JP4117143B2 - Head structure in damper - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a head portion structure in a damper, and more particularly, to an improvement in the head portion structure in a damper built in a shaft core portion of a front fork.
[0002]
[Prior art]
For example, as shown in FIG. 5, when the damper D built in the shaft core portion of the front fork is set upright, the cylinder body 11 constituting the damper D is an outer tube 1 serving as an axle side tube. The rod body 12 is erected on the shaft core portion of the inner tube 2 which is the vehicle body side tube, and is configured so that the lower end side of the cylinder body 11 can be inserted and retracted while constituting the damper D. Yes.
[0003]
Incidentally, a suspension spring 3 is arranged between a head portion (not shown) which is the upper end portion of the cylinder body 11 and the upper end side of the rod body 12, and the rod body 12 is urged by the urging force of the suspension spring 3. The damper D, that is, the front fork is extended so as to protrude from the cylinder body 11.
[0004]
By the way, in this damper D, as shown also in FIG. 6, the upper end opening (not shown) of the cylinder body 11 is sealed with a head member 13 that allows the rod body 12 to penetrate the shaft core portion. In addition, the metal 14 that is a bearing member that is in sliding contact with the outer periphery of the rod body 12 is held on the inner periphery of the head member 13.
[0005]
Therefore, according to the head portion structure having the head member 13, the rod body 12 comes into sliding contact with the head member 13 via the metal 14, and a predetermined slidability in the rod body 12 is ensured. Become.
[0006]
[Problems to be solved by the invention]
However, in the above-described conventional head portion structure, the head member 13 is formed by cutting a cold forged one and is screwed into the upper end opening of the cylinder body 11. May be pointed out that there is a bug.
[0007]
That is, first of all, it is necessary to form a female screw (not shown) for screwing the head member 13 on the inner periphery of the upper end of the cylinder body 11, but the strength at the portion where this female screw is formed is ensured. In order to do so, it is necessary to increase the wall thickness in advance at least in the portion where the female screw is formed.
[0008]
Next, on the outer peripheral side of the head member 13, it is necessary to form a male screw (not shown) for screwing it into a female screw formed on the inner periphery of the upper end of the cylinder body 11. In other words, it is necessary to form an annular groove or the like (not shown) for holding the metal 14 as a bearing member on the inner peripheral side.
[0009]
Therefore, it is necessary to increase the thickness of at least the portion where the male screw or the annular groove is formed in advance so as to ensure the strength at the portion where the male screw or the annular groove is formed.
[0010]
Further, the head member 13 has to be screwed to the inner periphery of the upper end of the cylinder body 11, and therefore, this screwing work requires time and labor.
[0011]
As a result, in the above-described conventional head portion structure in the damper, the weight of the cylinder body 11 and the head member 13 cannot be reduced. Therefore, the weight of the damper D or the front fork having the damper D can be reduced. There is a disadvantage that cannot be reduced.
[0012]
And since the process with respect to the cylinder body 11 and the head member 13 is required, time and an effort are required for an assembly operation, The reduction in production cost is inhibited and productivity falls.
[0013]
The present invention has been developed in view of the above-described circumstances, and the object of the present invention is to improve the productivity and the production cost as well as to ensure a predetermined slidability. Further, it is possible to provide a head portion structure in a damper which is optimal for reducing the weight and further reducing the weight and expecting to improve the versatility.
[0014]
[Means for solving the problems]
In order to achieve the above-described object, the configuration of the head structure in the damper according to the present invention is such that a head member having a bearing member is provided at the upper end opening of the cylinder body, and the piston is provided in the cylinder body via the piston and the bearing member. In a damper in which a rod is movably inserted and has a predetermined damping action when the piston rod moves in and out, a cylindrical press-fit portion formed by pressing a head member, and a press-fit portion extending downward from the press-fit portion A smaller-diameter cylindrical bearing holding portion, one or a plurality of holes or recesses provided in the circumferential direction in the press-fit portion, a trumpet type spring support extending upward from the press-fit portion, and a spring support constituted by a chamfer which is formed corresponding to the position of the hole or recess in the end periphery, marks on the holes or recesses in said hole or the recess after press fitting the press-fit portion in the inner periphery of the upper end portion of the cylinder body Caulked part of the cylinder body engaged to, and further characterized in that press-fitting the bearing member on the inner periphery of the bearing holding portion.
[0016]
In the above configuration, more specifically, it is preferable that the damper is applied to a front fork with a built-in damper.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments for solving the problems will be described below with reference to the drawings. Of these, FIGS. 3 and 4 show an embodiment corresponding to claims 1 and 2.
FIG. 1 shows an example in which a damper head portion structure according to the present invention is applied to a front fork of a motorcycle.
[0018]
In this front fork, a vehicle body side tube 2 is slidably fitted in an axle side tube 1, and a damper 17 is erected on the shaft core portion of the axle side tube to constitute an upright front fork. The damper 17 includes a cylinder body 11 and a piston rod 12 that is movably inserted into the cylinder body 11 via a piston 16 and a bearing member 14, and a damping valve (not shown) provided on the piston 16 when the piston rod 12 moves in and out. To generate a damping force.
[0019]
The piston rod 12 is coupled to the upper end portion of the vehicle body side tube 2, and a suspension spring 3 is interposed between the head member 15 and the upper side of the vehicle body side tube 2. The suspension spring 3 is always connected to the vehicle body side tube 2 and the piston rod. 12 is energized in the direction of elongation.
In the head portion structure in the damper according to the present invention, as shown in FIG. 1, the head member 15 is formed by press working, and the head member 15 is press-fitted into the inner periphery of the upper end of the cylinder body 11. Thus, the upper end opening of the cylinder body 11 is closed.
[0020]
At this time, the head member 15 has a press-fit portion 15a formed in a cylindrical shape and is press-fitted into the inner periphery of the upper end of the cylinder body 11. On the other hand, The bearing holding portion 15b has a smaller diameter than the portion 15a.
[0021]
And this bearing holding part 15b shall hold | maintain the metal 14 which is a bearing member which slidably contacts the outer periphery of the rod body 12 to the inner periphery by press-fit, and is a cylindrical shape smaller diameter than the cylindrical press-fit part 15a. Therefore, the outer periphery forms an appropriate interval S on the inner periphery of the cylinder body 11.
[0022]
Therefore, since the head member 15 according to the present invention is formed by pressing, the weight can be greatly reduced as compared with the case where the conventional head member 13 is formed by forging.
[0023]
Further, since the head member 15 according to the present invention has a required accuracy when it is formed by pressing, so-called post-processing for having the required accuracy is not required.
[0024]
By the way, in this head member 15, an opening 15c that forms an oil passage is formed, but this opening 15c is formed at the stage of a so-called base material before pressing, and in that sense, This is not due to post-processing.
[0025]
Even in the cylinder body 11 into which the head member 15 is press-fitted, it is not necessary to perform a process such as forming a female screw on the inner periphery of the upper end thereof. There is no need to secure the thickness.
[0026]
Therefore, in the head member 15 according to the present invention, the upper end opening of the cylinder body 11 can be closed only by press-fitting the press-fit portion 15a into the inner periphery of the upper end of the cylinder body 11.
[0027]
Further, to hold the metal 14 on the bearing holding portion 15b, it is only necessary to press-fit the metal 14 into the inner periphery of the bearing holding portion 15b, and an annular groove for distributing the metal 14 to the bearing holding portion 15b is previously provided. There is no need to form the rod body 12, and a predetermined sliding property of the rod body 12 with respect to the head member 15 can be ensured.
[0028]
As a result, when the head portion structure according to the present invention is used, the head portion of the damper D can be realized, and the weight can be reduced and the number of processes can be greatly reduced, and the assembly work can be simplified. become.
[0029]
In addition, when the head portion structure according to the present invention is used, so-called bending can be expected in the bearing holding portion 15b. Therefore, smooth sliding performance of the rod body 12 with respect to the head member 15 can be ensured. .
[0030]
That is, in the present invention, since the outer periphery of the bearing holding portion 15b forms an appropriate interval S on the inner periphery of the cylinder body 11, the bearing holding portion 15b can be bent by a certain amount.
[0031]
Therefore, in the case of this head portion structure, when the rod body 12 inclines with respect to the cylinder body 11 in an inclined state, the bearing holding portion 15b bends so as to follow the rod body 12 and the rod body 12 and the head member. It is possible to prevent the galling phenomenon from occurring between 15 and 15.
[0032]
From this, the avoidance of the galling phenomenon is effective when the damper D that embodies the head portion structure is built in the shaft core portion of the front fork.
[0033]
Further, the upper end of the head member 15 is formed in a flange shape with a trumpet shape that expands upward, and serves as a lower spring receiver 15 e that carries the lower end of the suspension spring 3. By adopting such a shape, there is an effect that the suspension spring 3 can be carried without attaching a separate suspension spring receiver, and a predetermined damper function can be exhibited, thereby facilitating processing.
[0034]
Next, a second embodiment of the present invention will be described. FIG. 2 shows a second embodiment of the present invention.
[0035]
As shown in FIG. 2, four holes 15d are provided along the circumferential direction of the cylindrical press-fitting portion 15a of the head member, and the head member 15 is press-fitted into the inner periphery of the upper end of the cylinder body. Crimp the upper end of the cylinder body so that it matches. A single hole or a plurality of holes may be provided. Moreover, you may provide a recessed part instead of this hole.
Other structures, functions, and effects are the same as those of the embodiment of FIG. 1, and the same members are denoted by the same reference numerals and will not be described in detail.
[0036]
According to the embodiment shown in FIG. 2, the head member and the cylinder body can be firmly coupled to each other by press-fitting only by press-fitting the head member and then crimping the upper end of the cylinder body. Can do.
[0037]
Further, as shown in FIGS. 3A and 3B, four chamfered portions a are formed at equal intervals on the outer periphery of the suspension spring receiving side end of the head member 15 at four locations. After the head member 15 is press-fitted into the cylinder body 11, the hole 15d provided in the cylindrical press-fit portion 15a of the head portion 15 is hidden by the cylinder body 11, and the exact position of the hole is unknown. For this reason, the part which clamps the head member 15 end part of the jig | tool 18 for press-fitting the head member 15 in the cylinder body 11 is made into the shape of the chamfering b which corresponds to this edge part shape.
[0038]
And the mark 19 is provided in the outer peripheral part of the jig | tool 18, and this mark 19 and the crimping position are matched. Therefore, just by inserting the outer periphery of the suspension spring receiving side end portion of the head member 15 into the caulking jig 18, the position of the hole can be determined by the mark 19, and the predetermined position can be caulked accurately and easily. There is an effect.
[0039]
As described above, the flat portion can be easily positioned. However, as shown in FIG. 4, the tool 20 when screwing the damper cylinder into the outer tube is also on the suspension spring receiving side in the same manner as the jig 18 at the time of press-fitting. If the shape can be fitted to the outer periphery of the end, it can be used as a detent.
[0040]
【The invention's effect】
As described above, in the invention of each claim, since the head member constituting the head portion structure is formed by press working, the weight is significantly larger than that of a head member formed by conventional forging. Mitigation is possible.
[0041]
Further, since the head member according to the present invention has a required accuracy when it is formed by pressing, so-called post-processing for having the required accuracy is not required.
[0042]
Even in the cylinder body into which the head member is press-fitted, there is no need for processing such as forming an internal thread on the inner periphery of the upper end, and therefore the cylinder body is secured with consideration for screw processing. There is no need to keep it.
[0043]
Therefore, in the head member according to the present invention, the upper end opening of the cylinder body can be closed only by press-fitting the press-fit portion into the inner periphery of the upper end of the cylinder body. It is only necessary to press-fit the metal into the inner periphery of the bearing holding portion, and it is not necessary to previously form an annular groove for distributing the metal in the bearing holding portion. The predetermined slidability with respect to the member can be ensured.
[0044]
As a result, when the head part structure according to the present invention is used, the weight of the head part can be reduced and the number of processes can be greatly reduced in the implementation of the head part in the damper, and the assembly work can be simplified. Become.
[0045]
In addition, when the head portion structure according to the present invention is used, the outer periphery of the bearing holding portion faces the inner periphery of the cylinder body with an appropriate interval. Therefore, when the rod body inclines with respect to the cylinder body in an inclined state, the bearing holding portion bends to follow the cylinder body, and a galling phenomenon is prevented between the rod body and the head member. Will be able to.
[0046]
The avoidance of the galling phenomenon is effective when a damper that embodies the head structure according to the present invention is built in the shaft core portion of the front fork.
[0047]
As a result, according to the present invention, it is possible to assure predetermined slidability, as well as improve productivity, reduce production costs, and further reduce weight, It is most suitable for expecting the improvement of the versatility.
[0048]
Further, according to the first aspect of the present invention, a recess or hole provided in the circumferential direction in the cylindrical press-fit portion, engages in the recess or hole sites that conforms to the recess or hole of the cylinder body caulked by causing engagement may be capable of being firmly bonded to the head member and the cylinder body than the binding by press fitting only.
Moreover, chamfered end outer periphery of the spring receiver in response to the position of the hole or recess, for crimping a portion of the cylinder body with respect to the position of this chamfered, accurately and easily, place Can be tightened .
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a head part structure in a damper according to the present invention partially enlarged.
FIG. 2 is a cross-sectional view showing a partially enlarged head part structure in a damper according to a second aspect of the present invention;
FIG. 3A is a cross-sectional view of the head member on the spring receiving side inserted into a caulking jig.
(B) It is a Q direction arrow directional view of a caulking jig.
FIG. 4 is a cross-sectional view when a spring receiving side end of a head member is inserted into a caulking jig and a cylinder is screwed into an outer tube.
FIG. 5 is a schematic front view showing a partially built-in front fork for a damper as a conventional example.
FIG. 6 is a view showing a head structure in a conventional damper in the same manner as in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 Cylinder body 12 Rod body 14 Metal 15 which is a bearing member Head member 15a Hole 1 Outer tube which is an axle side tube 2 Inner tube which is a body side tube 3 Suspension spring D Damper S Gap

Claims (2)

In a damper in which a head member having a bearing member is provided in an upper end opening of a cylinder body, a piston rod is movably inserted into the cylinder body via the piston and the bearing member, and performs a predetermined damping action when the piston rod is retracted A cylindrical press-fit portion formed by pressing the head member; a cylindrical bearing holding portion extending downward from the press-fit portion and having a smaller diameter than the press-fit portion; and provided in the press-fit portion along the circumferential direction One or a plurality of holes or recesses, a trumpet type spring receiver extending upward from the press-fit portion, and a chamfer formed on the outer periphery of the end of the spring receiver corresponding to the position of the hole or recess. Then, after press-fitting the press-fitting portion into the inner periphery of the upper end portion of the cylinder body, a part of the cylinder body that matches the hole or the concave portion is caulked and engaged in the hole or the concave portion. Bearing member on the inner circumference Head structure in the damper, characterized in that off to.   The head part structure in a damper according to claim 1, wherein the damper is applied to a damper-equipped front fork.

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