JP5451679B2 - Caster production method - Google Patents

Description

  The present invention relates to a method for manufacturing a caster attached to equipment or a transport vehicle.

  Conventionally, this type of caster is such that, for example, a top plate of a wheel frame is rotatably attached via a bearing to a lower side of a base fixed to the bottom of equipment or a transport vehicle, The bearing is accommodated in the bearing case, and the bearing case is fixed to the top plate of the wheel frame (Patent Document 1).

JP-A-11-245607

  However, the conventional caster manufacturing method has a problem that the wheel frame and the bearing case are provided separately, which increases the time and effort required for mounting the bearing case to the wheel frame. It was.

  The present invention has been made in view of the above-described problems, and provides a caster manufacturing method that can improve manufacturability such as mounting stability when housing a bearing in a bearing case and can also improve bearing mounting accuracy. The purpose is to do.

In the first aspect of the present invention, a through portion is formed in a top plate of a wheel frame for holding a wheel, the top plate is extruded downward, and the through portion is formed into a cylindrical portion having a straight peripheral wall. The lower part of the peripheral wall is expanded to form a bearing case integrated with the wheel frame, the bearing is accommodated in the bearing case upward from below, and the upper part of the peripheral wall is held by the upper part of the peripheral wall. , Performing a drawing process for bending the periphery of the lower end of the bearing case inward, holding the lower part of the bearing, fixing the bearing to the bearing case, and in the process of forming the bearing case, The throttle portion is formed by reducing the diameter around the lower end to a size that allows the bearing to pass therethrough .

According to the first aspect of the present invention, since the wheel frame for holding the wheel and the bearing case for housing the bearing are integrally provided, the trouble of mounting the bearing case to the wheel frame is saved and the number of parts is increased. Thus, it is possible to provide a caster manufacturing method that can improve the manufacturability such as mounting stability when the bearing is accommodated in the bearing case, and can improve the mounting accuracy of the bearing. Further, the periphery of the lower end of the bearing case is a straight peripheral wall that is easy to be drawn, and a caster manufacturing method having excellent dimensional accuracy after drawing can be provided. In addition, if the diameter of the bearing case is reduced in advance around the lower end of the bearing case before the drawing process, the diameter of the lower end of the bearing case at the time of drawing is easily reduced. Dimensional accuracy is improved.

It is sectional drawing of the caster manufactured by the manufacturing method of this invention. It is sectional drawing which shows a state before forming a cylindrical part on the top plate of a wheel frame same as the above. It is sectional drawing which shows the state which formed the cylindrical part in the top plate of the frame for wheels same as the above. It is sectional drawing which shows the state which expanded the diameter of the lower part of the cylindrical part same as the above, and formed the bearing case. It is a sectional view showing the state before adhering a bearing to a bearing case same as the above. It is sectional drawing which shows the state which fixed the bearing to the bearing case same as the above. It is a perspective view which shows a state before adhering a bearing to a bearing case same as the above.

  Preferred embodiments of the present invention will be described with reference to the accompanying drawings. The embodiments described below do not limit the contents of the present invention described in the claims. In addition, all the configurations described below are not necessarily essential conditions of the present invention.

  1 to 7 show an embodiment of the caster of the present invention. The caster of the present embodiment rotates the top plate 4 of the wheel frame 3 via the bearing 2 such as a deep groove ball bearing on the lower side of the pedestal 1 fixed to the bottom of the transportation equipment or various transport vehicles. It is assumed to be mounted freely.

  The caster manufacturing method of the present embodiment shown in the figure is such that the base 1 and the inner ring 5 of the bearing 2 are fixed to the stop shaft 6, and the outer ring 8 of the bearing 2 is attached to the bearing case 7 formed on the top plate 4 of the wheel frame 3. By fixing, the top plate 4 of the wheel frame 3 is rotatably attached to the lower side of the base 1 via the bearing 2.

  Hereinafter, the caster manufacturing method of the present embodiment will be described with reference to the accompanying drawings. First, as shown in FIG. 2, a through portion 9 is formed in the center of the top plate 4 of the wheel frame 3. The through-hole 9 has a circular plane centered on X, and the top surface 4a of the top plate 4 is also a circular plane centered on X. When the diameter of the upper surface 4a is S, the through-hole 9 Have a relationship of S × 0.25 ≦ T ≦ S × 0.26.

  Next, as shown in FIG. 3, the top plate 4 is extruded from the top to the bottom of the top plate 4 in the center axis direction (X direction in the drawing) of the penetrating portion 9 in the vertical direction. The through-hole 9 is enlarged in diameter, and a cylindrical portion 11 having a substantially straight peripheral wall 10 is formed. Here, the peripheral wall 10 of the cylindrical portion 11 is formed in a straight shape parallel to the central axis direction (X direction in the drawing) of the cylindrical portion 11 from the upper end 12 to the lower end 13 adjacent to the top plate 4. Further, the inner diameter L1 of the cylindrical portion 11 is smaller than the outer diameter M1 of the outer ring 8 of the bearing 2 and larger than the inner diameter M2 of the outer ring 8 (M2 <L1 <M1).

  Subsequently, as shown in FIG. 4, the lower middle part from the middle part of the cylindrical part 11 slightly below the upper end 12 to the lower end 13 is extruded so that the middle part slightly below the upper end 12 of the peripheral wall 10 of the cylindrical part 11. A bottomed cylindrical bearing case 7 is formed by enlarging the lower part from the part to the lower end 13 (L1 <L2) and denting from below to above in the central axis direction (X direction in the figure) of the penetrating part 9. It is formed.

  Here, the inner diameter L2 of the lower peripheral wall 10 from the middle part of the cylindrical portion 11 slightly below the upper end 12 to the lower end 13 is formed to be slightly larger than the outer diameter M1 of the outer ring 8 of the bearing 2 (L2>). M1) A bottomed portion that is recessed from the lower part to the upper part in the central axis direction (X direction in the figure) of the penetrating part 9 at the lower part from the middle part to the lower end 13 slightly below the upper end 12 of the cylindrical part 11 An accommodation space 14 and an accommodation port 15 for accommodating the bearing 2 in the cylindrical bearing case 7 are formed.

  Further, on the upper part of the cylindrical part 11, a step part 16 capable of holding the upper part of the outer ring 8 of the bearing 2 is formed at the boundary between the upper end 12 formed on the inner diameter L1 and the middle part formed on the inner diameter L2. . And this level | step-difference part 16 comprises the bottom part in the bottomed cylindrical bearing case 7 dented from the downward direction to the upper direction in the center axis direction (X direction in the figure) of the penetration part 9. FIG.

  Next, as shown in FIG. 5, the bearing 2 is accommodated from the accommodation port 15 of the bearing case 7 from below to above in the central axis direction (X direction in the drawing) of the through portion 9.

  Finally, as shown in FIG. 6, the upper portion of the outer ring 8 of the bearing 2 is held by the stepped portion 16 at the upper portion of the bearing case 7, and the periphery of the lower end 13 of the cylindrical portion 11 that is the receiving port 15 of the bearing case 7 is further squeezed. The bearing 2 is fixed to the bearing case 5 by processing and holding the lower part of the outer ring 8 of the bearing 2.

  Here, the inner diameter L4 around the lower end 13 of the bearing case 7 is reduced within a range smaller than the outer diameter M1 of the outer ring 8 of the bearing 2 and larger than the inner diameter M2 of the outer ring 8 (M2 <L4). <M1).

  As shown in FIG. 1, the pedestal 1 is positioned above the inner ring 5 of the bearing 2, and washers (not shown) are arranged on the upper side, the lower side, or both sides of the inner ring 5, The base shaft 1 and the inner ring 5 of the bearing 2 are fixed to the stop shaft 6 by passing through the stop shaft 6 and the upper or lower portion of the stop shaft 6 is caulked. It rotates with the outer ring 8. Therefore, the wheel 18 pivotally supported on the side plate 17 of the wheel frame 3 can turn by the rotation of the top plate 4 of the wheel frame 3.

  In this case, since the bearing 2 has a groove in which neither shoulder of the inner ring 5 or the outer ring 8 is dropped, the spherical body 19 as the rolling element has no gap between the inner ring 5 and the outer ring 8. It will be held in a stable state. Further, the bearing case 7 in which the bearing 2 is accommodated is formed by extruding the top plate 4 of the wheel frame 3 and is integrated with the wheel frame 3, so that the bearing case 7 is not stable. There is no. Therefore, the top plate 4 of the wheel frame 3 that rotates together with the outer ring 8 does not rattle and does not become difficult to rotate, and the wheel 18 that is pivotally supported by the side plate 17 of the wheel frame 3 is also smooth. It will turn to.

  The pedestal 1 may be provided with an annular body 20 separate from the pedestal 1 between the pedestal 1 and the bearing 2 in order to provide an arrangement space for the top plate 4 between the pedestal 1 and the bearing 2. Moreover, it is good also as what provided the arrangement | positioning space of the top plate 4 as what provided the downward flange part in the base 1. FIG.

  Further, the shape of the wheel frame 3 is inverted so that the top plate 4 faces downward and the left and right side plates 17 face upward because the center of gravity is located near the top plate 4 integrally provided with the bearing case 7. When placed in a state of orientation, the center of gravity is low and the stability is good, that is, the so-called sitting shape is good.

  Therefore, each of the molding of the bearing case 7 by expanding the peripheral wall 10 of the cylindrical portion 11, the housing of the bearing 2 in the bearing case 7, and the drawing processing around the lower end 13 of the bearing case 7 shown in FIGS. In the process, it is preferable in the automation of the production line and the like that the work is performed in an inverted direction with the top plate 4 of the wheel frame 3 facing downward and the left and right side plates 17 facing upward (see FIG. 7).

  In this case, the operation direction of the press means for drawing, etc., which is performed from the bottom to the top in the central axis direction (X direction in the figure) of the cylindrical portion 11 is substantially equal to the direction of gravity, so that the pressing force of the press means, etc. In addition to facilitating the drawing process effectively by reducing the loss of the bearing, the housing 15 and the left and right side plates 17 face upward so that the bearing 2 can be accommodated and the wheels to the left and right side plates 17 thereafter. 18 can be easily attached, and a series of manufacturing processes are smoothly performed without any delay, so that work efficiency can be improved.

  Furthermore, the bearing case 7 is below the plane direction (Y direction in the drawing) of the top surface 4a of the top plate 4 with respect to the central axis direction (X direction in the drawing) of the penetrating portion 9 and the left and right side plates 17. It shall be formed between.

  In this case, the bearing case 7 does not protrude upward from the upper surface 4 a of the top plate 4 of the wheel frame 3 in the central axis direction (X direction in the drawing) of the through portion 9, and between the left and right side plates 17. By setting it as the structure arrange | positioned, the structure of the caster which integrally provided the flame | frame 3 for wheels and the bearing case 7 can be made compact.

  Further, in FIG. 4, by forming a throttle portion 21 in which the lower end 13 of the peripheral wall 10 of the cylindrical portion 11, which is the periphery of the housing port 15 of the bearing case 7, is slightly inclined inward, the housing port 15 of the bearing case 7 is formed. The inner diameter L3 of the bearing case 7 may be reduced within a size range (M1 <L3 <L2) in which the bearing 2 can pass through the accommodation port 15, and the accommodation port 15 of the bearing case 7 may be slightly narrowed in advance. .

  In this case, if the drawing portion 21 is formed by slightly reducing the diameter of the accommodation port 15 of the bearing case 7 in advance before the drawing process, the diameter of the accommodation port 15 of the bearing case 7 during drawing is reduced. Since it is easily performed, the dimensional accuracy during drawing is improved.

  In addition, as shown in FIG. 7, a circular arc surface 22 is formed at a base portion of the left and right side plates 17 with the top plate 4 so as to be parallel to the lower portion of the bearing case 7 with a predetermined distance. The pressing means (not shown) that moves in the central axis direction (X direction in the figure) of the bearing case 7 at the time of drawing around the lower end 13 of the peripheral wall 10 of the cylindrical portion 11 that is the receiving port 15 of the cylindrical portion 11 are left and right side plates 17. The structure is such that the movement of the pressing means (not shown) during drawing is not hindered by the left and right side plates 17.

  In addition, as shown in FIG. 6, the press surface of the bearing case 7 pressed by a pressing means (not shown) at the time of drawing is the peripheral wall 10 of the cylindrical cylindrical portion 11 that is the accommodation port 15 of the bearing case 7. The lower end 13 has a cross-sectional area in the direction (Y direction in the figure) orthogonal to the axial direction (X direction in the figure) of the bearing 2 which is the pressing direction, and the upper end 12 part of the cylindrical part 11 adjacent to the top plate 4 Compared with a simple shape that is small and easy to apply pressing means (not shown), drawing with high dimensional accuracy is possible with a single press, improving work efficiency and reducing the size with high dimensional accuracy. It is possible to stably hold the lower portion of the bearing 2 by the diameter containing opening 15.

  In addition, the step 16 is formed with high dimensional accuracy by forming the step 16 constituting the bottom of the bearing case 7 in advance by the extrusion process before the bearing 2 is accommodated in the bearing case 7. The upper part of the bearing 2 can be stably held.

  As described above, in the caster manufacturing method of the present application, the stepped portion 16 is formed in advance before the bearing 2 is accommodated in the bearing case 7, and the shape of the press surface during drawing is thin and simple. The lower end 13 of 11 allows the housing port 15 of the bearing case 7 in which the bearing 2 is accommodated to be drawn with high dimensional accuracy so that the bearing 2 can be housed and held in a stable state without rattling. Is done.

  In the caster completed as shown in FIGS. 1 and 6, the central axis direction of the through portion 9, the central axis direction of the cylindrical portion 11, the central axis direction of the bearing case 7, and the axial direction of the bearing 2 are coaxial. It shall be arranged in the direction (X direction in the figure).

  As described above, the caster manufacturing method of this embodiment forms the through-hole 9 in the top plate 4 of the wheel frame 3 that holds the wheels 18, pushes the top plate 4 downward, and forms the through-hole 9. After the cylindrical portion 11 having the straight peripheral wall 10 is formed, the lower portion of the peripheral wall 10 is expanded to form a bearing case 7 integrated with the wheel frame 3, and the bearing 2 is accommodated in the bearing case 7. The upper part of the bearing 2 is held by the step part 16 which is the upper part of 10, and the drawing process is performed by bending the periphery of the lower end 13 of the bearing case 7 inward to hold the lower part of the bearing 2, and the bearing 2 is fixed to the bearing case 7. To do.

  In this case, since the wheel frame 3 for holding the wheel 18 and the bearing case 7 for housing the bearing 2 are integrally provided, the trouble of mounting the bearing case 7 to the wheel frame 3 is saved and the number of parts is increased. Thus, it is possible to provide a caster manufacturing method that can improve the manufacturability such as the mounting stability when the bearing 2 is accommodated in the bearing case 7 and can improve the mounting accuracy of the bearing 2. Further, the periphery of the lower end 13 of the bearing case 7 is a substantially straight peripheral wall 10 which is easy to be drawn, and a caster manufacturing method having excellent dimensional accuracy after drawing can be provided.

  Further, in the process of forming the bearing case 7, the accommodating portion 15 around the lower end 13 of the bearing case 7 is reduced in diameter so that the bearing 2 can pass through (M1 <L3 <L2) to form the throttle portion 21. As a result, the diameter of the accommodation port 15 of the bearing case 7 is reduced when the drawing portion 21 is formed by slightly reducing the diameter of the accommodation port 15 of the bearing case 7 in advance before the drawing process. Therefore, the dimensional accuracy during drawing is improved.

  In addition, this invention is not limited to the said Example, A various deformation | transformation implementation is possible. For example, the shape of the wheel frame is not limited to the above embodiment, and can be changed as appropriate. The wheel 18 may be attached to the side plate 17 through a bearing or the like.

2 Bearing 3 Wheel frame 4 Top plate 7 Bearing case 9 Through part
10 wall
11 Cylindrical part
13 Bottom
18 wheels
21 Aperture

Claims (1)

Form a penetration in the top plate of the wheel frame that holds the wheel,
After extruding the top plate downward and forming the through portion into a cylindrical portion having a straight peripheral wall,
The lower part of the peripheral wall is expanded to form a bearing case integrated with the wheel frame,
A bearing is accommodated upward from below in the bearing case,
While holding the upper part of the bearing at the upper part of the peripheral wall, performing drawing processing to bend the lower end periphery of the bearing case inward, holding the lower part of the bearing,
The bearing is fixed to the bearing case ,
In the process of forming the bearing case, a method for manufacturing a caster is characterized in that the diameter of the periphery of the lower end of the bearing case is reduced to a size that allows the bearing to pass through to form a throttle portion .

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