JP3873851B2 - 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 Application Laid-Open No. 2002-89486. This water pump is arranged between a pulley, a shaft that rotates integrally with the pulley, an impeller that rotates integrally with the shaft, a body having the impeller disposed on one end thereof, and a body and the pulley. A water pump provided with a bearing that rotatably supports a pulley and a mechanical seal that seals between the impeller and the bearing.
[0003]
In recent years, a water pump for cooling an automobile engine has been conceived in which a body and a pulley are formed by press working and a single row bearing is used to reduce the cost and weight of parts. On the other hand, in the conventional water pump, since the body is formed by press molding, there is no degree of freedom in the shape of the body, and the shape is limited. For this reason, the water chamber must be formed on the engine side (cylinder block or the like), which may increase the cost of the cylinder block, complicate the mold, or cause casting defects such as nests when manufacturing the cylinder block.
[0004]
[Problems to be solved by the invention]
Therefore, the present invention has a technical problem to provide a water chamber of a water pump with a simple structure at a low cost.
[0005]
[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 that rotates integrally with the pulley, an impeller that rotates integrally with the shaft, A body in which the impeller is disposed on one end side, a bearing disposed between the body and the pulley and rotatably supporting the pulley, and a mechanical sealing between the impeller and the bearing In the water pump including a seal, the body is formed by aluminum casting or resin molding, and a lid portion that forms a water chamber for housing the rotor is formed on the one end side, and an iron is formed on the other end of the body. A cylindrical member made of a system metal is fixed, and the bearing is fixed to the outer periphery of the cylindrical member .
[0006]
According to the above-described means, by forming the body by aluminum casting or resin molding, it is possible to form a lid portion that constitutes a water chamber that accommodates the rotor, and the water chamber of the water pump can be formed at a low cost with a simple structure. Since the bearing is fixed to the outer periphery of a cylindrical member made of an iron-based metal fixed to the other end of the body, the body and the bearing can obtain a substantially equal linear expansion coefficient, The difference in dimensional change between the cylindrical member and the bearing can be reduced at low and high temperatures .
[0009]
In order to solve the above technical problem, the technical means taken in the invention of claim 2 is characterized in that a through hole that communicates a space formed between the mechanical seal and the bearing and the outside is formed in the body. The volume part which opens and opposes the opening part of the exterior side of the said through-hole is provided in the body.
[0010]
According to this means, the body is provided with a volume portion that opens opposite to the opening on the outside of the through hole that communicates the space formed between the mechanical seal and the bearing and the outside. The cooling water leaking from the reservoir can be stored in the volume part.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
A first embodiment of the present invention will be described with reference to FIG.
[0012]
In FIG. 1, the body 12 of the water pump 10 is fixed to the engine cylinder block 90 or the like by a fastening means 13 via a gasket 80 or the like. The body 12 is formed with a lid portion 12a and a stepped cylindrical portion (cylindrical support portion) composed of a large diameter portion 12b and a small diameter portion 12c from the proximal end (one end) side to the distal end (other end) side. Has been. Since the body 12 is formed by aluminum casting or resin molding, the lid 12a can be formed on the base end side. A water chamber 95 that houses the impeller 30 is provided in the lid portion 12a. Further, an inner race of the bearing 14 is fitted and fixed on the small diameter portion 12c of the cylindrical portion. The right end surface of the inner race of the bearing 14 is adjacent to the large diameter portion 12 b of the body 12. There may be a gap between the right end surface of the inner race and the large diameter portion 12b. A mechanical seal 50 is fitted on the inner peripheral side of the large diameter portion 12b.
[0013]
A pulley 20 having a concave shape is fitted on the outer race of the bearing 14 so as to be integrally rotatable. Openings 22a for discharging steam leaked from the mechanical seal 50 to the outside are formed at equiangular intervals at the bottom 22 of the rotating body 18 comprising the pulley 20. Further, a hollow (tubular) shaft 25 extending in a direction away from the bottom portion 22 (right direction in FIG. 1) is integrally formed at the center of the bottom portion 22 of the rotating body 18. The rotating body 18 in which the pulley 20, the bottom portion 22, and the shaft 25 are integrated is formed by pressing a steel plate so that the pulley 20 and the shaft 25 are concentric. Further, the pulley 20, the bottom portion 22, and the shaft 25 may be subjected to corrosion resistance treatment or may not be subjected to corrosion resistance treatment.
[0014]
An impeller 30 is fixed to the right end portion of the shaft 25 so as to be integrally rotatable. 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. The impeller 30 is fixed to the right end portion of the shaft 25 so as to be integrally rotatable by fitting the hollow projection portion 30 c to the right end portion of the hollow shaft 25. The impeller 30 may be subjected to corrosion resistance treatment after press forming a steel plate. The impeller 30 may be molded by a method other than pressing such as resin molding. The impeller 30 is disposed in a water chamber 95 provided in the lid portion 12 a of the body 12. The water chamber 95 is a component of an engine coolant circuit (not shown).
[0015]
A cylindrical space formed between the mechanical seal 50 and the bearing 14, which is a space defined between the outer peripheral surface of the shaft 25 and the inner peripheral surfaces of the large-diameter portion 12 b and the small-diameter portion 12 c of the body 12. A mechanical seal 50 is disposed at one end side (a boundary portion with the water chamber 95) of the space 26, and the mechanical seal 50 prevents the cooling water from leaking outside. Is isolated in a watertight manner. The mechanical seal 50 is fixed to the inner periphery of the large-diameter portion 12b of the cylindrical portion of the body 12, and the shaft 25 is fixed to the shaft 25 so as to be relatively rotatable with respect to the fixed ring 50a and always establish a liquid-tight relationship. And a rotating ring 50b in contact with each other as much as possible.
[0016]
The body 12 is provided with a through hole 27 that communicates between the cylindrical space 26 formed between the mechanical seal 50 and the bearing 14 and the outside, and the sliding between the fixing ring 50a of the mechanical seal 50 and the rotating ring 50b is provided. A minute amount of cooling water is discharged to the outside so as not to hinder the operation of the engine that temporarily leaks due to foreign matters entering the moving surface.
[0017]
Next, the operation of the first embodiment will be described.
[0018]
Through the belt 85 engaged with the belt engaging surface 20a 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 25 integrally formed with the pulley 20 also rotates in the same direction. Then, the impeller 30 integrated with the shaft 25 rotates in a water chamber 95 provided in the lid portion 12 a of the body 12.
[0019]
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.
[0020]
Next, a second embodiment of the present invention will be described based on FIG. Compared with the first embodiment, the second embodiment is composed of a cylindrical member 15 made of an iron-based metal fixed to the tip (other end) side, that is, in the first embodiment. Since only the cylindrical member 15 is replaced at the position of the small diameter portion 12c, the same reference numerals as those in the first embodiment are used for the same configurations as those in the first embodiment, and the description is omitted.
[0021]
The cylindrical member 15 is provided with a flange portion 15a on the large diameter portion 12b side of the body 12, and is fixed to the body 12 via the flange portion 15a by insert molding or caulking at the time of forming the body 12. The collar portion 15a may not be provided, and the cylindrical member 15 may be fixed to the body 12 by insert molding or the like. An inner race of a bearing 14 is fitted on and fixed to the outer periphery of the cylindrical member 15. The right end surface of the inner race of the bearing 14 is adjacent to the collar portion 15a. There may be a gap between the right end surface of the inner race and the collar portion 15a. As a result, the body 12 and the bearing 14 can obtain substantially the same linear expansion coefficient, and the difference in dimensional change between the cylindrical member 15 and the bearing 14 can be reduced at low temperatures and high temperatures. For this reason, in the first embodiment, the bearing life is reduced due to a decrease in the clearance between the inner race and outer race of the bearing 14 and the ball due to the withdrawal of the bearing 14 due to the contraction of the small diameter portion 12c at low temperature and the expansion of the small diameter portion 12c at high temperature. Can be prevented.
[0022]
Next, a third embodiment of the present invention will be described with reference to FIG. Compared with the second embodiment, the third embodiment is provided with a through hole 27 in the body 12 that communicates the cylindrical space (space) 26 formed between the mechanical seal 50 and the bearing 14 and the outside. The only difference is that the body 12 is provided with a volume portion 28 that opens opposite the opening 27a on the outer side of the hole 27. Therefore, the same configurations as those in the second embodiment are the same as those used in the second embodiment. The description will be omitted assuming that the reference numerals are used.
[0023]
The volume portion 28 is composed of a cylindrical wall 12 d and an annular plate 29 toward the through hole 27 side of the lid portion 12 a of the body 12, and opens facing the opening portion 27 a on the outside of the through hole 27. . The plate 29 is fixed to the tip of the cylindrical wall 12d by press-fitting or caulking. Thus, minute cooling water that does not hinder the operation of the engine discharged to the outside can be stored in the volume portion 28. For this reason, the temporary water leak which does not depend on the malfunction of the mechanical seal 50 is not discharged | emitted outside, and the water pump 10 is not replaced | exchanged as a defective product by the trace of water leak.
[0024]
【The invention's effect】
As described above, according to the technical means taken in the invention of claim 1, the lid part forming the water chamber for accommodating the rotor can be formed by forming the body by aluminum casting or resin molding. The water chamber of the water pump can be provided at a low cost with a simple structure, and the bearing is fixed to the outer periphery of a cylindrical member made of a ferrous metal fixed to the other end of the body. The bearing can obtain approximately the same linear expansion coefficient, and the difference in dimensional change between the cylindrical member and the bearing can be reduced at a low temperature and a high temperature .
[0026]
Further, according to the technical means taken in the invention of claim 2 , the space formed between the mechanical seal and the bearing is opened facing the opening on the outside of the through hole that communicates with the outside. By providing the volume part in the body, cooling water leaking from the mechanical seal can be stored in the volume part.
[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 according to a second embodiment of the present invention.
FIG. 3 is a longitudinal sectional view of a water pump according to a third embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Water pump 12 ... Body 12a ... Cover part 14 ... Bearing 15 ... Cylindrical member 20 ... Pulley 25 ... Shaft 26 ... Cylindrical space (space)
27 ... Through-hole 27a ... Opening 28 ... Volume 30 ... Impeller 50 ... Mechanical seal 95 ... Water chamber

Claims (2)

Pulley,
A shaft that rotates integrally with the pulley;
An impeller that rotates integrally with the shaft;
A body having the impeller disposed on one end thereof;
A bearing that is disposed between the body and the pulley and rotatably supports the pulley;
In a water pump comprising a mechanical seal that seals between the impeller and the bearing,
The body is formed by aluminum casting or resin molding, and a lid portion forming a water chamber for housing the rotor is formed on the one end side, and a cylindrical member made of an iron-based metal is fixed to the other end of the body. The water pump is characterized in that the bearing is fixed to the outer periphery of the cylindrical member . A through hole that communicates the space formed between the mechanical seal and the bearing and the outside is provided in the body, and a volume portion that opens opposite the opening on the outside of the through hole is provided in the body. The water pump according to claim 1.

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