JP7720738B2 - sealing device - Google Patents

Description

The present invention relates to a sealing device.

Generally, in EVs (Electric Vehicles) and HEVs (Hybrid Electric Vehicles), a sealing device, which is an oil seal, is provided between the rotating shaft of the motor and the housing to prevent leakage of lubricant sealed inside the vehicle to the outside.
In such EVs and HEVs, electromagnetic noise is generated by induced currents in the motors, raising concerns about adverse effects on electronic devices.

As a related prior art, for example, Patent Document 1 describes an oil seal consisting of a reinforcing ring with a generally L-shaped cross section to which an oil lip and dust lip made of a rubber-like elastic material are bonded, wherein the dust lip is made of woven or nonwoven fabric containing a conductive material, and at least a portion of the mating surface of the reinforcing ring is exposed. Furthermore, it describes how this type of oil seal ensures conductivity between the housing and shaft via the dust lip and reinforcing ring, thereby avoiding the noise generation problem seen when using conventional oil seals.

Patent Document 2 also describes a sealing device arranged between a rotating shaft connected to a motor and a housing to seal the inside and outside of the machine. The sealing device includes a conductive elastic body having a lip that slidably contacts the rotating shaft and is arranged between the rotating shaft and the housing to seal lubricant into the inside of the machine while preventing foreign matter from entering from outside; a conductive reinforcing ring formed integrally with the elastic body and having a conductive surface that contacts the inner surface of the housing; and a conductive metal ring having a first conductive surface that contacts the elastic body on the rotating shaft side and a second conductive surface that contacts the reinforcing ring on the housing side, the conductive metal ring having higher conductivity between the first conductive surface and the second conductive surface than the elastic body. It also describes that this sealing device enables smooth conductivity between the rotating shaft connected to the motor and the housing at low cost and in a space-saving manner.

Japanese Utility Model Application Publication No. 60-167263 Japanese Patent Application Laid-Open No. 2020-60240

The present invention provides a sealing device that can achieve electrical continuity between a rotating shaft and a housing for a long period of time, at low cost, and in a space-saving manner.

The present invention includes the following (1) to (6).
(1) A sealing device that is disposed in a gap between an outer surface of a rotating shaft and an inner surface of a housing having a shaft hole into which the rotating shaft is inserted, and seals the gap,
an annular sleeve tube portion fixed to the outer surface of the rotating shaft and including a fixing surface extending in an axial direction of the rotating shaft and a support surface connected to an end of the fixing surface and extending in a direction approaching an inner surface of the housing;
a ring-shaped conductive part, the outer periphery of which is in contact with the inner surface of the housing and the main surface of which is fixed to the support surface of the sleeve pipe part;
a seal portion including: an annular mounting portion made of an elastic body attached to the inner surface of the housing; a lip portion made of an elastic body that is in slidable contact with the outer surface of the rotating shaft and/or the fixed surface of the sleeve tube portion; a connecting portion made of an elastic body that connects the mounting portion and the lip portion; and a reinforcing ring that is in close contact with the inner surface of the mounting portion and also with the connecting portion, the seal portion preventing foreign matter from entering from the outside and sealing the lubricant inside;
and a sealing device which can electrically connect the rotating shaft and the housing.
(2) The sealing device according to (1) above, wherein the inner circumference of the ring in the conductive portion is in contact with the outer surface of the rotating shaft.
(3) The sealing device according to (1) or (2) above, wherein the conductive portion is made of a conductive nonwoven fabric.
(4) A sealing device according to any one of (1) to (3) above, wherein the conductive portion, the sheath tube portion, and the seal portion are arranged in this order in a gap between the outer surface of the rotating shaft and the inner surface of the housing, from the outer side toward the inner side in the axial direction of the rotating shaft.
(5) A sealing device according to any one of (1) to (4) above, in which the outer periphery of the ring in the conductive portion has a plurality of notches.
(6) A sealing device according to any one of (1) to (5) above, wherein the fixing surface and the support surface in the sleeve pipe portion are substantially perpendicular to each other in a cross section parallel to the axis of the rotating shaft.

The present invention provides a sealing device that can achieve electrical continuity between a rotating shaft and a housing for a long period of time, at low cost, and in a space-saving manner.

1 is a schematic cross-sectional view showing a preferred embodiment of a sealing device of the present invention. 1 is a schematic plan view of a conductive portion of a preferred embodiment of the sealing device of the present invention. FIG.

The present invention will now be described.
the housing has an axial hole into which the rotating shaft is inserted, and the sealing device is disposed in a gap between the outer surface of the rotating shaft and an inner surface that constitutes the axial hole, the housing having the axial hole and sealing the gap, the sealing device including: an annular sleeve tube portion that is fixed to the outer surface of the rotating shaft and has a fixed surface that extends toward the axial center of the rotating shaft and a support surface that is connected to an end of the fixed surface and extends in a direction approaching the inner surface of the housing; a ring-shaped conductive portion whose outer periphery is in contact with the inner surface of the housing and whose main surface is fixed to the support surface of the sleeve tube portion; an annular mounting portion made of an elastic body attached to the inner surface of the housing; a lip portion made of an elastic body that is in slidable contact with the outer surface of the rotating shaft and/or the fixed surface of the sleeve tube portion; a connecting portion made of an elastic body that connects the mounting portion and the lip portion; and a reinforcing ring that is in close contact with the inner surface of the mounting portion and also with the connecting portion, the sealing portion that prevents foreign matter from entering from the outside and seals out the lubricant inside, and the sealing device can provide electrical conductivity between the rotating shaft and the housing.
Such a sealing device will be hereinafter referred to as the "sealing device of the present invention."

The sealing device of the present invention will be described with reference to the drawings.
The sealing device of the present invention shown in the drawings is a preferred embodiment (example), and the sealing device of the present invention is not limited to the embodiment shown in the drawings.

Figure 1 is a schematic cross-sectional view (schematic cross-sectional view) of the sealing device, rotating shaft, and housing of the present invention taken along a direction parallel to the axis ω of the rotating shaft.

In Figure 1, the sealing device 1 of the present invention is disposed in a gap 205 between the outer surface 110 of the rotating shaft 100 and the inner surface 210 that constitutes the shaft hole of a housing 200 having a shaft hole into which the rotating shaft 100 is inserted.

The rotating shaft 100 may be, for example, the motor shaft of a drive motor in an EV (Electric Vehicle) or HEV (Hybrid Electric Vehicle). The rotating shaft 100 is typically rod-shaped (cylindrical), and its cross section is typically circular.

The housing 200 is typically grounded.

The sealing device 1 of the present invention has a seal portion 10, a sleeve tube portion 20, and a conductive portion 30.

<Sealing section>
The seal portion 10 of the sealing device 1 of the present invention will be described.
The seal portion 10 includes a mounting portion 12 , a lip portion 14 , a connecting portion 16 , and a reinforcing ring 18 .

The mounting portion 12 is annular, extends in a direction parallel to the axis ω of the rotating shaft 100, and is attached to the inner surface 210 of the housing 200. The mounting portion 12 is sandwiched between the reinforcing ring 18 (described below) and the inner surface 210 of the housing 200, and is fixed so as to be in close contact with the inner surface 210 of the housing 200.

The lip portion 14 (14a, 14b) is in slidable contact with a fixing surface 22 of the sleeve tube portion 20, which will be described later.
However, the lip portion 14 (14a, 14b) may be in slidable contact with the outer surface 110 of the rotating shaft 100. In other words, it is sufficient that the lip portion 14 is in slidable contact with the outer surface 110 of the rotating shaft 100 and/or the fixing surface 22 of the sheath tube portion 20.
When the lip portion 14 slides on the fixing surface 22 of the sleeve tube portion 20, this is preferable because it is not necessary to plunge-machine the fixing surface 22.

1, the seal portion 10 has two lip portions (first lip portion 14a and second lip portion 14b). However, the sealing device of the present invention may have at least one lip portion.
In the preferred embodiment shown in FIG. 1, the first lip portion 14 a of the seal portion 10 has a garter spring 19 .

The connecting portion 16 connects the mounting portion 12 and the lip portion 14 .
In the case of the seal portion 10 of the preferred embodiment shown in Figure 1, the connecting portion 16 is connected to the mounting portion 12 at its end in a direction parallel to the axis ω of the rotating shaft 100. Then, it extends in a direction perpendicular to the axis ω of the rotating shaft 100 and is connected to the lip portion 14.
The connecting portion 16 is attached to a portion of the reinforcing ring 18 that extends in a direction perpendicular to the axis ω of the rotating shaft 100 .

The above-described mounting portion 12, lip portion 14, and connecting portion 16 are all made of elastic materials.
Examples of materials for the elastic body include synthetic rubbers such as nitrile rubber (NBR), hydrogenated nitrile rubber (H-NBR), acrylic rubber (ACM), and fluorocarbon rubber (FKM).

The reinforcing ring 18 is annular. As shown in Fig. 1, it is preferable that the cross section be substantially L-shaped and comprise a portion extending in a direction parallel to the axis ω of the rotating shaft 100 and a portion extending in a direction perpendicular to the axis ω.
The portion of the rotating shaft 100 extending in a direction parallel to the axis ω is preferably fixed to the inner surface 210 of the housing 200 via the mounting portion 12. In other words, the portion of the reinforcing rod 18 extending in a direction parallel to the axis ω of the rotating shaft 100 is in close contact with the inner surface of the mounting portion 12.
Furthermore, the portion of the reinforcing ring 18 that extends in a direction perpendicular to the axis ω of the rotating shaft 100 is in close contact with the connecting portion 16 .

The reinforcing ring 18 is preferably made of metal, more preferably stainless steel or cold rolled steel (SPCC).
The reinforcing ring 18 can be formed by pressing or forging.

The mounting portion 12, lip portion 14, connecting portion 16, and reinforcing ring 18 can be molded as a single unit. For example, the reinforcing ring 18 (and, if necessary, a garter spring 19) can be placed in a mold, an uncrosslinked rubber material can be charged, and the closed space in the mold can then be heated and pressurized to crosslink the rubber material, resulting in a seal portion 10 in which the mounting portion 12, lip portion 14, connecting portion 16, and reinforcing ring 18 are molded as a single unit.

This type of seal portion 10 serves to prevent foreign matter from entering from the outside and seal the internal lubricant.

<Sheath pipe part>
The sleeve pipe portion 20 of the sealing device 1 of the present invention will be described.
The sheath tube portion 20 is an annular portion that is fixed to the outer surface 110 of the rotating shaft 100 and has a fixed surface 22 that extends in a direction parallel to the axis ω of the rotating shaft 100, and a support surface 24 that is connected to the end of the fixed surface 22 and extends in a direction approaching the inner surface 210 of the housing 200.

Here, it is preferable that the fixing surface 22 and the support surface 24 are substantially perpendicular to each other in a cross section parallel to the axis ω of the rotating shaft 100 as shown in FIG.
In the preferred embodiment shown in Fig. 1, the fixing surface 22 and the support surface 24 are substantially perpendicular to each other in a cross section parallel to the axis ω of the rotating shaft 100. Therefore, the sheath tube portion 20 of the preferred embodiment shown in Fig. 1 has a substantially L-shaped cross section.
Here, "substantially perpendicular" does not necessarily mean that the angle does not have to be completely perpendicular. In other words, it is preferable that the fixing surface 22 and the support surface 24 form an angle of 90 degrees, but this angle may be 75 to 105 degrees (preferably 80 to 100 degrees, and more preferably 85 to 95 degrees).

The sheath tube portion 20 is preferably electrically conductive.
When the inner periphery of the ring in the conductive portion, which will be described later, does not contact the outer surface 110 of the rotating shaft 100, the sheath tube portion 20 is necessarily conductive.
On the other hand, when the inner periphery of the ring in the conductive portion, which will be described later, is in contact with the outer surface 110 of the rotating shaft 100, the sheath tube portion 20 does not necessarily have to be electrically conductive.

The sleeve tube portion 20 is preferably made of a metal, more preferably a metal having electrical conductivity, such as stainless steel, cold rolled steel (SPCC), brass, or aluminum.
The sheath tube portion 20 does not have to be made of metal, but may be made of resin, for example.

The sheath tube portion 20 can be formed by press working or forging.

<Conductive part>
The conductive portion 30 of the sealing device 1 of the present invention will be described.
The conductive portion 30 is ring-shaped, with its outer periphery 32 in contact with the inner surface 210 of the housing 200 and its main surface 34 fixed to the support surface 24 of the sleeve tube portion 20 .
When the rotating shaft 100 rotates, centrifugal force is applied to the conductive portion 30, and the ring outer periphery 32 of the conductive portion 30 is pressed against the inner surface 210 of the housing 200. As a result, the ring outer periphery 32 of the conductive portion 30 is stably brought into close contact with the inner surface 210 of the housing 200, ensuring electrical continuity between the rotating shaft 100 and the housing 200.

In the conductive portion 30 in the preferred example shown in FIG. 1, the inner ring circumference 36 of the conductive portion 30 is in contact with the outer surface 110 of the rotating shaft 100 .
In the sealing device 1 of the present invention, it is preferable that the ring inner circumference 36 of the conductive portion 30 contacts the outer surface 110 of the rotating shaft 100. This is because electrical conduction between the rotating shaft 100 and the housing 200 is facilitated. In this case, even if the above-mentioned sheath tube portion 20 does not have electrical conductivity, electrical conduction between the rotating shaft 100 and the housing 200 is achieved.

The method for fixing the main surface 34 of the conductive portion 30 to the support surface 24 of the sleeve tube portion 20 is not particularly limited; for example, they can be fixed using an adhesive. However, fixing them using metal bolts and nuts without using adhesive is preferable, as this makes it easier to ensure electrical continuity between the conductive portion 30 and sleeve tube portion 20, thereby improving electrical continuity between the rotating shaft 100 and housing 200.

The conductive portion 30 is preferably conductive and flexible.
The conductive portion 30 is preferably a cloth, more preferably a conductive woven fabric, and even more preferably a conductive nonwoven fabric.
Examples of materials for the conductive nonwoven fabric or conductive woven fabric include copper, silver, iron, and carbon.

2 is a schematic plan view of the conductive portion 30 before it is placed in the gap 205 between the outer surface 110 of the rotating shaft 100 and the inner surface 210 of the housing 200. As shown in FIG. 2, the conductive portion 30 preferably has a plurality of notches 38 on the outer periphery 32 of the ring.
This is because, when the conductive portion 30 has multiple notches 38 on the ring outer periphery 32, when the rotating shaft 100 rotates and centrifugal force is applied to the conductive portion 30, the ring outer periphery 32 of the conductive portion 30 can be more stably brought into close contact with the inner surface 210 of the housing 200, even if the conductive portion 30 is made of a material with poor elasticity such as a conductive nonwoven fabric. As a result, conductivity between the rotating shaft 100 and the housing 200 is more stably ensured.

In the preferred example shown in Figure 1, in the gap 205 between the outer surface 110 of the rotating shaft 100 and the inner surface 210 of the housing 200, the conductive portion 30, the sheath tube portion 20, and the seal portion 10 are arranged in this order from the outside to the inside.
In this case, the effect is achieved that the electrical continuity between the shaft and the housing can be maintained in a space-saving manner while maintaining the internal sealing properties.

REFERENCE SIGNS 1 sealing device of the present invention 10 seal portion 12 mounting portion 14 lip portion 14a first lip portion 14b second lip portion 16 connecting portion 18 reinforcing ring 19 garter spring 20 sleeve tube portion 22 fixing surface 24 support surface 30 conducting portion 32 outer periphery of ring 34 main surface 36 inner periphery of ring 38 notch 100 rotating shaft 110 outer surface of rotating shaft 200 housing 210 inner surface of housing ω axis of rotating shaft

Claims (6)

A sealing device that is disposed in a gap between an outer surface of a rotating shaft and an inner surface of a housing having a shaft hole into which the rotating shaft is inserted, and that seals the gap,
an annular sleeve tube portion fixed to the outer surface of the rotating shaft and including a fixing surface extending in an axial direction of the rotating shaft and a support surface connected to an end of the fixing surface and extending in a direction approaching an inner surface of the housing;
a ring-shaped conductive part, the outer periphery of which is in contact with the inner surface of the housing and the main surface of which is fixed to the support surface of the sleeve pipe part;
a seal portion including: an annular mounting portion made of an elastic body attached to the inner surface of the housing; a lip portion made of an elastic body that is in slidable contact with the outer surface of the rotating shaft and/or the fixed surface of the sleeve tube portion; a connecting portion made of an elastic body that connects the mounting portion and the lip portion; and a reinforcing ring that is in close contact with the inner surface of the mounting portion and also with the connecting portion, the seal portion preventing foreign matter from entering from the outside and sealing the lubricant inside;
and a sealing device which can electrically connect the rotating shaft and the housing. The sealing device described in claim 1, wherein the inner circumference of the ring in the conductive portion is in contact with the outer surface of the rotating shaft. The sealing device according to claim 1 or 2, wherein the conductive portion is made of conductive nonwoven fabric. A sealing device according to any one of claims 1 to 3, wherein the conductive portion, the sleeve tube portion, and the seal portion are arranged in this order in the gap between the outer surface of the rotating shaft and the inner surface of the housing, from the outer side to the inner side in the axial direction of the rotating shaft. A sealing device according to any one of claims 1 to 4, wherein the outer periphery of the ring in the conductive portion has multiple notches. A sealing device according to any one of claims 1 to 5, wherein the fixing surface and the support surface of the sleeve tube portion are substantially perpendicular to each other in a cross section parallel to the axis of the rotating shaft.