JP2003090439A - Sealing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealing device fully exerting a pumping function in an initial condition while improving the sealing performance. SOLUTION: This sealing device is provided with a surface contact part 9c contacting a rotational shaft 20 with surface to surface in the initial condition after installed between a housing 10 and the rotational shaft 20 at a connection area of continuously provided parallel thread projections 9d and concave thread projections 9.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealing device such as an oil seal used for a shaft sealing portion of various devices.
The present invention relates to a lip having a thread protrusion on an inclined surface on the atmosphere side at the tip end. 2. Description of the Related Art As a conventional sealing device of this kind, for example, the one shown in FIG. 3 is known (for example, FIG. 3).
See JP-A-9-42463). FIG. 3 is a schematic view showing a conventional sealing device 100. FIG. 3A is a longitudinal sectional view of a seal lip portion, and FIG. 3B is a longitudinal sectional view of a main part. [0004] That is, the sealing device 100 seals an annular gap between a housing 101 as two members concentrically and rotatably assembled with each other and a rotary shaft 102 inserted into the housing 101. An annular seal body 103 fitted on the inner periphery of the housing 101;
And a sealing lip 105 that extends in a direction and the lip tip 104 slidably and sealingly contacts the rotating shaft 102. [0005] The lip tip 104 has a mountain-shaped cross-section, and has an inclined surface 107 to be sealed which is gradually inclined from the top 106 toward the sealed side O in the axial direction so as to have a smaller diameter.
6 has an atmosphere-side inclined surface 108 inclined so as to gradually decrease in diameter toward the atmosphere-side atmospheric side A, and a plurality of thread projections 109 linearly formed on the atmosphere-side inclined surface 108 in the circumferential direction. Was provided. [0006] Such a sealing device with a screw projection is as follows.
With respect to leakage due to initial failure (shaft damage, lip damage, etc.), the conventional oil suction performance has been improved and developed for the purpose of preventing oil leakage by improving the oil suction performance. [0007] In the screw projection 109,
The protrusion height is gradually increased from the sealing target side end portion 109a toward the atmosphere side A so that the maximum height is located at the atmosphere side end portion 109b. The remaining portions of the screw projections 109 are brought into contact with each other to provide a screw pump effect, thereby improving sealing performance. [0008] However, in the case of the above-described prior art, the following problems may occur. FIG. 4A shows the sealing device 100 shown in FIG.
FIGS. 4B and 4C are views for explaining the screw protrusion 109 of FIG. 3A, and FIG. 4B is a sectional view taken along line aa of the screw protrusion 109 shown in FIG. B of the projection 109
It is -b sectional drawing. [0010] As shown in the figure, since the top of the screw projection 109 is formed at an acute angle toward the tip, a contact surface with the rotating shaft 102 cannot be made wide in an initial state. There is a possibility that the pump function cannot be sufficiently exerted. SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide a sealing device in which a pump function is sufficiently exhibited in an initial state to improve sealing performance. To provide. According to the present invention, there is provided a sealing device for sealing an annular gap between two members which are concentrically and relatively rotatably assembled with each other. An annular seal body attached to one of the two members, and provided on the seal body;
A seal lip slidably and sealingly contacting the other of the two members, the seal lip having a width and a protruding height substantially equal to each other on a peripheral surface of the seal lip on the side to be sealed. A first screw protrusion, and the first screw protrusion is provided on the non-sealing target side opposite to the first screw protrusion, and at least the protruding height of the protruding height and the width is directed toward the non-sealing target side. A plurality of second screw protrusions that gradually increase in size in the initial state provided between the two members in a connection region of the first and second screw protrusions provided continuously. It is characterized by including a surface contact portion that makes surface contact with the other member. [0013] With this, in the initial state in which the sealing device is incorporated between the two members, the first provided continuously.
In addition, since the connection region of the second screw protrusion can be brought into surface contact with the other member, the contact surface with the other member can be widened, and the pump function can be sufficiently exhibited. Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the dimensions of the components described in this embodiment,
The material, shape, and relative arrangement thereof should be appropriately changed depending on the configuration of the apparatus to which the invention is applied and various conditions, and are not intended to limit the scope of the invention to the following embodiments. FIG. 1 is a schematic view showing a sealing device 1 according to an embodiment of the present invention. FIG. 1A is a longitudinal sectional view of a seal lip portion, and FIG. (C) is a schematic view showing the parallel screw projection 9d and the boat bottom screw projection 9, and (d) is a cross-sectional view along the ridge line of the parallel screw projection 9d and the boat bottom screw projection 9, and FIG. Is a sectional view taken along line aa of the parallel screw protrusion 9d shown in FIG. 4C, FIG. 4F is a sectional view taken along line bb of the surface contact portion 9c shown in FIG. 4C, and FIG. It is cc sectional drawing of the near end 9b of the anti-sealing object side of the bottom screw protrusion 9 shown in FIG. The sealing device 1 according to the present embodiment has an annular clearance between a housing 10 as two members which are concentrically and relatively rotatably assembled with each other and a rotating shaft 20 inserted into the housing 10. Is to be sealed. The sealing device 1 generally has an annular seal body 2 fitted on the inner periphery of a housing 10 and a lip tip extending from the seal body 2 to the side O to be sealed such as oil, water, chemicals, and air. A seal lip 3 made of a rubber-like elastic material is slidably and sealingly contacted with the rotary shaft 20, and a seal lip 3 extends from the seal body 2 to the atmosphere side A, which is the side to be sealed, and the lip tip slides on the rotary shaft 20. And a dust lip 5 made of a rubber-like elastic material that is in movably sealing contact. The seal body 2 is a metal ring 2 having an L-shaped cross section.
a and a rubber-like elastic body 2b formed integrally with the metal ring 2a. The metal ring 2a includes a cylindrical portion 2c and a cylindrical portion 2c.
And an inward flange portion 2d extending radially inward from the end A on the atmosphere side. The cylindrical portion 2c of the metal ring 2a and the rubber-like elastic body 2b integrally formed on the outer periphery of the cylindrical portion 2c constitute a fitting portion fitted on the inner periphery of the housing 10. ing. The seal lip 3 extends from the inner diameter end of the inward flange portion 2d of the metal ring 2a to the side O to be sealed in the axial direction, and the lip tip portion 4 slidably and sealingly contacts the rotary shaft 20. . The inner peripheral shape of the lip tip portion 4 of the seal lip 3 has a mountain-shaped cross section projecting radially inward, and gradually decreases in diameter from the top portion 6 serving as a sliding surface toward the atmosphere side A in the axial direction. Atmospheric side inclined surface 8 as peripheral surface inclined to become
And a sealing target side inclined surface 7 that is inclined from the top 6 toward the sealing target side O in the axial direction so as to gradually decrease in diameter. The dust lip 5 extends from the inner diameter end of the inward flange portion 2d of the metal ring 2a so as to gradually decrease in diameter toward the atmosphere side A in the axial direction. Slidably and sealingly. A spring member 11 such as a garter spring is attached to the outer periphery of the lip tip 4 of the seal lip 3 to apply a tightening force to the seal portion of the lip tip 4. Hereinafter, a screw projection, which is a characteristic configuration of the present embodiment, will be described with reference to FIGS. 1 (c) to 1 (g). A parallel screw protrusion 9d as a first screw protrusion and a parallel screw protrusion 9d at the atmosphere side A of the parallel screw protrusion 9d are continuously formed on the atmosphere-side inclined surface 8 on the inner periphery of the lip tip portion 4 of the seal lip 3. And a plurality of boat bottom screw protrusions 9 as second screw protrusions provided at predetermined intervals along the circumferential direction. The parallel screw projection 9d is provided substantially linearly over a predetermined dimension from the top 6 of the lip tip 4 to the atmosphere side A, and has the same width and height in the length direction. The bottom screw projection 9 is provided so as to extend linearly from the sealing target side O toward the atmosphere side A continuously from the parallel screw projection 9d, and is provided with the parallel screw projection 9d and the bottom screw projection. Reference numeral 9 is inclined at a predetermined angle in the same direction with respect to a line of intersection between the atmosphere-side inclined surface 8 and a plane passing through the central axis (corresponding to the generatrix of the cone constituting the atmosphere-side inclined surface 8). Further, as shown in the figure, the boat bottom screw projection 9 has a projecting height gradually increasing from the sealing target side end 9a toward the atmosphere side A. The end 9b has a maximum height. In the bottom screw projection 9, the cross-sectional shape orthogonal to the longitudinal direction of the bottom screw projection 9 is such that, in the region on the atmosphere side A, a ridge line in which the top portion, which is the tip of the screw projection, is continuously continuous is formed. The cross section to be formed is approximately triangular (bottom shape, Fig. 1
(G)), in the region B on the side O to be sealed shown in FIGS. 1C and 1D, the cross section is substantially triangular in shape, which forms a ridge line whose top is continuously connected to the region on the atmosphere side A. The cross section is formed in a substantially trapezoidal shape (FIG. 1 (f)) so as to have a substantially planar shape with a cut top. Here, the boat bottom screw protrusion 9
In the region B of the sealing target side O (at least the region including the connection region of the continuously provided parallel screw projections 9d and the bottom screw projections 9), the sealing device 1 has a housing 10 which is substantially flat. , And a surface contact portion 9 c that comes into surface contact with the rotating shaft 20 in an initial state incorporated between the rotating shafts 20. The angle of the apex (the apex in the region B when assumed to be substantially triangular in cross section) is the same angle over the entire length of the ridge, and the left and right inclined surfaces with respect to the ridge are the same as the air-side inclined surface 8 of the lip tip 4. The width of the intersecting portion is a boat bottom shape that gradually increases from the sealing target side end portion 9a toward the atmosphere side A. In the present embodiment, the atmosphere side end portion 9b is the maximum width. In the sealing device 1 having the above-described structure, in the initial state in which the sealing device 1 is installed between the housing 10 and the rotary shaft 20, the top 6 of the lip tip portion 4 is in close contact with the entire circumference and the sealing is performed. At the same time as forming the part, the parallel screw protrusion 9d and the surface contact part 9c come into contact with each other to exhibit a screw pump function. In the prior art, the top of the screw projection was formed at an acute angle toward the tip, so that in the initial state, the contact surface could not be widened and the pump function could not be sufficiently exhibited. By providing the surface contact portion 9c as in the present embodiment, it is possible to widen the contact surface with the rotating shaft 20 in the initial state, so that the pump function can be sufficiently exhibited. Oil suction performance can be improved. Further, the projecting height of the boat bottom screw projection 9 gradually increases from the end 9a on the side to be sealed toward the atmosphere side A, so that even if the abrasion of the seal portion progresses, the rotating shaft 20 is not rotated. , A good contact state can be maintained. Therefore, in the sealing device 1, it is possible to reliably prevent oil leakage. Here, the surface contact portion 9c only needs to be in surface contact with the rotating shaft 20 in the initial state in which the sealing device 1 is installed between the housing 10 and the rotating shaft 20, and a parallel screw provided continuously is provided. A region where the surface contact portion 9c is provided in the connection region between the protrusion 9d and the bottom screw protrusion 9 (for example,
The length direction of the boat bottom screw projection 9 and the projection height direction of the projection) may be appropriately set in accordance with the material, the use condition, and the like. By appropriately setting the surface contact portion, the pump amount can be controlled, and the degree of freedom in designing the screw protrusion can be improved. In the present embodiment, the parallel screw projection 9
d is substantially triangular in cross section as in the conventional shape (FIG. 1 (e)).
However, as shown in FIG. 2, the surface contact portion which is a characteristic configuration of the present embodiment includes a parallel screw protrusion 9 d and a parallel screw It may be provided over the protrusion 9d, or may be provided over both the boat bottom screw protrusion 9 and the parallel screw protrusion 9d. In the present embodiment, as shown in FIG. 1, the screw projection is a boat bottom screw projection 9 having a boat bottom shape that is gently curved and the height is increased. It may be a so-called tapered screw protrusion having a higher height. In this embodiment, the so-called inner seal in which the seal body 2 is fixed to the housing 10 and the seal lip 3 is in sealing contact with the rotary shaft 20 has been described. However, the seal body is fixed to the rotary shaft and the seal lip is The present invention can also be applied to a so-called outer seal that comes into sealing contact with the inner periphery. As described above, according to the present invention,
Since the surface contact portion provided in the connection region of the first and second screw protrusions provided continuously can be brought into surface contact with the other member in an initial state of being assembled between the two members,
The contact surface with the other member can be widened, and the pump function can be sufficiently exhibited. Therefore, the oil suction performance can be improved, and oil leakage can be reliably prevented, so that the sealing performance can be improved. Also, by appropriately setting the surface contact portion, the pump amount can be controlled, and the degree of freedom in designing the screw protrusion can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view showing a sealing device according to an embodiment of the present invention, wherein FIG. 1 (a) is a longitudinal sectional view of a seal lip portion, and FIG. FIG. 4C is a schematic view showing a parallel screw protrusion and a bottom screw protrusion, FIG. 4D is a cross-sectional view along a ridge line of the parallel screw protrusion and the bottom screw protrusion, and FIG. (C) is a sectional view taken along aa, (f) is a sectional view taken along the line bb in (c), and (g) is a sectional view taken along the line cc in FIG. FIG. 2A is a schematic view showing a parallel screw projection provided with a surface contact portion, and FIG. 2B is a cross-sectional view taken along the line aa of FIG. FIG. 3 is a schematic view showing a conventional sealing device. FIG. 3 (a) is a longitudinal sectional view of a seal lip portion, and FIG. 3 (b) is a longitudinal sectional view of a main part. FIG. 4A is a view for explaining a conventional screw protrusion, and FIG. 4B is a sectional view taken along a line aa of FIG.
FIG. 3C is a sectional view taken along line bb of FIG. [Description of Signs] 1 Sealing device 2 Seal body 2a Metal ring 2b Rubber-like elastic body 2c Cylindrical portion 2d Inward flange portion 3 Seal lip 4 Lip tip 5 Dustrip 6 Top 7 Sealing target side inclined surface 8 Atmospheric side inclined surface 9 Boat bottom screw protrusion 9a Sealed end 9b Atmospheric end 9c Surface contact 9d Parallel screw protrusion 10 Housing 11 Spring member 20 Rotation axis O Sealed side A Atmospheric side

Claims (1)

Claims: 1. A sealing device for sealing an annular gap between two members which are concentrically and relatively rotatably assembled with each other, wherein the annular member is attached to one of the two members. And a seal lip provided on the seal body and slidably and sealingly in contact with the other of the two members. And a first screw protrusion having substantially the same height as the first screw protrusion;
A second screw, which is provided continuously to the first screw protrusion on the non-sealing target side of the screw protrusion, and at least the protruding height of the protruding height and width gradually increases toward the non-sealing target side And a plurality of projections, wherein a surface contact is made in a connection area between the first and second screw projections provided continuously and in surface contact with the other member in an initial state provided between the two members. A sealing device comprising a part.