JP2010084819A - Sealing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce torque based on fluid lubrication by increasing the thickness of a fluid film in a lip sliding part, in a sealing device (bidirectional seal) in which a sliding mate member such as a rotary shaft is rotated in a normal direction and a reverse direction. <P>SOLUTION: A normal screw part 10 and a reverse screw part 11 for pumping are provided in an inclined surface of a seal lip 6 on a side opposite to a sealed fluid side. A recessed part 12 is provided in an intermediate surface 9 of the seal lip 6, and a contact part 15 continued on the circumference is provided in a part of the recessed part 12 of the intermediate surface 9 on a side opposite to the sealed fluid side. When a mate member among the edges of the recessed part 12 is normally rotated, at least one part of a part positioning in front in the rotating direction is set in a direction inclined forward in the rotating direction at this point from a sealed fluid side to the side opposite to the sealed fluid. When the mate member among the edges of the recessed part 12 is rotated reversely, at least one part of the part positioning in front in the rotating direction is set in a direction inclined forward in the rotating direction at this point from the sealed fluid side to the side opposite to the sealed fluid side. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a sealing device, and more particularly to a sealing device having a sealing lip. The sealing device of the present invention is used, for example, in the field of automobiles or in the field of general-purpose machines.

  Generally, a sealing device having a seal lip is required to have a low torque so as to suppress sliding wear of the seal lip. As methods for reducing torque, reduction of the frictional force, such as reducing the tension by reducing the cross-section of the seal lip, changing the material, and modifying the surface (for example, fluororesin coating) has been studied. In order to realize a reduction in torque, it is conceivable to realize a reduction in torque based on fluid lubrication by increasing the thickness of the fluid film (oil film) in the sliding portion.

  Moreover, as a sealing device having a seal lip, conventionally, a sliding partner such as a rotating shaft rotates in only one direction (one-way rotating seal), and a device that rotates in both forward and reverse directions (two-way rotating seal) Therefore, not only the former one-way rotating seal but also the latter two-way rotating seal is required to reduce the torque based on the fluid lubrication.

As shown in FIG. 10, as a prior art of the bi-directional rotating seal, the sealing fluid is pumped to the anti-sealing fluid side inclined surface 52 of the seal lip 51 so as to improve the sealing performance by the pumping action when the mating member 53 rotates in the forward direction. There is known one provided with a normal screw portion 54 that exerts an action of pushing back and a reverse screw portion 55 that exerts an action of pushing back the sealing fluid by a pumping action when the counterpart member 53 rotates in the reverse direction. However, torque reduction based on the fluid lubrication is not realized (see Patent Document 1).
Japanese Unexamined Patent Publication No. 1-312274 JP 2003-185028 A JP 2006-125454 A

  In view of the above, the present invention provides a sealing device (bidirectional seal) in which a sliding counterpart member such as a rotating shaft rotates in both forward and reverse directions by increasing the thickness of the fluid film in the lip sliding portion as described above. The purpose is to achieve low torque based on lubrication.

  In order to achieve the above object, a sealing device according to claim 1 of the present invention is a sealing device in which a mating member such as a rotating shaft rotates relative to both forward and reverse directions, and is slidably in close contact with the peripheral surface of the mating member. The sealing lip has a sealing fluid side slope and an anti-sealing fluid side slope and an intermediate surface provided between the both slopes, and is pumped when the mating member rotates in the forward direction. A positive screw portion that exerts an action of pushing back the sealing fluid by an action, and a reverse screw portion that exerts an action of pushing back the sealing fluid by a pumping action when the counterpart member rotates in the reverse direction, are provided on the anti-sealing fluid side inclined surface, A concave portion is provided on the intermediate surface, and the concave portion is provided so as not to reach a boundary portion between the intermediate surface and the anti-sealing fluid side slope, and is provided at a portion of the intermediate surface on the anti-sealing fluid side. A contact portion for the circumferentially continuous member is provided, and at least a part of the edge of the recess that is forward in the rotational direction when the partner member rotates in the forward direction is anti-sealed from the sealed fluid side. It is set to the direction which inclines forward of the rotation direction at this time toward the fluid side, and at least a part of the portion which is the front of the rotation direction when the counterpart member rotates in the reverse direction among the edges of the recesses It is characterized in that it is set to be inclined in the forward direction of the rotation direction from the sealing fluid side to the anti-sealing fluid side.

  The sealing device according to claim 2 of the present invention is a sealing device in which a mating member such as a rotating shaft relatively rotates in both forward and reverse directions, and has a seal lip that is slidably in contact with the peripheral surface of the mating member. The sealing lip has a sealing fluid side inclined surface and an anti-sealing fluid side inclined surface and an intermediate surface provided between the both inclined surfaces, and when the counterpart member rotates in the forward direction, the sealing fluid is pumped by a pumping action. A forward screw portion that exerts an action of pushing back and a reverse screw portion that acts to push back the sealing fluid by a pumping action when the counterpart member rotates in the reverse direction are provided on the inclined surface on the anti-sealing fluid side, and a recess is formed in the intermediate surface The concave portion is provided so as not to reach a boundary portion between the intermediate surface and the anti-sealing fluid side inclined surface, and is continuous on the circumference to a portion of the intermediate surface on the anti-sealing fluid side of the concave portion. A contact portion for the hand member is provided, and at least a part of the bottom surface of the recess that is forward in the rotation direction when the counterpart member rotates in the forward direction is deeper toward the front in the rotation direction at this time. The portion of the edge of the recess that is forward in the rotational direction when the mating member rotates in the reverse direction is at least part of the front in the rotational direction at this time. It is characterized by being set to an inclined surface shape in which the depth gradually decreases toward.

  In the sealing device according to claim 1 of the present invention having the above-described configuration, an intermediate surface is provided between the sealing fluid-side inclined surface and the anti-sealing fluid-side inclined surface of the seal lip, a concave portion is provided in the intermediate surface, and the concave portion is the intermediate surface. In addition, a contact portion is provided so as not to reach the boundary portion of the anti-sealing fluid-side inclined surface, and a contact portion with respect to the opposite member that is circumferentially continuous at a portion of the intermediate surface on the anti-sealing fluid side of the recess.

  Further, at least a part of the edge of the recess that is forward in the rotational direction when the counterpart member rotates in the forward direction is inclined forward in the rotational direction from the sealed fluid side to the anti-sealed fluid side. The orientation is set. Accordingly, when the mating member rotates in the forward direction, a part of the sealing fluid introduced into the sliding portion of the seal lip, that is, the sealing fluid introduced into the intermediate surface of the seal lip, is taken into the recess, and the taken-in sealing fluid Is dragged by the rotation of the mating member, flows and converges along the inclination of the edge of the recess, overflows from the recess to the intermediate surface in such a focused state, and forms a thick fluid film on the intermediate surface. As the pressure, a dynamic pressure that floats the intermediate surface from the counterpart member is generated.

  Further, at least a part of the edge of the recess that is forward in the rotational direction when the counterpart member rotates in the reverse direction is inclined forward from the sealed fluid side to the anti-sealed fluid side. The orientation is set. Therefore, when the mating member rotates in the reverse direction, a part of the sealing fluid introduced into the sliding portion of the seal lip, that is, the sealing fluid introduced into the intermediate surface of the seal lip, is taken into the recess, and the taken-in sealing fluid Is dragged by the rotation of the mating member, flows and converges along the inclination of the edge of the recess, overflows from the recess to the intermediate surface in such a focused state, and forms a thick fluid film on the intermediate surface. As the pressure, a dynamic pressure that floats the intermediate surface from the counterpart member is generated.

  Therefore, as described above, even when the mating member rotates in the forward direction or in the reverse direction, a thick fluid film is formed on the intermediate surface and dynamic pressure is generated. Therefore, in any case, the torque can be reduced based on fluid lubrication. Is realized.

  Since the contact portion provided on the intermediate surface is continuous on the circumference, there is also an action of suppressing so-called stationary leakage.

  In the sealing device according to claim 2 of the present invention having the above-described configuration, an intermediate surface is provided between the sealing fluid side inclined surface and the anti-sealing fluid side inclined surface of the seal lip, a concave portion is provided in the intermediate surface, and the concave portion is the intermediate surface. In addition, a contact portion is provided so as not to reach the boundary portion of the anti-sealing fluid-side inclined surface, and a contact portion with respect to the opposite member that is circumferentially continuous at a portion of the intermediate surface on the anti-sealing fluid side of the concave portion.

  Further, at least a part of the bottom surface of the concave portion that is forward in the rotational direction when the counterpart member rotates in the forward direction is an inclined surface whose depth gradually decreases toward the forward in the rotational direction at this time. Is set to Accordingly, when the mating member rotates in the forward direction, a part of the sealing fluid introduced into the sliding portion of the seal lip, that is, the sealing fluid introduced into the intermediate surface of the seal lip, is taken into the recess, and the taken-in sealing fluid Is dragged by the rotation of the mating member, flows and converges along the slope of the bottom surface of the recess, overflows from the recess to the intermediate surface in such a focused state, and forms a thick fluid film on the intermediate surface. As the pressure, a dynamic pressure that floats the intermediate surface from the counterpart member is generated.

  Further, at least a part of the bottom surface of the concave portion that is forward in the rotation direction when the counterpart member rotates in the reverse direction is inclined so that the depth gradually decreases toward the front in the rotation direction at this time. Is set to Therefore, when the mating member rotates in the reverse direction, a part of the sealing fluid introduced into the sliding portion of the seal lip, that is, the sealing fluid introduced into the intermediate surface of the seal lip, is taken into the recess, and the taken-in sealing fluid Is dragged by the rotation of the mating member, flows and converges along the slope of the bottom surface of the recess, overflows from the recess to the intermediate surface in such a focused state, and forms a thick fluid film on the intermediate surface. As the pressure, a dynamic pressure that floats the intermediate surface from the counterpart member is generated.

  Therefore, as described above, even when the mating member rotates in the forward direction or in the reverse direction, a thick fluid film is formed on the intermediate surface and dynamic pressure is generated. Therefore, in any case, the torque can be reduced based on fluid lubrication. Is realized.

  Further, since the contact portion provided on the intermediate surface is continuous on the circumference, there is also an action of suppressing so-called stationary leakage.

  The present invention has the following effects.

  That is, in the sealing device according to claim 1 of the present invention, as described above, the portion of the edge of the recess that is forward in the rotational direction when the counterpart member rotates in the forward direction is from the sealed fluid side to the anti-sealed fluid side. Therefore, when the counterpart member rotates in the forward direction, a thick fluid film is formed on the intermediate surface by the sealing fluid that is taken in and converged when the counterpart member rotates in the forward direction. Will occur. In addition, the part of the edge of the recess that is forward in the rotational direction when the counterpart member rotates in the opposite direction is set to be inclined in the forward direction in the rotational direction from the sealed fluid side to the anti-sealed fluid side. Therefore, when the mating member rotates in the reverse direction, a thick fluid film is formed on the intermediate surface by the sealing fluid that is taken in and converged in the recess, and dynamic pressure is generated. Therefore, even when the mating member rotates in the forward direction or in the reverse direction, a thick fluid film is formed on the intermediate surface and dynamic pressure is generated. Therefore, in any case, it is possible to realize a low torque based on fluid lubrication. it can. The circumferentially continuous contact portion can suppress so-called stationary leakage.

  Moreover, in the sealing device according to claim 2 of the present invention, as described above, the portion of the bottom surface of the recess that is forward in the rotational direction when the counterpart member rotates in the forward direction is directed forward in the rotational direction at this time. As the mating member rotates in the forward direction, a thick fluid film is formed on the intermediate surface by the sealed fluid that is taken in and converged in the concavity and generates dynamic pressure. To do. Moreover, since the part which becomes the front of a rotation direction when the other member rotates in a reverse direction among the bottom surfaces of a recessed part is set to the inclined surface shape where load becomes shallow gradually toward the front of the rotation direction at this time When the mating member rotates in the reverse direction, a thick fluid film is formed on the intermediate surface by the sealing fluid that is taken in and converged in the recess, and dynamic pressure is generated. Therefore, even when the mating member rotates in the forward direction or in the reverse direction, a thick fluid film is formed on the intermediate surface and dynamic pressure is generated. Therefore, in any case, it is possible to realize a low torque based on fluid lubrication. it can. The circumferentially continuous contact portion can suppress so-called stationary leakage.

  The present invention includes the following embodiments.

Claim 1 related ...
(1) The present invention is an improved invention of an oil seal having a flat portion (intermediate surface) inclined on the oil side and a suction reverse screw provided from the oil side, and is applied to both rotary seals. Is.
(2) A concave portion is provided on the intermediate surface so as to reach the boundary between the intermediate surface and the sealed fluid side inclined surface, and not to reach the boundary between the intermediate surface and the anti-sealed fluid side inclined surface. A continuous contact portion is secured.
(3) The boundary between the recess and the intermediate surface in the sliding direction (rotation direction) and the boundary surface (the recess edge) are orthogonal to the sliding direction or forward from the sealing fluid side to the anti-sealing fluid side. Set to tilt direction.
(4) Since the concave portion corresponds to both rotations, a shape that is line-symmetric in the axial direction is desirable, but the inclination angles on both sides in the circumferential direction of the concave portion may be different.
(5) The boundary line between the concave portion in the front of the sliding direction and the intermediate surface may be a curved shape, and is set so that a part thereof is inclined forward in the sliding direction from the sealing fluid side to the anti-sealing fluid side. .
(6) With this configuration, the lubricating oil taken into the recess is drawn in the shaft sliding direction by the rotation of the shaft, and further fed to the anti-sealing fluid side by the shape of the recess.
(7) The lubricating oil that has reached the anti-sealing fluid side inclined surface is returned to the sealing fluid side by the anti-sealing fluid side inclined screw.
(8) Thereby, the pressure which floats an intermediate surface is generated, and the oil film thickness of the intermediate surface is increased, thereby realizing a reduction in torque based on fluid lubrication.
(9) By providing a recess as shown in the following embodiment, the effects (6), (7), and (8) can be applied to both rotations.

Claim 2 related ...
(10) The present invention is an improved invention of an oil seal having a flat part (intermediate surface) inclined on the oil side and a suction reverse screw provided from the oil side, and is applied to both rotary seals. Is.
(11) A concave portion having an inclined surface whose depth gradually decreases in both rotation directions of the shaft is provided on the intermediate surface.
(12) The recess communicates with the sealed fluid side slope, but does not communicate with the anti-sealed fluid side slope. A continuous contact portion is secured on the anti-sealing fluid side of the intermediate surface.
(13) The recess may have a bottom surface other than the inclined surface.
(14) Moreover, you may provide the recessed part symmetrical to an axial direction alternately.
(15) The boundary line (concave edge) between the inclined surface and the intermediate surface is preferably perpendicular to the sliding direction (rotational direction), but inclined forward from the anti-sealing fluid side to the sealing fluid side. You may set to the direction to do.
(16) An anti-sealing fluid side bevel screw may be provided.
(17) With this configuration, the lubricating oil taken into the recess is dragged to the inclined surface by sliding the shaft, generating a pressure to lift the intermediate surface due to the wedge effect, and increasing the oil film thickness of the intermediate surface As a result, low torque is achieved based on fluid lubrication.
(18) Since the continuous contact portion on the anti-sealing fluid side of the intermediate surface is also lifted by the oil film, the lubricating oil moves to the anti-sealing fluid side of the intermediate surface, but the oil that has reached the anti-sealing fluid side slope is anti-sealing It is returned to the sealed fluid side by a fluid side bevel screw.
(19) By providing a recess as shown in the following embodiment, the effects (17) and (18) can be applied to both rotations.
(20) Further, in this configuration, since the inclined surface only acts to increase the oil film thickness of the wake portion in the axial sliding direction, there is no effect of positively feeding the lubricating oil to the atmosphere side. In the unlikely event that the pumping force of the screw on the atmosphere side may be reduced, the lubricating oil does not leak.

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

First embodiment ...
FIG. 1 shows a cross section of a main part of a sealing device (oil seal) 1 according to a first embodiment of the present invention. FIG. 2A shows an enlarged view of the main part of FIG. The sealing device 1 according to the embodiment is a double-rotating seal and is configured as follows.

That is, first, as shown in FIG. 1, a peripheral surface of a shaft (a mating member, not shown) together with an outer peripheral seal portion 4 and a dust strip 5 by a rubber-like elastic body 3 adhered (vulcanized and bonded) to a metal ring 2. A seal lip 6 that is slidably in contact with the seal lip 6 is provided, and a sealing fluid side inclined surface 7 and an anti-sealing fluid side inclined surface 8 are provided at the tip sliding portion of the seal lip 6. An intermediate surface (flat surface) 9 is provided. The intermediate surface 9 is formed in a cylindrical shape and contacts the entire surface of the shaft when the shaft is inserted, but in its initial state (free state before shaft insertion) as shown in FIG. inclined surface shape at the sealed fluid side C having an inclination angle theta ₁ may be of (conical shape). As a magnitude | size of inclination | tilt angle (theta) ₁ , 0-20 degree is suitable and 0.1-10 degree is still more suitable. As a result, the intermediate surface 9 strongly contacts the peripheral surface of the shaft at a portion on the anti-sealing fluid side D (a contact portion 15 that continues on the circumference described later).

  On the anti-sealing fluid side inclined surface 8, there is a positive screw portion 10 that acts to push the sealing fluid back to the sealing fluid side C by a pumping action when the shaft rotates in the positive direction (forward rotation, arrow E in FIG. 2A). There is also provided a reverse screw portion 11 that acts to push the sealing fluid back to the sealing fluid side C by a pumping action when the shaft rotates in the reverse direction (reverse rotation, arrow F in FIG. 2A). .

  The regular screw portion 10 is composed of a group of spiral projections provided on the circumference, and is drawn assuming projections having a triangular cross section in the figure, but the shape is not particularly limited. The direction of the spiral is set so as to incline forward in the positive rotation direction E of the shaft from the anti-sealing fluid side end 10a to the sealing fluid side end 10b. The reverse screw portion 11 is also composed of a spiral projection group provided in a large number on the circumference, and is drawn assuming projections having a triangular cross section in the figure, but the shape is not particularly limited. The direction of the spiral is set so as to incline toward the front in the reverse rotation direction F of the shaft from the anti-sealing fluid side end portion 11a to the sealing fluid side end portion 11b. Although the normal screw portion 10 and the reverse screw portion 11 are alternately provided one by one on the circumference, a plurality of the normal screw portions 10 and the reverse screw portions 11 may be alternately provided like a multiple thread screw. In this case, the screw length may be different.

  A recess 12 is provided in the intermediate surface 9. The concave portion 12 is provided so as to reach the boundary portion 13 between the intermediate surface 9 and the sealed fluid side inclined surface 7 and not reach the boundary portion 14 between the intermediate surface 9 and the anti-sealed fluid side inclined surface 8. A contact portion 15 for a shaft having a predetermined axial width g that is continuous on the circumference is provided at a portion of the twelve anti-sealing fluid side D. In addition, like the screw portions 10 and 11, many of the concave portions 12 have the same shape, and are provided side by side with a constant interval in the circumferential direction.

Of the edge of the recess 12 (boundary line between the recess 12 and the intermediate surface 9), the portion 12a that is forward in the rotation direction when the shaft rotates forward E is from the sealed fluid side C to the anti-sealed fluid side D at this time. Is set to be inclined forward in the rotational direction E (hereinafter also referred to as “one inclined edge 12a”). That is, the portion of the edge of the recess 12 that is forward in the rotational direction when the shaft rotates forward E is inclined in the forward direction of the rotational direction E from the sealed fluid side C to the anti-sealed fluid side D. One inclined edge 12a is formed. Further, a portion 12b which is the front in the rotation direction when the shaft rotates in the reverse direction F on the edge of the recess 12 is inclined in the forward direction in the rotation direction F from the sealed fluid side C to the anti-sealed fluid side D. (Hereinafter also referred to as “the other inclined edge 12b”). In other words, the portion of the edge of the recess 12 that is forward in the rotational direction when the shaft rotates in the reverse direction F is inclined forward from the sealed fluid side C to the anti-sealed fluid side D in this rotational direction F. The other inclined edge 12b is formed. Accordingly, since the recess 12 has inclined edges 12a and 12b opposite to each other at both ends in the circumferential direction, it is formed in a flat trapezoidal shape as shown in the figure as a whole. 12b) and the long bottom side (anti-sealing fluid side edge) are rising surfaces from the bottom surface, and the short bottom side (sealing fluid side edge) is an opening toward the sealing fluid side C. The depth of the concave portion 12 is constant over the entire surface of the concave portion 12, and the rising surface is a plane perpendicular to the intermediate surface 9, but may be inclined so that the fluid can easily flow. Although the inclination angle theta ₃ inclination angle theta ₂ and other inclined edge 12b of the one inclined edge 12a is set to be equal to each other (θ _{2 =} θ _3), different from each other as shown in FIG. 2 (B) (Θ ₂ ≠ θ ₃ , that is, θ ₂ > θ ₃ or θ ₂ <θ ₃ ).

  The sealing device 1 having the above-described configuration is mounted on the inner periphery of the shaft hole of the housing, and the sealing fluid (oil) in the machine leaks out of the machine by being slidably in close contact with the peripheral surface of the rotating shaft inserted through the shaft hole. This is a double-rotating seal, and is characterized in that the following effects are exhibited by the above configuration.

  That is, when the sealing device 1 is mounted, a part of the sealing fluid is taken into the concave portion 12 from the opening portion that opens to the boundary portion 13, and the sealing portion taken into the concave portion 12 when the shaft rotates forward E as shown in FIG. The fluid is dragged by the positive rotation E of the shaft due to its viscosity, flows and converges along one inclined edge 12a provided on the edge of the recess 12 (because the cross-sectional area of the recess 12 gradually decreases). 12 overflows from the intermediate surface 9 to the contact portion 15 (arrow H), and a thick fluid film is formed on the intermediate surface 9, particularly on the contact portion 15 continuous on the circumference. As the pressure, a dynamic pressure for floating the intermediate surface 9 or the contact portion 15 from the shaft is generated. When the shaft rotates in the reverse direction F (FIG. 2), the sealing fluid taken into the recess 12 is dragged by the reverse rotation F of the shaft due to its viscosity, and flows along the other inclined edge 12b provided on the edge of the recess 12 and converges. (Because the cross-sectional area of the concave portion 12 gradually decreases), the condensing portion 12 overflows from the concave portion 12 to the intermediate surface 9 or the contact portion 15, and forms a thick fluid film on the intermediate surface 9, particularly on the contact portion 15 continuous on the circumference. To do. As the pressure, a dynamic pressure for floating the intermediate surface 9 or the contact portion 15 from the shaft is generated. Therefore, a thick fluid film is formed on the intermediate surface 9 or the contact portion 15 when the shaft rotates in the forward direction E or in the reverse direction F, so that dynamic pressure is generated. In any case, a reduction in torque based on fluid lubrication is realized. In addition, it is possible to suppress the sliding lip 6 from sliding and wearing at an early stage. The contact portion 15 provided on the intermediate surface 9 is continuous on the circumference and is in close contact with the circumferential surface of the shaft over the entire circumference, so that leakage at the time of stationary shaft rotation (so-called stationary leakage) is suppressed. You can also.

  In addition, the sealing fluid that flows out from the intermediate surface 9 or the contact portion 15 toward the anti-sealing fluid side inclined surface 8 is the sealing fluid side by the pumping action of the forward screw portion 10 (forward rotation) or the reverse screw portion 11 (reverse rotation). The concave portion 12 and the positive screw portion 10 are pushed back to C so that the positive screw portion 10 can easily push back the sealing fluid flowing out from the one inclined edge 12a to the anti-sealing fluid side inclined surface 8 through the contact portion 15 during forward rotation. If the positional relationship in the circumferential direction is defined, an increase in the amount of pushing back by the positive screw portion 10 is expected, so that the pumping efficiency is improved. Similarly, during reverse rotation, the circumference of the concave portion 12 and the reverse screw portion 11 is such that the reverse screw portion 11 can easily push back the sealing fluid flowing out from the other inclined edge 12b to the anti-sealing fluid side inclined surface 8 through the contact portion 15. If the directional position relationship is defined, an increase in the amount of pushback by the reverse screw portion 11 is expected, so that the pumping efficiency is improved. Specifically, in order to realize these, as the circumferential positional relationship between the concave portion 12 and the both screw portions 10 and 11, the positive screw portion 10 (for example, the left of the two positive screw portions 10 in FIG. A concave portion between the normal screw portion 10) and the reverse screw portion 11 (for example, the right reverse screw portion 11 of the two reverse screw portions 11 in FIG. 2A) disposed on the rear side in the normal rotation direction E. 12 is preferably arranged.

  Various shapes of the concave portion 12 are conceivable as long as the function (concentrates fluids for both forward rotation and reverse rotation to generate dynamic pressure) is achieved.

That is, in the first embodiment, the planar shape of the recess 12 is a trapezoidal shape. However, since it is the inclined edges 12a and 12b at both ends in the circumferential direction that perform the function, such inclined edges 12a and 12b are provided. As long as it has, the shape of the recess 12 is not limited. For example, in the example of FIG. 4, the trapezoidal shape is divided into two in the circumferential direction, that is, the groove-shaped recess 12A having a certain width having one inclined edge 12a and the width having a certain width having the other inclined edge 12b. A groove-like recess 12B is provided side by side in the circumferential direction. 4A shows the case where θ ₂ = θ ₃ , and FIG. 4B shows the case where θ ₂ ≠ θ ₃ .

  Further, a portion 12a that is forward in the rotational direction when the shaft rotates forward in the edge of the concave portion 12 and a portion 12b that is forward in the rotational direction when the shaft is reversely rotated in the edge of the concave portion 12 are respectively one of them. If the portion is set to be inclined in the forward direction of the rotation direction from the sealed fluid side C to the anti-sealed fluid side D (if the inclined edges 12a and 12b are provided in part), the fluid It is thought that the dynamic pressure is generated by converging. Therefore, it is only necessary that at least a part of each part is set to the inclined direction. For example, in the example of FIG. 5, the concave portion 12 has a planar arc shape (a part of the ellipse is cut out and the cutout portion is an opening), and from the boundary portion 13 of the intermediate surface 9 and the sealed fluid side inclined surface 7. The parts reaching the center line 0 of the ellipse are inclined edges 12a and 12b that meet the above conditions. In this way, the inclined edges 12a and 12b may be curved.

  In addition, the shape of the recess 12 is formed by inclining at least a part of the edge of the recess 12, so that the forward rotation direction E is directed forward in the cross-sectional area of the recess 12 (on each plane including the central axis of the sealing device 1). The cross-sectional area at the time of cutting may be a shape that gradually decreases, and the cross-sectional area of the concave portion 12 (when cutting in each plane including the central axis of the sealing device 1) is also directed forward in the reverse rotation direction F. Any shape that gradually reduces the cross-sectional area) may be used.

Second embodiment ...
FIG. 6 shows a cross section of the main part of a sealing device (oil seal) 1 according to the second embodiment of the present invention. FIG. 7A shows an enlarged view of the main part of FIG. FIG. 7 (B) is a view in the direction of the arrow I in FIG. 7 (A), and shows an annular intermediate surface 9 developed in a planar shape. The sealing device 1 according to the embodiment is a double-rotating seal and is configured as follows.

That is, first, as shown in FIG. 6, a peripheral surface of a shaft (a mating member, not shown) together with an outer peripheral seal portion 4 and a dust lip 5 by a rubber-like elastic body 3 adhered (vulcanized and bonded) to a metal ring 2. A seal lip 6 that is slidably in contact with the seal lip 6 is provided, and a sealing fluid side inclined surface 7 and an anti-sealing fluid side inclined surface 8 are provided at the tip sliding portion of the seal lip 6. An intermediate surface (flat surface) 9 is provided. The intermediate surface 9 is formed in a cylindrical surface shape and contacts the entire surface of the shaft when the shaft is inserted, but in its initial state (free state before shaft insertion) as shown in FIG. inclined surface shape at the sealed fluid side C having an inclination angle theta ₁ may be of (conical shape). As a magnitude | size of inclination | tilt angle (theta) ₁ , 0-20 degree is suitable and 0.1-10 degree is still more suitable. As a result, the intermediate surface 9 strongly contacts the peripheral surface of the shaft at a portion on the anti-sealing fluid side D (a contact portion 15 that continues on the circumference described later).

  On the anti-sealing fluid side inclined surface 8, there is a positive screw portion 10 that acts to push the sealing fluid back to the sealing fluid side C by a pumping action when the shaft rotates in the positive direction (forward rotation, arrow E in FIG. 7A). Also provided is a reverse screw portion 11 that acts to push the sealing fluid back to the sealing fluid side C by a pumping action when the shaft rotates in the reverse direction (reverse rotation, arrow F in FIG. 7A). .

  The regular screw portion 10 is composed of a group of spiral projections provided on the circumference, and is drawn assuming projections having a triangular cross section in the figure, but the shape is not particularly limited. The direction of the spiral is set so as to incline forward in the positive rotation direction E of the shaft from the anti-sealing fluid side end 10a to the sealing fluid side end 10b. The reverse screw portion 11 is also composed of a spiral projection group provided in a large number on the circumference, and is drawn assuming projections having a triangular cross section in the figure, but the shape is not particularly limited. The direction of the spiral is set so as to incline toward the front in the reverse rotation direction F of the shaft from the anti-sealing fluid side end portion 11a to the sealing fluid side end portion 11b. Although the normal screw portion 10 and the reverse screw portion 11 are alternately provided one by one on the circumference, a plurality of the normal screw portions 10 and the reverse screw portions 11 may be alternately provided like a multiple thread screw. In this case, the screw length may be different.

  A recess 12 is provided in the intermediate surface 9. The concave portion 12 is provided so as to reach the boundary portion 13 between the intermediate surface 9 and the sealed fluid side inclined surface 7 and not reach the boundary portion 14 between the intermediate surface 9 and the anti-sealed fluid side inclined surface 8. A contact portion 15 for a shaft having a predetermined axial width g that is continuous on the circumference is provided at a portion of the twelve anti-sealing fluid side D. In addition, like the screw portions 10 and 11, many of the concave portions 12 have the same shape, and are provided side by side with a constant interval in the circumferential direction.

Of the bottom surface of the recess 12, the portion 12 c that is forward in the rotational direction when the shaft rotates forward E is set to have an inclined surface that gradually decreases in depth toward the front in the rotational direction E at this time. (Hereinafter also referred to as “one inclined bottom surface 12c”). That is, in the bottom surface of the recess 12, one of the inclined surface-shaped slopes whose depth gradually decreases toward the front in the rotational direction E at the front portion in the rotational direction when the shaft rotates forward E. A bottom surface 12c is formed. Further, a portion 12d which is the front in the rotation direction when the shaft rotates in the reverse direction F on the bottom surface of the recess 12 is set to have an inclined surface shape whose depth gradually decreases toward the front in the rotation direction F at this time. (Hereinafter also referred to as “the other inclined bottom surface 12d”). That is, in the bottom surface of the concave portion 12, the portion that becomes the front in the rotation direction when the shaft rotates in the reverse direction F, the other inclination of the inclined surface shape whose depth gradually decreases toward the front in the rotation direction F at this time. A bottom surface 12d is formed. Accordingly, since the recess 12 has inclined bottom surfaces 12c and 12d opposite to each other at both ends in the circumferential direction, the recess 12 is formed in a triangular shape as shown in FIG. 7B as a whole. (Inclined bottom surfaces 12c and 12d) are connected to the intermediate surface 9 at their respective ends. The planar shape of the recess 12 is a rectangular shape, its anti-sealing fluid side edge is a rising surface from the bottom surface, and the sealing fluid side edge is an opening toward the sealing fluid side C. The bottom surface of the recess 12 is a combination of two inclined bottom surfaces 12c and 12d. As shown in FIG. 7C, a parallel surface 12e parallel to the intermediate surface 9 is a third surface between the inclined bottom surfaces 12c and 12d. It may be provided as. Although the inclination angle theta ₅ of the inclination angle theta ₄ and the other inclined bottom surface 12d of one of the inclined bottom surface 12c is set to be equal to each other (θ _{4 =} θ _5), to each other as shown in FIG. 7 (D) They may be set differently (θ ₄ ≠ θ ₅ , that is, θ ₄ > θ ₅ or θ ₄ <θ ₅ ). In the example of FIG. 7D, the recesses 12C set to θ ₄ > θ ₅ and the recesses 12D set to θ ₄ <θ ₅ are alternately provided on the circumference.

  The sealing device 1 having the above-described configuration is mounted on the inner periphery of the shaft hole of the housing, and the sealing fluid (oil) in the machine leaks out of the machine by being slidably in close contact with the peripheral surface of the rotating shaft inserted through the shaft hole. This is a double-rotating seal, and is characterized in that the following effects are exhibited by the above configuration.

  That is, when the sealing device 1 is mounted, a part of the sealing fluid is taken into the concave portion 12 from the opening portion that opens to the boundary portion 13, and when the shaft rotates in the forward direction E, the sealing fluid taken into the concave portion 12 has a shaft due to its viscosity. Of the recess 12 and flows along one inclined bottom surface 12c provided on the bottom surface of the recess 12 (because the cross-sectional area of the recess 12 is gradually reduced). Overflowing to the contact portion 15, a thick fluid film is formed on the intermediate surface 9 or the contact portion 15. As the pressure, a dynamic pressure for floating the intermediate surface 9 or the contact portion 15 from the shaft is generated. Further, as shown in FIG. 8, when the shaft rotates in the reverse direction F, the sealing fluid taken into the recess 12 is dragged by the viscosity of the shaft in the reverse rotation F and flows along the other inclined bottom surface 12d provided on the bottom surface of the recess 12. (The arrow K) because the cross-sectional area of the concave portion 12 gradually decreases, overflows from the concave portion 12 to the intermediate surface 9 through the contact portion 15 while converging, and a thick fluid film is formed on the intermediate surface 9 through the contact portion 15. Form. As the pressure, a dynamic pressure for floating the intermediate surface 9 or the contact portion 15 from the shaft is generated. Therefore, a thick fluid film is formed on the intermediate surface 9 or the contact portion 15 when the shaft rotates in the forward direction E or in the reverse direction F, so that dynamic pressure is generated. In any case, a reduction in torque based on fluid lubrication is realized. In addition, it is possible to suppress the sliding lip 6 from sliding and wearing at an early stage. The contact portion 15 provided on the intermediate surface 9 is continuous on the circumference and is in close contact with the circumferential surface of the shaft over the entire circumference, so that leakage at the time of stationary shaft rotation (so-called stationary leakage) is suppressed. You can also.

  Various shapes of the concave portion 12 are conceivable as long as they fulfill their functions (concentrate fluids for both forward rotation and reverse rotation to generate dynamic pressure).

  That is, in the second embodiment, the concave portion 12 has a rectangular planar shape. However, since the function is performed by the pair of inclined bottom surfaces 12c and 12d, the concave portion 12 has the inclined bottom surfaces 12c and 12d. The shape of 12 is not limited. For example, in the example of FIG. 9, the planar shape of the recess 12 is a trapezoid instead of a rectangle, and in this trapezoidal shape, the axis of the edge of the recess 12 (the boundary line between the recess 12 and the intermediate surface 9) is rotated forward E. In this case, the portion 12a that is forward in the rotational direction is set to be inclined in the forward direction in the rotational direction E from the anti-sealing fluid side D to the sealing fluid side C. Further, a portion 12b which is the front in the rotational direction when the shaft rotates in the reverse direction F on the edge of the recess 12 is inclined in the forward direction in the rotational direction F from the anti-sealing fluid side D to the sealing fluid side C. Is set to

  As the shape of the recess 12, at least a part of the bottom surface of the recess 12 is inclined so that the forward rotation direction E is cut forward in the cross-sectional area of the recess 12 (each plane including the central axis of the sealing device 1). The cross-sectional area at the time of cutting may be a shape that gradually decreases, and the cross-sectional area of the recess 12 in the reverse rotation direction F (cutting when cut in each plane including the central axis of the sealing device 1) Any shape can be used as long as the area is gradually reduced. Further, as described above, the circumferential positional relationship between the concave portion 12 and the screw portions 10 and 11 is the positive screw portion 10 (for example, the left positive screw portion 10 of the three positive screw portions 10 in FIG. 7A). And a concave portion 12 (for example, FIG. 7) between the reverse screw portion 11 (for example, the right reverse screw portion 11 of the three reverse screw portions 11 in FIG. 7A) arranged on the rear side in the forward rotation direction E. It is preferable to arrange the central recess 12) among the three recesses 12 in (A).

Sectional drawing of the principal part of the sealing device which concerns on 1st Example of this invention. (A) is an enlarged view of the main part of FIG. 1, (B) is a diagram showing another example of the concave shape Operation explanatory diagram of the sealing device The figure which shows the other example of a shape of a recessed part with (A) and (B) The figure which shows the other example of a recessed part shape Sectional drawing of the principal part of the sealing device which concerns on 2nd Example of this invention. 6A is an enlarged view of the main part of FIG. 6, FIG. 7B is a view taken in the direction of the arrow I in FIG. 7A, and FIGS. (A) is an operation explanatory view of the sealing device, (B) is a view in the direction of arrow J in FIG. 8 (A). The figure which shows the other example of a recessed part shape Sectional drawing of the principal part of the sealing device which concerns on a prior art example

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sealing device 2 Metal ring 3 Rubber-like elastic body 4 Peripheral seal part 5 Dustrip 6 Seal lip 7 Sealed fluid side inclined surface 8 Anti-sealed fluid side inclined surface 9 Middle surface 10 Positive thread part 10a, 11a Anti-sealed fluid side end part 10b, 11b Sealed fluid side end portion 11 Reverse screw portion 12 Recessed portion 12a, 12b Inclined edge 12c, 12d Inclined bottom surface 12e Parallel surface 13, 14 Boundary portion 15 Contact portion

Claims (2)

A sealing device in which a mating member such as a rotating shaft relatively rotates in both forward and reverse directions,
Having a seal lip slidably in contact with the peripheral surface of the mating member;
The sealing lip has a sealing fluid side slope and an anti-sealing fluid side slope and an intermediate surface provided between the slopes,
A normal screw portion that acts to push back the sealing fluid by a pumping action when the counterpart member rotates in the forward direction, and a reverse screw portion that acts to push back the sealing fluid by a pumping action when the counterpart member rotates in the reverse direction Are provided on the anti-seal fluid side slope,
A concave portion is provided on the intermediate surface, and the concave portion is provided so as not to reach a boundary portion between the intermediate surface and the anti-seal fluid side inclined surface, and is continuous on the circumference at a portion of the intermediate surface on the anti-seal fluid side of the recess. A contact portion for the mating member is provided,
Of the edge of the recess, at least a part of the portion that is forward in the rotational direction when the counterpart member rotates in the forward direction is inclined forward in the rotational direction from the sealed fluid side to the anti-sealed fluid side. Is set to the orientation
At least a part of the edge of the recess that is forward in the rotational direction when the counterpart member rotates in the reverse direction is inclined forward from the sealed fluid side to the anti-sealed fluid side. A sealing device characterized in that the sealing device is set in an orientation. A sealing device in which a mating member such as a rotating shaft relatively rotates in both forward and reverse directions,
Having a seal lip slidably in contact with the peripheral surface of the mating member;
The sealing lip has a sealing fluid side slope and an anti-sealing fluid side slope and an intermediate surface provided between the slopes,
A normal screw portion that acts to push back the sealing fluid by a pumping action when the counterpart member rotates in the forward direction, and a reverse screw portion that acts to push back the sealing fluid by a pumping action when the counterpart member rotates in the reverse direction Are provided on the anti-seal fluid side slope,
A concave portion is provided on the intermediate surface, and the concave portion is provided so as not to reach a boundary portion between the intermediate surface and the anti-seal fluid side inclined surface, and is continuous on the circumference at a portion of the intermediate surface on the anti-seal fluid side of the recess. A contact portion for the mating member is provided,
Of the bottom surface of the recess, at least a part of the bottom portion of the concave portion that is forward in the rotational direction when the counterpart member rotates in the forward direction is inclined so that the depth gradually decreases toward the front in the rotational direction at this time. Set to
Of the edge of the recess, at least part of the part that is forward in the rotational direction when the counterpart member rotates in the reverse direction is an inclined surface whose depth gradually decreases toward the forward in the rotational direction at this time. The sealing device characterized by being set to.

Images