CN213598577U - Sealing device and sealing structure - Google Patents

Abstract

The utility model provides a sealing device and seal structure, it can block the backpressure and realize energy-conservation. A sealing device (1) is an annular sealing device for sealing between a through hole (101) of a cylindrical member (100) and a shaft (200) inserted into the through hole (101), and comprises: a main lip (21) that contacts the outer peripheral surface (201) of the shaft (200); and a back pressure lip (22) formed on the opposite side of the space (A1) to be sealed in the direction of the axis (x) with the main lip (21) therebetween. The back pressure lip (22) extends obliquely so as to be spaced apart from a space to be sealed (A1) as it approaches an outer peripheral surface (201) of the shaft (200), and is formed so as to form a gap between the back pressure lip and the outer peripheral surface (201) of the shaft (200), and the value of the dimension (T) of the back pressure lip in a direction orthogonal to the direction in which the back pressure lip extends divided by the dimension (L) of the back pressure lip in the axial direction is 0.9 or less.

Description

Sealing device and sealing structure

Technical Field

The utility model relates to a sealing device and seal structure especially relate to a sealing device and seal structure for carrying out reciprocating motion's axle.

Background

Conventionally, a sealing device such as a seal ring is used to seal a gap between a shaft that reciprocates, for example, rotationally or linearly, and a through hole into which the shaft is inserted. The sealing device is provided with a sealing device which prevents the lubricant as the object to be sealed in the device from leaking to the outside and prevents foreign matters such as liquid and dust from entering the device from the atmosphere side. As such a conventional sealing device, a guide rod seal has been proposed which prevents oil from leaking between a guide rod and a valve guide of an internal combustion engine (see, for example, patent document 1).

The guide rod seal described in patent document 1 is provided with an internal pressure seal body that is always in sliding contact with the valve guide system, in addition to a seal lip that can leak a suitable amount of oil in order to prevent the guide rod and the valve guide from melting. By providing such an internal pressure seal body, exhaust gas from the exhaust port into the cylinder head cover is sealed, and an increase in the diameter of the seal lip due to high-pressure exhaust gas is suppressed.

(Prior art document)

(patent document)

Patent document 1: JPH 10-205623A.

SUMMERY OF THE UTILITY MODEL

(problem to be solved by utility model)

However, if the internal pressure seal body that is always in sliding contact with the guide rod is provided as in patent document 1, friction force is generated between the guide rod and the internal pressure seal body, and therefore energy consumption during movement of the guide rod increases. This makes it difficult to achieve both back pressure cutoff and energy saving.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a sealing device and a sealing structure which can block back pressure and achieve energy saving.

Means for solving the problems

In order to achieve the above object, the sealing device of the present invention is an annular sealing device for sealing between a through hole of a tubular member and a shaft inserted into the through hole, the annular sealing device including: a main lip contacting an outer peripheral surface of the shaft; and a back pressure lip formed on the opposite side of the space to be sealed across the main lip in the axial direction, the back pressure lip extending obliquely so as to be spaced apart from the space to be sealed as it approaches the outer peripheral surface of the shaft, and being formed so as to form a gap between the back pressure lip and the outer peripheral surface of the shaft, a value obtained by dividing a dimension of the back pressure lip in a direction orthogonal to the extending direction by a dimension in the axial direction being 0.9 or less.

The utility model discloses a sealing device that an embodiment relates to still includes: an elastic member having the main lip and the back pressure lip; a reinforcing member integrally formed with the elastic member; and a chucking spring mounted on an outer peripheral side of the main lip.

In order to achieve the above object, the present invention relates to a sealing structure including a through hole of a tubular member, a shaft inserted into the through hole, and an annular sealing device for achieving sealing between the through hole and the shaft, the sealing structure being characterized in that the sealing device is the above sealing device, and a space to be sealed is sealed by contacting at least a main lip of the sealing device with an outer peripheral surface of the shaft.

In the seal structure according to an embodiment of the present invention, a gap between the back pressure lip in a natural state and the outer peripheral surface of the shaft in the seal device is 0.2mm or more and 0.5mm or less.

(effects of the utility model)

According to the utility model relates to a sealing device and seal structure can realize energy-conservingly when blocking the backpressure.

Drawings

Fig. 1 is a sectional view of a seal structure provided with a seal device according to an embodiment of the present invention.

Fig. 2 is a sectional view of a sealing device according to an embodiment of the present invention.

Fig. 3 is a cross-sectional view showing a state where no pressure difference is generated in the sealing device according to the embodiment of the present invention.

Fig. 4 is a cross-sectional view showing a state in which a pressure difference is generated in the sealing device according to the embodiment of the present invention.

Fig. 5 is a cross-sectional view showing a state in which a pressure difference increases in the sealing device according to the embodiment of the present invention.

Fig. 6 is a cross-sectional view showing a state in which the pressure difference is further increased in the sealing device according to the embodiment of the present invention.

Fig. 7 is a graph showing a change with time in the pressure difference in the seal structure provided with the sealing device according to the embodiment of the present invention.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Fig. 1 is a sectional view of a seal structure 10 provided with a seal device 1 according to an embodiment of the present invention, and fig. 2 is a sectional view of the seal device 1. As described below, the sealing device 1 according to the embodiment of the present invention is used for sealing the through hole 101 of the tubular member 100 and the shaft 200, that is, for sealing the space a1 to be sealed formed on one side in the axis x direction with respect to the tubular member 100, as will be described later. The sealing device 1 is provided in, for example, a valve guide system of an intake/exhaust valve of an engine, and a guide rod (shaft) is inserted into a through hole of a valve guide (cylindrical member) to suppress leakage of oil (sealing object) in an oil chamber (sealing object space a 1). Here, the term "seal" is not limited to the case where the object to be sealed does not leak at all, and may be any that allows a predetermined amount of outflow intentionally, and allows the amount of outflow to be controlled when the object flows out.

Hereinafter, for convenience of explanation, the direction of an arrow a (see fig. 1) in the axis x direction (one side in the axis direction) is referred to as an upper side, and the direction of an arrow b (see fig. 1) in the axis x direction (the other side in the axis direction) is referred to as a lower side. In a direction perpendicular to the axis x (hereinafter, also referred to as "radial direction"), a direction away from the axis x (direction of arrow c in fig. 1) is an outer peripheral side, and a direction toward the axis x (direction of arrow d in fig. 1) is an inner peripheral side.

As shown in fig. 1, a sealing device 1 according to an embodiment of the present invention is an annular sealing device for sealing between a through hole 101 of a tubular member 100 and a shaft 200 inserted into the through hole 101, and includes: a main lip 21 that contacts an outer peripheral surface 201 of the shaft 200; and a back pressure lip 22 formed on the opposite side of the space a1 to be sealed with the main lip 21 therebetween in the axis x direction. The back pressure lip 22 extends obliquely so as to be spaced apart from the space to be sealed a1 as it approaches the outer peripheral surface 201 of the shaft 200, and is formed so as to form a gap between the back pressure lip and the outer peripheral surface 201 of the shaft 200, and the value of the dimension T in the direction orthogonal to the extending direction of the back pressure lip divided by the dimension L in the axial direction is 0.9 or less. The sealing device 1 will be specifically described below.

The seal structure 10 provided with the seal device 1 includes a cylindrical member 100 formed with a through hole 101, and a shaft 200 inserted into the through hole 101. The sealing device 1 is airtightly fixed to an outer peripheral surface 102 of the tubular member 100, has a main lip 21 at a portion disposed on an upper side in the x-axis direction with respect to the tubular member 100, and seals between the tubular member 100 and the shaft 200 by contacting an outer peripheral surface 201 of the shaft 200 at the main lip 21. That is, the sealing device 1 suppresses the outflow of the object to be sealed in the space a1 to be sealed on the upper side in the x-axis direction from the gap between the cylindrical member 100 and the shaft 200 to the space a2 on the lower side in the x-axis direction.

The sealing device 1 is formed in a ring shape as a whole, and includes an elastic member 2, a reinforcing member 3, and a garter spring 4.

The elastic member 2 is formed of, for example, rubber, elastic resin, or the like, and includes a1 st cylindrical portion 2A centered on the axis x, and a2 nd cylindrical portion 2B centered on the axis x and having a smaller diameter than the 1 st cylindrical portion 2A, and the 1 st cylindrical portion 2A is connected to a lower end of the 2 nd cylindrical portion 2B in the axis x direction at an upper end in the axis x direction.

The 1 st cylindrical portion 2A is fixed in an airtight manner with its inner peripheral surface in contact with the outer peripheral surface 102 of the cylindrical member 100, and is integrally fixed to the reinforcing member 3 on the outer peripheral surface side. The 1 st cylindrical portion 2A extends to the upper side of the cylindrical member 100 in the axis x direction.

As shown in fig. 2, the 2 nd cylindrical portion 2B is formed with a main lip 21, a back pressure lip 22, and a mounting recess 23. The main lip 21 protrudes toward the inner peripheral side from the upper portion in the axis x direction of the inner peripheral surface of the 2 nd cylindrical portion 2B, and contacts the outer peripheral surface 201 of the shaft 200. The main lip 21 includes a main protrusion 211 that contacts the outer peripheral surface 201, and a plurality of support protrusions 212 that have a smaller protrusion dimension (larger inner diameter) than the main protrusion 211 and are disposed on the lower side in the axis x direction. The support protrusions 212 are arranged equally in the circumferential direction, and serve to improve the following performance of the main lip 21 against eccentricity of the shaft 200 and the like, and to suppress excessive contact (overall contact) of the main lip 21.

The back pressure lip 22 is formed on the inner peripheral surface of the 2 nd cylindrical portion 2B on the lower side in the x direction of the axis line with respect to the main lip 21, and extends toward the lower side in the x direction of the axis line as it goes toward the inner peripheral side. That is, the back pressure lip 22 is formed on the opposite side of the space to be sealed a1 with the main lip 21 therebetween, and extends obliquely so as to be spaced apart from the space to be sealed a1 (i.e., toward the lower side in the axis x direction) as it approaches the outer peripheral surface 201 of the shaft 200 (toward the inner peripheral side). The back pressure lip 22 is formed in the entire circumferential direction, and has a cylindrical shape whose lower side is reduced in diameter in the x direction of the axis as a whole. The dimension (thickness) of the back pressure lip 22 in the direction perpendicular to the extending direction (the direction from the outer peripheral side to the inner peripheral side and from the upper side to the lower side) of the back pressure lip 22 inclined in this manner is T, and the dimension (length) of the back pressure lip 22 in the axis x direction is L. The value obtained by dividing the thickness T by the length L is 0.9 or less (T/L is less than or equal to 0.9).

The mounting recess 23 is a portion formed in a concave shape on the outer peripheral surface side of the 2 nd cylindrical portion 2B, and is used for mounting the chucking spring 4. The mounting recess 23 is formed on the outer peripheral side of the main lip 21, that is, the main lip 21 and the mounting recess 23 are arranged side by side in the radial direction.

The reinforcing member 3 is formed in an annular shape from, for example, a plate-shaped metal member, and integrally includes a cylindrical tubular portion 31 and an annular portion 32, and the annular portion 32 extends from an upper end portion of the tubular portion 31 in the x direction toward the inner peripheral side. The cylindrical portion 31 is fixed to the 1 st cylindrical portion 2A of the elastic member 2, and the annular portion 32 is fixed to the 1 st cylindrical portion 2A and the 2 nd cylindrical portion 2B. By providing the reinforcing member 3, it is possible to suppress the accidental deformation of the elastic member 2.

The chucking spring 4 is formed in an annular shape by, for example, a metal member, and is disposed and attached in the concave attachment recess 23 of the elastic member 2. When the lip 21 elastically contacts the outer peripheral surface 201 of the shaft 200, the garter spring 4 also elastically deforms, and applies an urging force to press the lip 21 against the outer peripheral surface 201.

Hereinafter, the positional relationship of the respective parts in the state where the sealing device 1 is provided in the sealing structure 10 will be described with reference to fig. 3 to 6. First, in a natural state, the inner diameter of the main protrusion 211 of the main lip 21 is smaller than the outer diameter of the outer peripheral surface 201 of the shaft 200, and the main lip 21 is deformed in contact with the outer peripheral surface 201 to contribute to sealing. On the other hand, the inner diameter of the back pressure lip 22 is larger than the outer diameter of the outer peripheral surface of the shaft 200 in the natural state, and the back pressure lip 22 does not contact the outer peripheral surface 201 in a state where no external force acts on the back pressure lip 22.

In the state shown in fig. 3, of the space a2 located below the main lip 21 in the axis x direction, no pressure difference is generated between the upper space a21 located above the back pressure lip 22 and the lower space a22 located below the back pressure lip 22. The back pressure lip 22 is spaced apart from the outer peripheral surface 201, and a gap (radial gap) G1 between the back pressure lip 22 and the outer peripheral surface 201 is set to be 0.2mm to 0.5 mm. At this time, a frictional force of, for example, 2N is generated between the main lip 21 and the outer peripheral surface 201. That is, the frictional force generated between the sealing device 1 and the outer peripheral surface 201 is 2N.

In the state shown in fig. 4, the pressure of the lower space a22 is higher than the pressure of the upper space a21, and the pressure difference is less than 1.5atm, for example. When the pressure in the lower space a22 is higher than that in the upper space a21, a force that causes the back pressure lip 22 to fall toward the upper space a21 acts on the back pressure lip 22, and the front end of the back pressure lip 22 approaches the outer peripheral surface 201. Under this pressure difference, the back pressure lip 22 does not contact the outer peripheral surface 201, and no frictional force is generated between the back pressure lip 22 and the outer peripheral surface 201. Therefore, the frictional force generated between the sealing device 1 and the outer peripheral surface 201 is 2N.

In the state shown in fig. 5, the pressure in the lower space a22 is higher than the pressure in the upper space a21, and the pressure difference is, for example, 1.5atm or more and less than 2 atm. With respect to the state shown in fig. 4, the degree of collapse of the back pressure lip 22 is increased, and the back pressure lip 22 comes into contact with the outer peripheral surface 201 to be in a so-called close-fitting state. At this time, although the back pressure lip 22 contacts the outer peripheral surface 201, the pressing force is sufficiently small, and substantially no frictional force is generated between them. Therefore, the frictional force generated between the sealing device 1 and the outer peripheral surface 201 is substantially 2N.

In the state shown in fig. 6, the pressure in the lower space a22 is higher than the pressure in the upper space a21, and the pressure difference is, for example, 2.5atm or more. With respect to the state shown in fig. 5, the degree of collapse of the back pressure lip 22 is further increased, and the back pressure lip 22 is pressed in contact with the outer peripheral surface 201. At this time, the frictional force generated between the back pressure lip 22 and the outer peripheral surface 201 is, for example, 1N. Therefore, the frictional force generated between the sealing device 1 and the outer peripheral surface 201 becomes 3N.

In the seal structure 10, when the shaft 200 reciprocates, a pressure change as shown in fig. 7 occurs. The horizontal axis of the graph of fig. 7 represents time, and the vertical axis represents the pressure difference between the upper space a21 and the lower space a 22. As time goes by, the pressure difference between the upper space a21 and the lower space a22 sharply increases and decreases, and after the time when the pressure difference is 0 continues, the pressure difference increases and decreases again, and this process is repeated. That is, the back pressure lip 22 is deformed as shown in fig. 3 to 6 in accordance with a change in the pressure difference, and the deformation is repeated.

The following configuration was set as a comparative example: in a natural state, the back pressure lip is brought into contact with the outer peripheral surface 201, and a frictional force of 2N is generated between the back pressure lip and the outer peripheral surface 201. In the present embodiment, energy consumption due to frictional force is reduced by 50% or more in the state shown in fig. 3 to 5, and energy consumption due to frictional force is reduced by 25% or more in the state shown in fig. 6, compared to the comparative example.

In the state shown in fig. 3 and 4, the pressure difference between the upper space a21 and the lower space a22 is relatively small, and therefore the back pressure lip 22 can sufficiently block the back pressure even without contacting the outer peripheral surface 201.

By setting T/L ≦ 0.9 in the back pressure lip 22, the rigidity is not excessively high, and as described above, when a pressure difference is generated between the upper side space a21 and the lower side space a22, the back pressure lip 22 can be easily deformed. Thus, the back pressure lip 22 does not contact the outer peripheral surface 201 when the pressure difference is small, and the back pressure lip 22 is pressed by contacting the outer peripheral surface 201 when the pressure difference is large, thereby easily blocking the back pressure.

On the other hand, if the thickness T of the back pressure lip 22 is too large compared to the axial dimension L, the rigidity of the back pressure lip 22 increases, and therefore, even if a pressure difference occurs between the upper space a21 and the lower space a22, the back pressure lip 22 is less likely to deform, and the back pressure blocking effect is less likely to be obtained.

Since the clearance between the back pressure lip 22 and the outer peripheral surface 201 in the natural state shown in fig. 3 is 0.2mm or more and 0.5mm or less, when the pressure difference between the upper space a21 and the lower space a22 is small, the back pressure lip 22 does not contact the outer peripheral surface 201 and suppresses the frictional force, and when the pressure difference is large, the back pressure lip 22 contacts the outer peripheral surface 201 and is pressed, so that the back pressure is easily blocked.

On the other hand, if the gap between the back pressure lip 22 and the outer peripheral surface 201 in the natural state is too small, the pressure difference between the upper space a21 and the lower space a22 may be small, and a frictional force may be easily generated. Further, if the clearance between the back pressure lip 22 and the outer peripheral surface 201 in the natural state is too large, the back pressure blocking effect may be difficult to obtain when the pressure difference is large.

Thus, according to the sealing device 1 of the embodiment of the present invention, in a natural state, a gap is formed between the back pressure lip 22 and the outer peripheral surface 201 of the shaft 200, and a value obtained by dividing the thickness T of the back pressure lip 22 by the length L is 0.9 or less, so that energy saving can be achieved while blocking back pressure.

Further, since the clearance between the back pressure lip 22 and the outer peripheral surface 201 of the shaft 200 in a natural state is 0.2mm or more and 0.5mm or less, energy saving can be achieved while blocking back pressure.

The present invention is not limited to the above embodiment, and includes other configurations that can achieve the object of the present invention, and the following modifications are also included in the present invention. For example, in the above embodiment, the sealing device 1 includes the reinforcing member 3 and the garter spring 4, but the reinforcing member and the garter spring may be omitted as appropriate depending on the material, size, shape, and the like of the elastic member. That is, when the elastic member is high in rigidity as a whole and is hard to deform, the reinforcing member may be omitted. Further, when the force pressing the main lip against the outer peripheral surface of the shaft is sufficiently large, the garter spring may be omitted.

In the above embodiment, the clearance between the back pressure lip 22 and the outer peripheral surface 201 of the shaft 200 in the natural state is 0.2mm or more and 0.5mm or less, but the clearance may be set appropriately according to the rigidity and size of the back pressure lip 22, and may be smaller than 0.2mm or larger than 0.5 mm. For example, since the value of the thickness T of the back pressure lip 22 divided by the length L becomes small, the back pressure lip 22 becomes low in rigidity and is easily deformed, and thus the clearance between the back pressure lip 22 and the outer peripheral surface 201 of the shaft 200 in a natural state can be increased.

The embodiments of the present invention have been described above, but the present invention is not limited to the sealing device according to the embodiments of the present invention, but includes all embodiments covered by the concept of the present invention and the claims of the present invention. Further, the respective configurations may be appropriately combined to achieve at least part of the above-described problems and effects. For example, the shape, material, arrangement, size, and the like of the components in the above embodiments may be appropriately changed according to a specific use form of the present invention.

Description of the reference numerals

1, sealing the device; 2 an elastic member; 21 a main lip; 211 a main protrusion; 212 support the projection; 22 a back pressure lip; 23 mounting a recess; 2A the 1 st cylindrical part; 2B the 2 nd cylindrical part; 3a reinforcing member; 31 a cylindrical portion; 32 an annular portion; 4, clamping a spring; 10, sealing structure; 100 a cylindrical member; 101 through holes; 102 outer peripheral surface; 200 shafts; 201 outer peripheral surface; a1 sealing the object space; a2 space; a21 upper space; a22 lower space; g1 gap.

Claims (4)

1. A seal device of an annular shape for sealing between a through hole of a cylindrical member and a shaft inserted into the through hole, comprising:

a main lip contacting an outer peripheral surface of the shaft; and

a back pressure lip formed on the opposite side of the space to be sealed with the main lip in the axial direction,

the back pressure lip extends obliquely so as to be spaced apart from the space to be sealed as it approaches the outer peripheral surface of the shaft, and is formed so as to form a gap between the back pressure lip and the outer peripheral surface of the shaft, and a value obtained by dividing a dimension of the back pressure lip in a direction orthogonal to the extending direction by a dimension of the back pressure lip in the axial direction is 0.9 or less.

2. The sealing device of claim 1, comprising:

an elastic member having the main lip and the back pressure lip;

a reinforcing member integrally formed with the elastic member; and

and a chucking spring mounted on an outer peripheral side of the main lip.

3. A seal structure comprising a through hole of a cylindrical member, a shaft inserted into the through hole, and an annular seal means for effecting sealing between the through hole and the shaft, the seal structure being characterized in that,

the seal is according to claim 1 or 2,

at least a main lip of the sealing device is brought into contact with an outer peripheral surface of the shaft, thereby sealing the space to be sealed.

4. The sealing structure of claim 3,

in the sealing device, a clearance between the back pressure lip and the outer peripheral surface of the shaft in a natural state is 0.2mm to 0.5 mm.

Images