JPH1150995A - Mechanical seal for water pump and method for forming it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the surface roughening of a mechanical seal for a water pump. SOLUTION: In a mechanical seal for a water pump, provided with a ceramic ring 6 on the rotating side and a carbon ring 1 on the non-rotating side, and for preventing water leakage by the sliding surfaces 12 of the ceramic ring 6 and the carbon ring 1, liquid films 13 are formed on the whole sliding surfaces 12 before the first operation of the water pump. In a method for forming the mechanical seal for the water pump, the liquid films 13 are formed on the whole mechanical seal sliding surfaces 12, and the first operation of the water pump is started.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mechanical seal for a water pump used for cooling water circulation of an internal combustion engine cooling system, and a method of forming (forming) the same.

[0002]

2. Description of the Related Art Water pumps for internal combustion engines
This is known from Japanese Patent Application Laid-Open Nos. 8-129097 and 61-108895. In the water pump,
The pump shaft is rotatably supported by the bearing, and the impeller is mounted on the pump shaft. The rotation of the engine crankshaft is transmitted to the pump shaft via the pulley, and rotates the pump shaft to rotate the impeller and circulate engine cooling water. The space where the bearing that supports the pump shaft is located,
The mechanical seal seals off the space through which the engine cooling water flows. The mechanical seal usually has a rotating ceramic ring that rotates with the impeller,
It is composed of a rotating contact sliding surface with the non-rotating carbon ring pressed against it by a spring or the like. Since the carbon ring is pressed against the ceramic ring, during engine tests, etc., the engine cooling water has not entered the rotating sliding contact surface, and the rotating sliding contact surface is in a dry state. During operation, the high temperature caused by the sliding causes the carbon of the carbon ring to adhere to the sliding surface of the ceramic ring, causing unevenness on the sliding surface of the ceramic ring and the sliding surface of the carbon ring. When the ceramic ring rotates, the carbon ring and the ceramic ring dance and the sliding surface opens, causing unequal liquid components in the engine cooling water and foreign substances contained in the cooling water to enter. As a result, they accumulate on the sliding surface and cause surface roughness to progress, eventually causing water leakage. When the leaked water reaches the bearing, the rotation of the pump is hindered, and the rotation of the engine is hindered. In order to alleviate this problem, in Japanese Utility Model Application Laid-Open Nos. 58-129097 and 61-108895, a hole is formed in the ceramic ring to extend to the sliding surface, and engine cooling water is passed through the hole. And lubricate it.

[0003]

However, the above conventional structure has the following problems. When the ceramic ring rotates, only the annular part with the width of the hole diameter can be lubricated,
That portion is only a part of the entire width of the ceramic ring sliding surface, and the remaining sliding surface remains in a dry state, so that carbon adhesion and antifreeze component accumulation occur there. Also, before the ceramic ring rotates, the annular portion (the portion lubricated with water from the holes) is also in a dry state, and until the ceramic ring starts rotating and the annular portion is completely lubricated, the annular portion is in a dry state. Even if the coagulation of carbon and the accumulation amount of antifreeze component per time are small, the number of repeated start and stop of the pump increases, and the above-mentioned annular portion cannot be neglected. Adhesion and accumulation of antifreeze components occur. SUMMARY OF THE INVENTION An object of the present invention is to provide a mechanical seal for a water pump and a method for forming the same (a method for forming a mechanical seal for preventing the surface roughness of a sliding surface of a mechanical seal and the adhesion of carbon due to operation of the sliding surface in a dry state, thereby preventing water leakage). ).

[0004]

The present invention to achieve the above object is as follows. (1) A mechanical seal for a water pump, comprising: a rotating ceramic ring and a non-rotating carbon ring; and preventing water from leaking on a sliding surface between the ceramic ring and the carbon ring. 3. A mechanical seal for a water pump, wherein a liquid film is formed on the entire surface of the sliding surface before the first operation. (2) The mechanical seal for a water pump according to claim 1, wherein the liquid of the liquid film is a stock solution of ethylene glycol or an aqueous solution thereof. (3) A liquid film of a hard-to-dry liquid is formed on the entire sliding surface of the mechanical seal in which the rotating ceramic ring and the non-rotating carbon ring are slidably contacted with each other.
A method for forming a mechanical seal for a water pump (forming method), wherein water is supplied and a first operation of the water pump is started.

In the mechanical seal for a water pump of the above (1), a liquid film is formed on the entire sliding surface between the ceramic ring and the carbon ring before the first operation of the water pump. Occasionally, the sliding surface is fully lubricated, preventing carbon sticking, surface roughening, ring dance, and accumulation of antifreeze components, etc., which occurred when there were dry parts, and water leakage through the mechanical seal sliding surface. Is prevented. Due to the liquid film, direct contact between the ceramic ring and the carbon ring is suppressed, and water filled in the impeller portion of the pump is easily taken into the sliding surface. In the mechanical seal for the water pump of the above (2), the liquid film is hardly dried because the liquid of the liquid film is a stock solution of ethylene glycol or an aqueous solution thereof. And the lubrication of the sliding surface is maintained. In the method (3) of forming a mechanical seal for a water pump (forming method), the first operation of the pump is started after a liquid film of a liquid that is difficult to dry is formed on the entire sliding surface of the mechanical seal. The moving surface is lubricated over the entire surface, preventing carbon adhesion, surface roughening, ring dance, accumulation of antifreeze components, etc. that occurred when there was a dry part, and preventing water leakage through the sliding surface of the mechanical seal Is done.

[0006]

1 and 2 show a mechanical seal for a water pump according to an embodiment of the present invention and a structure in the vicinity thereof. As shown in FIG. 1, a water pump for an internal combustion engine cooling water system is mounted on a housing 10, a pump shaft (also referred to as a bearing shaft) 9 rotatably supported on the housing 10 via a bearing 11, and attached to the pump shaft 9. And a pulley (not shown, rotation of the engine crankshaft is transmitted to the pulley via a belt) attached to an end of the pump shaft 9 opposite to the impeller 8, and the impeller 8.
And a mechanical seal for a water pump that blocks the space in which the bearing 11 is disposed.

The mechanical seal for a water pump has a rotating ceramic ring 6 and a non-rotating carbon ring 1. The ceramic ring 6 is a ceramic ring having a substantially rectangular cross section, and is held by an impeller 8 via a gasket 7 made of rubber, for example.
It rotates with the impeller 8. The carbon ring 1 is a ring made of carbon, which is movable in the axial direction but is non-rotating, and is pressed against the ceramic ring 6 in the axial direction. The carbon ring 1 has a protruding portion 1a protruding toward the ceramic ring 6, and the front end surface of the protruding portion 1a is in surface contact with the ceramic ring 6 so as to be able to rotate and slide.
The width of the protruding portion 1a in the radial direction of the pump is
Smaller than the radial width of the pump. The protrusion 1a is in contact with the center of the width of the ceramic ring 6 in the radial direction of the pump. The outside of the ceramic ring 6 and the carbon ring 1 is a space filled with engine cooling water, and the inside is an air space. The rotary sliding surface 12 between the ceramic ring 6 and the carbon ring 1 forms a mechanical seal surface.

An annular cartridge 5 is provided outside the pump shaft 9. The cartridge 5 includes a portion 5a extending along the outer peripheral surface of the pump shaft 9 and a portion 5a.
A portion 5b rising radially outward from one end of the portion, a portion 5c extending from the outer end of the portion 5b in a direction approaching the carbon ring 1 in parallel with the pump shaft 9, and a portion rising radially outward from the end of the portion 5c. 5d.
The carbon ring 1 is disposed radially outward of an end of the portion 5a farther from the portion 5b, and is movable in the axial direction with respect to the portion 5b. The part 5c is fitted on the inner surface of the housing 10, and the part 5d is engaged with the end of the housing 10.

A rubber bellows 2 is arranged outside the portion 5a. The bellows 2 includes a first portion 2a in contact with the carbon ring 1, a second portion 2b in contact with the portion 5b, and a connecting portion 2c extending between the first portion 2a and the second portion 2b. And First part 2
A compression spring 4 is arranged between a and the second portion 2b, and the carbon ring 1 is pressed against the ceramic ring 6 by the bias of the spring. Spring 4
A spring holder 3 is disposed on the first portion 2a side of the bellows 2.

A material that is harder to dry than pure water (a non-drying material) over the entire sliding surface 12 between the carbon ring 1 and the ceramic ring 6 (over the entire sliding surface 12 between the protrusion 6a and the ceramic ring 6). The liquid film 13 (shown in FIG. 2) is formed of a material such as a stock solution of ethylene glycol or an aqueous solution of ethylene glycol. The formation of the liquid film 13 is performed before the first operation of the water pump. Ethylene glycol is a main component of the antifreeze liquid of the engine cooling water filled in the pump, and does not generate precipitates in a high temperature state, so that it is suitable for use as a material of the liquid film 13.
The formation of the liquid film 13 on the sliding surface 12 is performed before the start of the pump operation. The liquid film 13 may be formed by applying liquid to the entire end surface of the protrusion 6a, applying liquid to the entire end surface of the ceramic ring 6 on the side in contact with the protrusion 6a, or by coating the entire end surface of the protrusion 6a with the ceramic ring. The liquid may be applied to both the entire end face of the side contacting with the protruding portion 6a of 6.

Next, a method of forming (forming) a mechanical seal for a water pump according to an embodiment of the present invention will be described with reference to FIGS. In the method of forming the mechanical seal for the water pump according to the embodiment of the present invention, it is difficult to dry the entire surface of the sliding surface 12 of the mechanical seal in which the rotating ceramic ring 6 and the non-rotating carbon ring 1 are slidably contacted. A liquid film 13 of the liquid is formed, and then the water pump is filled with water (engine cooling water, industrial water, etc., which is filled at the time of the test), and the first operation of the water pump is started.
Having a process. The liquid of the liquid film 13 is made of a material that is harder to dry than pure water (a non-drying material), for example, a stock solution of ethylene glycol or an aqueous solution of ethylene glycol.

Next, the operation of the mechanical seal for a water pump according to the embodiment of the present invention and the method of forming the same (forming method) will be described. FIG. 3 shows a roughened surface of the carbon ring 1 'and the ceramic ring 6' after durability in a conventional water pump. In the figure, the two-dot chain line shows the initial state. After durability, the carbon ring 1 'wears out,
The inner corners in the radial direction are greatly worn and missing, and carbon adheres to the surface of the ceramic ring 6 ′.
Antifreeze components accumulate and cause surface roughness.

[0013] Although the adhesion of carbon, the dance of the ring, and the deposition of the antifreeze component are different to those in FIG. 3, when the pump is operated with the sliding surface 12 in a dry state,
Occurs within minutes. Since the carbon ring 1 is pressed against the ceramic ring 6 by a spring bias, even if the pump is filled with water, water does not enter the sliding surface 12 or does not easily enter the pump. When the test is performed and the pump is rotated, the surface of the sliding surface 12 is conventionally or is likely to be roughened.

However, in the embodiment of the present invention, since the liquid film 13 is formed on the entire sliding surface 12 before the pump operation is started, and since the liquid film 13 is hard to dry, the liquid film 13 is The membrane 13 is not dry and the sliding surface 12 is in a lubricated state.
(Including adhesion of carbon to the sliding surface of the ceramic ring, deposition of antifreeze components, etc.) does not occur. The reason that the surface roughness does not occur is that the liquid film 13 does not cause direct contact between the carbon ring 1 and the ceramic ring 6, and does not receive the high temperature of frictional heat generated by rotation in the direct dry contact state, and the engine cooling water This is because the intrusion into the sliding surface 12 is performed relatively smoothly.

[0015]

According to the mechanical seal for a water pump according to the first aspect of the present invention, the entire surface of the sliding surface between the ceramic ring and the carbon ring is provided before the first operation of the water pump.
Since the liquid film is formed, the sliding surface is completely lubricated when the water pump is running, preventing carbon adhesion, surface roughening, ring dance, and accumulation of antifreeze liquid components that occurred when there was a dry part. Water leakage through the sliding surface of the mechanical seal can be prevented. According to the mechanical seal for a water pump of claim 2, since the liquid of the liquid film is a stock solution of ethylene glycol or an aqueous solution thereof, it is difficult to dry,
Lubrication of the sliding surface can be maintained. In the method for forming a mechanical seal for a water pump according to the third aspect (forming method), the first operation of the water pump is started after a liquid film of a liquid that is difficult to dry is formed on the entire sliding surface of the mechanical seal. During operation, the sliding surface is lubricated over the entire surface, preventing carbon adhesion, surface roughening, ring dance, accumulation of antifreeze components, etc., which occurred when there was a dry part, and water passing through the mechanical seal sliding surface. Leakage can be prevented.

[Brief description of the drawings]

FIG. 1 is a sectional view of a mechanical seal for a water pump according to an embodiment of the present invention.

FIG. 2 is a sectional view of a sliding surface between a carbon ring and a ceramic ring of FIG.

FIG. 3 is a cross-sectional view of a sliding surface of a carbon ring and a ceramic ring after pump durability in a case where a liquid film is not formed (conventional), and a cross-section immediately therearound.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Carbon ring 1a Projection 2 Bellows 3 Spring holder 4 Spring 5 Cartridge 6 Ceramic ring 7 Gasket 8 Impeller 9 Pump shaft (bearing shaft) 10 Housing 11 Bearing 12 Sliding surface 13 Liquid film

Claims (3)

[Claims] 1. A mechanical seal for a water pump, comprising: a rotating ceramic ring and a non-rotating carbon ring; and preventing water from leaking on a sliding surface between the ceramic ring and the carbon ring. A mechanical seal for a water pump, wherein a liquid film is formed on the entire sliding surface before the first operation of the water pump. 2. The mechanical seal for a water pump according to claim 1, wherein the liquid of the liquid film is a stock solution of ethylene glycol or an aqueous solution thereof. 3. A liquid film of a hard-to-dry liquid is formed on the entire sliding surface of a mechanical seal in which a rotating ceramic ring and a non-rotating carbon ring are slidably contacted with each other. And starting the first operation of the water pump.