JP7496463B2 - Sealing device - Google Patents

Description

The present invention relates to a sealing device.

In automobiles and other vehicles, sealing devices with side lips are often used in the drivetrain and suspension, where resistance to dust and muddy water is required.

For example, Patent Document 1 discloses a sealing structure in which a side lip is also provided in a sealing device that seals by contacting a seal lip and a dust lip with the axle of a differential mechanism, and the side lip is brought into contact with a deflector provided on the output shaft. The side lip contacts the deflector on the outer side of the dust lip (see Figures 3 and 11), preventing dust and muddy water from entering the inside of the machine.

International Publication No. 2017/051920 JP 2014-196796 A

As shown in paragraph [0002] and Figure 10 of Patent Document 2, when storing or transporting finished or semi-finished sealing devices (oil seals), multiple sealing devices are stacked one on top of the other in the axial direction. However, in the case of sealing devices with side lips, the side lips protrude from the end faces, so stacking them requires some ingenuity.

The sealing device described in Patent Document 2 introduces a side lip into the space between the base reinforcing ring and the seal lip, preventing collisions between the sealing device structure and the side lip (see Figure 1 in Document 1).

However, in the structure described in Patent Document 2, the side lip cannot be made longer than the depth of the space in which it is housed when multiple sealing devices are stacked. This creates restrictions on the length of the side lip, and improvements are needed.

The objective of the present invention is to make it possible to stack multiple sealing devices regardless of the length dimension of the side lip.

One aspect of the sealing device of the present invention comprises an annular reinforcing ring with one end bent inward, a seal lip fixed to the bent portion of the reinforcing ring, extending toward the opposite side of the one end with a space between the inner circumferential side of the reinforcing ring and contacting a shaft passing through the reinforcing ring, a side lip fixed to the bent portion of the reinforcing ring and extending toward the opposite side of the seal lip within an axial region passing through the space, and a flat support surface provided at the bent portion of the reinforcing ring, positioned on the axial projection of the tip surface of the side lip, and the length from the base portion of the side lip is longer than the depth of the support surface on the seal lip side.

According to the present invention, multiple sealing devices can be stacked regardless of the length dimension of the side lip.

FIG. 2 is a horizontal cross-sectional view showing an embodiment of a sealing device attached to a differential case. FIG. 2 is a horizontal cross-sectional view showing one embodiment of a sealing device. FIG. 4 is an enlarged horizontal cross-sectional view showing the tip shape of the side lip. FIG. 2 is a vertical cross-sectional view illustrating a plurality of sealing devices stacked one on top of the other.

One embodiment of the sealing device will be described with reference to the drawings. The sealing device of this embodiment is used in the drive system or suspension of a vehicle such as an automobile, for example in a differential device.

In FIG. 1, reference numeral 11 denotes a differential case (hereinafter referred to as "diff case"). The diff case 11 has an axle 31 passing through an axle hole 12. The axle 31 is a shaft, and a dust cover 32 serving as a flange is fixed to the outer circumferential surface. The dust cover 32 is a circular member with a cup-shaped cross section, and is fixed by fitting onto the axle 31. The outside of the dust cover 32 is the outside of the machine O. In FIG. 1, the axle 31 and dust cover 32 are indicated by two-dot chain lines, and the axis A of the axle 31 is indicated by a dashed line.

The sealing device 101 is fitted and fixed in the shaft hole 12 of the differential case 11, with the axle 31 passing through it. Theoretically, the axis of the sealing device 101 coincides with the axis A of the axle 31. Therefore, in FIG. 1, the dashed line marked with the symbol A indicates the axis of the axle 31 and the sealing device 101.

As shown in Figures 1 and 2, the structural foundation of the sealing device 101 is the annular reinforcing ring 111. An elastic member 131 is fixed to the reinforcing ring 111, and a fitting portion 132, a seal lip 133, a dust lip 134, and a side lip 151, which will be described later, are integrally formed. The seal lip 133 and the dust lip 134 are in contact with the axle 31. The side lip 151 has its tip inserted into the dust cover 32, forming a labyrinth seal that maintains a non-contact state with the inner surface of the dust cover 32. The inside of the seal lip 133 is the interior I.

In another embodiment, the side lip 151 may be in a form constituting a contact type seal, as well as a form constituting a labyrinth seal that is in a non-contact state with the dust cover 32. For example, the side lip 151 may be in a form in which the tip portion contacts a flange provided on the axle 31.

The reinforcing ring 111 is a metal annular member. This annular member has a cylindrical portion 112 with a diameter slightly smaller than the shaft hole 12, and a bent portion 113 formed by bending one end of the cylindrical portion 112 inward. The bent portion 113 has a step shape in the direction in which the side lip 151 extends. More specifically, the bent portion 113 is bent at a right angle at one end of the cylindrical portion 112, the central portion extends obliquely in the direction in which the side lip 151 extends, and the tip portion is bent at a right angle again. For ease of explanation, the portion that gives this shape to the bent portion 113 is called the step portion 113a.

The elastic member 131 is a rubber-like elastic member made of various types of rubber, and is fixed to the reinforcing ring 111 by, for example, vulcanization adhesion. The fixing portion of the elastic member 131 on the reinforcing ring 111 is the entire cylindrical portion 112 and the bent portion 113, excluding the portion that is required to support the reinforcing ring 111 during the vulcanization adhesion. The elastic member 131 is molded continuously and integrally so as to cover the entire cylindrical portion 112 and the bent portion 113.

The fitting portion 132 is integrally formed with an elastic member 131 fixed to the outer circumferential surface of the cylindrical portion 112. The outer diameter of the fitting portion 132 is larger than the inner diameter of the axial hole 12 of the differential case 11, and the difference is the fitting allowance of the fitting portion 132 with respect to the axial hole 12. When the fitting portion 132 is fitted into the axial hole 12, the sealing device 101 is prevented from coming off in the axial direction by a non-removal structure (not shown).

The seal lip 133 and dust lip 134 are integrally molded by an elastic member 131 fixed to cover the inner peripheral edge area of the bent portion 113. The seal lip 133 has an annular shape extending obliquely toward the inside of the machine I, and the dust lip 134 has an annular shape extending obliquely toward the outside of the machine O. Both the seal lip 133 and the dust lip 134 have their respective lip ends 133a, 134a in contact with the axle 31.

The seal lip 133 has an annular groove 135 on the outer peripheral surface behind the lip end 133a, and a garter spring 136 is attached to the groove 135. The garter spring 136 strengthens the contact force of the seal lip 133 against the axle 31.

The side lip 151 is integrally formed with the elastic member 131 fixed to cover the outer surface and inner peripheral edge of the bent portion 113, and has a ring shape extending toward the dust cover 32. When viewed from the radial side, the side lip 151 has two regions.

The first is the region on the base end side. For ease of explanation, this region is referred to as base 151A. Base 151A has a shape that increases in diameter from the base of side lip 151 toward the tip.

The second is the region that extends from the base 151A toward the tip. For ease of explanation, this region is referred to as the tip 151B. The tip 151B has a straight shape with no change in diameter. Therefore, the tip 151B extends parallel to the axis A.

As shown in FIG. 3, a protrusion 153 is provided on the tip surface 152 of the side lip 151. The protrusion 153 has an annular shape and is located in the center between the inner and outer circumferential sides of the annular tip surface 152.

In the present embodiment, the side lip 151 is structured to form a labyrinth seal between itself and the dust cover 32, so the tip surface 152 of the tip 151B is formed in a shape that does not assume contact with the dust cover 32. In contrast, as described above, in the case of a contact-type seal structure that contacts a flange or the like provided on the axle 31, the tip surface 152 of the tip 151B of the side lip 151 is given a shape suitable for contacting the flange. For example, it is a shape that has a flat planar shape in a direction perpendicular to the axis A.

As shown in FIG. 2, the sealing device 101 has a space S with a concave cross section between the cylindrical portion 112 of the reinforcing ring 111 and the seal lip 133. The space S is used as an area to store the side lip 151 when multiple sealing devices 101 are stacked and stored (see FIG. 4).

The sealing device 101 forms an annular support surface 137 inside the space S. The support surface 137 is a flat, planar surface on one surface of the bent portion 113 on the seal lip 133 side, perpendicular to the axis A provided on the surface of the elastic member 131. Such a planar support surface 137 is provided on a projection surface on the axial direction of the tip surface 152 of the side lip 151. In FIG. 2, an example of the "axis" on which the projection surface is located is illustrated by the two-dot chain line indicated by the symbol B.

As shown in FIG. 2, the sealing device 101 is set such that the length L2 from the base of the side lip 151 is longer than the placement depth L1 of the support surface 137 on the seal lip 133 side. More specifically, the placement depth L1 of the support surface 137 is determined by the length dimension from the end face E1 on the inboard I side of the sealing device 101 to the support surface 137. The length L2 of the side lip 151 is determined by the length dimension from the outer surface E2 of the elastic member 131 fixed to the outer surface side of the bent portion 113 of the reinforcing ring 111 to the tip surface 152 (protrusion 153) of the side lip 151.

In this configuration, the sealing device 101, which prevents oil leakage from the interior I with a seal lip 133 in contact with the axle 31, prevents dust and muddy water from entering the interior I with a double seal structure consisting of a dust lip 134 in contact with the axle 31 and a side lip 151 in contact with the dust cover 32. This double seal structure provides high dust resistance and muddy water resistance.

As shown in FIG. 4, when a finished or semi-finished sealing device 101 is stored or transported, a plurality of sealing devices 101 are stacked one on top of the other in the axial direction. At this time, the sealing device 101 has a support surface 137 on the axial projection surface of the tip surface 152 of the side lip 151, so that the tip surface 152 of the side lip 151 of the sealing device 101 located above is placed on the support surface 137 of the sealing device 101 located below. In the sealing device 101 of this embodiment, the rigidity of the side lip 151 is high when a plurality of sealing devices 101 are stacked, making it possible to stack the sealing devices 101 in this manner.

The reason why the side lip 151 has high rigidity when a plurality of sealing devices 101 are stacked is due to the following configuration of the sealing device 101.
・Side lip landing condition ・Side lip shape ・Shape of the bent part of the reinforcing ring

(1) Landing State of Side Lip The tip surface 152 of the side lip 151 is in surface contact with the support surface 137. For this reason, the side lip 151 of the upper sealing device 101 that has landed on the support surface 137 of the lower sealing device 101 is unlikely to generate a moment that rotates left and right around the tip surface 152.

As a comparative example, consider a case where the tip surface of the side lip is inclined with respect to a virtual plane perpendicular to the axis A (see, for example, the side lip in Patent Document 1). In this case, when the side lip lands on a flat surface such as the support surface 137, the edge of the tip of the side lip first comes into contact with the flat surface, and then the entire tip surface tries to make contact with the flat surface. This is because a moment is generated about the edge of the tip when the edge of the tip comes into contact with the flat surface. This moment causes the side lip to rotate about the edge and begin to bend. For this reason, there is a concern that the side lip may deform if the sealing devices of the comparative example are stacked one on top of the other.

The side lip 151 of this embodiment is unlikely to generate a moment that rotates left and right around the tip surface 152, even if the sealing devices 101 are stacked vertically. This makes the side lip 151 highly rigid, making it possible to stack the sealing devices 101 vertically.

(2) Shape of the Side Lip The tip 151B of the side lip 151 has a straight shape parallel to the axis A. Therefore, when the sealing devices 101 are stacked vertically, the balance of forces between the inner peripheral side and the outer peripheral side of the side lip 151 becomes more even. Therefore, the rigidity of the side lip 151 is high, and it becomes possible to stack the sealing devices 101 vertically.

(3) Shape of the bent portion of the reinforcing ring The bent portion 113 of the reinforcing ring 111 has a step portion 113a. The ratio of the elastic member 131 to the axial length of the side lip 151 is accordingly reduced, and high rigidity is obtained by the stronger metal reinforcing ring 111. This makes it possible to stack the sealing devices 101 vertically.

If the sealing devices 101 are left stacked one on top of the other for a long period of time, a phenomenon called adhesion may occur between the support surface 137 and the side lip 151, both of which are made of rubber-like elastic materials. In this embodiment, the side lip 151 has a protrusion 153 on the tip surface 152 to reduce the contact area with the support surface 137, or to reduce the contact pressure of the tip surface 152 with the support surface 137. This makes it difficult for adhesion to occur between the support surface 137 and the side lip 151.

Various modifications and alterations are permitted when implementing the present invention. For example, in the present embodiment, an example is shown in which the support surface 137 is provided on the surface of the elastic member 131, but this is not essential. The support surface 137 may be provided on the metal surface of the bent portion 113 of the reinforcing ring 111. As mentioned above, the side lip 151 may not only be a non-contact type labyrinth seal, but also a contact type seal that contacts, for example, a flange provided on the axle 31. All other modifications and alterations are possible.

REFERENCE SIGNS LIST 11 differential case 12 shaft hole 31 axle 32 dust cover 101 sealing device 111 reinforcing ring 112 cylindrical portion 113 bent portion 113a step portion 131 elastic member 132 fitting portion 133 seal lip 133a lip end 134 dust lip 134a lip end 135 groove 136 garter spring 137 support surface 151 side lip 151A base portion 151B tip portion 152 tip surface 153 projection A shaft center B shaft E1 end surface on the inside of the sealing device E2 outer surface of the elastic member I inside the machine O outside the machine S space

Claims (11)

A reinforcing ring is provided around the shaft center;
an elastic member attached to the reinforcing ring and formed of an annular elastic body around the axis,
The elastic member is
a seal lip extending toward one side in the axial direction;
a side lip extending toward the other side opposite to the one side in the axial direction and having an annular tip surface around the axis facing the other side;
a support surface annular about the axis facing the one side,
A sealing device, wherein the support surface supports the tip surface of another sealing device. The sealing device according to claim 1, wherein the elastic member has an annular protrusion around the axis that protrudes from the tip surface toward the other side. The sealing device according to claim 1 or 2, wherein the support surface and the tip surface of the other sealing device are in at least partial surface contact. The support surface is along a plane perpendicular to the axis,
The sealing device according to any one of claims 1 to 3, wherein the tip surface is along a plane perpendicular to the axis. The sealing device according to any one of claims 1 to 4, wherein the support surface at least partially overlaps the tip surface in the axial direction. The sealing device according to any one of claims 1 to 5, wherein the side lip has a base portion whose diameter relative to the axis increases from the base end of the one side toward the tip end of the other side, and a tip portion provided on the other side of the base portion whose diameter relative to the axis is constant from the base end of the one side toward the tip end of the other side. The sealing device according to any one of claims 1 to 6, wherein the depth from a plane including the end of the sealing device on one side to the support surface defined along the axial direction is smaller than the length of the side lip from the base end of the one side to the tip of the other side along the axial direction. The sealing device according to any one of claims 1 to 7, wherein the reinforcing ring has an annular cylindrical portion around the axis and an annular bent portion bent inward from the other side of the cylindrical portion toward the axis. The sealing device according to claim 8, wherein the bent portion has an oblique portion whose diameter relative to the axis decreases from the one side to the other side. The sealing device according to claim 8 or 9, wherein the support surface is provided on the one side of the bent portion. The sealing device according to any one of claims 8 to 10, wherein the support surface is provided in a space between the seal lip and the cylindrical portion.

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