JP2008025628A - Sealing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealing device having reduced rotating torque while securing the performance of sealing mud water particularly during high speed rotation. <P>SOLUTION: The sealing device comprises a seal body 2 fitted to an inside member 12 as a rotating side member and having a main lip 7 and a side lip 8, and a side plate part 3 consisting of a large diameter cylindrical portion 10a fitted to an outside member 13 as a fixed side member, an annular plate portion 10b, and a small diameter cylindrical portion 10c. The main lip 7 is set to be slidably put in close contact with the small diameter cylindrical portion 10c with a contact load thereon during stop or low speed rotation, and to be opened radially outward with centrifugal force to reduce the contact load on the small diameter cylindrical portion 10c during high speed rotation. The side lip 8 which is provided radially outside of the main lip 7 is set to be slidably put in close contact with the annular plate portion 10b with interference during stop or low/high speed rotation. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a sealing device for sealing an annular space between an inner member and an outer member that rotate relative to each other.

Conventionally, as a sealing device mounted in an annular space formed between an inner member and an outer member that rotate relative to each other, a metal cored bar with a sealing member made of an elastic body is known. Yes. This sealing device has a structure in which a metal core is fitted to an outer member which is a fixed member, and a seal lip formed on the inner periphery of the seal member is always in sliding contact with an inner member which is a rotating member. There was a problem with the durability of the seal lip. For this reason, a reduction in torque of the seal lip has been demanded.
In order to solve this problem, a sealing device as shown in FIG. 2 has been proposed (see Patent Document 1). This sealing device 21 has a seal body 22 attached to a rotating shaft 28 as a rotating body as an inner member, and a fixing member ring (side plate) 23 attached to a casing 29 as a stationary part as an outer member. is doing. The seal body 22 is a seal having a reinforcing ring (core metal) 24 fitted to the rotary shaft 28 and a seal lip 26 fixed to the reinforcing ring 24 and slidably contacted with the fixing member ring 23. A member 25 and a garter spring (spring ring) 27 disposed on the outer peripheral side of the seal lip 26 are provided. The seal lip 26 and the garter spring 27 are opened at different rotational speeds by centrifugal force. Is formed.

JP 2005-257051 A

According to the sealing device 21 described in Patent Document 1, when the rotary shaft 28 rotates at high speed, the friction torque of the seal lip 26 is reduced by separating the tip of the seal lip 26 from the fixing member ring 23. In addition, when the rotary shaft 28 is stopped and when rotating at a low speed, the tip of the seal lip 26 is elastically brought into contact with the fixing member ring 23 by the garter spring 27, so Lubricant leakage can be prevented. However, in this sealing device 21, foreign matter such as muddy water may enter the bearing inside A from the gap between the fixing member ring 23 and the seal member 25 when the rotary shaft 28 rotates at high speed.
This invention is made in view of such a situation, and it aims at providing the sealing device which can reduce the rotational torque while ensuring the sealing performance with respect to muddy water, especially the sealing performance at the time of high speed rotation. Yes.

The sealing device of the present invention is a sealing device mounted in an annular space configured between an inner member that is a rotation side member that rotates relative to each other and an outer member that is a stationary side member,
A seal body fitted to the inner member and having a main lip and a side lip;
A side plate portion comprising a large diameter cylindrical portion fitted to the outer member, an annular plate portion extending radially inward from the large diameter cylindrical portion, and a small diameter cylindrical portion extending in the axial direction from the annular plate portion. And
When the main lip is stopped or rotated at a low speed, the main lip is in close contact with the small-diameter cylindrical portion so as to be slidable, and at a high-speed rotation, the main lip is opened outward in the radial direction by centrifugal force and the contact load with the small-diameter cylindrical portion is The side lip is provided on the outer side in the radial direction from the main lip, and the annular plate portion is slidable at the time of stop or low speed rotation and high speed rotation. It is characterized by being set closely to

  Thus, according to the sealing device of the present invention, when the main lip and the side lip are stopped or rotated at a low speed, the main lip and the side lip are set so as to be slidably in close contact with the side plate portion. Sealing performance during low-speed rotation is ensured. The main lip and the side lip are fixed to the inner member, which is the rotating member, not the outer member, which is the stationary member, and rotate together with the inner member. Torque can be reduced by opening in the direction and reducing the contact load with the side plate portion. Furthermore, since the side lip located radially outside the main lip is set so as to be slidably in close contact with the side plate portion even at high speed rotation, sealing performance against muddy water at high speed rotation is ensured.

In the sealing device, it is preferable that a spring ring is attached to the main lip, and the contact load is applied by a tightening force of the spring ring.
In this case, since the spring ring is affected by the centrifugal force before the main lip during rotation, the tightening force can be changed responsively to the rotation, so that the contact between the main lip and the side plate during high-speed rotation can be achieved. The load can be reduced responsively. Further, when stopped or rotated at a low speed, the main lip can be brought into sliding contact with the side plate portion by the tightening force of the spring ring to effectively prevent muddy water from entering from the outside.

In the sealing device, the seal body is formed by fixing a seal member made of an elastic member to a metal core, and the core and the seal member are fitted to the inner member, It is preferable that the side plate portion has an elastic member fixed to a metal side plate, and the side plate and the elastic member are fitted to the outer member.
In this case, by fitting the elastic member together with the metal (core metal and side plate), the difference in thermal expansion between the core metal and the inner member and between the side plate and the outer member is absorbed. And the side plate can be prevented from coming off.

  ADVANTAGE OF THE INVENTION According to this invention, while ensuring the sealing performance with respect to muddy water, especially the sealing performance at the time of high speed rotation, the sealing device which can reduce rotational torque can be obtained.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
FIG. 1 is a schematic cross-sectional view showing a sealing device according to one embodiment of the present invention. This sealing device 1 is used, for example, in a rolling bearing device to which a wheel of an automobile is attached, and is mounted in an annular space between an inner member 12 and an outer member 13 that are arranged concentrically and relatively rotatably. Thus, the lubricant inside the bearing A is prevented from leaking to the outer side B, and foreign matter such as muddy water is prevented from entering the bearing inside A from the outer side B. The sealing device 1 shown in FIG. 1 shows a free state before deformation, which is before being mounted between the inner member 12 and the outer member 13.

The sealing device 1 includes a seal body 2 fitted to an inner member 12 as a rotation side member, and a side plate portion 3 fitted to an outer member 13 as a fixed side member.
The seal body 2 includes an annular cored bar 4 having a substantially inverted L-shaped cross section, a seal member 5 fixed to the cored bar 4, and a spring ring 6.

The metal core 4 of the seal body 2 is an annular member made of metal (for example, SPCC), and the cylindrical portion 4a fixed to the inner member 12, and the outer side B end of the cylindrical portion 4a radially outward. And an annular plate portion 4b that is bent.
The seal member 5 is made of an elastic member such as synthetic rubber (for example, acrylonitrile-butadiene rubber (NBR), acrylic rubber (ACM)), and is fixed to the core metal 4 by adhesion or baking by vulcanization. The seal member 5 covers the outer side B of the annular plate portion 4b of the core metal 4 and is fitted to the inner member 12; the outer peripheral portion 5b covering the outer peripheral side of the annular plate portion 4b; A main body portion 5c covering the vicinity of the middle of the bearing portion A side of the plate portion 4b, and a substantially triangular section extending from the inner peripheral side of the main body portion 5c to the inner member 12 side and the bearing inner portion A side. A main lip 7 having a shape, and a side lip 8 extending in a skirt shape from the middle part of the main body part 5c, which is radially outward from the main lip 7, radially outwardly on the bearing inner side A are provided. A circumferential groove 9 is formed on the outer peripheral surface of the main lip 7, and a spring ring 6 called a garter spring is attached to the circumferential groove 9. The spring ring 6 fastens the main lip 7 inward in the radial direction.

The side plate portion 3 includes an annular side plate 10 having a substantially U-shaped cross section, and an elastic fitting portion 11 that is fixed to the side plate 10 and fitted to the outer member 13.
The side plate 10 is an annular member made of metal (for example, SPCC), and has a large-diameter cylindrical portion 10a fitted to the outer member 13, and a radially inner portion from an end portion on the bearing inside A side of the large-diameter cylindrical portion 10a. An annular plate portion 10b bent in the direction and a small-diameter cylindrical portion 10c bent from the inner peripheral end portion of the annular plate portion 10b to the outer side B are configured.
The elastic fitting portion 11 is made of an elastic member such as synthetic rubber (for example, acrylonitrile-butadiene rubber (NBR), acrylic rubber (ACM)), and the bearing inner side A of the annular plate portion 10b by adhesion or baking by vulcanization. The outer peripheral surface 11 a is fitted to the outer member 13.
Here, the metal core 4 and the fitting portion 5a of the seal member 5 are fitted to the inner member 12, and the large-diameter cylindrical portion 10a of the side plate 10 and the outer peripheral surface 11a of the elastic fitting portion 11 are outer members. 13 is fitted. By fitting the elastic members 5 and 11 together with the metal (the core metal 4 and the side plate 10), the difference in thermal expansion between the core metal 4 and the inner member 12 and between the side plate 10 and the outer member 13 is absorbed. Thus, the cored bar 4 and the side plate 10 are prevented from coming off.

  The main lip 7 is slidably in close contact with the small-diameter cylindrical portion 10c when stopped or rotated at low speed, and the contact load with the small-diameter cylindrical portion 10c is reduced by centrifugal force during high-speed rotation. Is set to Here, a spring ring 6 is attached to the main lip 7, and the contact load is applied by a tightening force of the spring ring 6. That is, the main lip 7 is designed so that the contact load with the small-diameter cylindrical portion 10c of the side plate 10 is zero when the spring ring 6 is not attached. When the main lip 7 is assembled to the side plate portion 3, the main lip 7 The tip of 7 and the surface of the small diameter cylindrical portion 10c form a zero gap. When the spring ring 6 is attached to the circumferential groove 9 of the main lip 7, a contact load is applied only by the tightening force of the spring ring 6, and the tip of the main lip 7 comes into sliding contact with the surface of the small diameter cylindrical portion 10c. The lubricant inside the bearing A is prevented from leaking to the outer side B during stoppage and low-speed rotation. Further, since the main lip 7 is fixed to the inner member 12 which is a rotation side member and rotates together with the inner member 12, the main lip 7 opens radially outward by centrifugal force during high speed rotation and contacts the small diameter cylindrical portion 10c. The torque is reduced by reducing the load.

Further, the side lip 8 is provided on the outer side in the radial direction from the main lip 7 and is set so as to be slidably in close contact with the annular plate portion 10b at the time of stop or low speed rotation and high speed rotation. . That is, when the side lip 8 is assembled to the side plate portion 3, the tip of the side lip 8 faces the outer peripheral side and is tightly slidably close to the annular plate portion 10b of the side plate 10, This prevents foreign matter such as muddy water from entering the bearing inside A from the outside B during stoppage or low-speed rotation. Since the side lip 8 is slidably in close contact with the annular plate portion 10b even during high speed rotation, the sealing performance against muddy water during high speed rotation is ensured.
Further, by forming a small gap between the large-diameter cylindrical portion 10a of the side plate 10 and the outer peripheral portion 5b of the seal member 5, between the large-diameter cylindrical portion 10a of the side plate 10 and the outer peripheral portion 5b of the seal member 5. A labyrinth seal S is formed. The labyrinth seal S makes it difficult for muddy water to approach from the outside B, and the amount of muddy water that enters the sealing device 1 is reduced.

In the sealing device 1 configured in this way, as described above, the main lip 7 and the side lip 8 are set so as to be slidably in close contact with the side plate portion 3 when stopped or rotated at a low speed. By this, the sealing performance at the time of stop or low-speed rotation is ensured. The main lip 7 and the side lip 8 are fixed not to the fixed side member (outer member) 13 but to the rotary side member (inner member) 12 and rotate together with the inner member 12. Torque can be reduced by opening outward in the radial direction by centrifugal force and reducing the contact load with the small-diameter cylindrical portion 10c. Further, the side lip 8 located radially outward from the main lip 7 is set so as to be slidably in close contact with the annular plate portion 10b even during high-speed rotation, thereby ensuring sealing against muddy water during high-speed rotation. Has been.
Here, the spring ring 6 is attached to the main lip 7 and a contact load is applied by the tightening force of the spring ring 6, so that the tightening force can be responsively changed with respect to rotation. The contact load between the main lip 7 and the small diameter cylindrical portion 10c can be reduced with good reactivity. Further, when stopping or rotating at a low speed, the main lip 7 can be brought into sliding contact with the small-diameter cylindrical portion 10c by the tightening force of the spring ring 6 to effectively prevent muddy water from entering from the outside B.

  In the above embodiment, the spring ring 6 is attached to the main lip 7, but the spring ring 6 may not necessarily be attached. In this case, the main lip 7 may be assembled to the small diameter cylindrical portion 10c so that the tip of the main lip 7 has a contact load with the small diameter cylindrical portion 10c.

It is sectional drawing which shows the sealing device which concerns on one embodiment of this invention. It is sectional drawing which shows the conventional sealing device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sealing device 2 Seal main body 3 Side plate part 4 Core metal 5 Seal member 6 Spring ring 7 Main lip 8 Side lip 10 Side plate 10a Large diameter cylindrical part 10b Annular plate part 10c Small diameter cylindrical part 11 Elastic fitting part 12 Inner member 13 Outer member

Claims (3)

A sealing device that is mounted in an annular space configured between an inner member that is a rotating member that rotates relative to each other and an outer member that is a stationary member,
A seal body fitted to the inner member and having a main lip and a side lip;
A side plate portion comprising a large diameter cylindrical portion fitted to the outer member, an annular plate portion extending radially inward from the large diameter cylindrical portion, and a small diameter cylindrical portion extending in the axial direction from the annular plate portion. And
When the main lip is stopped or rotated at a low speed, the main lip is in close contact with the small-diameter cylindrical portion so as to be slidable, and at a high-speed rotation, the main lip is opened outward in the radial direction by centrifugal force and the contact load with the small-diameter cylindrical portion is The side lip is provided on the outer side in the radial direction from the main lip, and the annular plate portion is slidable at the time of stop or low speed rotation and high speed rotation. A sealing device characterized in that it is set so as to be in close contact with.   The sealing device according to claim 1, wherein a spring ring is attached to the main lip, and the contact load is applied by a tightening force of the spring ring.   The seal body is formed by fixing a seal member made of an elastic member to a metal core, the core and the seal member are fitted to the inner member, and the side plate portion is made of metal. The sealing device according to claim 1, wherein an elastic member is fixed to a side plate made of metal, and the side plate and the elastic member are fitted to the outer member.

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