Propeller shaft

Abstract

To provide a propeller shaft capable of suppressing intrusion of muddy water, etc. into the inside of a center bearing as much as possible.SOLUTION: At a position on an opening-portion side of a holding ring 26 of a propeller shaft, a stub shaft 8 in this case, a water-impermeable cover 30, which is provided with an opening portion extending so as to approach the opening portion of the holding ring 26 is provided. According to this, the water-impermeable cover 30 is fixed in a position on the opening-portion side of the holding ring 26 of the stub shaft 8, and the opening portion of the water-impermeable cover 30 is extended so as to approach the opening portion of the holding ring 26, therefore, even if muddy water, etc. scatters obliquely from the opening-portion side of the holding ring 26, risk of muddy water, etc. entering the opening portion of the holding ring 26 is suppressed, and as a result, phenomenon of muddy water, etc. entering the inside of a center bearing 19 can be made less likely to occur.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a propeller shaft for an automobile, and more particularly to a propeller shaft supported on a vehicle body via a center bearing. [Background technology]

[0002] A known example of a propeller shaft support device that is attached to the underside of an automobile body and elastically supports a center bearing attached to the propeller shaft is described in JP 2016-124422 A (Patent Document 1).

[0003] The propeller shaft support device of Patent Document 1 comprises an annular elastic support member having a cross section bent into an approximately U-shape, an outer ring which is integrally vulcanization bonded to the outer peripheral end of the elastic support member, an inner ring which is integrally vulcanization bonded to the inner peripheral part of the elastic support member and is press-fitted into the outer ring of a center bearing, and a retaining ring which is fitted inside the inner ring to be integrated with the inner ring and which restricts the outer ring of the center bearing from moving in the axial direction.

[0004] The outer ring of this centre bearing support device is fitted into a bracket on the underside of the vehicle body, and the inner ring is fitted onto the outer ring of the centre bearing which is attached to the outer circumference of the propeller shaft. This elastically supports the centre bearing on the underside of the vehicle body via an elastic support member made of a rubber-like elastic material, and this elastic support member absorbs and cushions vibrations between the propeller shaft and the vehicle body while the vehicle is in motion. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2016-124422 A Summary of the Invention [Problem to be solved by the invention]

[0006] Incidentally, the propeller shaft support device described in Patent Document 1 has an end face of a dust cover that extends toward the inside of a pressure ring that rotates together with the propeller shaft portion inserted into the "U"-shaped internal space of a pressure ring that is fixed to the inner circumference of an inner ring, forming a labyrinth seal between the inner wall of the pressure ring and the end face of the dust cover.

[0007] However, in Patent Document 1, although a labyrinth seal is formed, a gap is formed between the inner wall of the retaining ring and the end face of the dust cover, which may cause muddy water or the like that flies into the gap to enter the inside of the center bearing.

[0008] An object of the present invention is to provide a propeller shaft capable of minimizing the intrusion of muddy water and the like into the inside of a center bearing. [Means for solving the problem]

[0009] The present invention relates to In a propeller shaft that transmits the driving force of a power source, a shaft having a first end and a second end; a center bearing having an inner ring fixed to an outer circumferential surface of the shaft, rolling elements arranged on the outer periphery of the inner ring, and an outer ring arranged on the outer periphery of the rolling elements; an inner ring formed in a cylindrical shape so as to surround an outer peripheral surface of the shaft along a rotation axis of the shaft and hold an outer ring of a center bearing; a pressing ring disposed in an annular gap between an outer peripheral surface of the shaft and an inner peripheral surface of the inner ring, fixed to the inner peripheral surface of the inner ring when viewed along the rotation axis of the shaft, the pressing ring having a first annular region extending in a direction toward the center bearing along the shaft, a second annular region continuing from the first annular region extending in a direction toward the shaft, and a third annular region continuing from the second annular region extending in a direction opposite to the center bearing along the shaft; a dust cover arranged on the outer circumferential surface of the shaft on the opposite side of the retaining ring from the center bearing, and fixed to the outer circumferential surface of the shaft when viewed along the rotational axis of the shaft, the dust cover having a first cover area extending in a direction toward the retaining ring along the shaft, a second cover area continuing from the first cover area and extending in a direction away from the shaft, and a third cover area continuing from the second cover area and extending in a direction toward the retaining ring along the shaft; By combining the pressing ring and the dust cover, the third cover area of ​​the dust cover extends between the first and third annular areas of the pressing ring, and the third cover area of ​​the pressing ring extends between the first and third cover areas of the dust cover, The water-shielding cover has a first water-shielding area portion that is disposed on the outer circumferential surface of the shaft on the opposite side to the pressing ring across the dust cover, and is fixed to the outer circumferential surface of the shaft when viewed along the rotation axis of the shaft, a second water-shielding area portion that continues from the first water-shielding area portion and extends in a direction away from the shaft, and a third water-shielding area portion that continues from the second water-shielding area portion and extends in a direction along the shaft toward the dust cover, and covers a part of the second cover area portion and the third cover area portion of the dust cover from the outside. It is characterized by the following. Effect of the Invention

[0010] According to the present invention, the water-proof cover is fixed to a position on the open side of the pressure ring of the stub shaft so as to sandwich the dust cover, and the open part of the water-proof cover is extended so as to be close to the open part of the pressure ring. Therefore, even if muddy water or the like flies diagonally from the open part side of the pressure ring, the risk of the muddy water or the like entering the open part of the pressure ring is suppressed by the water-proof cover, and as a result, the phenomenon of muddy water or the like entering the inside of the center bearing is less likely to occur. [Brief description of the drawings]

[0011] [Figure 1] 1 is an external view showing the external appearance of a propeller shaft to which the present invention is applied; [Diagram 2] 2 is an enlarged cross-sectional view showing an enlarged cross-section of the vicinity of a support device for a propeller shaft shown in FIG. 1. [Diagram 3] 3 is an enlarged cross-sectional view showing a further enlarged cross-section of the vicinity of the support device for the propeller shaft shown in FIG. 2. [Figure 4] 1 is a cross-sectional view of a propeller shaft support device according to a first embodiment of the present invention and its surroundings. [Diagram 5] 5 is an enlarged cross-sectional view showing an enlarged cross-section of the vicinity of a support device for a propeller shaft shown in FIG. 4. [Figure 6] FIG. 4 is a cross-sectional view of the vicinity of a support device for a propeller shaft according to a second embodiment of the present invention. [Figure 7] FIG. 11 is a cross-sectional view of the vicinity of a support device for a propeller shaft according to a third embodiment of the present invention. [Figure 8] FIG. 11 is a cross-sectional view of the vicinity of a support device for a propeller shaft according to a fourth embodiment of the present invention. [Figure 9] FIG. 11 is a cross-sectional view of the vicinity of a support device for a propeller shaft according to a fifth embodiment of the present invention. [Figure 10] FIG. 13 is a cross-sectional view of the vicinity of a support device for a propeller shaft according to a sixth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following embodiment, and various modifications and application examples within the technical concept of the present invention are also included within its scope.

[0013] Before describing the present invention, the configuration of a propeller shaft on which the present invention is based will be described with reference to Figures 1 to 3. The propeller shaft described below has already been proposed by the present applicant.

[0014] As shown in FIG. 1, the propeller shaft to which the present invention is applied is used in automobiles that use a four-wheel drive or front-engine, rear-drive drive system, and is mainly composed of a drive shaft 1 connected to a transmission coupled to a power source such as an internal combustion engine, a driven shaft 2 connected to a differential gear, a constant velocity joint 3 connecting the drive shaft 1 and the driven shaft 2, and a support device 5 provided on the constant velocity joint 3 side of the drive shaft 1 and fixed to the lower part of a floor member of the automobile, for example, a cross member 4.

[0015] The drive shaft 1 is composed of a steel drive side tube 6, a Cardan joint 7 fixed axially to the front end of the drive side tube 6 by welding, and a stub shaft 8 fixed axially to the rear end of the drive side tube 6 by welding.

[0016] The driven shaft 2 is mainly composed of a steel pipe, a constant velocity joint casing 10 that is axially fixed to the front end of the driven tube 9 by welding and through which the end of the stub shaft 8 is inserted, and a Cardan joint 11 that is axially fixed to the rear end of the driven tube 9 by welding.

[0017] As shown in Figs. 2 and 3, the stub shaft 8 is made of an iron-based metal and formed in a stepped diameter shape. The stub shaft 8 has a stub large diameter portion 8a fixed to the rear end of the drive side tube 6, a stub medium diameter portion 8b and a stub small diameter portion 8c which are gradually formed in smaller diameters in the axial direction.

[0018] Between the stub large diameter portion 8a and the stub medium diameter portion 8b, there is formed a stub second large diameter step 8d which is smaller in diameter than the stub large diameter portion 8a but larger in diameter than the stub medium diameter portion 8b, and between this stub second large diameter step 8d and the stub medium diameter portion 8b, there is formed a stub medium diameter step 8e which is smaller in diameter than the stub second large diameter step 8d but larger in diameter than the stub medium diameter portion 8b, and a step surface 8f is formed between the stub medium diameter step 8e and the stub medium diameter portion 8b. Also, an inner race 12 of the constant velocity joint 3, which will be described later, is fixed to the outer periphery of the extended tip of the stub small diameter portion 8c.

[0019] As shown in FIG. 2, the constant velocity joint 3 is mainly composed of a constant velocity joint casing 10 which is an outer race formed in a substantially cylindrical shape and which is fixed to the front end of the driven shaft 2, the inner race 12 which is arranged on the inner periphery of the constant velocity joint casing 10, a plurality of torque transmission balls 13 which are provided so as to be able to roll between the constant velocity joint casing 10 and the inner race 12, and a cage 14 which holds these torque transmission balls 13.

[0020] As shown in FIG. 2, the constant velocity joint casing 10 has a plurality of grooves 10a formed axially on its inner peripheral side at approximately equally spaced positions in the circumferential direction, and the inner race 12, which faces the inner peripheral side of the constant velocity joint casing 10, has a plurality of recesses 12a formed axially on its outer peripheral side at approximately equally spaced positions in the circumferential direction corresponding to the grooves 10a.

[0021] The inside of the constant velocity joint 3 is filled with lubricating oil such as grease, and a rubber boot 15 that seals the inside of the constant velocity joint casing 10 is attached to the front end side of the constant velocity joint casing 10.

[0022] The boot 15 is made of rubber and formed into a stepped cylindrical shape, and is composed of a main body 15a fitted onto the outer periphery of the tip end of the constant velocity joint casing 10, and a folded-back portion 15c formed by folding back from a tip end 15b of the main body 15a toward the inner periphery, the tip of which is fitted onto the outer periphery of the stub small diameter portion 8c of the stub shaft 8. A core material 15d is embedded inside the main body 15a.

[0023] As shown in Figures 2 and 3, the support device 5 is mainly composed of a mounting bracket 16 which is an annular member attached to the cross member 4 of the vehicle body, an elastic member 17 fixed to the inside of this mounting bracket 16, a metal inner ring 18 which is a support member fixed to the inner side of this elastic member 17, and a center bearing 19 held inside this inner ring 18.

[0024] The inner ring 18 is formed in a cylindrical shape surrounding the outer periphery of the stub shaft 8 along the rotation axis of the stub shaft 8 that constitutes the shaft. In other words, the stub shaft 8 passes through the inside of the inner ring 18, forming an annular gap between the inner peripheral surface of the inner ring 18 and the outer peripheral surface of the stub shaft 8. A center bearing 19 and a pressing ring 26 are housed in this annular gap.

[0025] The elastic member 17 is made of rubber and has a horizontal U-shaped cross section that opens toward the front of the vehicle body. Its outer peripheral surface is vulcanization bonded to the inner peripheral surface of a metallic annular press-fit fixing portion 20 that is press-fitted and fixed to the inner peripheral surface of the mounting bracket 16, and its inner peripheral surface is vulcanization bonded to the outer peripheral surface of the inner ring 18.

[0026] The inner ring 18 is made of a thin metal plate formed into a cylindrical shape with a stepped diameter, and is composed of a large diameter annular portion 18a formed on the outer circumferential side of the stub medium diameter step portion 8e of the stub shaft 8, a medium diameter annular portion 18b formed continuously from this large diameter annular portion 18a and provided on the outer circumferential side of the stub medium diameter portion 8b, and a small diameter annular portion 18c formed continuously from this medium diameter annular portion 18b.

[0027] The center bearing 19 includes an inner ring 21 press-fitted onto the outer periphery of the stub medium diameter portion 8b of the stub shaft 8, an outer ring 22 held on the inner periphery of the medium diameter annular portion 18b of the inner ring 18, and a plurality of steel balls 23 rollably held between an arc-shaped retaining groove formed in the center of the opposing surfaces of the inner ring 21 and the outer ring 22. In addition, annular oil seals 24, 25 are attached to both ends in the width direction of the inner ring 21 and the outer ring 22.

[0028] A pressing ring 26 that opens toward the front side of the vehicle body is press-fitted and fixed to the inner peripheral side of the large diameter annular portion 18a of the inner ring 18. Meanwhile, a dust cover 27 is press-fitted and fixed to the stub second large diameter step 8d of the stub shaft 8 located on the vehicle body front side of the pressing ring 26, and the other end portion extends into the open interior of the pressing ring 26. In addition, an annular seal member 28 that is formed in an annular shape from a rubber material and has a core material embedded therein is provided between the inner peripheral surface of the pressing ring 26 and the outer peripheral surface of the stub medium diameter step 8e.

[0029] Therefore, the presser ring 26 is disposed so as to surround the other end of the dust cover 27, and the path of infiltration of muddy water, etc. into the outer circumferential surface of the stub medium diameter step 8e of the stub shaft 8 is complicated, thereby forming a so-called labyrinth seal, which inhibits infiltration of muddy water, etc. into the outer circumferential surface of the stub medium diameter step 8e of the stub shaft 8. Furthermore, an annular seal member 28 is disposed between the inner circumferential surface of the presser ring 26 and the outer circumferential surface of the stub medium diameter step 8e, thereby preventing infiltration of muddy water, etc. into the interior of the center bearing 19 from the front of the vehicle.

[0030] A retaining member 29 is provided which is press-fitted onto the outer periphery of the stub medium diameter portion 8b of the stub shaft 8 to axially position and fix the center bearing 19. As shown in Fig. 3, the retaining member 29 is formed by pressing a thin metal plate into a substantially U-shaped cross section, and is composed of one end 29a press-fitted onto the outer periphery of the stub medium diameter portion 8b, and the other end 29b extending radially from the rear end edge of the one end 29a and bent back towards the center bearing 19.

[0031] The one end 29a is formed in a substantially cylindrical shape, and the tip portion 2 on the center bearing 19 side is 9c is bent and formed in an expanded diameter shape, and a tip edge 29d of this tip portion 29c abuts against one side surface 21a of the inner ring 21 of the center bearing 19 in the axial direction to hold the inner ring 21 in a sandwiched state together with the stepped surface 8f. Therefore, the inner ring 21 of the center bearing 19 is fixed in the axial direction, so that the entire structure can be firmly held.

[0032] The other end 29b is composed of a bent portion 29e bent radially outward and a cylindrical portion 29f extending from the outer peripheral edge of the bent portion 29e toward the outer ring 22 of the center bearing 19, and the bent portion 29e and the cylindrical portion 29f surround the small diameter portion 18c of the inner ring 18 to shield the inside of the center bearing 19.

[0033] In other words, the other end 29b of the retaining member 29 surrounds the outer periphery of the small diameter annular portion 18c of the inner ring 18, thereby complicating the path of infiltration into the inside of the center bearing 19 and forming a so-called labyrinth seal. This makes it possible to prevent muddy water and the like from infiltrating into the inside of the center bearing 19 from the rear side of the inner ring 18 on the vehicle body.

[0034] Furthermore, since the labyrinth seal can prevent muddy water from entering from the rear of the vehicle body, it is also possible to eliminate the need for annular sealing member between the small-diameter annular portion 18c of the inner ring 18 and the retaining portion 29b, which prevents muddy water and the like from entering the inside of the center bearing 19.

[0035] In a propeller shaft configured as described above, the retaining ring 26 is positioned to surround the other end of the dust cover 27 to form a labyrinth seal, but a gap is formed between the inner wall of the retaining ring 26 and the other end of the dust cover 27, which means that muddy water or the like flying toward this gap may enter the inside of the center bearing 19.

[0036] In other words, when muddy water or the like flies at a high speed diagonally toward the open portion of the pressure ring 26 in Figure 2, the muddy water or the like will enter the inside of the center bearing through the gap formed between the inner wall of the pressure ring 26 and the other end of the dust cover 27. EXAMPLES

[0037] Therefore, this embodiment is characterized in that a watertight cover having an opening extending close to the open portion of the retaining ring is provided at a position sandwiching the dust cover on the open portion side of the retaining ring of the propeller shaft, in this case the stub shaft.

[0038] In this way, the water-proof cover is fixed to a position on the open side of the pressure ring of the stub shaft, and the open part of the water-proof cover is extended so that it is close enough to the open part of the pressure ring but does not come into contact with it. Therefore, even if muddy water or the like flies diagonally toward the open part of the pressure ring, the water-proof cover reduces the risk of the muddy water or the like entering through the open part of the pressure ring, and as a result, the phenomenon of muddy water or the like entering the inside of the center bearing is less likely to occur.

[0039] The first embodiment of the present invention will be described in detail below with reference to FIGS. 4 and 5. In the drawings, reference numbers are given to parts closely related to this embodiment, and reference numbers are not given to other parts not closely related to this embodiment. For these, please refer to the descriptions in Figures 2 and 3. Here, Figure 4 shows the configuration of a support part for a propeller shaft, and Figure 5 shows an enlarged portion thereof.

[0040] In Figures 4 and 5, when cross-sectioned on a plane parallel to the rotation axis of the stub shaft 8, the retaining ring 26 is formed from three regions, namely, a first annular region 26a, a second annular region 26b continuing from the first annular region 26a, and a third annular region 26c continuing from the second annular region 26b.

[0041] The first annular area portion 26a is pressed into and fixed to the large diameter annular portion 18a of the inner ring 18, the second annular area portion 26b extends toward the stub shaft 8 and prevents the outer ring 23 of the center bearing 19 from moving to the left side in the drawing, i.e., toward the dust cover 27, and the third annular area portion 26c extends toward the opposite side to the center bearing 19 and prevents the annular seal member 28 from moving in the radial and axial directions.

[0042] Here, the first annular area 26a, the second annular area 26b, and the third annular area 26c are formed to have a substantially U-shaped cross section, and an open portion is formed by the first annular area 26a and the third annular area 26c along the rotation axis of the stub shaft 8. The first annular area 26a and the third annular area 26c extend toward the opposite side to the center bearing 19.

[0043] The dust cover 27 is formed of three areas, namely, a first cover area 27a, a second cover area 27b continuing from the first cover area 27a, and a third cover area 27c continuing from the second cover area 27b. The dust cover 27 is disposed on the opposite side of the center bearing 19 with the pressing ring 26 as a boundary.

[0044] The first cover area portion 27a is press-fitted and fixed into the stub second large diameter step portion 8d of the stub shaft 8, the second cover area portion 27b extends radially outward relative to the rotation axis of the stub shaft 8, and the third cover area portion 27c is formed so as to gradually expand (the outer diameter gradually increases) in the radial direction away from the rotation axis of the stub shaft 8.

[0045] Here, the first cover area portion 27a, the second cover area portion 27b, and the third cover area portion 27c are formed to have a substantially U-shaped cross section, and an open portion is formed by the first cover area portion 27a and the third cover area portion 27c along the rotation axis of the stub shaft 8. The first cover area portion 27a and the third cover area portion 27c extend toward the center bearing 19 side.

[0046] Therefore, as shown in FIG. 4, the openings of the pressing ring 26 and the dust cover 27 face each other, and the third annular area 26c and the third cover area 27c extend into the spaces of the respective openings.

[0047] That is, the open portion of the pressing ring 26 (formed by the first annular area portion 26a and the third annular area portion 26c) and the open portion of the dust cover 27 (formed by the first cover area portion 27a and the third cover area portion 27c) are arranged to face each other.

[0048] By combining the pressing ring 26 and the dust cover 27, the third cover area 27c of the dust cover 27 extends into the space between the first annular area 26a and the third annular area 26c which form the open portion of the pressing ring 26. As a result, a labyrinth is formed between the second annular area 26b of the pressing ring 26 and the tip 27t of the third cover area 27c of the dust cover 27.

[0049] Similarly, the third annular region 26c of the pressing ring 26 extends into the space between the first cover region 27a and the third cover region 27c which form the opening of the dust cover 27. This forms a labyrinth between the second cover region 27b of the dust cover 27 and the tip 26t of the third annular region 26c of the pressing ring 26.

[0050] As described above, the first cover area 27a of the dust cover 27 is bent toward the pressing ring 26 and fixed to the stub shaft 8, as compared with that shown in Fig. 2. This makes it possible to shorten the length in the direction of the rotation axis.

[0051] As shown in FIG. 5, the vicinity of the tip 27t of the third cover area 27c of the dust cover 27 is bent outward in a radial direction perpendicular to the rotation axis, preventing muddy water flowing through the third cover area 27c from changing direction and flowing into the gap between the second annular area 26b of the pressure ring 26 and the tip 27t of the third cover area 27c of the dust cover 27.

[0052] Similarly, the vicinity of the tip 26t of the third annular area 26c of the pressure ring 26 is bent outward in a radial direction perpendicular to the rotation axis, preventing muddy water flowing through the third annular area 26c from changing direction and flowing into the gap between the second cover area 27b of the dust cover 27 and the tip 26t of the third annular area 26c of the pressure ring 26.

[0053] Next, the water shielding cover 30, which is a feature of this embodiment, will be described. The water shielding cover 30 is The dust cover 27 is disposed on the opposite side of the retaining ring 26 and is fixed to the stub shaft 8 at a position sandwiching the dust cover 27. The water-blocking dust cover 30 is formed of three regions, namely, a first water-blocking region 30a, a second water-blocking region 30b continuing from the first water-blocking region 30a, and a third water-blocking region 30c continuing from the second water-blocking region 30b.

[0054] The first watertight region 30a is fixed to the stub first large diameter step 8g of the stub shaft 8, the second watertight region 30b extends radially outward relative to the rotation axis of the stub shaft 8, and the third watertight region 30c is formed so as to gradually expand (the outer diameter gradually increases) in the radial direction away from the rotation axis of the stub shaft 8.

[0055] Here, an opening is formed by the third water-impermeable region 30c and the outer surface of the stub shaft 8. The second cover region 27b of the dust cover 27 and a part of the third cover region 27C are housed in this opening while overlapping in the direction of the rotation axis, and as a result, the third water-impermeable region 30c is configured to cover the second cover region 27b of the dust cover 27 and a part of the third cover region 27C from the outside.

[0056] Furthermore, as shown in Figure 5, when viewed in a direction perpendicular to the rotation axis of the stub shaft 8, the third water-blocking area 30c is located outside the third cover area 27c of the dust cover 27, and the end face of the third water-blocking area 30c is close to the end face of the first annular area 26a of the pressure ring 26 and faces it via a gap (g).

[0057] Therefore, the third water-blocking region 30c overlaps with the third cover region 27c when viewed from the rotation axis of the stub shaft 8. This gap (g) is determined to be shorter than the gap (G) formed by the tip 27t of the third cover region 27c of the dust cover 27 and the second annular region 26b of the pressing ring 26. Here, as can be seen from Fig. 5, the dust cover 27 is covered from the outside by both the pressing ring 26 and the water-blocking cover 30.

[0058] Furthermore, the gap (g) is set to a length shorter than the axial length (Ls) of the third water-shielding region 30c of the water-shielding cover 30. This allows the dust cover 27 to be covered while reducing the area of ​​the path for muddy water to enter, thereby reducing the risk of muddy water entering through the opening of the retaining ring 26.

[0059] In this way, the water-blocking cover 30 is positioned to cover the dust cover 27 from the outside, so that even if muddy water or the like flies diagonally toward the open portion of the pressure ring 26, the water-blocking cover 30 reduces the risk of the muddy water or the like entering through the open portion of the pressure ring 26, and as a result, it is possible to make it less likely for muddy water or the like to enter the inside of the center bearing.

[0060] Next, another characteristic configuration of this embodiment will be described with reference to FIG.

[0061] First, in the third water-shielding region 30c of the water-shielding cover 30, the maximum outer diameter (Ds) of the third water-shielding region 30c overlapping with the third cover region 27c as viewed in the direction of the rotation axis of the stub shaft 8 is set to be equal to or smaller than the maximum outer diameter (Dr) of the large-diameter annular portion 18a of the inner ring 18, in other words, the length is set not to exceed the maximum outer diameter (Dr) of the large-diameter annular portion 18a of the inner ring 18. This prevents the water-shielding cover 30 from getting in the way when the stub shaft 8 is welded to the drive-side tube 6.

[0062] Further, as viewed in the direction of the rotation axis of the stub shaft 8, in the third water-shielding region 30c of the water-shielding cover 30, the maximum outer diameter (Ds) of the third water-shielding region 30c is set to be smaller than the maximum outer diameter (Dr) of the large-diameter annular portion 18a of the inner ring 18 and larger than the maximum outer diameter (Dd) of the dust cover 26. This makes it possible to suppress the intrusion of muddy water.

[0063] Additionally, as viewed in the direction of the rotation axis of the stub shaft 8, the third water-blocking region 30c of the water-blocking cover 30 is designed so that the outer diameter gradually increases toward the center bearing 19. This makes it easier for muddy water to be discharged by centrifugal force when it enters the water-blocking cover 30.

[0064] Furthermore, for the same reason, the outside diameter of the third cover region 27c of the dust cover 27 is designed to gradually increase as it approaches the center bearing 19 when viewed in the direction of the rotation axis of the stub shaft 8.

[0065] Further, a tip portion 27t is newly formed in the third cover region 27c of the dust cover 27, which extends (curves outward) radially outward in a direction perpendicular to the rotation axis of the stub shaft 8. This prevents muddy water flowing in the third annular region 26c from changing direction and flowing into the gap between the second annular region 26b of the pressing ring 26 and the tip portion 27t of the third cover region 27c of the dust cover 27.

[0066] Moreover, the water-shielding cover 30 has a first water-shielding region 30a extending to the opposite side to the dust cover 27 and fixed to the stub shaft 8, and a third water-shielding region 30c extending to the dust cover 27 side, and has a cross-sectional shape that is substantially inverted "Z" shape in the drawings. The third water-shielding region 30c of the water-shielding cover 30 can be overlapped with the third cover region 27c of the dust cover 27 using a small amount of material.

[0067] In addition, in the dust cover 27, the first cover area 27a is fixed to the stub shaft 8, but the first cover area 27a and the third cover area 27c extend toward the pressing ring 26 and have a substantially U-shaped cross section. This allows the axial length of the stub shaft 8 to be shortened.

[0068] Further, the stub shaft 8 is provided with a step portion that abuts against the radial surface of the water-shielding cover 30 when the water-shielding cover 30 is attached, so as to extend in the radial direction by the stub first large diameter step portion 8g of the stub shaft 8. This allows the water-shielding cover 30 to be reliably positioned and fixed.

[0069] Furthermore, the stub shaft 8 is formed with a stub first large diameter step 8g and a stub second large diameter step 8d having a smaller diameter than the stub first large diameter step 8g, with a water impermeable cover 30 fixed to the stub second large diameter step 8d, and a dust cover 27 fixed to the stub second large diameter step 8d. Since a step is formed between the stub first large diameter step 8g and the stub second large diameter step 8d, the dust cover 27 can be reliably positioned and fixed.

[0070] In addition, in the retaining ring 26, the third annular region 26c radially presses the annular seal member 28 arranged on the outer periphery of the stub shaft 8, thereby restricting movement of the tubular seal member 28 and improving sealing performance. EXAMPLES

[0071] Next, a second embodiment of the present invention will be described with reference to Fig. 6. This embodiment is characterized in that the shape of the tip of the third water-shielding region 31c of the water-shielding cover 31 is changed. Note that the same components as those shown in Figs. 4 and 5 are given the same reference numerals, and the description thereof will be omitted.

[0072] In Figure 6, as shown in Figure 5, a tip portion 27t is formed at the tip of the third cover area portion 27c of the dust cover 27, extending outward in a direction perpendicular to the rotation axis of the stub shaft 8, and similarly, a tip portion 31t is formed at the tip of the third water-blocking area portion 31c of the water-blocking cover 31, extending outward in a direction perpendicular to the rotation axis of the stub shaft 8.

[0073] Even if muddy water or the like flies obliquely toward the open portion of the pressure ring 26, the direction of movement of the muddy water is changed to the radial direction by the tip portion 31t of the third water-blocking region 31c of the water-blocking cover 31. This reduces the risk of muddy water or the like entering through the open portion of the pressure ring 26, and as a result, it is possible to make it difficult for the phenomenon of muddy water or the like entering the inside of the center bearing to occur. EXAMPLES

[0074] Next, a third embodiment of the present invention will be described with reference to Fig. 7. This embodiment is characterized in that the maximum outer diameter of the third water-blocking region 32c of the water-blocking cover 31 is made larger than the maximum outer diameter of the large-diameter annular portion 18a of the inner ring 18. Note that the same components as those shown in Figs. 4 and 5 are given the same reference numerals, and descriptions thereof will be omitted.

[0075] In Figure 7, when viewed in the direction of the rotation axis of the stub shaft 8, in the third water-shielding area 32c of the water-shielding cover 32, the maximum outer diameter (Ds) of the third water-shielding area 32c that overlaps with the third cover area 27c is set to be equal to or larger than the maximum outer diameter (Dr) of the large diameter annular portion 18a of the inner ring 18, in other words, to a length that exceeds the maximum outer diameter (Dr) of the large diameter annular portion 18a of the inner ring 18.

[0076] Furthermore, even if muddy water or the like flies diagonally toward the open portion of the pressure ring 26, the third water-blocking area 32c of the water-blocking cover 32 covers the dust bar 27 from the outside, thereby reducing the risk of muddy water or the like entering through the open portion of the pressure ring 26. As a result, it is possible to make it less likely for muddy water or the like to enter the inside of the center bearing. EXAMPLES

[0077] Next, a fourth embodiment of the present invention will be described with reference to Fig. 8. This embodiment is characterized in that the maximum outer diameter of the third water-blocking region 33c of the water-blocking cover 33 is made larger than the maximum outer diameter of the large-diameter annular portion 18a of the inner ring 18, and the third water-blocking region 33c extends to the large-diameter annular portion 18a of the inner ring 18. Note that the same components as those shown in Figs. 4 and 5 are given the same reference numerals, and description thereof will be omitted.

[0078] In Figure 8, when viewed in the direction of the rotation axis of the stub shaft 8, in the third water-shielding area 33c of the water-shielding cover 33, the maximum outer diameter (Ds) of the third water-shielding area 33c that overlaps with the third cover area 27c is set to be equal to or larger than the maximum outer diameter (Dr) of the large diameter annular portion 18a of the inner ring 18, in other words, to a length that exceeds the maximum outer diameter (Dr) of the large diameter annular portion 18a of the inner ring 18.

[0079] Furthermore, the third water-blocking region 33c extends toward the center bearing 19 beyond the end face of the large-diameter annular portion 18a of the inner ring 18 and the end face of the first annular region 26a of the pressing ring 26. In other words, an overlapping region (OL) is formed between the tip of the third water-blocking region 33c and the end face of the large-diameter annular portion 18a of the inner ring 18 and the end face of the first annular region 26a of the pressing ring 26.

[0080] Furthermore, even if muddy water or the like flies diagonally toward the open portion of the pressure ring 26, the third water-blocking area 33c of the water-blocking cover 33 covers it from the outside, beyond the end face of the large diameter annular portion 18a of the inner ring 18 and the first annular area 26a of the pressure ring 26, thereby reducing the risk of muddy water or the like entering through the open portion of the pressure ring 26. As a result, it is possible to make it less likely for muddy water or the like to enter the inside of the center bearing. EXAMPLES

[0081] Next, a fifth embodiment of the present invention will be described with reference to Fig. 9. This embodiment is characterized in that the first water-blocking region 34a of the water-blocking cover 34 is formed toward the pressing ring 26. Note that the same components as those shown in Figs. 4 and 5 are given the same reference numerals, and description thereof will be omitted.

[0082] In the above-described embodiment, the water-blocking covers 30-33 have first water-blocking areas 30a-33a extending opposite the pressure ring 26 and fixed to the stub shaft 8, and third water-blocking areas 30c-33c extending toward the pressure ring 26, so that the cross-sectional shape is approximately an inverted "Z" shape in the drawings.

[0083] 9, in the present embodiment, in the water-shielding cover 34, the first water-shielding region 34a is fixed to the stub shaft 8, but the first water-shielding region 34a and the third water-shielding region 34c both extend toward the pressing ring 26 and have a substantially U-shaped cross section. This allows the axial length of the stub shaft 8 to be shortened. EXAMPLES

[0084] Next, a sixth embodiment of the present invention will be described with reference to Fig. 10. This embodiment is characterized in that the water-shielding cover 35 is disposed away from the pressing ring 26, and a gap is formed between the tip of the third water-shielding area 35c of the water-shielding cover 35 and the end face of the second cover area 27b of the dust cover 27 on the water-shielding cover 35 side, so that the water-shielding cover 35 and the dust cover 27 do not overlap each other. Note that the same components as those shown in Figs. 4 and 5 are denoted by the same reference numerals, and description thereof will be omitted.

[0085] In the above-described embodiment, the water-blocking covers 30 to 34 are configured to have an area overlapping with the dust cover 27 when viewed along the rotation axis of the stub shaft 8.

[0086] In contrast, in the present embodiment, the water-shielding cover 35 is positioned away from the dust cover 27, thereby forming a gap (OD) between the tip of the third water-shielding area 35c of the water-shielding cover 35 and the end face of the second cover area 27b of the dust cover 27 on the water-shielding cover 35 side, thereby preventing the water-shielding cover 35 and the dust cover 27 from overlapping.

[0087] That is, the third waterproof region 30c extends along the stub shaft 8 in the direction toward the dust cover 27, and further extends to just before reaching the second cover region 27b of the dust cover 27. Here, the tip of the third waterproof region 30c is close to and faces the end face of the first annular region 26a of the pressing ring 26. Here, the gap (OD) is set to a length shorter than the gap (g) shown in FIG. 5. Also, the end face of the first annular region 26a of the pressing ring 26 and the end face of the second cover region 26b of the dust cover 27 are at approximately the same position when viewed along the rotation axis of the stub shaft 8.

[0088] The third water-shielding region 35c of the water-shielding cover 35 has the same shape as the third water-shielding region 31c of the water-shielding cover 31 shown in Fig. 6. That is, when viewed from the rotation axis line of the stub shaft 8, the end face of the third water-shielding region 35c extends radially outward and is warped outward.

[0089] Moreover, the first water-shielding region 35a of the water-shielding cover 35 has the shape of the first water-shielding region 34a of the water-shielding cover 34 shown in Fig. 9. That is, when viewed from the rotation axis line of the stub shaft 8, the first water-shielding region 35a and the third water-shielding region 35c both extend toward the pressing ring 26, and have a substantially "U" shaped cross section.

[0090] In this way, even if the water-shielding cover 35 and the dust cover 27 do not overlap when viewed in the direction of the rotation axis of the stub shaft 8, the water-shielding cover 35 is configured to cover the open portion of the pressure ring 26 from the outside. Therefore, even if muddy water or the like flies diagonally toward the open portion of the pressure ring 26, the water-shielding cover 35 suppresses the risk of the muddy water or the like entering through the open portion of the pressure ring 26. As a result, it is possible to make it less likely that muddy water or the like will enter the inside of the center bearing.

[0091] As described above, the present invention is configured such that a waterproof cover having an opening that extends close to the open portion of the pressure ring is provided at a position on the open portion side of the pressure ring of the propeller shaft, separate from the dust cover.

[0092] According to this, the water-proof cover is fixed to a position on the open side of the pressure ring of the stub shaft and the open part of the water-proof cover is extended so as to be close to the open part of the pressure ring. Therefore, even if muddy water or the like flies diagonally from the open part side of the pressure ring, the water-proof cover reduces the risk of the muddy water or the like entering through the open part of the pressure ring, and as a result, the phenomenon of muddy water or the like entering the inside of the center bearing is less likely to occur.

[0093] The features of the claims other than claim 1 are as follows. ≪Claim 2≫ In the propeller shaft according to claim 1, A propeller shaft, characterized in that the maximum outer diameter of the third water-proof area of ​​the water-proof cover is determined to be equal to or smaller than the maximum outer diameter of the inner ring. ≪Claim 3≫ In the propeller shaft according to claim 2, A propeller shaft, characterized in that an outer diameter of the third water-shielding area of ​​the water-shielding cover is set to be smaller than a maximum outer diameter of the inner ring and larger than a maximum outer diameter of the dust cover. ≪Claim 4≫ In the propeller shaft according to claim 1, A propeller shaft, characterized in that the third water-proof area of ​​the water-proof cover has a shape that gradually expands in a direction away from the rotation axis of the shaft. ≪Claim 5≫ In the propeller shaft according to claim 1, A propeller shaft, wherein the third cover area of ​​the dust cover has a shape that gradually widens in a direction away from the rotation axis of the shaft. ≪Claim 6≫ In the propeller shaft according to claim 1, A propeller shaft, wherein the water-impermeable cover has a first water-impermeable area extending on a side opposite to the dust cover, and a third water-impermeable area extending on a side of the dust cover. ≪Claim 7≫ In the propeller shaft according to claim 1, A propeller shaft, wherein the dust cover has the first cover area and the third cover area extending toward the retaining ring. ≪Claim 8≫ In the propeller shaft according to claim 1, A propeller shaft characterized in that the shaft is formed with a stepped portion that abuts against a radial surface of the water-blocking cover. ≪Claim 9≫ In the propeller shaft according to claim 1, A propeller shaft characterized in that the shaft has a first outer diameter portion to which the water-proof cover is fixed and a second outer diameter portion having a smaller diameter than the first outer diameter portion to which the center bearing is fixed, and the dust cover is fixed to the portion between the first outer diameter portion and the second outer diameter portion. ≪Claim 10≫ In the propeller shaft according to claim 1, A propeller shaft, comprising: an annular seal member disposed on the third annular region of the pressing ring and on the outer circumferential surface of the shaft. ≪Claim 11≫ In the propeller shaft according to claim 1, A propeller shaft characterized in that a tip of the third cover area of ​​the dust cover and / or a tip of the third water-resistant area of ​​the water-resistant cover extend outward in a direction perpendicular to the rotation axis of the shaft. ≪Claim 12≫ In the propeller shaft according to claim 1, A propeller shaft, characterized in that the maximum outer diameter of the third water-proof area of ​​the water-proof cover is determined to be equal to or larger than the maximum outer diameter of the inner ring. ≪Claim 13≫ In the propeller shaft according to claim 1, A propeller shaft characterized in that the maximum outer diameter of the third water-shielding area of ​​the water-shielding cover is determined to be larger than the maximum outer diameter of the inner ring, and further, the third water-shielding area extends so as to cover the dust cover and a portion of the inner ring from the outside. ≪Claim 14≫ In the propeller shaft according to claim 1, A propeller shaft, wherein the water-impermeable cover is characterized in that the first water-impermeable area portion and the third water-impermeable area portion extend toward the dust cover. ≪Claim 15≫ In a propeller shaft that transmits the driving force of a power source, a shaft having a first end and a second end; a center bearing including an inner ring fixed to an outer circumferential surface of the shaft, rolling elements arranged on the outer periphery of the inner ring, and an outer ring arranged on the outer periphery of the rolling elements; an inner ring formed in a cylindrical shape so as to surround the outer circumferential surface of the shaft along a rotation axis of the shaft and to hold the outer ring of the center bearing; a pressing ring disposed in an annular gap between the outer circumferential surface of the shaft and the inner circumferential surface of the inner ring, and fixed to the inner circumferential surface of the inner ring when viewed along the rotation axis of the shaft, the pressing ring having a first annular region extending in a direction toward the center bearing along the shaft, a second annular region continuing from the first annular region extending in a direction toward the shaft, and a third annular region continuing from the second annular region extending in a direction away from the center bearing along the shaft; a dust cover arranged on the outer circumferential surface of the shaft on the opposite side of the center bearing with respect to the pressing ring, and fixed to the outer circumferential surface of the shaft when viewed along the rotation axis of the shaft, the dust cover having a first cover area extending in a direction toward the pressing ring along the shaft, a second cover area continuing from the first cover area and extending in a direction away from the shaft, and a third cover area continuing from the second cover area and extending in a direction toward the pressing ring along the shaft; By combining the pressing ring and the dust cover, the third cover area of ​​the dust cover extends between the first and third annular areas of the pressing ring, and the third cover area of ​​the pressing ring extends between the first and third cover areas of the dust cover, a water-shielding cover including a first water-shielding area portion that is disposed on the outer circumferential surface of the shaft on the opposite side of the dust cover to the pressing ring, and that is fixed to the outer circumferential surface of the shaft when viewed along the rotation axis of the shaft, a second water-shielding area portion that continues from the first water-shielding area portion and extends in a direction away from the shaft, and a third water-shielding area portion that continues from the second water-shielding area portion and extends along the shaft in a direction toward the dust cover, and that covers a part of the second cover area portion and the third cover area portion of the dust cover from the outside, Furthermore, as viewed in the direction of the rotation axis of the shaft, a length between a tip of the first annular region of the pressing ring facing a tip of the third water-shielding region of the water-shielding cover and a tip of the third water-shielding region is determined to be shorter than a length of the third water-shielding region of the water-shielding cover. A propeller shaft comprising: ≪Claim 16≫ The propeller shaft according to claim 15, A propeller shaft characterized in that a tip of the third cover area of ​​the dust cover and / or a tip of the third water-resistant area of ​​the water-resistant cover extend outward in a direction perpendicular to the rotation axis of the shaft. ≪Claim 17≫ In a propeller shaft that transmits the driving force of a power source, a shaft having a first end and a second end; a center bearing including an inner ring fixed to an outer circumferential surface of the shaft, rolling elements arranged on the outer periphery of the inner ring, and an outer ring arranged on the outer periphery of the rolling elements; an inner ring formed in a cylindrical shape so as to surround the outer circumferential surface of the shaft along a rotation axis of the shaft and to hold the outer ring of the center bearing; a pressing ring disposed in an annular gap between the outer circumferential surface of the shaft and the inner circumferential surface of the inner ring, and fixed to the inner circumferential surface of the inner ring when viewed along the rotation axis of the shaft, the pressing ring having a first annular region extending in a direction toward the center bearing along the shaft, a second annular region continuing from the first annular region extending in a direction toward the shaft, and a third annular region continuing from the second annular region extending in a direction away from the center bearing along the shaft; a dust cover arranged on the outer circumferential surface of the shaft on the opposite side of the center bearing with respect to the pressing ring, and fixed to the outer circumferential surface of the shaft when viewed along the rotation axis of the shaft, the dust cover having a first cover area extending in a direction toward the pressing ring along the shaft, a second cover area continuing from the first cover area and extending in a direction away from the shaft, and a third cover area continuing from the second cover area and extending in a direction toward the pressing ring along the shaft; By combining the pressing ring and the dust cover, the third cover area of ​​the dust cover extends between the first and third annular areas of the pressing ring, and the third cover area of ​​the pressing ring extends between the first and third cover areas of the dust cover, a water-shielding cover that is disposed on the outer circumferential surface of the shaft on the opposite side of the dust cover to the pressing ring, and is fixed to the outer circumferential surface of the shaft when viewed along the rotation axis of the shaft, and has a first water-shielding area that extends along the shaft, a second water-shielding area that continues from the first water-shielding area and extends in a direction away from the shaft, and a third water-shielding area that continues from the second water-shielding area and extends in a direction along the shaft toward the dust cover, up to just before reaching the second cover area of ​​the dust cover; A propeller shaft comprising: ≪Claim 18≫ The propeller shaft according to claim 17, A propeller shaft, characterized in that a maximum outer diameter of the third water-impermeable area of ​​the water-impermeable cover is set to be larger than a maximum outer diameter of the third cover area of ​​the dust cover.

[0094] The present invention is not limited to the above-mentioned embodiments, but includes various modified examples. The above-mentioned embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those having all the configurations described. In addition, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. It is also possible to add, delete, or replace other configurations with respect to the configuration of each embodiment. [Explanation of symbols]

[0095] 1...drive shaft, 2...driven shaft, 3...constant velocity joint, 4...support device, 6...driving side tube, 7...Cardan joint, 8...stub shaft, 9...driven side tube, 3...constant velocity joint, 4...support device, 6...driving side tube, 7...Cardan joint, 18...inner ring, 18a...large diameter annular portion, 19...center bearing, 26...pressing ring, 26a...first annular area, 26b...second annular area, 26c...third annular area, 27...dust cover, 27a...first cover area, 27b...second cover area, 27c...third cover area, 30-35...waterproof cover, 30a-35a...first waterproof area, 30b-35b...second waterproof area, 30c-35c...third waterproof area.

Claims

1. In a propeller shaft that transmits the driving force of a power source, A shaft, an annular bearing including an inner ring fixed to an outer circumferential surface of the shaft and an outer ring with rolling elements disposed between the inner ring and the outer ring; an inner ring supported by the outer ring of the bearing, having a cylindrical portion extending in a longitudinal direction of the shaft on one side of the bearing, and forming an annular gap between an inner peripheral surface of the cylindrical portion and the outer peripheral surface of the shaft; a presser ring disposed in the gap, one end of which is fixed to the inner circumferential surface of the cylindrical portion and the other end of which is an annular region extending in a direction away from the bearing in the longitudinal direction of the shaft; a dust cover having one end fixed to the outer circumferential surface of the shaft and the other end serving as a cover area extending into the annular area of ​​the pressing ring; a water-shielding cover having one end fixed to the outer circumferential surface of the shaft and the other end extending in the longitudinal direction of the shaft toward the annular region of the pressing ring and serving as a water-shielding region facing an opening formed between the annular region of the pressing ring and the cover region of the dust cover; The end faces of the waterproof cover and the pressing ring are opposed to each other and are close to each other with a gap of a predetermined length. A propeller shaft comprising:

2. 2. The propeller shaft according to claim 1, The water-shielding cover has a first region on one end side, a second region extending radially outward with respect to the rotation axis of the shaft, and a third region extending toward the pressing ring in the longitudinal direction of the shaft, and the water-shielding region includes the third region. A propeller shaft comprising:

3. 2. The propeller shaft according to claim 1, The water-shielding cover has a first region on one end side, a second region extending radially outward with respect to the rotation axis of the shaft, and a third region extending toward the pressing ring in the longitudinal direction of the shaft, and the water-shielding region includes the second region. A propeller shaft comprising:

4. The propeller shaft according to any one of claims 1 to 3, The water-shielding cover is formed so as to cover a part of the dust cover from the outside. A propeller shaft comprising:

Images