JP2007278333A - Front fork - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately fill adhesive in a gap between an axle bracket and a wheel side tube when using the adhesive for connecting the axle bracket approximately to the lower end of the wheel side tube. <P>SOLUTION: Between the lower end of the wheel side tube 1 and the bottom of the axle bracket 2, a seal case 3 is held whose outer periphery is opposed to the inner periphery of the opening end of the wheel side tube 1. A seal member is held on the seal case 3 for revolving in close contact with the inner periphery of the opening end of the wheel side tube 1. A space between a rising portion 21 of the axle bracket 2 and the lower end 11 of the wheel side tube 1 is communicated with the outside via an air ventilation duct. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a front fork, and more particularly, to an improvement in a front fork that is mounted on a front wheel side of a bicycle that is a two-wheeled vehicle and that suspends a front wheel at a lower end portion.

  In the case of a bicycle as a recent motorcycle, for example, from the viewpoint of advantageous long-time driving and off-road driving, or from reducing the burden during handling such as parking and transportation, as much as possible The company plans to reduce the vehicle weight.

  Especially for off-road bicycles, in order to improve riding comfort, not only cushion units such as dampers and springs are mounted on the rear wheel side, but also function as a hydraulic shock absorber on the front wheel side. The front fork is supposed to be mounted.

  By the way, with regard to mounting a front fork on the front wheel side of a bicycle, a bicycle whose weight is significantly reduced compared to a motorcycle by simply reducing the size of the front fork that has been developed for the same motorcycle. It may be pointed out that when it is mounted on the front wheel side, it does not necessarily contribute to weight reduction in a bicycle.

  Therefore, as a measure for reducing the weight of the front fork, for example, as disclosed in Patent Document 1, a vehicle body side tube and a wheel side tube, which are constituent parts of the front fork, are made of, for example, a carbon fiber reinforced plastic (hereinafter referred to as a carbon fiber reinforced plastic). It will be proposed to form a pipe (abbreviated as CFRP).

  When the wheel side tube is formed of a CFRP pipe, an axle bracket is often connected to the wheel side tube using an adhesive as disclosed in Patent Document 1 above. It is supposed to.

  This is because, in the conventional front fork in which the wheel side tube is made of a metal pipe, for example, as shown in Patent Document 2, the axle bracket is screwed to the lower end portion of the wheel side tube. This is based on the fact that since both are made of a metal material, it is possible to easily form threads on the outer periphery of the lower end portion of the wheel side tube and the inner periphery of the rising portion of the axle bracket.

On the other hand, when connecting the axle bracket to the wheel side tube, either by using an adhesive or by screwing, hydraulic oil leaks from the inside of the wheel side tube. It is absolutely necessary to prevent this, and from that point of view, in either Patent Document 1 or Patent Document 2, a seal member is disposed between the wheel side tube and the axle bracket so-called liquid tightness. Is guaranteed.
JP 2005-265129 A (paragraphs 0028 and 0040 in the specification, FIG. 6) Japanese Patent Laying-Open No. 2003-222177 (paragraph 0018 in the specification, FIG. 2)

  However, when the axle bracket is connected to the wheel side tube, whether the wheel side tube is made of a metal pipe or the above-mentioned CFRP pipe, there is a problem with the use of the adhesive itself. While it can be said that it is not, there may be a slight problem with the location of the seal member.

  That is, as disclosed in Patent Document 1, the seal member that prevents leakage of hydraulic oil from the inside that is the inside of the wheel side tube is disposed on the outer periphery of the lower cap of the housing on the inside of the lower end portion of the wheel side tube. It is assumed that it is arranged so as to be in close contact with the inner periphery of the lower end portion of the wheel side tube while being housed in the formed annular groove.

  Therefore, in the case of being disclosed in this Patent Document 1, the adhesive injected between the rising portion of the axle bracket and the lower end portion of the wheel side tube is not only this part but also the wheel side tube. There is a problem that it will penetrate between the lower cap and, in other words, an extra adhesive is required.

  Therefore, even when the wheel side tube is made of a CFRP pipe, as disclosed in Patent Document 2, the seal member is accommodated in an annular groove formed on the inner periphery of the rising portion of the axle bracket made of a metal material. However, it is preferable to be in close contact with the outer periphery of the lower end portion of the wheel side tube. In this case, it is possible to avoid the inconvenience that the adhesive material described above penetrates to the inside of the wheel side tube. Become.

  However, when injecting the adhesive between the rising part of the axle bracket and the lower end of the wheel side tube, the adhesive is injected between the upper end of the rising part of the axle bracket and the wheel side tube. In this case, the seal member is positioned near the opening end of the wheel side tube, so that the situation that the air that cannot flow out to the outside is sealed is called the seal member. However, there is a risk of inadequate adhesion.

  The present invention was devised in view of the above-described circumstances, and its object is to roughly connect the axle bracket to the wheel side when the axle bracket is connected to the lower end of the wheel side tube by using an adhesive. A front fork that can realize a complete adhesion state by ensuring that the adhesive injected between the tubes is filled in the gap between the two, and that can be expected to improve its versatility, that is, the front wheel side of the bicycle It is to provide a front fork that is optimal for being mounted on the vehicle.

  In order to achieve the above object, the structure of the front fork according to the present invention is basically arranged inside the rising portion formed in a cylindrical shape extending in the axial direction of the wheel side tube forming the fork body together with the vehicle body side tube. It has an axle bracket that is connected to the lower end of the wheel side tube in a fixed state under the use of adhesive while the lower end of the wheel side tube is present, and this axle bracket is continuously formed at the lower end of the rising part, In a front fork having a bottom portion that supports a lower end serving as an opening end of a tube, the outer periphery is opposed to the inner periphery of the opening end portion of the wheel side tube between the lower end of the wheel side tube and the bottom portion of the axle bracket. A seal case is sandwiched and the seal case circulates in close contact with the inner periphery of the opening end of the wheel side tube. Seal member is held, and between the lower end of the rising portion and the wheel side tube of the axle bracket is in communication with the outside through an air vent channel.

  Therefore, in the present invention, bonding is performed between the lower end portion of the wheel side tube that forms the fork main body together with the vehicle body side tube, and the cylindrical rising portion of the axle bracket interposed on the outer periphery of the lower end portion. When injecting the material, the gap is infused so that the gap is communicated to the outside through the air vent channel, so there is no risk of air remaining in the gap due to the injection of the adhesive. It does not cause a bonding failure state without expressing a portion where the adhesive is not filled.

  Hereinafter, the present invention will be described based on the illustrated embodiment. The front fork shown in FIG. 1 is mounted on the front wheel side of a bicycle as a two-wheeled vehicle and suspends the front wheel at the lower end portion. A suspension spring as a spring element is accommodated in a fork main body composed of the wheel side tube 1 and the fork main body is urged in the extending direction by the urging force of the suspension spring.

  The front fork has a damper at the shaft core portion of the fork main body, and the damper expands and contracts in synchronization with the expansion and contraction operation of the fork main body. It functions as a hydraulic shock absorber that absorbs road surface vibrations input to the front wheels.

  By the way, in this front fork, it is not required that the fork main body and the damper have a special configuration. Therefore, the respective configurations of the fork main body and the damper are set upright or inverted. A well-known structure may be adopted including whether it is set in the mold.

  This is because the present invention intends to prevent the occurrence of an adhesion failure state when an axle bracket 2 described later is connected to the wheel side tube 1 in a fixed state using an adhesive. Whether the wheel side tube 1 is made of a large diameter outer tube or the fork body is made upside down and the wheel side tube 1 is made of a small diameter inner tube is basically a problem. Because it will not be.

  In addition, when the fork body is set to a so-called inverted type, the outer tube is a vehicle body side tube and connected to the handle side of the bicycle, and the inner tube is the wheel side tube 1 to connect the front wheel of the bicycle. The unsprung load can be reduced by reducing the so-called lower end mass of the front fork, which is advantageous in improving the handleability of the bicycle.

  By the way, what is shown in the figure shows a case where the fork body is an inverted type, and therefore the wheel side tube 1 is made of an inner tube. In this embodiment, the wheel side tube 1 is made of a CFRP pipe. The metal axle bracket 2 is connected in a fixed state using an adhesive, that is, fixed.

  Thus, by assuming that the wheel side tube 1 is made of a CFRP pipe, when this is a component of the fork main body, it will be understood that it has mechanical strength as an axial member, at least, This contributes to weight reduction in the fork body as compared to the case where it consists only of metal material, and contributes to weight reduction in a bicycle in which the front fork having this fork body is mounted on the front wheel side. become.

  Therefore, from the viewpoint of contributing to weight reduction in the bicycle, it is preferable that the vehicle body side tube that constitutes the fork body together with the wheel side tube 1 is also made of CFRP pipes to reduce its weight. Become.

  Incidentally, when the vehicle body side tube is also made of a CFRP pipe, it is preferable that the vehicle body side tube is formed by integrally connecting a metal pipe to the inner periphery of the CFRP pipe.

  When the vehicle body side tube is formed by integrally connecting a metal pipe to the inner periphery of the CFRP pipe, the wheel side tube 1 is connected to a cylindrical member made of a metal material at the upper end portion, for example. The bush member is interposed on the outer periphery of the member, and the outer periphery of the bush member is slidably contacted with the inner periphery of the metal pipe in the vehicle body side tube. It is preferable that the vehicle body side tube is slidably brought into contact with the inner periphery of the vehicle body side tube so that the wheel side tube 1 does not appear in or out of the vehicle body side tube in a so-called inclined state.

  In addition, when the opening end part in the vehicle body side tube through which the wheel side tube 1 is inserted and retracted has a bush member on the inner periphery, and this bush member is brought into sliding contact with the outer periphery of the wheel side tube 1, The bush member together with the bush member held on the wheel side tube 1 side will constitute a bearing structure in the fork main body.

  In the wheel side tube 1, the metal pipe may be integrally connected to the outer peripheral portion where the bush member held on the inner periphery of the opening end portion of the vehicle body side tube is in sliding contact. In this case, when the metal pipe extends to the location where the axle bracket 2 to be described later is disposed, it prevents bending and breakage due to the concentration of bending stress in the wheel side tube 1 resulting from the connection of the axle bracket 2. It will be effective.

  Next, in this front fork, the axle bracket 2 is fixed to the lower end portion 11 of the wheel side tube 1. The axle bracket 2 is formed in a cylindrical shape, that is, the outer periphery of the lower end portion 11 in the wheel side tube 1. The lower end portion 11 of the wheel side tube 1 is made to be present inside the rising portion 21 formed in a cylindrical shape extending in the axial direction of the wheel side tube 1 so that the wheel side tube 1 is introduced in this state. The adhesive material is injected between the outer periphery of the lower end portion 11 and the inner periphery of the rising portion 21 of the axle bracket 2 and connected in a fixed state, that is, the two are integrated.

  At this time, the axle bracket 2 is made of a light metal material such as an aluminum material so as to contribute to weight reduction in the fork main body, and an axle for connecting the front wheel shaft of the bicycle to the rising portion 21 at this time. The grip portion 22 and the brake caliper portion 23 that connects the brake mechanism are integrally connected.

  Therefore, in this axle bracket 2, the lower end portion 11 of the wheel side tube 1 is introduced inside the rising portion 21 of the axle bracket 2, and an adhesive made of, for example, an epoxy resin is interposed between the two. By injecting and integrating the two, it is possible to prevent the so-called rattling from occurring between the lower end portion 11 of the wheel side tube 1 and to reliably suspend the front wheel of the bicycle on the front fork. In addition, it is possible to effectively prevent the axle bracket 2 from rotating in the circumferential direction on the outer periphery of the lower end portion 11 of the wheel side tube 1 and to eliminate the inconvenience of water intrusion between the two.

  By the way, in connecting the axle bracket 2 to the lower end part 11 of the wheel side tube 1, in FIG. 1, ie, in the place shown in FIG. 2, the opening end used as the lower end in the figure of the wheel side tube 1 is It is supposed that the bottom portion 24 of the axle bracket 2 is closed, and at this time, a seal case 3 to be described later is sandwiched between the bottom portion 24 and a lower end as an opening end of the wheel side tube 1 in a fixed state. .

  And in connecting the axle bracket 2 to the lower end part 11 of the wheel side tube 1, the opening end of the wheel side tube 1 was screwed to the bottom part 24 of the axle bracket 2 as shown in FIG. In this case, the bottom portion 22 of the axle bracket 2 sandwiches the seal case 3 between the lower end of the wheel side tube 1 in a fixed state.

  On the other hand, the seal case 3 has a main body 31 that is formed in an annular shape and is present inside the opening end of the wheel-side tube 1, and a lower outer peripheral portion of the main body 31 is formed in a flange shape. It is assumed that it is the heel part 32.

  And in this seal case 3, the main-body part 31 has the circumferential annular groove 31a formed in the circumferential direction on the outer periphery, and an outer periphery is the opening end part of the wheel side tube 1 in this annular groove 31a. It is assumed that the seal member 5 made of, for example, an O-ring is held around the inner periphery closely.

  And in this seal case 3, the main-body part 31 exists in the bottom part 24, and the lower end surface which opposes the upper end surface of the bottom cover part 24a which obstruct | occludes the opening end of the wheel side tube 1 substantially. The annular concave groove 31b is formed in the circumferential direction, and the outer circumference of the annular concave groove 31b circulates in close contact with the upper end surface of the bottom lid portion 24a of the bottom portion 24. The seal member 6 is held.

  Further, in this seal case 3, the flange portion 32 is sandwiched between the lower end of the wheel side tube 1 and the bottom portion 24 of the axle bracket 2, thereby bringing the seal case 3 to a predetermined position. It is going to be fixed.

  Therefore, for fixing the seal case 3 to the inner periphery of the opening end portion of the wheel side tube 1, for example, when threads are formed on the wheel side tube 1 side and the seal case 3 side, and both are screwed together, Compared with the case where it does, it can reduce the effort which a part process requires significantly, and it contributes to the reduction in product cost by suppressing the rise in part cost.

  Not only that, it is difficult to say that it is impossible to form a thread on the inner periphery of the wheel-side tube 1 made of CFRP pipe by, for example, post-processing. In view of the fact that the formation of a thread on the inner periphery of 1 causes a significant increase in the cost of parts, the fixing of the seal case 3 to a predetermined position is the bottom of the wheel side tube 1 and the bottom of the axle bracket 2. It can be said that the effect of the clamping with the part 24 is unreasonably large.

In the lower end portion of the fork main body having the seal case 3 formed as described above, that is, while the lower end portion 11 of the wheel side tube 1 is introduced inside the rising portion 21 of the axle bracket 2, When injecting the adhesive into the two and integrating the two, as described above, air remains between the two and the part where the adhesive cannot be surrounded is expressed, that is, the adhesive failure state is expressed. That must be strictly prevented,
Therefore, in the present invention, when the adhesive material is injected between the rising portion 21 of the axle bracket 2 and the lower end portion 11 of the wheel side tube 1, the air between the two is discharged to the outside through the air vent channel. As shown in FIG. 2, the air vent channel is formed in the bottom portion 24 of the axle bracket 2, that is, the perforated hole 24b.

  3, the air vent channel is formed between the bottom portion 24 of the axle bracket 2 and the lower cap member 4 connected to the bottom portion 24, that is, screwed. It is said.

  That is, the air vent channel shown in FIG. 3 is formed by a thread gap formed by the thread 24 c of the bottom portion 24 of the axle bracket 2 and the thread 4 a of the lower cap member 4.

  Therefore, in the case where the air vent channel is formed by the above-described screw gap, it is possible to save the labor required for parts processing as compared with the case where it is bothered to perforate the bottom portion 24 as in the perforation 24b. It will be.

  3, it is assumed that the outer periphery of the guide portion 41 that is the upper end portion of the lower cap member 4 is in close contact with the distribution of the seal member 7 on the inner periphery of the annular seal case 3. It is said that the pressure loss between the two is prevented.

  In the seal case 3 formed as described above, as shown in FIG. 2, the oil pressure from the inside of the wheel side tube 1 by the seal members 5 and 6 held by the main body 31, that is, the hydraulic oil is the so-called wheel side. This prevents the tube 1 from coming out.

  The seal case 3 shown in FIG. 3 is operated from the inside of the wheel side tube 1 by the seal member 5 held by the main body 31 in cooperation with the seal member 7 held by the guide portion 41 of the lower cap member 4. Is prevented from slipping out of the wheel side tube 1.

  And when the sealing members 5, 6, and 7 are functioning as described above, by injecting an adhesive between the rising portion 21 of the axle bracket 2 and the lower end portion 11 of the wheel side tube 1, Of course, this adhesive does not flow into the inside of the wheel-side tube 1, and at this time, the gap into which the adhesive is injected is communicated to the outside through the air vent channel. It does not remain so that air is contained in the gap to be injected, and it is possible to prevent the occurrence of an adhesion failure state in which a portion where the adhesive cannot be surrounded appears.

  By the way, as for the injection of the adhesive material, any injection is possible as long as the adhesive material can be filled in a so-called complete state between the rising portion 21 of the axle bracket 2 and the lower end portion 11 of the wheel side tube 1 as a predetermined portion. A method may be selected.

  Therefore, for example, as indicated by an arrow a in FIG. 1, the adhesive may be injected from the upper end between the rising portion 21 of the axle bracket 2 and the lower end portion 11 of the wheel side tube 1, and FIG. A horizontal hole 21a is opened in the rising portion 21 of the axle bracket 2 as shown by a broken line inside, and an adhesive is injected using the horizontal hole 21a as shown by a broken line arrow b. good.

  And when utilizing said horizontal hole 21a, it confirms that an adhesive material will leak from the upper end between the standing part 21 of said axle bracket 2, and the lower end part 11 of the wheel side tube 1. In addition, by confirming that the adhesive material leaks from the so-called lower air vent channel, the adhesive material is provided between the rising portion 21 of the axle bracket 2 and the lower end portion 11 of the wheel side tube 1. It can be confirmed that is completely filled.

  Incidentally, in the place shown in FIG. 3, the lower cap member 4 is integrated with the bottom portion 24 of the axle bracket 2 by an adhesive and cannot be removed. In the case of having a base valve portion structure, it is preferable that the lower cap member 4 be a case member so that the base valve portion structure can be separated from the lower cap member 4.

  From the above, it is assumed that the air vent channel shown in FIG. 2 includes the perforation 24b that opens in the bottom portion 24 of the axle bracket 2, and the air vent channel shown in FIG. The screw 24c and the screw 4a of the lower cap member 4 are formed with a gap between the threads 24c. However, when the adhesive is injected, the air vent channel is formed at the rising portion 21 of the axle bracket 2. As long as air does not remain between the lower end portion 11 of the wheel side tube and the lower end portion 11 of the wheel side tube, for example, the lower cap member 4 may be formed with a perforated hole.

  In the above description, the case where the wheel side tube 1 constituting the fork main body is made of a CFRP pipe has been described as an example. However, from the point of view of the present invention, when the axle bracket 2 is connected to the wheel side tube 1. As long as an adhesive material is used, the wheel side tube 1 may be made of a metal material instead of the CFRP pipe, and the action and effect of the present invention in that case are not different.

  As described above, the axle bracket 2 is made of a metal material. However, according to the intention of the present invention, the wheel side tube 2 and the axle bracket 2 are made of a resin material other than CFRP. Of course, the invention can be embodied.

It is a longitudinal cross-sectional view which partially cuts and shows the lower end side part of the front fork by this invention. It is a fragmentary longitudinal cross-sectional view which expands and shows the state by which the seal case is clamped between the lower end of a wheel side tube and the bottom part of an axle bracket. It is a figure which shows the arrangement | positioning state of the seal case by other embodiment similarly to FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Wheel side tube 2 Axle bracket 3 Seal case 4 Lower cap member 4a, 24c Screw which forms air vent flow path 5, 6, 7 Seal member 11 Lower end part 21 Rising part 24 Bottom part 24b Air vent flow path 31 Main part 32 Buttocks

Claims (5)

The lower end of the wheel side tube is placed on the lower end of the wheel side tube while using the adhesive while the lower end of the wheel side tube is present inside the rising portion formed in a cylindrical shape extending in the axial direction of the wheel side tube forming the fork body together with the vehicle body side tube In a front fork having an axle bracket connected in a fixed state and having a bottom portion that is formed continuously at the lower end of the rising portion and carries the lower end serving as the opening end of the wheel side tube, the wheel side tube A seal case is sandwiched between the bottom end of the axle bracket and the bottom portion of the axle bracket so that the outer periphery faces the inner periphery of the opening end of the wheel side tube. A sealing member that circulates closely is held, and the rising part of the axle bracket and the lower end part of the wheel side tube Front fork between is characterized by comprising communicating with the outside through an air vent channel. The seal case is formed in an annular shape, and the seal member is held on the outer periphery of the main body portion that is present inside the opening end portion of the wheel side tube, and the lower end outer peripheral portion of the main body portion is formed in a flange shape. The front fork according to claim 1, wherein the flange portion is sandwiched between a lower end of the wheel side tube and a bottom portion of the axle bracket. The front fork according to claim 1, wherein the air vent channel is formed in a bottom portion of the axle bracket. The front fork according to claim 1, wherein the air vent channel is formed between a bottom portion of the axle bracket and a lower cap member connected to the bottom portion. The front fork according to claim 1, wherein the wheel side tube is made of a carbon fiber reinforced plastic pipe.

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