JP7211755B2 - sealing device - Google Patents

Description

The present invention relates to a sealing device that seals between a rotating shaft connected to a motor and a housing.

Generally, in EVs (Electric Vehicles) and HVs (Hybrid Vehicles), an oil seal is installed between the rotating shaft of the motor and the housing to prevent leakage of the lubricant sealed inside the machine to the outside of the machine. A sealing device is provided.
In such EVs and HVs, electromagnetic noise is generated by the induced current generated in the motor, which may affect AM radios of car audio systems.

Patent Document 1, which is an example of the prior art, discloses an electric motor housing and a rotating shaft in the electric motor in a power transmission system of an electric vehicle for the purpose of reducing the generation of electromagnetic noise from the electric motor. , so that the electromagnetic noise induced in the rotating shaft is released to the metal motor housing.
In particular, in FIG. 4 of Patent Document 1, the electric motor housing (14) and the rotating shaft (18) in the electric motor (10) are electrically connected by an oil seal (86) made of conductive rubber. , discloses a technique for releasing electromagnetic noise induced in a rotating shaft to a metal motor housing.

JP-A-2000-244180

According to the prior art described above, it is possible to ensure electrical continuity between the rotating shaft connected to the motor and the housing, but there is room for improvement in terms of volume resistivity.

SUMMARY OF THE INVENTION The present invention has been made in view of the above, and it is an object of the present invention to provide smooth conduction between a rotating shaft connected to a motor and a housing at a low cost and in a small space.

SUMMARY OF THE INVENTION The present invention, which solves the above-mentioned problems and achieves its objects, is a sealing device arranged between a rotating shaft connected to a motor and a housing to seal the interior and exterior of the machine, wherein the sealing device slides on the rotating shaft. a conductive elastic body portion having a lip movably in contact with the rotating shaft and disposed between the rotating shaft and the housing to prevent foreign matter from entering from the outside of the machine and to seal the lubricating material inside the machine; a conductive reinforcing ring integrally formed with the elastic body portion and in contact with the inner peripheral surface of the housing; The sealing device has a second conductive surface contacting the reinforcing ring on the side thereof, and the electrical conductivity between the first conductive surface and the second conductive surface is higher than that of the elastic body portion.

In the sealing device configured as described above, it is preferable that the first conducting surface is surrounded by a joint surface between the reinforcing ring and the elastic body portion.

In the sealing device configured as described above, the base metal of the reinforcing ring is in contact with the elastic body portion on the first conducting surface, and the base metal of the reinforcing ring is in contact with the housing on the second conducting surface. is preferred.

ADVANTAGE OF THE INVENTION According to this invention, it is effective in the ability to perform the conduction|electrical_connection between the rotating shaft and housing connected to the motor smoothly at low cost and space-saving.

It is a cross-sectional view showing a mounting state of the oil seal, which is the sealing device according to the embodiment. FIG. 4 is a diagram illustrating the flow of an induced current from a rotating shaft to a housing in the oil seal that is the sealing device according to the embodiment; FIG. 4 is a diagram showing an example of a portion of the reinforcing ring where the bare metal is exposed in the oil seal, which is the sealing device according to the embodiment.

Embodiments of the present invention will be described below with reference to the drawings.
However, the present invention is not to be construed as limited by the description of the following embodiments.

<Embodiment>
FIG. 1 is a cross-sectional view showing an installed state of an oil seal 1, which is a sealing device according to this embodiment.
An oil seal 1 shown in FIG. 1 is a sealing device arranged between a rotary shaft 41 and a housing 42 to seal an interior A and an exterior B of the machine.
A rotating shaft 41 shown in FIG. 1 is connected to a motor (not shown) to rotate, and a housing 42 is grounded.
In addition, the oil seal 1 shown in FIG. Conduction between 41 and housing 42 can be performed smoothly.

The seal portion 10 includes a reinforcing ring 20 and an elastic body portion 30, and the reinforcing ring 20 and the elastic body portion 30 are integrally formed.
Further, the seal portion 10 is mounted on an inner peripheral surface 42a, which is a surface on the inner peripheral side (in the direction of arrow d) of the housing 42. As shown in FIG.

The reinforcing ring 20 is a conductive metal ring made of metal centered on the axis x of the rotating shaft 41 .
Examples of materials for the reinforcing ring 20 include stainless steel and cold rolled steel (SPCC).
Further, the reinforcing ring 20 can be formed by pressing or forging.

The elastic body portion 30 is a substantially annular conductive elastic body made of an elastic material centered on the axis x of the rotating shaft 41 .
Synthetic rubber can be exemplified as the material of the elastic body portion 30 .
Examples of synthetic rubbers include nitrile rubber (NBR), hydrogenated nitrile rubber (H-NBR), acrylic rubber (ACM) and fluororubber (FKM).

Also, the elastic body portion 30 can be formed by crosslinking using a mold.
More specifically, the elastic body portion 30 is formed by disposing an uncrosslinked rubber material in contact with the reinforcing ring 20 disposed in the mold, and heating the closed space in the mold while being sandwiched between the molds. By applying pressure and bridging, it is integrally formed with the reinforcing ring 20 .
An adhesive is applied between the reinforcing ring 20 and the elastic body portion 30 .

The reinforcing ring 20 includes a cylindrical portion 20a, an outer peripheral disc portion 20b, a tapered portion 20c, and an inner peripheral disc portion 20d. The portion 20d is integrally formed.
Further, the outer peripheral disk portion 20b, the tapered portion 20c, and the inner peripheral disk portion 20d form a generally S-shaped flange portion as a whole.

The cylindrical portion 20a is a cylindrical portion that extends in a direction substantially parallel to the axis x, and is fitted in contact with the inner peripheral surface 42a of the housing 42 .
The outer peripheral disk portion 20b is a hollow disk-shaped portion formed from the outer (arrow a direction) end of the cylindrical portion 20a toward the inner peripheral side (arrow d direction).
The tapered portion 20c is a hollow disk-shaped portion formed from the inner peripheral side (arrow d direction) end of the outer peripheral disk portion 20b toward the inner peripheral side (arrow d direction) and inward (arrow b direction). is.
The inner peripheral disk portion 20d is a hollow disk-shaped portion formed further toward the inner peripheral side (arrow d direction) from the inner peripheral side (arrow d direction) end of the tapered portion 20c.
The cylindrical portion 20a may have a shape that bulges toward the outer peripheral side (in the direction of the arrow c) in the unmounted state.

In addition, before mounting the reinforcing ring 20, the base metals of the outer contact surface 20d1 of the inner peripheral disk portion 20d and the outer peripheral surface 20a2 of the cylindrical portion 20a are exposed by mechanical or chemical means.
This is because part of the adhesive applied between the reinforcing ring 20 and the elastic body portion 30 also remains on the outer peripheral surface 20a2 of the reinforcing ring 20, and the adhesive obstructs the conduction. .
Here, examples of mechanical means include polishing and cutting, and examples of chemical means include immersion in a solution capable of removing the adhesive.
Alkaline detergents or solvents can be exemplified as solutions capable of removing such adhesives.
As a result, the base metal of the reinforcing ring 20 is brought into contact with the elastic body portion 30 on the outer contact surface 20d1 to ensure conduction between the reinforcing ring 20 and the elastic body portion 30, and the base metal of the reinforcing ring 20 contacts the housing 42 on the outer peripheral surface 20a2. The conduction between the reinforcing ring 20 and the housing 42 is ensured by contacting the .

1, the contact surface between the base metal of the reinforcing ring 20 and the elastic member 30 is not limited to the outer contact surface 20d1 shown in FIG. It is preferably surrounded by a joint surface.
If the contact surface between the base metal of the reinforcing ring 20 and the elastic member 30 is not surrounded by the joint surface between the reinforcing ring 20 and the elastic member 30, the reinforcing ring 20 and the elastic member 30 are separated. This is to prevent this.

The elastic body portion 30 includes lip covering portions 30a, 30b, 30c, 30d, a lip waist portion 30e, and lips 31, 32, 33. is formed integrally with the reinforcing ring 20 so as to cover a part of and from the inner peripheral side (direction of arrow d).

The lip covering portion 30a covers a part of the cylindrical portion 20a of the reinforcing ring 20 on the outer peripheral side (in the direction of the arrow c).
The lip covering portion 30b covers the outer disk portion 20b of the reinforcing ring 20 from the outside (in the direction of arrow a).
The lip covering portion 30 c covers the tapered portion 20 c of the reinforcing ring 20 and is the base of the lip 31 .
The lip covering portion 30d covers the inner peripheral disk portion 20d of the reinforcing ring 20 from the outside (in the direction of arrow a).
The lip waist portion 30 e is the base portion of the lips 32 and 33 located near the inner peripheral side (arrow d direction) end of the inner peripheral disk portion 20 d of the reinforcing ring 20 .
The lip 31 is slidably in contact with a structure (not shown), the lips 32 and 33 are slidably in contact with the rotating shaft 41, and the lips 31 and 32 prevent foreign matter from entering the machine from the outside B to the inside A. While restraining, the lip 33 prevents the lubricant in the machine A from leaking to the outside B of the machine.
If the elastic member 30 can prevent the lubricant from leaking from the inside A to the outside B while suppressing foreign matter from entering the inside A from the outside B, the lips 31, 32, . 33 may not be provided, and the elastic body portion 30 may be provided with at least one lip.

FIG. 2 is a diagram for explaining the flow of induced current from the rotating shaft 41 to the housing 42 in the oil seal 1, which is the sealing device according to this embodiment.
Here, the surface where the reinforcing ring 20 on the rotary shaft 41 side and the lip waist portion 30e are in contact is defined as a first conductive surface 101, and the surface where the reinforcing ring 20 on the housing side and the housing 42 are in contact is defined as a second conductive surface 102. and
The base metal of the reinforcing ring 20 is in contact with the elastic body portion 30 on the first conducting surface 101 , and the base metal of the reinforcing ring 20 is in contact with the housing 42 on the second conducting surface 102 .
As shown in FIG. 2, the induced current generated by the motor (not shown) connected to the rotating shaft 41 flows from the lips 32 and 33 of the elastic body 30 to the lip waist portion 30e, and the current reaching the lip waist portion 30e The current flows from the first conductive surface 101 to the reinforcing ring 20, which has a lower volume resistivity than the elastic body portion 30, that is, has a higher conductivity, and flows through the reinforcing ring 20 from the second conductive surface 102 to the housing 42. .

As described above, in FIG. 1, the contact surface between the base metal of the reinforcing ring 20 and the elastic member 30 is surrounded by the joint surface between the reinforcing ring 20 and the elastic member 30, so that the first conductive surface 101 is surrounded by the joint surface between the reinforcing ring 20 and the elastic body portion 30 .
With such a configuration, separation between the reinforcing ring 20 and the elastic body portion 30 can be prevented.

In the conventional configuration, since the induced current generated in the motor flows through the elastic body 30 from the rotary shaft 41 to the housing 42, there is a problem that the volume resistivity of the elastic body 30 is high.
As a result, electromagnetic noise is generated by this induced current, and there is a possibility that the AM radio of the car audio system is affected.
However, as described above, the volume resistivity of the induced current can be lowered by providing the conduction path via the reinforcing ring 20 .
Since the conductive path can be provided by exposing the base metal of the existing reinforcing ring 20, the conductive path can be secured at low cost and in a small space.

In this embodiment, the base metal of the reinforcing ring 20 is exposed by mechanical means or chemical means, but the present invention is not limited to this.
Conduction may be ensured by covering the exposed portion of the base metal of the reinforcing ring 20 with a masking tape before applying the adhesive, and then removing the masking tape before mounting.
By using masking tape, continuity can be ensured without using mechanical and chemical means.

In the present embodiment, the exposed portion of the base metal of the reinforcing ring 20 is limited to a specific portion as long as it is the contact surface where the inner peripheral disk portion 20d and the elastic body portion 30 come into contact as described above. not to be

FIG. 3 is a diagram showing an example of a portion of the reinforcing ring 20 where the bare metal is exposed in the oil seal 1, which is the sealing device according to the present embodiment.
FIG. 3 shows an outer contact surface 20d1, an inner peripheral contact surface 20d2, and an inner contact surface 20d3.
The outer contact surface 20d1 is a contact surface where the inner peripheral disc portion 20d and the elastic body portion 30 come into contact with each other on the outer side of the inner peripheral disc portion 20d.
The inner peripheral side contact surface 20d2 is a contact surface where the inner peripheral side disc portion 20d and the elastic body portion 30 come into contact with each other on the inner peripheral side of the inner peripheral side disc portion 20d.
The inner contact surface 20d3 is a contact surface where the inner peripheral disk portion 20d and the elastic body portion 30 come into contact with each other inside the inner peripheral disk portion 20d.

When the base metal of the reinforcing ring 20 is exposed on the outer contact surface 20d1, the outer contact surface 20d1 is surrounded by the joint surface between the reinforcing ring 20 and the elastic body portion 30, so that the bonding strength is high, and during the rotation operation Since these positions are less susceptible to the movement of the lips 31, 32, and 33, the adhesive strength between the inner peripheral disk portion 20d and the elastic body portion 30 can be maintained high.

When the bare metal of the reinforcing ring 20 is exposed on the inner contact surface 20d2, the inner contact surface 20d2 is affected by the movement of the lips 31, 32, and 33 during the rotation, but the reinforcing ring 20 and the elastic body are in contact with each other. Since it is surrounded by the joint surface with the part 30, the adhesive strength is strong.

When the bare metal of the reinforcing ring 20 is exposed on the inner contact surface 20d3, the inner contact surface 20d3 is affected by the movements of the lips 31, 32, and 33 during the rotational operation, and the reinforcing ring 20 and the elastic body portion 30 are joined together. Not bounded by faces.
Therefore, the exposed portion of the base metal of the reinforcing ring 20 is preferably the inner contact surface 20d2 rather than the inner contact surface 20d3, and the outer contact surface 20d1 is more preferable than the inner contact surface 20d2.

As described above, according to the present embodiment, electrical continuity between the rotating shaft connected to the motor and the housing can be achieved smoothly at low cost and in a small space.

1 Oil seal 10 Seal portion 20 Reinforcing ring 20a Cylindrical portion 20a2 Outer peripheral surface 20b Outer peripheral disk portion 20c Taper portion 20d Inner peripheral disk portion 20d1 Outer contact surface 20d2 Inner peripheral contact surface 20d3 Inner contact surface 30 Elastic body portions 30a, 30b , 30c, 30d lip covering portion 30e lip waist portions 31, 32, 33 lip 41 rotating shaft 42 housing 42a inner peripheral surface 101 first conducting surface 102 second conducting surface

Claims (4)

A sealing device arranged between a rotating shaft connected to a motor and a housing to seal the inside and outside of the machine,
A conductive elastic material having a lip slidably contacting the rotating shaft and disposed between the rotating shaft and the housing to seal the lubricating material inside the device while suppressing the intrusion of foreign matter from the outside of the device. body and
a conductive reinforcing ring formed integrally with the elastic body portion and in contact with the inner peripheral surface of the housing ;
An adhesive applied between the elastic body portion and the reinforcing ring ,
The reinforcing ring has a first conductive surface in contact with the elastic body portion on the rotating shaft side and a second conductive surface in contact with the housing on the housing side,
conductivity between the first conductive surface and the second conductive surface is higher than that of the elastic body;
A sealing device in which no adhesive is applied to the first conductive surface between the elastic body portion and the reinforcing ring . conductivity between the first conductive surface and the second conductive surface is higher than that of the elastic body;
2. The sealing device of claim 1, wherein said second conductive surface between said housing and said reinforcing ring is free of adhesive. 3. A sealing device according to claim 1, wherein said first conductive surface is surrounded by a joint surface between said reinforcing ring and said elastic body portion. On the first conductive surface, the base metal of the reinforcing ring is in contact with the elastic body,
4. The sealing device according to any one of claims 1 to 3, wherein the base metal of the reinforcing ring is in contact with the housing on the second conductive surface.

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