Swivel wheel structure

Abstract

The invention relates to a rotating wheel construction that achieves noise reduction of a rotating wheel with thrust and radial bearings. The difference is that the upper ring S1 of the thrust bearing S is supported by a wheel mounting plate 1, the lower ring S2 is clamped by the flat surface of the support fork 3, the upper surface of the inner ring R1 of the radial bearing R is fixed by a washer, and the lower surface of the inner ring is fixed by a washer 5 on the lower end of the rotating shaft, wherein the upper surface of the outer ring of the radial bearing is hooked by the angle of the support fork and fixed.

Description

Swivel caster structure

[0001] The present invention relates to a swivel caster structure with excellent noise reduction effect, which is used as a wheel for transport equipment, various transport vehicles, carts, etc.

[0002] In the caster and carriage disclosed in Japanese Patent Laid-Open No. 2007-22254 shown in Patent Document 1, in the second embodiment shown in Figures 6 to 8 of the publication of Patent Document 1, a caster mounting plate, a thrust bearing, a first washer, a radial bearing (with a yoke portion fixed to the outer ring), and a second washer are inserted in this order onto the swivel shaft, and are arranged coaxially with the swivel shaft, and the end of the swivel shaft is crimped. This fixes (clamps) each member sandwiched between the flange portion and the end of the swivel shaft.

[0003] However, in the above configuration, the upper surface of the inner ring of the radial bearing is abutted against a separate large-diameter first washer between the thrust bearing and the radial bearing, and the lower surface of the outer ring of the radial bearing is supported by a recess in the yoke of the radial bearing, so there is a drawback in that loads are generated on the bearings separately and it is not possible to prevent noise during vibration.

[0004] Patent Publication No. 2007-22254

[0005] The present invention relates to a swivel caster structure that has a simple configuration and achieves noise reduction in a swivel caster having a thrust bearing and a radial bearing.

[0006] In order to solve the above problems, this invention provides a mounting plate having a mounting shaft with a flange at its upper end, a mounting hole through which the mounting shaft is inserted without any gap and through which the flange is latched, a downward horizontal surface formed on the back surface of the mounting plate, and a support yoke having a support yoke-side hole through which the mounting shaft is inserted below the mounting plate and having an upward horizontal surface formed parallel to the downward horizontal surface, the upper ring of a thrust bearing being supported on the downward horizontal surface and the lower ring of a thrust bearing being supported on the upward horizontal surface, an upward step portion rising from the base end side of the upward horizontal surface of the support yoke and extending in the direction of the swivel axis to the yoke-side hole, with an L-shaped cross section, a corner of the upward step portion latching onto the upper part of the outer ring of a radial bearing from above, the lower part of the outer ring being open, and a spacer portion hanging down along the swivel axis between the mounting hole and the upward step portion and having a lower end abutting against the upper end of the inner ring of the radial bearing, The lower end of the inner ring of the radial bearing is fixed to the lower end side of the mounting shaft.

[0007] This allows each component sandwiched between the flange portion and the lower end of the rotating shaft to be fixed together without any gaps, preventing each component from swinging individually and allowing the load to be borne efficiently. It also reduces the generation of vibrations and noise, ensuring quiet operation during driving.

[0008] Fig. 1 is a cross-sectional view of a main part of a swivel caster; Fig. 2 is a cross-sectional view of a main part with a dust cover for covering a bearing added; Fig. 3 is an enlarged view of the main part; Fig. 4 is a cross-sectional view of a main part showing a different embodiment; Fig. 5 is a longitudinal cross-sectional view of a caster; Fig. 6 is a plan view of the same; Fig. 7 is a front view of the same.

[0009] Preferred embodiments of the present invention will now be described with reference to the drawings.

[0010] An example of the swivel caster 20 of Example 1 is shown in Fig. 5 as viewed from a vertical cross section, Fig. 6 as a plan view, and Fig. 7 as a front view. The enlarged view of the main part shown in Fig. 1 shows a cross section along the axis of the swivel shaft 10, showing the structure around the swivel shaft 10. The swivel shaft 10 has a substantially cylindrical shape, and a flange portion 11 is formed on one side in the axial direction.

[0011] The swivel shaft 10 has a bearing mechanism built in between the caster mounting plate 1 and the support yoke 3 that supports the wheel W, and is fixed by the flange portion 11 and a crimped portion 12 that has a large diameter at the lower end to prevent it from coming loose.

[0012] That is, the caster mounting plate 1 has a substantially horizontal flat surface 2a, a mounting hole 1b at approximately the center of the plate 2a that has an inner diameter smaller than the outer diameter of the flange portion 11 of the head of the swivel shaft 10 and through which the shaft portion 10A of the swivel shaft 10 can be inserted, and a recessed portion 1c that extends along the outer periphery of the opening end of the mounting hole 1b and connects to the flat surface 1a.

[0013] The recessed portion 1c is recessed relative to the outer horizontal flat surface 2a around the periphery so that the recessed portion 1c is at approximately the same position as the thickness of the flange portion 11. The peripheral edge of the mounting hole 1b forms a horizontal surface for horizontally engaging the upper surface of the flange portion 11 of the swivel shaft 10, and the upper surface of the flange portion 11 engaged in the mounting hole 1b is set to be approximately the same plane as the flat surface 2a (see FIG. 5).

[0014] Next, the thrust bearing S is arranged on the outer periphery of the radial bearing R above the radial bearing R, and is interposed between the caster mounting plate 1 and the support yoke 3. In the illustrated example, the thrust bearing is arranged in close contact with the upper surface of the lower ring S2 of the thrust bearing and the upper end surfaces of the inner ring R1 and outer ring R2 of the radial bearing so that they are almost flush with each other in the height direction.

[0015] The upper surface of the upper ring S1 of the thrust bearing S abuts against the downward-facing horizontal surface 1a on the back surface of the caster mounting plate 1, and the bottom side of the lower ring S2 of the thrust bearing S abuts against the upward-facing horizontal surface 3a formed in the middle section (described later) of the support yoke 3, with the tip of the upward-facing horizontal surface 3a forming a hanging wall 3a' at a substantially right angle. Also, a yoke-side hole 30, which is concentric with and larger in diameter than the mounting hole 1b, is drilled in the upper part of the support yoke 3 at approximately the middle position on the top surface of the support yoke 3.

[0016] Furthermore, the tip of the upward step 3b adjacent to the upward horizontal surface 3a forms the rim of the hole 30 on the yoke side, and the upward step 3b of the support yoke 3 and a corner 3c on the inner surface form an upward step 3L with an L-shaped cross section, which abuts against the upper end of the outer ring R2 of the radial bearing R. Meanwhile, directly below the mounting hole 1b, a spacer part 4 with a cylindrical cross section made of a washer is attached. The spacer part 4 abuts against the rim of the mounting hole 1b, fits snugly around the swivel shaft 10, and hangs down to the same position as the corner 3c on the inner surface of the upward step 3b, and the lower end of the spacer part 4 abuts against the upper end of the inner ring R1 of the radial bearing R.

[0017] The lower end of the inner ring R1 of the radial bearing R is fixed by a crimped portion 12 at the lower end of the mounting shaft 10, or by a lower spacer portion 5 consisting of a lower washer hooked onto the crimped portion 12. Meanwhile, the lower end of the outer ring R2 of the radial bearing R is open in a hollow position. With the above-described configuration, the thrust bearing S has open outward sides of its upper and lower rings S1 and S2, and the lower end of the outer ring R2 of the radial bearing R is open, achieving a noise reduction effect with a simple configuration. The upward step 3b and inner corner 3c of the support yoke 3 on the wheel reverse side form an upward step 3L with an L-shaped cross section, which extends from the upward horizontal surface 3a through a mid-step 3d to a rear horizontal surface 3e, forming a hanging wall 3e' at a substantially right angle at its tip.

[0018] In the second embodiment shown in Figure 2, a dust cover 6 made of a flexible and elastic synthetic resin or the like is attached below the mounting plate 1 and covers the outer periphery of the thrust bearing S except for the bottom surface. The dust cover 6 is attached to overlap the back surface of the mounting plate 1 and performs the same function as the mounting plate 1 by overlapping with the downward horizontal surface 1a, so a description of it will be omitted. The rest of the configuration is the same as in the first embodiment, so a description will be omitted.

[0019] In Example 3 shown in Figure 3, instead of the separate washer-shaped spacer portion 4, a spacer portion 4' is formed integrally with the mounting hole 1b and is a downwardly extending cylindrical wall portion with the same inner diameter as the hole edge. The lower end of spacer portion 4', which forms the downwardly extending wall portion, abuts without any gap against the upper end surface of the inner ring R1 of the radial bearing R, distributing the load on the center side of the caster mounting plate 1 to the inner ring R1 of the radial bearing R. The rest of the configuration is the same as in Example 1, so a description thereof will be omitted.

[0020] In Example 4 shown in FIG. 4, similar to Example 3 shown in FIG. 3, instead of the separate washer-shaped spacer portion 4, a hanging wall portion that is formed integrally with the mounting hole 1b and extends downward in a cylindrical shape with the same inner diameter as the hole edge portion is formed as a spacer portion 4'.

[0021] The lower end of the spacer portion 4', which forms the hanging wall portion, abuts the upper end surface of the inner ring R1 of the radial bearing R without any gap, distributing the load on the center side of the caster mounting plate 1 to the inner ring R1 side of the radial bearing R. Furthermore, the lower end of the inner ring R1 of the radial bearing R is hooked and fixed to a step 12a formed on the crimped portion 12 at the lower end of the mounting shaft 10 without providing a lower step spacer portion 5. The other configurations are the same as those of the above-mentioned embodiment, so their explanation will be omitted.

[0022] REFERENCE SIGNS LIST 1 Mounting plate 1a Downward horizontal surface 1b Mounting hole 3 Support yoke 3a Upward horizontal surface 3b Upward step portion 4, 4' Spacer portion 5 Lower step spacer portion 10 Mounting shaft 11 Flange 12 Crimping portion 13 Lower end hook portion 30 Hole on support yoke side S Thrust bearing S1 Upper ring S2 Lower ring R Radial bearing R1 Inner ring R2 Outer ring W Wheel

Claims

1. A mounting shaft having a flange on its upper end, a mounting plate having a mounting hole through which the mounting shaft is inserted without any gaps and through which the flange is hooked, a downward horizontal surface formed on the rear surface of the mounting plate, and a support yoke having a hole on the support yoke side through which the mounting shaft is inserted below the mounting plate and an upward horizontal surface formed parallel to the downward horizontal surface, the upper ring of a thrust bearing is supported on the downward horizontal surface, and the lower ring of a thrust bearing is supported on the upward horizontal surface, an upward step portion that rises at the base end side of the upward horizontal surface of the support yoke and extends in the direction of the swivel axis to the hole on the yoke side and has an L-shaped cross section, a corner of the upward step portion hooks onto the upper part of the outer ring of a radial bearing from above, the lower part of the outer ring being open, and a spacer portion that hangs down along the swivel axis between the mounting hole and the upward step portion and whose lower end abuts against the upper end of the inner ring of the radial bearing, the lower end of the inner ring of the radial bearing is fixed to the lower end side of the mounting shaft, The swivel caster structure is characterized in that the outward sides of the upper and lower wheels of the thrust bearing, which are sandwiched between the mounting plate and the support yoke from above and below, are open and not latched, and the lower end of the outer wheel of the radial bearing is open and not latched.

2. A swivel caster structure as described in claim 1, characterized in that the spacer portion is separate from the mounting plate and has a washer shape fitted onto the mounting shaft.

3. A swivel caster structure as described in claim 1, characterized in that the spacer portion comprises a hanging wall that hangs down along the edge of the mounting hole in the mounting plate and fits externally onto the mounting shaft.

4. A swivel caster structure as described in claim 1, characterized in that the lower end of the inner ring of the radial bearing is fixed to the step portion of the crimped portion at the lower end of the mounting shaft.

5. A swivel caster structure as described in claim 1, characterized in that the lower end of the inner ring of the radial bearing comprises a lower spacer portion fitted onto the lower end of the mounting shaft and fixed by a crimping portion.

6. A swivel caster structure as described in any one of claims 1 to 5, characterized in that the upper surface of the lower ring of the thrust bearing and the upper end surfaces of the inner ring and outer ring of the radial bearing are arranged in close contact with each other in the vertical direction so as to be flush with each other.

Images