Intermediate shaft

Abstract

To provide an intermediate shaft enabling smooth telescopic operation to be performed and keeps water from entering from an outer space into an internal space of a female shaft.SOLUTION: An intermediate shaft 6 includes: a female shaft 10; a male shaft 11; and a seal ring 12 blocking an end part opening on an axial rear side of a clearance present between an inner peripheral surface of a cylinder part 13 of the female shaft 10 and an outer peripheral surface of the male shaft 11. The male shaft 11 has an axial hole 26 and a lateral hole 27. The axial hole 26 extends in an axial direction at a radial center part of the male shaft 11 and is open only in an end surface on the axial front side out of the end surfaces on opposite axial sides of the male shaft 11. The lateral hole 27 has an outer opening part that is always open in a portion positioned on the axial rear side relative to a seal ring 12 during use, and an inner opening part that is open in an inner peripheral surface of the axial hole 26, on a peripheral surface of the male shaft 11.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an intermediate shaft that constitutes a steering device. [Background technology]

[0002] A steering device for an automobile includes an intermediate shaft that connects the front end of a steering shaft, the rear end of which is fixed to a steering wheel, to a pinion shaft that constitutes a steering gear unit. A telescopic intermediate shaft, whose overall length can be extended or retracted, may be used as the intermediate shaft. By extending or retracting its overall length, a telescopic intermediate shaft can absorb impact in the event of a collision, absorb relative displacement between the vehicle body and the subframe in a vehicle in which the steering gear unit is mounted on a subframe, and facilitate assembly work into the vehicle.

[0003] The telescopic intermediate shaft, for example, when assembled to a vehicle, includes a tubular portion that passes through a panel that separates the interior and exterior of the vehicle cabin and is arranged so that it slopes downward as it approaches the front, a female shaft that has a bottom that closes the axially front end opening of the tubular portion, a male shaft whose axially front portion is inserted inside the tubular portion and whose outer peripheral surface engages with the inner peripheral surface of the tubular portion directly or via another member to enable torque transmission and relative axial displacement, and a seal ring that is supported on the axially rear end of the tubular portion and closes the axially rear end opening of a gap that exists between the inner peripheral surface of the tubular portion and the outer peripheral surface of the male shaft.

[0004] In an intermediate shaft of this structure, if the internal space of the female shaft is a completely sealed space, when the intermediate shaft extends or retracts, i.e., when the male shaft and the female shaft are displaced relative to each other in the axial direction, the change in air pressure in the internal space of the female shaft becomes large, hindering the extension and retraction of the intermediate shaft. Therefore, in order to avoid this inconvenience, it is conceivable to provide, for example, an air circulation path that connects the internal space of the female shaft with the external space, and by allowing air to pass between the internal space of the female shaft and the external space through this circulation path when the intermediate shaft extends or retracts, thereby minimizing the change in air pressure in the internal space of the female shaft.

[0005] As a specific example, Japanese Patent Application Laid-Open No. 2003-226244 (Patent Document 1) describes an intermediate shaft that has an axial hole penetrating in the axial direction at the radial center of a male shaft, and a yoke that constitutes a universal joint fixed to the axially upper end of the male shaft, the yoke having a through hole penetrating in the axial direction at a position aligned with the axial hole. In such an intermediate shaft, the axial hole and the through hole serve as an air flow path that communicates between the internal space of the female shaft and the external space, i.e., the space inside the vehicle cabin, allowing the intermediate shaft to smoothly extend and retract. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-226244 Summary of the Invention [Problem to be solved by the invention]

[0007] For example, in the case of a large vehicle such as a pickup truck, the interior of the vehicle may be washed with water. If water enters the internal space of the female shaft through the air flow path when the interior of the vehicle is washed with water, the entered water may impede the smooth extension and retraction of the intermediate shaft.

[0008] In this regard, in the structure described in JP 2003-226244 A (Patent Document 1), the upper end of the through hole provided in the yoke opens into the internal space of the yoke, which has a U-shaped cross section. Therefore, if water accumulates in the internal space of the yoke when washing the vehicle interior with water, the accumulated water may enter the inside of the through hole and further pass through the axial hole of the male shaft and enter the internal space of the female shaft.

[0009] An object of the present invention is to provide an intermediate shaft that can perform smooth extension and contraction movements and that makes it difficult for water to enter the internal space of the female shaft from the external space. [Means for solving the problem]

[0010] An intermediate shaft according to one aspect of the present invention includes a female shaft, a male shaft, and a seal ring.

[0011] When assembled to the vehicle, the female shaft has a cylindrical tube portion that passes through a panel that separates the interior and exterior of the vehicle and is arranged so as to incline downward as it approaches the front, and a bottom portion that closes the axially front end opening of the tube portion.

[0012] The axial front portion of the male shaft is inserted into the inside of the cylindrical portion, and the outer peripheral surface of the axial front portion engages with the inner peripheral surface of the cylindrical portion directly or via another member to enable torque transmission and relative axial displacement.

[0013] The seal ring is supported on the axially rear end of the cylindrical portion and closes the axially rear end opening of the gap that exists between the inner peripheral surface of the cylindrical portion and the outer peripheral surface of the male shaft.

[0014] The male shaft has an axial bore and a transverse bore.

[0015] The axial hole extends in the axial direction at the radial center of the male shaft, and is open only to the axially front end face of both axial end faces of the male shaft.

[0016] The horizontal hole has an outer opening that opens to a portion of the outer peripheral surface of the male shaft that is always axially rearward of the seal ring during use, and an inner opening that opens to the inner peripheral surface of the axial hole.

[0017] In the intermediate shaft according to one aspect of the present invention, the inner diameter of the lateral hole is smaller than the inner diameter of the axial hole.

[0018] In one aspect of the intermediate shaft of the present invention, the outer opening of the horizontal hole opens to a portion of the outer peripheral surface of the male shaft that is always axially rearward of the seal ring, even during assembly of the intermediate shaft into a vehicle.

[0019] In one aspect of the intermediate shaft of the present invention, when the intermediate shaft is assembled to a vehicle and a steering angle is applied to the steering wheel when the vehicle is traveling straight, the horizontal hole is arranged in a lower circumferential portion of the male shaft.

[0020] In one embodiment of the intermediate shaft of the present invention, when the intermediate shaft is assembled to a vehicle and a steering angle is applied to the steering wheel when the vehicle is traveling straight, the horizontal hole is arranged in the upper circumferential portion of the male shaft, and the central axis of the horizontal hole is arranged in a horizontal direction or in a direction that moves downward as it moves toward the front.

[0021] In one aspect of the intermediate shaft of the present invention, the male shaft includes a plurality of the transverse holes, and in this case, the transverse holes can be arranged at a plurality of locations with different phases in the axial and / or circumferential directions of the male shaft. [Effects of the Invention]

[0022] According to the intermediate shaft of one aspect of the present invention, smooth extension and contraction can be performed, and water is less likely to enter the internal space of the female shaft from the external space. [Brief explanation of the drawings]

[0023] [Figure 1]FIG. 1 is a partial cross-sectional side view of a steering device equipped with an intermediate shaft according to a first embodiment of the present invention. [Figure 2] FIG. 2 is an enlarged view of part A in FIG. 1, with the panel and hole cover cut away. [Figure 3] FIG. 3 is an enlarged view of part A in FIG. 1, with a part of the intermediate shaft cut away and the panel and hole cover omitted. [Figure 4] FIG. 4 is an enlarged view of the axially intermediate portion of FIG. [Figure 5] FIG. 5 is a diagram corresponding to FIG. 3 and showing a second embodiment of the present invention. [Figure 6] FIG. 6 is an enlarged view of the axially intermediate portion of FIG. [Figure 7] FIG. 7 is a diagram corresponding to FIG. 3 and showing a third embodiment of the present invention. [Figure 8] FIG. 8 is an enlarged view of the axially intermediate portion of FIG. [Figure 9] FIG. 9 is a diagram corresponding to FIG. 8 and shows a fourth embodiment of the present invention. [Figure 10] FIG. 10 is a diagram corresponding to FIG. 8 and shows a fifth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0024] [Example 1] A first embodiment of the present invention will be described with reference to FIGS. 1 to 4. FIG.

[0025] The intermediate shaft 6 of this example constitutes a part of a steering device 1 mounted on a large vehicle such as a pickup truck. However, the intermediate shaft of the present invention can also constitute a part of a steering device mounted on a medium-sized or small vehicle.

[0026] The steering device 1 of this example includes a steering wheel 2, a steering shaft 3, a steering column 4, two universal joints 5a and 5b, an intermediate shaft 6, an extension shaft 7, and a steering gear unit 8.

[0027] In the following description, the front-rear direction and the up-down direction of the steering device 1 refer to the front-rear direction and the up-down direction of the vehicle on which the steering device 1 is mounted. With respect to the steering device 1, the front side is the left side in FIG. 1, and the rear side is the right side in FIG. 1.

[0028] The steering wheel 2, which is rotated by the driver, is attached to the rear end of a steering shaft 3. The steering shaft 3 is rotatably supported inside a steering column 4, which is supported on the vehicle body. The front end of the steering shaft 3 is connected to a pinion shaft 9 of a steering gear unit 8 via a universal joint 5a, an intermediate shaft 6, an extension shaft 7, and another universal joint 5b. Therefore, when the driver rotates the steering wheel 2, the rotation of the steering wheel 2 is transmitted to the pinion shaft 9 of the steering gear unit 8. The rotation of the pinion shaft 9 is converted into linear motion of a rack shaft meshed with the pinion shaft 9. As a result, a steering angle corresponding to the amount of rotation of the steering wheel 2 is applied to the left and right steered wheels.

[0029] The intermediate shaft 6 is configured so that its entire length can be extended or contracted, and includes a female shaft 10, a male shaft 11, and a seal ring 12, as shown in FIGS.

[0030] The female shaft 10 has a cylindrical portion 13 and a bottom portion 14 .

[0031] The tubular portion 13 is cylindrical and, when assembled to the vehicle, passes through a panel 17 that separates a vehicle interior 15 from an exterior 16 of the vehicle, and is arranged so as to incline downward as it approaches the front. That is, in this example, the panel 17 has a through hole 18. In this example, the tubular portion 13 is arranged so as to pass through the through hole 18 in a direction that approaches downward as it approaches the front. In this example, a hole cover 19 is assembled between the outer peripheral surface of the axial rear portion of the tubular portion 13 and the inner peripheral surface of the through hole 18, thereby closing the gap between the outer peripheral surface of the axial rear portion of the tubular portion 13 and the inner peripheral surface of the through hole 18.

[0032] The bottom portion 14 closes the axial front end opening of the cylindrical portion 13. In other words, the female shaft 10 is configured as a bottomed cylinder whose axial front end is closed and whose axial rear end is open.

[0033] In this example, the female shaft 10 further has a connecting shaft portion 20 that extends axially forward from the radial center of the axially front end face of the bottom portion 14. The connecting shaft portion 20 is a portion that connects to the axially rear end portion of the extension shaft 7 so as to enable torque transmission. The axial length of the connecting shaft portion 20 is sufficiently shorter than the axial length of the cylindrical portion 13.

[0034] The axial front portion of the male shaft 11 is inserted into the inside of the cylindrical portion 13, and the outer peripheral surface of the axial front portion is directly engaged with the inner peripheral surface of the cylindrical portion 13 to allow torque transmission and relative axial displacement. In other words, the male shaft 11 is combined with the female shaft 10 to allow torque transmission and relative axial displacement.

[0035] In this example, a female spline portion 21 provided on the inner peripheral surface of cylindrical portion 13 and a male spline portion 22 provided on the outer peripheral surface of the axially front end of male shaft 11 are spline-engaged. This enables torque transmission and axial relative displacement of male shaft 11 with respect to female shaft 10. In this example, lubricating grease is applied to the spline engagement portion between female spline portion 21 and male spline portion 22.

[0036] When carrying out the present invention, the outer peripheral surface of the axial front portion of the male shaft can be engaged with the inner peripheral surface of the cylindrical portion of the female shaft via another member to enable torque transmission and relative axial displacement. As such a configuration, for example, a configuration can be adopted in which a plurality of rolling elements such as balls or rollers, and a leaf spring or the like that applies a preload to the rolling elements, are arranged between female-side axial grooves that are provided at multiple locations in the circumferential direction on the inner peripheral surface of the cylindrical portion of the female shaft and male-side axial grooves that are provided at multiple locations in the circumferential direction on the outer peripheral surface of the axial front portion of the male shaft and extend in the axial direction.

[0037] In this example, the outer peripheral surfaces of the axially intermediate portion and rear end portion of male shaft 11 are configured as cylindrical surfaces whose outer diameter does not change in the axial direction. In this example, front yoke 23 that constitutes universal joint 5a is fixed by welding to the axially rear end portion of male shaft 11.

[0038] The seal ring 12 is supported on the axial rear end of the cylindrical portion 13 and closes the axial rear end opening of the gap that exists between the inner surface of the cylindrical portion 13 and the outer surface of the male shaft 11.

[0039] In this example, seal ring 12 comprises an annular core metal 24 having an L-shaped cross section that is fitted and fixed onto the rear end of tubular portion 13, and seal material 25 that is fixed to core metal 24 and has a tip end that is in sliding contact over the entire circumference with the outer circumferential surface of the axially intermediate portion of male shaft 11. Grease for lubrication is applied between the tip end of seal material 25 and the outer circumferential surface of the axially intermediate portion of male shaft 11.

[0040] In this example, the portion of female shaft 10 located rearward of panel 17, more specifically rearward of panel 17 and hole cover 19, male shaft 11, and seal ring 12 are disposed inside vehicle compartment 15. The portion of female shaft 10 located forward of panel 17, more specifically forward of panel 17 and hole cover 19, is disposed outside vehicle compartment 16.

[0041] In this example, the male shaft 11 further has an axial bore 26 and a transverse bore 27 .

[0042] The axial hole 26 extends in the axial direction at the radial center of the male shaft 11, and is open only to the axially front end face of the both axial end faces of the male shaft 11.

[0043] In this example, the axial hole 26 is configured as a stepped circular hole extending in the axial direction and provided only in the axially front half of the male shaft 11. That is, in this example, the axial hole 26 has, in order from the rear side, which is the deepest side in the axial direction, to the front side, which is the opening side in the axial direction, a small-diameter hole portion 30 which is the circular hole portion with the smallest inner diameter, a medium-diameter hole portion 31 which is a circular hole portion with an inner diameter larger than that of the small-diameter hole portion 30, and a large-diameter hole portion 32 which is a circular hole portion with an inner diameter larger than that of the medium-diameter hole portion 31. When carrying out the present invention, the axial hole of the male shaft can also be configured as a circular hole whose inner diameter does not change in the axial direction. In this example, the portion of the male shaft 11 located axially rearward of the axial hole 26, i.e., the axially rear half, is configured as a solid shaft.

[0044] The horizontal hole 27 has an outer opening 28 that opens at a portion of the outer peripheral surface of the male shaft 11 that is always located axially rearward of the seal ring 12 when the intermediate shaft 6 is in use, and an inner opening 29 that opens at the inner peripheral surface of the axial hole 26. That is, in this example, the axial hole 26 and the horizontal hole 27 serve as air circulation paths that communicate between the internal space of the female shaft 10 and the external space, i.e., the space inside the vehicle cabin 15, thereby enabling the intermediate shaft 6 to smoothly extend and retract.

[0045] In this example, horizontal hole 27 is configured as a circular hole that radially penetrates a portion of male shaft 11 between the outer peripheral surface of an axially intermediate portion of male shaft 11 and the inner peripheral surface of the axially rear end portion of small diameter hole portion 30, which is the axially rear end portion of axial hole 26. In other words, outer opening 28, which is the radially outer opening portion of horizontal hole 27, opens into the outer peripheral surface of the axially intermediate portion of male shaft 11. Inner opening 29, which is the radially inner opening portion of horizontal hole 27, opens into the inner circumferential surface of axial hole 26 at the axially rear end portion.

[0046] In this example, the outer opening 28 of the horizontal hole 27 is always located axially rearward of the seal ring 12 when the intermediate shaft 6 is in use. That is, in this example, even when the intermediate shaft 6 expands or contracts during use, that is, when the female shaft 10 and the male shaft 11 are relatively displaced in the axial direction, the axial position of the outer opening 28 of the horizontal hole 27 on the male shaft 11 is regulated so that the axial distance L between the outer opening 28 of the horizontal hole 27 and the seal ring 12 does not become less than 0; in other words, so that the outer opening 28 of the horizontal hole 27 does not enter the radially inner side of the seal ring 12.

[0047] Furthermore, in this example, the outer opening 28 of the horizontal hole 27 opens to a portion of the outer peripheral surface of the male shaft 11 that is always located axially rearward of the seal ring 12, even during the assembly of the intermediate shaft 6 to the vehicle. In other words, when the intermediate shaft 6 of this example is assembled to the vehicle, its overall length can be extended or contracted, that is, the female shaft 10 and the male shaft 11 can be relatively displaced in the axial direction, thereby facilitating the assembly to the vehicle. In this example, even when the female shaft 10 and the male shaft 11 are relatively displaced in the axial direction during the assembly of the intermediate shaft 6 to the vehicle, the axial position of the outer opening 28 of the horizontal hole 27 on the male shaft 11 is regulated so that the axial distance L between the outer opening 28 of the horizontal hole 27 and the seal ring 12 is not less than 0.

[0048] In this example, the inner diameter d of the horizontal hole 27 is smaller than the inner diameter of the axial hole 26, more specifically, smaller than the inner diameter D of the small diameter hole portion 30 of the axial hole 26 (d <D)。

[0049] When implementing the structure of this example, if the inner diameter d of the horizontal hole 27 is reduced, the surface tension of the water can effectively prevent water from entering the inside of the horizontal hole 27 through the outer opening 28 of the horizontal hole 27 when the vehicle interior 15 is washed with water. On the other hand, if the inner diameter d of the horizontal hole 27 is made too small, it becomes difficult to ensure sufficient breathability and ease of processing of the horizontal hole 27. Therefore, when implementing the structure of this example, it is preferable to determine the inner diameter d of the horizontal hole 27 by comprehensively considering these circumstances, that is, so that the surface tension of the water can effectively prevent water from entering the inside of the horizontal hole 27 through the outer opening 28 of the horizontal hole 27 and that the breathability and ease of processing of the horizontal hole 27 can be sufficiently ensured. From this perspective, the inner diameter d of the horizontal hole 27 is preferably set to, for example, 1 mm to 3 mm, and more preferably 1.5 mm to 2.5 mm.

[0050] In this example, when the intermediate shaft 6 is assembled to the vehicle and a steering angle is applied to the steering wheel when the vehicle is traveling straight, the horizontal hole 27 is disposed in an upper circumferential portion of the male shaft 11, as shown in Figures 3 and 4. However, when the present invention is implemented, when the intermediate shaft is assembled to the vehicle and a steering angle is applied to the steering wheel when the vehicle is traveling straight, the horizontal hole may also be disposed in a circumferential portion of the male shaft different from that in this example.

[0051] According to the structure of this example, the following effects can be achieved.

[0052] The axial hole 26 and the lateral hole 27 of the male shaft 11 serve as air circulation paths connecting the internal space of the female shaft 10 with the external space, i.e., the space inside the vehicle cabin 15, thereby enabling the intermediate shaft 6 to smoothly extend and retract.

[0053] The outer opening of the transverse hole 27 opens to the outer peripheral surface of the male shaft 11. That is, there is no part that forms a water pool like the conventional structure around the outer opening 28 of the transverse hole 27, specifically, a part like the inner space of a yoke having a U-shaped cross-sectional shape. Therefore, when the vehicle interior 15 is washed with water, it is difficult for water to enter the inside of the transverse hole 27 through the outer opening 28 of the transverse hole 27. The water washing operation of the vehicle interior 15 is usually performed with the steering wheel having the steering angle at the time of straight running of the vehicle applied thereto.

[0054] The inner diameter d of the transverse hole 27 is smaller than the inner diameter of the axial hole 26, and more specifically, smaller than the inner diameter D of the small-diameter hole portion 30 of the axial hole 26 (d < D). Therefore, the inner diameter d of the transverse hole 27 can be made sufficiently small, and as a result, when the vehicle interior 15 is washed with water, it is possible to effectively prevent water from entering the inside of the transverse hole 27 through the outer opening 28 of the transverse hole 27 by the surface tension of the water. Even if water enters the inner space of the female shaft 10 from the external space through the transverse hole 27 and the axial hole 26, the amount thereof can be extremely reduced because the inner diameter d of the transverse hole 27 is small. Further, the water that enters at this time moves to the inner space of the female shaft 10 from the opening on the front side of the axial hole 26 without passing through the spline engagement portion between the female spline portion 21 and the male spline portion 22, so that it is possible to prevent the sliding function of the spline engagement portion from deteriorating.

[0055] The axial hole 26 opens only to the front end surface in the axial direction among the end surfaces on both sides in the axial direction of the male shaft 11. That is, the axial hole 26 is provided only in a part of the male shaft 11 in the axial direction. Therefore, compared with the conventional structure in which the axial hole is provided over the entire length of the male shaft, the axial length of the axial hole can be shortened, and accordingly, the machining of the axial hole can be facilitated. Since the transverse hole 27 has a short axial length, it can be easily machined.

[0056] The outer opening 28 of the horizontal hole 27 opens at a portion of the outer peripheral surface of the male shaft 11 that is always located axially rearward of the seal ring 12 when the intermediate shaft 6 is in use or when it is assembled to the vehicle. This prevents the outer opening 28 of the horizontal hole 27 from entering the radially inner side of the seal ring 12 when the intermediate shaft 6 is in use or when it is assembled to the vehicle. This prevents the grease applied to the sealing material 25 of the seal ring 12 from entering the horizontal hole 27 and clogging it.

[0057] [Example 2] A second embodiment of the present invention will be described with reference to FIGS.

[0058] In this example, when the intermediate shaft 6 is assembled to the vehicle and a steering angle is applied to the steering wheel when the vehicle is traveling straight, the phase of the circumferential arrangement of the horizontal hole 27 provided in the male shaft 11 is different from that of Example 1. That is, in this example, when the intermediate shaft 6 is assembled to the vehicle and a steering angle is applied to the steering wheel when the vehicle is traveling straight, the horizontal hole 27 is arranged in a lower circumferential portion of the male shaft 11, as shown in Figures 5 and 6.

[0059] That is, in this example, when the intermediate shaft 6 is assembled to the vehicle and a steering angle for the vehicle traveling straight is applied to the steering wheel, the outer opening 28 of the horizontal hole 27 faces downward. Therefore, when the vehicle interior 15 (see FIG. 2) is flushed in this state, water is less likely to enter the inside of the horizontal hole 27 through the outer opening 28 of the horizontal hole 27. Furthermore, in this example, even if water enters the inside of the horizontal hole 27 through the outer opening 28 of the horizontal hole 27, the water that has entered the inside of the horizontal hole 27 can be discharged to the outside space through the outer opening 28 by the action of gravity. The other configurations, functions, and effects are the same as those of the first example.

[0060] [Example 3] A third embodiment of the present invention will be described with reference to FIGS.

[0061] In this example, when the intermediate shaft 6 is assembled to the vehicle and a steering angle is applied to the steering wheels when the vehicle is traveling straight, the horizontal hole 27a of the male shaft 11a is disposed in the upper circumferential portion of the male shaft 11a, as shown in Figures 7 and 8, similar to the first example. However, in this example, unlike the first example, the central axis of the horizontal hole 27a is disposed in the horizontal direction.

[0062] That is, in this example, when the intermediate shaft 6 is assembled to the vehicle and the steering wheel is steered at a steering angle for driving the vehicle straight, the outer opening 28 of the horizontal hole 27a faces horizontally forward. Therefore, when the vehicle interior 15 (see FIG. 2) is flushed in this state, water is less likely to enter the inside of the horizontal hole 27a through the outer opening 28 of the horizontal hole 27a. Furthermore, in this example, because the central axis of the horizontal hole 27a is arranged horizontally, even if water enters the inside of the horizontal hole 27a through the outer opening 28 of the horizontal hole 27a, the water that has entered the inside of the horizontal hole 27a is less likely to flow toward the inner opening 29 due to the action of gravity, i.e., to flow into the axial hole 26. The other configurations, functions, and effects are similar to those of the first example.

[0063] [Example 4] A fourth embodiment of the present invention will be described with reference to FIG.

[0064] In this example, when the intermediate shaft 6 is assembled to the vehicle and a steering angle is applied to the steering wheels when the vehicle is traveling straight, the horizontal hole 27b of the male shaft 11b is disposed in the upper circumferential portion of the male shaft 11b, as in the first example, as shown in Fig. 9. However, in this example, unlike the first example, the central axis of the horizontal hole 27b is disposed in a direction that moves downward as it moves forward.

[0065] That is, in this example, when the intermediate shaft 6 is assembled to the vehicle and the steering wheel is steered to a steering angle for the vehicle traveling straight ahead, the outer opening 28 of the horizontal hole 27b faces downward in the vertical direction. Therefore, when the vehicle interior 15 (see FIG. 2) is flushed in this state, water is less likely to enter the inside of the horizontal hole 27b through the outer opening 28 of the horizontal hole 27b. Furthermore, in this example, even if water enters the inside of the horizontal hole 27b through the outer opening 28 of the horizontal hole 27b, the water that has entered the inside of the horizontal hole 27b can be discharged to the outside space through the outer opening 28 by the action of gravity. The other configurations, functions, and effects are the same as those of the first example.

[0066] [Example 5] A fifth embodiment of the present invention will be described with reference to FIG.

[0067] In this example, male shaft 11c has a plurality of horizontal holes 27a. More specifically, male shaft 11c has horizontal holes 27a at a plurality of locations (two locations in the illustrated example) that are arranged at different phases in the axial direction.

[0068] In this example, male shaft 11c has a plurality of horizontal holes 27a. Therefore, in this example, even if the inner diameter of horizontal hole 27a is made smaller than in the third example (see FIG. 8) in which male shaft 11a has only one horizontal hole 27a, it is possible to ensure air permeability between the internal space and the external space of female shaft 10 that is equal to or better than that in the third example. In this way, in this example, the inner diameters of the plurality of horizontal holes 27a can be made smaller, which makes it possible to more sufficiently prevent water from entering these horizontal holes 27a and also makes it easier to ensure the strength of male shaft 11c.

[0069] When carrying out the present invention, it is also possible to employ a configuration in which the male shaft is provided with transverse holes at a plurality of locations whose arrangement phases in the circumferential direction are different, or a configuration in which the male shaft is provided with transverse holes at a plurality of locations whose arrangement phases in the axial direction are different, and at each of a plurality of locations whose arrangement phases in the circumferential direction are different. The other configurations and effects are the same as those of the third example.

[0070] When carrying out the present invention, the structures of the above-described embodiments can be combined as appropriate within the scope of not causing any contradiction.

[0071] Although different from the present invention, in an intermediate shaft assembled to a vehicle, the intermediate shaft includes a female shaft having a cylindrical tube portion that, when assembled to a vehicle, passes through a panel that separates the interior and exterior of the vehicle cabin and is arranged so as to incline downward as it extends forward, a bottom portion that closes the axially rear end opening of the tube portion, a male shaft whose axially rear portion is inserted inside the tube portion and whose outer peripheral surface is engaged with the inner peripheral surface of the tube portion directly or via another member to enable torque transmission and relative axial displacement, and a seal ring supported on the axially front end of the tube portion and that closes the axially front end opening of a gap that exists between the inner peripheral surface of the tube portion and the outer peripheral surface of the male shaft, if a hole that communicates the internal space of the female shaft with the external space, i.e., an air circulation path, is provided in the portion of the female shaft that is arranged inside the vehicle cabin, the intermediate shaft can be made to perform smooth extension and contraction. [Explanation of symbols]

[0072] 1 Steering device 2 steering wheels 3 Steering shaft 4 Steering column 5a, 5b universal joint 6 Intermediate shaft 7 Extension Shaft 8 Steering gear unit 9 Pinion shaft 10 female shaft 11, 11a, 11b, 11c male shaft 12 Seal ring 13 Cylinder part 14 Bottom 15 Inside the vehicle 16 Outside the vehicle 17 Panels 18 Through holes 19 Hole Cover 20 Connecting shaft 21 Female spline part 22 Male spline part 23 York 24 Core 25 Sealing material 26 Axial hole 27, 27a, 27b horizontal hole 28 Outer opening 29 Inner opening 30 Small diameter hole 31 Medium diameter hole 32 Large diameter hole

Claims

1. a female shaft having a cylindrical tube portion that, when assembled to a vehicle, passes through a panel that separates the interior and exterior of the vehicle and is inclined downward as it extends toward the front, and a bottom portion that closes an axially front end opening of the tube portion; a male shaft having an axial front portion inserted into the cylindrical portion, and an outer peripheral surface of the axial front portion engaging with an inner peripheral surface of the cylindrical portion directly or via another member to enable torque transmission and relative axial displacement; a seal ring supported on an axial rear end of the cylindrical portion and configured to close an axial rear end opening of a gap existing between an inner peripheral surface of the cylindrical portion and an outer peripheral surface of the male shaft, The male shaft has an axial bore and a transverse bore, the axial hole extends in the axial direction at a radial center of the male shaft, and is open only to an axially front end face among both axially opposite end faces of the male shaft, the horizontal hole has an outer opening that opens to a portion of the outer peripheral surface of the male shaft that is always located axially rearward of the seal ring during use, and an inner opening that opens to an inner peripheral surface of the axial hole. Intermediate shaft.

2. The intermediate shaft of claim 1 , wherein the inner diameter of the transverse bore is smaller than the inner diameter of the axial bore.

3. 3. The intermediate shaft according to claim 1, wherein the outer opening of the lateral hole is open to a portion of the outer peripheral surface of the male shaft that is always positioned axially rearward of the seal ring even during assembly of the intermediate shaft into a vehicle.

4. 4. The intermediate shaft according to claim 1, wherein the horizontal hole is disposed in a lower circumferential portion of the male shaft when the intermediate shaft is assembled to a vehicle and a steering angle is applied to a steering wheel when the vehicle is traveling straight.

5. 4. The intermediate shaft according to claim 1, wherein, when the intermediate shaft is assembled to a vehicle and a steering angle is applied to a steering wheel when the vehicle is traveling straight, the horizontal hole is disposed in an upper circumferential portion of the male shaft, and the central axis of the horizontal hole is disposed in a horizontal direction or in a direction that extends downward as it approaches the front.

6. The intermediate shaft according to any one of claims 1 to 5, wherein the male shaft has a plurality of the horizontal holes.

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