JP4198579B2 - Front fork connection structure - Google Patents

Description

The present invention relates to a connection structure, and more particularly, to an improvement in a connection structure in a front fork when an opening end on a lower side of a wheel side tube in a front fork is connected in a state of being inserted into a recess of an axle bracket .

  For example, the lower end of the front fork mounted on the front wheel side of the two-wheeled vehicle is connected to the axle of the front wheel of the two-wheeled vehicle via an axle bracket. At this time, the lower end of the wheel-side tube that is a cylinder constituting the front fork The parts are connected to each other under a connecting structure inserted into an axle bracket that is a connected member.

  For example, in the connection structure disclosed in Patent Document 1, the lower end portion of the wheel-side tube is inserted and connected under the state of being screwed into the axle bracket.

Therefore, the front fork can be mounted on the front wheel side of the two-wheeled vehicle by connecting the axle bracket fixed to the lower end of the wheel-side tube to the front wheel axle of the two-wheeled vehicle.
Japanese Utility Model Publication No. 8-8361 (drawing)

  However, in the connection structure disclosed in Patent Document 1 described above, when the lower end portion of the wheel side tube is connected to the axle bracket, a male thread is formed on the outer periphery of the lower end portion of the wheel side tube. It is essential to form a female thread in the bracket for screwing the male thread.

  Therefore, in the connection structure described above, it is necessary to form male threads on the wheel side tube and female threads on the axle bracket. A problem that requires a screwing operation according to the length of the formed thread is pointed out.

  Not only at the lower end portion of the wheel side tube, but also at the lower end portion of the wheel side tube so that a predetermined mechanical strength can be ensured even if this thread is formed, by forming the thread at the lower end portion of the wheel side tube. The wall thickness must be made thicker than the other parts, and this reduces the weight reduction of the front fork.

The present invention, which has been developed in view of such circumstances, optimal and it is an object to allow a reduction in production costs, to expect an improvement in versatility in CFCs FORK It is providing the connection structure in the front fork which becomes.

In order to achieve the above-described object, the invention according to claim 1 is characterized in that the upper end side of the wheel side tube is inserted into the lower end side of the vehicle body side tube so that it can protrude and retract, and the wheel side tube is inserted from the vehicle body side tube by the suspension spring. In the connecting structure of the front fork, which is urged in the extending direction so as to protrude and the opening end on the lower side of the wheel side tube is inserted into the recess of the axle bracket and connected, a female thread is formed on the inner peripheral side An internal thread member comprising a cylindrical rising portion and a flange portion that extends horizontally from the base end of the cylindrical rising portion to the outer peripheral side and carries the lower end of the suspension spring is provided, and the outer peripheral end of the flange portion The bolt is fixed to the inside of the opening end of the wheel side tube by caulking, and a fastening bolt that penetrates in the axial direction of the axle bracket is screwed to the cylindrical rising portion. It was characterized by comprising.

  In this case, an annular receding portion or an annular groove may be formed inside the opening end portion of the wheel side tube in order to perform the caulking process with the outer peripheral side end portion of the flange portion being present.
Further, a spacer member may be disposed between the end of the wheel side tube and the bottom of the recess in the axle bracket to which the wheel side tube faces.

Therefore, in the invention of each claim , the lower end portion of the wheel side tube is fixed to the recessed portion of the axle bracket by screwing the tightening bolt, so that the outer periphery of the end portion of the wheel side tube is fixed. It is not necessary to form a male thread on the inner side of the shaft bracket , and it is not necessary to form a female thread on which the male thread is engaged inside the recess in the axle bracket .

Therefore, the lower end of the wheel side tube is fixed to the recessed portion of the axle bracket in a fixed state, that is, when assembling is performed, a screwing operation corresponding to the length of the formed thread is performed. It is not necessary, and the work can be simplified.

Then, do not form an external thread on the outer periphery of the wheel side tube, as long as having the required mechanical strength, becomes a wheel side tube can be made thinner, lighter weight in that amount, the front fork In addition, since no male thread is formed on the wheel side tube , there is no need to form a female thread on the axle bracket . Therefore, the cost of parts in the wheel side tube and the axle bracket is increased. Will get around.

As a result, according to the present invention, thereby enabling reduction in production cost and best to expect an improvement in versatility in CFCs FORK.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In the basic form of the present invention, the upper end side of the wheel side tube 1 is inserted into the lower end side of the vehicle body side tube so as to be able to protrude and retract, and the suspension tube S protrudes from the vehicle body side tube by the suspension spring S. This is related to a connecting structure in a front fork in which a lower opening end of the wheel side tube 1 is inserted into a recess of the axle bracket 2 and connected.
And in this invention, the cylindrical rising part 3b which formed the internal thread 3a in the inner peripheral side, and it is extended horizontally from the base end of this cylindrical rising part 3b to the outer peripheral side, and the lower end of the said suspension spring S is attached. A female screw member 3 including a supporting flange portion 3c is provided, and the outer peripheral side end portion of the flange portion 3c is fixed to the inner side of the opening end portion of the wheel side tube 1 by caulking, and the cylindrical rising portion 3b is fixed. A fastening bolt 4 penetrating in the axial direction of the axle bracket 2 is screwed together.

Although the front fork of the present invention is not shown in detail, the front fork is set upside down in the figure, and the upper end side of the wheel side tube 1 is located in the lower end side of the vehicle body side tube connected to the handle side of the two-wheeled vehicle. It is inserted so as to be able to appear and retract, and is urged by the suspension spring S in the extending direction in which the wheel side tube 1 protrudes from the vehicle body side tube.

  By the way, the connection structure by this invention inserted the edge part of the axial direction in the wheel side tube 1, ie, the lower opening end part 1a in the wheel side tube 1, into the recessed part 2a of the axle bracket 2 in the figure. It is said to be embodied when connecting to the state.

  In this connection structure, the shaft core portion of the axle bracket 2 is penetrated in the axial direction of the axle bracket 2 through the female screw member 3 held in a fixed state inside the opening end portion 1 a of the wheel side tube 1. It is assumed that the tightening bolt 4 to be screwed together.

  At this time, as shown in FIG. 1, the female screw member 3 has a cylindrical rising portion 3b for forming a female thread 3a on the inner peripheral side, and the outer peripheral side from the base end of the cylindrical rising portion 3b. It has a flange portion 3c extending horizontally.

  In the female screw member 3, the outer peripheral end of the flange portion 3 c is fixed to the inner peripheral side of the opening end 1 a of the wheel side tube 1 by caulking to the inner side of the opening end of the wheel side tube 1. It is supposed to be done.

  At this time, before the opening end of the wheel side tube 1 is bent inward and crimped, an annular receding portion 1b is formed inside the opening end portion 1a of the wheel side tube 1, and the annular receding portion 1b The outer peripheral side end of the flange portion 3c is present, and the crimping process is practiced in this state.

  Incidentally, the annular receding portion 1b, as shown in the figure, can be easily crimped by being thinner than the thickness of the so-called main body portion above the opening end portion 1a of the wheel side tube 1. It is also assumed that the inner periphery of the opening end 1a is formed so as to retreat. However, from the viewpoint of the function of the annular retreating portion 1b, the opening is not shown. It may be formed of an annular groove formed in the inner periphery of the end 1a.

  In addition, although said flange part 3c is formed in cyclic | annular form and carries the lower end of the above-mentioned suspension spring S after a heel, although not shown in figure at this time, the upper end of the flange part 3c and the lower end of suspension spring S A spring sheet for preventing the rotational force from the suspension spring S from directly acting on the flange portion 3c may be interposed between the spring seats.

  Therefore, in the place shown in FIG. 1, the female screw member 3 is fixedly fixed inside the opening end 1 a of the wheel-side tube 1, and therefore, the female screw member 3 is fastened to the female screw member 3. Even when the bolts 4 are screwed together, the female screw member 3 can be prevented from rotating in the accompanying movement state.

  On the other hand, the tightening bolt 4 passes through the shaft core portion of the axle bracket 2, that is, the shaft core portion in the thick portion 2 c forming the inner bottom 2 b of the recess 2 a in the axle bracket 2 in the axial direction of the axle bracket 2. Therefore, at the time of final tightening, which will be described later, the screwing operation portion 4a that is the head of the tightening bolt 4 is locked to the thick portion 2c.

  Then, as the tightening bolt 4 is screwed into the female screw member 3, the lower end of the wheel side tube 1 for fixing the female screw member 3 to the opening end 1a is set in the recess 2a of the axle bracket 2. When pressed against the bottom 2b and screwed until it cannot rotate, that is, at the time of final tightening, the integration of the wheel side tube 1 and the axle bracket 2 is realized.

  Incidentally, a seal member 5 is disposed between the axle bracket 2 and the wheel side tube 1, and a seal is provided between the screwing operation portion 4 a as the head of the fastening bolt 4 and the thick portion 2 c in the axle bracket 2. A copper packing 6 that functions as a member is disposed.

  In view of the above, in the connection structure according to the present invention, the opening end 1a of the wheel side tube 1 is fixed to the recessed portion 2a of the axle bracket 2 by the screwing of the tightening bolt 4, so that the opening in the wheel side tube 1 is fixed. It is not necessary to form a male thread on the outer periphery on the end 1a side, and it is not necessary to form a female thread into which the male thread is engaged inside the recess 2a in the axle bracket 2.

  Therefore, it is not necessary to perform a screwing operation according to the length of the formed screw at the time of assembling work for fixing the opening end 1a of the wheel side tube 1 to the recessed portion 2a of the axle bracket 2 in a fixed state. Therefore, the work can be simplified.

  Since no male thread is formed on the outer periphery of the wheel-side tube 1, it can be formed thin as long as it has a predetermined mechanical strength, which reduces the weight of the front fork. This contributes to the fact that no male thread is formed on the wheel-side tube 1, so there is no need to form a female thread on the axle bracket 2, and therefore the cost of parts in the wheel-side tube 1 and the axle bracket 2 is increased. It can be avoided.

Next, a reference example in which the shape of the female screw member 3 of claim 1 is changed will be described with reference to FIGS.

  That is, FIG. 2 shows that the female screw member 3 is formed in a so-called thick structure, and the female screw member 3 is formed in a thick structure in this way, so that the female screw member 3 on the inner peripheral side is formed. As a matter of course, the formation of the thread 3a can be easily ensured, but when the internal thread member 3 is held inside the opening end 1a of the wheel side tube 1 in a fixed state, compared with the place shown in FIG. Since the contact area between the two can be increased, the fixability can be improved accordingly.

  In addition, as shown in the figure, the female screw member 3 has a male thread 3d on the outer periphery, and the male thread 3d is formed on the inner periphery of the opening end 1a of the wheel side tube 1. Since it is supposed to be screwed to the strip 1c, it is possible to greatly improve the integrity with the wheel side tube 1.

  Incidentally, the screw 1c described above is formed in the annular receding portion 1b as shown in the figure, but instead, it is not shown in the annular groove or at the open end. It may be formed directly on the inner circumference of 1a.

In the reference example shown in FIG. 2, in the case where the weight of the part in the female screw member 3 is reduced, as long as a predetermined mechanical strength can be ensured, as shown by a broken line in the figure, an annular shape is used. It is preferable to form the empty portion 3e.

  Next, as shown in FIG. 3, an annular spacer member 7 is disposed between the end portion in the axial direction of the wheel side tube 1 and the inner bottom 2 b of the concave portion 2 a in the axle bracket 2 facing this. Suppose that

  At this time, the spacer member 7 is illustrated as having an annular hollow portion 7a having a downwardly concave cross section so as to reduce the weight of the component. Of course, it may be formed so-called innocent without the portion 7a.

  At this time, the spacer member 7 is arranged so as to drop onto the inner bottom 2b of the recess 2a, and is not connected to the lower end of the wheel side tube 1 as well as the axle bracket 2. Instead of this, although not shown, of course, it may be integrally or integrally connected to the lower end of the wheel-side tube 1 or the upper female screw member 3, and in this case, This is advantageous in that the spacer member 7 can be reliably fixed at a predetermined position.

Incidentally, in this reference example , the female screw member 3 is formed in a thick-walled structure as in the case shown in FIG. 2, but the outer periphery is within the opening end portion 1 a of the wheel side tube 1. It is assumed that fixing is performed by caulking to the inside of the opening end of the wheel-side tube 1 in a state of being present in the annular receding portion 1b formed on the circumference.

Therefore, in this reference example , by selecting the thickness of the spacer member 7, the spring force of the suspension spring S whose lower end is locked to the female screw member 3 can be adjusted in height.

It is a partial semi-longitudinal longitudinal cross-sectional view which shows the lower end part of the front fork which embodied the connection structure by one Embodiment of this invention. It is a figure which shows the connection structure by a reference example similarly to FIG. Furthermore, it is a figure which shows the connection structure by another reference example similarly to FIG.

Explanation of symbols

1 Wheel side tube 1a Open end
1b annular receding part 2 axle bracket 2a recess 2b inner bottom 3 female screw member
3a female thread
3b cylindrical riser
3c Flange 4 Clamping bolt 7 Spacer member S Suspension spring

Claims (3)

The upper end side of the wheel side tube is removably inserted into the lower end side of the vehicle body side tube, and the wheel side tube is urged by the suspension spring so that the wheel side tube protrudes from the vehicle body side tube. In the connecting structure of the front fork in which the opening end on the lower side is inserted into the recess of the axle bracket and connected, a cylindrical rising part having a female thread formed on the inner peripheral side, and an outer periphery from the base end of the cylindrical rising part An internal thread member is provided that includes a flange portion that extends horizontally to the side and carries the lower end of the suspension spring, and the outer peripheral side end portion of the flange portion is crimped to the inside of the opening end portion of the wheel side tube. put it together to fix it becomes by screwing the fastening bolt extending in the axial line direction of the axle bracket to the cylindrical rising portion to the front fork, wherein Consolidated structure. The connecting structure for a front fork according to claim 1 , wherein an annular receding portion or an annular concave groove is formed inside the opening end portion of the wheel side tube in order to perform the caulking process with the outer peripheral side end portion of the flange portion being present . The connection structure in the front fork according to claim 1 , wherein a spacer member is disposed between the end of the wheel side tube and the bottom of the recess in the axle bracket to which the wheel side tube faces .

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