Dust cover for vehicle power transmission system

Abstract

The present invention provides a dust cover for a vehicle power transmission device that can adequately ensure a labyrinth seal structure formed by the dust cover, even when one end of the power transmission shaft is connected to another rotating body via a spigot joint, thereby effectively suppressing the intrusion of foreign matter. [Solution] Since the dust cover 48 has a split structure, it can be fixed to the gearbox 32 after the power transmission shaft 12 has been assembled. Therefore, it is not necessary to fix the dust cover 48 to the power transmission shaft 12 in a position that avoids interference with the bearing 36 provided at the other end of the power transmission shaft 12 and the gearbox 32 that houses the oil seal 46, and the labyrinth seal structure formed by the dust cover 48 can be sufficiently secured, and the intrusion of foreign matter can be suitably suppressed.

Description

Technical Field

[0001] The present invention relates to a dust cover for protecting a bearing that rotatably supports a power transmission shaft and an oil seal that suppresses oil leakage from the bearing in a vehicle power transmission device having the bearing and the oil seal from external dust.

Background Art

[0002] Patent Document 1 discloses a structure in which an oil seal is provided between a shift select shaft and a shaft support hole, and a rubber dust cover that covers the shift select shaft and the shaft support hole is provided.

[0003] In a vehicle power transmission device having a power transmission shaft exposed to the outside from a gearbox, a bearing that rotatably supports the power transmission shaft in the gearbox, and an oil seal that suppresses oil leakage from the bearing, when trying to protect the bearing and the oil seal from external dust, since the power transmission shaft is a rotating body while the gearbox that houses the bearing and the oil seal is non-rotating, a dust cover structure as in Patent Document 1 cannot be applied.

[0004] On the other hand, it is conceivable to fix an annular dust cover to the power transmission shaft and bring it close to the opening of the gearbox that houses the bearing and the oil seal.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, when one end of a power transmission shaft is connected to another rotating body via a spigot joint, axial movement is required to fit the power transmission shaft into the spigot of the joint during assembly. In this case, considering the axial movement during assembly, it is necessary to position the dust cover in a location that avoids interference with the gearbox housing the bearing and oil seal at the other end of the power transmission shaft. This makes it difficult to adequately secure the labyrinth seal structure formed by the dust cover, potentially leading to the easy intrusion of foreign matter such as dust.

[0007] The present invention has been made against the above circumstances, and its objective is to provide a dust cover for a vehicle power transmission device that, even when one end of the power transmission shaft is connected to another rotating body via a spigot joint, does not require the dust cover to be positioned to avoid interference with the gearbox housing the bearing and oil seal at the other end of the power transmission shaft, can sufficiently secure the labyrinth seal structure formed by the dust cover, and can effectively suppress the intrusion of foreign matter. [Means for solving the problem]

[0008] The gist of the first invention is a dust cover for a vehicle power transmission device in which (a) one end is connected to another rotating body via a joint of an interlocking structure, the other end is rotatably supported by a bearing housed in a gearbox, and oil leakage between the opening of the gearbox and the power transmission shaft is suppressed by an oil seal, and (b) the dust cover is composed of a plurality of parts divided into an arc shape to form an annular shape, and is fixed to the gearbox so as to cover the opening of the gearbox when the power transmission shaft is assembled.

[0009] The gist of the second invention is that, in the first invention, (c) the dust cover is composed of two parts having the same shape, each having an arc-shaped main body and a pair of mounting parts that protrude radially from both ends of the main body.

[0010] The gist of the third invention is that, in the first invention, (d) the power transmission shaft has a large-diameter portion that is relatively larger in diameter than the shaft portion of the power transmission shaft at a position facing the inner circumferential surface of the opening of the gearbox, (e) the dust cover has an inner circumferential portion having an inner circumferential edge that is smaller in diameter than the large-diameter portion, and (f) a labyrinth seal structure is formed by a radial passage between the inner circumferential portion and the large-diameter portion having an axial spacing smaller than the distance between the inner circumferential surface of the opening of the gearbox and the outer circumferential surface of the large-diameter portion, and an axial passage between the inner circumferential portion and the large-diameter portion having a radial spacing smaller than the distance between the inner circumferential surface of the opening of the gearbox and the outer circumferential surface of the large-diameter portion.

[0011] The gist of the fourth invention is that, in the third invention, (g) the oil seal is fitted to the inner circumferential surface of the opening of the gearbox, and the oil seal comprises an annular oil seal body fitted to the inner circumferential surface of the opening of the gearbox, a first lip portion and a second lip portion that protrude annularly inward from the oil seal body portion and slide in contact with two locations on the large diameter portion of the power transmission shaft, and a contact portion that protrudes from the oil seal body portion toward the dust cover and abuts against the back surface of the dust cover. [Effects of the Invention]

[0012] According to the dust cover for a vehicle power transmission device of the first invention, it is composed of multiple parts divided into an arc shape to form an annular shape and is fixed to the gearbox so as to cover the opening of the gearbox when the power transmission shaft is assembled. As a result, the dust cover can be attached after the power transmission shaft is assembled, so there is no need to fix the dust cover to the power transmission shaft in a position that avoids interference with the gearbox which houses the bearing and oil seal provided at the other end of the power transmission shaft, and the labyrinth seal structure formed by the dust cover can be sufficiently secured, and the intrusion of foreign matter can be suitably suppressed.

[0013] According to the dust cover for a vehicle power transmission device of the second invention, the dust cover has an arc-shaped main body and a pair of mounting parts that protrude radially from both ends of the main body, and is composed of two parts that have the same shape as each other, so there is no misassembly and the number of parts and assembly man-hours are reduced.

[0014] According to the dust cover for a vehicle power transmission device of the third invention, the power transmission shaft has a large-diameter portion that is relatively larger in diameter than the shaft portion of the power transmission shaft, located opposite the inner circumferential surface of the gearbox opening, and the dust cover has an inner circumferential portion having an inner circumferential edge with a smaller diameter than the large-diameter portion, and the axial distance between the inner circumferential portion and the large-diameter portion is smaller than the distance between the inner circumferential surface of the gearbox opening and the outer circumferential surface of the large-diameter portion. This makes it possible to sufficiently secure a labyrinth seal structure of a narrow maze, and the intrusion of foreign matter can be suitably suppressed.

[0015] According to the dust cover for a vehicle power transmission device of the fourth invention, the oil seal is fitted to the inner circumferential surface of the opening of the gearbox. The oil seal comprises an annular oil seal body fitted to the inner circumferential surface of the opening of the gearbox, a first lip portion and a second lip portion that protrude annularly inward from the oil seal body portion and slide in contact with two locations on the large diameter portion of the power transmission shaft, and a contact portion that protrudes from the oil seal body portion toward the dust cover and abuts against the back surface of the dust cover. As a result, lubricating oil such as grease can be contained in the space enclosed by the dust cover, the contact portion and the oil seal body portion, thereby increasing the durability of the oil seal. Furthermore, the first lip portion and the second lip portion that protrude annularly inward from the oil seal body portion and slide in contact with two locations on the large diameter portion of the power transmission shaft enhance the oiltightness on the bearing side. [Brief explanation of the drawing]

[0016] [Figure 1] This figure illustrates the schematic configuration of the main parts of a vehicle power transmission device to which the present invention is applied. [Figure 2] This is an enlarged view illustrating the seal structure of the power transmission shaft in Figure 1. [Figure 3]It is a perspective view explaining one of the two components constituting the dust cover of FIG. 2. [Figure 4] It is a side view explaining one of the two components constituting the dust cover of FIG. 2. [Figure 5] It is a perspective view explaining the dust cover of FIG. 2 assembled using two parts of the part in FIG. 3 or FIG. 4.

Mode for Carrying Out the Invention

[0017] The dust cover of the present invention may be a press part formed by pressing from a metal plate material, or may be a resin molded product formed by pressure-injecting a heated resin material with fluidity into a cavity in a molding die.

[0018] The dust cover of the present invention has a split structure composed of a plurality of parts, but the plurality of parts may be two parts or three or more parts. The plurality of parts preferably have the same shape as each other.

Example

[0019] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a view explaining a main part of a vehicle power transmission device 10 to which the present invention is applied. The power transmission shaft 12 in FIG. 2 transmits power from an output shaft of a transmission (not shown) arranged on the rear wheel side to a differential gear device arranged between a pair of rear wheels.

[0020] One end of the power transmission shaft 12 is connected via a joint 22 to a differential drive pinion 20, which is another rotating body rotatably supported by a pair of bearings 16, 18 by a differential housing 14. The joint 22 is formed in a cylindrical shape and is concentrically fastened by a nut 24 in a state of being fitted to the differential drive pinion 20 in a non-rotatable manner. At one end of the power transmission shaft 12, a flange portion 28 is integrally formed, which is fastened by a bolt 26 in a concentrically fitted state by an inlay structure with the joint 22. The flange portion 28 is formed to have a large diameter about 2.8 times the diameter of the shaft portion 12a of the power transmission shaft 12. An annular oil seal 30 for sealing the inside of the differential housing 14 in an oil-tight manner is provided between the differential housing 14 and the joint 22.

[0021] The other end of the power transmission shaft 12 is inserted into the gearbox 32 through a circular opening 34 formed in the gearbox 32, and is spline-fitted in a non-rotatable manner and axially movable with a central hole 42 of a gear 40 rotatably supported by bearings 36, 38. In the axial direction of the power transmission shaft 12, a gap S (≧D) allowing the movement of the power transmission shaft 12 by a fitting depth D is formed between the gear 40 and a large-diameter portion 44 described later.

[0022] A large-diameter portion 44, which is relatively larger in diameter than the shaft portion 12a of the power transmission shaft 12, is formed on the portion of the power transmission shaft 12 facing the inner circumferential surface of the opening 34. An annular oil seal 46 is fitted into the opening 34, and the space between the inner circumferential surface of the opening 34 and the outer circumferential surface of the large-diameter portion 44 is sealed oil-tightly to suppress oil leakage. As shown in detail in Figure 2, an annular dust cover 48 having an L-shaped inner circumferential portion 48b with an inner circumferential edge 48a smaller in diameter than the large-diameter portion 44 is fixed to the gearbox 32 by bolts 50 so as to cover the oil seal 46 when the power transmission shaft 12 is assembled. A labyrinth seal structure is formed by a radial passage PA formed by the axial distance A between the inner circumferential portion 48b and the large-diameter portion 44, and an axial passage PB formed by the radial distance B between the inner circumferential portion 48b and the large-diameter portion 44. The axial distance A and radial distance B are sufficiently smaller than the distance C between the inner circumferential surface of the opening 34 of the gearbox 32 and the outer circumferential surface of the large diameter portion 44.

[0023] The oil seal 46 is press-fitted to the inner circumferential surface of the opening 34 of the gearbox 32. The oil seal 46 comprises an annular oil seal body portion 46a fitted to the inner circumferential surface of the opening 34 of the gearbox 32, a first lip portion 46b and a second lip portion 46c that protrude annularly inward from the oil seal body portion 46a and slide against two locations on the large diameter portion 44 of the power transmission shaft 12, and a contact portion 46d that protrudes from the oil seal body portion 46a toward the dust cover 48 and abuts against the back surface of the dust cover 48. Lubricating oil such as grease is contained in the space 52 closed by the dust cover 48, the contact portion 46d and the oil seal body portion 46a. Furthermore, the oiltightness on the bearing 36 side is enhanced by the first lip portion 46b and the second lip portion 46c, which protrude annularly from the oil seal body portion 46a toward the inner circumference and slide in contact with two locations on the large diameter portion 44 of the power transmission shaft 12.

[0024] The dust cover 48 has a segmented structure composed of multiple arc-shaped parts (in this embodiment, two parts 54, 54 having the same arc shape to each other). Figure 3 is a perspective view showing the arc-shaped part 54, and Figure 4 is a side view of the arc-shaped part 54 as seen from the center of curvature of the arc.

[0025] The arc-shaped component 54 has an arc-shaped main body 56 having a flange-like outer circumference 56a, a first L-shaped section 56b, and a second L-shaped section 56c, and a pair of upper mounting portions 58 and lower mounting portions 60 protruding radially from both ends of the main body 56. The lower mounting portion 60 has a mounting hole 60a and is formed to be horizontal at one end of the arc-shaped component 54 (the right end in Figure 4) via a neck portion 60b that rises from the outer circumference 56a.

[0026] The other end (left end in Figure 4) of the arc-shaped part 54 has an overlapping portion 62 that overlaps onto one end of the other part 54. The overlapping portion 62 bulges out in the axial direction of the power transmission shaft 12 by the thickness of one plate. The upper mounting portion 58 has a mounting hole 58a and is formed to be horizontal at the other end (left end in Figure 4) of the arc-shaped part 54 via a neck portion 58b that rises from the flat end surface of the first stage portion 56b of the overlapping portion 62. The upper mounting portion 58 and the lower mounting portion 60 are formed to overlap each other when the two parts 54, 54, which are all the same arc shape, are combined in an annular shape, and are fastened together with a bolt 50.

[0027] Figure 5 shows a dust cover 48 formed by combining two parts 54, 54, which have the same arc shape as described above, in an annular shape. The annular dust cover 48 having the aforementioned inner circumference 48b corresponds to the second stage portion 56c formed on the arc-shaped main body portion 56 of part 54.

[0028] When assembling the power transmission shaft 12 configured as described above, due to the spigot structure between the flange portion 28 and the joint 22, it is necessary to move the power transmission shaft 12 toward the gearbox 32 by the fitting depth D of the spigot structure, then fit the flange portion 28 with the joint 22, and then fasten the two together with bolts 26. For this reason, when fixing the dust cover 48 to the power transmission shaft 12, it is necessary to position the dust cover 48 in a position that avoids interference with the gearbox 32, and it was not possible to sufficiently secure the labyrinth seal structure formed by the dust cover 48.

[0029] In contrast, the dust cover 48 of the vehicle power transmission device 10 in this embodiment has a split structure, so it can be fixed to the gearbox 32 after the power transmission shaft 12 has been assembled. Therefore, it is not necessary to fix the dust cover 48 to the power transmission shaft 12 in a position that avoids interference with the bearing 36 and the gearbox 32 that houses the oil seal 46, which are provided at the other end of the power transmission shaft 12. This ensures that the labyrinth structure formed by the dust cover 48 is sufficiently secured, and the intrusion of foreign matter can be effectively suppressed.

[0030] Furthermore, according to the dust cover 48 of the vehicle power transmission device 10 of this embodiment, the dust cover 48 has an arc-shaped main body portion 56 and a pair of upper mounting portions 58 and lower mounting portions 60 that protrude radially from both ends of the main body portion 56, and is composed of two parts 54, 54 that have the same shape as each other, so there is no misassembly and the number of parts and assembly man-hours are reduced.

[0031] Furthermore, according to the dust cover 48 of the vehicle power transmission device 10 of this embodiment, the power transmission shaft 12 has a large-diameter portion 44 that is relatively larger in diameter than the shaft portion 12a of the power transmission shaft 12, located opposite the inner circumferential surface of the opening 34 of the gearbox 32, and the dust cover 48 has an inner circumferential portion 48b that is smaller in diameter than the large-diameter portion 44, and the axial distance A between the inner circumferential portion 48b and the large-diameter portion 44 is smaller than the distance C between the inner circumferential surface of the opening 34 of the gearbox 32 and the outer circumferential surface of the large-diameter portion 44. As a result, a labyrinth seal structure of a narrow maze can be sufficiently secured, and the intrusion of foreign matter can be suitably suppressed.

[0032] Furthermore, according to the dust cover 48 of the vehicle power transmission device 10 of this embodiment, the oil seal 46 is fitted to the inner circumferential surface of the opening 34 of the gearbox 32. The oil seal 46 comprises an annular oil seal body portion 46a fitted to the inner circumferential surface of the opening 34 of the gearbox 32, a first lip portion 46b and a second lip portion 46c that protrude annularly inward from the oil seal body portion 46a and slide against two locations on the large diameter portion 44 of the power transmission shaft 12, and a contact portion 46d that protrudes from the oil seal body portion 46a toward the dust cover 48 and abuts against the back surface of the dust cover 48. As a result, lubricating oil such as grease can be contained in the annular space 52 closed by the dust cover 48, the contact portion 46d and the oil seal body portion 46a, thereby increasing the durability of the oil seal 46. Furthermore, the first lip portion 46b and the second lip portion 46c, which protrude annularly inward from the oil seal body portion 46a and slide in contact with two locations on the large diameter portion 44 of the power transmission shaft 12, enhance the oiltightness on the bearing 36 side.

[0033] Although embodiments of the present invention have been described in detail above with reference to the drawings, these are merely examples, and the invention can be implemented in various modified and improved forms. [Explanation of symbols]

[0034] 10: Vehicle power transmission device, 12: Power transmission shaft, 12a: Shaft section, 22: Coupling, 32: Gearbox, 34: Opening, 36: Bearing, 44: Large diameter section, 46: Oil seal, 46a: Oil seal body section, 46b: First lip section, 46c: Second lip section, 46d: Contact section, 48: Dust cover, 48a: Inner periphery, 48b: Inner periphery section, 54: Part, 56: Main body section, 58: Upper mounting section (mounting section), 60: Lower mounting section (mounting section), A: Axial spacing, B: Radial spacing, C: Spacing, PA: Radial passage, PB: Axial passage

Claims

1. A dust cover for a vehicle power transmission device, in which one end is connected to another rotating body via a joint with an interlocking structure, the other end is rotatably supported by a bearing housed in a gearbox, and oil leakage between the opening of the gearbox and the power transmission shaft is suppressed by an oil seal, The dust cover is composed of multiple parts divided into an arc shape, forming an annular shape, and is fixed to the gearbox so as to cover the opening of the gearbox when the power transmission shaft is assembled. A dust cover for a vehicle power transmission device, characterized by the following features.

2. The dust cover is composed of two parts, each having an arc-shaped main body and a pair of mounting parts that protrude radially from both ends of the main body, and both parts having the same shape. A dust cover for a vehicle power transmission device according to characteristic 1.

3. The power transmission shaft has a large-diameter portion that is relatively larger in diameter than the shaft portion of the power transmission shaft, at a position facing the inner circumferential surface of the opening of the gearbox. The dust cover has an inner circumferential portion having an inner circumferential edge with a smaller diameter than the large diameter portion. A labyrinth seal structure is formed by a radial passage between the inner circumference and the large diameter portion having an axial spacing smaller than the distance between the inner surface of the gearbox opening and the outer surface of the large diameter portion, and an axial passage between the inner circumference and the large diameter portion having a radial spacing smaller than the distance between the inner surface of the gearbox opening and the outer surface of the large diameter portion. A dust cover for a vehicle power transmission device according to characteristic 1.

4. The oil seal is fitted to the inner circumferential surface of the opening of the gearbox. The oil seal comprises an annular oil seal body fitted to the inner circumferential surface of the opening of the gearbox, a first lip portion and a second lip portion that protrude annularly inward from the oil seal body portion and slide against two locations on the large diameter portion of the power transmission shaft, and a contact portion that protrudes from the oil seal body portion toward the dust cover and abuts against the back surface of the dust cover. A dust cover for a vehicle power transmission device according to feature 3.

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