JPH11257286A - Water pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the durability of a sliding bearing and secure the smooth rotation of a rotor by arranging a clearance between the sliding surfaces of the sliding bearing and a rotary shaft in a manner that both end parts in the axial line direction of the rotary shaft are set larger than a central part. SOLUTION: A sliding bearing part 2A is formed on a pump body part 2, and the intermediate part of a rotary shaft 5 is rotatively journalled. A vane 8 is attached to the inside of the pump chamber R formed at one end of the rotary shaft 5. A clearance in the sliding surface 2D part of the sliding bearing part 2A and rotary shaft 5 is so arranged that both end parts in the axial line direction of the rotary shaft 5 are set larger than a central part, the outside diameters of both end parts of the sliding surface are gradually contracted from the center part, and the sliding surface is formed into a barrel shape. Hereby, increase of bearing pressure in both end parts of the sliding bearing 2A can be avoided, the durability of the sliding bearing 2A is improved, and the smooth rotation of the rotary shaft 5 can be secured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water pump, and more particularly to a water pump suitable for circulating cooling water for an internal combustion engine of an automobile or the like.

[0002]

2. Description of the Related Art Conventionally, as this type of water pump, for example, the one described in Japanese Utility Model Laid-Open No. 63-190519 has been known.

In such a water pump, a rotary shaft is rotatably supported by a pump body by a slide bearing, and an impeller located in a pump chamber of the pump body is attached to one end of the rotary shaft. A driven pulley as a driven rotating body located outside the pump body is attached to the other end of the shaft. The clearance between the sliding surfaces of the rotating shaft and the slide bearing is set to be constant in the axial direction of the rotating shaft. That is, the sliding surface on the rotating shaft side is formed as an outer peripheral surface having a uniform outer diameter extending in the axial direction, and similarly, the sliding surface on the sliding bearing side is uniformly formed in the axial direction of the rotating shaft. It is formed as an inner peripheral surface of the inner diameter, and a certain clearance is formed between these sliding surfaces in the axial direction of the rotating shaft.

[0004]

When such a water pump is driven, that is, when the driven pulley is driven to rotate via a belt, the influence of the load applied to the rotating shaft from the driven pulley and the impeller is reduced. receive. In other words, belt tension or the like is applied to the driven pulley so as to decenter the other end of the rotary shaft, and a load is applied to the impeller to decenter the one end of the rotary shaft.

However, in the above-mentioned conventional water pump, both ends of the sliding surface of the rotating shaft are particularly strongly pressed against the sliding surface of the sliding bearing due to the eccentric load applied to the rotating shaft. In some cases, the surface pressure between the sliding surfaces was extremely increased. As a result,
There is a problem that the durability of the slide bearing is impaired, and smooth rotation of the rotating shaft is hindered.

SUMMARY OF THE INVENTION It is an object of the present invention to reduce the influence of eccentric load applied to a rotating shaft, suppress a local increase in surface pressure between the sliding surfaces of the rotating shaft and the sliding bearing, and improve the durability of the sliding bearing. An object of the present invention is to provide a water pump capable of improving the rotation and ensuring smooth rotation of a rotating body.

[0007]

According to a first aspect of the present invention, an intermediate portion of a rotating shaft is rotatably supported by a slide bearing provided on a pump body, and one end of the rotating shaft is
In a water pump, wherein an impeller located in a pump chamber of the pump body is attached, and a driven rotor to which a rotational driving force is transmitted is attached to the other end of the rotating shaft, a slide between the sliding bearing and the rotating shaft is provided. The clearance between the moving surfaces is set so that both end portions in the axial direction of the rotation shaft are set larger than the center portion.

According to a second aspect of the present invention, in the first aspect, the sliding surface of the rotating shaft is such that the outer diameters of both end portions in the axial direction are gradually reduced from a central portion.

According to a third aspect of the present invention, in the first or second aspect, the sliding surface of the slide bearing is such that inner diameters of both end portions in the axial direction gradually increase from a central portion. .

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 and FIG. 2 are explanatory diagrams of a first embodiment of the present invention. This example is an application example as a water pump for circulating cooling water for an automobile engine.

In FIG. 1, 1 is a pump body,
The first and second body portions 2 and 3 are connected by bolts (not shown). Reference numeral 4 denotes an O-ring that seals between the body parts 2 and 3. A pump chamber R is formed in the pump body 1, and a slide bearing 2 </ b> A as a slide bearing is formed in the body 2. An intermediate portion of the rotary shaft 5 is rotatably supported by the slide bearing portion 2A. In addition, the sliding bearing 2A
Is formed with an oil supply hole 2B and an oil groove 2C, and lubricating oil from a hydraulic source such as an oil pump or lubricating oil dropped is supplied to the oil supply hole 2B. Oil supply hole 2
The lubricating oil from B is guided into the oil groove 2C, and lubricates between the sliding surfaces 2D and 5A between the sliding bearing 2A and the rotating shaft 5.
The sliding surfaces 2D and 5A will be described later.

The body 2 is provided with a mechanical seal 6 and an oil seal 7 for sealing between the body 2 and the rotating shaft 5. 2E is a drain hole opened to the atmosphere, and 2F is a drain hole for oil. At one end of the rotating shaft 5, a vane 8 located in the pump chamber R is attached.
A driven sprocket 9 as a driven rotating body is attached to the other end of the driven sprocket 9. The passive sprocket 9 is connected to a drive sprocket (not shown) via a chain.

Sliding surface 2 between sliding bearing 2A and rotating shaft 5
The clearance between D and 5A is set so that both end portions (left and right portions in FIG. 1) in the axial direction of the rotary shaft 5 are larger than the center portion. In the case of this example, as shown in FIG. 2, the outer diameters of both end portions (left and right portions in FIG. 2) of the sliding surface 5A of the rotating shaft 5 are gradually reduced from the central portion, and the sliding surface 5A Has a so-called barrel shape. For example, both ends in a range of a distance L1 (2 mm to 5 mm) from both ends of the sliding surface 5A have a radius H1 (0.02) higher than that of the center portion.
05 mm to 0.020 mm), and both ends and a central portion thereof have a radius R1 (500 m).
m to 1500 mm). The peripheral edges of both ends of the sliding surface 5A are rounded off.

Next, the operation will be described.

When the driven sprocket 9 is rotationally driven through a chain, the vane 8 rotates together with the rotating shaft 5, and after cooling water of the automobile engine is drawn into the pump chamber R from a suction port (not shown), It is discharged from a discharge port (not shown). As a result, the cooling water circulates between the engine and the radiator.

When the water pump is driven, a load is applied to the driven sprocket 9 so as to decenter the other end of the rotary shaft 5 due to the tension of a chain (not shown). Thus, a load or the like that eccentrically rotates one end of the rotating shaft 5 is applied. The rotating shaft 5 receiving such an eccentric load has a sliding surface 5A.
Of the sliding bearing portion 2A tends to be strongly pressed. However, as described above, the rotating shaft 5 is provided at both ends of the sliding bearing portion 2A.
Is set large, so that an increase in surface pressure at both end portions of the sliding bearing portion 2A is avoided. As a result, the durability of the sliding bearing portion 2A is improved, and smooth rotation of the rotating shaft 5 is ensured.

FIG. 3 is an explanatory diagram of a second embodiment of the present invention.

In the case of this embodiment, the inner diameter of both ends of the sliding surface 2D of the sliding bearing portion 2A is gradually reduced from the central portion, and the sliding surface 2D has a so-called drum shape. For example, a distance L2 (2 mm to 2 mm) from both ends of the sliding surface 2D.
5 mm) has a radius reduced by a height H2 (0.005 mm to 0.020 mm) from the center, and both ends and the center have a radius R2 (500 mm to 1500 mm). ) Smoothly continuous due to the arc surface. The peripheral edges of both end portions of the sliding surface 2D are rounded off.

In the case of the present embodiment, the sliding bearing 2
By making the sliding surface 2D of A a so-called drum shape,
As in the case of the above-described embodiment, both end portions of the clearance between the sliding surfaces 2D and 5A are set larger than the central portion. Therefore, similarly to the above-described embodiment, an increase in surface pressure at both end portions of the slide bearing portion 2A is avoided, durability of the slide bearing portion 2A is improved, and smooth rotation of the rotating shaft 5 is ensured. become.

(Others) As a combination of the first and second embodiments described above, the sliding surface 5A of the rotating shaft 5 has a so-called barrel shape, and the sliding surface 2D of the sliding bearing portion 2A has a so-called drum shape. Is also good. In short, it is only necessary that the clearance between both end portions between the sliding surfaces 2D and 5A can be set larger than the central portion. Further, depending on the degree of the eccentric load applied to the rotating shaft 5, at least one of the clearances at both end portions between the sliding surfaces 2D and 5A may be simply set to be larger than the central portion.

Further, the sliding surface 2D may be formed by a cylindrical sliding bearing separate from the pump body 1.
In addition to the driven sprocket 9 as the driven rotating body,
It may be a pulley around which a belt is wound, or a driven gear that meshes with a drive gear. In the case of a pulley, the tension of the belt is applied as an eccentric load of the rotating shaft 5.

[0023]

As described above, according to the first aspect of the present invention, the clearance at both ends between the sliding surfaces of the rotating shaft and the slide bearing is set to be larger than that at the central portion, so that the rotating shaft can be rotated. Reduce the effect of eccentric loads on both ends,
A local increase in surface pressure between the sliding surfaces of the rotating shaft and the sliding bearing can be suppressed, and as a result, the durability of the sliding bearing can be improved, and smooth rotation of the rotating shaft can be ensured.

According to a second aspect of the present invention, in the sliding surface of the rotating shaft, the outer diameter of both end portions is gradually reduced from the central portion, so that the sliding surface between the rotating shaft and the slide bearing is provided. The clearance at both ends between them can be set to be larger than that at the center.

According to a third aspect of the present invention, in the sliding surface of the sliding bearing, by gradually increasing the inner diameter of both end portions from the center portion, the sliding surface between the rotating shaft and the sliding bearing is formed. Can be set larger than the central portion.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part for explaining a first embodiment of the present invention.

FIG. 2 is an enlarged view of a rotation shaft of FIG.

FIG. 3 is an enlarged sectional view of a sliding bearing according to a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pump body 2, 3 Body part 2A Sliding bearing part (sliding bearing) 2D Sliding surface 5 Rotating shaft 5A Sliding surface 8 Vane 9 Driven sprocket (driven rotating body) R Pump room

Claims (3)

[Claims] An intermediate portion of a rotary shaft is rotatably supported by a slide bearing provided on a pump body, and an impeller located in a pump chamber of the pump body is attached to one end of the rotary shaft. In a water pump in which a driven rotary member to which a rotational driving force is transmitted is attached to the other end of the rotary shaft, a clearance between a sliding surface of the slide bearing and the rotary shaft is in an axial direction of the rotary shaft. Water pump characterized in that both ends are set larger than the center. 2. The water pump according to claim 1, wherein an outer diameter of both ends in the axial direction of the sliding surface of the rotating shaft is gradually reduced from a central portion. 3. The water pump according to claim 1, wherein the sliding surface of the sliding bearing has an inner diameter at both ends in the axial direction gradually increased from a central portion.