JP2007032697A - Front fork of saddle riding vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a front fork in which damping force is more surely produced, and impact force is more surely relieved when an impact force is applied on the front fork from the traveling surface while the vehicle is traveling. <P>SOLUTION: The front fork 4 is provided with a piston rod 21 extending from a piston 20 fitted in a damper tube 16 upward to the upper end of the damper tube 16, and a seal body 22 disposed between the inner peripheral surface of upper end in the damper tube 16 and the outer peripheral surface of the piston rod 21. The seal body 22 is provided with a seal body base 46 attached to the inner peripheral surface of the upper end of the damper tube 16, and first and second lips 47 and 48 projecting from the seal body base 46 upward and downward, and jointed to the outer peripheral surface of the piston rod 21 by each projection. The first and second lips 47 and 48 are made almost into a symmetrical shape about a virtual plane 51 perpendicular to an axis 10 and passing through the seal body base 46. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a front fork of a straddle-type vehicle provided with a seal body that seals between a damper tube and a piston rod that can be slid relative to each other by applying an impact force.

  Conventionally, there is a front fork of the saddle-ride type vehicle described in Patent Document 1 below. 1 and 4 of this publication, the front fork includes a damper tube whose axial center is vertically oriented, and the inside of which is a pressure oil chamber, and the inside of the damper tube is moved upward and downwardly. A piston that is fitted into the damper tube so as to partition into a chamber and that has an orifice that communicates the upper and lower pressure oil chambers with each other; a piston rod that extends from the piston to above the upper end of the damper tube; A seal body that is interposed between the inner peripheral surface of the upper end portion of the damper tube and the outer peripheral surface of the piston rod, and that forms an oil storage chamber adjacent to the upper side of the upper end portion of the damper tube. And a spring that urges the damper tube and the piston rod to move away from each other. The extending end of the piston rod is supported on the vehicle body frame side of the vehicle, and the axle of the front wheel is supported on the lower end of the damper tube.

  When an impact force is applied to the damper tube from the traveling surface through the front wheel and the axle during traveling of the vehicle, the damper tube moves relative to the piston and the piston rod in the axial direction against the spring. The front fork contracts. Then, the hydraulic oil in the lower pressure oil chamber of the damper tube is pressurized by the piston, and the hydraulic oil in the lower pressure oil chamber flows through the orifice to the upper pressure oil chamber. Then, a damping force is generated by this flow, and the impact force is alleviated.

  After the front fork is contracted as described above, the front fork is extended by the elastic energy of the spring that has contracted. Thereafter, the above operations are repeated, the impact force is alleviated, and smooth steering of the vehicle is ensured.

  Here, as described above, when the front fork repeats the contracting operation and the extending operation, the seal body that moves relative to the piston rod together with the damper tube repeats forward and backward sliding with respect to the piston rod. At this time, a gap between the piston rod and the seal body is sealed by the seal body, and leakage of the hydraulic oil in the upper pressure oil chamber is prevented. At this time, the hydraulic oil in the upper pressure oil chamber and the oil storage chamber lubricates the sliding contact portion between the piston rod and the seal body, thereby preventing the seal body from being damaged.

Japanese Patent Laid-Open No. 11-201214

  By the way, as described above, when the front fork contracts by receiving an impact force and the seal body moves relative to the piston rod together with the damper tube in the axial direction, the upper pressure oil chamber expands. Negative pressure. For this reason, the hydraulic oil in the oil storage chamber may be sucked into the upper pressure oil chamber through the gap between the piston rod and the seal body.

  When a large amount of hydraulic oil in the oil storage chamber is sucked into the upper pressure oil chamber, the amount of hydraulic oil flowing through the orifice from the lower pressure oil chamber toward the upper pressure oil chamber is reduced accordingly. This inhibits the generation of damping force, that is, the impact force is inhibited from being relaxed.

  The present invention has been made paying attention to the above-described circumstances, and an object of the present invention is to provide a more reliable damping force when the front fork is given an impact force from the traveling surface when the vehicle is traveling. And the impact force is more reliably mitigated.

The invention of claim 1 includes a damper tube 16 having a longitudinal axis 10 and a piston 20 fitted into the damper tube 16 so as to partition the interior of the damper tube 16 into upper and lower pressure oil chambers 18 and 19; A piston rod 21 extending from the piston 20 to above the upper end portion of the damper tube 16, and a seal body 22 interposed between the inner peripheral surface of the upper end portion of the damper tube 16 and the outer peripheral surface of the piston rod 21. And a casing 24 that forms an oil storage chamber 23 so as to be adjacent to the upper side of the upper end of the damper tube 16, and the damper tube 16 moves relative to the piston 20 and the piston rod 21 in the axial direction. In the front fork of a saddle-ride type vehicle in which damping force is generated,
The seal body 22 protrudes upward and downward from the seal body base 46 attached to the inner peripheral surface of the upper end portion of the damper tube 16, and each of the protrusions of the piston rod 21. First and second lips 47 and 48 joined to the outer peripheral surface,
The first and second lips 47 and 48 are substantially symmetrical with respect to an imaginary plane 51 that is orthogonal to the axis 10 and passes through the seal body base 46.

  According to a second aspect of the present invention, in addition to the first aspect of the invention, the seal body base portion 46 and the first and second lips 47 and 48 are integrally formed.

  According to a third aspect of the present invention, in addition to the first or second aspect of the invention, the damper tube 16 includes a damper tube main body 38 in which the upper and lower pressure oil chambers 18 and 19 are mainly formed, and the damper tube main body 38. And a cylindrical body 39 that is detachably attached to the upper end of the cylindrical body 39. The sealing body 22 is attached to the cylindrical body 39 to form a combined body 44, and the combined body 44 is integrated with the upper end of the damper tube main body 38. It can be attached to and detached from the part.

  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.

  The invention of claim 1 includes, as preconditions, a damper tube whose longitudinal axis is oriented vertically, a piston fitted into the damper tube so as to partition the inside of the damper tube into a lower pressure oil chamber, and A piston rod extending to above the upper end of the damper tube; a seal body interposed between the inner peripheral surface of the upper end of the damper tube and the outer peripheral surface of the piston rod; and an upper end of the damper tube And a casing that forms an oil storage chamber adjacent to the upper side, and the damper tube moves relative to the piston and the piston rod in the axial direction so that a damping force is generated.

  For this reason, when an impact force is applied and the front fork repeats a contracting operation and an extending operation, the seal body moves forward relative to the piston rod and repeats backward sliding. At this time, a gap between the piston rod and the seal body is sealed by the seal body, and leakage of the hydraulic oil in the upper pressure oil chamber is prevented. At this time, the hydraulic oil in the upper pressure oil chamber and the oil storage chamber lubricates the sliding contact portion between the piston rod and the seal body, thereby preventing the seal body from being damaged.

  And in the said structure, a seal body protrudes toward the up-and-down direction from the seal body base part attached to the inner peripheral surface of the upper end part of the said damper tube, and each of these protrusion parts of the said piston rod. First and second lips joined to the outer peripheral surface are provided.

  For this reason, when the front fork is contracted by applying an impact force and the seal body moves relative to the piston rod together with the damper tube in the axial direction, the upper pressure oil chamber expands to generate a negative pressure. become. For this reason, there is a risk that a large amount of hydraulic oil in the oil storage chamber is sucked into the upper pressure oil chamber through the gap between the piston rod and the seal body.

  However, when the front fork contracts as described above, the protruding end surface of the first lip protruding upward scrapes off the hydraulic oil in the oil storage chamber attached to the outer peripheral surface of the piston rod. For this reason, the working oil is prevented from being sucked into the upper pressure oil chamber from the oil storage chamber.

  Therefore, it is possible to prevent the flow rate of the working oil flowing from the lower pressure oil chamber toward the upper pressure oil chamber from being reduced due to a large amount of working oil sucked from the oil storage chamber into the upper pressure oil chamber. . As a result, a damping force is more reliably generated by the flow of the hydraulic oil, and the impact force is more reliably mitigated.

  On the other hand, when the front fork extends and the seal body moves relative to the piston rod together with the damper tube downward in the axial direction, the pressure of the hydraulic oil in the upper pressure oil chamber is pressurized by the piston. To rise. Then, the hydraulic oil in the upper pressure oil chamber tends to leak into the oil storage chamber.

  However, when the front fork extends as described above, the projecting end surface of the second lip projecting downward scrapes off the hydraulic oil in the upper pressure oil chamber adhering to the outer peripheral surface of the piston rod. . For this reason, the hydraulic oil is prevented from leaking from the upper pressure oil chamber.

  Therefore, it is prevented that the flow rate of the working oil flowing from the upper pressure oil chamber to the lower pressure oil chamber is reduced due to leakage of the working oil from the upper pressure oil chamber to the oil storage chamber. As a result, a damping force is more reliably generated by the flow of the hydraulic oil, and the impact force is more reliably mitigated.

  The first and second lips are substantially symmetrical with respect to an imaginary plane orthogonal to the axis and passing through the seal body base.

  For this reason, compared with making the shapes of the first and second lips different from each other, the sealing body can be easily formed.

  According to a second aspect of the present invention, the seal body base and the first and second lips are integrally formed with each other.

  For this reason, the seal body has a reduced number of parts and is compact, so that the configuration of the front fork can be simplified.

  According to a third aspect of the present invention, the damper tube includes a damper tube main body that mainly forms the upper and lower pressure oil chambers, and a cylindrical body that is detachably attached to an upper end portion of the damper tube main body. The seal body is attached to the shape body to form a combined body, and the combined body can be integrally attached to and detached from the upper end portion of the damper tube main body.

  For this reason, when the seal body is assembled to the damper tube in the assembly operation of the front fork, first, the seal body is attached to the inside of the cylindrical body in a wide work space, and then the seal body and the cylinder are installed. What is necessary is just to attach the combination body by a shape body to the said damper tube main body.

  Here, if an attempt is made to attach the seal body directly into the upper end portion of the damper tube of the front fork, this operation tends to be complicated because only the space above the damper tube can be used. However, according to the above configuration, since the cylindrical body can be made short, the work of attaching the seal body to the inside of the cylindrical body can utilize both axially outer spaces of the cylindrical body. This can be done easily. Therefore, as compared with the case where the seal body is directly attached to the damper tube as described above, the assembly work of the front fork can be performed more easily.

  Further, when performing maintenance and inspection work on the seal body, first, the combination body may be detached from the damper tube main body, and the above work may be performed on the seal body through openings at both ends of the cylindrical body. . Therefore, the above-described operation can be facilitated as much as the opening at both ends of the cylindrical body can be used. That is, maintenance and inspection work for the front fork 4 can be facilitated.

  The front fork of the saddle riding type vehicle according to the present invention, when the front fork is given an impact force from the running surface during the running of the vehicle, the front fork generates a damping force more reliably, and the impact force is more reliably mitigated. In order to achieve the purpose of making it happen, the best mode for carrying out the present invention is as follows.

  That is, the front fork has a damper tube whose axial center is vertically oriented and whose inside is a pressure oil chamber, a piston that is fitted into the damper tube so as to partition the upper pressure oil chamber and the lower pressure oil chamber, A piston rod extending from the piston to above the upper end of the damper tube; a seal body interposed between the inner peripheral surface of the upper end of the damper tube and the outer peripheral surface of the piston rod; and the upper end of the damper tube And a casing forming an oil storage chamber so as to be adjacent to the upper side of the section. A damping force is generated by the relative movement of the damper tube relative to the piston and the piston rod in the axial direction.

  The seal body is attached to the inner peripheral surface of the upper end portion of the damper tube, and protrudes upward and downward from the seal body base portion, and each protrusion portion is joined to the outer peripheral surface of the piston rod. First and second lips. The first and second lips are substantially symmetrical with respect to a virtual plane orthogonal to the axis and passing through the seal body base.

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

  2 and 3, reference numeral 1 denotes a straddle-type vehicle exemplified as a motorcycle. An arrow Fr indicates the front of the vehicle 1 in the traveling direction.

  The vehicle 1 includes a body frame 2, a front fork 4 that is steerably supported by a head pipe 3 of the body frame 2, and a front wheel 6 that is supported on the front fork 4 by an axle 5. . The vehicle 1 is allowed to travel with its front wheels 6 and rear wheels (not shown) grounded on the traveling surface 9.

  The front fork 4 is inserted into the head pipe 3 and supported by a steering shaft (not shown) that is rotatably supported around the axis 10 of the head pipe 3, and is supported on the upper and lower ends of the steering shaft. Upper and lower brackets 11 and 12 and a pair of left and right shock absorbers that extend in a longitudinal direction parallel to the shaft center 10 and are supported across the upper and lower brackets 11 and 12 and that support the axle 5 13.

  In all the drawings, the shock absorber 13 includes a damper tube 16 having a longitudinal axis 14 and containing hydraulic oil 15, and an axle that is supported by a lower end portion of the damper tube 16 and supports the axle 5. A bracket 17 and a piston 20 that is fitted into the damper tube 16 so as to be relatively slidable in the axial direction and partitions the pressure oil chamber in the damper tube 16 into upper and lower pressure oil chambers 18 and 19; A piston rod 21 that extends from the piston 20 to above the upper end of the damper tube 16 and that is supported by the upper and lower brackets 11 and 12 on the vehicle body frame 2 side, and an upper end of the damper tube 16. A sealing body 22 interposed between the inner peripheral surface of the part and the outer peripheral surface of the piston rod 21 to seal this portion, and an upper side of the upper end of the damper tube 16 And a casing 24 forming the adjacent oil sump 23. The oil storage chamber 23 is communicated with the atmosphere and is always maintained at atmospheric pressure.

  Further, the shock absorber 13 is externally fitted to the damper tube 16 and the casing 24, the upper portion is coupled to the upper end portion of the casing 24, and the lower end portion is supported by the outer tube 25 supporting the axle bracket 17, and the outer tube 25. An upper part of the tube 25, an upper part of the damper tube 16, and a piston tube 21, and an upper end of the tube 25 is coupled to the upper end of the piston rod 21; A spring 27 that biases the damper tube 16 and the piston rod 21 apart from each other is provided, and the piston 20 is formed with an orifice 28 that allows the upper and lower pressure oil chambers 18 and 19 to communicate with each other. .

  The shock absorber 13 includes a cylinder tube 30 attached to the axle bracket 17, a free piston 33 that partitions the inside of the cylinder tube 30 into first and second chambers 31 and 32, and the lower pressure oil chamber 19. An adjustment valve 35 is provided which can adjust the opening degree of the oil passage 34 formed to communicate with the first chamber 31. The first chamber 31 and the oil passage 34 are filled with hydraulic oil 15, and the second chamber 32 is filled with gas to form a gas chamber. In the shock absorber 13, the damper tube 16, the piston 20, and the piston rod 21 are moved relative to each other while being opposed to the spring 27 so that the contraction operation A is possible. On the other hand, the shock absorber 13 can be extended by the relative movement of the damper tube 16, the piston 20 and the piston rod 21 by the biasing force of the spring 27.

  The damper tube 16 is detachably attached to the damper tube main body 38 that mainly forms the upper and lower pressure oil chambers 18 and 19 and to the inner peripheral surface of the upper end portion of the damper tube main body 38 by twisting around the axis 14. A cylindrical body 39, a flange 40 integrally formed on the upper end portion of the cylindrical body 39 and joined to the upper end surface of the damper tube main body 38, and an annular shape press-fitted into the lower end portion of the damper tube main body 38. A body 41 and an annular sealing member 42 made of Teflon (registered trademark), which is fitted into the annular body 41 in a press-fit manner and can slide relative to the piston rod 21 in the axial direction, are provided. An O-ring 43 is interposed and sealed between the inner peripheral surface of the upper end portion of the damper tube main body 38 and the outer peripheral surface of the upper end portion of the cylindrical body 39.

  The seal body 22 is attached to the inner peripheral surface of the cylindrical body 39. The seal body 22, the cylindrical body 39, the flange 40, the annular body 41, and the seal material 42 are combined into an integral combination body 44, and this combination body 44 is integrally attached to and detached from the upper end surface of the damper tube main body 38. It is possible.

  The seal body 22 has a seal body base portion 46 attached to the inner peripheral surface of the cylindrical body 39, and projects upward and downward from the seal body base portion 46. Each projection portion projects from the outer peripheral surface of the piston rod 21. The first and second lips 47 and 48 joined in a press-contact manner, and the protrusions of the first and second lips 47 and 48 are bent into an annular shape for further press-contact with the outer peripheral surface of the piston rod 21. And biasing tools 49 and 50 made of coil springs.

  The first and second lips 47 and 48 are symmetrical with respect to an imaginary plane 51 that is orthogonal to the axis 10 and passes through the seal body base 46. ing. The seal body base 46, the first lip 47, and the second lip 48 of the seal body 22 are rubber elastic bodies and are integrally formed with each other.

  The projecting end surfaces of the first and second lips 47, 48 have a truncated conical shape, and the intersection angles θ1, θ2 formed by the projecting end surfaces and the outer peripheral surface of the piston rod 21 are 35-55 °. ing. In this case, more preferably, θ1, θ2 = 40-50 °, and θ1> θ2. Each θ3 formed by the inner peripheral surface of the first and second lips 47, 48 on the piston rod 21 side and the outer peripheral surface of the piston rod 21 is 15-35 °. In addition, the dimension between the joint points of the first and second lips 47 and 48 with respect to the outer peripheral surface of the piston rod 21 is 25-35 mm. .

  When an impact force is applied to the shock absorber 13 from the traveling surface 9 through the front wheel 6 and the axle 5 during the traveling of the vehicle 1, the damper tube 16 is opposed to the spring 27 so that the damper tube 16 and the piston rod 21. As a result, the front fork 4 is contracted A. Then, the hydraulic oil 15 in the lower pressure oil chamber 19 is pressurized by the piston 20, and the hydraulic oil 15 in the lower pressure oil chamber 19 flows through the orifice 28 to the upper pressure oil chamber 18. When the hydraulic oil 15 is caused to flow through the orifice 28, the flow is restricted, a damping force is generated, and the impact force is alleviated.

  After the front fork 4 has contracted A as described above, the front fork 4 is expanded by the elastic energy of the spring 27 that has contracted A as described above.

  Further, during the contraction operation A and extension operation B of the shock absorber 13, the piston rod 21 is inserted and removed from the inside of the damper tube 16, and the volume in the damper tube 16 changes. It is absorbed by the contraction and expansion of the gas in the second chamber 32 accompanying the operation of the free piston 33. The speed of the contraction operation A is about twice that of the extension operation B. Thereafter, the above operations A and B are repeated, the impact force is alleviated, and the smooth steering of the vehicle is ensured.

  In the above case, when an impact force is applied and the front fork 4 repeats the contracting operation A and the extending operation B, the seal body 22 moves forward relative to the piston rod 21 and repeats backward sliding. At this time, a gap between the piston rod 21 and the seal body 22 is sealed by the seal body 22, and leakage of hydraulic oil in the upper pressure oil chamber 18 is prevented. At this time, the hydraulic oil 15 in the upper pressure oil chamber 18 and the oil storage chamber 23 lubricates the sliding contact portion between the piston rod 21 and the seal body 22 to prevent the seal body 22 from being damaged.

  When the front fork 4 is contracted by an impact force A and the seal body 22 moves relative to the piston rod 21 together with the damper tube 16 in the axial direction, the upper pressure oil chamber 18 Expands to negative pressure. For this reason, there is a possibility that a large amount of the hydraulic oil 15 in the oil storage chamber 23 is sucked into the upper pressure oil chamber 18 through the gap between the piston rod 21 and the seal body 22.

  However, when the front fork 4 performs the contracting operation A as described above, the projecting end surface of the first lip 47 projecting upward is attached to the outer peripheral surface of the piston rod 21 and the hydraulic oil in the oil storage chamber 23. Scratch 15 off. For this reason, the hydraulic oil 15 is prevented from being sucked into the upper pressure oil chamber 18 from the oil storage chamber 23.

  Accordingly, when a large amount of hydraulic oil 15 is sucked from the oil storage chamber 23 into the upper pressure oil chamber 18, the flow rate of the hydraulic oil 15 flowing through the orifice 28 from the lower pressure oil chamber 19 toward the upper pressure oil chamber 18 is increased. It is prevented that it decreases. As a result, the damping force is more reliably generated by the flow of the hydraulic oil 15 in the orifice 28, and the impact force is more reliably mitigated.

  On the other hand, when the front fork 4 extends B and the seal body 22 moves relative to the piston rod 21 together with the damper tube 16 in the axial direction, the upper pressure oil chamber is pressurized by the piston 20. The pressure of the 18 hydraulic oil 15 rises. Then, the hydraulic oil 15 in the upper pressure oil chamber 18 tends to leak into the oil storage chamber 23.

  However, when the front fork 4 is extended B as described above, the protruding end surface of the second lip 48 protruding downward is attached to the outer peripheral surface of the piston rod 21 of the upper pressure oil chamber 18. The hydraulic oil 15 is scraped off. For this reason, the hydraulic oil 15 is prevented from leaking from the upper pressure oil chamber 18.

  Therefore, when the hydraulic oil 15 leaks from the upper pressure oil chamber 18 to the oil storage chamber 23, the flow rate of the hydraulic oil 15 flowing through the orifice 28 from the upper pressure oil chamber 18 toward the lower pressure oil chamber 19 decreases. This is prevented. As a result, the damping force is more reliably generated by the flow of the hydraulic oil 15 in the orifice 28, and the impact force is more reliably mitigated.

  In the free state of the front fork 4, the pressure contact force by the biasing tool 49 of the first lip 47 to the piston rod 21 and the pressure contact force by the biasing tool 50 of the second lip 48 to the piston rod 21 Are almost the same as each other.

  Further, as described above, the first and second lips 47 and 48 are substantially symmetrical with respect to the virtual plane 51 that is orthogonal to the axis 10 and passes through the seal body base 46.

  For this reason, it is possible to easily form the seal body 22 as compared to making the shapes of the first and second lips 47 and 48 different from each other.

  Further, as described above, the seal body base 46 and the first and second lips 47 and 48 are formed integrally with each other.

  For this reason, the sealing body 22 has a reduced number of parts and is compact, and thus the configuration of the front fork 4 can be simplified.

  Further, as described above, the damper tube 16 includes the damper tube main body 38 that mainly molds the upper and lower pressure oil chambers 18 and 19, and the cylindrical body 39 that is detachably attached to the upper end portion of the damper tube main body 38. The sealing body 22 is attached to the cylindrical body 39 to form a combined body 44, and the combined body 44 can be integrally attached to and detached from the upper end portion of the damper tube main body 38.

  Therefore, when the seal body 22 is assembled to the damper tube 16 in the assembly work of the front fork 4, first, the seal body 22 is attached to the inside of the cylindrical body 39 in a wide work space, and then A combination body 44 composed of the seal body 22 and the cylindrical body 39 may be attached to the damper tube main body 38.

  Here, if the seal body 22 is directly attached to the upper end portion of the damper tube 16 of the front fork 4, this operation becomes complicated because only the space above the damper tube 16 can be used. Tend to. However, according to the above configuration, since the cylindrical body 39 can be made short, the work of attaching the seal body 22 to the inside of the cylindrical body 39 requires both spaces on the outer sides in the axial direction of the cylindrical body 39. This can be done easily. Therefore, as compared with the case where the seal body 22 is directly attached to the damper tube 16 as described above, the assembly work of the front fork 4 can be facilitated.

  When performing maintenance or inspection work on the seal body 22, first, the combination body 44 is detached from the damper tube main body 38, and both ends of the cylindrical body 39 are passed through the openings on both ends of the seal body 22. You just have to work. Therefore, the above-described operation can be facilitated as much as the opening at both ends of the cylindrical body 39 can be used. That is, maintenance and inspection work for the front fork 4 can be facilitated.

  Although the above is based on the illustrated example, the saddle riding type vehicle may be a motor tricycle.

FIG. 4 is a partially enlarged sectional view of FIG. 3. 1 is a front side view of a motorcycle. FIG. 3 is a partially enlarged sectional view of FIG. 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vehicle 2 Body frame 4 Front fork 5 Axle 6 Front wheel 10 Axle center 13 Shock absorber 14 Axle center 15 Hydraulic oil 16 Damper tube 17 Axle bracket 18 Upper pressure oil chamber 19 Lower pressure oil chamber 20 Piston 21 Piston rod 22 Seal body 23 Oil storage chamber 24 Casing 28 Orifice 38 Damper tube body 39 Cylindrical body 44 Combined body 46 Seal body base 47 First lip 48 Second lip 49 Energizing tool 50 Energizing tool 51 Virtual surface A Contracting operation B Extending operation θ1-θ3 Intersection angle

Claims (3)

A damper tube having a longitudinal axis, a piston fitted into the damper tube so as to partition the inside of the damper tube into a lower pressure oil chamber, and a piston extending from the piston to above the upper end of the damper tube A rod, a seal body interposed between the inner peripheral surface of the upper end portion of the damper tube and the outer peripheral surface of the piston rod, and a casing forming an oil storage chamber adjacent to the upper side of the upper end portion of the damper tube; In a front fork of a saddle-ride type vehicle in which a damping force is generated by the relative movement of the damper tube in the axial direction with respect to the piston and the piston rod,
The seal body is attached to the inner peripheral surface of the upper end portion of the damper tube, and protrudes upward and downward from the seal body base portion, and each of the protrusion portions is joined to the outer peripheral surface of the piston rod. A first lip and a second lip;
A front fork of a straddle-type vehicle, wherein the first and second lips are substantially symmetrical with respect to an imaginary plane that is orthogonal to the axis and passes through a seal body base.   The front fork of a saddle-ride type vehicle according to claim 1, wherein the seal body base and the first and second lips are formed integrally with each other.   The damper tube includes a damper tube main body that mainly forms the upper and lower pressure oil chambers, and a cylindrical body that is detachably attached to an upper end portion of the damper tube main body, and the sealing body is attached to the cylindrical body. 3. The front fork of a saddle-ride type vehicle according to claim 1, wherein the front fork of the straddle-type vehicle according to claim 1 or 2, wherein the front fork of the straddle-type vehicle is attached to form a combined body, and the combined body is integrally detachable from an upper end portion of the damper tube body.

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