JP2003343551A - Bearing for water pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing for a water pump which is light in weight, easily processed and inexpensively manufactured without damaging reliability as a bearing. <P>SOLUTION: A thin shaft 12 is integrally formed with a thick shaft 11 by forming two raceway grooves 11y, 11y at a prescribed position on the outer peripheral face 11x of the thick shaft 11 of a rotary shaft 1 by applying component rolling to a pipe material, and at the same time, by injection-molding a resin material 12a to a required site of the inner peripheral face 11a of the thick shaft containing inner face swelling parts 11b, 11b on the rear side of the raceway grooves 11y. The rotary shaft 1 is easily manufactured to be light in weight compared with a conventional rotary shaft using a solid bar steel material by this composition. Also, since the thin shaft 12 of the rotary shaft 1 is formed continuously from the site containing the inner face swelling parts 11b of the thick shaft 11, falling-out in the axial direction of the thin shaft 12 is prevented, and strength and durability or the like as the bearing of the thick shaft 12 are made equal to the conventional one by the reinforcement of the resin material 12a. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water pump bearing, and more particularly to a water pump bearing which can be manufactured at a low weight and cost by using a resin material for a part of a rotary shaft.

[0002]

2. Description of the Related Art Conventionally, in a bearing device for a water pump (water pump) mounted on a vehicle or the like, there is provided a solid rotary shaft having a thick shaft portion and a thin shaft portion, and a thick shaft of the rotary shaft. A rolling device having an outer ring externally inserted into the shaft part and fixed to the housing, and rolling elements arranged between raceways formed on the outer peripheral surface of the thick shaft part and the inner peripheral surface of the outer ring facing the thick shaft part, respectively. A bearing unit is used.

FIG. 2 is a partial cross-sectional view showing the structure of a conventional water pump bearing. This water pump bearing has a thick shaft portion 1
1 and a thin shaft portion 12, an outer ring 2 arranged around the thick shaft portion 11, and a plurality of rolling elements 3, 3 arranged between the thick shaft portion 11 and the outer ring 2. ... and have. The rotating shaft 1 is formed with a large-diameter thick shaft portion 11 and a small-diameter thin shaft portion 12 by turning using bearing steel.
Further, two raceway grooves 11y and 11y are formed at predetermined positions on the outer peripheral surface 11x of the thick shaft portion 11 of the rotary shaft 1, and two inner races 2x of the outer race 2 facing these raceway grooves 11y are also similarly formed. The raceway grooves 2y are formed, and a plurality of rolling elements 3 are fitted between these raceway grooves. The outer peripheral surface 11x of the thick shaft portion and the inner peripheral surface 2 of the outer ring facing each other
The annular space of the bearing formed by x and x is a seal member 4 disposed at both ends of the outer ring 2 for retaining the lubricating oil and waterproofing.
It is sealed by a and 4b. At the outer end (left side in the drawing) of the thick shaft portion 11, an input pulley or the like connected to an engine or the like is attached, and the other thin shaft portion 12 is provided.
The outer end (right side in the drawing) of the is placed in the water pump via a mechanical seal or the like, and the impeller is attached.

[0004]

By the way, in the conventional water pump bearing as described above, since the rotary shaft is manufactured by using the bearing steel material or the like, there is a problem that the weight becomes heavy. It was

Further, since the thick shaft portion and the thin shaft portion of the rotary shaft are integrally formed, it is difficult to perform machining such as turning and polishing, and the same bearing steel material as the thick shaft portion is used for the thin shaft portion. Therefore, when performing the required rustproofing treatment on the thin shaft portion, it is necessary to mask the raceway groove portion of the thick shaft portion, which causes a problem that the processing cost becomes high.

[0006] Therefore, in order to realize the weight reduction and the cost reduction of the rotary shaft, a large number of proposals for making the thick shaft portion hollow, and the entire rotary shaft as a hollow integrated body such as Japanese Patent Laid-Open No. 2000-65070. Has been proposed. Further, the present applicants have also disclosed in Japanese Patent Laid-Open No. 9-25818 that water formed by molding a synthetic resin around a support core rod fixed to the end of the thick shaft portion with a thin shaft portion of a rotary shaft. We are making proposals for bearings for pumps.

However, under the present circumstances where it is required to reduce the weight of vehicles equipped with this water pump and further reduce the cost, it cannot be said that these proposals have still solved the problem, and it is considered that more water is used. There is a demand for weight reduction and cost reduction of bearings for pumps.

The present invention has been made in order to solve the above-mentioned problems, and provides a bearing for a water pump which is lightweight and easy to process, and which can be manufactured at a low cost without impairing the reliability of the bearing. It is intended to be provided.

[0009]

In order to achieve the above object, the invention as set forth in claim 1 is directed to a rotary shaft comprising a thick shaft portion and a thin shaft portion, and the circumference of the thick shaft portion of the rotary shaft. In a water pump bearing comprising an outer ring arranged in, and a plurality of rolling elements arranged between raceway grooves formed in each of the thick shaft portion and the outer ring, the thick shaft portion of the rotary shaft is hollow. At least one inner surface bulging portion is formed on the inner peripheral surface of the thick shaft portion, and the thin shaft portion has a resin material on the inner peripheral surface of the thick shaft portion including the inner surface bulging portion. Fill the
The resin material is formed by axially extending from one end opening of the thick shaft portion.

According to the present invention, in the bearing for a water pump, the thick shaft portion where the raceway groove is formed is hollow, and the thin shaft portion of the rotary shaft that does not affect the bearing life is formed of a resin material by injection molding or the like. By doing so, the intended purpose is achieved.

That is, according to the first aspect of the present invention, by making the thick shaft portion of the rotary shaft hollow, the thick shaft portion can be manufactured by rolling using a pipe material. This makes it possible to easily manufacture a lightweight rotating shaft as compared with the conventional thick shaft portion. Further, since the resin material to be the thin shaft portion is filled in the inner peripheral surface including the inner surface bulging portion formed on the inner surface of the thick shaft portion, the thin shaft portion is prevented from coming off in the axial direction, In addition, the effect of reinforcing the thick shaft portion from the inner surface can be obtained. Further, since the thin shaft portion of the rotary shaft is made of the resin material, it is not necessary to perform rust prevention treatment or the like.

Here, the water pump bearing of the present invention preferably has a structure in which the inner surface bulging portion is formed at an inner surface side portion of a raceway groove formed in the thick shaft portion (claim 2). Can be adopted.

According to the second aspect of the present invention, by using a rolling process or the like to form the raceway groove of the thick shaft portion, the inner surface bulging portion of the inner peripheral surface and the raceway groove of the outer peripheral surface are formed. Since they can be formed at the same time, it is possible to save the labor at the time of processing.

In addition, by using the same standard for the thick shaft member, compared to the conventional solid solid product which is uniform in one product, the size, such as the length and diameter of the thin shaft portion, which is different for each product type, can be changed. It is also possible to obtain an effect that it becomes possible to easily cope with the situation.

With the structure of such a rotating shaft,
It becomes possible to achieve weight reduction and cost reduction of the entire water pump bearing.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a partial cross-sectional view showing the structure of a water pump bearing according to an embodiment of the present invention. The bearing for the water pump in the present embodiment also has
The structure basically has the same basic structure as the conventional example, two raceway grooves are formed on the outer peripheral surface of the rotating shaft, and balls are used as rolling elements. Moreover, the same code | symbol is attached | subjected to the structural member which has the same function as a prior art example.

This water pump bearing also includes a rotating shaft 1 having a thick shaft portion 11 and a thin shaft portion 12, an outer ring 2 arranged around the thick shaft portion 11, and a thick shaft portion 11 and the outer ring 2. And a plurality of rolling elements 3, 3, ... In this rotary shaft 1, a pipe material using a bearing steel material or the like is used for the thick shaft portion 11, and two raceway grooves 11y, 11y are formed at predetermined positions on the outer peripheral surface 11x by rolling, and The inner peripheral surface 11a side, which is the back side of the raceway groove 11y, corresponds to the raceway groove 11 by the rolling.
Two inner surface bulges 11b and 11b are formed. In addition, the thick shaft portion inner peripheral surface 11a extending from these inner surface bulging portions 11b and 11b to one end opening (right side in the drawing) of the thick shaft portion 11
A resin material 12a having heat resistance, such as a phenol resin, is continuously filled in the predetermined portion of the thin shaft portion 12 by injection molding.

As in the conventional example, these thick shaft portions 11 are
Inner peripheral surface 2x of the outer ring 2 facing the raceway grooves 11y, 11y
Similarly, two raceway grooves 2y, 2y are similarly formed, and a plurality of rolling elements 3 are provided between the thick shaft portion 11 and the raceway groove of the outer ring 2.
Is inserted. The annular space of the bearing formed by the outer peripheral surface 11x of the large shaft portion and the inner peripheral surface 2x of the outer ring facing each other is a seal member 4a arranged at both ends of the outer ring 2 for retaining and waterproofing the lubricating oil. , 4b, and a pulley for input connected to an engine or the like is attached to the outer end portion (left side in the drawing) of the thick shaft portion 11, and the outer end portion (right side in the drawing) of the other thin shaft portion 12 is attached. One) is arranged in the water pump via a mechanical seal or the like, and the impeller is attached.

With this structure, in this water pump bearing, the thick shaft portion 11 of the rotary shaft 1 is formed of a hollow pipe material, and the thin shaft portion 12 is also formed of the resin material 12a. Compared to the conventional example using solid bar-shaped steel, it can be finished much lighter. Further, the thick shaft portion 11 is formed by rolling, and the thin shaft portion 12 is formed.
Also, since it can be formed integrally with the thick shaft portion 11 by injection molding, there is also an advantage that it can be easily manufactured as compared with the conventional example formed by turning or the like. Therefore, the water pump bearing according to the present embodiment can reduce the material cost and the processing cost.

Moreover, since the thin shaft portion 12 is formed continuously with the thick shaft portion inner peripheral surface 11a including the inner surface bulging portion 11b on the rear surface of the raceway groove 11y, the inner surface bulging portion 11b is formed. The resin material 12a reinforces the thick shaft portion 11 from the inner surface side while functioning as a retaining member in the axial direction of the portion 12.
The strength and durability of the bearing can be made equal to the conventional one.

The method of forming the thin shaft portion 12 made of a resin material is not limited to the injection molding, and a rod-shaped thin shaft portion having an outer diameter to be fitted to the inner diameter of the thick shaft portion 11 is previously prepared in another step. It is also possible to use a method in which it is formed and press-fitted into the thick shaft portion 11. However, during this press-fitting, there is a concern that the dimension of the raceway groove 11y may change depending on the hardness of the resin material. Therefore, it is preferable to use an injection molding method that can integrally form the thick shaft portion 11 and the thin shaft portion 12.

Further, the inner surface bulging portion 11 of the inner surface 11a of the thick shaft portion
Although b also shows an example in which the outer peripheral surface 11x is formed at a position corresponding to the inner surface side of the raceway groove 11y, the formation position of the inner surface bulging portion 11b is not particularly limited, and it can be used as a rolling element. In the case of a rolling bearing such as a cylindrical roller bearing in which the bulging portion is not formed on the back side of the raceway surface, the inner surface bulging portion may be separately formed at an arbitrary position within the range where the resin member is injection molded. .

Furthermore, the portion filled with the resin material 12a is not limited to this example, and the thick shaft portion inner surface 11a up to the outer end portion (left side in the drawing) of the thick shaft portion 11 to which an input pulley or the like is attached. It goes without saying that the whole may be filled.

[0024]

As described in detail above, according to the water pump bearing of the present invention, the thick shaft portion of the rotary shaft is formed in a hollow shape, and the thin shaft portion is formed of the resin material. Compared with the conventional example using the rod-shaped steel material, it can be manufactured lighter and easier, and the material cost and the processing cost of the entire bearing can be reduced.

Further, since the thin shaft portion of the rotary shaft is continuously formed on the inner peripheral surface of the thick shaft portion including the inner surface bulging portion on the rear surface of the raceway groove portion of the thick shaft portion, the inner surface bulging portion is formed. The thin shaft portion functions as a stopper in the axial direction, and the resin material reinforces the thick shaft portion from the inner surface side, so that the strength and durability of the bearing can be made equal to those of the conventional one.

Further, the thin shaft portion of the rotary shaft does not need to be rust-proofed, and when the thick shaft portion is standardized to be a common member, the rotation of the conventional solid solid product is uniform. Compared with the shaft, it is possible to easily deal with a size change such as a length and a diameter of the thin shaft portion which is different for each type.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view showing a structure of a water pump bearing according to an embodiment of the present invention.

FIG. 2 is a partial cross-sectional view showing the structure of a conventional water pump bearing.

[Explanation of symbols]

1 rotation axis 2 outer ring 2x inner surface 2y track groove 3 rolling elements 4a, 4b seal member 11 thick shaft 11a inner peripheral surface 11b Internal bulge 11x outer peripheral surface 11y orbital groove 12 Thin shaft 12a Resin material

Claims (2)

[Claims] 1. A rotary shaft including a thick shaft portion and a thin shaft portion, an outer ring arranged around the thick shaft portion of the rotary shaft, and raceway grooves formed in each of the thick shaft portion and the outer ring. In a bearing for a water pump including a plurality of rolling elements arranged in a plurality of rolling elements, a thick shaft portion of the rotary shaft is formed in a hollow shape, and at least one inner surface bulging portion is formed on an inner peripheral surface of the thick shaft portion. Is formed, the thin shaft portion is filled with a resin material on the inner peripheral surface of the thick shaft portion including the inner surface bulging portion, and the resin material is axially fed from one end opening of the thick shaft portion. A bearing for a water pump, which is formed by extending. 2. The bearing for a water pump according to claim 1, wherein the inner surface bulging portion is formed at an inner surface side portion of a raceway groove formed in the thick shaft portion.