JP2005133867A - Coupling structure of shaft and ring - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coupling structure of a shaft and a ring which can secure sufficient fitting force when press-fitting the ring on the shaft on which oil such as slushing oil remains. <P>SOLUTION: When the shaft 20 is press-fitted in the ring 103, the oil remaining on a fitting portion 21 of the shaft 20 to be fitted in the ring 103 is scraped and received in recess portions 22 formed in an outer surface 20a of the shaft 20. In order to obtain the sufficient fitting force at this time, since it is necessary to secure a certain or more contact area in the fitting portion 21 of the shaft 20 to be fitted in the ring 103, the rate of the area of the recess portions 22 to that of the outer surface 20a of the shaft 20 is set at 20 to 40%. Thus, it is possible to secure the sufficient fitting force and to enhance the drawing power when the shaft 20 is press-fitted in the ring 103. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a coupling structure of a shaft body and an annular body, and for example, relates to a coupling structure of a shaft body and an annular body that can couple a pulley sheet for attaching a pulley to a shaft of a water pump bearing used in an automobile.

Conventionally, as a coupling structure of a shaft body and an annular body, for example, a structure applied to a water pump shaft has been disclosed (see, for example, Patent Document 1).
As shown in FIG. 5, in this coupling structure of the shaft body 50 and the ring body (not shown), a recess 52 is provided on at least one of the outer peripheral surface 51 of the shaft body 50 and the inner peripheral surface of the hole of the ring body, When the body 50 is press-fitted, the oil film of the rust preventive oil remaining on the mating surface is blocked by the edge of the recess 52, and the oil film is scraped off.
However, in the coupling structure of the shaft body 50 and the ring body disclosed in Patent Document 1, the oil film at the rear portion of the recess 52 is not scraped off. For this reason, this part is in a state of insertion friction, and when the press-fitting is advanced, there is a case in which the “fitting” occurs and the press-fitting operation becomes difficult.

Therefore, a coupling structure of a shaft and a ring as shown in FIG. 6 has been considered (see, for example, Patent Document 2).
As shown in FIGS. 6 and 7, this shaft / ring coupling structure 110 may be used for the water pump 100, for example. In the water pump 100, the pump housing 101 is attached to an engine block (not shown), and a coupling structure 110 of a shaft body and an annular body is used in a hole portion of the pump housing 101. That is, the outer ring 112 of the bearing device 111 is attached to the hole of the pump housing 101, and the pump shaft 113 is rotatably supported as an inner ring. A pump rotor 102 is press-fitted and fixed to one end (right end in FIG. 7) of the pump shaft 113, and a pulley seat 103 is press-fitted to the other end (left end in FIG. 7).

As shown in FIG. 7, the bearing device 111 is arranged between a long cylindrical outer ring 112, one end side of the outer ring 112 and the pump shaft 113, and is held at equal intervals in the circumferential direction by a cage 114. And a plurality of cylindrical rollers 117 disposed between the other end side of the outer ring 112 and the pump shaft 113 and held by the retainer 116 at equal intervals in the circumferential direction.
At one end of the pump shaft 113, a plurality of grooves 118 having a substantially V-shaped cross section inclined with respect to the shaft center are provided in parallel and discontinuously in the circumferential direction. As a result, in the press-fitting process, there is some oil scraping due to the edge of the groove 118, but since a smooth surface exists between the adjacent grooves 118, a continuous oil film remains over the entire area of the fitting surface and the boundary. The press-fitting is performed smoothly in a friction state.
Japanese Utility Model Publication No. 63-115926 (FIG. 5) No. 7-8914 (No. 2)

  By the way, in the fitting structure of the pump shaft 113 and the pulley sheet 103, if rust preventive oil applied to the surface remains from the viewpoint of rust prevention of the pump shaft 113, the pump shaft 113 and the pulley sheet 103 are interposed between them. An oil film may remain and a sufficient fitting force may not be obtained. On the other hand, when the amount of oil that can be scraped off is increased by increasing the groove 118, there is a disadvantage that a sufficient fitting force may not be obtained due to a decrease in the contact area between the pump shaft 113 and the pulley sheet 103. .

  The present invention has been made in view of the above-described problems, and the object thereof is to ensure a sufficient fitting force when a ring body is press-fitted into a shaft body in which oil such as rust preventive oil remains. The object is to provide a coupling structure of a shaft and a ring.

  In order to achieve the above-described object, the coupling structure of the shaft body and the ring body according to the present invention is a coupling structure of the shaft body and the ring body that press-fits the shaft body and the ring body in which oil remains in the fitting portion. And the recessed part which scrapes and accommodates the said oil at the time of press fit is provided in the outer surface of the said shaft body in the said fitting part, and the ratio for which the said recessed part accounts with respect to the outer periphery of the said shaft body will be 20-40%. It is characterized by doing so.

  In the coupling structure of the shaft body and the ring body configured as described above, when the shaft body is press-fitted into the ring body, the concave portion provided on the outer surface of the shaft body remains in the fitting portion between the shaft body and the ring body. Scrape and store the oil. At this time, in order to obtain a sufficient fitting force, it is necessary to ensure a certain contact area or more in the fitting portion between the shaft body and the ring body. 40%. Thereby, when the shaft body is smoothly press-fitted into the ring body, a sufficient fitting force can be ensured and the pulling-out force can be improved.

  Moreover, the coupling structure of the shaft and ring according to the present invention is characterized in that the ring is a rotating member mounting sheet.

  In the coupling structure of the shaft body and the ring body configured as described above, since the rotating member mounting sheet can be securely attached to the shaft body, for example, a rotating member such as a pulley can be attached to the shaft body with a sufficient fitting force. Can be installed.

  According to the present invention, it is possible to solve the problem that a sufficient fitting force as in the conventional case cannot be obtained, and a sufficient fitting is achieved when the ring body is press-fitted into the shaft body in which oil such as rust preventive oil remains. A resultant force can be secured.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a partially sectional front view showing a bearing device as an embodiment of a coupling structure of a shaft body and an annular body according to the present invention, and FIGS. 2A to 2C are sectional views illustrating sectional shapes of recesses. 3 is a graph showing the relationship between the ratio of the recess to the outer periphery of the pump shaft and the fitting force, and FIG. 4 is a graph showing the relationship of each element in the relationship between the ratio of the recess to the outer periphery of the pump shaft and the fitting force. In addition, the same code | symbol is attached | subjected to the member which is common in each part of the water pump 100 (refer FIG. 6) in the prior art mentioned above, and the overlapping description is abbreviate | omitted.

FIG. 1 shows a bearing device 10 used in a water pump 100 (see FIG. 5) as a coupling structure of a shaft body and an annular body. The bearing device 10 includes a pump shaft 20 as a shaft body that constitutes an inner ring, and a long cylindrical outer ring 30. Between one end of the outer ring 30 (right end in FIG. 1) and the pump shaft 20, balls 32 are rotatably held by the cage 31 at equal intervals in the circumferential direction. Further, between the other end (the left end in FIG. 1) of the outer ring 30 and the pump shaft 20, a cylindrical roller 34 is rotatably held by a cage 33 at equal intervals in the circumferential direction. Therefore, the pump shaft 20 is supported by the outer ring 30 so as to be relatively smoothly rotatable.
As described above, in addition to the structure in which one is provided with the ball 32 and the other is provided with the cylindrical roller 34, both may use the ball 32, or both may use the cylindrical roller 34.

  Usually, oil such as rust preventive oil remains on the outer surface 20a of the pump shaft 20 which is the fitting portion 21 formed between the pulley sheet 103 (see FIG. 6) as an annulus. For this reason, the remaining oil is scraped at the time of press-fitting, and in order to accommodate the scraped oil, the recesses 22 having a width W (see FIG. 2) extended in the axial direction are arranged at predetermined intervals over the entire circumference. A plurality are provided.

  2A to 2C illustrate the cross-sectional shape of the recess 22. The concave portion 22 shown in FIG. 2A is a V-shaped groove having an angle θ, and the bottom portion is an arc 22 a having a radius R. 2B is a V-shaped groove having an angle θ, and has a flat bottom portion 22b. A recess 22 shown in FIG. 2C is a V-shaped groove having an angle θ and has an arc-shaped bottom 22c having a radius R. Although any cross-sectional shape can be applied, the shoulder portion 23 of the recess 22 is preferably shaped to have an edge in order to scrape the oil remaining between the pump shaft 20 and the pulley sheet 103. Moreover, it is set as the shape and dimension which have a cross-sectional area which can accommodate all the oil scraped off.

  FIG. 3 shows the relationship between the ratio of the recess 22 (width W) to the outer periphery of the pump shaft 20 at the position AA in FIG. 1 as the fitting portion 21 and the fitting force obtained by press-fitting. FIG. 4 shows the relationship between the contact area between the pump shaft 20 and the pulley sheet 103 and the fitting force in the fitting portion 21 and the relationship between the amount of remaining rust preventive oil and the fitting force.

  That is, when the ratio of the recesses 22 is in the range of 10% to 20%, the amount of oil that can be scraped and accommodated increases as the ratio of the recesses 22 increases. The effect of increasing the degree of adhesion between the shaft 20 and the pulley sheet 103 is large, and the fitting force increases. Moreover, between 20 and 40%, the effect of increasing the amount of oil scraped and accommodated is balanced with the effect of decreasing the contact area due to the increase in the proportion of the recesses 22, so the fitting force is substantially constant. And when it exceeded 40%, the influence of the reduction | decrease of the contact area accompanying the increase in the recessed part 22 became large, and it turned out that fitting force falls. For this reason, the ratio occupied by the recesses 22 is set to be 20 to 40% with respect to the outer periphery of the pump shaft 20.

  As described above, according to the coupling structure of the shaft body and the annular body described above, the pump shaft 20 and the pulley sheet 103 that are reduced by the increase in the amount of residual oil that can be scraped and accommodated in the fitting portion 21 and the formation of the recess 22. Balance with the reduction of the contact area can be achieved, and the increase of the fitting force can be achieved.

In addition, the coupling structure of the shaft body and the ring body of the present invention is not limited to the above-described embodiment, and appropriate modifications and improvements can be made.
For example, in the above-described embodiment, the bearing device 10 used for the water pump is exemplified as the coupling structure of the shaft body and the ring body, but the present invention can also be applied to other bearing devices.

In the above-described embodiment, the case where the recess 22 is provided in parallel to the axial direction has been described. However, it is also possible to provide the recess 22 in parallel by being inclined in the axial direction.
Furthermore, the cross-sectional shape of the recess 22 shown in the above-described embodiment is an example, and the present invention is not limited to this.
In the above-described embodiment, the structure using the pulley sheet has been exemplified. However, the present invention can also be applied to a pulley direct connection structure that does not use the pulley sheet.

It is a front view of the partial cross section which shows the bearing apparatus as embodiment of the coupling | bonding structure of the shaft body and ring body which concerns on this invention. (A)-(C) are sectional drawings which illustrate the cross-sectional shape of a recessed part. It is a graph which shows the relationship between the ratio of the recessed part with respect to the outer periphery of a pump shaft, and fitting force. It is a graph which shows the relationship of each element in the relationship between the ratio of the recessed part with respect to the outer periphery of a pump shaft, and fitting force. It is sectional drawing which shows the connection structure of the conventional shaft and ring. It is sectional drawing which shows the water pump to which the conventional bearing apparatus which is a coupling structure of a shaft body and an annular body is applied. It is sectional drawing which shows the bearing apparatus as a conventional coupling structure of a shaft body and an annular body.

Explanation of symbols

10 Bearing device (Shaft and ring joint structure)
20 Pump shaft (shaft body)
20a outer surface 21 fitting part 22 concave part 103 pulley sheet (annular body, sheet for attaching rotating member)

Claims (2)

A coupling structure of a shaft body and a ring body in which the shaft body and the ring body in which oil remains in the fitting portion is coupled by press-fitting,
A concave portion that accommodates the oil at the time of press-fitting is provided on the outer surface of the shaft body in the fitting portion, and the ratio of the concave portion to the outer periphery of the shaft body is 20 to 40%. The coupling structure of the shaft and ring.   The shaft and ring coupling structure according to claim 1, wherein the ring is a rotating member mounting sheet.

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