JP3801064B2 - Water pump - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a water pump, and more particularly to a water pump for automobiles.
[0002]
[Prior art]
A conventional water pump is disclosed in, for example, Japanese Patent Laid-Open No. 2-45698. As shown in FIG. 2, the water pump includes a pulley 41, a solid shaft portion 42 that is press-fitted into the pulley 41, and rotates integrally with the pulley 41, and is press-fitted into the shaft portion 42, and is integrated with the shaft portion 42. Is disposed between the outer periphery of the support portion and the inner periphery of the pulley 41, and rotates the pulley 41. The impeller 43 that rotates in rotation, the body 45 having the substantially cylindrical support portion 44 through which the shaft portion 42 is inserted, and the inner periphery of the pulley 41 are arranged. A bearing 46 that supports the bearing and a mechanical seal 47 that seals one end of the cylindrical space defined between the outer peripheral surface of the shaft portion 42 and the inner peripheral surface of the support portion are provided.
[0003]
By the way, in recent years, water pumps are required to simplify the assembly process and reduce the number of parts due to the need for cost reduction and weight reduction of parts.
[0004]
In the prior art as described above, the solid shaft portion 42 and the pulley 41 are separate from each other, and the solid shaft portion 42 and the pulley 41 are connected one by one at the time of assembly. It is not satisfactory in terms of conversion and assembly. In order to solve such a problem, it is conceivable to employ a structure in which a pulley and a bottomed hollow shaft portion are formed by pressing from a single plate material. In this way, the number of parts can be reduced and the weight can be reduced. The shaft portion can be formed by deep drawing, and the impeller side end portion of the shaft hollow chamber along the axial length direction is closed by the bottom wall portion.
[0005]
On the other hand, surface treatment such as plating and painting is performed on the pulley and the shaft portion in order to improve corrosion resistance so that rust or the like due to rainwater or humidity in the air does not occur.
[0006]
However, the surface treatment liquid such as the surface treatment plating solution or coating solution does not mix with the surface treatment liquid such as the surface treatment plating liquid or coating liquid inside the hollow shaft part that is deep-drawn, especially the tip part. There is a risk of problems such as this.
[0007]
[Problems to be solved by the invention]
Therefore, the present invention aims to reduce the number of parts and reduce the weight of the water pump, and to improve the corrosion resistance by sufficiently circulating the surface treatment liquid inside the deep-drawn hollow shaft portion. And
[0008]
[Means for Solving the Problems]
In order to solve the above technical problem, the technical means taken in the invention of claim 1 includes a pulley, a shaft portion that rotates integrally with the pulley, and an impeller that rotates integrally with the shaft portion. A body having a substantially cylindrical support portion through which the shaft portion is inserted, a bearing disposed between an outer periphery of the support portion and an inner periphery of the pulley, and rotatably supporting the pulley, In the water pump including a mechanical seal that seals one end of a cylindrical space defined between the outer peripheral surface of the shaft portion and the inner peripheral surface of the support portion, the pulley and the shaft portion are integrated. The shaft portion has a hollow shape, the pulley side end portion is open, the impeller side end portion is closed, and the side surface on the impeller side end portion side is radially inward of the shaft portion.・ Penetration outside Water pump is the number of through holes formed, the through hole is characterized in that it is closed by fitting the said shaft and said impeller.
[0009]
According to the above means, the pulley and the shaft portion are integrally formed, the shaft portion has a hollow shape, the pulley side end portion is opened, and the impeller side end portion is closed, thereby reducing the number of parts. And lighter weight. In addition, a plurality of through holes are formed in the side surface of the shaft portion on the side of the impeller side in the radial direction so that the surface treatment liquid can be reliably turned around inside the shaft portion. Since the through hole is closed by fitting the shaft and the impeller, water leakage through the through hole can be prevented.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
A first embodiment of the present invention will be described with reference to FIG.
[0011]
In FIG. 1, the body 12 of the water pump 10 is fixed to an engine cylinder block or the like (engine body) 90 via a gasket 80 or the like by means of fastening means not shown as is well known. The body 12 is formed with a stepped cylindrical portion (cylindrical support portion) having a large diameter portion 12a and a small diameter portion 12b on the proximal end (right end) side and the distal end (left end) side, respectively. An inner race of the bearing 14 is externally fitted and fixed on the small diameter portion 12b of the cylindrical portion. The right end surface of the inner race of the bearing 14 is adjacent to the large diameter portion 12 a of the body 12. There may be a gap between the right end surface of the inner race and the large diameter portion 12a.
[0012]
A pulley 20 is fitted on the outer race of the bearing 14 so as to be integrally rotatable. The pulley 20 is formed as an outer peripheral portion of the cylindrical cup-shaped rotating body 18 in the axial direction. Openings 22a for discharging water droplets leaked from the mechanical seal 50 to the outside are formed at equiangular intervals at the bottom 22 of the rotating body 18 that is continuous with the outer peripheral portion having a concave shape. In addition, a hollow (tubular) shaft portion 24 that extends in a direction away from the bottom portion 22 (right direction in FIG. 1) and that opens at the pulley 20 side end portion is integrally formed at the center of the bottom portion 22 of the rotating body 18. Molded. A bottom wall portion 25 is formed and closed at the distal end portion of the shaft portion 24, and a plurality of through holes 26 are formed at a position where the impeller 30 described later is fitted on the distal end portion side. In the present embodiment, two through holes 26 are formed. The rotating body 18 in which the pulley 20, the bottom portion 22, and the shaft portion 24 are integrated is press-molded from a steel plate so that the pulley 20 and the shaft portion 24 are concentric. Thereafter, the pulley 20, the bottom 22 and the shaft 24 are subjected to corrosion resistance treatment by plating or painting.
[0013]
An impeller 30 is fitted to the right end portion of the shaft portion 24 so as to be integrally rotatable so that the through hole 26 is closed. The impeller 30 is integrally formed with a base 30a, a plurality of blades 30b protruding from the right peripheral edge of the base 30a, and a hollow protrusion 30c protruding rightward from the center of the base 30a. By fitting the hollow protrusion 30c to the right end of the hollow shaft 24, the impeller 30 is fitted to the tip of the shaft 24 so as to be integrally rotatable. The impeller 30 may be subjected to corrosion resistance treatment after press forming a steel plate. The impeller 30 is disposed in a water chamber 95 formed inside the engine cylinder block 90 or the like and having an opening closed by the body 12. The water chamber 95 is a component of an engine coolant circuit (not shown).
[0014]
On one end side (boundary portion with the water chamber 95) of the cylindrical space 27 defined between the outer peripheral surface of the shaft portion 24 and the inner peripheral surfaces of the large-diameter portion 12a and the small-diameter portion 12b of the body 12, mechanical A seal 50 is provided to isolate the outside and the water chamber 95 in a watertight manner so that the cooling water does not leak to the outside. The mechanical seal 50 is fixed to the fixing ring 50a fixed to the inner peripheral side of the large-diameter portion 12a of the cylindrical portion of the body 12 and the shaft portion 24 so as to be relatively rotatable with respect to the fixing ring 50a and always establishes a liquid-tight relationship. And a rotating ring 50b in contact with each other as much as possible.
[0015]
Next, the operation of the first embodiment will be described.
[0016]
Through the belt 85 engaged with the belt engaging surface 20b of the pulley 20, the pulley 20 is rotated by the rotational force transmitted from the output shaft of the engine (not shown). As the pulley 20 rotates, the shaft portion 24 integrally formed with the pulley 20 also rotates in the same direction. Then, the impeller 30 integrated with the shaft portion 24 rotates in the water chamber 95 closed by the body 12.
[0017]
Now, since the water chamber 95 is filled with cooling water, the impeller 30 carries cooling water in the vicinity of the center of the water chamber 95 toward the outer periphery of the impeller 30 by centrifugal force due to the rotation of the impeller 30. . Thus, a pumping action due to centrifugal force occurs from the center of the impeller 30 to the outside. Thereby, a pressure difference is generated between the vicinity of the rotation center of the impeller 30 in the water chamber 95 and the outer peripheral side thereof, and the cooling water enters the water chamber 95 from the suction port 95a provided in the vicinity of the rotation center of the impeller 30. Inhaled. And it is pumped to the outer peripheral side by the pump action of the impeller 30, supplied from the discharge port (not shown) provided on the outer peripheral side to each part to be cooled of the engine, and the cooling water circulates.
[0018]
As described above, according to this embodiment, the inner and outer sides of the shaft portion 24 are radially arranged on the side surface of the end portion of the shaft portion 24 on the impeller 30 side (the position where the impeller 30 of the shaft portion 24 is fitted). Since a plurality of through-holes 26 are formed, during the surface treatment by dipping or the like, a plating solution or a coating solution or the like is formed in the hollow shaft portion in which the air at the tip end portion of the shaft portion 24 is discharged and deep-drawn. The surface treatment liquid goes around and the surface treatment is applied to improve the corrosion resistance. Further, the through hole is closed by fitting the shaft and the impeller, and water leakage from the water chamber 95 through the through hole can be prevented.
[0019]
【The invention's effect】
As described above, according to the technical means taken in the invention of claim 1, the pulley and the shaft portion are integrally formed, the shaft portion has a hollow shape, the pulley side end portion opens, and the impeller side Since the end is closed, the number of parts can be reduced and the weight can be reduced. In addition, a plurality of through holes are formed in the side surface of the shaft portion on the side of the impeller side in the radial direction so that the surface treatment liquid can be reliably turned around inside the shaft portion. Since the through hole is closed by fitting the shaft and the impeller, water leakage through the through hole can be prevented.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a water pump according to a first embodiment of the present invention.
FIG. 2 is a longitudinal sectional view of a water pump in the prior art.
[Explanation of symbols]
10 ... Water pump 12 ... Body 12a ... Large diameter part (support part)
12b ... Small diameter part (support part)
DESCRIPTION OF SYMBOLS 14 ... Bearing 20 ... Pulley 24 ... Shaft part 26 ... Through-hole 30 ... Impeller 50 ... Mechanical seal

Claims (1)

Pulley,
A shaft portion that rotates integrally with the pulley;
An impeller that rotates integrally with the shaft portion;
A body having a substantially cylindrical support portion through which the shaft portion is inserted;
A bearing disposed between an outer periphery of the support portion and an inner periphery of the pulley, and rotatably supporting the pulley;
In a water pump comprising a mechanical seal that seals one end side of a cylindrical space defined between an outer peripheral surface of the shaft portion and an inner peripheral surface of the support portion,
The pulley and the shaft portion are integrally formed, the shaft portion has a hollow shape, the pulley side end portion is opened, the impeller side end portion is closed, and the side surface on the impeller side end portion side The water pump is characterized in that a plurality of through holes penetrating the inside and the outside of the shaft portion are formed in the radial direction, and the through holes are closed by fitting the shaft and the impeller.

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