JP2003113852A - Tightening structure of rotating body with shaft - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the tightening man hour of a pulley to a shaft. SOLUTION: A male screw part 211 is formed over a predetermined range from a tip side of a shaft 210, and a width across flat part 212 formed with a part of the male screw part 211 notched is provided on the tip side of the shaft 210 out of the male screw part 211. Since the tip side of the shaft 210 functions as a tap to remove dacuronium deposit of a female screw part 131, and the male screw part 211 except the width across flat part 212 is coupled with the male screw part 131 with dacuronium deposit removed therefrom. Therefore, any step of removing dacuronium deposit need not be provided separately, and the assembly man-hour (a period of time) in assembling the pulley 100 is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fastening structure for a rotating body and a shaft, which is effective when applied to a pulley mounting structure.

[0002]

2. Description of the Related Art As a pulley mounting structure, for example, in the invention disclosed in Japanese Utility Model Laid-Open No. 2-67152, a male screw portion is formed on a shaft, and a female screw portion is formed on a hub attached to the pulley, and both are screwed. It is concluded by joining.

[0003]

By the way, depending on the material of the hub attached to the pulley, it is necessary to form a film for preventing corrosion in order to improve the corrosion resistance of the inner hub. When the coating film for corrosion prevention is formed, the solution for forming the coating film is accumulated by surface tension so as to fill the valley portion of the internal thread portion, and the internal thread portion is crushed by the coating film.

Therefore, when assembling the inner hub on which the corrosion-preventing film is formed on the shaft, before the hub is assembled on the shaft, the film accumulation accumulated so as to fill the valley of the female screw portion is removed by tapping or the like. Therefore, the number of assembling steps for assembling the hub increases.

To solve this problem, a method of forming a female thread portion after forming a film for corrosion prevention can be considered. However, in this method, a step of forming a film occurs during the mechanical process of manufacturing the hub. Therefore, it is necessary to move the hub (workpiece) back and forth between the machine factory (the site where the mechanical process is performed) and the surface treatment factory (the site where the film forming process is performed), which deteriorates the manufacturing man-hour (productivity). Will end up.

In view of the above points, it is an object of the present invention to reduce the number of steps for fastening a rotating body and a shaft.

[0007]

In order to achieve the above object, the present invention provides a fastening structure for a rotating body and a shaft, wherein the rotating body (100) comprises:
A hole (132) having a female screw portion (131) is provided, and a male screw portion (211) that meshes with the female screw portion (131) is provided over a predetermined range from the tip of the shaft (210). A groove portion (212) in which a part of the male screw portion (211) is missing and a part of the outer peripheral surface of the shaft (210) is depressed is provided on the tip side of the shaft (210) of the (211). Is characterized by.

As a result, the tip side of the shaft (210) functions like a tap, so that the internal thread portion (13
Even if a film pool is formed on 1), the shaft (21
0) is screwed into the rotating body (100), the male thread portion (211) remaining on the tip side of the shaft (210) removes the coating so as to crush it, and
The fragments of the film pool removed by the rotation of the male screw part (211) collect in the groove part (212).

Therefore, the male screw portion (211) after the groove portion (212) is joined to the female screw portion (131) from which the film accumulation has been removed (crushed) on the tip side of the shaft (210). It is not necessary to separately provide a step of removing the accumulated coating film so as to fill the valley portion of the female screw portion (131) before assembling the rotating body (100) to the shaft (210). As a result, the man-hours (hours) for assembling the rotating body (100) without forming the internal thread portion (131) after forming the corrosion preventing film.
Can be reduced.

According to a second aspect of the present invention, there is provided a fastening structure between a rotating body and a shaft, wherein the rotating body (100) is provided with a hole (132) having a female screw portion (131) formed therein. A male screw part (211) that meshes with the female screw part (131) is provided over a predetermined range from the tip of the shaft (210), and the shaft (2) of the male screw part (211) is further provided.
On the tip side of 10), a part of the male screw part (211) is cut off to provide a double width part (212) consisting of two surfaces parallel to each other with the center (O) of the shaft (210) sandwiched therebetween. It is characterized by

As a result, the tip side of the shaft (210) functions like a tap, so that the internal thread (13
Even if a film pool is formed on 1), the shaft (21
0) is screwed into the rotating body (100), the male thread portion (211) remaining on the tip side of the shaft (210) removes the coating so as to crush it, and
The fragments of the film pool removed by the rotation of the male screw part (211) are pooled in the width across flats (212).

Therefore, in the male screw portion (211) after the double width portion (212), the film accumulation is removed (crushed) at the tip side of the shaft (210).
1), so that the female screw part (131) is attached before the rotating body (100) is assembled to the shaft (210).
It is not necessary to separately provide a step of removing the accumulated coating film so as to fill the valley portion of the. As a result, it is possible to reduce the assembly man-hour (time) when assembling the rotating body (100) without forming the internal thread portion (131) after forming the corrosion preventing film.

In the invention according to claim 3, the width across flats (2
12) is characterized in that it is formed in a tapered shape so that the diameter dimension (d) is reduced toward the tip side of the shaft (210).

As a result, like the tap or tapping screw, it is possible to easily remove the film accumulation accumulated in the trough of the female screw portion (131).

Incidentally, the reference numerals in the parentheses of the above-mentioned respective means are examples showing the correspondence with the concrete means described in the embodiments described later.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION (First Embodiment)
The present invention is applied to a fastening structure of a rotating body and a shaft for a fastening structure of a pulley (rotating body) that transmits a driving force of an engine (driving source) to a compressor of a vehicle air conditioner. 3 is a cross-sectional view of the pulley 100 showing a state in which the pulley 100 is assembled to the shaft 210 of the compressor 200. FIG.

In FIG. 1, 110 is a V-belt (not shown).
Is a pulley main body made of metal or hard resin (phenol resin in this embodiment) formed into a substantially cylindrical shape that rotates by receiving a driving force (torque) from a traveling engine (not shown) via On the inner peripheral side of the pulley body 110, a pulley cylindrical portion 111 to which a radial rolling bearing (hereinafter abbreviated as bearing) 120 that rotatably supports the pulley body 110 is mounted is integrally formed. Incidentally, the inner ring of the bearing 120 is mounted on the front housing of the compressor 200.

In this embodiment, the pulley body 110 is used.
As a pulley for a poly drive belt provided with a plurality of rows of V grooves 112 is adopted, and the pulley main body 110 is made of resin, the pulley cylindrical portion 1
A metallic sleeve 113 is integrated with the pulley cylindrical portion 111 by insert molding on the inner peripheral side of the bearing 11 where the bearing 120 is mounted (press-fitted).

Reference numeral 130 denotes an inner hub made of metal which is located on the inner peripheral side of the pulley main body 110 and is arranged coaxially with the pulley main body 110 to rotate. The outer peripheral side of the inner hub 130 is harder than the inner hub 130. Low elastic material (in this embodiment, EPDM (ethylene / propylene /
It is mechanically engaged (engaged) with the pulley main body 110 on the inner peripheral side of the pulley main body 110 via a damper (torque transmission member) 140 composed of a diene terpolymer rubber).

The inner hub 130 is the compressor 2
Male screw part 2 formed on the outer peripheral surface of the shaft 210 of 00
11, a cylindrical portion 133 having a through hole 132 formed with a female screw portion 131 that is screwed to the eleventh portion, an annular portion 135 having a protrusion 134 that engages with the damper 140, and the annular portion 135 and the cylindrical portion 133 are mechanically connected. Then ring 13
5 is transmitted from the annular portion 135 to the cylindrical portion 133 and the strength is set so as to break when the torque transmitted from the annular portion 135 to the cylindrical portion 133 exceeds a predetermined torque (in the present embodiment, 3) bridge section 136
(See FIG. 2) and the like.

The bridge portion 136 and the cylindrical portion 133 are integrally formed by sintering metal powder, and the bridge portion 136 and the annular portion 135 are formed by integrally forming the bridge portion 136 and the cylindrical portion 133. The annular portion 135 is integrated by injecting the resin into the mold (insert molding) in a state of being arranged in the mold for resin molding.

Further, the inner hub 130 has at least the female screw portion 131 formed thereon, and then has a coating for corrosion prevention formed on the surface thereof by the dacro treatment. In addition, the Dakuro treatment is performed by immersing the object to be treated in a decomposition aqueous solution (treatment solution) of metallic zinc flakes, chromic anhydride, etc., and then heating the object to be treated at about 300 ° C. in a baking furnace,
Hexavalent chromium is reduced by an organic substance such as glycol to bond zinc flakes to an object to be treated to form a film. By the way, chromic anhydride oxidizes the surface of the metal substrate to chemically bond with the object to be treated, thereby generating a strong adhesive force.

By the way, as shown in FIG. 3, the male screw portion 211 formed on the shaft 210 is formed over a predetermined range from the tip of the shaft 210 toward the housing of the compressor 200, and the male screw portion is formed. On the tip side of the shaft 210 of the 211, a two-face width portion (groove portion) 212 is provided, which is formed by omitting a part of the male screw portion 211 and sandwiching the center O of the shaft 210 and being parallel to each other. .

Next, the general operation of the joint 100 according to this embodiment will be described.

The torque transmitted to the pulley body 110 is
It is transmitted to the inner hub 130 via the damper 140. At this time, the damper 140 compressively deforms in the rotation direction (circumferential direction) of the pulley 110, thereby transmitting torque from the pulley 110 to the inner hub 130 while absorbing torque fluctuation.

Then, from the pulley 110 to the inner hub 1
When the torque transmitted to 30 reaches or exceeds a predetermined value, the bridge portion 136 breaks, so that the torque transmission from the pulley body 110 to the cylindrical portion 133 is interrupted. That is, the bridge portion 136 functions as a torque limiter mechanism that prevents the transmission of torque equal to or greater than a predetermined value.

Next, the features (effects) of this embodiment will be described.

In this embodiment, a film for preventing corrosion (thickness: about 3) is formed by forming a female screw portion 131 and then performing a dacro treatment.
0 μm), the surface tension acting on the treatment solution during the dacro treatment causes the internal thread portion 1 to move as shown in FIG.
A dakuro pool (clump of the processing solution) is generated in the valley portion 31.

However, in this embodiment, the male screw portion 211
Of the shaft 210, a double-sided width portion (groove) 212 formed by removing a part of the male screw portion 211 is provided on the tip side of the shaft 210. Therefore, the tip side of the male screw portion 211 functions like a tap and functions as a shaft. When the 210 (male screw portion 211) is screwed into the pulley 100 (female screw portion 131), the male screw portion 211 remaining on the tip side of the shaft 210 removes the Dakuro pool so as to be crushed and rotates the male screw portion 211. The fragments of the Dacro pool removed by the above process are pooled in the width across flats (grooves) 212.

Therefore, the male screw portion 211 after the width across flats (groove portion) 212 is connected to the female screw portion 131 from which the Dacro pool has been removed (crushed) at the tip side of the shaft 210, so that the pulley 100 shaft 210
It is not necessary to separately provide a step of removing the accumulated Dacro pool so as to fill the valley portion of the female screw portion 131 before assembling. As a result, it is possible to reduce the assembly man-hour (time) when assembling the pulley 100 without forming the female screw portion 131 after forming the corrosion prevention film (dacro treatment).

When assembling the pulley 100 to the shaft 210, the pulley 100 is rotated while the shaft 210 is restricted from rotating by a tool such as a wrench that fits into the flat width portion 212, and the male screw portion 211 is rotated. And the female screw portion 131 are coupled. Incidentally, it is desirable that the direction of the screw is such that the screw is tightened when a driving torque is applied.

(Second Embodiment) In the present embodiment, as shown in FIG. 5, the diameter dimension d is reduced as the width across flats (212) moves toward the tip side of the shaft 210 (male thread portion 211). It is formed in a tapered shape.

As a result, it is possible to easily remove the Dacro pool accumulated in the troughs of the female thread 131, like a tap or tapping screw.

(Other Embodiments) In the above-mentioned embodiments, the inner hub 130 is formed with the corrosion preventing film by the dacro treatment, but the present invention is not limited to this, and it is formed by other methods. It is also effective for the formed coating. Of course, it goes without saying that the present invention can be applied to the inner hub 130 on which no coating is formed.

In the above-described embodiment, the double width portion 212 is formed on the tip side of the male screw portion 211, but the present invention is not limited to this, and for example, instead of the double width portion 212, the shaft 210 of the shaft 210. It may be a simple groove in which a part of the outer peripheral surface is depressed.

[Brief description of drawings]

FIG. 1 is a sectional view showing a pulley mounting structure according to a first embodiment of the present invention.

FIG. 2 is a front view of the pulley according to the first embodiment of the present invention.

FIG. 3 is an explanatory view showing a pulley mounting structure according to the first embodiment of the present invention.

FIG. 4 is an enlarged view of an internal thread portion of the pulley according to the first embodiment of the present invention.

FIG. 5 is an explanatory diagram showing a pulley mounting structure according to a second embodiment of the present invention.

[Explanation of symbols]

100 ... Pulley (rotating body), 131 ... Female screw part, 210
... Shaft, 211 ... Male screw part, 212 ... Width across flats.

Claims (3)

[Claims] 1. A fastening structure for a rotating body and a shaft, wherein the rotating body (100) is provided with a hole (132) in which a female screw portion (131) is formed. A male screw portion (211) that meshes with the female screw portion (131) is provided over a predetermined range from the tip, and the male screw portion (211) is further provided on the tip side of the shaft (210) of the male screw portion (211). (2) is provided with a groove portion (212) in which a part of the outer peripheral surface of the shaft (210) is depressed so that the shaft (210) is provided with a groove portion (212). 2. A fastening structure between a rotating body and a shaft, wherein the rotating body (100) is provided with a hole (132) having a female screw portion (131) formed therein. A male screw portion (211) that meshes with the female screw portion (131) is provided over a predetermined range from the tip, and the male screw portion (211) is further provided on the tip side of the shaft (210) of the male screw portion (211). (2) is a part of which is missing, and the width across flats (212) is formed by two surfaces parallel to each other with the center (O) of the shaft (210) sandwiched therebetween.
A fastening structure between a rotating body and a shaft, wherein: 3. The double-width portion (212) is formed in a tapered shape so that the diameter dimension (d) decreases toward the tip side of the shaft (210). The fastening structure between the rotating body and the shaft according to 1 or 2.