JPS59119079A - Cooling water pump - Google Patents

Abstract

PURPOSE:To prevent rupture of cap members due to thermal stress, by making the cap members with a ceramics material, and arranging small metal wires on the inside of the cap members in a unitary manner. CONSTITUTION:An inner cap member 7 and an outer cap member 8 are both made of a ceramics material, and they incorporates therein small metal wires 15 arranged in the form of a net. When a pump is set into operation, the radially inner section of the cap members 7, 8 are held in sliding contact with a vane portion 12b, so that frictional heat is produced from the section. On the other hand, the radially outer section of the cap members 7, 8 is cooled by cooling water, so that the temperature at the section is kept low. Resultantly, a temperature gradient is caused at the boundary area. However, since heat is transmitted via the small metal wires 15 arranged on the inside of the cap members 7, 8, the temperature gradient is made gentle, so that it is enabled to prevent rupture of the cap members due to thermal stress.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cooling water pump suitable for outboard motors and other marine engines, and more specifically, the parts forming the inner surface of the pump chamber are made of ceramic.

The pump chamber is composed of a cylindrical casing and a lid member that closes both ends of the casing, and houses a rubber-like impeller that is attached to the drive shaft via a boss.When the impeller rotates, water is pumped out from the suction port as cooling water. It sucks in water from the sea or river and supplies it to the engine through the outlet.

Therefore, ceramicizing the inner surface of the pump chamber increases the wear resistance of the casing, which is particularly advantageous when the cooling water contains sand or soil.

However, the inner periphery of the lid member, which constitutes the inner wall of the cooling water pump, is rubbed against the side surface of the shaft of the impeller during operation of the pump and becomes hot, and the outer periphery is heated by the cooling water introduced into the impeller's shaft. Because it is kept at a low temperature, a severe temperature gradient occurs near the boundary, making it easy for cracks to occur.

This invention aims to prevent the occurrence of the above-mentioned cracks, and is characterized in that a thin metal wire is included in the ceramic disc constituting the lid member.

The present invention will be explained below with reference to illustrated embodiments. In the figure, 1 is a case of an outboard motor, in which a pump drive shaft 2 is rotatably supported. 3 is a cooling water suction port, and 4 is a discharge port.

A cooling water pump 5 is provided at the end of the case 1.

The cooling water pump 5 includes a cylindrical ceramic casing 6 in a case 1, and an inner lid member 7 and an outer lid member 8 made of ceramics with the casing 6 in between. It is closed to form a pump chamber 11. A rubber impeller 12 is housed in the pump chamber 11, and includes a shaft portion 12a and a vane portion 12b.

12c is a boss baked on the inner surface of the shaft portion 12a;
It has an oval-shaped shaft hole.

The end of the pump drive shaft 2 protrudes into the pump chamber 11 through the inner lid member 7, and its two-chamfered portion engages with the oval shaft hole so as to be movable only in the axial direction.

In this way, the impeller 12 has its side surfaces compressed by the inner lid member 7 and the outer lid member 8, and its outer surface compressed by the casing 6.
The vane portions 12b are mutually configured to be watertight.

Here, the inner lid member 7 and the outer lid member 8 are made of ceramic fired into a disk shape, as shown in FIG.
Inside is a thin metal wire 15 woven like a wire mesh. In addition, this metal may generally be iron, but is not limited to this.
Any material may be used as long as it can withstand the high heat during ceramic firing. Further, it is not necessary to wrap the ceramic plates before firing (it is also optional to sandwich the thin metal wire 15 between the two fired ceramic plates and bond them with an adhesive).

As described above, the cooling water pump of the present invention houses an impeller in a cylindrical casing having a suction port and a discharge port, and closes both ends of the impeller with a lid member to form a pump chamber, and the lid member is made of ceramic. The inner cover member 7 and the outer cover member 8 are formed with a thin metal wire integrally wrapped and contained inside the cover member, and when the pump is operated, the inner circumferential sides of the inner cover member 7 and the outer cover member 8 are Although heat is generated by rubbing against the vane portion 12b, the outer circumferential side is kept at a low temperature by the cooling water, resulting in a temperature gradient at the boundary, but heat is transferred by the thin metal wires contained inside, and the above-mentioned Since the temperature gradient becomes gentle, destruction due to thermal stress is prevented. Moreover, the elasticity of the metal wire can also prevent breakage, resulting in an effect of further increasing durability.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a cross-sectional view of a cooling water pump, FIG. 2 is a cross-sectional view along the line ■-■, and FIG. 3 is a partially cutaway perspective view of the main parts. It is. 5-11 Cooling water pump, 6----Casing, 7
-----Inner lid member, 8-111 Outer lid member, 15
---Thin metal wire, Patent applicant Yamaha Motor Co., Ltd. Procedural amendment (voluntary) Commissioner of the Patent Office Kazuo Wakasugi 1, Indication of the case Patent Application No. 229535 of 1982 2, Title of the invention Cooling water Pump 3, Relationship with the case of the person making the amendment Patent applicant address 2500 Shingai, Iwata City, Shizuoka Prefecture 438 Map 5, Contents of the amendment

Claims (1)

[Claims] The impeller is housed in a cylindrical casing having a suction port and a discharge port, and both ends of the impeller are closed with a lid member to form a pump chamber. A cooling pump that integrally incorporates thin wires.