JP2013199947A - Suspension device and method of machining outer tube of suspension device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a suspension device, and a method of machining an outer tube of the suspension device, configured to facilitate machining of the outer tube.SOLUTION: A suspension device has an outer tube 1 which is formed in a tubular shape, and includes thickness changed parts 1a, 1b where thicknesses of left and right parts 12, 13 are formed thinner than thicknesses of front and rear parts 10, 11. When the thickness change parts 1a, 1b are cut in a radial direction, an outer circumference 2 of the thickness changed parts is formed of front, rear, left and right circular arcs 20, 21, 22 and 23. Centers p1 of curvature of front and rear circular arcs are the same. Curvature radii r1, r2 of the front and rear circular arcs 20, 21 are formed to be equal to each other. Centers of curvature of the left and right circular arcs 22, 23 are shifted in a direction separating from the left and right circular arcs 22, 23 with respect to the centers p1 of curvature of the front and rear circular arcs 20, 21. The curvature radii r3, r4 of the left and right circular arcs 22, 23 are formed to be larger than the curvature radii r1, r2 of the front and rear circular arcs 20, 21.

Description

  The present invention relates to a suspension device and an improvement of a method for processing an outer tube of the suspension device.

  In general, in transportation equipment such as automobiles and motorcycles, a suspension device is interposed between a vehicle body and a wheel, and the suspension device suppresses an impact caused by road surface unevenness from being transmitted to the vehicle body.

  For example, a suspension device for suspending a front wheel in a straddle-type vehicle such as a motorcycle is called a front fork, and a pair of suspension device bodies that stand on both sides of the front wheel and rotatably support the front wheel, and the suspension A bracket for connecting the apparatus main body and a steering shaft attached to the bracket are provided.

  And the said steering shaft is rotatably attached to the head pipe of the flame | frame used as the frame | skeleton of a vehicle body. Further, since the steering shaft or the bracket has a handle fixed thereto, the direction of the front wheel can be changed by rotating the handle.

  The suspension device main body includes an outer tube and an inner tube inserted into the outer tube so as to be able to appear and retract. The suspension device main body includes a suspension spring that absorbs an impact caused by road surface unevenness, A shock absorber that suppresses the expansion and contraction motion accompanying the shock absorption is accommodated.

  In the suspension device disclosed in Patent Document 1, when the outer tube is cut in the radial direction, the inner periphery of the outer tube is formed into a perfect circle, and the outer periphery is long in the front-rear direction toward the traveling direction of the vehicle body. It is formed in an elliptical shape, and the thickness of the left and right portions of the outer tube is thinner than the thickness of the front and rear portions.

  For this reason, in the above suspension device, the thickness of the front and rear portions is increased in the traveling direction of the vehicle body to increase the rigidity against the force acting in the front and rear direction, and the thickness of the left and right portions is decreased to reduce the thickness of the suspension device. Weight can be reduced.

Kaikai hei 2-12543

  However, in the conventional front fork (suspension device), when the outer base tube is formed by cutting a cylindrical base material, it is difficult to form the outer periphery of the outer tube into an elliptical cross section, such as milling. The meat-cutting by was inefficient.

  Accordingly, an object of the present invention is to increase the rigidity with respect to a force acting in the front-rear direction toward the traveling direction of the vehicle body, reduce the weight, and easily and efficiently process the outer tube. It is to provide an outer tube processing method for an apparatus.

  The first means for solving the above problems is formed in a cylindrical shape, and the thickness of at least one of the left portion and the right portion is thinner than the thickness of the front and rear portions in the traveling direction of the vehicle body. In the suspension device including the outer tube having one or more thickness changing portions, the outer circumference of the thickness changing portion is formed of front, rear, left and right arcs, and the center of curvature of the front and rear arcs is the same, and The arcs of curvature of each of the arcs are formed equally, and the center of curvature of at least one of the left and right arcs deviates from the center of curvature of the preceding and following arcs away from at least one of the arcs of the left and right sides. In addition, the radius of curvature of at least one of the left and right arcs is larger than the curvature radius of the preceding and following arcs.

  The second means for solving the above-mentioned problem is an outer tube of a suspension device that is formed in a cylindrical shape, and an inner tube and an outer periphery are concentric circles and a base material that is a perfect circle is turned to form an outer tube. In the processing method, a first step of fixing the base material to a chuck eccentric with respect to a rotation center of a rotating body in a lathe, and cutting a part of an outer periphery of the base material away from the rotation center; The base material is rotated 180 degrees and fixed to the chuck set in the same manner as in the first step, and a part of the outer periphery located on the opposite side of the base material from the first step is shaved. Two steps.

  According to the present invention, it is possible to increase the rigidity with respect to a force acting in the front-rear direction toward the traveling direction of the vehicle body, reduce the weight, and to easily and efficiently process the outer tube. .

It is a left view which shows the outer tube of the suspension apparatus which concerns on one embodiment of this invention. It is a cross-sectional view which expands and shows the thickness change part in the outer tube of the suspension apparatus which concerns on one embodiment of this invention to radial direction. It is explanatory drawing which shows typically the 1st process for forming the outer tube of the suspension apparatus which concerns on one embodiment of this invention from a cylindrical preform | base_material by a lathe process, and the thickness change part is on the left side in FIG. The partial cross section of an outer tube is shown on the right side in FIG. It is explanatory drawing which shows typically the 2nd process for forming the outer tube of the suspension apparatus which concerns on one embodiment of this invention from a cylindrical preform | base_material by a lathe process, and the thickness change part is on the left side in FIG. Is shown, and a partial vertical cross section of the outer tube is shown on the right side in FIG.

  Hereinafter, a suspension device and a method for processing an outer tube of the suspension device according to an embodiment of the present invention will be described with reference to the drawings. The same reference numerals given throughout the several drawings indicate the same or corresponding parts.

  As shown in FIGS. 1 and 2, the suspension device according to the present embodiment is formed in a cylindrical shape, and the left and right parts 12 and 13 (the left part 12 and the right part 13) in the traveling direction of the vehicle body. The suspension device includes an outer tube 1 having two thickness changing portions 1a and 1b that are formed to be thinner than the thickness of the front and rear portions 10 and 11 (the front portion 10 and the rear portion 11).

  And as shown in FIG. 2, the outer periphery 2 of each said thickness change part 1a, 1b consists of front-back, right-and-left circular arcs 20, 21, 22, and 23, and the center of curvature of the front-back arcs 20 and 21 is the same at p1. And the radii of curvature r1 and r2 of the front and rear arcs 20 and 21 are equal (r1 = r2).

  Further, the center of curvature p2, p3 of the left and right arcs 22, 23 is shifted in a direction away from the left and right arcs 22, 23 with respect to the center of curvature p1 of the front and rear arcs 20, 21, and the left and right arcs 22 , 23 are formed to be larger than the radii of curvature r1, r2 of the front and rear arcs 20, 21 (r3, r4 <r1, r2).

  Hereinafter, in detail, the suspension device according to the present embodiment is a front fork that suspends the front wheel of a straddle-type vehicle such as a motorcycle. Since the structure of this front fork is well known, it is not shown in detail, but the front fork is a pair of suspension device bodies that stand up on both sides of the front wheel and rotatably support the front wheel, and a bracket that connects the suspension device body B (FIG. 1) and a steering shaft (not shown) attached to the bracket B are provided.

  Although not shown, the steering shaft is rotatably attached to a head pipe disposed on the front side in the traveling direction of a frame serving as a skeleton of the vehicle body.

  The bracket B includes an upper bracket B1 and an under bracket B2 that connect a pair of suspension device main bodies. Further, since a handle (not shown) is fixed to the upper bracket B1, the front wheel rotates together with the front fork by rotating this handle, and the straddle-type vehicle can be steered.

  Subsequently, each suspension device main body includes an outer tube 1 and an inner tube (not shown) that is inserted into the outer tube 1 so as to be able to appear and retract. The front fork (suspension device) of the present embodiment is an inverted front fork in which the outer tube 1 is connected to the vehicle body side via the bracket B, and an inner tube (not shown) is connected to the wheel side.

  As shown in FIG. 1, the outer tube 1 includes a first attachment portion 1c to which the upper bracket B1 is attached, a second attachment portion 1d to which the under bracket B2 is attached, and the attachment portions 1c and 1d. There are provided a first thickness changing portion 1a arranged in between, and a second thickness changing portion 1b arranged on the wheel side (lower side in FIG. 1) of the second mounting portion 1d.

  When the outer tube 1 is cut in the radial direction (perpendicular to the axial center line of the outer tube 1), the first and second mounting portions 1c and 1d are not shown, but the inner and outer circumferences are true. It is formed in a circular shape.

  In addition, when the outer tube 1 is cut in the radial direction, the first and second wall thickness changing portions 1a and 1b have an inner circumference 3 formed in a perfect circle as shown in FIG. The outer periphery 2 is composed of four arcs 20, 21, 22, and 23 on the front, rear, left, and right sides in the traveling direction of the vehicle body.

  In FIG. 2, a to d indicate the boundaries of the arcs 20, 21, 22, and 23, and the front arc 20 (range a to b) corresponds to the front portion 10 of the thickness changing portions 1a and 1b. The rear arc 21 (ranges c to d) is at a position corresponding to the rear portion 11 in the thickness changing portions 1a and 1b, and the left arc 22 (range d to a) is the thickness changing portion 1a, The right arc 23 (range b to c) is at a position corresponding to the right portion 13 of the thickness changing portions 1a and 1b.

  The centers of curvature of the front and rear arcs 21 and 22 are p1 and are at the same position. The center of curvature p1 is also the center of the inner periphery 3, and the front and rear arcs 20 and 21 are concentric with the inner periphery 3. Further, as described above, the radii of curvature r1 and r2 of the front and rear arcs 20 and 21 are equal and r1 = r2, and the front and rear arcs 21 and 22 are on the same circumference.

  Subsequently, the center of curvature p2 of the left arc 22 is on an extension of the line l1 connecting the center of curvature p1 of the front and rear arcs 20 and 21 and the middle point of the left arc 22, and the curvature of the front and rear arcs 20 and 21 is. It is located on the right side of the center p1. The distance between the center of curvature p1 of the front and rear arcs 20 and 21 and the center of curvature p2 of the left arc 22 is Δ1, and the radius of curvature r3 of the left arc 22 is the radius of curvature r1 and r2 of the front and rear arcs 20 and 21. And r3> r1 = r2.

  Further, the distance from the left arc 22 to the center of curvature p1 of the front and rear arcs 20 and 21 is set to be smaller than the curvature radii r1 and r2 of the front and rear arcs 20 and 21, and larger than the radius of the inner circumference 3. Therefore, the thickness of the left portion 12 in the thickness changing portions 1a and 1b is thinner than the thickness of the front and rear portions 10 and 11.

  Subsequently, the center of curvature p3 of the right arc 23 is on an extension of the line l2 connecting the center of curvature p1 of the front and rear arcs 20 and 21 and the middle point of the right arc 23, and the curvature of the front and rear arcs 20 and 21 is. It is located on the left side of the center p1. In this embodiment, the outer tube 1 is formed symmetrically, and the line l1 connecting the line l2 and the center of curvature p1 of the front and rear arcs 20 and 21 and the midpoint of the left arc 22 is the same. It is arranged on a straight line.

  The distance between the center of curvature p1 of the front and rear arcs 20 and 21 and the center of curvature p3 of the right arc 23 is Δ2, which is equal to Δ1 (Δ1 = Δ2). That is, the centers of curvature p2 and p3 of the left and right arcs 22 and 23 are arranged symmetrically about the center of curvature p1 of the front and rear arcs 20 and 21.

  Further, the curvature radius r4 of the right arc 23 is equal to the curvature radius r3 of the left arc 22, and is larger than the curvature radii r1 and r2 of the front and rear arcs 20 and 21, and r3 = r4> r1 = r2. . Therefore, the distance from the right arc 23 to the center of curvature p1 of the front and rear arcs 20 and 21 is smaller than the curvature radii r1 and r2 of the front and rear arcs 20 and 21, similar to the left arc 22, and the inner circumference 3 The thickness of the right portion 13 in the thickness changing portions 1a and 1b is thinner than the thickness of the front and rear portions 10 and 11.

  Further, as described above, the outer tube 1 is formed symmetrically so that the distances Δ1, Δ2 from the center of curvature p1 of the front and rear arcs 20, 21 to the center of curvature p2, p3 of the left and right arcs 22, 23, Since the radii of curvature r3 and r4 of the arcs 22 and 23 are equal and the center of the inner periphery 3 is p1, the thickness of the left portion 12 and the right portion 13 in the first and second thickness changing portions 1a and 1b. Are equal.

  Next, the outer tube processing method of the suspension device in the present embodiment will be described with reference to FIGS. The outer tube 1 is formed by turning a cylindrical base material 1A. And the inner periphery 3 and the outer periphery 2A of this base material 1A are concentric circles, and both are perfect circles.

  In the first step, as shown in FIG. 3A, the base material 1A is fixed to the chuck 5 that is eccentric with respect to the rotation center O of the rotating body 4 in the lathe. At this time, the chuck 5 is set so that the axis X of the base material 1 </ b> A deviates from the rotation center O of the rotating body 4 by Δ1.

  Next, the chuck 5 is rotated and the table on which the cutting tool 6 is fixed is moved. As shown in FIGS. 3B and 3C, the tip of the cutting tool 6 is brought into contact with the base material 1A, and the first and second The portions corresponding to the thickness changing portions 1a and 1b are shaved. At this time, since a part of the outer periphery of the base material 1A that is away from the rotation center O hits the cutting tool 6 when the base material 1A is rotated, it is cut into a crescent-shaped cross section by the cutting tool 6 and the wall thickness is reduced.

  Thereby, as shown in FIG.3 (d), one of the left part 12 or the right part 13 in the 1st, 2nd thickness change part 1a, 1b is formed.

  Next, in the second step, as shown in FIG. 4A, the base material 1A is rotated by 180 degrees and fixed to the chuck 5 set in the same manner as in the first step, and the first step of the base material 1A is performed. The part cut by (one of the left part 12 or the right part 13) is set to be positioned on the byte side. For this reason, the axis X of the base material 1A deviates from the rotation center O of the rotating body 4 by Δ1 in the opposite direction to the first step.

  Next, the chuck 5 is rotated and the table on which the cutting tool 6 is fixed is moved. As shown in FIGS. 4B and 4C, the tip of the cutting tool 6 is brought into contact with the base material 1A, and the first and second The portions corresponding to the thickness changing portions 1a and 1b are shaved. At this time, the outer periphery of the base material 1A opposite to the portion cut in the first step (one of the left portion 12 or the right portion 13) hits the cutting tool 6 and is cut into a crescent-shaped cross section by the cutting tool 6 so that the wall thickness is thin. Become.

  Thereby, as shown in FIG.4 (d), the other of the left part 12 or the right part 13 in the 1st, 2nd thickness change part 1a, 1b is formed, and the outer tube 1 is completed.

  That is, by forming the outer tube 1 from the cylindrical base material 1A by the above method, the portions not cut by the cutting tool 6 in the first and second thickness changing portions 1a and 1b are the front and rear portions 10 and 11. It becomes.

  For this reason, when the thickness changing portions 1a and 1b are cut in the radial direction, the front and rear arcs 20 and 21 are a part of the outer periphery 2A of the base material 1A formed in a perfect circle. The centers of curvature p1 of the arcs 20 and 21 are on the axis X and are at the same position, and the radii of curvature r1 and r2 of the front and rear arcs 20 and 21 are equal.

  Further, by fixing the axis X of the base material 1A from the rotation center O of the rotating body 4 in the lathe by Δ1 while being fixed to the chuck 5, and cutting away the part away from the rotation center O with the cutting tool 6, the base material 1A A part of the outer periphery of the first and second parts is cut into a crescent shape to form left and right portions 12 and 13 in the first and second thickness changing portions 1a and 1b.

  For this reason, when each thickness change part 1a, 1b is cut | disconnected in radial direction, the curvature center p2 of the left circular arc 22 turns into the position of one rotation center O of a 1st process or a 2nd process, 11 is shifted to the right of Δ1 from the center of curvature p1. Further, the curvature radius r3 of the left arc 22 is larger than the curvature radii r1 and r2 of the front and rear arcs 10 and 11.

  On the other hand, the center of curvature p3 of the right arc 23 is the position of the other rotation center O in the first step or the second step, and is opposite to the center of curvature p2 of the left arc 12 from the center of curvature p1 of the front and rear arcs 10 and 11. Δ1 (= Δ2) is shifted to the side. Further, the curvature radius r4 of the right arc 23 is equal to the curvature radius r3 of the left arc 22, and is larger than the curvature radii r1 and r2 of the front and rear arcs 20 and 21.

  Next, the effect of the suspension apparatus according to the present embodiment will be described. In the present embodiment, the outer tube 1 has first and second thickness changes in which the thickness of the left and right portions 12 and 13 is formed thinner than the thickness of the front and rear portions 10 and 11 in the traveling direction of the vehicle body. Part 1a, 1b is provided.

  Therefore, the thickness of the front and rear portions 10 and 11 of the first and second thickness changing portions 1a and 1b is increased to increase the rigidity against the force acting in the front-rear direction toward the traveling direction of the vehicle body. It is possible to reduce the weight by reducing the thickness of the portions 12 and 13.

  Further, the outer periphery 2 of the first and second thickness changing portions 1a, 1b is composed of front, rear, left and right arcs 20, 21, 22, 22, 23 in the traveling direction of the vehicle body, and the center of curvature of the front and rear arcs 20, 21 is p1 is the same and the radii of curvature r1 and r2 of the front and rear arcs 20 and 21 are equal (r1 = r2).

  Furthermore, the respective curvature centers p2 and p3 of the left and right arcs 22 and 23 are shifted to the right and left sides (directions away from the respective arcs 22 and 23) from the curvature centers p1 of the front and rear arcs 20 and 21, respectively. , 23 are formed larger than the radii of curvature r1, r2 of the front and rear arcs 20, 21 (r3, r4> r1, r2).

  For this reason, the said shape of the said outer tube 1 can be implement | achieved by lathe processing, and even if the outer tube 1 is equipped with the thickness change parts 1a and 1b, the process for forming the outer tube 1 conventionally is carried out. Simple and efficient.

  Furthermore, in the present embodiment, the curvature centers p2, p3 of the left and right arcs 22, 23 in the first and second thickness changing portions 1a, 1b are symmetrical about the curvature centers p1 of the front and rear arcs 20, 21. The curvature radii r3 and r4 of the left and right arcs 22 and 23 are formed equally (r3 = r4).

  For this reason, after forming one of the left part 12 or the right part 13 of the first and second thickness changing parts 1a, 1b, the left part 12 or the right part 13 can be changed only by changing the orientation of the base material 1A. The other can be formed, and even if the thickness of both the left portion 12 and the right portion 13 is reduced, it is not necessary to reset the chuck 5 and the lathe can be efficiently processed.

  Although preferred embodiments of the present invention have been described in detail above, it should be understood that modifications, variations and changes may be made without departing from the scope of the claims.

  For example, the suspension device according to the above embodiment is an inverted front fork that suspends a front wheel in a straddle-type vehicle such as a motorcycle.

  Moreover, in the said embodiment, although the thickness of the left-right parts 12 and 13 of the thickness change parts 1a and 1b in the outer tube 1 is formed thinner than the thickness of the front-and-rear parts 10 and 11, the left part 12 Alternatively, only one thickness of the right portion 13 may be formed thin.

  In this case, the curvature centers p2 and p3 of the left or right arcs 22 and 23 corresponding to the left portion 12 or the right portion 13 formed with a small film thickness are away from the arcs 22 and 23 (in the case of the left arc 22). Is shifted to the right side and the left side in the case of the right arc 23, and the curvature radii r3 and r4 of the left or right arcs 22 and 23 corresponding to the left part 12 or the right part 13 formed with a small film thickness are If the radii of curvatures r1 and r2 of the arcs 20 and 21 are larger than those of the arcs 20 and 21, the rigidity with respect to the force acting in the front-rear direction toward the traveling direction of the vehicle body is increased and the weight is reduced as in the above-described embodiment. can do.

  Also in this case, since the outer tube can be formed by lathe processing, the processing of the outer tube can be made simpler and more efficient than before.

  In the above embodiment, the curvature centers p2 and p3 of the left and right arcs 22 and 23 are shifted symmetrically about the curvature center p1 of the front and rear arcs 20 and 21, and the curvature radii of the left and right arcs 22 and 23 are the same. Although r3 and r4 are the same, this is not restrictive, and the amounts Δ1 and Δ2 of deviation of the center of curvature p2 and p3 of the left and right arcs from the center of curvature of the front and rear arcs 20 and 21 are different. The radii of curvature r3 and r4 may be different (Δ1 ≠ Δ2, r3 ≠ r4).

  In this case, a lathe provided with a chuck 5 in which the axis X of the base material 1A is set to be shifted by Δ1 from the rotation center O of the rotating body 4, and the axis X of the base material 1A is the rotating body 4. By preparing a lathe provided with a chuck (not shown) set so as to be shifted by Δ2 from the rotation center O, lathe processing can be performed efficiently.

  In the above embodiment, the outer tube 1 can be easily formed by a lathe process for rotating the base material 1A. However, the outer tube may be rotated by a method other than the lathe process. 1 may be formed.

  Moreover, in the said embodiment, although the outer tube 1 is equipped with the 1st, 2nd thickness change part 1a, 1b, it is possible to select the number and range of this thickness change part suitably. .

DESCRIPTION OF SYMBOLS 1 Outer tube 1A Base material 1a, 1b Thickness change part 1c, 1d Attachment part 2, 2A Outer periphery 3 Inner periphery 4 Rotor 5 Chuck 6 Bit 10 Front part 11 Rear part 12 Left part 13 Right part 20, 21, 22, 23 Arc B Bracket B1 Upper bracket B2 Under bracket

Claims (5)

An outer that is formed in a cylindrical shape and includes at least one thickness changing portion in which at least one of the left portion and the right portion is thinner than the front and rear portions in the traveling direction of the vehicle body In a suspension device with a tube,
The outer circumference of the thickness change part is composed of front, rear, left and right arcs, the center of curvature of the front and rear arcs is the same, and the radius of curvature of the front and rear arcs is formed equally,
The center of curvature of at least one of the left and right arcs deviates from the center of curvature of the front and rear arcs in a direction away from at least one of the left and right arcs, and the curvature of at least one of the left and right arcs A suspension device characterized in that the radius is formed larger than the curvature radius of the front and rear arcs. The thickness of the left and right parts of the thickness change part is formed thinner than the thickness of the front and rear parts,
The center of curvature of the left arc is shifted to the right from the center of curvature of the front and rear arcs, and the radius of curvature of the left arc is formed larger than the radius of curvature of the front and rear arcs,
The center of curvature of the right arc is shifted to the left from the center of curvature of the front and rear arcs, and the radius of curvature of the right arc is formed larger than the radius of curvature of the front and rear arcs. The suspension device according to claim 1.   3. The suspension device according to claim 2, wherein the center of curvature of the left and right arcs is symmetrically shifted with respect to the center of curvature of the front and rear arcs, and the radius of curvature of the left and right arcs is equal. .   The outer tube is formed by lathing a cylindrical base material, and the base material is fixed to a chuck eccentric with respect to the rotation center of the rotating body, and the left part or the right side in the thickness changing portion The suspension according to claim 2 or 3, wherein after forming one of the portions, the base material is rotated 180 degrees and fixed to the chuck to form the other of the left portion or the right portion. apparatus. In the outer tube processing method of the suspension device, which is formed in a cylindrical shape, the inner periphery and the outer periphery are concentric circles and a base material that is a perfect circle is turned to form an outer tube,
A first step of fixing the base material to a chuck eccentric with respect to a rotation center of a rotating body in a lathe, and cutting a part of the outer periphery of the base material away from the rotation center;
The base material is rotated by 180 degrees and fixed to the chuck set in the same manner as in the first step, and a part of the outer periphery located on the opposite side to the portion of the base material shaved in the first step is fixed. And a second step of cutting. A method for processing an outer tube of a suspension device.

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