JPS63664B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mechanical seal for a water pump.

Generally, mechanical seals for water pumps installed in engine cooling systems have a seat ring and a driven ring in sliding contact, and the sliding surface prevents water on the outer circumference from leaking into the atmosphere on the inner circumference. There is. In mechanical seals for water pumps, the lubricating fluid on the sliding surface is water, so the sliding surface is The sliding conditions were poor and stucking was likely to occur, resulting in noise. In the past, this noise was not considered a big problem because it was relatively small compared to the noise of other engines, etc., but as efforts have been made to reduce the noise of engines, etc., it is especially important to reduce engine speeds at low speeds where ambient noise is low. It has become a problem in the area.

In view of these circumstances, the present invention provides a mechanical seal for a water pump that can reduce noise.

That is, the present invention includes a seat ring and a driven ring that is in sliding contact with the seat ring, and prevents water on the outer circumferential side from leaking into the atmosphere on the inner circumferential side at the sliding contact surface of the seat ring and the driven ring. In the mechanical seal for a water pump that prevents sliding contact, the inner part opens and communicates with the inner peripheral side, and the outer part extends and closes toward the rear side of the relative rotation of both rings, and the sliding contact surface of the other ring is closed. A thread groove is formed in contact with each other to suppress adhesion of both sliding contact surfaces and improve sealing performance, and the outer portions of the sliding contact surfaces are slightly separated at room temperature, and both the rings are
When both rings are thermally deformed, the outer portions of the sliding surfaces are made of a material that deforms in a direction that separates them further apart, and water on the outer circumferential side is introduced into the separated portions.

According to the above configuration, when the two sliding surfaces rotate relative to each other, water is introduced into the outer periphery of the two sliding surfaces to improve the lubrication conditions between the two sliding surfaces and to cool both sliding surfaces, thereby reducing noise generation. Moreover, since the thread grooves suppress adhesion between the two sliding contact surfaces, the generation of noise can also be suppressed in this respect. Water that is introduced to the outer circumference of both sliding contact surfaces and tries to leak to the inner circumference can be pushed back to the outer circumference by the thread groove, so compared to ordinary mechanical seals for water pumps. This can reduce the amount of leakage.

The present invention will be described below with reference to the illustrated embodiments.
In FIG. 1, 1 is a casing of a water pump, and 2 is a rotating shaft inserted into a cylindrical part 1a of the casing 1 and rotatably supported by a bearing (not shown) provided in the cylindrical part 1a. The left end of the rotating shaft 2 is linked to an engine as a drive source via a pulley and a belt (not shown).

A mechanical seal 3 is provided at the right end of the cylindrical portion 1a, and this mechanical seal 3 rotates together with a driven ring 4 that can be displaced in the axial direction of the rotating shaft 2, but not in the axial direction. A fixed seat ring 5 is provided. The driven ring 4 is an inner cylindrical portion 6a that constitutes a part of the support member 6.
A shaft is fitted on the outer periphery of the tip of the inner cylindrical portion 6a so as to be reciprocally movable along the axial direction thereof, and a shaft provided on the outer periphery of the inner cylindrical portion 6a is fitted in the axial groove 4a provided on the inner periphery of the driven ring 4. By engaging the directional protrusion 6b,
This prevents the two from rotating relative to each other. The support member 6 includes a wall portion 6c extending radially outward from the left end of the inner cylindrical portion 6a, an outer cylindrical portion 6d folded back to the right from the outer periphery of the wall portion 6c, and a radial radius from the outer cylindrical portion 6d. It has a flange portion 6e bent outward in the direction, and by fitting the outer cylindrical portion 6d into the cylindrical portion 1a of the casing 1 via the seal member 7, the sealing performance of that portion is improved. The driven ring 4 is fixed with respect to the rotating direction.

One end of a sealing member 8 is bonded to the right end surface of the wall 6c of the supporting member 6 with adhesive, and the other end of the sealing member 8 is attached to the left end of the driven ring 4 with the intermediate portion curved. By adhering to the surface, the sealing performance between the support member 6 and the seat ring 4 is maintained. By elastically loading a spring 9 between both ends of this sealing member 8, the driven ring 4
is brought into elastic contact with the seat ring 5. This seat ring 5 is attached via a floating gasket 11 in a recess 10a formed in a rotor 10 fixed to the rotary shaft 2 for performing a pump action, so that the seat ring 5 rotates integrally with the rotary shaft 2. That's what I do. Note that, contrary to the illustrated embodiment, a driven ring 4 that is displaceable in the axial direction with respect to the rotating shaft 2 is provided on the rotating shaft 2 so that it can rotate integrally therewith, and a seat ring 5 is attached to the casing 1. It may be fixed.

In the water pump having the above configuration, when the rotary shaft 2 is rotationally driven by an engine (not shown), the rotor 10 integrated therewith rotates to supply water to each cooling section in the engine. At this time, the water is sealed by the seal members 7 and 8 as well as by the sliding surfaces of the driven ring 4 and the seat ring 5 of the mechanical seal 3.

However, the sliding surface of the driven ring 4 is formed as a tapered surface with an inner height that slightly protrudes from the inner peripheral side than the outer peripheral side. When it is 4 mm, it is about 0.3 to 1.0 μm. Note that this sliding surface may be a spherical surface protruding toward the seat ring 5 side.

Further, as shown in FIG. 2, the sliding surface of the driven ring 4 has thread grooves 12 at equal intervals on its inner circumference.
is formed. The inner side of each thread groove 12 opens and communicates with the inner peripheral side of the driven ring 4, and the outer side extends rearward in the direction of rotation of the driven ring 4 relative to the seat ring 5 and closes at the middle part of the sliding surface. There is. Therefore, a flat land portion 13 without grooves and continuous in the circumferential direction is formed on the outer peripheral portion of the sliding surface. When the driven ring 4 rotates, the inner circumferential side of the driven ring 4 is thermally deformed to an inner height that projects further in the axial direction than the outer circumferential side due to the frictional heat caused by the sliding contact between the driven ring 4 and the seat ring 5. Such thermal deformation can be obtained by forming the driven ring 4 from a carbon material or the like. Further, the other seat ring 5 may be made of a stainless steel material, an alumina sintered body, or the like, which has less thermal deformation. In addition, in a water pump for an engine cooling system, the fact that water is heated by the engine also promotes the above-mentioned thermal deformation.

In such a configuration, when the driven ring 4 is at room temperature, that is, when the rotation is stopped, the sliding surfaces of both rings 4 and 5 are in contact with the outer circumferential portions being slightly separated, but the outer circumferential portions are slightly apart. Therefore, it is possible to substantially prevent water from flowing into the gap, thereby preventing water from leaking when the rotation is stopped.

When the driven ring 4 is rotated, water flows between the sliding surfaces due to the vibration of the driven ring 4 during rotation, the viscosity of water, etc., which improves the lubrication conditions of that part and improves the sliding surface. Cools the contact surface, thereby suppressing noise generation. Furthermore, when the rotation of the driven ring 4 continues and both rings 4 and 5 are heated by heating the water, the driven ring 4 is thermally deformed and becomes inner height as described above. , water can more easily flow between the two sliding surfaces, ensuring good lubrication conditions and cooling effects even at high temperatures, and suppressing noise generation.

The yarn grooves 12 capture water leaking beyond the land portions 13 with increased spacing, and the pumping action of the rotation pushes the water back toward the outer periphery of the driven ring 4, so that the spacing increases. Even if it is enlarged, the amount of water leakage does not increase, and as shown in the experimental results later, the amount of leakage can be reduced compared to the conventional method.

Furthermore, the thread grooves 12 act not only on the water existing between the sliding surfaces, but also on the sliding surface of the seat ring 5, which is a mating member. That is, since the lubrication conditions between the driven ring 4 and the seat ring 5 are poor, even if the land portion 13 is separated from the sliding surface of the mating material due to thermal deformation, the inner thread groove 12 portion will not slide. Adhesion occurs due to the contact surface, causing sticking and causing abnormal noise, but the thread grooves 12 are designed to suppress the occurrence or growth of adhesion and prevent the generation of abnormal noise. Conceivable. In addition, the thread groove 12 stores foreign matter and abrasion powder,
It prevents surface roughness and an increase in sliding resistance due to the presence of foreign matter and abrasion powder between sliding surfaces, and also prevents adhesion from occurring due to surface roughness, making it unique from this point of view. It functions to prevent the generation of sound.

Next, Fig. 3 shows the results of a noise test on mechanical seals. Fig. 3 a shows the example of Fig. 2, and Fig. 3 b shows the conventional seal without thread grooves for comparison. Fig. 3c shows the experimental results with the mechanical seal itself omitted.
In this experiment, the driven ring 4 was thermally deformed.

In this experiment, the rotary shaft 2 was rotated by a motor (250 rpm) with or without a mechanical seal installed in the casing 1, and the casing 1 with the mechanical seal installed actually discharged water as a water pump. Approximately 150
Sound pressure was measured with a sound level meter set at a distance of mm, and frequency analysis was performed. At the same time, the overall noise of each was measured and the results are shown as mesh bar graphs at the right end of each figure.

As can be understood from the experimental results shown in Figures 3a to 3c, the sound pressure associated with the mechanical seal is shown by the shaded areas in Figures 3a and b, and from this result as well as the above noise result, the sound pressure involved in the mechanical seal is It is judged that no substantial noise is generated.

FIG. 4 shows the amount of water leakage measured under the following experimental conditions for the two types of mechanical seals described above. This experiment consists of 9 springs for each mechanical seal.
The results of 10 measurements each with different repulsive forces are shown.

(Experiment conditions) Γ Testing machine: Physical testing machine Γ Rotation speed: 2000 rpm Γ Time: 100 hoursΓ Sealing fluid: Water (80℃) Γ Sealing pressure: 1.5Kg/cm ^2As shown in the experimental results in Figure 4 Compared to conventional mechanical seals, the mechanical seal according to the present invention has a smaller maximum leakage amount, an average leakage amount, and a smaller range between the maximum and minimum leakage amounts, and has excellent sealing performance.

Next, FIGS. 5a and 5b show the results of a noise test conducted with the driven ring 4 substantially free from thermal deformation; FIG. In this figure, the middle and high amounts are set to 0.5μm, and the same figure b
For comparison, FIG. 2 is the same as the embodiment shown in FIG. 2, in which the yarn grooves 12 are formed, with the medium height being set to 0.

In this test, the mechanical seal was installed in the water pump in the same way as in the case shown in Figure 3, and the sound level was measured using a sound level meter set at a distance of about 150 mm under the following experimental conditions.

(Experiment conditions) Γ Testing machine: Physical testing machine Γ Rotation speed: 200 rpm Γ Measurement time: Measured after 100 hours Γ Sealing fluid: Water (50℃) Γ Sealing pressure: Atmospheric pressure From the test results in Figure 5 a and b As is clear,
In a state where the driven ring 4 is not substantially thermally deformed, if the driven ring 4 is not shaped in advance into a mid-height shape, squealing will result.

In the present invention, when the temperature increases due to the heat of sliding, more water is introduced to cool the sliding surface, which acts to suppress the amount of deformation and maintain a certain amount of cooling effect. This will further reduce the variation in Furthermore, even if there is some leakage at the outer circumferential portion, sealing performance can be ensured by the action of the thread grooves on the inner circumferential side.

In the above embodiment, the thread groove 12 is provided in the driven ring 4, but it may be provided in the seat ring 5. When a thread groove is provided in the seat ring 5, the materials of the seat ring 5 and the driven ring 4 are reversed from those in the above embodiment, and the areas of the end surfaces of both rings 4, 5, which are the sliding surfaces, are also reversed. do it. Further, the depth, width, number, etc. of the thread grooves 12 can be determined as appropriate depending on the conditions of use, etc., and the direction in which the thread grooves 12 are formed can be set approximately in the radial direction according to these settings. Can be done.

As described above, according to the present invention, it is possible to reduce the noise of a mechanical seal for a water pump.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing one embodiment of the present invention, and FIG.
The figure is a front view of the seat ring in Figure 1, and Figure 3 a~
Figure c shows the results of sound pressure and noise measurements in a state where thermal deformation occurs, Figure 4 shows the results of measuring the amount of leakage, and Figures 5a and b show the results in a state where no thermal deformation occurs. FIG. 3 is a diagram showing the results of measuring sound pressure and noise. DESCRIPTION OF SYMBOLS 1... Casing, 2... Rotating shaft, 3... Mechanical seal, 4... Driven ring, 5... Seat ring, 12... Yarn groove, 13... Land portion.

Claims (1)

[Claims] 1. A seat ring and a driven ring that slides on the seat ring, and water on the outer circumference leaks into the atmosphere on the inner circumference at the sliding contact surface between the seat ring and the driven ring. In a mechanical seal for a water pump, the inner part opens and communicates with the sliding contact surface toward the inner periphery, and the outer part extends and closes toward the rear side of the relative rotation of both rings, and the sliding contact surface of the other A thread groove is formed that slides into contact with the ring to suppress adhesion between the two sliding contact surfaces and improve sealing performance, and the outer portion of the sliding contact surface is slightly separated at room temperature, and the two rings are connected to each other.
A mechanical seal for a water pump, characterized in that when both rings are thermally deformed, the outer portions of the sliding surfaces are made of a material that deforms in a direction that separates them further, and water on the outer peripheral side is introduced into the separated portions. .