JP3650848B2 - Fork member for shock absorber support - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a shock absorber supporting fork member (hereinafter referred to as a “fork member”) for connecting a shock absorber constituting a vehicle suspension device to a lower link member, and more specifically, a holder for gripping the lower end of the shock absorber. It relates to the structure of the part.
[0002]
[Prior art]
As shown in FIG. 5, the suspension device includes a strut member including a shock absorber 21, which connects the lower link member 40 and the compression rod 50 to the wheel support 30, and connects the upper link member 70 via the knuckle steering 60. 20 is connected to the lower link member 30.
The strut member 20 includes a shock absorber 21, a coiled spring member 22 provided on the shock absorber 21, and a fork member 10 that connects the shock absorber 21 and the lower link member 30.
The fork member 10 employed in the suspension device is a known member for connecting the shock absorber 21 to the lower link member 40, and includes an arm portion 13, a holder 14, and a pin connecting portion 15.
In the above-described configuration, the arm portion 13 is a member that transmits a load and an external force from the lower link member 40 side to the shock absorber 21, and has a resistance against the transmitted load and the external force. The pin connecting portion 15 is a part formed integrally with the lower end of the arm portion 13, and connects the lower end of the arm portion 13 holding the shock absorber 21 to the lower link member 40. The holder 14 is a part formed integrally with the upper end of the arm portion 13, and has a receiving portion that can hold and hold the lower end of the shock absorber 21. It is a member that holds the lower end of the absorber 21.
As a means for gripping the shock absorber 21 of the holder 14, for example, a known clamp having a C-shaped cross section is employed. The shock absorber 21 is gripped by using the gripping force generated by accommodating the lower end of the shock absorber 21 in the accommodating portion of the clamp and fastening the open end of the accommodating portion with a known fastening means such as a bolt. ing.
At this time, since the gripping force of the shock absorber 21 is determined by the fastening force of the bolt for fastening the clamp, a high tension bolt that enables a high tension setting to obtain a gripping force sufficient to prevent the shock absorber 21 from coming off. Etc. are used.
[0003]
[Problems to be solved by the invention]
The fork member holder structure described above has the following problems.
That is, the holder of the conventional fork member has a smooth inner surface in the housing portion, and therefore, the open end of the housing portion is fastened with a high tension bolt so that the entire inner circumference surface can be gripped uniformly. A high fastening force was required to grip the shock absorber, such as exerting force.
[0004]
The present invention has been made in view of the above problems, does not require a high fastening force by a bolt, can securely grip a shock absorber, and can achieve weight reduction and cost reduction by saving material. It is an object to provide a fork member for supporting a shock absorber.
The object is to increase the gripping force of the shock absorber by the fork member holder and prevent the shock absorber from coming out with a simple structure.
The present invention provides a fork member for supporting a shock absorber, which aims to achieve at least one of the above objects.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, a fork member for supporting a shock absorber according to the present invention is a member constituting a suspension device, and is formed integrally with an arc-shaped arm portion and an upper end of the arm portion. And a holder having a C-shaped cross section that can receive the lower end of the shock absorber that has been painted and can be clamped by bolt fastening, and a pin connecting portion that is provided at the lower end of the arm portion and includes a connecting pin with the lower link member; The fork member for supporting a shock absorber is formed such that the shape of the joint surface between the arm portion and the holder has a thickness difference between the upper portion and the lower portion of the holder, and the inner peripheral surface of the holder is defined as Ra. It is formed on 3 to 10 rough surfaces.
[0006]
In the shock absorber supporting fork member described above, the rough surface in the holder is formed as a groove along the circumferential direction.
[0007]
In the fork member for supporting the shock absorber described above, the rough surface is formed so as to have a mountain-shaped cross section.
[0008]
Further, in the shock absorber supporting fork member described above, the rough surface is an inclined surface in a direction that gently intersects the lower end axis direction of the shock absorber accommodated in the holder, and the holder lower side is substantially perpendicular. It is formed so as to have a sawtooth cross-sectional shape with a substantially right-angled surface.
[0009]
Further, in the fork member for supporting the shock absorber, the formation pitch of the rough surface is made non-uniform.
[0010]
In any of the above-described shock absorber supporting fork members, the shape of the joint surface between the arm part and the holder may be formed so as to have a thickness difference between the upper part and the lower part of the holder. .
[0011]
According to the fork member for supporting a shock absorber of the present invention configured as described above, it is possible to obtain a sufficient gripping force for gripping the shock absorber without introducing an excessive fastening force. Therefore, it is not necessary to introduce high tension when fastening the bolt, and the risk of damaging the bolt can be avoided.
[0012]
Further, since the above-described configuration does not give an unnecessarily high design strength, the amount of material required for the entire fork member including the holder can be reduced, and the weight and cost can be reduced.
[0013]
DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1
Hereinafter, an embodiment of a fork member for supporting a shock absorber (hereinafter referred to as “fork member”) according to the present invention will be described in detail with reference to FIGS. Functional parts and parts will be described with the same reference numerals.
The fork member 10 has an arm portion 13 having an arc shape having a substantially triangular shape in cross section with the inner peripheral side 12 being thicker than the outer peripheral side 11, and a joint shape at the upper end of the arm portion 13 as a substantially triangular cross section. The holder 14 is formed on the lower end of the arm portion 13 and the pin connecting portion 15 is formed integrally with the lower end of the arm portion 13.
Hereinafter, the holder 14 that holds the shock absorber will be described.
[0014]
<A> Holder Structure For the holder 14 of the fork member 10, known gripping means such as a clamp having a C-shaped cross section as shown in FIG.
The holder 14 has a vertical accommodating portion 141 that can accommodate the lower end of the shock absorber 21. The accommodating portion 141 has an opening 142 in the vertical direction, and the inner diameter of the accommodating portion 141 can be reduced by narrowing the opening 142.
Bolt holes 143 and 143 are formed on the same line at both ends forming the opening 142 of the holder 14. The inner diameter of the accommodating portion 141 can be reduced by inserting a bolt 144 from one of the holders 14 into the bolt holes 143 and 143 and screwing them in. It should be noted that the drilling position of the bolt hole 143 is set substantially at the center of the holder 14 and is set so that a uniform fastening force is generated in the holder lower part 145 and the holder upper part 146 when fastening with the bolt 144.
[0015]
<B> Accommodating part In the structure of the holder 14 described above, the accommodating part 141 can increase the gripping force by forming a rough surface on its inner peripheral surface and increasing the frictional resistance in the pull-out direction of the lower end of the shock absorber 21. it can.
Specifically, as shown in FIG. 3, a plurality of protrusions 148 are formed as rough surfaces on the inner peripheral surface of the accommodating portion 141. The protrusion 148 can be formed in an annular shape in the direction perpendicular to the axis of the accommodating portion 141, for example. At this time, the rough surface may be formed by arranging a plurality of protrusions 148 that are independent of each other in a single line, or may be formed as a ring that has a spiral shape in which a large number of protrusions 148 are connected in series. Also good.
[0016]
Furthermore, the roughness of the rough surface is a minimum value in consideration of the thickness of the paint film layer 211 for the purpose of rust prevention or the like applied to the lower end of the shock absorber 21 in order to ensure sufficient gripping force. the surface roughness of the formed in Ra3, in consideration of workability to be described later, to form a maximum value Ra 1 0. That is, the roughness range of the rough surface is preferably Ra3-10 . Specifically, considering that the coating film thickness of the coating usually applied to the outer periphery of the shock absorber 21 is 12 μm on average, in order to prevent premature slippage due to external force, at least this coating film thickness is exceeded. Ra3 is required even for the minimum value as the large roughness (projection 148 height) H. Further, considering the workability of the inner peripheral surface of the holder 14, the maximum value of the roughness range is Ra10 . If Ra15 exceeds Ra10 in the roughness range, the load on cutting is large, the bite (the blade for rough surface formation) is greatly damaged, and the mechanical capacity is excessive. A malfunction occurs. Further, when the load of the cutting tool is increased, vibration is generated, and there is a risk that stable rough surface forming may be impossible due to the vibration. Furthermore, since the feed of the cutting tool is relatively increased with respect to the cutting rotation, the processing method becomes complicated and inefficient. As a specific shape of the plurality of protrusions 148 constituting the rough surface, for example, the cross section of the protrusion 148 is symmetrical with the inclined surface facing the holder upper portion 146 opening side and the inclined surface facing the holder lower portion 145 opening side. You may form in the cross-sectional mountain shape which becomes. Of course, the protrusion 148 is not limited to this, and other known cross-sectional shapes that can exhibit high frictional resistance can be adopted.
[0017]
<C> Joining surface 147 of the holder and the arm part The joining surface 147 of the holder 14 and the arm part 13 has the outer peripheral side (thin wall side) 11 positioned at the upper part of the holder 14 and the inner peripheral side (thick side) 12 at the lower part. Presents a substantially triangular shape where is located. At this time, when the bolt 144 is tightened, a uniform fastening force is applied to the holder lower part 145 and the holder upper part 146, but of the joint surface 147 between the holder 14 and the arm portion 13, an opening is made from the joint surface 147 a on the upper side of the holder 14. 142 is larger than the length from the joint surface 147 b on the lower side of the holder 14 to the opening 142, the difference between the rigidity of the holder lower portion 145 and the holder upper portion 146 occurs, and the holder lower than the deformation amount of the holder lower portion 145. The deformation amount of the upper part 146 becomes relatively large.
Therefore, the holder upper opening after fastening is narrower than the lower opening. As a result, the holder upper portion 146 can ensure a larger gripping force than the holder lower portion 145, and the wedge action acts on the shock absorber 21 gripped thereby, thereby improving the slip-out preventing function.
[0018]
<D> Operation of the holder With the structure of the holder 14 described above, the frictional resistance obtained by forming a rough surface on the inner peripheral surface of the accommodating portion 141 of the holder 14 and the inner diameter of the accommodating portion 141 by fastening the bolt 144 are reduced. The fastening force to make the diameter and the obtained gripping force of the shock absorber 21 are higher than the case where the inner peripheral surface of the holder is a smooth surface. Further, in addition to the frictional resistance obtained by the rough surface molding on the inner peripheral surface of the housing portion 141 of the holder 14 and the fastening force due to the inner diameter reduction of the housing portion 141 by fastening the bolt 144, the holder 14 and the arm portion 13 By cooperating the wedge action due to the thickness difference of the joint surface 147, it is possible to prevent the shock absorber 21 from coming out higher. Further, in this embodiment, an example in which the thickness difference between the holder lower portion 145 and the holder upper portion 146 is provided for the joint surface 147 between the arm portion 13 of the fork member 10 and the holder 14 is not limited thereto. Of course, even in the case of the same wall thickness, a higher gripping force can be obtained by the rough surface of the inner peripheral surface of the holder 14 described above.
[0019]
Second Embodiment of the Invention
Next, a second embodiment of the present invention will be described.
As the protruding cross-sectional shape constituting the rough surface in the present embodiment, a sawtooth shape is used as shown in FIG. 4 instead of the mountain shape described in the first embodiment of the invention.
[0020]
That is, the cross-section of the projection 148 that is a rough surface formed on the inner peripheral surface of the accommodating portion 141 of the holder 14 is a gentle inclined surface 148a with respect to the lower end axial direction of the shock absorber 21 on the holder upper portion 146 opening side. A sawtooth shape is formed by forming a substantially right-angle inclined surface 148b in a substantially orthogonal direction on the opening side of the holder lower portion 145.
Accordingly, when the lower end portion of the shock absorber 21 is inserted into the accommodating portion 141 of the holder 14, since the insertion is performed in the direction from the holder upper portion 146 to the holder lower portion 145, the inclination of the inclined surface 148 a of each protrusion 148 is less than a right angle. Therefore, the saw-tooth shape functions as a guide and can be inserted with a relatively low frictional resistance.
[0021]
On the other hand, in the pulling-out direction of the shock absorber 21 from the holder lower part 145 toward the holder upper part 146, a force is applied in the direction of the substantially right-angled slope 148b, so that each substantially right-angled slope 147b opposes the pulling-out direction of the lower end. Since the contact is made at a substantially right angle in this example, the frictional resistance is increased by being located on the shock absorber 21, and the lower end of the shock absorber 21 is prevented from being pulled out of the housing portion 141.
[0022]
In the second embodiment of the present invention, as in the first embodiment of the present invention, the frictional resistance obtained by making the cross-section of the protrusion 148 constituting the rough surface into a sawtooth shape and the bolt 144 are fastened. In addition to the fastening force due to the inner diameter reduction of the accommodating portion 141, the shock absorber 21 can be prevented from coming off in cooperation with the wedge action due to the thickness difference of the joint surface 147 between the holder 14 and the arm portion 13.
[0023]
Embodiment 3 of the Invention
Next, a third embodiment of the present invention will be described.
In this embodiment, in addition to the first and second embodiments described above, the pitch of the rough surface (pitch between protrusions) on the holder lower side 145 and the holder upper side 146 of the inner peripheral surface of the holder 14 of the shock absorber 21 is as follows. Is changed unevenly. For example, the upper half rough surface pitch of the holder inner peripheral surface is formed to be relatively larger than the lower half rough surface pitch. This provides the following advantages.
[0024]
That is, in this embodiment, when the wedge action due to the thickness difference of the joint surface 147 between the holder 14 and the arm portion 13 is used as in the first embodiment of the invention, the wedge action is not expected below the holder inner peripheral surface. By changing the rough surface pitch with respect to the half, the frictional resistance can be made larger than that of the upper half of the inner peripheral surface of the holder, and the effect of preventing the shock absorber 21 from coming out can be made more remarkable. Specifically, an example is to set the pitch of the rough surface to be smaller (finer) below than above.
Thereby, a high gripping force is obtained by a synergistic effect with the wedge action due to the wall thickness difference of the holder 14, and the shock absorber 21 can be prevented from coming out.
The above-mentioned pitch may change the size of the rough surface pitch from an arbitrary position on the inner peripheral surface of the holder, or the rough surface pitch gradually decreases (finely) from the upper side to the lower side of the holder inner peripheral surface. You may do it.
[0025]
【The invention's effect】
Since the present invention has been described above, the following effects can be obtained.
[0026]
<B> According to the fork member for supporting a shock absorber of the present invention configured as described above, the inner peripheral surface of the accommodating portion of the shock absorber is formed into a rough surface, and the pitch of the rough surface is made uneven. Thus, it is possible to obtain a sufficient gripping force without introducing an excessive fastening force for gripping the shock absorber. Therefore, it is not necessary to introduce high tension when fastening the bolt, and the risk of damaging the bolt can be avoided.
[0027]
<B> According to the shock absorber supporting fork member of the present invention configured as described above, the shock absorber can be sufficiently gripped by a configuration normally required for a holder, and as described above, using a bolt. Since it is not necessary to introduce high tension at the time of fastening of the accommodating portion, it is not necessary to separately give strength to the entire fork member including the holder, so that weight saving and cost reduction by material saving can be realized.
[0028]
<C> According to the shock absorber supporting fork member of the present invention, the frictional resistance in the pulling direction obtained by the rough surface molding on the inner peripheral surface of the holder housing portion and the fastening force due to the inner diameter reduction of the housing portion by bolt fastening. Further, the wedge action due to the thickness difference between the joint surfaces of the holder and the arm portion cooperates to obtain a higher gripping force, thereby preventing the shock absorber from coming out.
[Brief description of the drawings]
1 is an explanatory view of a shock absorber supporting fork member including a holder according to Embodiment 1 of the present invention. FIG. 2 is an explanatory view of a holder according to Embodiment 1 of the present invention. FIG. 4 is a longitudinal sectional view of a holder according to a second embodiment of the present invention. FIG. 5 is a perspective view of a conventional suspension device.
DESCRIPTION OF SYMBOLS 10 Shock absorber support fork member 11 Outer peripheral side 12 Inner peripheral side 13 Arm part 14 Holder 141 Accommodating part 142 Opening 143 Bolt hole 144 Bolt 145 Holder lower part 146 Holder upper part 147 Joint surface 147a Upper joint face 147b Lower joint face 148 Projection 148a Inclined surface 148b Slightly inclined surface 15 Pin connecting member 20 Strut member 21 Shock absorber 22 Spring member 30 Wheel support 40 Lower link member 50 Compression rod 60 Knuckle steering 70 Upper link member

Claims (5)

C-shaped cross-section that is a member constituting a suspension device and is formed integrally with an arc-shaped arm part and an upper end of the arm part, and accommodates a lower end of a coated shock absorber and can be clamped by bolt fastening A shock absorber supporting fork member comprising a holder and a pin connecting portion provided at a lower end of the arm portion and having a connecting pin with a lower link member,
While forming the shape of the joint surface between the arm part and the holder so as to have a thickness difference between the upper part and the lower part of the holder,
The inner peripheral surface of the holder is formed as a rough surface of Ra 3 to 10,
Fork member for shock absorber support.     The fork member for shock absorber support according to claim 1, wherein the rough surface in the holder is a groove along a circumferential direction.     The shock absorber supporting fork member according to claim 1 or 2, wherein the rough surface has a mountain-shaped cross section.     The shock absorber supporting fork member according to claim 1 or 2, wherein the rough surface is an inclined surface in a direction gently intersecting the upper side of the holder with respect to the lower end axial direction of the shock absorber accommodated in the holder, A fork member for supporting a shock absorber, wherein the fork member has a sawtooth shape in section with the lower side being a substantially right angle surface in a substantially perpendicular direction.   The shock absorber supporting fork member according to any one of claims 1 to 4, wherein the rough surface has a non-uniform pitch.

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