JP2005313712A - Steering device for saddle type vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To surely relax an impact force by smoothly sliding an inner tube and an outer tube of a front fork with each other to the axial direction when the impact force is applied to the front fork from a traveling surface in the traveling of a saddle type vehicle. <P>SOLUTION: The front fork 10 is provided with the inner tube 23 and the outer tube 24 arranged on an axis 22 extending from a vehicle frame 3 side to a front lower part and having one end sides 25 and 26 silidably fitted with each other along the axial direction, and a seal body 33 sealing the outer peripheral surface of an intermediate part 31 of the inner tube 23 along the axial direction and the end inner peripheral surface 32 of the outer tube 24 on the one end 26 side. The seal body 33 is provided with a metal sliding bush 34 fitted on the inner tube 23 slidably along the axial direction, and a supporting body 35 for elastically supporting the sliding bush 34 to the end inner peripheral surface 32 of the outer tube 24. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a straddle-type vehicle in which a front fork supported by a vehicle body frame includes an inner tube and an outer tube that are slidably fitted to each other in an axial direction, and a seal body that seals between both the tubes. This relates to a steering apparatus.

  2. Description of the Related Art Conventionally, there is a steering device for a saddle-ride type vehicle as shown in FIGS. According to this publication, the steering device includes a front fork that extends from the front end side of the vehicle body frame and supports the front wheels on the extended end portion and is supported by the vehicle body frame so as to be steerable. Is provided. The front fork extends from the vehicle body frame side toward the front lower side, whereby a predetermined caster angle is given to the front fork.

  The front fork includes an inner tube and an outer tube that are arranged on an axis extending from the vehicle body frame side toward the front lower side, and in which the respective end portions are slidably fitted to each other in the axial direction, and the inner tube And a sealing body that seals between the outer peripheral surface of the midway portion in the axial direction and the inner peripheral surface of the end portion on the one end portion side of the outer tube.

  When the vehicle is traveling, when an impact force is applied from the traveling surface to the front fork via the front wheel, the inner tube and the outer tube of the front fork move forward and backward in the axial direction. Then, the oil sealed in these tubes flows in conjunction with the forward and backward sliding, and flows through the nozzles, whereby the impact force is alleviated.

JP-A-9-71283

  By the way, as described above, the front fork extends toward the front lower side from the body frame side. For this reason, the impact force applied by the front fork from the traveling surface during traveling acts as a bending load that curves the front fork downward. At this time, a part of the upper portion of the seal body tends to come into pressure contact with the upper surface of the middle portion in the axial direction of the inner tube in a small area, and the surface pressure increases.

  As a result, when the inner tube and the outer tube slide with each other in the axial direction in an attempt to alleviate the impact force during traveling, the friction between the inner tube and the seal body is increased due to the large surface pressure. Strength increases. For this reason, the mutual smooth sliding of the said inner tube and an outer tube is inhibited, and there exists a possibility that relaxation of the said impact force may be inhibited.

  The present invention has been made paying attention to the above situation, and the object of the present invention is when the front fork is subjected to an impact force from the traveling surface during traveling of the saddle riding type vehicle. An inner tube and an outer tube included in the fork are smoothly slid in the axial direction so that the impact force is more reliably mitigated.

According to the first aspect of the present invention, a front fork 10 is provided that extends from the vehicle body frame 3 toward the front lower side, supports the front wheel 9 at the extended end portion thereof, and is supported by the vehicle body frame 3 so as to be steerable. The front forks 10 are arranged on an axis 22 extending from the vehicle body frame 3 toward the front and lower side, and the one end portions 25 and 26 are fitted to each other so that the ends 25 and 26 are slidable in the axial direction. And an outer tube 24, and a seal body 33 that seals between the outer peripheral surface of the midway portion 31 in the axial direction of the inner tube 23 and the inner peripheral surface 32 of the outer tube 24 on the one end portion 26 side. In a steering device for a riding vehicle,
A metal sliding bush 34 that is externally fitted so that the seal body 33 can slide in the axial direction with respect to the inner tube 23, and an inner peripheral surface 32 of the end portion of the outer tube 24. And a support 35 that is elastically supported.

In addition to the invention of claim 1, the invention of claim 2 is such that the inner diameter D1 of the inner peripheral surface 32 of the end portion of the outer tube 24 is greater than the inner diameter D2 of the portion 41 of the outer tube 24 adjacent to the inner peripheral surface 32 of the end portion. And make it bigger
The sliding bush 34 is separated in the axial direction from the step surface 43 on the inner peripheral surface of the outer tube 24 extending from the inner peripheral surface 32 of the end portion of the outer tube 24 to the portion 41.

  In this section, the reference numerals appended to the above terms are not to be construed as limiting the technical scope of the present invention to the section “Example” described later or the contents of the drawings.

  The effects of the present invention are as follows.

According to the first aspect of the present invention, there is provided a front fork that extends from the vehicle body frame side toward the front lower side, supports a front wheel at its extended end, and is supported by the vehicle body frame so as to be steerable. An inner tube and an outer tube that are arranged on an axial center extending from the vehicle body frame side toward the front lower side and in which the respective end portions are slidably fitted to each other in the axial direction, and the axial direction of the inner tube A straddle-type vehicle steering apparatus including a seal body that seals between an outer peripheral surface of a midway portion and an end inner peripheral surface on one end portion side of the outer tube,
A metal sliding bush that is externally fitted so that the seal body can slide in the axial direction relative to the inner tube, and the sliding bush is elastically supported on the inner peripheral surface of the end portion of the outer tube. And a support.

  Here, as described above, the front fork extends forward and downward from the vehicle body frame side, that is, the front fork is given a caster angle. For this reason, when the vehicle travels, the impact force applied to the front fork from the traveling surface via the front wheels acts as a bending load that curves the front fork downward. At this time, the upper inner peripheral surface of the sliding bush tends to come into pressure contact with the upper surface of the middle portion in the axial direction of the inner tube.

  In this case, as described above, the sliding bush is elastically supported by the support on the inner peripheral surface of the end portion of the outer tube. For this reason, when a part of the upper inner peripheral surface of the sliding bush is pressed against the upper surface of the middle portion of the inner tube, the support is elastically deformed by the pressing force at this time. And by this elastic deformation, the upper inner peripheral surface of the sliding bush comes into surface contact with a wider area with respect to the upper surface of the middle portion of the inner tube. Therefore, the surface pressure of the upper inner peripheral surface of the sliding bush with respect to the upper surface of the middle portion of the inner tube is suppressed to be small.

  As a result, when the inner tube and the outer tube slide relative to each other in the axial direction in an attempt to alleviate the impact force during travel, as described above, the sliding bush is against the upper surface of the middle portion of the inner tube. Since the surface pressure at the time of press contact is small, the frictional force between the inner tube and the sliding bush is suppressed to be small. For this reason, the inner tube and the outer tube slide smoothly with each other, and the impact force is more reliably alleviated.

  In the invention of claim 2, the inner diameter of the inner peripheral surface of the end portion of the outer tube is made larger than the inner diameter of the portion of the outer tube adjacent to the inner peripheral surface of the end portion.

  For this reason, the said support body can be accommodated in the space which arises between the outer peripheral surface of the middle part of the said inner tube, and the edge part inner peripheral surface of the said outer tube. Therefore, even if the support is provided, the gap between the outer peripheral surface of the middle portion of the inner tube and the portion other than the inner peripheral surface of the end portion of the outer tube can be made sufficiently small, and the inner tube It is possible to prevent rattling from occurring between the outer tube.

  Further, the sliding bush is spaced apart in the axial direction from a step surface on the inner peripheral surface of the outer tube extending from the inner peripheral surface of the end portion of the outer tube to the portion.

  Here, as described above, when the upper inner peripheral surface of the sliding bush is in surface contact with the upper surface of the middle portion of the inner tube due to elastic deformation of the support body, the elastic deformation of the support body is accompanied. Thus, the sliding bush moves relative to the step surface. For this reason, the relative movement may cause the sliding bush to be friction bonded to the stepped surface. However, as described above, the sliding bush and the step surface are separated from each other. For this reason, the frictional joining of the sliding bush to the stepped surface is prevented.

  Therefore, the elastic deformation of the elastic body of the support is more smoothly performed because the sliding bush is not frictionally joined to the stepped surface. Then. The upper inner peripheral surface of the sliding bush is more smoothly in surface contact with the upper surface of the middle portion of the inner tube, and the surface pressure is more reliably reduced.

  As a result, the frictional force between the inner tube and the sliding bush is suppressed to be small. For this reason, the inner tube and the outer tube slide smoothly with each other, and the impact force is more reliably mitigated.

  The steering device for a saddle-ride type vehicle according to the present invention relates to an inner tube and an outer tube provided in the front fork in the axial direction when an impact force is applied to the front fork from the running surface when the saddle-type vehicle is running The best mode for carrying out the present invention is as follows in order to realize the purpose of more reliably mitigating the impact force by sliding smoothly on each other.

  That is, a front fork that extends from the vehicle body frame toward the front lower side and supports the front wheel at the extended end portion thereof and is supported to be steerable by the vehicle body frame is provided. The front fork includes an inner tube and an outer tube that are arranged on an axis extending from the vehicle body frame side toward the front lower side, and in which the respective end portions are slidably fitted in the axial direction, and the inner tube. A sealing body that seals between the outer peripheral surface of the midway portion in the axial direction and the inner peripheral surface of the end portion on the one end portion side of the outer tube.

  The seal body includes a metal sliding bush that is externally fitted so as to be slidable in the axial direction with respect to the inner tube, and a support that elastically supports the sliding bush on the inner peripheral surface of the end portion of the outer tube. With body.

  In order to explain the present invention in more detail, an embodiment thereof will be described with reference to the accompanying drawings.

  1 and 2, reference numeral 1 denotes a straddle-type vehicle, more specifically a motorcycle. An arrow Fr in the figure indicates the front of the vehicle 1.

  The vehicle body 2 of the vehicle 1 includes a vehicle body frame 3. The vehicle body frame 3 includes a head pipe 4 that constitutes a front upper end portion thereof, and a main frame 5 that extends rearward and downward from the head pipe 4.

  The vehicle 1 includes a steering device that is supported by the front upper end of the body frame 3. Hereinafter, this steering device will be described. A front fork 10 is provided which extends from the head pipe 4 side toward the front lower side and supports the front wheel 9 by the axle 8 at the extended end portion thereof so as to be steerable by the head pipe 4. . As described above, by extending the front fork 10 from the head pipe 4 side toward the front lower side, a predetermined caster angle is given to the front fork 10. A handle 11 is attached to the upper end of the front fork 10. A rear wheel is supported on the rear portion of the body frame 3 via a rear arm (not shown), and the straddle-type vehicle 1 is supported on the traveling surface 12 by the front wheel 9 and the rear wheel.

  The front fork 10 has a steering shaft 16 supported by the head pipe 4 so as to be rotatable around a steering shaft 15 that is an axis of the head pipe 4, and an upper end portion of the steering shaft 16. The upper bracket 17 is supported by the upper bracket 17 to support the handle 11, the lower bracket 18 is supported by the lower end portion of the steering shaft 16, and the pair of left and right fork pipes 19 supported by the upper bracket 17 and the lower bracket 18. , 19.

  Each of the fork pipes 19 has a hydraulic cylinder structure and has a buffer function. Each fork pipe 19 is disposed on a pair of left and right shaft centers 22, 22 extending from the head pipe 4 side toward the front lower side so as to be parallel to the steering shaft center 15. Each of the fork pipes 19 includes an inner tube 23 and an outer tube 24 arranged on the shafts 22. The inner tube 23 and the outer tube 24 are fitted in such a manner that the ends 25 and 26 facing each other are slidable in the axial direction. In this case, a slight gap is provided between the outer peripheral surface on the one end portion 25 side of the inner tube 23 and the outer peripheral surface on the one end portion 26 side of the outer tube 24.

  The other end portion 28 of each outer tube 24 is fixed to the upper bracket 17 and the lower bracket 18, and the front wheel 9 is supported by the axle 8 on the other end portion 29 of each inner tube 23. That is, the front fork 10 is a so-called inverted type. In addition, a spring (not shown) that separates the inner tube 23 and the outer tube 24 from each other is provided so that each of the fork pipes 19 has a predetermined maximum length. In addition, oil is sealed in the tubes 23 and 24.

  A seal body 33 that seals between the outer peripheral surface of the midway portion 31 in the axial direction of the inner tube 23 and the end inner peripheral surface 32 on the one end portion 26 side of the outer tube 24 is provided. The seal body 33 includes a sliding bush 34 that is externally fitted so as to be slidable in the axial direction relative to the outer peripheral surface of the middle portion 31 of the inner tube 23, and the sliding bush 34 is connected to the outer tube. 24, and a support body 35 that elastically supports the inner peripheral surface 32 of the end portion.

  The support 35 is fitted between the circular inner pipe 37 and the outer pipe 38 which are fitted to each other on the shaft 22 and between the pipes 37 and 38, and is vulcanized and bonded to the pipes 37 and 38b. And a rubber elastic body 39 having a circular pipe shape. The outer pipe 38 is press-fitted and fixed to the inner peripheral surface 32 of the end portion of the outer tube 24, and the inner pipe 37 is fitted into the sliding bush 34 and fixed to each other.

  The inner diameter D1 of the end inner peripheral surface 32 of the outer tube 24 is made larger than the inner diameter D2 of the portion 41 of the outer tube 24 adjacent to the end inner peripheral surface 32. The support 35 is entirely accommodated in an annular space sandwiched between the outer peripheral surface of the middle portion 31 of the inner tube 23 and the inner peripheral surface 32 of the end portion of the outer tube 24. A stepped surface 43 is formed on the inner peripheral surface of the outer tube 24 extending from the inner peripheral surface 32 of the end portion of the outer tube 24 to the portion 41, and the stepped surface 43 extends in a direction orthogonal to the axis 22. . The sliding bush 34 and the inner pipe 37 are spaced apart from the stepped surface 43 by a predetermined dimension A in the axial direction.

  When the vehicle 1 is traveling, when an impact force is applied from the traveling surface 12 to the front fork 10 via the front wheel 9, the inner tube 23 and the outer tube 24 of the front fork 10 move forward and backward in the axial direction. Slide. The oil enclosed in the tubes 23 and 24 in conjunction with the forward and backward sliding flows through the nozzles, whereby the impact force is alleviated.

  According to the above configuration, the metal sliding bush 34 that is externally fitted so that the seal body 33 can slide in the axial direction with respect to the inner tube 23, and the sliding bush 34 is connected to the outer tube 24. And a support 35 that elastically supports the end inner peripheral surface 32.

  2 and 3, particularly, as described above, the front fork 10 extends from the vehicle body frame 3 toward the front lower side, that is, the front fork 10 is given a caster angle. For this reason, when the vehicle 1 travels, the impact force applied by the front fork 10 from the traveling surface 12 via the front wheel 9 acts as a bending load that curves the front fork 10 downward. At this time, the upper inner peripheral surface of the sliding bush 34 tends to press against the upper surface of the midway portion 31 in the axial direction of the inner tube 23.

  In this case, as described above, the sliding bush 34 is elastically supported by the support body 35 on the inner peripheral surface 32 of the end portion of the outer tube 24. For this reason, when a part of the upper inner peripheral surface of the sliding bush 34 tries to come into pressure contact with the upper surface of the middle part 31 of the inner tube 23, the elastic body 39 of the support 35 is caused by the pressure contact force at this time. Elastically deforms. Due to this elastic deformation, the upper inner peripheral surface of the sliding bush 34 comes into surface contact with the upper surface of the middle portion 31 of the inner tube 23 in a wider area. Therefore, the surface pressure of the upper inner peripheral surface of the sliding bush 34 with respect to the upper surface of the middle portion 31 of the inner tube 23 is suppressed to be small.

  As a result, when the inner tube 23 and the outer tube 24 slide in the axial direction in an attempt to alleviate the impact force during traveling, as described above, the upper surface of the middle portion 31 of the inner tube 23 is Since the surface pressure when the sliding bush 34 is in pressure contact is small, the frictional force between the inner tube 23 and the sliding bush 34 is suppressed to be small. For this reason, the inner tube 23 and the outer tube 24 slide smoothly with each other, and the impact force is more reliably alleviated.

  Further, as described above, the inner diameter D1 of the end inner peripheral surface 32 of the outer tube 24 is made larger than the inner diameter D2 of the portion 41 of the outer tube 24 adjacent to the end inner peripheral surface 32.

  For this reason, the said support body 35 can be accommodated in the space produced between the outer peripheral surface of the middle part 31 of the said inner tube 23, and the edge part inner peripheral surface 32 of the said outer tube 24. FIG. Therefore, even if the support 35 is provided, the gap between the outer peripheral surface of the intermediate portion 31 of the inner tube 23 and the portion other than the end inner peripheral surface 32 of the outer tube 24 can be made sufficiently small. Further, rattling between the inner tube 23 and the outer tube 24 can be prevented.

  Further, the sliding bush 34 is separated in the axial direction from the step surface 43 on the inner peripheral surface of the outer tube 24 extending from the end inner peripheral surface 32 of the outer tube 24 to the portion 41.

  Here, as described above, when the upper inner peripheral surface of the sliding bush 34 is about to come into surface contact with the upper surface of the middle portion 31 of the inner tube 23 due to elastic deformation of the elastic body 39 of the support 35, As the support 35 is elastically deformed, the sliding bush 34 moves relative to the stepped surface 43. For this reason, the relative movement may cause the sliding bush 34 to be frictionally joined to the stepped surface 43. However, as described above, the sliding bush 34 and the step surface 43 are separated from each other. For this reason, the frictional joining of the sliding bush 34 to the stepped surface 43 is prevented.

  Therefore, the elastic deformation of the elastic body 39 of the support 35 is more smoothly performed as much as the sliding bush 34 is not frictionally joined to the stepped surface 43. Then. The upper inner circumferential surface of the sliding bush 34 more smoothly contacts the upper surface of the middle portion 31 of the inner tube 23, and the surface pressure is more reliably reduced.

As a result, the frictional force between the inner tube 23 and the sliding bush 34 is suppressed to be small. For this reason, the inner tube 23 and the outer tube 24 slide smoothly with each other, and the impact force is further alleviated more reliably.

  Here, between the inner tube 23 and the sliding bush 34 in the front fork 10 in a state in which the front fork 10 is bent in a convex shape downward and the bending load is applied. The experimental results are described below with respect to the relationship with the generated friction force. The unit of each numerical value is N (Newton).

  According to the above experimental results, it can be seen that in the front fork 10 of the embodiment, the frictional force generated between the inner tube 23 and the sliding bush 34 is significantly reduced.

  Although the above is based on the illustrated example, the saddle riding type vehicle 1 may be an automatic tricycle or an automatic four-wheel vehicle.

  Further, the other end 29 of each inner tube 23 may be fixed to the upper bracket 17 and the lower bracket 18, and the front wheel 9 may be supported by the axle 8 on the other end 28 of each outer tube 24. That is, the front fork 10 may be a so-called upright type.

FIG. 3 is a cross-sectional view taken along line 1-1 in FIG. 2. It is a front part side view of a saddle-ride type vehicle. FIG. 3 is an operation explanatory view in a partially enlarged sectional view of FIG. 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Saddle type vehicle 2 Car body 3 Body frame 4 Head pipe 5 Main frame 9 Front wheel 10 Front fork 12 Running surface 19 Fork pipe 22 Axis 23 Inner tube 24 Outer tube 25 One end part 26 One end part 31 Midway part 32 End inner circumference Surface 33 Seal body 34 Sliding bush 35 Support body 37 Inner pipe 38 Outer pipe 39 Elastic body 41 Part 43 Step surface A Predetermined dimension D1 Inner diameter D2 Inner diameter

Claims (2)

A front fork that extends from the body frame side toward the front lower side and supports the front wheel at the extension end and is supported to be steerable by the body frame is provided. An inner tube and an outer tube that are arranged on an axial center extending toward the front and lower side and in which the respective end portions are slidably fitted to each other in the axial direction; and an outer peripheral surface of a midway portion in the axial direction of the inner tube; In a straddle-type vehicle steering apparatus, comprising: a seal body that seals between an end inner peripheral surface on one end side of the outer tube;
A metal sliding bush that is externally fitted so that the seal body can slide in the axial direction with respect to the inner tube, and the sliding bush is elastically supported on the inner peripheral surface of the end portion of the outer tube. A straddle-type vehicle steering apparatus comprising a support. The inner diameter of the outer peripheral surface of the end portion of the outer tube is larger than the inner diameter of the portion of the outer tube adjacent to the inner peripheral surface of the end portion,
2. The saddle riding according to claim 1, wherein the sliding bush is separated in the axial direction from a step surface on an inner peripheral surface of the outer tube extending from an inner peripheral surface of an end portion of the outer tube to the portion. Type vehicle steering device.

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