JP4849235B2 - Sealing device - Google Patents

Description

  The present invention relates to a sealing device that seals between a shaft hole housing and a shaft inserted into the shaft hole housing so as to be rotatable or reciprocally movable in an axial direction in automobiles, general machines, industrial machines, and the like.

As a sealing device used for sealing oil or the like between a shaft hole housing of a device and a rotating shaft inserted therethrough, an oil seal as disclosed in Patent Document 1, for example, is well known.
JP 2002-206644 A

FIG. 5 is a half cross-sectional view showing a conventional sealing device (oil seal) 100 of the same type as that of Patent Document 1, cut along a plane passing through the axis O. That is, the sealing device 100 is integrally formed of a rubber-like elastic material on a reinforcing ring 105 manufactured by stamping press molding of a metal plate or the like, and has a substantially cylindrical gasket portion 101 and its outside space B side. The lip holder portion 102 extending from the end to the inner peripheral side, and toward the in-machine space A side so as to form a substantially U-shaped cross section with the gasket portion 101 and the lip holder portion 102 from the inner peripheral end of the lip holder portion 102 The seal lip 103 that extends, the dust lip 104 that extends from the inner peripheral end of the lip holder portion 102 toward the side opposite to the seal lip 103 (external space B side), the gasket portion 101 and the lip holder portion 102 A reinforcing ring 105 for reinforcement embedded therein and an extension spring 106 fitted to the seal lip 103 are provided.

  The gasket portion 101 is press-fitted into the inner peripheral surface of the shaft hole housing 110 and is appropriately compressed between the reinforcing ring 105 and exhibits a required sealing force and is fixed to the shaft hole housing 110 in the axial direction. Power is given. Further, the seal lip 103 has its inner peripheral seal edge 103a slidably in close contact with the outer peripheral surface of the rotary shaft 120 inserted through the shaft hole housing 110 with an appropriate pressing force. The inner peripheral edge is brought close to the outer peripheral surface of the rotating shaft 120 with a small gap or is slidably in contact with a slight tightening margin.

  However, since this type of sealing device 100 relies only on the pressure contact force derived from the compression reaction force of the gasket portion 101 made of a rubber-like elastic material, the fixing force to the shaft hole housing 110 depends particularly on, for example, the shaft. When the diameter difference Δφ between the inner diameter of the hole housing 110 and the outer diameter of the rotary shaft 120 is large, that is, when the pressure receiving area with respect to the internal pressure of the internal space A is large, even a slight pressure increase in the internal space A moves toward the external space B side. Since the axial load increases, the sealing device 100 may be detached from the shaft hole housing 110.

  For example, when the shaft hole housing 110 is made of a material having a large thermal expansion coefficient such as an aluminum material, the amount of thermal expansion between the reinforcing ring 105 inside the sealing device 100 and the shaft hole housing 110 when the temperature rises. Due to this difference, the amount of radial compression of the gasket portion 101 between the two 105 and 110 is reduced or lost, so that the sealing device 100 may be detached from the shaft hole housing 110 in this case as well.

  In order to prevent such a separation of the sealing device 100 when the temperature rises, the gasket portion 101 is expected to be reduced in the radial compression amount due to a difference in thermal expansion between the reinforcing ring 105 and the shaft hole housing 110, and the gasket is previously determined. It is effective to set the radial compression allowance of the portion 101 large, but in this case, the press-fit resistance when the sealing device 100 is assembled to the inner periphery of the shaft hole housing 110 is increased, and the assembly workability is increased. In addition to the remarkable deterioration, the shaft hole housing 110 and the gasket portion 101 may be damaged.

  The present invention has been made in view of the above points, and the technical problem is that an increase in the axial load due to the pressure in the in-machine space and the gasket portion due to the thermal expansion of the shaft hole housing. It is to prevent the sealing device from being detached from the shaft hole housing by reducing the amount of radial compression.

As a means for effectively solving the above technical problem, the sealing device according to the invention of claim 1 is formed with a gasket portion made of a rubber-like elastic material that is tightly fitted to the inner peripheral surface of the shaft hole housing. An outer peripheral base, a seal lip made of a rubber-like elastic material that extends from the inner peripheral side to the inner space side and is slidably in contact with the outer peripheral surface of the shaft inserted into the shaft hole housing; and the gasket portion attached is fitted into a groove formed between, in the free state and a radial spring having spring characteristics of substantially linear with a diameter larger than the inner peripheral surface at the time conceivable thermal expansion of the shaft hole housing, the A radial spring consists of an annular body cut at one place in the circumferential direction .

  In the above configuration, the radial spring expands to the inner periphery of the shaft hole housing even if the radial compression amount of the gasket portion in close contact with the inner peripheral surface decreases due to the thermal expansion of the shaft hole housing. Since it has a substantially linear spring characteristic following the surface and has a substantially linear spring characteristic, the decrease in the pressure contact force with the inner peripheral surface of the shaft hole housing is small compared to a gasket portion made of a rubber-like elastic material. For this reason, the axial fixing force of the sealing device with respect to the shaft hole housing is compensated. In addition, even if the radial spring is deformed to a reduced diameter, the radial load does not increase non-linearly and abruptly, so that an increase in press-fit resistance when assembled to the inner periphery of the shaft hole housing can be suppressed.

A sealing device according to a second aspect of the present invention is the sealing device according to the first aspect, wherein the radial spring is engaged with a groove or a recess formed in the inner peripheral surface of the shaft hole housing.

According to the sealing device of the first aspect of the present invention, the axial fixing force with the shaft hole housing is compensated by the radial followability of the radial spring, and the excellent radial followability of the radial spring is ensured. , The amount of compression in the radial direction of the gasket part due to the thermal expansion of the shaft hole housing and the separation from the shaft hole housing due to the pressure inside the machine are effectively prevented, and the workability of assembling to the shaft hole housing is not deteriorated. The effect is realized.

According to the sealing device of the second aspect of the present invention, the separation from the shaft hole housing is prevented by locking the groove or recess formed on the inner peripheral surface of the shaft hole housing with the radial spring, and the shaft hole housing Since it does not depend on the pressure contact force of the radial spring and the gasket portion with respect to the inner peripheral surface of the shaft, it is possible to surely prevent the separation without deteriorating the workability of assembling to the shaft hole housing.

  Hereinafter, preferred embodiments of a sealing device according to the present invention will be described with reference to the drawings. First, FIG. 1 is a side view of the sealing device 1 according to the first embodiment in an unmounted state showing a partial cross section, and FIG. 2 is a view of the radial spring 17 used in the first embodiment viewed from a direction parallel to the axis. FIG. 3 is a half cross-sectional view of a mounting state in which the sealing device 1 according to the first embodiment is cut along a plane passing through the axis O.

  The sealing device 1 shown in FIGS. 1 and 3 has a structure integrally formed with a rubber-like elastic material on a reinforcing ring 15 manufactured by stamping press molding of a metal plate or the like. More specifically, a pair of gasket portions 11a, 11a extending in an annular shape along the axial direction on the outer peripheral surface is protruded, and a lip holder portion extending from the end on the outer space B side to the inner peripheral side. 12, a seal lip 13 extending from the inner peripheral end of the lip holder portion 12 toward the in-machine space A side so as to form a substantially U-shaped cross section together with the outer peripheral base portion 11 and the lip holder portion 12, A dust lip 14 extending from the peripheral end toward the side opposite to the seal lip 13 (external space B side), a reinforcing ring 15 embedded across the outer peripheral base portion 11 and the lip holder portion 12, and the seal lip 13 are fitted. And a radial spring 17 fitted and fitted in a relative groove 11b between the gasket portions 11a and 11a.

  The reinforcing ring 15 has a bent shape having a substantially L-shaped cross section including a cylindrical portion 15 a embedded in the outer peripheral base portion 11 and a flange portion 15 b embedded in the lip holder portion 12. The outer peripheral base 11 is a portion that is press-fitted and tightly fitted to the inner peripheral surface 2 a of the shaft hole housing 2 shown in FIG. 3, and is between the cylindrical portion 15 a of the reinforcing ring 15 and the shaft hole housing 2. , 11a are appropriately compressed in the radial direction, and are brought into close contact with the inner peripheral surface 2a of the shaft hole housing 2 with an appropriate surface pressure by the reaction force.

  A seal edge 13 a having a substantially V-shaped cross section is formed on the inner periphery of the seal lip 13 in the vicinity of the tip portion. The seal edge 13 a is a rotation shaft that is rotatably inserted into the inner periphery of the shaft hole housing 2. 3 is slidably in close contact with the outer peripheral surface 3a with an appropriate tightening margin. The rotating shaft 3 corresponds to the shaft described in claim 1.

  Also, the dust lip 14 facing the side opposite to the seal lip 13 has an inner peripheral edge that is close to the outer peripheral surface 3a of the rotating shaft 3 with a small gap or is slidably in contact with a slight tightening margin. It has become so.

  The extension spring 16 is formed by connecting metal coil springs in an annular shape, and is fitted into an annular groove formed on the outer peripheral side of the seal edge 13 a of the seal lip 13, and is attached to the outer peripheral surface 3 a of the rotary shaft 3. This compensates for the tightening force of the seal lip 13 (seal edge 13a).

  The radial spring 17 is made of an annular body made of metal or hard synthetic resin that is cut at one place in the circumferential direction. Therefore, the radial spring 17 can be elastically deformed in the direction of diameter expansion / contraction, and in a free state. The shaft hole housing 2 has a larger diameter than the inner peripheral surface 2a at the time of thermal expansion that can be assumed. Preferably, the corners on the cross section of the radial spring 17 are chamfered or rounded so that the gasket portions 11a, 11a made of a rubber-like elastic material are not damaged.

  As shown in FIG. 3, the sealing device 1 according to the first embodiment configured as described above has the gasket portions 11 a and 11 a of the outer peripheral base portion 11 as shafts so that the seal lip 13 faces the interior space A side. The inner peripheral surface 2a of the hole housing 2 is tightly fitted, and a radial spring 17 is press-fitted into the inner peripheral surface 2a so that the inner peripheral seal edge 13a of the seal lip 13 can slide on the outer peripheral surface 3a of the rotary shaft 3. Close to. For this reason, it is possible to prevent the sealing target oil existing in the in-machine space A from leaking from the shaft periphery to the out-of-machine space B, and to prevent foreign matter from entering from the out-of-machine space B by the dust seal 14.

  In the mounted state shown in FIG. 3, the radial spring 17 disposed on the outer periphery of the outer peripheral base portion 11 and fitted in the relative groove portion 11b between the gasket portions 11a and 11a is appropriately reduced in diameter from the free state. Further, it is in pressure contact with the inner peripheral surface 2a of the shaft hole housing 2 with a sufficient diameter expansion force, and supplements the axial fixing force of the sealing device 1 due to the pressure contact force of the gasket portions 11a and 11a. For this reason, the separation of the sealing device 1 from the shaft hole housing 2 due to the pressure in the in-machine space A is effectively prevented.

  Here, when the shaft hole housing 2 is thermally expanded due to an increase in the in-machine temperature accompanying the driving of the device, the diameter of the inner peripheral surface 2a increases. At this time, the diameter of the reinforcing ring 15 in the sealing device 1 is also expanded by thermal expansion. In particular, when the shaft hole housing 2 is made of a material having a large thermal expansion coefficient such as an aluminum material, Since the difference in the amount of thermal expansion from the shaft hole housing 2 becomes large, the amount of compression in the radial direction of the gasket portions 11a and 11a between the two 15 and 2 decreases. Since the rubber-like elastic material forming the gasket portions 11a and 11a has a non-linear spring characteristic, the pressure contact force with respect to the inner peripheral surface 2a of the shaft hole housing 2 is reduced as the radial compression amount is reduced. It decreases rapidly.

  However, the radial spring 17 provided between the gasket portions 11a and 11a has a larger diameter than the inner peripheral surface 2a at the time of thermal expansion that can be assumed by the shaft hole housing 2 in the free state. The pressure contact state is maintained by following the diameter expansion of the inner peripheral surface 2a of the housing 2. Moreover, since this radial spring 17 has a substantially linear spring characteristic, the decrease in the pressure contact force against the inner peripheral surface 2a of the shaft hole housing 2 is moderate as compared with the gasket portions 11a, 11a made of rubber-like elastic material. . For this reason, the axial fixing force of the sealing device 1 with respect to the shaft hole housing 2 is compensated by the radial spring 17, and the separation of the sealing device 1 is effectively prevented.

  In addition, since the gasket parts 11a and 11a also maintain a close state following the diameter expansion of the inner peripheral surface 2a of the shaft hole housing 2 due to thermal expansion, the required sealing performance is maintained.

  Further, when the sealing device 1 is press-fitted into the inner peripheral surface 2a of the shaft hole housing 2 and assembled, the radial spring 17 is deformed and reduced, and the increase in the diameter expansion force of the radial spring 17 is linear. Therefore, the press-fitting resistance of the radial spring 17 does not increase rapidly, and the assembly of the sealing device 1 does not become difficult. Moreover, as described above, since the radial spring 17 compensates the axial fixing force of the sealing device 1 by the gasket portions 11a and 11a, it is not necessary to set the compression allowance of the gasket portion 11a so large, and therefore the sealing device. When press-fitting 1 to the inner peripheral surface 2a of the shaft hole housing 2 and assembling, it is possible to effectively prevent the gasket portion 11a from being peeled off or damaged by press-fitting resistance.

  Next, FIG. 4 is a half sectional view of a mounting state in which the sealing device 1 according to the second embodiment of the present invention is cut along a plane passing through the axis O.

  In this embodiment, the sealing device 1 itself is basically the same as the first embodiment described above, except that a groove 2b continuous in the circumferential direction is formed on the inner peripheral surface 2a of the shaft hole housing 2. The outer peripheral portion of the radial spring 17 which is disposed on the outer periphery of the outer peripheral base portion 11 of the sealing device 1 and is fitted in the groove portion 11b between the gasket portions 11a and 11a is engaged with the groove 2b. It is in. The radial spring 17 also has a larger diameter than the inner peripheral surface 2a during thermal expansion that can be assumed by the shaft hole housing 2 in a free state.

  Therefore, according to this configuration, the sealing device 1 from the shaft hole housing 2 is provided by the radial spring 17 engaged with both the gasket portions 11a and 11a of the outer peripheral base portion 11 of the sealing device 1 and the groove 2b of the shaft hole housing 2. Detachment is reliably prevented. Moreover, since this prevention of detachment does not depend on the pressure contact force of the radial spring 17 and the gasket portions 11a and 11a with respect to the inner peripheral surface 2a of the shaft hole housing 2, the assembly by press-fitting the sealing device 1 into the shaft hole housing 2 is performed. Workability does not deteriorate.

1 is a side view of a sealing device according to a first embodiment of the present invention in an unmounted state showing a partial cross section. It is the figure which looked at the radial spring used in a 1st form from the direction parallel to the axial center O in FIG. 1 is a half cross-sectional view of a mounting state in which a sealing device according to a first embodiment of the present invention is cut along a plane passing through an axis O. FIG. It is a half sectional view of the wearing state which shows the sealing device by the 2nd form of the present invention by cutting with the plane which passes along axis O. FIG. 10 is a half sectional view showing a conventional sealing device by cutting along a plane passing through an axis O.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sealing device 11 Outer peripheral base part 11a Gasket part 11b Groove part 12 Lip holder part 13 Seal lip 14 Dustrip
15 Reinforcement ring
16 Extension spring
17 Radial spring
2 Shaft hole housing 2a Inner peripheral surface 2b Groove 3 Rotating shaft 3a Outer peripheral surface A In-machine space B Out-of-machine space

Claims (2)

An outer peripheral base portion (11) formed with a gasket portion (11a) made of a rubber-like elastic material that is tightly fitted to the inner peripheral surface (2a) of the shaft hole housing (2), and an internal space (A) from the inner peripheral side. A seal lip (13) made of a rubber-like elastic material extending slidably and in close contact with an outer peripheral surface (3a) of a shaft (3) inserted through the shaft hole housing (2); and the gasket portion (11a) is fitted and fitted in the groove (11b) formed between them, and in a free state, has a larger diameter than the inner peripheral surface (2a) at the time of thermal expansion that can be assumed by the shaft hole housing (2). A sealing device comprising: a radial spring (17) having a linear spring characteristic , wherein the radial spring (17) is formed of an annular body cut at one place in a circumferential direction . The sealing device according to claim 1, wherein the radial spring (17) is locked to a groove (2b) or a recess formed in the inner peripheral surface (2a) of the shaft hole housing (2) .

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