JP2007270784A - Bearing for water pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing for a water pump capable of reducing manufacturing cost while maintaining basic functions of a bearing part by improving the structure of the bearing. <P>SOLUTION: A water pump shaft 11 comprises a straight shaft having the same outer diameter in the overall length, excluding chamfer parts at both ends. An outer ring 12 is fixed to an inner peripheral face of a housing part 4 of the water pump 1 in the press-fit state, outside in the middle of the water pump shaft 11. A plurality of needle rollers 13 are arranged in a single row between an inside raceway surface 12a formed on the outer ring 12 and an outside raceway surface 11a formed on the water pump shaft 11 opposing to the inside raceway surface 12a, and are held by a cylindrical cage 13a. Between the needle rollers 13 and an impeller 2 of the water pump 1 in the axial direction, a spiral spring washer 14 is fixed to the outer peripheral face of the water pump shaft 11 and the inner peripheral face of the housing part 4 in the press-fit state, so as to restrict axial movement of the needle rollers 13. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a bearing for a water pump.

  Usually, in a water pump for circulating the cooling water of a water-cooled engine for automobiles or the like, the rotating shaft of the pulley driven by the water-cooled engine and the rotating shaft of the impeller are a single water pump shaft that also serves as the inner ring of the bearing portion. (Refer to Patent Document 1). The water pump shaft may be formed in a stepped manner in order to meet the product standard of a mechanical seal for sealing the water pump shaft and the housing portion. Moreover, since the rolling element of a bearing part is the combination of a ball and a cylindrical roller, the groove | channel for forming the track surface (inner track surface) of a ball | bowl is required. As a result, the water pump shaft is partially formed into a stepped shaft having a different outer diameter. Further, since the rolling elements are a combination of balls and cylindrical rollers, the outer ring that supports them is inevitably formed in a solid form that cuts pipe material or the like.

JP-A-11-153096

  Therefore, to harden hard bars such as carburized steel (for example, SUJ2: high carbon chrome bearing steel) to make a stepped water pump shaft, or to cut a pipe material of the same material to make a solid outer ring. However, the manufacturing cost tends to increase. In addition, when these water pump shafts and solid outer rings are polished after heat treatment, accurate centering of each surface is required, which tends to further increase manufacturing costs.

  The subject of this invention is providing the bearing for water pumps which can aim at reduction of manufacturing cost, maintaining the basic function of a bearing part by devising the structure of a bearing part.

Means for Solving the Problems and Effects of the Invention

In order to solve the above problems, a bearing for a water pump according to the present invention is:
A water pump shaft that circulates cooling water of the water-cooled engine on one end side is fixed, and a water pump shaft that has a pulley driven by the water-cooled engine fixed on the other end side;
An outer ring fixed in a press-fitted state to the inner peripheral surface of the housing portion of the water pump on the outside of the midway portion in the axial direction of the water pump shaft;
A single row of needle rollers disposed between an inner raceway surface formed on the outer ring and an outer raceway surface formed on the water pump shaft facing the inner raceway surface;
Between the needle roller and the impeller in the axial direction, an annular restricting means that is fixed in at least the outer peripheral surface of the water pump shaft in a press-fit state and restricts movement of the needle roller in the axial direction,
A needle bearing portion is formed including the water pump shaft, an outer ring, and needle rollers, and the restriction means positions the needle bearing portion in the axial direction with respect to the housing portion.

  In this way, the movement in the axial direction of the single-row needle rollers is restricted from the shaft side (inner ring side) by the restriction means (for example, washer) that is press-fitted and fixed to the water pump shaft, and the inner periphery of the housing portion. By fixing the outer ring to the surface in a press-fit state, the movement of the needle rollers in the radial direction and the axial direction is suppressed from the outer ring side. Therefore, it is possible to easily configure the needle bearing portion by using the three components of the water pump shaft, the outer ring, and the single-row needle rollers, and to position them mutually.

  Also, by using a single row of needle rollers, the water pump shaft can be configured with a straight bearing portion with almost no step, and the outer ring is configured with a shell shape that is a pressed product of a thin steel plate. Is also possible. Therefore, the outer cost of the water pump shaft can be cut in one pass, and the outer surface can be polished in a centerless manner, thereby reducing the manufacturing cost.

  At that time, the outer ring is formed with an impeller side flange extending in an annular shape from one axial end side in the radial direction toward the inner side in the radial direction, and the outer ring is fixed to the housing portion in a press-fitted state and the impeller side flange is regulated. The needle bearing portion can be positioned and fixed with respect to the housing portion in the radial direction and the axial direction. Thus, when the outer ring is configured in a shell shape, the impeller side flange can be used as a positioning means (in the axial direction), and the needle bearing part can be easily assembled by synergistic action with the regulating means.

  Specifically, an annular mechanical seal is incorporated between the impeller in the axial direction and the restricting means to seal the water pump shaft and the housing part at one end in the axial direction. Both the outer peripheral surface of the housing and the inner peripheral surface of the housing portion are fixed in a press-fitted state, and contact with the mechanical seal at one end in the axial direction, and contact with the impeller side flange at the other end in the axial direction. It is desirable to restrict the movement of the needle rollers in the axial direction.

  According to this, the regulating means (for example, a spiral spring washer) is fixed to the water pump shaft and the housing portion in a press-fitted state. The fixing position of the restricting means is substantially determined by the mechanical seal for preventing water from entering from the pump side and the impeller side flange of the shell-shaped outer ring. Therefore, the positioning and fixing of the restricting means can be performed more easily in the assembly of the needle bearing portion.

  Further, the outer ring is formed with a pulley side collar portion that extends in an annular shape from the other end side in the axial direction toward the inside in the radial direction, and the axial direction is between the pulley side collar portion and the needle roller in the axial direction. An annular seal member can be arranged to seal the water pump shaft and the housing portion at the other end in the direction. In this way, by forming the pulley side flange on the shell-shaped outer ring and using the pulley side flange to arrange the pulley-side seal member, it is possible to prevent intrusion of water or the like from the outside with a simple structure. Can do.

  As a result, the water pump shaft can be formed with the same outer diameter at least from the outer raceway surface to the impeller mounting surface. Thus, it is easy to form the entire length of the water pump shaft as a straight shaft having the same outer diameter, and the above-described outer surface cutting and outer surface polishing can be performed efficiently, so that the manufacturing cost can be further reduced. In addition, also about a housing part, the part from the attachment surface of an outer ring to the attachment surface of a mechanical seal can be formed in the same internal diameter.

(Example)
Hereinafter, embodiments of the present invention will be described with reference to examples shown in the drawings. 1 is a cross-sectional view of a main part of a water pump including a water pump bearing according to the present invention, FIG. 2 is a partially enlarged cross-sectional view thereof, and FIG. 3 is an exploded perspective view of a main part of a needle bearing part. In FIG. 1, an impeller 2 of a water pump 1 that circulates cooling water of a water-cooled engine (not shown) is fixed to one end side (inner side) of a water pump shaft 11 and is driven by a water-cooled engine via a belt B. The pulley 3 is fixed to the other end side (outer side) of the water pump shaft 11. The water pump shaft 11 is pivotally supported by a water pump bearing 10 constituted by a needle bearing portion.

  As shown in FIGS. 2 and 3, the needle bearing portion 10 includes a water pump shaft 11 also serving as an inner ring, an outer ring 12 fixed to the housing portion 4 of the water pump 1, and the water pump shaft 11 and the outer ring 12. And needle rollers 13 arranged in a single row.

  The water pump shaft 11 is composed of a straight shaft having the same outer diameter over almost the entire length except for chamfered portions at both ends. Further, the outer ring 12 is fixed to the inner peripheral surface of the housing part 4 of the water pump 1 in a press-fitted state outside the middle part of the water pump shaft 11. Further, a plurality of (for example, eight) needle rollers 13 are arranged in a single row between the inner raceway surface 12a formed on the outer ring 12 and the outer raceway surface 11a formed on the water pump shaft 11 so as to be opposed thereto. It is supported by a cylindrical cage 13a. And between the needle roller 13 and the impeller 2 of the water pump 1 in the axial direction, a spiral spring washer 14 (annular regulating means) is provided between the outer peripheral surface of the water pump shaft 11 and the inner peripheral surface of the housing part 4. The needle rollers 13 are fixed in a press-fitted state and restrict the movement of the needle rollers 13 in the axial direction.

  Specifically, the outer ring 12 is formed in a shell shape obtained by pressing a thin steel plate. Further, the outer ring 12 is formed with an impeller side collar 12b (inner side collar) and a pulley side collar 12c (outer side collar) extending annularly from both axial ends toward the radial inner side. Has been. Thus, the outer ring 12 is fixed to the housing part 4 in a press-fit state, and the impeller side flange part 12b contacts (contacts) the spring washer 14, so that the needle bearing part 10 is in the radial direction and axial with respect to the housing part 4. Positioned and fixed in the direction.

  By the way, an annular mechanical seal 15 is incorporated between the impeller 2 and the spring washer 14 in the axial direction in order to seal the water pump shaft 11 and the housing part 4 on one end side in the axial direction. The spring washer 14 is in contact with the mechanical seal 15 at one end in the axial direction, and is in contact with the impeller side flange 12b at the other end in the axial direction to restrict the movement of the needle rollers 13 in the axial direction.

  Further, an annular seal member 16 is provided between the pulley-side flange portion 12c in the axial direction and the cage 13a of the needle roller 13 in order to seal the water pump shaft 11 and the housing portion 4 on the other end side in the axial direction. Is arranged.

  By configuring as described above, the water pump shaft 11 is formed with the same outer diameter at least from the outer raceway surface 11a to the mounting surface of the impeller 2. Further, the housing part 4 has at least the same inner diameter from the attachment surface of the outer ring 12 to the attachment surface of the mechanical seal 15.

  Therefore, at the time of manufacturing the water pump shaft 11, for example, a carburized steel (for example, SUJ2: high carbon chromium bearing steel) rod may be externally cut with a single pass, and after heat treatment, the centerless outer surface may be polished. Reduction can be achieved.

  Further, the spring washer 14 is in contact with the mechanical seal 15 and the impeller side flange 12b, and can regulate the movement of the needle roller 13 in the axial direction.

Therefore, when the needle bearing portion 10 is assembled, the water pump shaft 11 on which the impeller 2 and the mechanical seal 15 are mounted is supported on the housing portion 4. The spring washer 14 is press-fitted from the other end side (pulley side) of the needle bearing portion 10, and is positioned and fixed by the spring washer 14 and the mechanical seal 15.
The outer ring 12 in which the needle roller 13, the cage 13 a, and the seal member 16 are housed is press-fitted into the housing portion 4 and is positioned and fixed by the impeller side flange 12 b and the spring washer 14. Thereafter, the pulley 3 is fixed to the shaft end of the water pump shaft 11 to complete the setting of the water pump bearing 10 (needle bearing portion).

  Furthermore, since the engaging portion with the belt B is offset (polymerized in the radial direction) on the outside of the housing portion 4, the water pump 1 and the water pump bearing 10 can be configured more compactly and compactly.

  Reference numeral 4 a is a drain hole formed in the housing portion 4 so as to discharge cooling water leaked from the mechanical seal 15 to the outside. Further, the pulley 3 and the water pump shaft 11 are fixed by means usually used such as a thread portion and a retaining ring.

The principal part sectional drawing of a water pump provided with the bearing for water pumps which concerns on this invention. The partial expanded sectional view of FIG. FIG. 3 is an exploded perspective view of a main part of the needle bearing portion of FIG. 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Water pump 2 Impeller 3 Pulley 4 Housing part 10 Needle bearing part (water pump bearing)
11 water pump shaft 11a outer raceway surface 12 outer ring 12a inner raceway surface 12b impeller side collar (inner side collar)
12c Pulley side collar (outer side collar)
13 Needle roller 13a Cage 14 Spring washer (regulation means)
15 Mechanical seal 16 Seal member B Belt

Claims (5)

A water pump shaft that circulates cooling water of the water-cooled engine on one end side is fixed, and a water pump shaft that has a pulley driven by the water-cooled engine fixed on the other end side;
An outer ring fixed in a press-fitted state to the inner peripheral surface of the housing portion of the water pump on the outside of the midway portion in the axial direction of the water pump shaft;
A single row of needle rollers disposed between an inner raceway surface formed on the outer ring and an outer raceway surface formed on the water pump shaft facing the inner raceway surface;
Between the needle roller and the impeller in the axial direction, an annular restricting means that is fixed in at least the outer peripheral surface of the water pump shaft in a press-fit state and restricts movement of the needle roller in the axial direction,
A water pump including a water pump shaft, an outer ring, and needle rollers, wherein a needle bearing portion is formed, and positioning of the needle bearing portion with respect to the housing portion in the axial direction is performed by the restricting means. Bearings. The outer ring is formed with an impeller side flange extending annularly from the one end side in the axial direction toward the inside in the radial direction,
The outer ring is fixed to the housing part in a press-fit state, and the impeller side flange comes into contact with the restricting means so that the needle bearing part is positioned and fixed with respect to the housing part in a radial direction and an axial direction. The water pump bearing according to claim 1. Between the impeller and the regulating means in the axial direction, an annular mechanical seal is incorporated to seal the water pump shaft and the housing part at one end in the axial direction.
The restricting means is fixed to the outer peripheral surface of the water pump shaft and the inner peripheral surface of the housing portion in a press-fit state, and contacts the mechanical seal on one end side in the axial direction, while the other end in the axial direction. The bearing for water pumps of Claim 2 which contact | abuts the said impeller side collar part on the side and restrict | limits the movement of the said needle roller in the axial direction. The outer ring is formed with a pulley side flange extending in an annular shape from the other end side in the axial direction toward the inside in the radial direction,
An annular seal member is disposed between the pulley-side flange portion and the needle roller in the axial direction so as to seal the water pump shaft and the housing portion on the other end side in the axial direction. The bearing for water pumps of any one of thru | or 3.   5. The water pump bearing according to claim 1, wherein at least a portion from the outer raceway surface to a mounting surface of the impeller is formed to have the same outer diameter.

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