JPH0216023Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention provides an engine water pump in which the suction passage is constituted by a pump housing and a bracket interposed between the pump housing and the cylinder block. It concerns pumps.

(Prior art) As a water pump for an engine, an impeller is attached to the tip of a water pump shaft supported by a pump housing to form a water pump assembly, and the impeller is integrated into a water jacket of a cylinder block. There are so-called built-in type water pumps that are attached to the cylinder block so that the impeller protrudes outward from the pump housing. It is necessary to provide a partition wall between the cooling water and the passage to prevent a reduction in the discharge amount or occurrence of cavitation due to the short circuit of cooling water. Conventionally, as a method for forming such a partition wall, as shown in Japanese Utility Model Application Laid-Open No. 57-142126, it has been common to cast the partition wall integrally with the pump housing together with the suction passage.

However, when the partition wall and the suction passage are cast integrally with the pump housing, the structure and shape are complex, making it difficult to use the die-casting method and difficult to manufacture. Moreover, there was a problem that the cost increased.

(Purpose of the invention) In view of the problems of conventional water pumps as described above, the present invention aims to reduce the manufacturing cost by forming the pump housing in parts, thereby making it possible to adopt the die-casting method, and to reduce the manufacturing cost of the water pump. The purpose of this invention is to provide an engine water pump that is both easy to assemble and has improved performance.

(Structure of the invention) The engine water pump of the invention has a bracket having a through hole, which is a through hole for the impeller having a diameter larger than the outer diameter of the impeller, interposed between the pump housing and the cylinder block, and the impeller is inserted into the through hole. The pump housing and the bracket form a suction passage, thereby simplifying the shape of the pump housing and making it possible to die-cast it. It is characterized in that the gap is closed as much as possible by a spacer member held between the pump housing and the bracket, thereby improving ease of assembly and pump performance. .

(Embodiment) The engine water pump of the present invention will be explained below based on the embodiment shown in FIGS. 1 and 2. In FIG. A water pump 2 according to an embodiment of the invention is shown. As shown in FIGS. 1 and 2, this water pump 2 includes a substantially circular bowl-shaped base portion 25 having an annular spacer member mounting groove 32 at the bottom thereof, and an outer portion continuously extending from one side of the base portion 25. The impeller 5 is attached to one end 4a of the boss portion 26 of the pump housing 3, which is formed integrally with a gutter-like portion 24 extending in the direction and a boss portion 26 coaxially continuous with the base portion 25. The cylinder block 1 is configured to rotatably support a water pump shaft 4, and is integrally attached to and detached from the cylinder block 1. A drive pulley 6 is attached to the other end 4b of the water pump shaft 4, and the impeller 5 is rotated by the engine via a drive belt 7 that is passed around the drive pulley 6. In addition, in FIG. 1, the reference numeral 8 is a sealing material.

A pump mounting hole 14 communicating with a water jacket 12 inside the cylinder block 1 is formed in the front end surface 1a of the cylinder block 1. The inner diameter of the pump mounting hole 14 is larger than the outer diameter of the impeller 5 by an appropriate dimension, and the water pump 2 is configured to attach the impeller 5 to the water jacket 1 through the pump mounting hole 14.
A bracket 20, which will be described later, is inserted into the pump housing 3 and between the pump housing 3 and the cylinder block 1.
It is assembled to the cylinder block 1 from the outside of the cylinder block 1 with the two interposed therebetween, and is further tightened and fixed with the mounting bolts 33, 33, . . . .
In addition, in FIG. 1, the reference numeral 11 is a cylinder liner.

As shown in FIGS. 1 and 2, the bracket 20 is a plate-like member having an outer shape that is approximately the same as the outer shape of the abutting surface 3a of the pump housing 3, and is connected to the pump mounting hole 14 of the cylinder block 1.
a first through hole 21 having approximately the same diameter as the first through hole 21;
A second through hole 22 having a smaller diameter is formed at an appropriate distance, and when interposed between the pump housing 3 and the cylinder block 1, the first through hole 21 is overlapped with the pump mounting hole 14. It's becoming like that. Further, the gutter-like portion 24 of the pump housing 3 is covered by a plate portion 27 of the bracket 20, and the first through hole 21 and the pump mounting hole 14 are covered with a plate portion 27 of the bracket 20.
A suction passage 23 communicates with the water jacket 12 via the suction passage 23. Also, a bracket 20 is installed at the most upstream end of the suction passage 23.
A second through hole 22 is opened, and a suction pipe 1 whose one end communicates with a radiator (not shown) is opened in the second through hole 22.
9 is connected.

Further, the pump mounting hole 14 of the cylinder block 1, the first through hole 21 of the bracket 20, and the spacer member mounting groove 32 of the pump housing 3, which overlap and communicate in the axial direction of the water pump shaft 4, have an annular groove extending therebetween. A spacer member 30 is attached. This spacer member 30 has a flange 31 formed on its outer circumferential surface 30a over its entire circumference, and the flange 31 is hooked to the mouth edge 20a of the bracket 20, and its outer end surface 30c is connected to the pump. Insert the mounting bolt 3 while abutting the bottom surface of the spacer member mounting groove 32 of the housing 3.
3, 33... to connect the pump housing 3 and the cylinder block 1, the pump housing 3 and the bracket 20 are automatically clamped, and their movement in the axial and circumferential directions is restricted. . Further, the inner end surface 30b of the spacer member 30 is an inclined surface inclined at approximately the same angle as the inclination angle of the outer surface 5a of the impeller 5,
In the installed state, the inner end surface 30b is as close as possible to the inner surface 5a of the impeller 5, and the gap 35 between the bracket 20 and the first through hole 21 is made as small as possible. Further, the spacer member 30 has a spacer member 30 which is connected to the suction passage 2 in its peripheral wall.
A portion corresponding to 3 is cut out along the shape of the suction passage 23 to ensure a passage area of the suction passage 23.

Next, the action of the water pump 2 will be explained. When the engine is started and the impeller 5 is rotated, the cooling water W is sucked into the water pump 2 side from the suction pipe 19 through the suction passage 23, and is supplied to the impeller 5. It is then pressurized,
Water jacket 12 of cylinder block 1
Forced to the side. At this time, since the gap 35 formed between the spacer member 30 and the impeller 5 is narrowed as much as possible, the high-pressure cooling water on the discharge side flows through the gap 35 to the suction passage 23 side and returns again. The so-called short circuit phenomenon of the coolant sucked into the water pump 2 is prevented as much as possible, and the discharge flow rate of the coolant increases accordingly, resulting in better engine cooling performance. Furthermore, since the short circuit phenomenon hardly occurs, there is no sudden pressure drop of the cooling water, and cavitation can be prevented from occurring.
In this embodiment, even if cavitation occurs and a pit is formed in the spacer member 30, the spacer member 3
Since 0 is a separate member from the pump housing 3, there is an advantage that the pump housing 3 can be reused by simply replacing the spacer member 30, which is inexpensive.

Furthermore, during assembly, the spacer member 30
Since the structure is such that the spacer member 30 is sandwiched between the pump housing 3 and the bracket 20, the spacer member 30 can be prevented from falling off more reliably than when the spacer member 30 is clamped or press-fitted, for example. Unlike when fixing with screws, there is no fear of water leaking to the outside, and there are also advantages such as ease of tolerance management compared to press-fitting.

(Effect of the invention) In the engine water pump of the invention, a bracket is interposed between the pump housing and the cylinder block to which the pump housing is attached, and the impeller is disposed within the water jacket through a through hole formed in the bracket. At the same time, the bracket and the pump housing form a suction passage, and the spacer member interposed between the bracket and the pump housing partitions the suction passage and the impeller. The structure of the pump housing is improved compared to a case where the suction passage and the partition wall that partitions between the suction passage and the impeller are integrally cast with the pump housing as in the case of a pump (for example, Japanese Utility Model Publication No. 57-142126). Moreover, the pump housing is simple in shape, and thus the pump housing can be die-cast, thereby promoting reduction in manufacturing costs.

Furthermore, since the gap between the through hole provided in the bracket and the impeller is closed by a spacer member, the short circuit phenomenon of cooling water is prevented as much as possible, and as a result, the flow rate of cooling water is reduced. This has the effect of increasing the cooling efficiency (improving cooling efficiency) and preventing the occurrence of capitation (improving durability).

In addition, since the spacer member is sandwiched between the pump housing and the bracket, each part is easier to assemble than when the spacer member is fixed with screws or press-fitted, which reduces costs. It also has the effect of making it possible to achieve

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a water pump according to an embodiment of the present invention, and FIG. 2 is an exploded perspective view of essential parts of the water pump shown in FIG. 1... Cylinder block, 2... Water pump, 3... Pump housing, 4... Water pump shaft, 5... Impeller, 11... Cylinder liner, 19... Suction pipe, 2
0...Bracket, 21, 22...Through hole, 23
... Suction passage, 30 ... Spacer member, 3
1...Flame, 33...Mounting bolt, 35...Gap.

Claims (1)

[Scope of utility model registration request] In a water pump where the pump housing that supports the water pump is attached to the cylinder block, and the impeller fixed to the tip of the water pump shaft is disposed inside the water jacket of the cylinder block, there is a space between the pump housing and the cylinder block that is smaller than the outer diameter of the impeller. A bracket having a large diameter through hole is interposed, the impeller is disposed through the through hole in the water jacket, a suction passage is formed between the pump housing and the bracket, and a suction passage is formed between the impeller and the bracket. A water pump for an engine, characterized in that a gap between the water pump and the hole is closed by a spacer member, and the spacer member is held between a pump housing and a bracket.