JP6336745B2 - Sealing device - Google Patents

Description

  The present invention relates to a sealing device that seals an outer periphery of a rotating body in a car, a general machine, an industrial machine, or the like with a seal lip.

  2. Description of the Related Art Conventionally, as a sealing device in which a protrusion for obtaining a screw seal action is formed on a seal lip, the one illustrated in FIG. 6 is known.

  The sealing device shown in FIG. 6 includes a seal lip 100 formed of a rubber-like elastic material (rubber material or synthetic resin material having rubber-like elasticity), and the lip edge having the smallest diameter is formed on the inner peripheral surface of the seal lip 100. A sealed space side conical surface 102 having a larger diameter on the sealed space (inside the machine) A side and an anti-sealed space side conical surface 103 having a larger diameter on the anti-sealed space (outside the machine) B side are formed with the portion 101 as a boundary. The anti-sealed space-side conical surface 103 is formed with a large number of screw ridges 104 protruding in the shape of a boat bottom. Reference numeral 105 denotes a garter spring for compensating for the tight force of the seal lip 100 against the rotating shaft 200.

  That is, this sealing device is tightly fitted and fixed to the inner peripheral surface of a housing (not shown), and the lip edge portion 101 having the inner diameter of the seal lip 100 is slidably brought into close contact with the outer peripheral surface of the rotary shaft 200 to thereby seal the shaft. The fluid in the sealed space A is prevented from leaking from the shaft periphery to the anti-sealed space B. And since the fluid which tries to leak the sliding part of the sealing lip 100 and the rotating shaft 200 to the anti-sealing space B is pushed back to the sealing space A by the screw sealing action of the screw protrusion 104, it exhibits a good sealing function. (For example, refer to Patent Document 1 below).

JP 2010-60089 A

  However, in this type of sealing device, since the threaded ridge 104 reaches the lip edge portion 101 of the seal lip 100, the lip edge portion 101 with respect to the outer peripheral surface of the rotating shaft 200 is used if the sealing lip 100 has a small pressing force. There is a problem that the contact state of is not stable.

  Specifically, in this type of sealing device, it is necessary to reduce the height of the screw protrusion 104 in order to stabilize the lip line (the contact surface of the lip edge portion 101 with respect to the outer peripheral surface of the rotating shaft 200). When the protrusion 104 is lowered, the screw protrusion 104 does not hit the outer peripheral surface of the rotating shaft 200 on the eccentric escape side due to a slight eccentricity with respect to the rotating shaft 200, and a remarkable screw sealing action cannot be obtained. On the contrary, if the screw ridge 104 is formed high in order to strongly apply the screw ridge 104 to the outer peripheral surface of the rotary shaft 200, the lip edge portion 101 is rotated at the portion intersecting the screw ridge 104 by the pressure contact reaction force. As a result, the lip line breaks off from the outer peripheral surface of the shaft 200. Therefore, when the shaft stops when the screw seal action by the screw protrusion 104 cannot be obtained, the gap leakage occurs. There is likely to occur.

  In particular, since the lip line is smooth in the case of a new product, the lubricating film formed on the lip line due to the intervention of the fluid in the sealed space A during shaft rotation is thin, and the sliding torque is high.

  The present invention has been made in view of the above points, and its technical problem is to provide a sealing device that forms a stable lip line to provide excellent sealing performance and improved lubricity. There is to do.

  As a means for effectively solving the technical problem described above, the sealing device according to claim 1 is a lip edge portion that is slidably in contact with the outer peripheral surface of the rotating body on the inner peripheral surface of the seal lip. And, a sealed space side conical surface having a large diameter from the lip edge portion toward the sealed space side, and an anti-sealed space side conical surface having a large diameter from the lip edge portion toward the anti-sealed space side are formed, A plurality of screw protrusions extending at a predetermined inclination angle with respect to a circumferential direction from a position away from the lip edge portion are formed on the anti-sealing space side conical surface, and the anti-sealing space side conical surface and the anti-sealing space Of the space-side conical surface, only the confined space-side conical surface is formed with a rough surface portion located in a region in contact with the outer peripheral surface of the rotating body.

  A sealing device according to a second aspect of the present invention is the sealing device according to the first aspect, wherein the rough surface portion is formed with a surface roughness of 5 to 40 μm Rzjis by a satin finish.

  According to the sealing device according to the present invention, since the screw protrusion rises from the side opposite to the sealed space from the lip edge portion, it is difficult for the lip edge to lift from the rotating body, and thus a stable lip line is formed, In addition to providing excellent sealing performance, a stable lip line is formed to provide excellent sealing performance, and the rough surface formed on the conical surface of the sealed space forms a thick lubricating film on the lip line. Therefore, the sliding torque can be reduced.

It is a fragmentary sectional view which cuts and shows 1st embodiment of the sealing device which concerns on this invention by the plane which passes along the axial center. It is explanatory drawing which shows the cross-sectional shape and initial stage lip line of the seal lip by 1st embodiment. It is explanatory drawing which shows the screw protrusion and the satin processing part in 1st embodiment. It is a diagram which shows the result of having performed the sliding test about the Example which formed the rough surface part, and the comparative example which does not form a rough surface part, and measuring the torque. It is a fragmentary sectional view which cuts and shows 2nd embodiment of the sealing device which concerns on this invention by the plane which passes along the axial center. It is explanatory drawing which shows the cross-sectional shape of the seal lip of the sealing device by a prior art, and arrangement | positioning of the protrusion in this seal lip.

  Hereinafter, a preferred embodiment of a sealing device according to the present invention will be described with reference to the drawings. 1 to 3 show a first embodiment of a sealing device according to the present invention.

  The sealing device according to the first embodiment is formed of a rubber-like elastic material (rubber material or a synthetic resin material having rubber-like elasticity), and in the mounted state shown in FIGS. In-machine) A seal lip 1 facing the A side and a garter spring 2 that is attached to the outer periphery near the tip of the seal lip 1 and compensates for the pressing force on the outer peripheral surface of the rotary shaft 3 are provided. The rotating shaft 3 corresponds to the rotating body described in claim 1.

  The inner peripheral surface in the vicinity of the tip of the seal lip 1 has a lip edge portion 11 having the smallest diameter, a conical surface 12 on the sealed space side having a large diameter from the lip edge portion 11 toward the sealed space (in-machine) A side, An anti-sealing space side conical surface 13 having a large diameter from the lip edge portion 11 toward the anti-sealing space (outside) B side is formed, that is, the sealing space side conical surface 12 and the anti-sealing space side conical surface opposite to each other. 13, the lip edge portion 11 has a substantially V-shaped cross section.

  On the anti-sealing space side conical surface 13, a number of first screw ridges 14 and second screw ridges extending from the lip edge portion 11 from the anti-sealing space B side at a predetermined inclination angle with respect to the circumferential direction. 15 are alternately formed in the circumferential direction. The first screw ridge 14 and the second screw ridge 15 correspond to the screw ridge described in claim 1, and when the rotary shaft 3 rotates, the rotary shaft 3 is rotated from the sealed space A side. In the direction of causing a screw seal action to push the oil to be sealed that has passed through the sealing sliding portion (lip line L) between the outer peripheral surface and the lip edge portion 11 to the anti-sealing space B side, and to push back to the sealing space A side. It extends so as to form a part.

  The widths of the first screw protrusion 14 and the second screw protrusion 15 and the height of the flange portions 14a and 15a (the height of the protrusion from the anti-sealing space side conical surface 13) are maximized at the intermediate portion in the longitudinal direction. Thus, it is formed in a raised shape that is curved like a keel at the bottom of the boat. The second screw ridge 15 is shorter than the first screw ridge 14, and the end on the sealed space A side of the first screw ridge 14 and the second screw ridge 15 is appropriately formed from the lip edge portion 11. At remote locations and at the same or nearly the same axial position as each other.

The curvature of the flange 15a of the second screw protrusion 15 is larger than the curvature of the flange 14a of the first screw protrusion 14, and a predetermined axial region from the end of the second screw protrusion 15 on the sealed space A side. in X _1, the height of the ridges 15a is higher than the height of the ridges 14a of the first screw projection 14, in the region X ₂ also show anti-sealed space B side from the axial region M, the first screw The height of the flange 14 a of the protrusion 14 is higher than the height of the flange 15 a of the second screw protrusion 15. Specifically, as shown in FIG. 3, the curvature of the rising portion on the lip edge portion 11 side in the flange portion 15 a of the second screw protrusion 15 is the rising edge on the lip edge portion 11 side in the flange portion 14 a of the first screw protrusion 14. The tangential angle of the rising portion on the lip edge portion 11 side of the flange portion 15a of the second threaded protrusion 15 is larger than the curvature of the portion, and the inner peripheral side with respect to the virtual cylindrical surface having the same diameter as the outer peripheral surface of the rotating shaft 3 The tangential angle of the rising portion on the lip edge portion 11 side of the flange portion 14a of the first threaded ridge 14 is an imaginary cylindrical surface having the same diameter as the outer peripheral surface of the rotary shaft 3. On the other hand, an angle β is formed on the outer peripheral side.

The highest part of the ridge portion 15a of the second screw ridge 15 in the axial region X ₁ is in approximately the same radial position as the lip edge portion 11, thus in the initial mounting state, as shown in FIG. 2, A lip line L due to the initial crushing margin of the lip edge portion 11 with respect to the outer peripheral surface of the rotary shaft 3 and a close contact portion M due to the initial crushing margin of the second screw protrusion 15 are formed slightly apart from this lip line L, and the first The flange portion 14a of the one-threaded protrusion 14 is in a non-contact state or a state close to it (a state in which there is almost no crushing allowance) with respect to the outer peripheral surface of the rotating shaft 3. In addition, since the close contact portion M is formed along the flange portion 15a of the second screw protrusion 15, it forms a predetermined inclination angle with respect to the lip line L.

  A rough surface portion 16 is formed in the sealed space side conical surface 12 in a region that can come into contact with the outer peripheral surface of the rotary shaft 3, that is, a region having a predetermined width from the lip edge portion 11. The surface roughness of the rough surface portion 16 is set to 5 to 40 μm Rzjis, preferably 10 to 20 μm Rzjis in terms of 10-point average roughness.

  The sealing device of the first embodiment having the above configuration is fitted to the shaft hole housing of the device so that the seal lip 1 faces the sealed space A side, and the lip edge portion 11 of the seal lip 1 is The oil to be sealed in the sealed space A is prevented from leaking from the shaft periphery to the atmosphere side of the anti-sealed space B by being slidably in contact with the outer peripheral surface of the rotating shaft 3 inserted through the shaft hole housing. To do.

  In this sealing device, in order to reduce sliding torque and sliding heat generation, the pressing force of the seal lip 1 with respect to the rotating shaft 3 is small, so that the crushing margin of the lip edge portion 11 is small. As shown in FIG. 3, in the initial state, the first screw protrusion 14 is substantially non-contact with the outer peripheral surface of the rotating shaft 3, and the second screw The initial crushing allowance is given only to the ridge 15, that is, as shown in FIG. 2, the close contact portion M of the second screw ridge 15 is formed slightly apart from the lip line L, and therefore, the It is possible to effectively prevent the lip line L from becoming discontinuous in the circumferential direction due to the close reaction force of the second screw protrusion 15 and the occurrence of gap leakage to the anti-sealing space B side.

  Further, in the initial state, the first screw ridge 14 is substantially in non-contact with the outer peripheral surface of the rotary shaft 3, but the screw sealing action of the first screw ridge 14 due to the rotation of the rotary shaft 3 is not sufficient. The second screw ridge 15 is provided with an initial crushing margin, and the close contact portion M is formed with a predetermined inclination angle with respect to the lip line L. It functions to compensate for the screw sealing action of the first threaded ridge 14. Therefore, excellent sealing performance can be secured even in the initial state, and sliding torque can be reduced and sliding heat can be reduced.

  On the other hand, of the rough surface portion 16 formed by the matte finish formed on the conical surface 12 on the sealed space side, the portion along the lip edge portion 11 is in contact with the outer peripheral surface of the rotating shaft 3 and constitutes a part of the lip line L. In the lip line L, a thick lubricating oil film is formed by the oil to be sealed intervening from the sealed space A to the rough surface portion 16, and bubbles are generated in the thick lubricating oil film due to minute irregularities of the rough surface portion 16, so that sliding by liquid lubrication occurs. In addition to the torque reducing action, the bubbles cause the action of further reducing the sliding torque. In addition, the screw sealing action caused by the first threaded ridge 14 and the second threaded ridge 15 provided on the anti-sealed space side conical surface 13 causes the lip line L to pass to the anti-sealed space B side. Since the target oil is pushed back to the sealed space A side, this screw sealing action also contributes to the maintenance of a thick lubricating oil film. Therefore, the sliding torque can be remarkably lowered by the cooperation of the rough surface portion 16 of the sealed space side conical surface 12 and the first screw protrusion 14 and the second screw protrusion 15 of the anti-sealed space side conical surface 13. Even if the sealing device is new, the sliding torque during the initial rotation of the rotating shaft 3 can be effectively reduced.

  Note that the rough surface portion 16 formed by the matte finish formed on the conical surface 12 on the sealed space side has a minute unevenness of 5 to 40 μm, preferably about 10 to 20 μm, and thus constitutes a part of the lip line L. In the portion, the minute unevenness is crushed due to contact with the outer peripheral surface of the rotating shaft 3, and the lip line L is interrupted because the rough surface portion 16 is not formed in the portion near the conical surface 13 on the anti-sealing space side of the lip line L. There is no.

  In addition, when the rough surface portion 16 is formed on the anti-sealed space side conical surface 13 by the satin finish processing, the lubricating oil film forming action thereby reverses the screw sealing action by the first screw protrusion 14 and the second screw protrusion 15. It is not preferable because it interferes. Therefore, in this invention, the rough surface part 16 is formed in the sealed space side conical surface 12.

  When the lip edge portion 11 is gradually worn by sliding with the outer peripheral surface of the rotary shaft 3 and the width of the lip line L is increased, the second screw protrusion 15 is also brought into close contact with the wear. The length and area of the portion M increase, and the first threaded ridge 14 is in close contact with the outer peripheral surface of the rotating shaft 3 at the end on the sealed space A side. Since it also increases over time, a remarkable screw sealing action is also induced in the first threaded ridge 14 and excellent sealing performance is maintained.

  FIG. 4 shows an embodiment in which a rough surface portion having a roughness of 10 μm Rzjis is formed along the lip edge portion on the conical surface on the sealed space side, an embodiment in which a rough surface portion having a roughness of 20 μm Rzjis is formed, and a rough surface portion is not formed. About a comparative example, the sliding test of two test samples is performed, respectively, and the result of having measured the torque is shown. From this test result, it can be seen that in each of the examples in which the rough surface portions having a roughness of 10 μm Rzjis and 20 μm Rzjis were formed, the torque was reduced by about 30% compared to the comparative example.

  Next, FIG. 5 shows a second embodiment of the sealing device according to the present invention. In this embodiment, the difference from the first embodiment described above is that only one type of screw protrusion 17 is formed on the anti-sealed space side conical surface 13.

  Specifically, the threaded ridge 17 formed on the anti-sealing space-side conical surface 13 has a bottom shape that gradually changes so that the height of the protrusion from the anti-sealing space-side conical surface 13 is the highest in the middle in the longitudinal direction. The tip portion 17a facing the lip edge portion 11 side has a shape that is cut out so as to rapidly reduce the width and height. Specifically, the tip 17a of each screw ridge 17 rises from the anti-sealing space side conical surface 17 at a position away from the lip edge portion 11 toward the anti-sealing space B, and the ridge 17b of the screw ridge 17 is From the top of the tip 17a toward the anti-sealing space B, the bottom of the boat 17 is curved in a keel shape, and the top of the tip 17a of each screw ridge 17 has a slightly smaller inner diameter than the lip edge 11. Protrudes to the side.

  On the other hand, in the sealed space side conical surface 12, the rough surface portion 16 by the satin finish processing is provided in a region that can come into contact with the outer peripheral surface of the rotating shaft 3, that is, a region having a predetermined width from the lip edge portion 11. Is formed.

  Therefore, also in the second embodiment, the tip 17a of the screw ridge 17 is brought into close contact with the rotary shaft 3 at a position away from the close region of the lip edge portion 11 with respect to the rotary shaft 3, and therefore the screw ridge 17 Therefore, it is possible to effectively prevent the lip edge portion 11 from being lifted from the outer peripheral surface of the rotary shaft 3 to cause gap leakage, and the screw of the rough surface portion 16 of the sealed space side conical surface 12 and the anti-sealed space side conical surface 13. By cooperating with the ridge 17, the sliding torque can be significantly reduced.

DESCRIPTION OF SYMBOLS 1 Seal lip 11 Lip edge part 12 Sealing space side conical surface 13 Anti-sealing space side conical surface 14 1st thread protrusion (screw protrusion)
15 Second screw protrusion (screw protrusion)
16 Rough surface 17 Threaded ridge 3 Rotating shaft (Rotating body)
A Sealed space B Anti-sealed space

Claims (2)

  A lip edge portion slidably in contact with the outer peripheral surface of the rotating body on the inner peripheral surface of the seal lip, a sealed space side conical surface having a large diameter from the lip edge portion toward the sealed space side, and the lip An anti-sealing space-side conical surface having a large diameter from the edge portion toward the anti-sealing space side is formed, and a predetermined direction with respect to a circumferential direction from a position away from the lip edge portion is formed on the anti-sealing space-side conical surface. A number of threaded ridges extending at an angle of inclination are formed, and only the sealed space-side conical surface of the sealed space-side conical surface and the anti-sealed space-side conical surface can contact the outer peripheral surface of the rotating body. A sealing device characterized in that a rough surface portion is formed at a position.   The sealing device according to claim 1, wherein the rough surface portion is formed with a surface roughness of 5 to 40 μm Rzjis by a satin finish.

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