JPH0333920B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a body structure of a water pump installed as an auxiliary device in a small water-cooled engine or the like.

(Prior Art) Conventionally, as shown in FIGS. 2 and 3, a water pump body 4 having an impeller housing portion 1, a water outlet 2, and a water passage 3 extending from the impeller housing portion 1 to the water outlet 2 has a different shape. Due to the complexity, methods such as (1) providing a core (Figure 2), (2) forming the water passage 3 in combination with other parts such as a water pump cover (Figure 3), etc. However, both of these methods lead to an increase in costs, and in particular, in the conventional structure shown in FIG. 3, the area of the mating surface between the water pump body 4 and the water pump cover 5 becomes large, and the sealing performance tends to deteriorate. In addition, a right-angled corner 6 is formed at the bend of the water passage toward the spout 2 side, making it impossible to form a smooth flow path. As a prior art, there is Japanese Patent Application Laid-Open No. 56-60817.

(Objectives of the Invention) The present invention is to enable die casting production using only a two-sided mold, to improve sealing performance by reducing the area of the mating surface with the water pump cover, and to improve the sealing performance of the water passage near the water outlet. The purpose is to make curved portions into smooth curves, etc.

(Structure of the Invention) The present invention includes an impeller housing part that surrounds an impeller supported by a pump body and opens toward the front, a water outlet that extends laterally from the impeller housing part and opens toward the rear, and a water outlet that extends from the impeller housing part to the water outlet. In a die-cast water pump body that has a water passage and the impeller housing and the front opening of the water passage are closed with a cover with a water inlet, the mating surfaces of the front and rear die-cast molds are A water pump characterized in that the cross section of the passage is inclined so as to move away from the impeller toward the front, and a front wall with a smoothly curved inner surface is formed on the back side of the water spout up to the mating surface of the mold. body. The back side of the water spout has a smooth curve so that the inner surface recedes as it goes toward the water spout, so the water flowing out from the impeller housing passes through the smoothly curved water passage toward the water spout, and flows into the engine body, for example. The cooling water is supplied to the internal cooling water passage.

(Example) In FIG. 1 showing an example, the same reference numerals as those in FIGS. 2 and 3 indicate corresponding parts. The water pump body 4 has an impeller housing part 1 that is open toward the front of the open type impeller 10 (the open side, that is, the mold A side), and an impeller housing part 1 that is open toward the front (opening side, that is, the mold A side), and an impeller housing part 1 that is open to the right side of the impeller housing part 1 and is facing rearward in the opposite direction to the opening direction of the impeller 10. It is the same as the conventional model in that it includes an open water spout 2 and a water passage 3 leading from the impeller housing part 1 to the water spout 2, but an inner surface 11 is provided on the back side (front side) of the water spout 2 toward the water spout 2 side. Since the front wall 12 is integrally provided with a smoothly curved front wall 12 that recedes as it goes, the half of the water passage 3 on the impeller housing 1 side opens forward, and the half on the spout 2 side is the spout 2 part. It becomes an open shape facing backwards. Also, because of the presence of the front wall 12, the amount of protrusion of the water pump cover 5 toward the spout 2 side is reduced, and the rear surface of the outer circumference of the smaller cover 5 is connected to the water pump body 4 via the annular seal 13. It will be fastened to the seat 14 with a plurality of bolts (not shown). The cover 5 has a water inlet 15 concentric with the impeller 10. The impeller 10 is fixed to the front end of a pump shaft 16, which is rotatably fitted into a bearing hole 17 of the water pump body 4, and has a drive gear 18 at its rear end. 1
9 is an oil seal, and 20 is a mechanical seal. The water pump body 4 is attached to a seat (not shown) of the engine body at the stepped portion 21 with a plurality of bolts. Further, the water spout 2 is connected to a water passage 23 within the engine body 22.

In such a water pump body 4, the mating surfaces 25 of the molds A and B are arranged so that the mating surfaces 25 of the molds A and B move away from the impeller as they move forward on a cross section that crosses the water passage 3 from the end 2a of the water outlet 2 near the impeller housing part 1. Because it is formed at an angle, it can be obtained using only two molds. That is, the mold A includes the inner surface 26 of the impeller housing part 1, the inner surface 27 of the water passage from the impeller housing part 1 to the water outlet 2 up to the mating surface 25, the seat 14, the outer surface 28 of the front wall 12, and the mating surface 25. is included as part of the inner surface of the mold. In addition, the mold B includes the outer surface 29 of the impeller housing part 1, the outer surface 30 of the water passage 3 from the impeller housing part 1 to the mating surface 25, the inner surface 11 of the front wall on the back side of the water spout 2, and the mating surface 25 as part of the inner surface of the mold. It is prepared as a department.

When manufacturing the water pump body 4 by die casting, two molds A and B are pressed together at the mating surface 25, and molten metal such as aluminum alloy is press-fitted into the space between the two molds. Then, by separating the molds A and B from each other in the direction of the arrow after die casting, a water pump body having the cross-sectional shape shown in FIG. 1 is completed.

(Effects of the invention) (1) Since die casting can be produced using only two molds A and B, costs can be reduced.

(2) Since the front wall 12 is formed on the back side of the water spout 2 up to the mating surface of the mold, the area of the mating surface with the water pump cover 5 can be reduced.
The sealing performance is improved accordingly.

(3) Since the inner surface 11 of the front wall 12 is smoothly curved, flow path loss is reduced and performance is improved. Also, compared to the conventional example shown in FIG.
1 is impinged on by substantially laminar water, which also reduces flow path loss.

(4) Furthermore, in the present invention, since the mating surfaces 25 of the molds A and B are inclined so as to move away from the impeller 10 toward the front, the adhesion when the molds A and B are brought together is increased. This prevents the occurrence of burrs from the ends 31, 2a into the water passage 3, and also makes it easier to separate the molds A and B in the direction of the arrow. Also, at the same time impeller 10
Since the swirl chamber surrounding the water pump and the smooth water passage 3 leading to the spout 2 can be integrally formed, there is an advantage that a high-performance water pump body can be manufactured at low cost.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of a water pump employing the present invention, and FIGS. 2 and 3 are vertical cross-sectional views showing a conventional structure. DESCRIPTION OF SYMBOLS 1... Impeller housing part, 2... Water outlet, 3... Water passage, 5... Water pump cover, 10... Impeller, 11... Inner surface, 25...
...Mold mating surface.

Claims (1)

[Claims] 1 The impeller housing has an impeller housing part that surrounds the impeller supported by the pump body and opens toward the front, a water spout that extends laterally from the impeller housing part and opens toward the rear, and a water passage from the impeller housing part to the water spout. In a die-cast water pump body in which the front opening of the water outlet and the water passage are closed by a cover with a water intake port, the mating surfaces of the front and rear die-cast molds are moved forward to the cross section of the water passage at the end of the water outlet near the impeller housing part. A body of a water pump, characterized in that the front wall is inclined so as to move away from the impeller, and a front wall with a smoothly curved inner surface is formed on the back side of the water spout up to the mating surface of the mold.