JP2004052723A - Water pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the moldability of a shaft while securing the strength of a pulley, and to reduce cost. <P>SOLUTION: This water pump 10 is provided with the pulley 18; the shaft 25 rotated integrally with the pulley 18; an impeller 30 rotated integrally with the shaft 25; a body 12 forming a water chamber 95 where the impeller 30 is disposed; a bearing 14 disposed between the body 12 and the pulley 18 to support the pulley 18 rotatably; and a mechanical seal 50 for carrying out sealing between the water chamber 95 and the bearing 14. In this case, the plate thickness of the pulley 18 is made thicker than that of the shaft 25. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a water pump, and more particularly to a water pump for an automobile.
[0002]
[Prior art]
A conventional water pump is disclosed in, for example, Japanese Patent Application Laid-Open No. 2002-158993. The water pump includes a pulley, a shaft that rotates integrally with the pulley, an impeller that rotates integrally with the shaft, a body that forms a water chamber in which the impeller is disposed, and a body that rotatably supports the pulley. And a mechanical seal for sealing the bearing against the water chamber. Further, in recent years, a water pump using a single-row bearing in which a body and a pulley are formed by press working and a single row bearing has been considered due to a need for cost reduction and weight reduction of parts. In the case of this water pump, the pulley and the shaft are integrally formed by press forming, and the shaft is formed by deep drawing.
[0003]
On the other hand, in order to facilitate deep drawing, reduce the number of steps, and reduce the processing cost and the die cost, it is necessary to set the thickness of the shaft to be thin.
[0004]
[Problems to be solved by the invention]
However, if the plate thickness is reduced to improve the formability of the shaft, the stress generated in the pulley becomes larger than the allowable stress of the metal due to the belt load, the pulley is deformed, the water pump does not operate, and an overheating problem occurs. There is fear. On the other hand, if the plate thickness is increased, the moldability of the shaft deteriorates, which may lead to an increase in cost.
[0005]
Therefore, an object of the present invention is to ensure the strength of the pulley, improve the moldability of the shaft, and reduce the cost.
[0006]
[Means for Solving the Problems]
The technical means taken by the invention of claim 1 to solve the above technical problem includes a pulley, a shaft that rotates integrally with the pulley, an impeller that rotates integrally with the shaft, A body forming a water chamber in which the impeller is provided, a bearing provided between the body and the pulley, and a bearing for rotatably supporting the pulley; and sealing between the water chamber and the bearing. In the water pump having the mechanical seal described above, the thickness of the pulley is greater than the thickness of the shaft.
[0007]
According to this means, by making the plate thickness of the pulley larger than the plate thickness of the shaft, it is possible to prevent the deformation of the pulley due to the belt load and improve the formability of the shaft.
[0008]
According to a second aspect of the present invention, there is provided a motor control apparatus comprising the pulley and the shaft formed of separate members. An arm portion fixed to the outer peripheral surface is provided, and the pulley is fixed to the outer peripheral surface of the arm portion.
[0009]
According to this means, by forming the pulley and the shaft as separate members, it is possible to easily perform deep drawing of the shaft. Thereby, the number of molding steps can be reduced, and the processing cost and the die cost can be reduced.
[0010]
According to a third aspect of the present invention, in order to solve the above technical problem, in addition to the first aspect, the pulley includes a first cylindrical portion provided on an outer peripheral side and an inner peripheral portion. And a connecting portion connecting the inside of the second cylindrical portion fixed to the arm portion and having a bottomed cylindrical shape.
[0011]
According to this means, a thick pulley can be formed by press molding, so that the number of molding steps can be reduced and the processing cost and the die cost can be reduced.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described with reference to FIG.
[0013]
In FIG. 1, a body 12 of the water pump 10 is fixed to an engine cylinder block 90 by a fastening means 13 via a gasket 80 or the like. The body 12 has a stepped cylindrical portion having a large diameter portion 12a and a small diameter portion 12b. The inner race of the bearing 14 is press-fitted and fixed to the outer peripheral surface of the small diameter portion 12b of the cylindrical portion. The right end face of the inner race of the bearing 14 is adjacent to the large diameter portion 12 a of the body 12. Note that a gap may be provided between the right end surface of the inner race and the large diameter portion 12a.
[0014]
The outer peripheral portion 17 a of the arm portion 17 of the shaft 25 is press-fitted into the outer peripheral surface of the outer race of the bearing 14. A pulley 18 is press-fitted and fixed outside the outer peripheral portion 17a. The pulley 18 has a bottomed cylindrical shape, and an inner peripheral portion (first cylindrical portion) 18a is press-fitted into an outer peripheral portion of an outer peripheral portion 17a of the arm portion 17, and a water pump 10 is mounted on the bottom portion (connection portion) 18b by an engine cylinder. An opening 18c used for fixing to the block 90 is formed. A belt 85 is wound around the outer peripheral portion (first cylindrical portion) 18d. Note that the pulley 18 may be formed by resin molding or the like in addition to press molding.
[0015]
The arm portion 17 of the shaft 25 has a bottomed cylindrical shape, the outer peripheral portion 17a is press-fitted into the outer peripheral surface of the outer race of the bearing 14, and the bottom portion 17b has an opening 17c for discharging water droplets leaking from the mechanical seal 50 to the outside. They are formed at equal angular intervals. At the center of the bottom portion 17b of the arm portion 17, a cylindrical hollow shaft portion 24 extending in a direction away from the bottom portion 17b (rightward in FIG. 1) and having an open end at the bottom portion 17b is integrally formed and joined. Have been. A bottom wall is formed at the end of the shaft 24 and is closed.
[0016]
As described above, by forming the driven portion 16 from separate members of the pulley 18 and the shaft 25, it is possible to easily perform the deep drawing of the shaft 25, and to make the plate thickness of the pulley 18 larger than the plate thickness of the shaft 25. The deformation of the pulley 18 due to the belt load can be prevented. In addition, the number of molding steps can be reduced, and processing costs and mold costs can be reduced. In addition, the thick pulley 18 can be formed by press molding, so that the number of molding steps can be reduced and the processing cost and the die cost can be reduced. The pulley 18 and the shaft 25 are subjected to a corrosion-resistant treatment by plating or painting. Further, the anticorrosion treatment may not be performed.
[0017]
An impeller 30 is fitted to the right end of the shaft portion 24 so as to be integrally rotatable. The impeller 30 is formed integrally with a base 30a, a plurality of blades 30b protruding from a peripheral edge of the right side of the base 30a, and a cylindrical hollow protrusion 30c into which the shaft 24 is fitted at the center of the base 30a. A cap 30d for securing the fitting strength between the impeller 30 and the shaft portion 24 is pressed into the outer periphery of the portion 30c. The cap 30d may be omitted as long as the fitting strength can be secured. The impeller 30 may be subjected to a corrosion-resistant treatment after press-forming a steel plate. The impeller 30 may be processed by resin molding or other molding methods. The impeller 30 is provided in a water chamber 95 formed inside the engine cylinder block 90 and the like and having an opening closed by the body 12. The water chamber 95 is a component of an engine cooling water circuit (not shown).
[0018]
One end of a 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 (a boundary portion with the water chamber 95) is provided with a mechanical member. A seal 50 is provided to watertightly separate the outside and the water chamber 95 so that the cooling water does not leak outside. The mechanical seal 50 is fixed to the fixed ring 50a fixed to the inner peripheral side of the large-diameter portion 12a of the cylindrical portion of the body 12, and is fixed to the shaft portion 24. And a rotating ring 50b that comes into contact as much as possible.
[0019]
Next, the operation of the present embodiment will be described.
[0020]
The pulley 18 is rotated by the torque transmitted from the output shaft of the engine (not shown) via the belt 85 engaged with the belt engaging surface 18e of the pulley 18. With the rotation of the pulley 18, the shaft 24 integrally formed with the arm 17 fixed to the inner periphery of the inner periphery 18a of the pulley 18 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.
[0021]
At this time, a belt load is applied to the pulley 18 by the belt 85, but since the plate thickness of the pulley 18 can be made larger than the plate thickness of the shaft 25, deformation of the pulley 18 due to the belt load can be prevented.
[0022]
Now, since the water chamber 95 is filled with the cooling water, the impeller 30 conveys the cooling water near the center of the water chamber 95 toward the outer periphery of the impeller 30 by the centrifugal force generated by the rotation of the impeller 30. . In this way, a centrifugal pump action occurs from the center of the impeller 30 to the outside. As a result, a pressure difference is generated between the vicinity of the rotation center of the impeller 30 and the outer peripheral side in the water chamber 95, and the cooling water flows from the suction port 95a provided near the rotation center of the impeller 30 into the water chamber 95. Inhaled. Then, the water is pressure-fed to the outer peripheral side by the pump action of the impeller 30 and supplied to each part to be cooled of the engine from a discharge port (not shown) provided on the outer peripheral side, and the cooling water circulates.
[0023]
【The invention's effect】
As described above, according to the technical measures taken in the first aspect of the present invention, the thickness of the pulley is made larger than the thickness of the shaft, so that the pulley can be prevented from being deformed due to the belt load and the shaft can be prevented from being deformed. Can be improved.
[0024]
Further, according to the technical means adopted in the second aspect of the invention, the pulley and the shaft are formed as separate members, so that the deep drawing of the shaft can be easily performed. Thereby, the number of molding steps can be reduced, and the processing cost and the die cost can be reduced.
[0025]
Further, according to the technical measures taken in the third aspect of the present invention, a thick pulley can be formed by press molding, and the number of molding steps can be reduced, and the processing cost and the die cost can be reduced.
[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.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Water pump 12 ... Body 14 ... Bearing 17 ... Arm part 18 ... Pulley 18a ... Inner peripheral part (1st cylindrical part)
18b: bottom part (connection part)
18d ... outer peripheral part (second cylindrical part)
25 shaft 30 impeller 50 mechanical seal 95 water chamber

Claims (3)

A pulley,
A shaft that rotates integrally with the pulley;
An impeller that rotates integrally with the shaft,
A body forming a water chamber in which the impeller is disposed;
A bearing disposed between the body and the pulley and rotatably supporting the pulley;
In a water pump including a mechanical seal that seals between the water chamber and the bearing,
A water pump, wherein the thickness of the pulley is greater than the thickness of the shaft. The pulley and the shaft are formed of different members, the shaft includes an arm portion fixed to an outer peripheral surface of the bearing, and the pulley is fixed to an outer peripheral surface of the arm portion. The described water pump. The pulley has a bottomed cylindrical shape including a connecting portion that connects a first cylindrical portion provided on an outer peripheral side and a second cylindrical portion provided on an inner peripheral side and fixed to the arm portion. The water pump according to claim 2, wherein

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