JP2010265968A - Dynamic seal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dynamic seal in which rotation torque and a wearing amount of a seal lip do not increase not to make a heat generation amount larger, even if an outer member rotates in high speed, in the dynamic seal having a structure in which the seal lip contacts an inner member. <P>SOLUTION: The dynamic seal 11 is mounted to the outer member OP which is positioned/rotated on the radial outside of an outer peripheral surface of the inner member IP to seal a circular opening therebetween. A constriction 16 is formed between an inner peripheral surface 12A of a core metal 12 and the seal lip 14. The seal lip 14 is made to have a shape in which axial partial output of centrifugal force acts on the outside. The seal lip 14 is pressure-welded to the inner member IP in a state of mounting the dynamic seal 11 to the outer member OP. When the rotation speed of the outer member OP exceeds a predetermined value, the seal lip 14 is separated from the inner member IP by the centrifugal force. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention is attached to an outer member that rotates and is positioned radially outward from the outer peripheral surface of the inner member, and covers an annular opening between the inner member and the outer member, covering the annular cored bar with an elastic body. The present invention relates to an exercise seal having a structure in which an inner peripheral side end portion of the elastic body is a seal lip and the seal lip contacts an inner member.

  For example, an auxiliary machine around an engine such as an automobile alternator and an air conditioner is driven by a timing belt connected to an engine crank. used. These rolling bearings for pulleys are water and dust resistant, which can prevent foreign matter such as muddy water or dust from entering between the outer ring and the inner ring of the bearing in consideration of rain or bad roads. Is required.

The rolling bearing has an elastic body such as a synthetic rubber or the like in an annular metal core so as to have the water resistance and dust resistance and prevent leakage of a lubricant such as grease enclosed inside. A bearing seal, which is a motion seal with the inner peripheral side end of the elastic body as a seal lip, is attached to the outer ring so as to close the annular opening between the outer ring and the inner ring. A combination of a non-contact type and a contact type with a dust lip that is a non-contact lip on the outer side in the inner ring side and a contact lip on the inner side in the axial direction on the inner peripheral side. And the dust resistance are improved (for example, refer to Patent Document 1).
In such a movement seal, a constricted portion is formed in the elastic body between the inner peripheral surface of the core metal and the seal lip in order to suppress an increase in rotational torque, and the centrifugal force generated by the outer ring rotation is also reduced. The shape is determined so as to balance, that is, to reduce the displacement of the seal lip as much as possible by reducing the axial component of centrifugal force generated in the seal lip (see, for example, Patent Document 1).
(For example, refer to Patent Document 1).

JP 2003-4055 A

Since the conventional seal lip structure in which the seal lip is in contact with the inner member as in Patent Document 1 has a constricted portion formed on the elastic body, the seal is rigid in a state where the seal lip (contact lip) is pressed against the inner ring. Since the constricted portion having a small diameter is mainly deformed, the rotational torque can be made relatively small.
However, since the axial force component of centrifugal force is designed to be small even if the rotational speed of the outer ring (outer member) fluctuates, the seal lip does not depend on the rotational speed of the outer ring and the inner ring (inner member). Therefore, when the outer ring rotates at a high speed, the rotational torque increases, the wear amount of the seal lip increases, and the heat generation amount increases.

  Therefore, in view of the above-mentioned situation, the present invention intends to solve the problem that the seal seal lip is in contact with the inner member, and the rotational torque and the wear of the seal lip are worn even when the outer member speed is increased. The object is to provide an exercise seal that does not increase in quantity and does not increase in calorific value.

  In order to solve the above problems, the exercise seal according to the present invention is attached to an outer member that is positioned radially outward from the outer peripheral surface of the inner member, and closes an annular opening between the inner member and the outer member. An exercise seal in which an annular core is covered with an elastic body and an inner peripheral end of the elastic body is used as a seal lip, and a constricted portion between the inner peripheral surface of the core and the seal lip The seal lip is shaped so that the axial component of centrifugal force acts on the outside, and the seal lip is pressed against the inner member in a state where the seal for movement is attached to the outer member, When the rotational speed of the outer member exceeds a predetermined value, the seal lip is separated from the inner member by centrifugal force.

  Here, it is preferable that the elastic body is formed with a stop portion that stops the seal lip when the seal lip is separated from the inner member.

  In addition, it is preferable that a circumferential groove or a step is formed in the inner member so that a labyrinth sealing effect is obtained when the seal lip is separated from the inner member.

  According to the exercise seal of the present invention, the annular core bar is attached to the outer member that is positioned radially outside the outer peripheral surface of the inner member and rotates, and closes the annular opening between the inner member and the outer member. And an elastic seal that covers the elastic body and uses the inner peripheral side end of the elastic body as a seal lip, forming a constricted portion between the inner peripheral surface of the cored bar and the seal lip, The seal lip is shaped so that the axial component of centrifugal force acts on the outside, and the seal lip is pressed against the inner member in a state where the seal for movement is attached to the outer member, and the rotational speed of the outer member If the seal lip exceeds the predetermined value, the seal lip is separated from the inner member by centrifugal force. Therefore, when the rotational speed of the outer member exceeds the predetermined value and the seal lip is separated from the inner member by centrifugal force, the contact seal In this state, since the resistance and wear of the seal lip due to the sliding of the seal lip to the inner member are eliminated, the rotation of the outer member in the motion seal having a structure in which the conventional seal lip contacts the inner member is eliminated. When the speed is increased, the problem that the rotational torque and the amount of wear of the seal lip increase and the amount of heat generation increases can be solved.

  In addition, when the rotation speed of the outer member does not exceed a predetermined value, for example, when the rotation speed is relatively low, the outer member can reliably function and seal as a contact seal, and the rotation speed of the outer member is predetermined. When the seal lip is separated from the inner member beyond the value, for example, when the rotational speed is relatively high, the contact lip is lost, but the seal lip functions as a non-contact seal even when the seal lip is separated from the inner member. Is rotating at a relatively high speed, it is possible to suppress entry of foreign matter between the inner member and the outer member and leakage of the lubricant from between the inner member and the outer member.

  In addition to the above-described effects, the rotational speed of the outer member may exceed a predetermined value if the elastic body has a stopper for stopping the seal lip when the seal lip is separated from the inner member. In a state where the seal lip is separated from the inner member, flapping of the seal lip can be suppressed to prevent the lip from being broken, and the function as a non-contact seal can be stabilized.

  Further, when a circumferential groove or a step is formed in the inner member so that a labyrinth sealing effect is obtained when the seal lip is separated from the inner member, the seal lip separated from the inner member by centrifugal force The labyrinth effect of the non-contact seal by the circumferential groove or the step portion can improve the sealing performance when the seal lip is separated from the inner member by centrifugal force.

1 is a cross-sectional view of a rolling bearing equipped with an axial contact type exercise seal according to an embodiment of the present invention. It is sectional drawing which expands and shows the principal part similarly, (a) has shown the low speed rotation state, (b) has shown the high speed rotation state. 1 is a cross-sectional view of a rolling bearing equipped with a radial contact type motion seal according to an embodiment of the present invention. It is sectional drawing which expands and shows the principal part similarly, (a) has shown the low speed rotation state, (b) has shown the high speed rotation state. 1 is a cross-sectional view of a one-way clutch equipped with a radial contact type exercise seal according to an embodiment of the present invention. Similarly, it is sectional drawing which expands and shows the principal part, The high-speed rotation state is shown.

  Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments shown in the accompanying drawings, and includes all the embodiments that satisfy the requirements described in the claims. It is a waste. In the following, the axial direction of the rotating shaft is referred to as “axial direction”, and the rotational radial direction is referred to as “radial direction”. In addition, in the cross-sectional views of FIGS. 1 to 6, in consideration of the visibility of these drawings, a part of the outline line that is visible on the side opposite to the cut end face is omitted, and a part is shown as a cut end face view.

1 and 2 show a rolling bearing 1 equipped with an axial contact type motion seal 11, which is held by an inner ring 2 as an inner member IP and an outer ring 3 as an outer member OP. .. Are relatively rotated via the rolling elements 5 held by the vessel 4, and grease 10 is sealed between the inner ring 2 and the outer ring 3 as a lubricant, and the bearing width of the rolling elements 5,. On the left and right sides of the direction, there are mounted exercise seals 11 and 11 having a substantially annular shape in front view, which close the annular openings A and A between the inner ring 2 and the outer ring 3.
The seal 11 may be a single shield type that seals only one side of the rolling bearing 1 depending on the place of use, instead of the double shield type that seals both sides of the rolling bearing 1 as shown in FIG. That is, the seal 11 is attached to at least one of the left and right annular openings A and A between the inner ring 2 and the outer ring 3 of the rolling bearing 1 in the bearing width direction.

As shown in FIG. 2A, the seal 11 covers the elastic body 13 such as synthetic rubber by vulcanization adhesion continuously to the outer peripheral portion and the inner peripheral portion of the annular metal core 12 made of a steel plate or the like. The inner peripheral side end of the elastic body 13 is a seal lip 14, and the outer peripheral end is an outer diameter mounting portion 15, and the side wall surface 8 extending in the radial direction of the inner ring 2 is axially inner of the seal lip 14. When the contact lip (main lip) is pressed, leakage of the grease 10 filled in the bearing 1 can be prevented, and entry of foreign matter from the outside can be prevented, and the shaft of the seal lip 14 can be prevented. Since the non-contact lip (dust strip) on the outer side in the direction is opposed to the outer peripheral surface of the inner ring 2 on the outer side of the inner ring peripheral groove 6, which is also called a seal groove formed on the outer peripheral surface of the inner ring 2, with a minute gap therebetween, By labyrinth seal effect The intrusion of foreign matter from the parts can be reduced.
Further, by fitting the outer diameter mounting portion 15 into the outer ring circumferential groove 7 formed on the inner circumferential surface of the outer ring 3, the seal 11 is positioned and fixed with respect to the bearing 1, and from the outer diameter portion of the seal 11. Intrusion of foreign matter can be prevented.

Here, as the rubber material used as the elastic body 13, as a rubber material having good oil resistance, nitrile rubber (NBR), hydrogenated nitrile rubber (HNBR), acrylic rubber (ACM), ethylene / acrylic rubber (AEM) One or two or more kinds of rubbers such as fluorine rubber (FKM, FPM) and silicone rubber (VQM) can be appropriately blended and used.
In consideration of kneadability of rubber materials, vulcanization moldability, and adhesion to metal plates, other types of rubber such as liquid NBR, ethylene propylene rubber (EPDM), natural rubber (NR), isoprene rubber (IR), styrene butadiene rubber (SBR), butadiene rubber (BR) and the like are also used preferably.

  As shown in FIG. 2A, the seal lip 14 (contact lip, main lip) is pressed against the inner ring 2 (side wall surface 8) as described above with the seal 11 attached to the outer ring 3, but the seal 11 Since the constricted portion 16 is formed between the inner peripheral surface 12A of the metal core 12 and the seal lip 14, the constricted portion 16 having low rigidity is mainly deformed even when the seal lip 14 is pressed against the inner ring 2. Since the constricted portion 16 absorbs errors due to the shape accuracy of each part such as the inner ring 2 and the outer ring 3 and the followability to the inner ring 2 is improved, a stable and reliable contact-type seal can be configured. In addition, the increase in rotational torque can be suppressed.

Further, the seal lip 14 has a root portion (connecting portion of the seal lip 14 to the constricted portion 16) so that the axial component of centrifugal force generated when rotating with the outer ring 3 acts outward. Since the center of gravity is located on the outer side in the axial direction, the force acting in the direction of moving the seal lip 14 outward by centrifugal force increases as the rotational speed of the outer ring 3 increases.
Therefore, as the rotational speed of the outer ring 3 increases, the lip reaction force decreases and the sliding resistance decreases, so that wear and heat generation can be kept small.
Here, when the rotational speed of the outer ring 3 exceeds a predetermined value, the thickness of the constricted portion 16, the center of gravity position, the mass, and the shape of the seal lip 14 are determined as shown in FIG. It is determined that the lip 14 is separated from the inner ring 2.

As shown in FIG. 2B, when the rotational speed of the outer ring 3 exceeds a predetermined value and the seal lip 14 is separated from the inner ring 2 by centrifugal force, the seal lip 14 is no longer a contact seal. Since the resistance by sliding and the wear of the seal lip 14 are eliminated, the rotational torque is increased when the rotational speed of the outer ring (outer member) is increased in the conventional motion seal having a structure in which the seal lip contacts the inner member. And the problem that the amount of heat generation increases as the wear amount of the seal lip increases can be solved.
Further, as shown in FIG. 2A, when the rotational speed of the outer ring 3 does not exceed a predetermined value, for example, when the rotational speed is relatively low, the rolling bearing 1 is sealed by functioning reliably as a contact seal. If the rotational speed of the outer ring 3 exceeds a predetermined value and the seal lip 14 is separated from the inner ring 2 as shown in FIG. 2B, for example, the rotational speed is relatively high, the contact seal is not used. Since the seal lip 14 functions as a non-contact seal even when the seal lip 14 is separated from the inner ring 2 and the seal lip 14 rotates at a relatively high speed, foreign matter intrudes between the inner ring 2 and the outer ring 3 and the inner ring 2 and the outer ring 3. Leakage of the grease 10 from between can be suppressed.
In addition, since the peripheral groove 6 is formed on the outer peripheral surface of the inner ring 2, the labyrinth of the non-contact seal by the seal lip 14 and the peripheral groove 6 separated from the inner ring 2 by centrifugal force as shown in FIG. Due to the effect, the sealing performance when the seal lip 14 is separated from the inner ring 2 by centrifugal force can be improved.

The predetermined value of the rotational speed of the outer ring 3 that is the outer member OP differs depending on the size, usage, required specifications, and the like. Therefore, when designing the motion seal 11, for example, by simulation such as FEM (Finite Element Method) analysis. For example, in a small-diameter bearing, it is about 10000 rpm to 20000 rpm, and in a bearing used for an automobile or the like, it is about 1000 rpm to 2000 rpm.
The centrifugal force generated by the rotation of the outer ring 3 is balanced so that the axial component of the centrifugal force generated in the seal lip is reduced as in the conventional motion seal so as to minimize the displacement of the seal lip. Since it is not necessary to make a detailed design, the design can be easily performed and the degree of freedom in design is increased.
Further, since the elastic body 13 is formed with a stop portion 17 that stops the seal lip 14 when the seal lip 14 is separated from the inner ring 2, the rotational speed of the outer ring 3 as shown in FIG. In a state where the seal lip 14 is separated from the inner ring 2 beyond the predetermined value, flapping of the seal lip 14 can be suppressed to prevent the lip from being broken and the function as a non-contact seal can be stabilized. .

3 and 4 show a rolling bearing 1 equipped with a radial contact type motion seal 11, and the same reference numerals as those in FIGS. 1 and 2 denote the same or corresponding parts.
3 and 4, the seal lip 14 having a shape different from the bifurcated seal lip 14 shown in FIGS. 1 and 2 is brought into pressure contact with the outer peripheral surface 9 of the inner ring 2 which is the inner member IP.

The seal lip 14 shown in FIGS. 3 and 4 is similar to the seal lip 14 shown in FIGS. 1 and 2 so that the axial component of centrifugal force generated when rotating together with the outer ring 3 acts outward. The center of gravity is positioned on the outer side in the axial direction from the root portion of 14 (the connecting portion of the seal lip 14 with the constricted portion 16), and the rotational speed of the outer ring 3 is predetermined from the low-speed rotation state shown in FIG. When the high speed rotation state shown in FIG. 4B is exceeded, the seal lip 14 is designed to be separated from the inner ring 2, and the elastic body 13 has a seal lip 14 when the seal lip 14 is separated from the inner ring 2. A stop portion 17 for stopping 14 is formed.
Further, since the step portion is formed by the side wall surface 8 and the outer peripheral surface 9 of the inner ring 2, a non-contact seal is formed by the seal lip 14 separated from the inner ring 2 by centrifugal force and the step portion as shown in FIG. The labyrinth effect is produced.
Therefore, even if it is the structure of the exercise | movement seal 11 shown in FIG.3 and FIG.4, there exists an effect similar to the exercise | movement seal 11 shown in FIG.1 and FIG.2.

5 and 6 show a one-way clutch 18 equipped with a radial contact type exercise seal 11, and the same reference numerals as those in FIGS. 1 to 4 denote the same or corresponding parts.
5 and 6, the connecting member 20 is attached to the inner ring 2 of the rolling bearing 1, the inner member IP is attached to the outer ring 3, the outer member OP is attached to the connecting member 20, and the outer member OP is the inner member IP. The clutch mechanism part 19 is accommodated between the inner member IP and the outer member OP, and is located on the radially outer side of the outer peripheral surface and rotates.
Further, the outer peripheral side surfaces of the exercise seals 11, 11 are positioned by being pressed by the connecting member 20 and the holding member 21, the seals 11, 11 are attached to the outer member OP, and the annular opening between the inner member IP and the outer member OP. A and A are closed, and a seal lip 14 having a shape different from the seal lip 14 of FIGS. 1 to 4 is pressed against the outer peripheral surface of the inner member IP.
Therefore, the seals 11 and 11 can suppress the entry of foreign matter into the annular openings A and A between the inner member IP and the outer member OP and the leakage of the lubricant from the clutch mechanism portion 19.

The seal lip 14 shown in FIGS. 5 and 6 is also sealed so that the axial component of centrifugal force generated when rotating together with the outer member OP acts on the outside in the same manner as the seal lip 14 shown in FIGS. The center of gravity is positioned outside the base portion of the lip 14 (the connecting portion with the constricted portion 16 of the seal lip 14) in the axial direction, and the rotational speed of the outer member OP exceeds a predetermined value and is shown in FIG. The seal lip 14 is designed to be separated from the inner member IP when it is in a rotating state, and the elastic body 13 has a stopper 17 that stops the seal lip 14 when the seal lip 14 is separated from the inner member IP. Is formed.
In the configuration shown in FIGS. 5 and 6, the circumferential groove or the stepped portion as shown in FIGS. 1 to 4 is not formed on the outer peripheral surface of the inner member 1 </ b> P. 1-4, a circumferential groove or a step portion can be formed on the outer peripheral surface of the inner member 1P, and according to such a configuration, the inner side by centrifugal force as shown in FIG. Due to the labyrinth effect of the non-contact seal formed by the seal lip 14 separated from the member IP and the circumferential groove or stepped portion, the sealing performance when the seal lip 14 is separated from the inner member IP by centrifugal force can be improved.
Therefore, even if it is the structure of the exercise | movement seal 11 shown in FIG.5 and FIG.6, there exists an effect similar to the exercise | movement seal 11 shown in FIGS.

A Ring opening IP Inner member OP Outer member 1 Rolling bearing 2 Inner ring 3 Outer ring 4 Cage 5 Rolling body 6 Inner ring circumferential groove 7 Outer ring circumferential groove 8 Side wall surface 9 Outer surface 10 Grease 11 Motion seal 12 Core 12A Inner surface 13 Elastic body 14 Seal lip 15 Outer diameter mounting portion 16 Constricted portion 17 Stopping portion 18 One-way clutch 19 Clutch mechanism portion 20 Connecting member 21 Presser member

Claims (3)

It is attached to an outer member that is positioned radially outward from the outer peripheral surface of the inner member, and closes an annular opening between the inner member and the outer member. An exercise seal with an inner peripheral side end as a seal lip,
While forming a constricted portion between the inner peripheral surface of the cored bar and the seal lip, the seal lip has a shape in which an axial component of centrifugal force acts on the outside,
With the motion seal attached to the outer member, the seal lip is pressed against the inner member,
When the rotational speed of the outer member exceeds a predetermined value, the seal lip is separated from the inner member by centrifugal force.   The exercise seal according to claim 1, wherein a stopper portion that stops the seal lip when the seal lip is separated from the inner member is formed on the elastic body. The exercise seal according to claim 1, wherein a circumferential groove or a step is formed in the inner member so that a labyrinth seal effect is obtained when the seal lip is separated from the inner member.

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