WO2015004963A1

WO2015004963A1 - Shaft seal

Info

Publication number: WO2015004963A1
Application number: PCT/JP2014/059760
Authority: WO
Inventors: 卯ノ田　和史; 尚彦本井伝; 敦細川
Original assignee: 三菱電線工業株式会社
Priority date: 2013-07-09
Filing date: 2014-04-02
Publication date: 2015-01-15
Also published as: TWI522555B; CN105008776A; JP6088374B2; KR20160030070A; JP2015017626A; TW201502399A; CN105008776B

Abstract

Provided is a shaft seal configured so that the lifting of a dust lip while the shaft seal is under pressure can be prevented. A shaft seal is mounted in an annular groove (2) formed in an insertion hole (20) penetrating through a female body (B) and is in sliding contact with the outer peripheral surface (1A) of a shaft member (1) inserted into the insertion hole (20) so as to be capable of reciprocating, the annular groove (2) comprising a first side wall surface (13) which is located on the pressure receiving side (R), a second side wall surface (12) which is located on the low pressure side (L), and a groove bottom surface (14). The shaft seal is provided with: a U-shaped seal section (10) located on the pressure receiving side (R) and comprising an inner peripheral lip (3) and an outer peripheral lip (4); and a dust lip (7) protruding to the low pressure side (L). A protrusion is formed on a low pressure-side outer peripheral corner (8) formed between an outer peripheral surface (15) in contact with the groove bottom surface (14) and a support surface (6) facing the second side wall surface (12), and while the shaft seal is under pressure, the protrusion is pressed against the corner (16) between the groove bottom surface (14) and the second side wall surface (12) and is absorbed by the low pressure-side outer peripheral corner (8) due to elastic compressive deformation.

Description

Shaft seal

The present invention relates to a shaft seal.

Conventionally, as illustrated in FIG. 10, a shaft seal (as a single seal) that is used in a pneumatic device such as a cylinder or a valve and integrally includes a U-shaped seal portion 42 and a dust strip 47. A shaft seal that is mounted in the annular groove 50 of the head or the valve body and slidably contacts the shaft member 41 (such as a rod or a spool) that reciprocates is known.
By the way, in the conventional shaft seal shown in FIG. 10, the inner peripheral lip 43 and the outer peripheral lip 44 have a shape (H ₄₃ = 0 in FIG. 10) in which the axial center positions (of the shaft member 41) coincide with each other. As shown in FIG. 10 (B), the U-shaped concave groove portion 55 between the inner and outer

peripheral lips

43, 44 is adsorbed to the side wall portion 51 of the annular groove 50, and the sealing performance is lost. As in G, there was a problem of causing blow-off.
As a countermeasure against this, as shown in FIGS. 8 and 9, a cross-sectional shape is known in which the inner peripheral lip 43 is shortened and a dimensional difference H ₄₃ is provided between the inner peripheral lip 43 and the outer peripheral lip 44. (See Patent Document 1).

Japanese Utility Model Publication No. 60-14356

As shown in FIGS. 8 and 9, the conventional shaft seal 40 of Patent Document 1 or the like has a U-shaped seal portion 42 composed of an inner peripheral lip 43 and an outer peripheral lip 44 protruding in the direction of arrow R (hereinafter referred to as pressure receiving side R). And a sliding dust strip 47 projecting in the direction of the arrow L (hereinafter referred to as the low pressure side L), and a projecting portion 45 is formed on the outer surface of the outer peripheral lip 44. As shown in FIG. 9, the shaft seal 40 is mounted in an annular groove 50 of a female body B (such as a cylinder head) through which an insertion hole through which the shaft member 41 is reciprocally inserted is inserted. 41 is in sliding contact with the outer peripheral surface 41A. The annular groove 50 has a first side wall surface 51 on the pressure receiving side R, a second side wall surface 52 on the low pressure side L, and a groove bottom surface 53. In a state where the shaft seal 40 is mounted in the annular groove 50, the outer peripheral surface portion 49 of the shaft seal 40 contacts the groove bottom surface 53, and the support surface portion 46 formed on the low pressure side L of the shaft seal 40 is formed on the second side wall surface 52. Face to face.

In the pressure receiving state shown in FIG. 9, the shaft seal 40 receives pressure from the U-shaped seal portion 42 and is pressed from the pressure receiving side R toward the low pressure side L. At this time, the support surface portion 46 is pressed against the second side wall surface 52, and the dust lip 47 moves in volume inside the shaft seal 40 so as to enter the clearance between the female body B and the shaft member 41, and the corner portion P ( A rotational moment M is generated with the second side wall surface 52 side as a fulcrum. In addition, the rotational moment M increases due to the dimensional difference H ₄₃ and the short inner peripheral lip 43. Due to distortion (elastic deformation) due to the rotational moment M, the dust lip 47 may be lifted off the shaft member 41. When the dust lip 47 is lifted, the contact surface pressure with the shaft member 41 becomes zero (see graph (i) in FIG. 9), or the dust lip 47 leaves the shaft member 41 with a gap g. End up. Thus, in the pressure receiving state, the conventional shaft seal 40 has the problem that the dust lip 47 loses its sealing property and the grease retaining property deteriorates.
Further, due to the lifting of the dust strip 47, there is a drawback that the eccentricity followability is lowered and the dust resistance is lowered. Furthermore, the sliding contact resistance of the inner peripheral lip 43 becomes excessive, or the belly surface 48 of the shaft seal 40 comes into contact with the shaft member 41 to cause the sliding contact resistance to be excessive.

Therefore, an object of the present invention is to provide a shaft seal capable of preventing the dust lip from being lifted under a pressure-receiving state (while preventing the above-described suction leakage).

The shaft seal according to the present invention is attached to the annular groove of the female body through which an insertion hole having an annular groove composed of a pressure-receiving side first side wall surface, a low-pressure side second side wall surface, and a groove bottom surface is provided. A shaft seal that is in sliding contact with the outer peripheral surface of a shaft member that is reciprocally inserted into the insertion hole, the pressure receiving side U-shaped seal portion including an inner peripheral lip and an outer peripheral lip, and a dust lip that protrudes toward the low pressure side In the shaft seal provided, a protruding portion is formed on the low pressure side outer peripheral corner formed by the outer peripheral surface portion contacting the groove bottom surface and the support surface portion facing the second side wall surface, and is in a pressure receiving state. Thus, the protrusion is pressed against the groove bottom and the corner of the second side wall surface, and the protrusion is absorbed by the low-pressure side outer peripheral corner by elastic compression deformation.
Further, in the pressure receiving state, with the corner portion of the second side wall surface and the insertion hole as a fulcrum, the dust lip rises due to the generated rotational moment to the radially inward direction generated by the elastic compression deformation of the protrusion. It is constructed so as to prevent it by the impact force.

According to the shaft seal of the present invention, it is possible to prevent the dust lip from being lifted from the shaft member by the elastic reaction biasing force generated by the elastic compression deformation of the protrusion in the pressure receiving state. Along with the prevention of the lifting, the dust intrusion prevention performance (also referred to as dust resistance) is improved, and the grease retention can be improved. Moreover, it is possible to prevent the dropout from the annular groove. Furthermore, in pneumatic equipment or the like in which the dimensional accuracy of the annular groove and the dimensional accuracy of the shaft member are low, and the hole axis and the shaft member axis are eccentric, Excellent dust resistance, sealing performance and grease retention.

It is sectional drawing which showed one Embodiment of this invention in the free state. It is a figure which shows the cross-sectional shape and surface pressure distribution of a pressure-receiving state, Comprising: Graph (i) is a figure which shows the surface pressure distribution of a shaft member and a dust lip, Graph (ii) shows a support surface part and a 2nd side wall surface. It is a figure which shows surface pressure distribution, and graph (iii) is a figure which shows surface pressure distribution of an outer peripheral surface part and a groove bottom face. It is a perspective view partially broken and shown. It is sectional drawing which showed other embodiment of this invention in the free state. It is a figure which shows the cross-sectional shape and surface pressure distribution of a pressure-receiving state, Comprising: Graph (i) is a figure which shows the surface pressure distribution of a shaft member and a dust lip, Graph (ii) shows a support surface part and a 2nd side wall surface. It is a figure which shows surface pressure distribution, and graph (iii) is a figure which shows surface pressure distribution of an outer peripheral surface part and a groove bottom face. It is sectional drawing which showed another embodiment of this invention in the free state. It is sectional drawing which showed the Example of the protrusion part, (a) is sectional drawing of another Example, (b) is sectional drawing of another Example, (c) is another Example. FIG. It is sectional drawing which showed the free state of the conventional shaft seal. It is a figure which shows the cross-sectional shape and surface pressure distribution of the pressure receiving state of the conventional shaft seal, Comprising: Graph (i) is a figure which shows the surface pressure distribution of a shaft member and a dust lip, Graph (ii) is a support surface part. It is a figure which shows the surface pressure distribution of a 2nd side wall surface, and a graph (iii) is a figure which shows the surface pressure distribution of an outer peripheral surface part and a groove bottom face. It is sectional drawing of the conventional shaft seal.

Hereinafter, the present invention will be described in detail with reference to the drawings illustrating embodiments.
The shaft seal of the present invention is used in a reciprocating part such as a cylinder or a valve of a pneumatic device. As shown in FIGS. 1 to 3, an insertion hole 20 having an annular groove 2 composed of a first side wall surface 13 on the pressure receiving side (high pressure side) R, a second side wall surface 12 on the low pressure side L, and a groove bottom surface 14. The shaft seal is attached to the annular groove 2 of the penetrating female body B and slidably contacts the outer peripheral surface 1A of the shaft member 1 inserted in the insertion hole 20 so as to reciprocate. In the present invention, the female body B is a cylinder head or a valve body, and the shaft member 1 is a rod or a spool. In the insertion hole 20 of the female body B, the clearance C 2 on the low pressure side L of the annular groove ₂ is set larger than the clearance C ₁ on the pressure receiving side R of the annular groove 2. This is because, on the low pressure side L of the annular groove 2, the dust lip 7 is inserted between the female body B and the outer peripheral surface 1 </ b> A of the shaft member 1 and is brought into sliding contact with the outer peripheral surface 1 </ b> A of the shaft member 1. . The shaft seal of the present invention can be used not only for pneumatic equipment but also for hydraulic equipment as long as it is for low pressure. A rubber-based material is used as the material of the shaft seal.

The shaft seal of the present invention includes a U-shaped seal portion 10 composed of an inner peripheral lip 3 and an outer peripheral lip 4 projecting to the pressure receiving side R, and a dust lip 7 projecting to the low pressure side L.
In the pressure receiving state shown in FIG. 2, the U-shaped seal portion 10 receives pressure from the inner peripheral lip 3 and the outer peripheral lip 4 so that the inner peripheral lip 3 is in sliding contact with the outer peripheral surface 1 </ b> A of the shaft member 1. 4 (and the outer peripheral surface portion 15) are in close contact with the groove bottom surface 14. A protruding portion 5 is provided on the outer surface of the outer peripheral lip 4 in a free state. A concave inner peripheral abdomen 11 is formed on the inner peripheral surface between the inner peripheral lip 3 and the dust lip 7, and grease is sealed between the shaft member 1 by the inner peripheral lip 3, the dust lip 7 and the inner peripheral abdomen 11. Chamber 17 can be formed.

As shown in FIGS. 1 and 3, the shaft seal of the present invention has a low-pressure-side outer peripheral corner formed by an outer peripheral surface portion 15 that contacts the groove bottom surface 14 and a support surface portion 6 that faces the second side wall surface 12. 8, a protrusion 9 is formed. The protrusion 9 is formed in an arc shape in cross section, and protrudes (bulges out) to the outer peripheral surface 15 side of the low pressure side outer peripheral corner 8.
In the pressure receiving state shown in FIG. 2, the low pressure side outer peripheral corner 8 is pressed against the groove bottom surface 14 and the corner 16 of the second side wall surface 12, and the projection 9 is absorbed by the low pressure side outer peripheral corner 8 by elastic compression deformation. Is done. In other words, the protrusion 9 is compressed (elastically deformed) between the low pressure side outer peripheral corner 8 and the corner 16 and the low pressure side outer peripheral corner 8 and the corner 16 are in close contact with each other.
In the pressure receiving state, the U-shaped seal portion 10 receives pressure and is pressed from the pressure receiving side R toward the low pressure side L, and the support surface portion 6 is pressed against the second side wall surface 12. At this time, since a relatively large clearance C ₂ of the low-pressure side L of the annular groove 2, than the depth D ₁₃ of the depth D ₁₂ of the low-pressure side second sidewall surface 12 (pressure receiving side first side wall surface 13 ) Due to the pressure received by the U-shaped seal portion 10 that is small and has a large depth dimension D, a rotational moment M is generated with the corner portion P as a fulcrum. In other words, it is set larger clearance C ₂ for dust lip 7, the fluid pressure acts from the entire depth D to the left in FIG. With respect to this fluid pressure, the second side wall surface 12 is unevenly distributed radially outward (due to the presence of the clearance C ₂ ), and is received by the unevenly distributed second side wall surface 12. Therefore, the entire shaft seal receives the rotational moment M.
(As in the conventional seal shown in FIG. 9) by the occurrence of rotational moment M as described above, the dust lip 7 is going Ukiagaro as arrow M _7.
However, in the pressure receiving state shown in FIG. 2, the protruding portion 9 of FIG. 1 is elastically compressed and deformed until it matches the shape of the groove bottom surface 14 of the annular groove 2, and the radial inward direction indicated by the arrow F in FIG. Generates a repulsive biasing force. This elastic reaction urging force F, preventing uplift M ₇ dust lip 7 from the shaft member 1. That is, the elastic reaction force F not only counteract the arrow M ₇ force to be Ukiagaro is dust lip 7, further pressed in the radial inward direction, indicated by the graph (i) in FIG. 2 surface Maintain contact with pressure.

As shown in the graph (ii) of FIG. 2, a surface pressure peak (vertex) occurs at the corner P between the second side wall surface 12 and the support surface portion 6. On the other hand, as shown in the graph (iii), at the groove bottom surface 14 and the outer peripheral surface portion 15, a high surface pressure P ₉ is generated in the vicinity of the corner portion 16 due to the repulsive force of the projection portion 9. This high surface pressure P ₉ is it that is causing the resilient anti-biasing force F described above. In this way, the lift M ₇ caused by the rotational moment M around the corner portion P in the pressure receiving state can be prevented by the elastic reaction biasing force F. As a result, it can be seen that in the pressure receiving state, the shaft member 1 and the dust lip 7 are in sliding contact with an appropriate mountain-shaped surface pressure distribution as shown in the graph (i).

With respect to the depth dimension D of the annular groove 2 from the shaft member 1 to the groove bottom surface 14, the height dimension H from the inner peripheral abdomen 11 to the tip of the protrusion 9 in the free state is set slightly smaller. It is constituted so that it may not fall off from the low pressure side L. In the pressure receiving state, the protrusion 9 is absorbed by the low pressure side outer peripheral corner 8 by elastic compression deformation, so that the inner peripheral abdomen 11 is the shaft member even if the height dimension H is slightly different from the depth dimension D. 1 can be avoided, and sliding is possible with low friction.

Next, another embodiment of the present invention will be described.
As shown in FIG. 4, the protrusion 9 formed on the low pressure side outer peripheral corner 8 protrudes (bulges out) toward the support surface 6 of the low pressure side outer peripheral corner 8. Since other configurations are the same as those of the above-described embodiment, description thereof is omitted.
As shown in FIG. 5, in the pressure receiving state, the U-shaped seal portion 10 receives pressure, the projection 9 is pressed against the second side wall surface 12, and the projection 9 is elastically compressed and deformed to the low pressure side outer peripheral corner. 8 is absorbed (in cross-sectional shape). As shown in the graph (ii), the surface pressure increases in the vicinity of the corner 16 due to the repulsive force of the protrusion 9, and shows a peak Pmax. The low pressure side outer peripheral corner portion 8 is pressed against the groove bottom surface 14 and the corner portion 16 of the second side wall surface 12, and the vicinity of the corner portion 16 as shown in the graph (iii) by volume movement due to elastic compression deformation of the protrusion portion 9. low-pressure side circumference edge 8 is in contact strongly the groove bottom surface 14 at, shows a surface pressure P _9, by the elastic reaction force F in the radial in the direction indicated by an arrow, M ₇ Ri floating dust lip 7 Is maintained and an appropriate surface pressure is maintained as shown in the graph (i). Thus, the lift M ₇ of the dust lip 7 from the shaft member 1 caused by the rotational moment M around the corner P in the pressure receiving state is prevented. As a result, in the pressure receiving state, the shaft member 1 and the dust lip 7 are in sliding contact with an appropriate mountain-shaped surface pressure distribution as shown in the graph (i).

FIG. 6 shows another embodiment of the present invention.
As shown in FIG. 6, it is also desirable to form oblique projections 9 projecting (expanding) on the outer peripheral surface portion 15 side and the support surface portion 6 side on the low pressure side outer peripheral corner portion 8. In the pressure receiving state, as in FIG. 2, the protrusion 9 is pressed against the groove bottom surface 14 and the corner 16 of the second side wall surface 12 and is absorbed by the low pressure side outer peripheral corner 8 by elastic compression deformation. Other configurations are the same as those of the above-described embodiment.

The design of the present invention can be changed. For example, as shown in FIG. 7A, the protrusion 9 may have a quadrangular end surface. Or it is good also as trapezoid shape of FIG.7 (b), or it is also preferable to set it as the triangular shape of FIG.7 (c).
In FIG. 3, the protrusions 9 are continuously formed on the circumference. However, the protrusions 9 are not limited to this embodiment, and are preferably formed intermittently (not shown).

As described above, the shaft seal according to the present invention is provided with the insertion hole 20 having the annular groove 2 including the first side wall surface 13 on the pressure receiving side R, the second side wall surface 12 on the low pressure side L, and the groove bottom surface 14. A shaft seal that is attached to the annular groove 2 of the female body B and is slidably contacted with the outer peripheral surface 1A of the shaft member 1 that is inserted in the insertion hole 20 so as to be reciprocally movable. A shaft seal provided with a U-shaped seal portion 10 on the pressure side R and a dust strip 7 projecting toward the low pressure side L, and an outer peripheral surface portion 15 that contacts the groove bottom surface 14 and a support that faces the second side wall surface 12. The protrusion 9 is formed on the low-pressure side outer peripheral corner 8 formed by the surface 6 and is pressed against the groove bottom surface 14 and the corner 16 of the second side wall surface 12 in the pressure receiving state, so that the protrusion 9 is elastically deformed. So that the protrusion is absorbed in the low pressure side outer peripheral corner portion 8 in the pressure receiving state. By the elastic compressive deformation of 9, by generating elastic reaction force F in the radial inward direction, in a reaction force F, thereby preventing floating of the dust lip 7 from the shaft member 1. As a result, the grease retention is improved and the sliding contact resistance can be reduced. Further, the eccentricity followability of the dust lip 7 can be maintained, and the dust resistance and grease retention can be improved. Furthermore, it is possible to prevent the dropout from the annular groove 2.

Further, in the pressure receiving state, with the corner portion P between the second side wall surface 12 and the insertion hole 20 as a fulcrum, the lift M ₇ of the dust lip 7 due to the generated rotational moment M is caused by the radial compressive deformation of the protrusion 9. Since it is configured to prevent it by the inward impact and repulsive force F, it achieves the desired purpose with a simple configuration, prevents dust lip lifting, has excellent eccentricity tracking, and retains grease. Also excellent in properties.

DESCRIPTION OF SYMBOLS 1 Shaft member 1A Outer peripheral surface 2 Annular groove 3 Inner peripheral lip 4 Outer peripheral lip 6 Support surface part 7 Dustrip 8 Low pressure side outer peripheral corner part 9 Projection part 10 U-shaped seal part 12 2nd side wall surface 13 1st side wall surface
14 groove bottom surface 15 outer peripheral surface portion 16 corner portion 20 insertion hole F elastic reaction biasing force R pressure receiving side L low pressure side B female body P corner portion M rotational moment M ₇ lift

Claims

An insertion hole (20) having an annular groove (2) comprising a first side wall surface (13) on the pressure receiving side (R), a second side wall surface (12) on the low pressure side (L) and a bottom surface (14) of the groove is provided. A shaft seal that is attached to the annular groove (2) of the female body (B) and is slidably contacted with the outer peripheral surface (1A) of the shaft member (1) that is reciprocally inserted into the insertion hole (20). And a U-shaped seal portion (10) on the pressure receiving side (R) comprising an inner peripheral lip (3) and an outer peripheral lip (4), and a dust lip (7) protruding to the low pressure side (L). In the shaft seal
On the low pressure side outer peripheral corner (8) formed by the outer peripheral surface portion (15) contacting the groove bottom surface (14) and the support surface portion (6) facing the second side wall surface (12), the protrusion (9 )
In the pressure receiving state, the protrusion (9) is pressed against the groove bottom surface (14) and the corner (16) of the second side wall surface (12), and the protrusion (9) is elastically deformed to cause the low pressure side outer peripheral corner (8). The shaft seal is configured to be absorbed by the shaft.
In the pressure receiving state, the dust lip (7) is lifted (M 7 ) by the generated rotational moment (M) with the corner (P) of the second side wall surface (12) and the insertion hole (20) as a fulcrum. 2. The shaft seal according to claim 1, wherein the shaft seal is configured to be prevented by an elastic repulsion force (F) in a radial inward direction generated by the elastic compression deformation of the protrusion (9).