JP2014015956A - Sealing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealing device capable of restraining reversion of an auxiliary lip even when a rotation shaft is inserted from an auxiliary lip side.SOLUTION: A sealing device 1 according to the present invention comprises: a main lip in slide contact with an outer periphery of a shaft end of a crank shaft; and an auxiliary lip 7 that is provided on one side in an axial direction of the main lip and whose tip 7a on its inner peripheral side comes into slide contact with the outer periphery. The auxiliary lip 7 extends diagonally to an axial direction so that the tip 7a is positioned nearer one side in the axial direction than a base end 7b of the auxiliary lip 7. Plural projection sections 10 contacting the shaft end before the tip 7a of the auxiliary lip 7 are formed on an outside face 9 of the auxiliary lip 7 when the end is inserted from the auxiliary lip 7 side, and at the tip 7a on an inner peripheral side of the auxiliary lip 7 when the shaft end is inserted from the auxiliary lip 7 side by projecting toward one side in the axial direction from the tip 7a of the auxiliary lip 7 under a free state.

Description

  The present invention relates to a sealing device for sealing between a rotating shaft such as a crankshaft of an automobile and a casing surrounding the rotating shaft.

Conventionally, in an automobile engine, a sealing device is used to prevent leakage of lubricating oil from between a crank chamber and a front side end portion of a crankshaft penetrating the crank chamber (for example, , See Patent Document 1).
Fig.5 (a) is sectional drawing which shows the said conventional sealing device. The sealing device 100 is attached to an annular space between a crank chamber housing 101 and a crankshaft front end portion 102 (hereinafter also simply referred to as “shaft end portion 102”) protruding from the housing 101. In addition, the lubricating oil in the crank chamber is sealed from between the housing 101 and the shaft end portion 102 so as not to leak to the outside.

The sealing device 100 includes a main lip 103 that is in sliding contact with the outer peripheral surface 102 a of the shaft end portion 102, and an auxiliary lip 104 that is located on the outer side of the crank chamber with respect to the main lip 103.
The auxiliary lip 104 is provided to protect the main lip 103 from external muddy water and dust. The auxiliary lip 104 is inclined so that the distal end 104a on the inner peripheral side is located on the outer side of the crank chamber with respect to the base end 104b. It extends.

JP 2008-25654 A

In order to attach the sealing device 100 to the housing 101, generally, the sealing device 100 is inserted into the housing 101 after the sealing device 100 is externally fitted to the shaft end portion 102 protruding to the outside of the crank chamber.
Therefore, the shaft end portion 102 is introduced into the sealing device 100 from the main lip 103 side. At this time, since the auxiliary lip 104 is inclined as described above, the tip 104a of the auxiliary lip 104 slides in the axial direction with respect to the outer peripheral surface 102a of the shaft end 102 by the insertion of the shaft end 102. Even so, the auxiliary lip 104 will not be deformed excessively.

However, depending on the structure of the engine or the crankshaft, the shaft end 102 may need to be introduced into the sealing device 100 from the outside of the crank chamber, that is, from the auxiliary lip 104 side.
In such a case, the auxiliary lip 104 extends so as to be inclined such that the distal end 104a thereof is located on the outer side of the crank chamber with respect to the base end portion 104b. When it hits or catches on the end face or chamfer of 102, the tip 104a is pressed in the axial direction by the shaft end 102, and the auxiliary lip 104 is deformed to be bent as shown in FIG. So-called inversion occurs.

Further, since the sealing device 100 is in sliding contact with a crankshaft for generating a rotational force, it is required to reduce friction loss in addition to sealing performance. For this reason, the auxiliary lip 104 is set to have almost no interference with the outer peripheral surface 102 a of the shaft end portion 102.
However, in recent years, assuming that the lip 104 is used in a severe environment such as off-road, an appropriate interference may be set on the auxiliary lip 104 to promote the occurrence of the inversion.

  If the auxiliary lip 104 is reversed, the auxiliary lip 104 is damaged or deformed, and the effect of protecting the main lip 103 from external muddy water and dust is reduced, and the sealing performance of the main lip 103 is deteriorated early. . As a result, the life of the sealing device 100 is significantly reduced.

  The present invention has been made in view of such circumstances, and it is an object of the present invention to provide a sealing device capable of suppressing the reversal of the auxiliary lip even when the rotating shaft is inserted from the auxiliary lip side. And

  The present invention for achieving the above object is a sealing device for sealing between a rotating shaft and a casing surrounding the rotating shaft, and is fixed to the casing side, and is provided on an outer peripheral surface of the rotating shaft. A main lip that is in sliding contact; and an auxiliary lip that is provided on one side in the axial direction of the main lip, and that has an inner peripheral tip that is in sliding contact with the outer peripheral surface. It extends inclining with respect to the axial direction so as to be positioned on one side in the axial direction from the base end portion, and the shaft end portion of the rotating shaft is inserted from the auxiliary lip side at the distal end of the auxiliary lip. In some cases, a plurality of projecting portions that are in contact with the shaft end of the rotating shaft are formed before the tip of the auxiliary lip.

  According to the sealing device configured as described above, when the shaft end of the rotating shaft is inserted from the auxiliary lip side, the protruding portion that contacts the shaft end of the rotating shaft before the tip of the auxiliary lip However, since a plurality of auxiliary lips are formed at the tip of the auxiliary lip, when the shaft end is inserted from the auxiliary lip side, the entire circumference of the tip of the auxiliary lip comes into contact with the shaft end because there is no protrusion. In comparison, the contact area on the auxiliary lip side with respect to the shaft end can be reduced, and the frictional resistance between the auxiliary lip and the shaft end can be reduced. As a result, even if the shaft end portion of the rotating member is inserted from the auxiliary lip side, the frictional force acting to pull the tip of the auxiliary lip toward the other side in the axial direction can be reduced, and the auxiliary lip is reversed. Can be suppressed.

  In the sealing device, the protrusions are preferably formed at equal intervals along the circumferential direction. In this case, since the protrusions are arranged uniformly in the circumferential direction, the protrusions are arranged at the shaft end of the rotating member. On the other hand, the projecting portion can be reliably brought into contact.

In the sealing device, it is preferable that a surface shape of the projecting portion is a spherical surface.
In this case, when the shaft end portion of the rotating member is inserted from the auxiliary lip side, the projecting portion can slide smoothly along the outer surface of the shaft end portion. For this reason, it is suppressed that a protrusion part is caught in a shaft end part, and reversal of an auxiliary lip can be controlled more effectively.

  According to the sealing device of the present invention, even if the rotating shaft is inserted from the auxiliary lip side, it is possible to suppress the inversion of the auxiliary lip.

It is sectional drawing of the sealing device which concerns on one Embodiment of this invention. (A) is an enlarged view of the auxiliary lip in FIG. 1, and (b) is an external view showing a part when the sealing device is viewed from the outside of the crank chamber. It is a figure for demonstrating the contact state of the edge part at the time of inserting the edge part of a crankshaft into a sealing device from the axial direction one side, and an auxiliary | assistant lip, (a) is immediately after the insertion start of an edge part ( b) shows a state in which the auxiliary lip is in contact with the outer peripheral surface of the end portion. (A) is a figure for demonstrating the test for evaluating the difficulty of generating inversion, and (b) is a graph which shows the test result for evaluating the difficulty of generating inversion. (A) is sectional drawing which shows the conventional sealing device, (b) is sectional drawing for demonstrating the inversion which arises in an auxiliary | assistant lip.

Next, preferred embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a cross-sectional view of a sealing device according to an embodiment of the present invention. This sealing device 1 is used to prevent the lubricating oil from leaking from between a crank chamber (not shown) of an automobile engine and a shaft end S on the front side of the crankshaft penetrating the crank chamber. Used.
The crankshaft as a rotating shaft is surrounded by the crank chamber as a casing and is rotatably supported in the crank chamber.

The sealing device 1 is configured in an annular shape and is mounted in an annular space formed between a housing H provided in a crank chamber and a shaft end S of the crankshaft, and the crankshaft and the crank Seal between the chambers.
The sealing device 1 includes a metal cored bar 2 and a seal portion 3 made of an elastic body such as fluororubber formed on the cored bar 2 by vulcanization adhesion.

The core metal 2 is formed in an annular shape by pressing a steel plate such as SPCC. The core metal 2 has a cylindrical cylindrical portion 2a and an annular portion 2b formed by bending an end portion on one axial side of the cylindrical portion 2a radially inward, and is formed in an L-shaped cross section. ing.
The seal portion 3 has a main body portion 4 that is bonded and formed along the outer surface of the annular portion 2b from the outer peripheral surface of the cylindrical portion 2a, and a lip portion 5 that extends from the tip of the annular portion 2b.
The core metal 2 is press-fitted into the housing H via the main body 4, and the sealing device 1 is fixed to the housing H.

The lip portion 5 includes an annular main lip 6 extending from the distal end of the annular portion 2b to the other side in the axial direction, and an annular auxiliary lip 7 projecting radially inward from the vicinity of the distal end of the annular portion 2b. And have.
A garter spring 8 is mounted on the outer peripheral surface side of the main lip 6 to press the main lip 6 radially inward to enhance the sealing performance.

  The main lip 6 is formed in a mountain-shaped cross-sectional shape protruding inward in the radial direction. The main lip 6 is cranked from between the rotating shaft end S and the housing H by sliding the annular sliding contact portion 6a, which is the angled tip, to the outer peripheral surface S1 of the shaft end S of the crankshaft. It is sealed so that the indoor lubricating oil does not leak to the outside.

The auxiliary lip 7 is provided on one axial side of the main lip 6. The auxiliary lip 7 extends so as to be inclined with respect to the axial direction so that the distal end 7 a is located on one side in the axial direction with respect to the base end portion 7 b of the auxiliary lip 7.
The tip 7a of the auxiliary lip 7 is formed with an annular sliding contact portion 7c that is in sliding contact with the outer peripheral surface S1 of the shaft end S. The auxiliary lip 7 seals between the outside and the main lip 6. Yes. As a result, the auxiliary lip 7 protects the main lip 6 from external muddy water and dust, and suppresses early deterioration of the sealing performance of the main lip 6.
As described above, the sealing device 1 seals between the crankshaft and the crank chamber by bringing the main lip 6 and the auxiliary lip 7 into sliding contact with the shaft end S of the crankshaft.

2A is an enlarged view of the auxiliary lip 7 in FIG. 1, and FIG. 2B is an external view showing a part when the sealing device 1 is viewed from the outside of the crank chamber. 2A shows the auxiliary lip 7 in a free state.
A plurality of protrusions 10 are formed at the tip 7 a of the auxiliary lip 7. The protruding portion 10 is formed to protrude from the outer surface 9 facing the one side in the axial direction of the auxiliary lip 7 and the edge surface 11 of the tip 7 a of the auxiliary lip 7.
Thereby, the protrusion part 10 protrudes in the axial direction one side from the front-end | tip 7a of the auxiliary | assistant lip 7 in a free state.

The protrusion 10 is formed into a spherical surface having a surface shape with a radius of about 0.3 mm.
If the inner diameter of the sliding contact portions 6a and 7c of the sealing device 1 of the present embodiment is set to about 40 mm and the thickness of the auxiliary lip 7 is set to about 0.6 to 0.7 mm, from the inner peripheral end of the protruding portion 10. The radial width dimension H1 to the sliding contact portion 7c of the auxiliary lip 7 is set to about 0.03 mm. In addition, the protrusion dimension H2 of the protrusion 10 that protrudes in one axial direction relative to the tip 7a of the auxiliary lip 7 in the free state is set to about 0.05 mm.

As shown in FIG. 2B, the protrusions 10 are formed at equal intervals along the circumferential direction. The protrusion 10 is formed at 48 locations in the circumferential direction. Therefore, the protrusions 10 are formed at equal intervals so that the angular interval D in the circumferential direction is 7.5 degrees. Moreover, the width dimension W of the circumferential direction of the protrusion part 10 is set to about 0.6 mm.
In the case of the present embodiment, since the inner diameter of the sliding contact portion 7c is set to about 40 mm as described above, the protruding portion 10 is formed at a ratio of about 23% with respect to the entire circumference.

  According to the sealing device 1 having the above-described configuration, since a plurality of protruding portions 10 that protrude in the axial direction from the tip 7a of the auxiliary lip 7 in the free state are formed on the tip 7a of the auxiliary lip 7, When the shaft end S of the crankshaft is inserted from the side, that is, the auxiliary lip 7 side, the protrusion 10 formed on the auxiliary lip 7 first contacts the shaft end S. For this reason, the contact area on the side of the auxiliary lip 7 with respect to the shaft end S can be reduced compared to the case where the entire circumference of the tip 7a of the auxiliary lip 7 is in contact with the shaft end S due to the absence of the protruding portion 10. it can.

  FIG. 3 illustrates a contact state between the shaft end S and the auxiliary lip 7 when the shaft end S of the crankshaft is inserted into the sealing device 1 from the auxiliary lip 7 side (one side in the axial direction). (A) shows the state in which the auxiliary lip 7 is in contact with the outer peripheral surface S1 of the shaft end S immediately after the insertion of the shaft end S is started.

  As shown in FIG. 3A, when the insertion of the shaft end S from the auxiliary lip 7 side is started, first, the protruding portion that protrudes from the tip 7a (the end face 11) of the auxiliary lip 7 to the one side in the axial direction. 10 contacts the chamfered portion S2 formed at the tip of the shaft end portion S. Therefore, the edge surface 11 of the tip 7a of the auxiliary lip 7 does not contact the chamfered portion S2.

If the protrusion 10 is not formed on the tip 7a of the auxiliary lip 7, the entire circumference of the tip 7a (the end edge surface 11) of the auxiliary lip 7 contacts the chamfered portion S2.
On the other hand, in this embodiment, since the plurality of protruding portions 10 are formed at equal intervals along the circumferential direction at the tip 7a of the auxiliary lip 7, the plurality of protruding portions 10 come into contact with the chamfered portion S2. Thereby, compared with the case where the perimeter of the front-end | tip 7a of the auxiliary | assistant lip 7 contacts the chamfer part S2, the contact area by the side of the auxiliary | assistant lip 7 with respect to the axial edge part S can be decreased.

  Thereby, the frictional resistance between the auxiliary lip 7 and the shaft end portion S can be reduced. As a result, even if the shaft end S of the crankshaft is inserted from the auxiliary lip 7 side, the frictional force acting to pull the tip 7a of the auxiliary lip 7 to the other side in the axial direction can be reduced. It is possible to suppress the deformation and inversion so that the vicinity of 7a is bent.

  As described above, according to the sealing device 1 configured as described above, when the shaft end S is inserted from the auxiliary lip 7 side, the protrusion that contacts the shaft end S before the tip 7a of the auxiliary lip 7 is inserted. Since a plurality of the portions 10 are formed at the tip 7a of the auxiliary lip 7, it is possible to prevent the auxiliary lip 7 from being inverted when the shaft end S is inserted from the auxiliary lip 7 side.

  Moreover, since the surface shape of the protrusion part 10 is formed in the spherical surface, when the shaft end part S is inserted from the auxiliary lip 7 side as shown in FIG. It can slide smoothly along the chamfered portion S2 and the outer peripheral surface S1. For this reason, it is suppressed that the protrusion part 10 is hooked on the axial end part S, and the inversion of the auxiliary lip 7 can be suppressed more effectively.

When the shaft end S is further inserted into the sealing device 1, the protruding portion 10 of the auxiliary lip 7 slides smoothly along the chamfered portion S2 of the shaft end S. The tip 7a of the auxiliary lip 7 is gradually enlarged in diameter as the protrusion 10 slides on the shaft end S.
Thereafter, the tip 7a of the auxiliary lip 7 is expanded in diameter until the sliding contact portion 7c contacts the outer peripheral surface S1, as shown in FIG. 3 (b).

The protruding portion 10 of the present embodiment protrudes from the distal end 7a of the auxiliary lip 7 in the free state to the one side in the axial direction without preventing the distal end 7a of the auxiliary lip 7 from slidingly contacting the outer peripheral surface S1 of the shaft end S. It is formed to do.
Therefore, as shown in FIG. 3B, the auxiliary lip 7 can make the sliding contact portion 7c slide in contact with the outer peripheral surface S1 without being obstructed by the protruding portion 10, and seal between the outer peripheral surface S1. Can do.

  As described above, in the present embodiment, the shaft end S of the crankshaft can be inserted from the auxiliary lip 7 side while suppressing the occurrence of reversal of the auxiliary lip 7 by providing the protrusion 10 at the tip 7a. .

  Moreover, in the said embodiment, since the protrusion part 10 is equally arranged in the circumferential direction by being formed in the circumferential direction at equal intervals, it protrudes with respect to the axial end part S of a crankshaft. The part 10 can be reliably brought into contact.

  Here, as described above, the ratio of the protrusion 10 of the present embodiment to the entire circumference of the auxiliary lip 7 is about 23%, but the ratio of the protrusion 10 to the entire circumference of the auxiliary lip 7 is 50%. If exceeded, the contact area of the protrusion 10 with respect to the shaft end S increases, and the protrusion 10 causes a frictional force to pull the tip 7a of the auxiliary lip 7 to the other side in the axial direction. turn into. For this reason, it is preferable that the ratio with respect to the perimeter of the protrusion part 10 is 50% or less.

Further, if the ratio of the protrusion 10 to the entire circumference is extremely small, the protrusion 10 contacts the shaft end S or the tip 7a of the auxiliary lip 7 for each part in the circumferential direction of the auxiliary lip 7. Thus, there is a possibility that the projecting portion 10 cannot be stably brought into contact with the shaft end portion S, and as a result, the frictional force that pulls the tip 7a of the auxiliary lip 7 toward the other side in the axial direction cannot be reduced. .
For this reason, it is preferable to set the ratio with respect to the perimeter of the protrusion part 10 to a value of 20% or more.

  The present invention is not limited to the above embodiment. In the said embodiment, although the case where the surface shape of the protrusion part 10 was formed in the spherical surface was illustrated, you may form the protrusion part 10 in cylindrical shape, for example. In this case, the protrusion 10 can be arranged so that its cylindrical center is along the circumferential direction of the auxiliary lip 7, thereby reducing the frictional force acting to pull the tip of the auxiliary lip toward the other side in the axial direction. Can be prevented from inverting.

  Moreover, in the said embodiment, although the sealing device which concerns on this invention was used in order to seal between the crank chamber of a motor vehicle engine, and the edge part of the crankshaft protruded from the crank chamber, it is limited to this. It is not a thing. The sealing device of the present invention can be suitably used for applications in which a rotating member is inserted from the outside of the casing on the auxiliary lip side and the space between the rotating member and the casing is sealed.

The sealing device of the present invention can also be used as a side seal of a differential gear, for example.
The side seal is a sealing device for sealing between a differential gear casing and drive shafts inserted on the left and right sides of the casing. A drive shaft as a rotating member is inserted from the outside of the casing. Since the side seal is mounted such that the auxiliary lip is located outside the casing, the drive shaft is inserted from the auxiliary lip side when inserted into the casing. Therefore, in the side seal, the auxiliary lip may be reversed.
On the other hand, if the sealing device of the present invention is applied to the side seal, the auxiliary lip can be prevented from being reversed.

Next, the results of a test for evaluating the difficulty of inversion using the sealing device 1 of the above embodiment will be described.
For the test, the sealing device 1 described in the above embodiment was used as an example product, and the sealing device 1 of the above embodiment was used as a comparative example product, except that the protruding portion 10 was not formed on the auxiliary lip 7. A sealing device having the same specifications as the above was used.

As a test method, it was evaluated whether reversal occurred by actually inserting the shaft end S of the crankshaft into the sealing device 1.
More specifically, as shown in FIG. 4A, the shaft end S of the crankshaft was inserted from the auxiliary lip 7 side of the sealing device 1. Moreover, three types of sealing devices 1 set to 0.3 mm, 0.45 mm, and 0.6 mm as interference of the auxiliary lip 7 were prepared.
Further, in order to evaluate the difficulty of inversion, the amount of eccentricity E between the shaft center of the sealing device 1 and the shaft center of the shaft end portion S when the shaft end portion S is inserted into the sealing device 1 is changed. Then, the eccentricity limit amount, which is the minimum eccentricity in which inversion occurred, was determined.

FIG. 4B is a graph showing test results for evaluating the difficulty of inversion. In FIG. 4B, the horizontal axis indicates the interference of the auxiliary lip. The vertical axis represents the eccentricity limit amount.
As shown in the figure, in the comparative product, the eccentricity limit amount was 0 mm regardless of the interference, and the reversal occurred even if the eccentricity was not performed.

  On the other hand, in the example product, when the interference is 0.3 mm and 0.45 mm, the eccentricity limit amount is about 3 mm. In this case, if the eccentricity value is smaller than 3 mm, no inversion occurred. Furthermore, even when the interference is 0.6 mm, the eccentricity limit amount is 2.5 mm or more, and it has been clarified that reversal hardly occurs at any interference as compared with the comparative product.

  As described above, from the result of the evaluation test, according to the sealing device of the present invention, even if the end of the rotating member is inserted from the auxiliary lip side by providing the protruding portion on the auxiliary lip, It was revealed that the inversion can be suppressed.

1: Sealing device 6: Main lip 7: Auxiliary lip 7a: Tip 7b: Base end 9: Outer surface 10: Projection S: Shaft end S1: Outer surface

Claims (3)

A sealing device for sealing between a rotating shaft and a casing surrounding the rotating shaft,
A main lip fixed to the casing side and in sliding contact with the outer peripheral surface of the rotating shaft;
An auxiliary lip provided on one side in the axial direction of the main lip, the tip of the inner peripheral side thereof being in sliding contact with the outer peripheral surface,
The auxiliary lip extends while being inclined with respect to the axial direction so that the distal end is positioned on one axial side of the base end portion of the auxiliary lip,
When the shaft end of the rotating shaft is inserted from the auxiliary lip side, the shaft end of the rotating shaft comes into contact with the shaft end of the rotating shaft at the tip on the inner peripheral side of the auxiliary lip. A sealing device, wherein a plurality of protrusions are formed.   The sealing device according to claim 1, wherein the protrusions are formed at equal intervals along a circumferential direction.   The sealing device according to claim 1, wherein a surface shape of the projecting portion is a spherical surface.

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