JP2017122474A - Sealing structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealing structure which can exert a sealing function even in a state that fluid pressure is low.SOLUTION: A chamfer 311 is formed over the whole periphery at a corner at which a sidewall face of an annular groove 310 at a low-pressure side (L) and an external peripheral face of a shaft 300 intersect with each other. A sealing device 10 comprises: a resin-made first seal ring 100 which is arranged so as to tightly adhere to the sidewall face of the annular groove 310 at the low-pressure side (L); and an elastic-body made second seal ring 200 which is arranged so as to tightly adhere to a sidewall face and a groove bottom face of the annular groove 310 at a high-pressure side (H) and the first seal ring 100, and presses the first seal ring 100 toward the low-pressure side (L). An outside diameter of the first seal ring 100 is set larger than an inside diameter of an axial hole internal peripheral face of a housing 400, and an end part 110 of the first seal ring 100 at the external peripheral face side is deflected along the chamfer 311, and slidably arranged at the axial hole internal peripheral face.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a sealing structure for sealing an annular gap between a shaft and a shaft hole of a housing.

  In automotive automatic transmission (AT) and continuously variable transmission (CVT) for automobiles, a sealing device (seal ring) that seals an annular gap between a relatively rotating shaft and a housing is provided in order to maintain hydraulic pressure. Is provided. With reference to FIG.4 and FIG.5, the seal ring which concerns on a prior art example is demonstrated. FIG. 4 is a schematic cross-sectional view showing a state in which the hydraulic pressure is not maintained in the conventional seal ring. FIG. 5 is a schematic cross-sectional view showing a state where the hydraulic pressure is maintained in the seal ring according to the conventional example. In the case of the seal ring 500 according to the conventional example, the seal ring 500 is attached to the annular groove 610 provided on the outer periphery of the shaft 600, and the inner peripheral surface of the shaft hole of the housing 700 through which the shaft 600 is inserted and the side wall surface of the annular groove 610. By being slidably contacted, an annular gap between the shaft 600 and the shaft hole of the housing 700 is sealed.

  In the seal ring 500 used in the above applications, it is required that the sliding torque be sufficiently low. Therefore, the peripheral length of the outer peripheral surface of the seal ring 500 is configured to be shorter than the peripheral length of the inner peripheral surface of the shaft hole of the housing 700, and is configured not to have a tightening allowance. Therefore, in a state where the engine of the automobile is applied and the hydraulic pressure is high, the seal ring 500 is expanded by the hydraulic pressure, and the hydraulic pressure is sufficiently maintained by being in close contact with the inner peripheral surface of the shaft hole and the side wall surface of the annular groove 610. The function is exhibited (see FIG. 5). On the other hand, the seal ring 500 is configured to be separated from the inner peripheral surface of the shaft hole and the side wall surface of the annular groove 610 in a state where no hydraulic pressure is applied due to the stop of the engine (see FIG. 4).

  Thus, in the case of the seal ring 500 according to the conventional example, the sealing function is not exhibited in a state where no hydraulic pressure is applied. For this reason, in the configuration in which the shift control is performed by the oil pumped by the hydraulic pump such as AT and CVT, the seal ring 500 is sealed in the no-load state where the hydraulic pump is stopped (for example, when idling is stopped). The oil returns to the oil pan without being sealed, and the oil in the vicinity of the seal ring 500 disappears. Therefore, when the engine is started (restarted) from this state, the operation is started in a state where there is no oil in the vicinity of the seal ring 500 and there is no lubrication.

JP 2011-80529 A JP 2010-265937 A

  An object of the present invention is to provide a sealing structure capable of exhibiting a sealing function even when the fluid pressure is low.

  The present invention employs the following means in order to solve the above problems.

That is, the sealing structure of the present invention is
A relatively rotating shaft and housing;
A seal that is mounted in an annular groove provided on the outer periphery of the shaft, seals an annular gap between the shaft and the housing, and maintains a fluid pressure in a region to be sealed configured to change the fluid pressure. Equipment,
A sealing structure comprising:
A chamfer is provided over the entire circumference at the intersection of the side wall surface on the low-pressure side and the outer peripheral surface of the shaft in the annular groove,
The sealing device includes:
A resin-made first seal ring disposed so as to be in close contact with the low-pressure side wall surface of the annular groove;
A second seal ring made of an elastic body that is disposed so as to be in close contact with the first seal ring and the side wall surface and the groove bottom surface on the high-pressure side of the annular groove, and presses the first seal ring toward the low-pressure side; ,
With
The outer diameter of the first seal ring is set to be larger than the inner diameter of the inner peripheral surface of the shaft hole in the housing, and the end portion on the outer peripheral surface side of the first seal ring is bent along the chamfer, and the shaft It is slidably provided on the inner peripheral surface of the hole.

  According to the present invention, the first seal ring made of resin is pressed toward the low pressure side by the second seal ring made of an elastic body, so that the state of being in close contact with the side wall surface on the low pressure side in the annular groove is maintained. The Moreover, the edge part of the outer peripheral surface side in a 1st seal ring bends to a low voltage | pressure side along the chamfering provided in the annular groove, and is slidably provided in the axial peripheral surface of a housing. Therefore, the sealing function is exhibited even in a state where the fluid pressure is not acting (no differential pressure is generated) or the fluid pressure is hardly acting (the differential pressure is hardly generated). Therefore, the fluid pressure can be maintained immediately after the fluid pressure in the region to be sealed starts to increase.

  In addition, the end portion of the first seal ring is bent toward the low pressure side, but is bent along the chamfer. Therefore, as in the case where no chamfer is provided, the side wall surface on the low pressure side in the annular groove and the shaft are bent. It will not be damaged by the corners of the intersection with the outer peripheral surface.

  Furthermore, when the fluid pressure is acting (differential pressure is generated), the fluid pressure acts on the bent portion of the end portion on the outer peripheral surface side of the first seal ring. Thereby, since the force which goes to radial direction inner side is added, it can suppress that the sliding torque with a 1st seal ring and the axial-hole inner peripheral surface of a housing increases.

  As described above, according to the present invention, the sealing function can be exhibited even in a state where the fluid pressure is low.

FIG. 1 is a schematic cross-sectional view of a sealing structure according to an embodiment of the present invention. FIG. 2 is an explanatory view illustrating the assembly procedure of the sealing structure according to the embodiment of the present invention. FIG. 3 is a schematic cross-sectional view of a sealing structure according to a modification of the present invention. FIG. 4 is a schematic cross-sectional view showing a state in use of the seal ring according to the conventional example. FIG. 5 is a schematic cross-sectional view showing a state in use of a seal ring according to a conventional example.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be exemplarily described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention only to those unless otherwise specified. . The sealing device according to the present embodiment is used for sealing an annular gap between a relatively rotating shaft and a housing in order to maintain hydraulic pressure in a transmission such as an AT or CVT for an automobile. It is used. Further, in the following description, “high pressure side” means a side that becomes high pressure when differential pressure occurs on both sides of the sealing device, and “low pressure side” means that differential pressure occurs on both sides of the sealing device. This means the side that is at low pressure.

(Example)
With reference to FIGS. 1-3, the sealing structure which concerns on the Example of this invention is demonstrated. FIG. 1 is a schematic cross-sectional view of a sealing structure according to an embodiment of the present invention. In addition, the sealing device in FIG. 1 has shown sectional drawing cut | disconnected by the surface containing a central axis (a shaft and the central axis of a sealing device). FIG. 2 is an explanatory view illustrating the assembly procedure of the sealing structure according to the embodiment of the present invention. FIG. 3 is a schematic cross-sectional view of a sealing structure according to a modification of the present invention. Note that the sealing device in FIG. 3 is a cross-sectional view cut along a plane including a central axis (a shaft and a central axis of the sealing device).

<Configuration of sealing structure and sealing device>
In particular, with reference to FIG. 1, the structure of the sealing structure and the sealing device 10 which concern on the Example of this invention is demonstrated. The sealing structure according to the present embodiment includes a shaft 300 and a housing 400 that rotate relatively, and an annular gap between the shaft 300 and the housing 400 (an inner peripheral surface of the shaft hole through which the shaft 300 in the housing 400 is inserted). And a sealing device 10 for sealing. The sealing device 10 according to the present embodiment is mounted in an annular groove 310 provided on the outer periphery of the shaft 300, and seals an annular gap between the shaft 300 and the housing 400 that rotate relatively. Thereby, the sealing device 10 maintains the fluid pressure in the sealing target region configured such that the fluid pressure (hydraulic pressure in the present embodiment) changes. Here, in the present embodiment, the fluid pressure in the region on the right side in FIG. 1 is configured to change, and the sealing device 10 plays a role of maintaining the fluid pressure in the region to be sealed on the right side in the diagram. Yes. In the state where the engine of the automobile is stopped, the fluid pressure in the sealing target region is low and no load is applied. When the engine is started, the fluid pressure in the sealing target region increases.

  Chamfers 311 are provided over the entire circumference at the intersections of both side walls of the annular groove 310 provided on the shaft 300 and the outer peripheral surface of the shaft 300. The chamfer 311 according to the present embodiment is configured by a tapered surface (so-called C surface).

  The sealing device 10 according to the present embodiment includes a first seal ring 100 made of resin such as polyether ether ketone (PEEK), polyphenylene sulfide (PPS), polytetrafluoroethylene (PTFE), and acrylic rubber (ACM). And a second seal ring 200 made of a rubber-like elastic body such as fluorine rubber (FKM) or hydrogenated nitrile rubber (HNBR).

  The first seal ring 100 according to the present embodiment is a flat washer-shaped member in a state where no external force is received. And the 1st seal ring 100 is arrange | positioned so that it may closely_contact | adhere to the side wall surface of the low voltage | pressure side (L) in the annular groove 310 provided in the axis | shaft 300. FIG. Further, the outer diameter of the first seal ring 100 is set larger than the inner diameter of the inner peripheral surface of the shaft hole in the housing 400. Further, in the first seal ring 100, the end portion 110 on the outer peripheral surface side bends along the low pressure side (L) chamfer 311 in the annular groove 310, and the vicinity of the tip 111 on the high pressure side is in the shaft hole of the housing 400. It is slidably provided on the peripheral surface. The inner diameter of the first seal ring 100 is set larger than the outer diameter of the groove bottom of the annular groove 310. However, you may comprise so that the internal peripheral surface of the 1st seal ring 100 can contact the groove bottom of the annular groove 310 at the time of use.

  The second seal ring 200 according to the present embodiment is a so-called O-ring having a circular cross section. The second seal ring 200 is set to have an inner diameter smaller than the outer diameter of the groove bottom of the annular groove 310 in a state where no external force is applied. The wire diameter of the second seal ring 200 is set larger than the difference between the groove width of the annular groove 310 and the width of the first seal ring 100 in the central axis direction. Thereby, the second seal ring 200 is disposed so as to be in close contact with the first seal ring 100 and the side wall surface and groove bottom surface on the high pressure side (H) of the annular groove 310 provided in the shaft 300. 1 The seal ring 100 has a function of pressing toward the low pressure side (L).

<Assembly procedure for sealing structure>
In particular, the assembly procedure of the sealing structure according to the present embodiment will be described with reference to FIG. First, the first seal ring 100 and the second seal ring 200 are mounted in an annular groove 310 provided in the shaft 300 as shown in FIG. Thereafter, the shaft 300 is inserted into the shaft hole of the housing 400 in the direction of arrow S in the figure. In this process, the vicinity of the opening end portion 410 of the shaft hole of the housing 400 hits the end portion 110 on the outer peripheral surface side of the first seal ring 100, and the end portion 110 is deformed so as to bend in the arrow R direction. Thereby, in the first seal ring 100, the end portion 110 on the outer peripheral surface side bends along the low-pressure side (L) chamfer 311 in the annular groove 310, and the vicinity of the high-pressure side tip 111 is the shaft hole of the housing 400. It will be in the state closely_contact | adhered to the inner peripheral surface.

<Mechanism when using sealing device>
In particular, with reference to FIG. 1, the mechanism at the time of use of the sealing device 10 which concerns on a present Example is demonstrated. FIG. 1 shows a state in which the engine is started and the fluid pressure in the right region is higher than the left region through the sealing device 10.

  As described above, since the first seal ring 100 is pressed toward the low pressure side (L) by the second seal ring 200, the first seal ring 100 is formed on the side wall surface on the low pressure side (L) of the annular groove 310 provided in the shaft 300. The state of being in close contact with each other is maintained. Further, the outer diameter of the first seal ring 100 is set larger than the inner diameter of the inner peripheral surface of the shaft hole in the housing 400. The end portion 110 on the outer peripheral surface side of the first seal ring 100 is bent along the low-pressure side (L) chamfer 311 in the annular groove 310, and the vicinity of the high-pressure side tip 111 is the inner periphery of the shaft hole of the housing 400. It is slidably provided on the surface. Further, the second seal ring 200 is disposed so as to be in close contact with the first seal ring 100 and the side wall surface and groove bottom surface on the high pressure side (H) of the annular groove 310 provided in the shaft 300.

  Therefore, even when the engine is stopped and there is no differential pressure on both sides via the sealing device 10 (no load state), the state where the annular gap between the shaft 300 and the housing 400 is sealed is maintained. . Even when the engine is started and the fluid pressure in the right region is higher than the left region through the sealing device 10, the first seal ring 100 and the second seal ring 200 are almost arranged. It does not change. Therefore, the state where the annular gap between the shaft 300 and the housing 400 is sealed is maintained. Further, when the shaft 300 and the housing 400 are relatively rotated, the first seal ring 100 is kept in close contact with the low pressure side (L) side surface of the annular groove 310, and the contact area is small. It slides between the first seal ring 100 and the inner peripheral surface of the shaft hole of the housing 400. Further, in a state where the differential pressure is generated, fluid pressure (hydraulic pressure) acts on the end portion 110 on the outer peripheral surface side of the first seal ring 100 as indicated by an arrow P in FIG. Thereby, the function of reducing the contact pressure in the vicinity of the high-pressure side tip 111 at the end portion 110 on the outer peripheral surface side of the first seal ring 100 with respect to the inner peripheral surface of the shaft hole of the housing 400 is exhibited. Therefore, sliding between the first seal ring 100 and the low pressure side (L) side surface of the annular groove 310 is more reliably suppressed.

<Excellent point of sealing structure according to this embodiment>
According to the sealing structure according to the present embodiment, the sealing function is exhibited by the sealing device 10 even when there is no differential pressure on both sides via the sealing device 10 (no load state). Therefore, the fluid pressure can be maintained immediately after the fluid pressure in the region to be sealed starts to increase.

  In other words, in an engine having an idling stop function, the hydraulic pressure can be maintained immediately after the hydraulic pressure on the sealing target region side is increased by starting the engine by depressing the accelerator when the engine is stopped. Here, generally, in the case of a resin seal ring, the function of suppressing fluid leakage is not so much exhibited. However, in the sealing device 10 according to the present embodiment, the state in which the annular gap between the shaft 300 and the housing 400 is sealed even in a no-load state is maintained, and thus the function of sufficiently suppressing fluid leakage Is demonstrated. Therefore, even after the operation of the pump or the like is stopped by stopping the engine, it is possible to maintain a state in which the differential pressure is generated for a while. Therefore, in an engine having an idling stop function, when the engine is not stopped so long, the state in which the differential pressure is generated can be maintained. Therefore, when the engine is restarted, the fluid pressure is preferably adjusted immediately after that. Can be retained.

  Moreover, although the edge part of the 1st seal ring 100 bends to the low voltage | pressure side (L), since it bends along the chamfer 311, the low pressure in the annular groove 310 is temporarily provided like the case where chamfer is not provided. The side (L) side wall surface and the outer peripheral surface of the shaft 300 are not damaged by the angle of intersection.

  Further, when fluid pressure is acting (differential pressure is generated), fluid pressure (see arrow P in FIG. 1) is applied to the bent portion of the end portion 110 on the outer peripheral surface side of the first seal ring 100. ) Acts. Thereby, since the force which goes to radial direction inner side is added, it can suppress that the sliding torque between the 1st seal ring 100 and the axial-hole inner peripheral surface of the housing 400 increases.

<Modification>
In FIG. 1, the case where the chamfering 311 provided over the entire circumference at the intersection of the both side wall surfaces of the annular groove 310 provided in the shaft 300 and the outer peripheral surface of the shaft is a tapered surface is shown. However, for example, as shown in FIG. 3, the chamfer 312 may be a surface whose cross section is a curved line (so-called R surface). The modified example shown in FIG. 3 and the above-described embodiment shown in FIG. 1 are the same except for the chamfered shape. Needless to say, the same effects as those of the above-described embodiment can also be obtained in the sealing structure according to the modification shown in FIG. 3 configured as described above.

(Other)
About the 1st seal ring 100, in order to improve the mounting | wearing property to the annular groove 310, you may provide an abutment part in one place of the circumferential direction. Various known techniques can be employed for the joint portion. For example, straight cut, bias cut, step cut, special step cut, etc. can be adopted. Since these are well-known techniques, a detailed description thereof is omitted, but the straight cut is a structure that is straightly cut in the radial direction. The bias cut is a structure that is cut obliquely with respect to the radial direction. In addition, the step cut is a structure that is cut stepwise when viewed from the outer peripheral surface and the inner peripheral surface, and is cut linearly when viewed from both side surfaces, or is stepped when viewed from both side surfaces, and the outer surface and When viewed from the inner peripheral surface, the structure is cut linearly. Further, the special step cut is a structure that is cut in a step shape when viewed from the outer peripheral surface and both side surfaces, and is cut in a straight line when viewed from the inner peripheral surface. In addition, about these cutting structures, it may be formed by shaping | molding besides the case where it forms by cutting literally.

  In the said Example, the case where the 1st seal ring 100 was a member with a flat washer shape in the state which has not received external force was shown. However, the shape of the first seal ring in the present invention is not limited. That is, with respect to the first seal ring, sealing performance is exhibited by closely contacting the low-pressure side wall surface of the annular groove provided on the shaft, and the end on the outer peripheral surface side is along the low-pressure side chamfer of the annular groove. The shape is not limited as long as it bends and slidably contacts the inner peripheral surface of the shaft hole of the housing and exhibits sealing performance. Moreover, in the said Example, the case where the 1st seal ring 100 was mounted | worn with the annular groove 310 provided in the axis | shaft 300 with the flat washer shape was shown. However, the end 110 on the outer peripheral surface side of the first seal ring 100 may be brazed in a state of being bent to some extent in advance before being attached to the annular groove 310.

  Moreover, in the said Example, the case where the 2nd seal ring 200 was an O-ring was shown. However, the second seal ring in the present invention is not limited to the O-ring, and various known techniques such as a square ring can be employed.

DESCRIPTION OF SYMBOLS 10 Sealing device 100 Seal ring 110 End part 111 Tip 200 Seal ring 300 Shaft 310 Annular groove 311 Chamfer 400 Housing 410 Open end

Claims (1)

A relatively rotating shaft and housing;
A seal that is mounted in an annular groove provided on the outer periphery of the shaft, seals an annular gap between the shaft and the housing, and maintains a fluid pressure in a region to be sealed configured to change the fluid pressure. Equipment,
A sealing structure comprising:
A chamfer is provided over the entire circumference at the intersection of the side wall surface on the low-pressure side and the outer peripheral surface of the shaft in the annular groove,
The sealing device includes:
A resin-made first seal ring disposed so as to be in close contact with the low-pressure side wall surface of the annular groove;
A second seal ring made of an elastic body that is disposed so as to be in close contact with the first seal ring and the side wall surface and the groove bottom surface on the high-pressure side of the annular groove, and presses the first seal ring toward the low-pressure side; ,
With
The outer diameter of the first seal ring is set to be larger than the inner diameter of the inner peripheral surface of the shaft hole in the housing, and the end portion on the outer peripheral surface side of the first seal ring is bent along the chamfer, and the shaft A sealing structure characterized by being slidably provided on an inner peripheral surface of a hole.

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