Oil seal structure

Abstract

To provide an oil seal structure that reduces the burden required for maintenance. [Solution] The oil seal structure 10 includes an oil seal 40 that seals the gap S between the rotating shaft 30 inserted through the housing 20 and the housing 20, and a dust cover 50 that is fixed to the rotating shaft 30 so as to rotate together with the rotating shaft 30 and covers the oil seal 40. The space surrounded by the rotating shaft 30, the oil seal 40 and the dust cover 50 is the target space S1, and a hole 70 that connects the target space S1 and the external space SA relative to the housing 20 is provided in the installation portion 21S of the housing 20 where the oil seal 40 is installed and in the oil seal 40, and a cap 72 that closes the hole 70 is provided.

Description

Technical Field

[0001] The present invention relates to an oil seal structure including an oil seal and a dust cover.

Background Art

[0002] An oil seal structure used in a power transmission device of a vehicle may be submerged in some cases when traveling on a river or a muddy road. In an end face contact type oil seal structure having mud resistance, two rotating members forming a sealed gap may move relative to each other in the axial direction. The generation of a gap between the lip and the thrust surface due to the relative movement significantly degrades the seal performance. To solve this problem, in the oil seal structure of Patent Document 1, when the lip is displaced in the axial direction, the thrust surface moves relative to the axial direction so as to cancel the displacement. Thereby, the contact of the two rotating members is maintained and the seal performance is suitably ensured.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] On the other hand, the continuation of the sliding at the tip of the lip causes the depletion of the lubricant over time at the tip of the lip. For this reason, in the above-described oil seal structure, a technique for reducing the load required for lip maintenance is expected.

Means for Solving the Problems

[0005] An oil seal structure for solving the above problems comprises an oil seal that seals the gap between a rotating shaft inserted through the housing and the housing, and a dust cover fixed to the rotating shaft so as to rotate together with the rotating shaft and covering the oil seal, wherein the space surrounded by the rotating shaft, the oil seal and the dust cover is the target space, and holes connecting the target space to the external space relative to the oil seal structure and the housing are provided in the installation portion of the housing on which the oil seal is installed and in the oil seal, and a cap is provided in the external space to close the hole. [Effects of the Invention]

[0006] According to the present invention, the space enclosed by the oil seal, dust cover, and rotating shaft communicates with the outside space by opening the cap. Therefore, lubricant can be supplied to the space from the outside space through holes provided in the installation part and the oil seal. As a result, the burden required for maintenance of the oil seal structure is reduced. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 is a diagram showing the cross-sectional structure of the oil seal structure together with the motor unit. [Figure 2] Figure 2 is a partial cross-sectional view showing a part of the oil seal structure. [Figure 3] Figure 3 is a partial cross-sectional view showing a first modified example of the oil seal structure. [Figure 4] Figure 4 is a partial cross-sectional view showing a second modified example of the oil seal structure. [Modes for carrying out the invention]

[0008] Hereinafter, one embodiment of the present invention will be described with reference to Figures 1 and 2. Figure 1 is a configuration diagram showing a cross-sectional view of the oil seal structure 10, a part of the housing 20, and the rotating shaft 30. Figure 2 is a partial cross-sectional view showing a part of the oil seal structure 10, and shows a portion above the center line in a cross-section that includes the center line of the rotating shaft 30.

[0009] As shown in Figure 1, the motor unit 100 comprises a vent pipe 110, a housing 20, and a rotating shaft 30. The vent pipe 110 is connected to an intake pipe that supplies intake air to the intake manifold of an internal combustion engine. The vent pipe 110 supplies air flowing from outside the vehicle through an air cleaner into the housing 20 to cool the inside of the housing 20 and to discharge foreign matter from the housing 20. The enlarged diameter portion of the rotating shaft 30 and the housing 20 are separated by a gap S in the axial direction D1 of the enlarged diameter portion. The gap S communicates with the external space SA between the oil seal structure 10 and the housing 20.

[0010] As shown in Figure 2, the interior of the housing 20 houses a portion of the rotating shaft 30 extending in the axial direction D1, and electrical equipment connected to the rotating shaft 30. The rotating shaft 30 is inserted into the interior of the housing 20 through an opening 20H along the axial direction D1.

[0011] The oil seal structure 10 comprises an oil seal 40 and a dust cover 50. The oil seal 40 seals the gap S between the housing 20 and the rotating shaft 30. The dust cover 50 is fixed to the rotating shaft 30 so as to rotate with the rotating shaft 30 and covers the oil seal 40 on the outside of the housing 20.

[0012] The dust cover 50 comprises a sliding contact portion 50A and an outer peripheral covering portion 50B. The sliding contact portion 50A is the bottom wall of the dust cover 50, which has a bottomed cylindrical shape. The sliding contact portion 50A has a disc shape that widens in the radial direction R1 of the rotating shaft 30, and the rotating shaft 30 is inserted through it. The sliding contact portion 50A is positioned on the opposite side of the oil seal 40 in the axial direction D1 and covers the oil seal 40 in the axial direction D1. The sliding contact portion 50A is fixed to the enlarged diameter portion of the outer peripheral surface 31S of the rotating shaft 30.

[0013] The outer peripheral covering portion 50B is the peripheral wall of the dust cover 50, which has a bottomed cylindrical shape. The outer peripheral covering portion 50B has a cylindrical shape that extends in the axial direction D1 from the sliding contact portion 50A. The outer peripheral covering portion 50B is positioned to cover the oil seal 40 on the outside of the radial direction R1 relative to the oil seal 40. The oil seal 40 and the dust cover 50 are separated by a labyrinthine gap S that bends from the radial direction R1 to the axial direction D1.

[0014] The oil seal 40 comprises a press-fit member 41, a connecting member 42, a sealing member 43, and a side lip 45. The press-fit member 41 and the connecting member 42 are fixed to the housing 20 and support the sealing member 43 and the side lip 45.

[0015] The press-fit member 41 has an annular shape through which the rotating shaft 30 is inserted and is fixed to the housing 20 so as to fit into the housing 20 along the axial direction D1. The connecting member 42 has an annular shape through which the rotating shaft 30 is inserted and is located on the opposite side of the press-fit member 41 in the axial direction D1. The connecting member 42 is fixed to the press-fit member 41 so as to protrude inward from the press-fit member 41 in the radial direction R1.

[0016] The sealing member 43 has an annular shape through which the rotating shaft 30 is inserted, and is sandwiched between the housing 20 and the press-fit member 41 in an axial direction D1, thereby sealing the space between the housing 20 and the press-fit member 41. The tip of the sealing member 43 is provided with a sealing portion 47 and a dust lip 44. The sealing member 43 is fixed to the press-fit member 41 such that the sealing portion 47 and the dust lip 44 slide against the outer circumferential surface 31S via a lubricant G. The sealing portion 47 has a tongue shape that contacts the outer circumferential surface 31S over the entire circumference of the rotating shaft 30, suppressing the intrusion of moisture and other substances into the housing 20 from the gap S. The dust lip 44 has a tongue shape that contacts the outer circumferential surface 31S over the entire circumference of the rotating shaft 30.

[0017] The side lip 45 has an annular shape that follows the outer circumferential surface 31S of the rotating shaft 30. The side lip 45 has a tongue-shaped extension that extends from the connecting member 42 toward the sliding contact portion 50A of the dust cover 50 along the entire circumference of the rotating shaft 30. The side lip 45 is fixed to the connecting member 42 such that the lip tip 46 of the side lip 45 slides against the sliding contact portion 50A. The side lip 45 and the sliding contact portion 50A separate the target space S1, which is the space enclosed by the rotating shaft 30, the oil seal 40, and the dust cover 50. The sliding contact portion 46T of the side lip 45 sliding against the dust cover 50 separates the target space S1 from the outer space S2 radially R1 with respect to the target space S1 by a gap S. The target space S1 communicates with the external space SA via the outer space S2. The side lip 45 suppresses the intrusion of foreign matter from the outer space S2 towards the target space S1.

[0018] The oil seal structure 10 includes a single communication hole 70 that penetrates the housing 20 and the oil seal 40. The communication hole 70 penetrates the mounting portion 21S of the housing 20 and the press-fitting member 41 of the oil seal 40. The mounting portion 21S of the housing 20 is a part of the housing 20 that is exposed to the external space SA and is the part of the housing 20 that supports the oil seal 40. The communication hole 70 connects the target space S1 to the external space SA.

[0019] The oil seal structure 10 includes one grease supply pipe 71. The grease supply pipe 71 is inserted into the communication hole 70. The tip 71T of the grease supply pipe 71 faces the contact portion 50A in the target space S1 so as to supply the lubricant G accommodated in the grease supply pipe 71 or the lubricant G supplied to the grease supply pipe 71 to the vicinity of the sliding contact portion 46T. Thereby, the grease supply pipe 71 directly applies the lubricant G to the side lip 45 to lubricate the side lip 45, or applies the lubricant G to the central portion of the rotating shaft 30 and lubricates the side lip 45 with the lubricant G that spreads by centrifugal force.

[0020] The grease supply pipe 71 has a cap 72 in the external space SA. The cap 72 is attached to the base end portion of the grease supply pipe 71 in the external space SA. The cap 72 closes the communication hole 70 that communicates the target space S1 and the external space SA. The constituent material of the cap 72 preferably seals at the base end portion of the grease supply pipe 71 to prevent moisture in the external space SA from entering the grease supply pipe 71.

[0021] In addition, the base end portion of the grease supply pipe 71 may be connected to an intake pipe, similar to the ventilation pipe 110 connected to the housing 20. When the grease supply pipe 71 is connected to the intake pipe, it is possible to suppress the mixing of water, foreign matters, etc. into the target space S1 through the grease supply pipe 71. At this time, the grease supply pipe 71 may be integrally connected to the intake pipe together with the ventilation pipe 110, or the grease supply pipe 71 may be separately connected to the intake pipe from the ventilation pipe 110. Similarly in this case, the mixing of water, foreign matters, etc. is suppressed in the grease supply pipe 71.

[0022] Also, the lubricant G in the grease supply pipe 71 can change over time and harden, or can harden depending on the environmental temperature in which the oil seal structure 10 is used. Therefore, in the maintenance using the communication hole 70, after supplying a certain amount of the lubricant G to the target space S1 through the grease supply pipe 71, it is preferable to ensure the conductivity of the grease supply pipe 71 by venting air from the base end portion to the tip 71T of the grease supply pipe 71. [[ID=,14]]

[0023] According to the above embodiment, the following effects can be obtained. (1) The oil seal structure 10 includes a communication hole 70 that connects the target space S1 and the external space SA, and a cap 72 that closes the communication hole 70. The target space S1 communicates with the external space SA when the cap 72 is opened. Therefore, it becomes possible to supply lubricant G from the external space SA to the target space S1 through the communication hole 70. As a result, the burden required for maintenance of the oil seal structure 10 is reduced.

[0024] (2) Furthermore, when the lubrication pipe 71 accumulates lubricant G, the lubricant G dripping from the lubrication pipe 71 enhances the durability of the side lip 45 and, consequently, the durability of the oil seal structure 10.

[0025] The above embodiment can be implemented with the following modifications. The above embodiment and the following modifications can be combined with each other to the extent that they do not contradict each other technically. The cap 72 may be made of a waterproofing material that allows only gases other than water to pass through. Alternatively, the cap 72 may be made of a water-resistant structure such as a labyrinth structure or a porous membrane.

[0026] As shown in Figure 3, the tip portion 71T of the lubrication pipe 71 may be positioned at a distance from the lubricant G storage area within the target space S1, or it may extend to the lubricant G storage area within the target space S1, as shown by the dashed line in Figure 3. The lubricant G storage area may be at the base end in the radial direction R1 within the target space S1, or it may be inside the radial direction R1 of the sliding contact portion 46T. The lubricant G storage area may also be contained within the side lip 45 itself or the dust lip 44 itself.

[0027] In this configuration, the lubrication pipe 71 is configured to be loosely inserted into the communication hole 70. When the target space S1 requires lubricant G, the tip 71T of the lubrication pipe 71 is inserted toward the storage area. This configuration, in which the tip 71T of the lubrication pipe 71 is inserted to such an extent, is effective when the viscosity of the lubricant G is high or when the lubricant G is prone to clogging inside the lubrication pipe 71.

[0028] The lubrication pipe 71 may also be used as a passage for flowing compressed air from the external space SA towards the target space S1. The compressed air blown into the target space S1 will expel any foreign matter that has entered the target space S1 through the gap S. In this case, it is preferable that the tip 71T of the lubrication pipe 71 opens toward the dust cover 50 or the side lip 45 so as not to blow compressed air directly onto the oil seal 40.

[0029] As shown in Figure 4, the cap 72 may be positioned on the mounting portion 21S such that its lower surface is in contact with the mounting portion 21S. The base end of the lubrication pipe 71 may be positioned so as to be substantially flush with the surface of the mounting portion 21S. In this case, the length of the lubrication pipe 71 is shorter compared to a configuration in which the base end of the lubrication pipe 71 protrudes from the mounting portion 21S. This reduces the constraints on the position and dimensions of the lubrication pipe 71 in the surrounding configuration of the housing 20.

[0030] The base end of the lubrication pipe 71 may be connected to an oil gun for supplying lubricant G to the target space S1 after the cap 72 is removed. Alternatively, the base end of the lubrication pipe 71 that has been supplied with lubricant G may be sealed with the cap 72 after the supply of lubricant G, thereby storing the lubricant G inside the lubrication pipe 71. In this case, a negative pressure may be formed inside the lubrication pipe 71 so that the lubrication pipe 71 holds the lubricant G, while the lubricant G drips out due to the decrease in viscosity at high temperatures. This allows the lubricant G to be held and supplied to the target space S1 for a certain period of time, even after maintenance in which the cap 72 is attached. The degree of dripping of lubricant G is adjusted by at least one of the following: viscosity, temperature, pipe diameter, and properties of the inner surface of the pipe. [Explanation of Symbols]

[0031] S...gap, SA...space, R1...radial direction, S1...target space, S2...outer space, 10...oil seal structure, 20...housing, 21S...installation part, 30...rotating shaft, 31S...outer surface, 40...oil seal, 41...outer press-fit part, 42...connecting member, 43...sealing member, 44...dust lip, 45...side lip, 46T...sliding contact part, 47...seal part, 50...dust cover, 70...hole, 71...lubrication pipe, 71T...tip part, 72...cap

Claims

[Claim 1] An oil seal that seals the gap between the rotating shaft inserted into the housing and the housing, A dust cover fixed to the rotating shaft so as to rotate together with the rotating shaft and covering the oil seal on the outside of the housing, An oil seal structure comprising, The space enclosed by the rotating shaft, the oil seal, and the dust cover is the target space, and holes connecting the target space with the external space relative to the oil seal structure and the housing are provided in the installation portion of the housing where the oil seal is installed and in the oil seal itself. The external space is provided with a cap to seal the hole. An oil seal structure characterized by the following features.

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