characteristics can be obtained as shown in Fig. 8, and the problem of feeling hardness due to an increase in the compression reaction force in the middle stroke area as in the past (see the broken curve a in Fig. 8) is solved. The Further, since the air remaining in the annular gap Sδ is discharged from the lateral hole 21 formed in the side wall of the inner tube 3 to the outside of the annular gap Sδ, the amount in the annular gap Sδ is reduced. As a result, the responsiveness of the air reaction force to the compression stroke is enhanced. In the present embodiment, the lateral hole 21 is formed in the outer chew at a position above the lower guide bush 5 of the inner circumference of the two, and the check valves 16 and 17 constituting a part of the damping force generating mechanism are provided. Even if the horizontal hole 21 is opened at the position, the damping pressure is blocked by the guide bush 5, so that the influence of the horizontal hole 21 on the damping force can be suppressed to a small value.

  When the oil lock collar 15 is fitted to the outer periphery of the oil lock piece 13 at the end of the compression stroke, a sealed space (oil lock chamber) is formed at the bottom of the outer tube 2 and an oil lock state is established. Therefore, the inner tube 3 is prevented from moving further downward, and the bottom of the inner tube 3 is prevented.

2) Extension process:
In the extension stroke in which the inner tube 3 moves upward relative to the outer tube 2, the volume of the oil chamber S2 increases, so that the oil pressure in the oil chamber S2 decreases, and a part of the oil in the oil chamber S1 flows. It flows into the oil chamber S2 through the oil hole 20. In this extension stroke, the volume of the oil chamber S3 decreases and the oil pressure in the oil chamber S3 increases. As described above, in the extension stroke, the check valve 16 passes from the oil chamber S2 to the oil chamber S3. In order to prevent this, a part of the oil in the oil chamber S3 flows into the oil chamber S1 through the oil hole 19. A required damping force is generated by the flow resistance when the oil passes through the oil holes 19 and 20 at this time.

  By the way, in this extension stroke, the air in the air chamber Sa is, as shown in FIG. 3C, the volume of the inner tube 3 withdrawing from the oil chamber S2 (the cross-sectional area of the inner tube 3 (enclosed by the outer diameter). Swelled by (area) x stroke). Further, in the present embodiment, since the annular gap Sδ and the oil chamber S1 communicate with each other through the lateral hole 21 formed in the side wall of the inner tube 3, the oil pressure in the oil chamber S1 is annularly communicated through the lateral hole 21. Air immediately propagates to the gap Sδ, and the air remaining in the annular gap Sδ immediately expands without time delay as shown in FIG. For this reason, the responsiveness of the air reaction force to the extension stroke is enhanced, and a desired air reaction force characteristic is obtained as shown by a solid curve B in FIG. 8, as in the conventional case (see the broken curve b in FIG. 8). Occurrence of a problem that the steering stability of the vehicle is impaired due to insufficient elongation reaction force is prevented.

  At the end of the extension stroke (when fully extended), the extension stroke of the inner tube 3 is regulated by the reband spring 18 provided in the oil chamber S3, and a check valve provided on the inner periphery of the lower end of the inner tube 3 17 and the oil lock collar 15 and the like are prevented from interfering with the piston 10A, and the impact at the time of full extension is mitigated to protect the parts from damage.

  As described above, according to the upright front fork 1 according to the present embodiment, the annular gap Sδ communicates with the oil chamber S1 in the inner tube 3 by the lateral hole 21 formed in the side wall of the inner tube 3. In the compression stroke and the extension stroke, the change in the oil pressure in the oil chamber S1 in the inner tube 3 is immediately transmitted to the annular gap Sδ through the lateral hole 21. For this reason, the air remaining in the annular gap Sδ is immediately compressed / expanded without time delay, and the responsiveness of the air reaction force to the compression and extension strokes is enhanced, and the optimum air reaction force characteristics for the compression and extension strokes. Is obtained.

  Further, since the oil can be circulated through the annular gap Sδ by the lateral hole 21 formed in the side wall of the inner tube 3, the sliding performance between the guide bushes 4, 5 and the inner tube 3 is achieved by the lubricating action of the circulating oil. The sliding resistance between the two can be kept low, and the durability of the guide bushes 4 and 5 can be increased.

<Embodiment 2>
Next, an upright front fork according to Embodiment 2 of the present invention will be described with reference to FIG.

  FIG. 4 is a half-cut sectional view of a main part of a formed front fork according to Embodiment 2 of the present invention. In this figure, the same elements as those shown in FIGS. In the following, a repetitive description thereof will be omitted.

  The upright front fork according to the present embodiment is characterized in that a cylindrical distance collar 22 is interposed between the upper and lower guide bushes 4 and 5 in the annular gap Sδ. This is the same as that of the upright front fork 1 according to the first embodiment.

Therefore, in the upright front fork according to the present embodiment, the same effect as in the first embodiment can be obtained. However, in this embodiment, the upper and lower guide bushes 4 and 5 in the annular gap Sδ. Since the distance collar 22 is interposed therebetween, the amount of air remaining in the annular gap Sδ can be reduced by the volume of the distance collar 22, and there is a problem of response delay of air reaction force caused by the air remaining in the annular gap Sδ. Can be solved more reliably.
[Wheel suspension]
Next, the wheel suspension apparatus according to the present invention will be described.

<Embodiment 1>
The wheel suspension apparatus according to the present embodiment is an upright oil sliding front fork 1 shown in FIG. 5 that is paired with the upright front fork 1 (see FIG. 1) according to the first or second embodiment. 'Is used to suspend the front wheel of the motorcycle from the vehicle body. Here, the configuration of the upright oil sliding front fork 1 'will be described below with reference to FIG.

  FIG. 5 is a half-sectional view of the upright oil sliding front fork. The illustrated upright oil sliding front fork 1 ′ includes a suspension spring 14 provided on the upright front fork 1 and the generation of damping force. This is a simple configuration with the mechanism (see FIG. 1) omitted.

  That is, in the illustrated upright oil sliding front fork 1 ′, a part of the vehicle body side inner tube 3 ′ is inserted from above into the axle side outer tube 2 ′. The inner tube 3 'is supported by the guide bushes 4' and 5 'fitted on the upper and lower sides of the circumference so as to be slidable in the vertical direction. The lower end portion of the outer tube 2 'is attached to the front wheel by an axle (not shown) inserted through a shaft hole 2a' formed in the outer tube 2 ', and the upper end portion of the inner tube 3' is fitted on the upper and lower sides thereof. It is attached to the vehicle body via an upper bracket and a lower bracket (not shown).

  Here, an oil seal 6 ′ and a dust seal 7 ′ whose lip portion is slidably in contact with the outer periphery of the inner tube 3 ′ are fitted to the outer periphery of the portion of the upper end opening of the outer tube 2 ′ where the inner tube 3 ′ is inserted. It is worn. Oil and air are sealed inside the outer tube 2 'and the inner tube 3', and an oil chamber S and an air chamber Sa are formed inside the outer tube 2 'and the inner tube 3'. Oil leakage in the oil chamber S is prevented by the sealing action of the oil seal 6 ′, and the dust action from the upper end opening of the outer tube 2 ′ is prevented by the sealing action of the dust seal 7 ′. It is peeling off. The upper end opening of the inner tube 3 'is closed by a cap 9' fitted on the inner periphery thereof.

  Thus, when the front wheel moves up and down following the road surface irregularities during traveling of the motorcycle, the viscous frictional resistance of the oil is applied to one of the upright oil sliding front forks 1 ′ of the wheel suspension device that suspends the front wheel. The required damping force is generated by the frictional resistance between the guide bushes 4 ′, 5 ′ and the inner tube 3 ′ which are in sliding contact with each other, and this damping force and the damping force generated in the damping force generation mechanism in the upright front fork 1. As a result, the shock received by the front wheels from the road surface is absorbed and relaxed, thereby improving the riding comfort of the motorcycle.

  As described above, the wheel suspension apparatus according to the present embodiment includes the upright front fork 1 shown in FIG. 1 and the upright oil sliding front fork 1 ′ shown in FIG. Therefore, the structure of the wheel suspension device can be simplified and the cost can be reduced. In the present embodiment, the inner tube 3 ′ is not formed with a horizontal hole. However, if the horizontal hole is provided, the compression ratio of the air chamber Sa is lowered, and the influence of the response of the air spring is reduced. Sexuality is enhanced.

<Embodiment 2>
Next, a second embodiment of the wheel suspension apparatus according to the present invention will be described based on FIG.

  FIG. 6 is a half-cut sectional view of an upright type grease sliding front fork. In this figure, the same elements as those shown in FIG. 5 are denoted by the same reference numerals, and description thereof will be repeated below. Is omitted.

  The upright type grease sliding front fork 1 ″ according to the present embodiment uses oil as working fluid in the upright oil sliding front fork 1 ′ shown in FIG. 5 inside the outer tube 2 ′ and the inner tube 3 ′. Therefore, the basic structure of the upright grease sliding front fork 1 ″ according to the present embodiment is the upright oil according to the first embodiment. Although it is the same as that of the sliding front fork 1 ′, the oil seal 6 ′ (see FIG. 5) is not provided. The dust seal 7 ′ provided on the upright type grease sliding front fork 1 ″ according to the present embodiment functions to prevent dust intrusion and grease leakage.

  Thus, when the front wheel moves up and down following the road surface irregularities during traveling of the motorcycle, in one of the upright type grease sliding front forks 1 ″ of the wheel suspension system that suspends the front wheel, grease that is a lubricant is used. The required damping force is generated by the frictional resistance between the guide bushes 4 ′, 5 ′ and the inner tube 3 ′ which are in sliding contact with each other via the shaft, and this damping force is generated in the damping force generation mechanism in the upright front fork 1. The impact received by the front wheels from the road surface is absorbed and relaxed by the damping force, thereby improving the riding comfort of the motorcycle.

  As described above, the wheel suspension device according to the present embodiment includes the upright front fork 1 shown in FIG. 1 and the upright grease sliding front fork 1 ′ shown in FIG. Therefore, it is possible to obtain the same effect as that of the first embodiment in which the structure of the wheel suspension device can be simplified and the cost can be reduced.

  Although the present invention has been described with respect to an embodiment in which the present invention is applied to an upright front fork for suspending a front wheel of a motorcycle and a wheel suspension device having the front fork, the present invention is not limited to a motorcycle. Needless to say, the present invention can be similarly applied to an upright front fork that suspends the wheels and a wheel suspension device including the upright front fork.

DESCRIPTION OF SYMBOLS 1 Upright type front fork 1 'Upright type oil sliding front fork 1 "Upright type grease sliding front fork 2 Outer tube 3 Inner tube 4,5 Guide bush 6 Oil seal 7 Dust seal 8 Pipe guide 9 Cap 10 Seat pipe 10A Seat pipe piston 11 Bolt 12 Piston ring 13 Oil lock piece 14 Suspension spring 15 Oil lock collar 16, 17 Check valve 18 Rebound spring 19, 20 Oil hole 21 Horizontal hole 22 Distance collar S1 to S3 Oil chamber Sa Air chamber Sδ Ring Gap

Claims (4)

A part of the inner tube on the vehicle body side is inserted into the outer tube on the axle side from above, and the inner tube is supported by the guide bushes fitted on the upper and lower sides of the inner periphery of the outer tube so as to be slidable up and down. A suspension spring is interposed between the outer tube and the inner tube,
Oil is enclosed in the outer tube and the inner tube to form an air chamber in the upper portion of the inner tube, and a damping force is generated by the flow resistance of the oil accompanying expansion and contraction of the outer tube and the inner tube. In an upright front fork equipped with a damping force generation mechanism that
An upright type characterized in that a lateral hole is formed in a side wall of the inner tube to communicate the annular gap defined by the outer tube, the inner tube, and the upper and lower guide bushes with the inside of the inner tube. Front fork. The inner tube is supported by the guide bushes fitted vertically in the outer tube so that the inner tube can slide up and down, and a part of the damping force generation mechanism is provided on the inner periphery of the lower end of the inner tube,
The upright front fork according to claim 1, wherein a lateral hole of the inner tube is formed at a position above the lower guide bushing on the inner periphery of the outer tube.   The upright front fork according to claim 1 or 2, wherein a distance collar is interposed between the upper and lower guide bushes in the annular gap. A device for suspending a wheel between the upright front fork according to any one of claims 1 to 3 and another upright front fork paired therewith,
4. The wheel suspension device according to claim 1, wherein the other upright front fork is configured not to include the suspension spring and the damping force generation mechanism of the upright front fork according to any one of claims 1 to 3. .

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