JP2014145475A - Front fork - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent gas leakage of an air supply/exhaust valve caused by telescopic strokes of a front fork.SOLUTION: A front fork 10 includes an axle side tube 12 inserted into a vehicle body side tube 11, an air chamber 81 attached to the vehicle body side tube 11 and the axle side tube 12, and an air supply/exhaust valve 94 adjusting the pressure in the air chamber 81. An attachment direction along the axial direction of the air supply/exhaust valve 94 is arranged to cross a direction of an inertia force caused by telescopic strokes of the front fork 10.

Description

  The present invention relates to a front fork for a motorcycle.

  As a front fork for a motorcycle, for example, as described in Patent Document 1, a vehicle body side tube and an axle side tube are inserted into each other, a gas chamber is attached to the vehicle body side tube and the axle side tube, and the pressure of the gas chamber is adjusted. Some are equipped with valves. The free piston is pressed by the pressure of the gas chamber formed in the tank provided outside the axle side tube, and the pressure of the oil chamber pressurized by this is exerted on the compression side cylinder chamber inside the vehicle body side tube and the axle side tube. Thus, it is intended to avoid the generation delay of the damping force in the extension side stroke following the compression side stroke.

  In the front fork for a motorcycle described in Patent Document 1, a supply / exhaust valve for adjusting the pressure of a gas chamber formed in the tank is attached to the tank. In general, as described in, for example, Patent Document 2, a supply / exhaust valve is configured such that a valve main body is assembled in a penetrating manner to a valve core fixed to a tank side, and a valve main body biased by a spring is pressed against a valve seat of the valve core. Thus, when the valve body is pushed from the outside, the valve body moves in the axial direction so that the valve body opens away from the valve seat of the valve core, thereby allowing gas pressure to flow in and out.

JP-B-60-20225 JP2005-59687

  However, in the front fork for a motorcycle described in Patent Document 1, the mounting direction along the axial direction of the air supply / exhaust valve mounted on the tank is the same as the axial direction of the vehicle body side tube and the axle side tube. Is set in the direction along.

  Therefore, when the vehicle body side tube and the axle side tube are pushed up by the convex part of the road surface during the expansion and contraction stroke of the front fork during the traveling of the motorcycle, the supply and exhaust valves together with the tank are moved together in the axial direction of the body side tube and the axle side tube. It is pushed up. At this time, the supply / exhaust valve has the axial direction of the valve core and the valve body along the axial direction of the vehicle body side tube and the axle side tube, while the valve core fixed to the tank side moves with the tank in the axial direction, Only the valve body is left behind in its axial direction by inertia. As a result, the valve main body is separated from the valve seat of the valve core to be in an unexpected valve opening state, causing a gas leak.

  An object of the present invention is to prevent gas leakage of an air supply / exhaust valve caused by an expansion / contraction stroke of a front fork.

  The invention according to claim 1 is a front fork in which a vehicle body side tube and an axle side tube are inserted into each other, a gas chamber is attached to the vehicle body side tube and the axle side tube, and a supply / exhaust valve for adjusting the pressure of the gas chamber is attached. The mounting direction along the axial direction of the air supply / exhaust valve intersects with the direction of the inertial force due to the expansion / contraction stroke of the front fork.

  The invention according to claim 2 is the invention according to claim 1, wherein the gas chamber is an air spring chamber.

  In the invention according to claim 3, in the invention according to claim 1 or 2, the supply / exhaust valve is further closed by pressing a valve body biased by a spring against a valve seat of a valve core. Is.

  The invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein the air supply / exhaust valve is attached to an upper end closing member of the vehicle body side tube.

  The invention according to claim 5 is the invention according to any one of claims 1 to 3, wherein the air supply / exhaust valve is further attached to a lower end closing member of the axle side tube.

  The invention according to claim 6 is the invention according to any one of claims 1 to 3, wherein the air supply / exhaust valve is attached to a sub tank provided outside the vehicle body side tube and the axle side tube. is there.

(Claim 1)
(a) The mounting direction along the axial direction of the air supply / exhaust valve is arranged to intersect the direction of the inertial force due to the expansion / contraction stroke of the front fork. When the vehicle body side tube and axle side tube are pushed up by the convex part of the road surface during the extension stroke of the front fork during traveling of the motorcycle, the mounting direction along the axial direction of the air supply / exhaust valve is the direction of the inertial force due to the extension stroke of the front fork (The direction of expansion and contraction of the front fork) (the direction along the axial direction of the vehicle body side tube and the axle side tube) is not matched. Therefore, even if the air supply / exhaust valve is pushed up together with the tubes in the vehicle body side tube and the axle side tube, the air supply / exhaust valve does not move in the axial direction, and the valve body remains in the axial direction. Therefore, there is no risk of causing gas leakage without unexpected valve opening.

(Claim 2)
(b) The gas chamber is an air spring chamber. Gas leakage of the air supply / exhaust valve that changes the air pressure of the air spring chamber can be prevented, and the stability of the total length of the front fork and the riding height can be ensured.

(Claim 3)
(c) The supply / exhaust valve is closed by pressing a valve body biased by a spring against a valve seat of a valve core. Gas leakage can be prevented while using a simple configuration air supply / exhaust valve.

(Claim 4)
(d) The air supply / exhaust valve is attached to the upper end closing member of the vehicle body side tube. Gas leakage of the air supply / exhaust valve attached to the upper end closing member of the vehicle body side tube can be prevented.

(Claim 5)
(e) The air supply / exhaust valve is attached to the lower end closing member of the axle side tube. Gas leakage of the air supply / exhaust valve attached to the lower end closing member of the axle side tube can be prevented.

(Claim 6)
(f) The supply / exhaust valve is attached to a sub tank provided outside the vehicle body side tube and the axle side tube. Gas leakage of the supply / exhaust valve attached to the sub tank can be prevented.

FIG. 1 is a sectional view showing a front fork. FIG. 2 is a plan view of FIG. FIG. 3 is an enlarged cross-sectional view of the lower part of FIG. 4 is an enlarged cross-sectional view of the middle part of FIG. FIG. 5 is an enlarged cross-sectional view of the upper part of FIG. FIG. 6 is a schematic view showing an air supply / exhaust valve.

  As shown in FIGS. 1 to 5, the front fork 10 slidably inserts an axle side tube (inner tube) 12 into a vehicle body side tube (outer tube) 11. The front fork 10 suspends a guide cylinder 21 at the center inside the vehicle body side tube 11, and a tip guide 23 of a guide rod 22 erected at the center inside the axle side tube 12 is slidably inserted into the guide cylinder 21. doing.

  The vehicle body side tube 11 is supported on the vehicle body side, and the axle side tube 12 is coupled to the axle. The upper opening end of the vehicle body side tube 11 is closed and sealed with a cap 30 and a fork bolt 31. A guide cylinder 21 is connected to and suspended from the lower end of the cap 30.

  An axle bracket 32 is screwed and sealed to the lower end portion of the axle tube 12, and the bottom piece 33 is held between the lower end surface of the axle tube 12 and the bottom surface of the axle bracket 32. And the lower end part of the guide rod 22 is standingly arranged in the center part of the axle bracket 32 inside the axle side tube 12. A lower end portion of the guide rod 22 is screwed to a bottom bolt 34 that is engaged with and sealed in the bottom portion of the axle bracket 32 from the outside, and is fixed by a lock nut 35. The guide rod 22 is slidably supported by a rod guide 36 screwed to the lower opening end of the guide cylinder 21 and is inserted into the guide cylinder 21. A guide 23 is screwed to the tip of a guide rod 22 inserted into the guide cylinder 21.

  In the front fork 10, the inner air spring chamber 50 in which the tip guide 23 of the guide rod 22 is defined inside the guide cylinder 21, and the vehicle body side tube 11 and the axle side tube 12 are outside the inner air spring chamber 50 in the guide cylinder 21. And an outer air spring chamber 60 to be partitioned. Further, the front fork 10 is provided inside the guide cylinder 21 with a rod guide 36 provided in the guide cylinder 21 for inserting and supporting the guide rod 22 and a tip guide 23 of the guide rod 22 inserted into the guide cylinder 21. It has a rebound air spring chamber 70 that is sandwiched and partitioned. Thereby, the front fork 10 constitutes the suspension spring 40 by the air spring of the inner air spring chamber 50, the air spring of the outer air spring chamber 60, and the air spring of the rebound air spring chamber 70.

  The inner air spring chamber 50 is defined inside the guide cylinder 21 on the side where the guide rod 22 does not exist, sandwiched between the fork bolt 31 and the tip guide 23 of the guide rod 22. The air pressure in the inner air spring chamber 50 is adjusted by a supply / exhaust valve 51. As shown in FIGS. 2 and 5, the air supply / exhaust valve 51 is attached to a position facing the outside of the fork bolt 31 and communicates with the inner air spring chamber 50 to adjust the enclosed air pressure of the inner air spring chamber 50.

  The outer air spring chamber 60 is a space defined by the vehicle body side tube 11 and the axle side tube 12 outside the guide cylinder 21. The air pressure in the outer air spring chamber 60 is adjusted by a supply / exhaust valve 61. As shown in FIG. 2, the air supply / exhaust valve 61 is attached to a position facing the outside of the fork bolt 31 and communicates with the outer air spring chamber 60 to adjust the enclosed air pressure of the outer air spring chamber 60.

  The front fork 10 forms an air spring by the inner air spring chamber 50 and the outer air spring chamber 60 which are compressed in the compression side stroke. The spring force F1 of the air spring in the inner air spring chamber 50 and the spring force F2 of the air spring in the outer air spring chamber 60 urge the vehicle body side tube 11 and the axle side tube 12 in the extending direction.

  The front fork 10 can form an oil chamber filled with lubricating oil at the lower part of the outer air spring chamber 60. The sliding portions of the vehicle body side tube 11 and the axle side tube 12 and the sliding portions of the guide cylinder 21 and the guide rod 22 are lubricated.

  As described above, the front fork 10 is provided in the guide cylinder 21 inside the guide cylinder 21 to insert and support the guide rod 22, and the tip guide 23 of the guide rod 22 inserted into the guide cylinder 21. A rebound air spring chamber 70 that is sandwiched between the two. As shown in FIG. 3, the front fork 10 is provided with a sub tank 80 having an air chamber 81 communicating with the rebound air spring chamber 70 outside the vehicle body side tube 11 and the axle side tube 12. In the present embodiment, the sub tank 80 is integrally formed with the axle bracket 32 that is screwed to the lower end portion of the axle side tube 12. The air chamber 81 of the sub tank 80 communicates with the rebound air spring chamber 70 through the communication hole 34A of the bottom bolt 34, the hollow portion 22A of the guide rod 22, and the communication hole 23A of the tip guide 23.

  As shown in FIG. 3, the sub tank 80 has an air chamber 81 in which a vertical chamber 81A and a horizontal chamber 81B (not shown) are coupled in an L shape. A cap 82 is sealed and screwed into the opening facing the upper side of the vertical chamber 81A. An adjuster bolt 91 of the volume adjusting device 90 is screwed into the center portion of the cap 82. An air supply / exhaust valve 94 is sealed and screwed into the center hole of the adjuster bolt 91. A valve cover 95 that covers the supply / exhaust valve 94 is screwed into the central opening of the adjuster bolt 91. The volume adjusting device 90 can adjust the volume of the air chamber 81 by screwing the adjuster bolt 91 to move the piston 92 forward and backward. Further, the supply / exhaust valve 94 is used to adjust the pressure in the air chamber 91 by supplying / exhausting, and the enclosed air pressure in the rebound air spring chamber 70 is adjusted accordingly.

  The front fork 10 forms an air spring by the rebound air spring chamber 70 compressed on the extending side of the extending side stroke. The spring force F3 of the air spring in the rebound air spring chamber 70 is such that the vehicle body side tube 11 and the axle side tube 12 are urged by the spring forces F1, F2 of the air springs in the inner air spring chamber 50 and the outer air spring chamber 60. In the direction in which the vehicle body side tube 11 and the axle side tube 12 are contracted against the spring force F1 of the air spring of the inner air spring chamber 50 and the spring force F2 of the air spring of the outer air spring chamber 60. Energize.

  Therefore, in the front fork 10, the spring force F 1 of the air spring of the inner air spring chamber 50 that urges the vehicle body side tube 11 and the axle side tube 12 to extend with respect to the expansion / contraction stroke of the front fork 10 and the outside The spring force F2 of the air spring of the air spring chamber 60 and the spring force F3 of the air spring of the rebound air spring chamber 70 that urges the vehicle body side tube 11 and the axle side tube 12 in the direction of contraction on the extended side are A combined spring force F that is the sum is generated. The combined spring force F increases the spring force in the latter half of the compression side without increasing the spring force in the initial to intermediate range on the extension side of the expansion / contraction stroke.

  However, in the front fork 10, in order to prevent gas leakage from the supply / exhaust valves 51, 61, 94 for adjusting the respective air pressures of the inner air spring chamber 50, the outer air spring chamber 60, and the rebound air spring chamber 70. The following configuration is provided.

  Here, as shown in FIG. 6, each of the air supply / exhaust valves 51, 61, 94 is screwed into each of the fork bolts 31, 31, which are upper end closing members of the vehicle body side tube 11, and an adjuster bolt 91 provided in the sub tank 80. Embedded in the valve core 102, a cylindrical valve core 102 fixed to the inner periphery of the stem 101, a shaft valve body 103 assembled in a penetrating manner in the axial direction of the inner periphery of the valve core 102, and the valve core 102. The valve body 103 is configured to have a spring (not shown) for pressing the valve body 103 against the valve seat 102A of the valve core 102. The supply / exhaust valves 51, 61, 94 are closed by pressing the valve body 103 biased by a spring against the valve seat 102A of the valve core 102, and when the valve body 103 is pressed from the outside, the valve body 103 Is moved in the axial direction so as to be opened away from the valve seat 102A of the valve core 102, and air pressure can flow in and out.

(Supply / exhaust valves 51, 61)
The supply / exhaust valves 51 and 61 are attached to the fork bolt 31 which is an upper end closing member of the vehicle body side tube 11 as follows. The mounting structure of the air supply / exhaust valves 51 and 61 is the same, and the air supply / exhaust valve 51 will be described as a representative.

  As shown in FIG. 5, the mounting direction along the axial direction of the air supply / exhaust valve 51 (the axial direction of the stem 101, the valve core 102, and the valve main body 103) is the direction of inertia force due to the expansion / contraction stroke of the front fork 10 (extension / contraction of the front fork 10). (Moving direction) (a direction along the axial direction of the vehicle body side tube 11 and the axle side tube 12) is obliquely crossed with each other.

Therefore, according to the present embodiment, the following operational effects can be obtained.
(a) The mounting direction along the axial direction of the air supply / exhaust valve 51 is obliquely crossed with respect to the direction of the inertial force due to the expansion / contraction stroke of the front fork 10. When the vehicle body side tube 11 and the axle side tube 12 are pushed up by the convex portion of the road surface during the extension stroke of the front fork 10 while the motorcycle is running, the attachment direction along the axial direction of the air supply / exhaust valve 51 is the extension stroke of the front fork 10. Does not coincide with the direction of the inertial force (the direction of expansion and contraction of the front fork 10) (the direction along the axial direction of the vehicle body side tube 11 and the axle side tube 12). Therefore, even if the air supply / exhaust valve 51 is pushed up together with the tubes 11 and 12 in the axial direction of the vehicle body side tube 11 and the axle side tube 12, the air supply / exhaust valve 51 does not move in the axial direction. The main body 103 is not left in the axial direction and the valve is not opened unexpectedly, and there is no possibility of causing gas leakage.

  (b) The gas chamber is the inner air spring chamber 50. Gas leakage of the air supply / exhaust valve 51 that changes the air pressure of the inner air spring chamber 50 can be prevented, and the stability of the overall length of the front fork 10 and, in turn, the riding height posture can be ensured.

  (c) The supply / exhaust valve 51 is closed by pressing the valve body 103 biased by a spring against the valve seat 102A of the valve core 102. Gas leakage can be prevented while using the simple configuration air supply / exhaust valve 51.

  (d) The supply / exhaust valve 51 is attached to the fork bolt 31 of the vehicle body side tube 11. Gas leakage of the air supply / exhaust valve 51 attached to the fork bolt 31 of the vehicle body side tube 11 can be prevented.

(Supply / Exhaust Valve 94)
The air supply / exhaust valve 94 is attached to an adjuster bolt 91 provided in the sub tank 80 as follows. As shown in FIG. 3, the mounting direction along the axial direction of the air supply / exhaust valve 94 (the axial direction of the stem 101, the valve core 102, and the valve main body 103) is the direction of inertia force due to the expansion / contraction stroke of the front fork 10 (extension / contraction of the front fork 10). (Moving direction) (direction along the axial direction of the vehicle body side tube 11 and the axle side tube 12) is obliquely crossed (or orthogonal).

Therefore, according to the present embodiment, the following operational effects can be obtained.
(a) The mounting direction along the axial direction of the air supply / exhaust valve 94 is obliquely crossed (or orthogonal) with respect to the direction of the inertial force due to the expansion / contraction stroke of the front fork 10. When the vehicle body side tube 11 and the axle side tube 12 are pushed up by the convex portion of the road surface during the extension stroke of the front fork 10 during traveling of the motorcycle, the attachment direction along the axial direction of the air supply / exhaust valve 94 is the extension stroke of the front fork 10. Does not coincide with the direction of the inertial force (the direction of expansion and contraction of the front fork 10) (the direction along the axial direction of the vehicle body side tube 11 and the axle side tube 12). Therefore, even when the air supply / exhaust valve 94 is pushed up together with the tubes 11 and 12 in the axial direction of the vehicle body side tube 11 and the axle side tube 12, the air supply / exhaust valve 94 does not move in the axial direction. The main body 103 is not left in the axial direction and the valve is not opened unexpectedly, and there is no possibility of causing gas leakage.

  (b) The gas chamber is the rebound air spring chamber 70. Gas leakage of the air supply / exhaust valve 94 for changing the air pressure in the rebound air spring chamber 70 can be prevented, and the stability of the full length of the front fork 10 and the riding height posture can be ensured when riding.

  (c) The supply / exhaust valve 94 is closed by pressing the valve body 103 biased by a spring against the valve seat 102A of the valve core 102. Gas leakage can be prevented while using a simple configuration air supply / exhaust valve 94.

  (d) The supply / exhaust valve 94 is attached to a sub tank 80 provided outside the vehicle body side tube 11 and the axle side tube 12. Gas leakage of the supply / exhaust valve 94 attached to the sub tank 80 can be prevented.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration of the present invention is not limited to this embodiment, and even if there is a design change or the like without departing from the gist of the present invention. It is included in the present invention. For example, the air supply / exhaust valve according to the present invention may be attached to the lower end closing member (the bottom bolt 34 or the like) of the axle side tube in the front fork.

  The supply / exhaust valve of the present invention may be a supply / exhaust valve that adjusts the pressure of the gas chamber for pressurizing the hydraulic oil in the oil chamber of the front fork.

  The present invention provides a front fork in which a vehicle body side tube and an axle side tube are inserted into each other, a gas chamber is attached to the vehicle body side tube and the axle side tube, and a supply / exhaust valve for adjusting the pressure of the gas chamber is attached. The mounting direction along the axial direction of the valve intersects with the direction of inertial force due to the expansion / contraction stroke of the front fork. Thereby, the gas leakage of the air supply / exhaust valve due to the expansion / contraction stroke of the front fork can be prevented.

10 front fork 11 vehicle body side tube 12 axle side tube 31 fork bolt (upper end closing member)
34 Bottom bolt (lower end closing member)
50 Inner air spring chamber (gas chamber)
51 Supply / exhaust valve 60 Outer air spring chamber (gas chamber)
61 Supply / exhaust valve 70 Rebound air spring chamber (gas chamber)
80 Sub tank 81 Air chamber (gas chamber)
94 Supply / Exhaust Valve

Claims (6)

Insert the vehicle body side tube and the axle side tube into each other,
A gas chamber is attached to the vehicle body side tube and the axle side tube,
In the front fork equipped with a supply / exhaust valve that adjusts the pressure in the gas chamber,
A front fork characterized in that the mounting direction along the axial direction of the air supply / exhaust valve intersects with the direction of the inertial force due to the expansion / contraction stroke of the front fork.   The front fork according to claim 1, wherein the gas chamber is an air spring chamber.   The front fork according to claim 1 or 2, wherein the supply / exhaust valve is closed by pressing a valve body biased by a spring against a valve seat of a valve core.   The front fork according to any one of claims 1 to 3, wherein the air supply / exhaust valve is attached to an upper end closing member of a vehicle body side tube.   The front fork according to any one of claims 1 to 3, wherein the air supply / exhaust valve is attached to a lower end closing member of an axle side tube.   The front fork according to any one of claims 1 to 3, wherein the supply / exhaust valve is attached to a sub tank provided outside the vehicle body side tube and the axle side tube.

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