JP6343213B2 - Front fork - Google Patents

Description

  The present invention relates to a front fork, and more particularly to an improvement in a front fork that is mounted on the front wheel side of a motorcycle and absorbs vibration during traveling.

  In recent years, instead of using a coil spring as a suspension spring for a front fork, a front fork using a so-called air spring as a suspension spring has been developed that encloses air of a predetermined pressure and energizes the front fork in the extending direction. ing.

  In the front fork using an air spring, the weight of the entire front fork can be reduced by not using a metal coil spring. Also, in the case of an air spring, air can be enclosed from an air valve provided at one end of the front fork to adjust the air pressure in the front fork, so that the vehicle height can be adjusted easily.

  However, in the front fork using such an air spring, when the oil seal provided at the opening end of the inner periphery of the outer tube is deteriorated, the air is exposed to the outside from the gap between the outer tube and the inner tube. There is a possibility of leakage.

  Specifically, using FIG. 3, hydraulic oil is supplied from the oil chamber R in the fork to the gap S between the outer tube 1 and the inner tube 2 to realize smooth movement of the inner tube 2 and the outer tube 3. Therefore, the communication hole 10 is provided in the inner tube 2. However, in this way, in the compression stroke in which the inner tube 2 is inserted into the outer tube 1, the gap S is enlarged, and the air enclosed in the air chamber G flows through the communication hole 10 together with the hydraulic oil. . Since the hydraulic oil is viscous, during this compression stroke, the hydraulic oil immediately above the oil seal 4 is lifted by the movement of the inner tube 2 and air enters directly above the oil seal 4. As described above, since the air reaches the oil seal 4, if the oil seal 4 is deteriorated, the air may be slightly leaked.

  If air is not leaked to the outside and the air is not replenished for a long time, the reaction force of the predetermined air spring becomes weak, the vehicle height of the two-wheeled vehicle is lowered, and the riding comfort may be impaired.

  Therefore, there have been proposals for preventing problems such as air leaking to the outside through the oil seal and impairing riding comfort.

  For example, in the proposal disclosed in the cited document 1, an oil seal provided at an opening end of a gap between an outer tube and an inner tube and a liquid reservoir chamber adjacent to the oil seal are defined, and the liquid reservoir Since the stored liquid is stored in the chamber, when the oil seal is deteriorated, the stored liquid stored in the liquid pool chamber leaks to the outside first, so that the deterioration of the oil seal can be detected before the air leaks. .

JP2012-107680

  However, the proposal disclosed in Cited Document 1 detects in advance before air leaks and prevents problems such as a loss of ride comfort due to air leaks by means such as stopping the use of a motorcycle. The leak has not been prevented.

  Accordingly, an object of the present invention is to provide a front fork that is less likely to cause air leakage even if the oil seal is deteriorated, maintains a predetermined vehicle height in a motorcycle, and does not impair riding comfort. .

Means for solving the problems are as follows:
In the gap between the outer tube and the inner tube, an annular oil seal that is fixed to the inner periphery in the axial direction of the opening end of the outer tube, and a washer is provided on the inner side in the axial direction of the oil seal, and the washer By providing a bearing at a position spaced apart from each other, an oil reservoir chamber for storing hydraulic oil is formed between the washer and the bearing.

  According to the above configuration, since a large amount of hydraulic oil is stored immediately above the oil seal, air that has entered the gap between the outer tube and the inner tube can be prevented from reaching the oil seal, and air leakage Can be prevented.

  As a result, even if the oil seal is deteriorated, the occurrence of air leakage is less likely to occur, and the predetermined vehicle height maintenance and riding comfort of the two-wheeled vehicle can be achieved.

It is a longitudinal cross-sectional view of the front fork which concerns on this Embodiment. FIG. 2 is a partially enlarged longitudinal sectional view of the front fork shown in FIG. 1. It is a longitudinal cross-sectional view of the front fork which concerns on the conventional form.

  Below, based on this illustrated embodiment, it demonstrates, referring drawings. The same reference numerals given throughout the several drawings indicate the same or corresponding parts.

  As shown in FIG. 1, the front fork according to the present embodiment includes a fork main body 3 including an outer tube 1 and an inner tube 2 that is inserted into the outer tube 1 so as to be axially movable. An air spring G is formed by enclosing air in the main body 3 and urges the fork main body 3 in the extending direction, and is fixed to the inner periphery of the opening end of the outer tube 1. From an annular oil seal 4 slidably contacting the outer periphery, a washer 5 provided on the inner periphery of the outer tube 1 in the axial direction from the oil seal 4, and the washer 5 provided on the inner periphery of the outer tube 1 An annular bearing 6 provided inside the axial direction and spaced apart from the washer 5 and in sliding contact with the outer periphery of the inner tube 2, and the outer Wherein the over tube 1 a gap S between the inner tube 2, hydraulic fluid is constituted by a reservoir chamber O that is stored is provided between the said washer 5 bearing 6.

  The front fork is mainly mounted on the front wheel side of the motorcycle and holds the front wheel. Incidentally, although not shown in the figure, the front fork is mounted on the front wheel side of the two-wheeled vehicle, the upper side of the two front forks on the left and right are connected by the upper bracket and the under bracket, and the inner tube 2 of each front fork is connected. The lower end is connected to the axle of the front wheel and suspended so as to sandwich the front wheel.

  As shown in FIG. 1, the front fork according to the present embodiment includes a fork main body 3 including an outer tube 1 and an inner tube 2 that is inserted into the outer tube 1 so as to be movable in the axial direction. And a damper 12 housed therein. The damper 12 includes a cylinder 13 whose lower end in FIG. 1 stands at the bottom of the inner tube 2, a piston (not shown) that is slidably inserted into the cylinder 13 and divides the inside of the cylinder 13 into two pressure chambers, and one end thereof. A piston rod 14 that is connected to the piston and whose upper end in the figure is connected to the top of the outer tube 1 is provided.

  The fork main body 3 has an oil chamber R in which a predetermined amount of hydraulic oil is stored, and an air chamber G defined by the oil surface of the hydraulic oil as a boundary. The air spring formed in the air chamber G urges the fork main body 3 in the extending direction. When this front fork is interposed between the motorcycle body and the wheels, the vehicle body is elastically supported by an air spring.

  Note that an air valve is provided at one end of the fork main body 3, and the pressure in the air chamber G can be adjusted via the air valve, so that the vehicle height can be easily adjusted.

  Furthermore, since the fork main body 3 is urged in the extending direction by the air spring formed in the air chamber G in the front fork of the present invention, for example, compared to the case where the coil spring is provided in the fork main body 3 as a suspension spring, The weight of the entire front fork can be reduced by not using a metal coil spring.

  Although not shown in detail, when the front fork extends and retracts from the cylinder 13 in the forward / backward direction, the two pressure chambers in the cylinder 13 defined by the piston are operated through a damping valve provided in the piston. Oil moves.

  Further, when the piston rod 14 moves in the retracting direction from the cylinder 13, the operating oil corresponding to the volume of the retracted piston rod 14 is insufficient in the cylinder 13, so that only movement of the operating oil into the cylinder 13 is allowed. Insufficient hydraulic oil is supplied from the oil chamber R into the cylinder 13 via an unillustrated extension check valve.

  On the other hand, when the piston rod 14 moves in the direction of entry into the cylinder 13, the hydraulic oil corresponding to the volume of the rod that has entered becomes surplus in the cylinder 13, and this surplus hydraulic oil is used as the hydraulic oil cylinder 13. The oil is discharged from the cylinder 13 to the oil chamber R through a pressure-side damping valve (not shown) that allows only outward movement.

  Therefore, the damper 12 generates a damping force due to the resistance when hydraulic oil passes through the piston and each valve (not shown) when the front fork extends and retracts in the cylinder 13 in the forward / backward direction. Suppresses the expansion and contraction of the fork. A change in the volume of the cylinder 13 corresponding to the volume of the piston rod 14 that moves forward and backward in the cylinder 13 is compensated by the oil chamber R.

  As shown in FIGS. 1 and 2, the front fork according to the present embodiment is inserted into the outer tube 1 so that the inner tube 2 is movable in the axial direction. The outer diameter of the inner tube 2 is larger. Therefore, a gap S is formed between the outer tube 1 and the inner tube 2.

  As shown in FIGS. 1 and 2, in the gap S, an annular bearing 11 that is attached to the inner periphery of the outer tube 1 and is in sliding contact with the outer periphery of the inner tube 2, and the open end of the outer tube 1. The annular oil seal 4 and the annular dust seal 7 that are fixed to the inner periphery of the inner tube 2 and are in sliding contact with the outer periphery of the inner tube 2, and the inner periphery of the outer tube 1, the inner side of the oil seal 4 in the axial direction. A cylindrical spacer 9 provided adjacent to the spacer 9, a washer 5 provided adjacent to the spacer 9, and an inner side in the axial direction from the inner washer 5 of the outer tube 1, at a position separated from the washer 5. An annular bearing 6 that is provided and slidably contacts the outer periphery of the inner tube 2 is provided, and an oil reservoir chamber O in which hydraulic oil is stored is formed between the washer 5 and the bearing 6.

  In addition, the clearance S allows the working oil in the fork main body 3 to flow in through the communication hole 10 that communicates the clearance S with the inside of the fork main body 3 provided in the inner tube 2. Thus, the axial movement of the outer tube 1 and the inner tube 2 is made smooth. In the compression stroke in which the inner tube 2 is inserted into the outer tube 1, the air enclosed in the air chamber G flows into the increasing gap S through the communication hole 10. Air is mixed.

  As shown in FIG. 2, the inner periphery of the outer tube 1 constituting the gap S has an inner diameter portion 1c formed by expanding the diameter at the lower opening end side in the drawing, and a lower portion in the drawing from the middle diameter portion 1c. A large-diameter portion 1d that is further expanded on the opening end side is provided. As described above, the middle diameter portion 1 c and the large diameter portion 1 d are provided on the inner periphery of the outer tube 1, so that step portions 1 a and 1 b are also formed on the inner periphery of the outer tube 1.

  As shown in FIGS. 1 and 2, the bearing 6 is fitted to the intermediate diameter portion 1c via the holding member 15 that holds the bearing 6, and is attached to the outer tube 1 and contacts the step portion 1b. The step 1b regulates the movement toward the sealing side, which is the upper side in FIG. In addition, the bearing 6 is in sliding contact with the outer periphery of the inner tube 2. Further, the washer 5 is fitted to the large-diameter portion 1d, is attached to the outer tube 1 and is in contact with the step portion 1a, and the step portion 1a allows the movement to the sealing side, which is the upper side in FIG. It is regulated. Further, a spacer 9 and an oil seal 4 are stacked from above, and are prevented from coming off by a snap ring 8. In this way, the washer 5, the spacer 9, and the oil seal 9 are sandwiched between the step portion 1a and the snap ring 8, and are fixed so as not to move in the axial direction. Further, the dust seal 7 is press-fitted and fixed to the inner periphery of the distal end of the large-diameter portion 1 d of the outer tube 1.

  Hereinafter, members provided in the gap S will be described in detail.

  As shown in FIG. 2, the oil seal 4 according to the present embodiment has an annular insert metal 4 c inside, and extends in the inner diameter direction from the base 4 a and the base 4 a that are fixed to the inner periphery of the outer tube 1. And a seal portion 4b that is in sliding contact with the outer periphery of the inner tube 2.

  Further, a base 4a is provided by an annular washer 5 and a spacer 9 fixed to the upper sealing side of the oil seal 4 in the drawing, and a snap ring 8 provided adjacent to the lower opening end side of the oil seal 4 in the drawing. The oil seal 4 is fixed to the outer tube 1. In addition, since the base portion 4a of the oil seal 4 is provided with an annular insert metal 4c, it can be firmly fixed to the outer tube 1 when it is press-fitted into the outer tube 1.

  The oil seal 4 scrapes off the working oil attached to the outer periphery of the inner tube 2 during the extension process in which the inner tube 2 is withdrawn from the outer tube 1 to prevent leakage of the working oil to the outside. At the same time, since the inner diameter of the oil seal 4 is smaller than the outer diameter of the inner tube 2, the gap S between the outer tube 1 and the inner tube 2 is sealed to prevent air leakage.

  As shown in FIG. 2, the dust seal 7 according to the present embodiment includes an insert metal 7c having an L-shaped cross section, and a base portion 7a fixed to the inner periphery of the distal end of the large diameter portion 1d of the outer tube 1, and a base portion A seal portion 7b extending in the inner diameter direction from 7a and slidably contacting the outer periphery of the inner tube 2 is provided.

  Further, the base portion 7a of the dust seal 7 has a flange portion 7d extending outward and outward in accordance with the shape of the insert metal 7c, and the flange portion 7d is brought into contact with the opening end portion of the outer tube 1. The base 7a is press-fitted into the inner periphery of the distal end of the large-diameter portion 1d of the outer tube 1 so that the dust seal 7 is fixed.

  The dust seal 7 scrapes off dust such as dust and dust attached to the outer periphery of the inner tube 2 during the compression stroke in which the inner tube 2 is inserted into the outer tube 1, and removes dust into the fork. Prevents intrusion.

  Further, since the base portion 7 a of the dust seal 7 includes an annular insert metal 4 c inside, the base portion 7 a can be firmly fixed to the outer tube 2 when pressed into the outer tube 2.

  In addition, since the insert metal 7 c is provided, the base portion 7 a is in close contact with the inner periphery of the outer tube 1 and the opening end portion of the outer tube 1, and the dust seal 7 seals the inner periphery of the outer tube 1.

  Although the oil seal 4 and the dust seal 7 are separated in the drawing, the oil seal 4 and the dust seal 7 may be an integral seal.

  As shown in FIG. 2, the washer 5 is fitted to the large diameter portion 1d provided on the inner periphery of the outer tube 1, and the cylindrical spacer 9 and the oil seal 4 are laminated from above. Each part is fixed between the snap ring 8 and the stepped part 1b.

  Since the spacer 9 abuts only on the base portion 4a of the oil seal 4 having the insert metal 4c, the base portion 4a does not deform. For example, the seal portion 4b extends to the sealing side from the abutting portion of the base portion 4a with the spacer 9. Even if it does, there is no fear of damaging the seal part 4b of the oil seal 4.

  In addition, when replacing the oil seal 4 and the bearings 6 and 11 in the front fork according to the present embodiment, first, the dust seal 7 and the snap ring 8 are removed, and then the inner tube 2 is withdrawn from the outer tube 1. Pull on. Thereby, since the bearing 11 mounted on the outer periphery of the inner tube 2 presses the bearing 6 mounted on the inner periphery of the outer tube 1, the bearing 6 comes off from the inner periphery of the outer tube 1 and is removed. Comes into contact with the washer 5. When pulled further, the bearing 11 pushes the washer 5 together with the bearing 6, the spacer 9 and the oil seal 4 are also pushed, and each component is removed.

  Also here, since the spacer 9 is in contact only with the base 4a of the oil seal 4, there is no possibility of damaging the seal 4b of the oil seal 4 when the oil seal 4 is taken out.

  In this embodiment, the spacer 9 is provided. However, if the spacer 9 is omitted and the washer 5 directly contacts the oil seal 4, the spacer 9 can be omitted. When the spacer 9 is omitted, it is possible to reduce the labor and the number of parts to be assembled.

  As shown in FIGS. 1 and 2, the annular bearing 6 according to the present embodiment is fitted to a middle diameter portion 1 c provided on the inner periphery of the outer tube 1 via a holder portion 15, and The annular bearing 11 is provided in the lower part of the inner periphery of the tube 1 in the drawing, and is provided in the upper part of the outer periphery of the inner tube 2 so as to be separated from the bearing 6. Since the bearings 6 and 11 are in sliding contact with the outer periphery of the inner tube 2 and the inner periphery of the outer tube 1, the bearings 6 and 11 are connected to the inner tube 2 when the inner tube 2 moves in the axial direction in the outer tube 1. The tube 2 is guided to prevent the inner tube 2 from being eccentric.

  As shown in FIG. 2, the bearing 6 is fixed to the inner periphery of the outer tube 1 via a holder member 15. Moreover, the stopper part 15a extended toward an inner peripheral radial direction is formed in the seal | sticker side edge part of the holder member 15, Thereby, the bearing 6 can be positioned in the case of an assembly. Further, since the bearing 6 is fixed to the outer tube 1 via the holder member 15, the diameter of the gap S between the outer tube 1 and the inner tube 2 is increased by the amount of the holder member 15, and an oil sump described later. The volume of the chamber O becomes large, and a large amount of hydraulic oil can be stored in the oil reservoir chamber O.

  Further, in the present embodiment, since the bearing 6 is held by the holder member 15 and the diameter of the gap S is increased, the conventional bearing can be used as it is simply by newly providing the holder member 15.

  Note that the thickness of the bearing 6 may be a size obtained by combining the thickness of the holder member 15 according to the present embodiment and the thickness of the bearing 6. In this case, in order to fix the bearing 6 to the inner periphery of the outer tube 1. In addition, it is not necessary to use the holder member 15. However, in order for the present invention to be effective, it is not always necessary to increase the thickness of the bearing 6.

  As shown in FIG. 2, since the bearing 6 is provided at a position separated from the washer 5, an oil reservoir chamber O in which hydraulic oil is stored is formed between the washer 5 and the bearing 6. Therefore, a large amount of hydraulic oil can always be stored immediately above the oil seal.

  The distance between the washer 5 and the bearing 6 may be set as appropriate depending on conditions such as the viscosity of the hydraulic fluid to be filled.

  Hereinafter, the operation and effect of the front fork according to the present embodiment will be described.

  When vibration is input from the side connected to the front wheel of the inner tube 2, the inner tube 2 is inserted into the outer tube 1, and the damper 12 housed in the fork main body 3 contracts, and the fork main body 3. Damping force is generated to prevent the expansion and contraction of the material.

  In addition, in the compression stroke in which the inner tube 2 is inserted into the outer tube 1, the hydraulic oil contained in the oil chamber R is used to compensate for the increasing volume of the gap S between the outer tube 1 and the inner tube 2. However, it flows into the gap S through the communication hole 10 provided in the inner tube 2.

  Further, since the oil reservoir chamber O capable of storing a large amount of hydraulic oil is formed between the washer 5 and the bearing 6 in the gap S, the inner tube is affected by the viscosity of the hydraulic oil during the compression stroke of the front fork. 2, even if the hydraulic oil moves out of the oil reservoir O, the hydraulic oil does not run short and the air in the air chamber G that has flowed into the gap S through the communication hole 10 is oil. It is difficult to reach directly above the seal 4.

  Therefore, even if the oil seal 4 has deteriorated, air leakage is unlikely to occur.

  Further, since the gap between the bearing 6 and the inner tube 2 is extremely narrow, the hydraulic oil in the oil reservoir chamber O is difficult to move from the bearing 6 to the upper sealing side in the figure due to sliding of the inner tube 2. Since a large amount of hydraulic oil is stored in the reservoir chamber O, there is no risk of exhaustion due to sliding of the inner tube 2.

  The preferred embodiments of the present invention have been described in detail above, but it goes without saying that modifications, changes and modifications can be made without departing from the scope of the claims.

1 Outer tube 2 Inner tube 3 Fork body 4 Oil seal 5 Washer 6 Bearing O Oil reservoir

Claims (1)

A fork main body comprising an outer tube and an inner tube inserted into the outer tube so as to be axially movable;
An air spring formed by enclosing air in the fork main body, and urging the fork main body in the extending direction;
An annular oil seal fixed to the inner periphery of the opening end of the outer tube and in sliding contact with the outer periphery of the inner tube;
A washer provided on the inner circumference of the outer tube and on the inner side in the axial direction from the oil seal;
An annular bearing that is provided in an axially inner side from the washer on the inner periphery of the outer tube and is spaced from the washer, and is in sliding contact with the outer periphery of the inner tube;
A front fork comprising an oil reservoir chamber which is a gap between the outer tube and the inner tube and is provided between the washer and the bearing and stores hydraulic oil.

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