JPH0545840Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a mounting structure for a pump body of a water pump that is attached to, for example, an internal combustion engine.

BACKGROUND OF THE INVENTION As is well known, internal combustion engines for automobiles are equipped with water pumps that forcefully circulate cooling water through cylinder blocks and cylinder heads. The pump body of this water pump is integrally molded from sheet metal or aluminum die-casting, and consists of a substantially circular body body and a mounting flange on the outer periphery of the body body. Bolt holes are drilled therein, and a flat mounting surface is formed on the front surface, which faces the seat surface of the front end of the cylinder block, which is the object to be mounted, with a gasket interposed therebetween. To attach this pump body to the cylinder block,
Align the mounting surface of the pump body with the seat surface of the cylinder block via a gasket, screw the bolts inserted into the plurality of bolt holes mentioned above into the bolt thread holes on the cylinder block side, and tighten to the specified rotational torque. (See US Pat. No. 3,620,042, etc.).

Problems to be Solved by the Invention However, in the conventional pump body mounting structure described above, the entire mounting surface of the pump body was formed flat, and emphasis was placed only on the flatness and smoothness of the mounting surface. When the bolt is tightened,
In contrast to the high contact pressure on the mounting surface near the bolt hole, the contact pressure on the mounting surface other than the vicinity of the bolt hole, that is, between adjacent bolt holes, is significantly lower, resulting in an overall uneven contact pressure. Therefore, an unbalanced load is generated on the gasket, which deteriorates the sealing performance, and when the internal pressure of the pump chamber increases when the pump is driven, there is a possibility that cooling water may leak from the vicinity of the mounting surface between the bolt holes.

Therefore, in the past, in order to disperse and equalize the surface pressure on the mounting surface, the overall thickness of the gasket had to be made thicker than necessary.

Means for Solving the Problems The present invention was devised in view of the above-mentioned conventional problems, and is particularly characterized in that the mounting surface between adjacent bolt holes of the mounting flange is formed in a convex shape toward the object to be mounted. It is said that

Effects According to the present invention having the above configuration, when the pump body is attached to the object to be attached, as the bolts are tightened, the convex mounting surface first comes into pressure contact with the seat surface of the object to be attached, and then the mounting surface near the bolt hole is tightened. The surfaces are pressed together. Therefore, when the bolt is further tightened, the surface pressure against the seat surface will be slightly higher on the convex mounting surface than on the mounting surface near the bolt hole, but ultimately the bolt hole will receive the bolt tightening torque directly. Since the surface pressure on nearby mounting surfaces also increases, the surface pressure becomes uniform over the entire mounting surface.

Embodiment Hereinafter, an embodiment of the present invention will be described in detail based on the drawings.

FIG. 3 shows a water pump for an automobile internal combustion engine to which this embodiment is applied, and this water pump includes a substantially circular pump body 1, a bearing 2 fixed to the rear end side of the pump body 1,
A rotating shaft 4 that is supported inside the bearing 2 and to which rotational force is transmitted by the crankshaft of the engine via a pulley (not shown) and a pulley seat 3, and a vane fixed to one end of the rotating shaft 4. 5.

As shown in FIGS. 1 and 2, the pump body 1 includes a body body 6 in the center of which the bearing 2 is fixed, and a mounting flange 7 integrally provided on the outer periphery of the body body 6 made of sheet metal or aluminum. It is molded in one piece by die-casting. The mounting flange 7 has four bolt holes 9 in the circumferential direction through which bolts 8 are inserted, and has a flat seating surface on the front end of the cylinder block 21 of the internal combustion engine, which is the object to be mounted. 21a is formed with a mounting surface 11 that comes into contact with a liquid gasket 10, which will be described later. A substantially annular groove 12 filled with the liquid packing 10 is formed in the circumferential center of the mounting surface 11 .

In addition, the pump body 1 has a cylindrical portion 13 bent inward along the axial direction of the rotating shaft 4 at the center of the rear end that bulges outward. A hole 14 is formed.

On the other hand, the bearing 2 has two bearing grooves 4a on the outer peripheral surface of the rotating shaft 4, as shown in FIG.
A plurality of bearing balls 2a guided by 4a,
2a, and a cylindrical outer wall 2b that holds the bearing balls 2a, 2a.
A hardened, highly rigid cylindrical extension portion 15 is continuously formed on the fixed end side of b, protruding in the axial direction. The extension part 15 has an outer diameter set to be the same as or slightly larger than the inner diameter of the fixing hole 14, and is inserted into the fixing hole 14 with an intermediate fit or an interference fit. Furthermore, the inner peripheral surface of the extension portion 15 and the fixing hole 14, that is, the cylindrical portion 1
The inner circumferential surface of No. 3 is joined by laser welding, which is less affected by heat. Further, a mechanical seal 16 is provided between the extension portion 15 and the vane 5 to prevent cooling water from leaking into the bearing 2.

As shown in FIGS. 1 and 2, in the mounting flange 7, the first mounting surface 11a between the adjacent bolt holes 9 in the mounting surface 11 has the bolt holes 9...
It is formed into a substantially arcuate convex shape that smoothly protrudes forward (toward the attached body 21 side) at a height L of approximately 0.2 to 0.3 mm from the nearby second mounting surface 11b. Therefore,
The second mounting surface 11b, on the contrary, has a concave shape.

Therefore, according to this embodiment, after each component is assembled to the pump body 1, when the pump body 1 is attached to the cylinder block 21, the bolts 8... are screwed into the bolt thread holes of the cylinder block 21. When tightening, first the first mounting surface 11a comes into pressure contact with the seat surface 21a via the liquid packing 10, and then the second mounting surface 11b comes into pressure contact with the seat surface 21a. Therefore, when the bolts 8... are further tightened, the surface pressure of the mounting surface 11 against the seat surface 21a will be slightly higher on the first mounting surface 11a than on the second mounting surface 11b, but in the end, The surface pressure of the second mounting surface 11b, which directly receives the maximum tightening torque of the bolts 8, also increases. Therefore, the entire mounting surface 11 has a uniform surface pressure. Therefore, good sealing performance by the liquid packing 10 is maintained.

In addition, in this embodiment, the extension part 15 is not simply press-fitted into the fixing hole 14, but is inserted through the fixing hole 14 with an intermediate fit or interference fit, and then joined by welding. Extension part 1
5 is inserted into the thin fixing hole 14, the diameter of the pump body 1 side expands, but since the bearing 2 is inserted at a position away from the bearing ball 2a, no tightening force is applied to the bearing ball 2a side. Therefore, occurrence of uneven load on the bearing ball 2a is reliably prevented, and optimum clearance is always ensured.

It should be noted that the present invention is not limited to the water pump of the above embodiment, but can of course be applied to oil pumps, air pumps, etc.

Effects of the invention As is clear from the above explanation, according to the invention, the mounting surface between adjacent bolt holes of the mounting flange is formed in a convex shape toward the object to be mounted, so that the entire mounting surface after bolt tightening is The pressure becomes uniform, and uneven loads on the seal member between the mounting surface and the object to be mounted are prevented. As a result,
Good sealing performance by the sealing member is maintained,
Water leakage, etc. is reliably prevented.

[Brief explanation of the drawing]

Fig. 1 is a view taken in the direction of arrow A in Fig. 3 showing an embodiment of the present invention, Fig. 2 is a view taken in the direction of arrow B in Fig. 1, and Fig. 3 is a partial sectional view showing the overall structure of this embodiment. be. 1...Pump body, 6...Body body, 7...
...Mounting flange, 8...Bolt, 9...Bolt hole, 10...Liquid packing (sealing member), 11
... Mounting surface, 11a... First mounting surface (mounting surface between bolt holes).

Claims (1)

[Scope of utility model registration request] In a pump body mounting structure in which a bolt hole is formed in a mounting flange provided on the outer periphery of the body main body, and the pump body is mounted to an object to be mounted via a sealing member by tightening a bolt inserted into the bolt hole, the bolt adjacent to the mounting flange A pump body mounting structure characterized in that the mounting surface between the holes is formed in a convex shape toward the object to be mounted.