Steering device

Abstract

A steering device of the present invention is provided with an input side housing including an opening end surface through which a steering shaft passes. A step portion having a diameter stepwisely enlarged toward the opposite side of a steering wheel in the axial direction of the steering shaft is formed on the inner peripheral surface of the axial end portion on the opening end surface side of the input side housing. A ring-shaped dust seal is fitted into the step portion to seal the space between the inner peripheral surface of the input side housing and the outer peripheral surface of the steering shaft. A space in which water can accumulate exists between the steering shaft, the axial end portion of the input side housing, and the dust seal. A first groove, capable of discharging the water accumulated in the space, is formed in the axial end portion.

Description

DESCRIPTIONTITLE OF THE INVENTION: STEERING DEVICETECHNICAL FIELD

[0001] The present invention relates to a steering device.BACKGROUND TECHNOLOGY

[0002] JP 7003287 B (hereinafter is referred to as a patent document 1 ) discloses a steering device including a sheering shaft to which rotation force from a steering wheel is input, and a housing that has an opening end surface through which the steering shaft passes, and accommodates part of the steering shaft. A step portion having a diameter stepwisely enlarged toward the opposite side of the steering wheel in the axial direction of the steering shaft is formed on the inner peripheral surface of the axial end portion on the opening end surface side of the housing. In addition, a ring-shaped sealing member is disposed in the step part to seal the space between the inner peripheral surface of the housing and the outer peripheral surface of the steering shaft. A space is provided between the steering shaft, the axial end portion of the housing, and the sealing member.

[0003] In addition, a torque sensor for detecting the steering torque of the steering shaft is provided at a position vertically below the sealing member in the steering shaft.SUMMARY OF THE INVENTION

[0004] The steering device of the patent document 1 is generally mounted in the engine room. For example, when water enters the engine room due toreasons such as a turning wheel splashing up rainwater, this water may be accumulated in the space between the steering shaft, the axial end portion of the housing, and the sealing member. This water degrades the sealing member or corrodes the housing, and if it flows vertically below the sealing member, it reaches a torque sensor, which includes various electronic components, causing electronic component failure.

[0005] The present invention has been made into consideration of such a technical problem, and an object of the present invention is to provide a steering device capable of suppressing electronic component failure caused by water.

[0006] According to an embodiment, a steering device includes: a steering shaft to which rotational force from a steering wheel is input; a transmission mechanism for transmitting the rotational force of the steering shaft to a turning wheel; a torque sensor that is provided around the steering shaft and detects a steering torque of the steering shaft; a housing that has an opening end surface through which the steering shaft passes, accommodates a part of the steering shaft, and is formed, on an inner peripheral surface of an axial end portion on an opening end surface side thereof, with a step portion having a diameter stepwisely enlarged toward an opposite side of the steering wheel in the axial direction of the steering shaft; and a ring-shaped sealing member provided on the step portion to seal between an inner peripheral surface of the housing and an outer peripheral surface of the steering shaft, wherein a space is provided between the steering shaft, the axial end portion of the housing, and the sealing member, and wherein a drain is formed in a portion of the axial end portion of the housing that is positioned on a steering wheel side relative to the sealingmember, so as to communicate between the space and an outside of the housing to discharge water accumulated in the space.

[0007] According to the present invention, it is possible to suppress electronic component failure caused by water.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] FIG. 1 is a longitudinal sectional view of a steering device of a first embodiment.

[0009] FIG. 2 is an enlarged sectional view showing a part of the steering device of FIG. 1.

[0010] FIG. 3(A) is a top view of an input side housing in the first embodiment, and FIG. 3(B) is a sectional view of the input side housing in the first embodiment that is taken along line A-A in FIG. 3(A).

[0011] FIG. 4(A) is a top view of the input side housing in a second embodiment, and FIG. 4(B) is a sectional view of the input side housing in the second embodiment that is taken along line B-B in FIG. 4(A).

[0012] FIG. 5(A) is a top view of the input side housing in a third embodiment, and FIG. 5(B) is a sectional view of the input side housing in the third embodiment that is taken along line C-C in FIG. 5(A).DESCRIPTION OF THE INVENTION

[0013] In the following, an embodiment of a steering device in the present invention will be explained while referring to the drawings.

[0014] FIG. 1 is a longitudinal sectional view of a steering device of a first embodiment. FIG. 2 is an enlarged sectional view showing a part of the steering device in FIG. 1. As shown in FIGS. 1 and 2, the steering device of thepresent embodiment is disposed such that a steering shaft 5 is inclined relative to the vertical direction (top and bottom direction) and is disposed in an inclined posture as a whole in the engine room which is not shown. In addition, in FIGS.1 and 2, for the sake of explanation, the longitudinal direction of the steering shaft 5 is defined as an “axial direction,” the direction orthogonal to the steering shaft 5 is defined as a “radial direction,” and the direction around the steering shaft 5 is defined as a “circumferential direction.” Furthermore, in FIGS. 1 and 2, the side connected to a steering wheel (not shown) in the axial direction is referred to as a “one end,” and the side connected to a piston 18 is referred to as an “other end.” FIG. 3(A) is a top view of an input side housing 11 in the first embodiment, and FIG. 3(B) is a sectional view of the input side housing 11 in the first embodiment that is taken along line A-A in FIG. 3(A). Although, in FIGS. 3(A) and 3(B), for the sake of explanation, the input side housing 11 is shown extending in the vertical direction, in actual construction, it is arranged in an inclined posture relative to the vertical direction, as shown in FIGS. 1 and 2.

[0015] The steering device is an integral-type steering device used in large vehicles, and the like, and is mainly composed of a steering device main body 1, an electric motor (not shown), and an EPS controller (ECU) (not shown).

[0016] The steering device main body 1 is provided with a steering mechanism 2, a sector shaft 3, and a power cylinder 4.

[0017] The steering mechanism 2 is provided for inputting of steering operation (rotational force) transmitted from a steering wheel (not shown) and is provided with a steering shaft 5. The steering shaft 5 is partiallyaccommodated in a housing 6 and has an input shaft 7, a connecting shaft 8, an intermediate shaft 9, and an output shaft 10.

[0018] The input shaft 7 is formed in a cylindrical shape, and has one end connected to the steering wheel, and is provided for inputting of steering torque input from the driver. In addition, as shown in FIG. 2, the input shaft 7 is disposed such that one end portion thereof passes through an opening end surface 11a of the input side housing 11, while the other end portion is inserted into a substantially cylindrical connecting shaft 8. The input shaft 7 is rotatably supported by the inner peripheral surface of the cylindrical connecting shaft 8 via a needle bearing NB1 provided on the outer periphery of the input shaft 7.

[0019] The connecting shaft 8 accommodates the other end portion of the input shaft 7 at the one end and the other end of the connecting shaft 8 is connected to the intermediate shaft 9 via the spline portion 13 described below, thereby connecting the input shaft 7 and the intermediate shaft 9. As shown in FIG. 1 , the connecting shaft 8 has a cylindrical shape with a diameter stepwisely reduced from the one end toward the other end, and includes a large diameter cylindrical portion 8a located on the one end and a small diameter cylindrical portion 8b formed integrally with the large diameter cylindrical portion 8a and having a smaller diameter than the large diameter cylindrical portion 8a. An annular protruding portion 8c, which has an annular shape protruding radially outward, is formed at a position slightly above the axial center of the outer periphery of the large diameter cylindrical portion 8a.

[0020] As shown in FIG. 1 , between the outer periphery of the annular protruding portion 8c and the inner peripheral wall of the input side housing 11 ,which constitutes part of the housing 6, a bearing, such as a first ball bearing 12, is provided to rotatably support the connecting shaft 8.

[0021] Furthermore, the outer periphery of the small diameter cylindrical portion 8b is fixed to the inner periphery of an accommodation recess portion provided at an axial one end of the intermediate shaft 9 via a spline portion 13.

[0022] One end of the intermediate shaft 9 is connected to the input shaft 7 so as to be rotatable relative to the input shaft 7 via a first torsion bar 14. In addition, the other end of the intermediate shaft 9 is inserted into an opening recess portion formed in the diameter enlarged portion at one end of the output shaft 10. A speed reduction gear composed of a worm gear, which is connected to an electric motor not shown and in which a worm shaft not shown meshes with a worm wheel 15, is provided on the outer periphery at one end of the intermediate shaft 9.

[0023] One end of the output shaft 10 is connected to the intermediate shaft 9 so as to be rotatable relative to the intermediate shaft 9 via a second torsion bar 16, and outputs the steering torque input from the intermediate shaft 9 to a piston 18 via a ball screw mechanism 17, which is a conversion mechanism.

[0024] The ball screw mechanism 17 is composed of the output shaft 10 as a screw shaft that is formed, on the outer periphery at the other end thereof, with a ball groove 10a as a spiral groove, the piston 18 as a nut that is formed with a ball groove 18a as a spiral groove formed on the outer periphery of the output shaft 10 and corresponds to the ball groove 10a, and a plurality of balls 19 disposed between the ball groove 18a of the piston 18 and the ball groove 10a of the output shaft 10.

[0025] A rotary valve 20 known as a control valve is configured between the intermediate shaft 9 and the output shaft 10. The rotary valve 20 selectively supplies the working fluid supplied by a pump device, which is not shown and is mounted on the vehicle, according to the amount and direction of twist of the second torsion bar 16 that is obtained from the relative rotational angle between the intermediate shaft 9 and the output shaft 10 to first and second fluid chambers (pressure chambers) P1 and P2 described below.

[0026] The sector shaft 3 has a sector gear 3a, and rotates with the axial movement of the piston 18 by the meshing of the sector gear 3a with a rack tooth 18b of the piston 18 provided on the outer periphery at the other end of the steering shaft 5. The sector shaft 3 is connected to the turning wheel via a pitman arm not shown and is used for steering.

[0027] In this way, the ball screw mechanism 17, the sector shaft 3, and the pitman arm constitute a transmission mechanism that converts the rotation force (steering force) input to the steering shaft 5 into steering force for the turning wheel. In addition, when the steering device is composed without using the ball screw mechanism 17 and the like, as the transmission mechanism, for example, a rack bar and pinion shaft and the like to compose a rack-and-pinion mechanism can be used.

[0028] The power cylinder 4 is configured in a manner that the cylindrical piston 18 accommodated so as to be slidable within the housing 6 defines the first and second fluid chambers P1 and P2 that forms a pair of fluid chambers, and is a hydraulic actuator that generates an assist torque to assist the steering torque.

[0029] The torque sensor 21 is disposed within the input side housing 11 such that the most part of it is located on the ground side relative to the dust seal 40 described below in the axial direction of the steering shaft 5. As shown in FIG. 2, the torque sensor 21 is provided around the outer periphery more on one end side than the annular protruding portion 8c of the connecting shaft 8 in a state in which the first torsion bar 14 penetrates the annular torque sensor 21. The torque sensor 21 is mainly composed of a permanent magnet 22, a pair of first and second yokes 23 and 24, a pair of first and second magnetic concentration rings 25 and 26, and a magnetic sensor 27. The permanent magnet 22, the yokes 23 and 24, and the magnetic concentration rings 25 and 26 are all arranged such that they are substantially concentric with the rotation center line of the steering shaft 5.

[0030] The permanent magnet 22 is a magnetic member formed in a substantially cylindrical shape by a magnetic material and fixed to the outer periphery at one end portion of the connecting shaft 8. The permanent magnet 22 is configured such that N poles and S poles are alternately arranged (magnetized) along the circumferential direction of the permanent magnet 22.

[0031] A pair of yokes 23 and 24 are each formed in a substantially cylindrical shape using a soft magnetic material. One end that is the intermediate shaft 9 side of each of these yokes 23 and 24 is arranged in one row in the circumferential direction and is disposed to face the permanent magnet 22 in the radial direction. On the other hand, the other end of each of them is disposed such that the yoke 23 is positioned on the inner circumferentialside and the yoke 24 is positioned on the outer circumferential side, thereby facing each other in the radial direction.

[0032] The pair of magnetic concentration rings 25 and 26 are annular rings that concentrate the magnetic flux by the permanent magnets 22 that is leaked to the other ends of the two yokes 23 and 24 within a predetermined range, and are disposed between the other ends of the yokes 23 and 24 in the radial direction. The magnetic concentration ring 25 is positioned on the outer circumferential side, and the magnetic concentration ring 26 is positioned on the inner circumferential side, so as to face each other in the radial direction. A Hall element 28 is disposed between the magnetic concentration rings 25 and 26 in the radial direction. At a predetermined position in the circumferential direction of the magnetic concentration ring 25, a magnetic concentration portion 25a is provided by being pressed radially inward, while at a position facing the magnetic concentration portion 25a in the circumferential direction of the magnetic concentration ring 26, a magnetic concentration portion 26a is provided by being protruding radially outward.

[0033] The magnetic sensor 27 is composed of the Hall element 28 accommodated in the radial gap between the magnetic concentration portions 25a and 26a, and a first connection terminal 30 for connecting the Hall element 28 to a control substrate 29 disposed above the torque sensor 21. The magnetic sensor 27 detects the magnetic flux passing through the magnetic flux path between the magnetic concentration portions 25a and 26a by the Hall element 28 using the Hall effect of the Hall element 28, and outputs a signal corresponding to the magnetic flux to the control substrate 29. With this, thecalculation of the relative rotation angle between the input shaft 7 and the intermediate shaft 9, and the calculation of the steering torque based on the relative rotation angle are performed in the control board 29.

[0034] In addition, the control substrate 29 is provided with a secondL-shaped connection terminal 32 for connecting the control substrate 29 to a connector 31. The connector 31 is connected to an EPS controller which is not shown via a cable which is not shown.

[0035] The housing 6 is formed in a cylindrical shape with one end open and the other end closed, and is composed of an output side housing 33 that defines the first and second liquid chambers P1 and P2, an intermediate housing 34 that is provided to close the one end opening of the output side housing 33 and accommodates, thereinside, the output shaft 10, and the like, and the housing 11 that is connected to the intermediate housing 34 and accommodates the input shaft 7, the connection shaft 8, a part of the intermediate shaft 9, and the torque sensor 21.

[0036] A power cylinder main body portion 33a formed along the axial direction of the steering shaft 5, and a shaft portion 33b formed orthogonally to the power cylinder main body portion 33a and such that a part thereof faces the power cylinder main body portion 33a are provided inside the output side housing 33. The piston 18 connected to the output shaft 10 is accommodated inside the power cylinder main body 33a, thereby defining the first liquid chamber P1 on one end and the second liquid chamber P2 on the other end by the piston 18. In addition, the sector shaft 3 is accommodated within the shaft portion 33b such that one end thereof in the axial direction is connected to thepiston 18 and the other end is connected to a turning wheel via a pitman arm which is not shown.

[0037] The rack tooth 18b and a sector gear 3a, which mesh with each other, are provided on the outer peripheral portions of the piston 18 and the sector shaft 3, respectively. When the sector shaft 3 rotates in response to the axial movement of the piston 18 by the meshing of the rack tooth 18b with the sector gear 3a, the pitman arm is pulled in the vehicle body width direction and the direction of the turning wheel is changed.

[0038] As shown in FIG. 1 , on the inner circumferential side of the intermediate housing 34, a shaft insertion hole 34a through which the intermediate shaft 9 and the output shaft 10 are inserted so as to overlap with each other penetrates in shape having a diameter that is stepwisely reduced from one end to the other end in the axial direction. Then, at the large diameter portion on the one end, a bearing 35 is provided to rotatably support the output shaft 10. On the other hand, at the small diameter portion on the other end, an inlet port 36 communicating with a pump device which is not shown, a supply / discharge port 37 for suppling liquid pressure, which is introduced through the inlet port 36, to each of the liquid chambers P1 and P2, and discharges it from them, and a discharge port 38 for discharging working fluid discharged from each of the liquid chambers P1 and P2 to a reservoir tank which is not shown through the supply / discharge port 37 are provided. In addition, the supply / discharge port 37 communicates with the first fluid chamber P1 through a first supply / discharge passage L1 provided in the enlarged diameter portion on the one end of the output shaft 10, and communicate with the secondfluid chamber P2 through a second supply / discharge passage L2, and the like, provided inside the output side housing 33.

[0039] The input side housing 11 is made of a metal material, such as an aluminum alloy material, and has a cylindrical shape with a diameter stepwisely enlarged from one end toward the other end. As shown in FIGS. 1 and 2, a cylindrical protruding portion 39a is formed on the outer periphery of the axial end portion 39 on one end of the input side housing 11 , specifically in the region where the rack tooth 18b of the piston 18 overlaps axially with the steering shaft 5. This cylindrical protruding portion 39a protrudes radially outward from the outer periphery of the axial end portion 39 toward the radial outer side of the steering shaft 5. The connector 31 mentioned above, which connects the torque sensor 21 and a cable not shown, is fitted to the cylindrical protruding portion 39a.

[0040] As shown in FIG. 2, on the inner peripheral surface 39b of the axial end portion 39, at a position closer to the end surface 39c of the axial end portion 39, a step portion 39d recessed from the inner peripheral surface 39b of the axial end portion 39 toward the outside in the radial direction of the steering shaft 5 is formed. The step portion 39d extends continuously in an annular shape along the circumferential direction of the steering shaft 5. The dust seal 40, which is a ring-shaped sealing member, is fixed to the step portion 39d. More specifically, the dust seal 40 is fixed to the step portion 39d by being fitted into the step portion 39d from the inner side of the input side housing 11. The dust seal 40 suppresses dust and other foreign matters from entering the input side housing 11 from the outside.

[0041] In addition, as shown in FIGS. 1 and 2, an annular cover member 41 is provided on the outer periphery of the input shaft 7 of the steering shaft 5 to cover an end surface 39c of the axial end portion 39 of the input side housing 11. The length of the cover member 41 along the radial direction of the steering shaft 5 is greater than the outer diameter of the axial end portion 39 excluding the cylindrical protruding portion 39a. The cover member 41 includes an annular base portion 41a, a cylindrical fixed portion 41b extending from the inner edge of the annular base portion 41a toward the dust seal 40, and an annular curved portion 41c curved from the outer edge of the annular base portion 41a toward the input side housing 11.

[0042] As shown in FIG. 2, an annular protruding portion 41 d protruding from the inner peripheral surface of the fixed portion 41 b toward the input shaft 7 is formed at the axial center position of the inner peripheral surface of the fixed portion 41 b. This protruding portion 41 d is fitted into an annular retaining groove 7a formed on the outer periphery of the input shaft 7, thereby fixing the cover member 41 to the input shaft 7. An axial end 39e on the other end of the fixed portion 41 b overlaps with the axial end portion 39 of the input side housing 11 in the radial direction of the steering shaft 5.

[0043] As shown in FIG. 2, a distal end surface 39f is formed on the other end of the curved portion 41c, and this distal end surface 39f is located at a position more on one end than the axial end 39e on the other end of the fixed portion 41 b. The distal end surface 39f overlaps with the axial end portion 39 of the input side housing 11 in the radial direction of the steering shaft 5.

[0044] In addition, between the annular base portion 41a, the fixed portion 41b, and the curved portion 41c, there is formed a continuously annular passage 42. The passage 42 communicates the outer side of the input side housing 11 with a continuously annular space S formed between the input shaft 7, the dust seal 40, and the axial end portion 39.

[0045] For example, when rainwater is splashed up by a turning wheel from a puddle and enters the engine room, it may be accumulated in the space S through the passage 42. In addition, for example when water enters the engine room during vehicle washing, it may also be accumulated in the space S through the passage 42. As shown in FIGS. 1 and 2, since the steering device is inclined as a whole such that the steering shaft 5 is inclined relative to the vertical direction (top and bottom direction), as compared to the cylindrical protruding portion 39a side, water is easily accumulated on the side closer to the bottom side in the top and bottom direction within the space S, namely, on the opposite side of the cylindrical protruding portion 39a with the input shaft 7 therebetween in the present embodiment.

[0046] A first groove 43, which serves as a drain, is formed at the axial end portion 39 of the input side housing 11 , to drain water accumulated in the space S to the outside of the input side housing 11. The first groove 43 is formed by the die-casting process used to manufacture the metal input side housing 11. As shown in FIG. 3(A), the first groove 43 is formed on the opposite side of the cylindrical protruding portion 39a in the end surface 39c of the axial end portion 39 of the input side housing 11. More specifically, the first groove 43 is formed at the position in the end surface 39c of the axial end portion 39 that is farthestfrom the cylindrical protruding portion 39a. In addition, in the present embodiment, although a single first groove 43 is formed on the opposite side of the cylindrical protruding portion 39a in the end surface 39c of the axial end portion 39, the plurality of first grooves 43 may be formed.

[0047] The first groove 43 is a groove that extends continuously along the radial direction of the steering shaft 5. In other words, the first groove 43 is a groove that is recessed from the end surface 39c of the axial end portion 39 toward the other end and extends toward a rotation center 0 of the steering shaft 5 from the outside of the input side housing 11 with a constant groove width. In addition, the first groove 43 is not necessarily a groove extending with a constant groove width, but may be a groove extending with a non-constant groove width, such as a groove whose groove width tapers toward the radial outer side of the steering shaft 5 or a groove whose groove width tapers toward the radial inner side of the steering shaft 5. Furthermore, the depth of the first groove 43 is set to the depth from the end surface 39c of the axial end portion 39 to the vicinity of the step portion 39d. The depth of the first groove 43 is preferably set as large as possible within the range where sufficient rigidity is ensured for the step portion 39d to hold the dust seal 40. As shown in FIG. 2, a bottom surface 43a of the first groove 43 is inclined so as to approach the ground side as it extends toward the radial outer side of the steering shaft 5. Water in the space S is discharged to the outside of the input side housing 11 along the inclination of the bottom surface 43a.

[0048] According to the configuration, in the steering device, when the driver steers the steering wheel, the working fluid pressure-fed by the pump device issupplied to one of the liquid chambers P1 and P2 corresponding to the steering direction via the rotary valve 20, and the working fluid (excess portion) corresponding to the supply amount is discharged from the other liquid chamber P1 or P2 to the reservoir tank. As a result of the piston 18 being driven by the liquid pressure, an assist torque based on the liquid pressure acting on the piston 18 is imparted to the sector shaft 3.

[0049] As described above, in the first embodiment, the step portion 39d is formed on the inner peripheral surface of the axial end portion 39 of the input side housing 11. This step portion 39d has a dust seal 40 fitted from the inner side of the input side housing 11 , and therefore, a space S in which water that has entered the engine room can accumulate exists between the steering shaft 5, the axial end portion 39 of the input side housing 11 , and the dust seal 40. A first groove 43 capable of draining water accumulated in the space S is formed on the axial end portion 39 of the input side housing 11. By discharging the water from the space S to the outside of the input side housing 11 via the first groove 43, corrosion of the inner peripheral surface of the input side housing 11, particularly the inner peripheral surface of the step portion 39d, is reduced, thereby suppressing the flow of water toward the torque sensor 21. Therefore, failure of various electronic components constituting the torque sensor 21 , such as the magnetic sensor 27, can be suppressed.

[0050] Further, in the present embodiment, in the steering device, the steering shaft 5 is disposed in a posture inclined relative to the vertical direction. In addition, the first groove 43 is formed on the side of the axial end 39 of the input side housing 11 that is closer to the ground. Since the steering device isdisposed in the inclined posture, the bottom surface 43a of the first groove 43 is also inclined relative to the vertical direction. Consequently, water in the space S can be rapidly discharged to the outside of the input side housing 11 along the inclined bottom surface 43a of the first groove 43.

[0051] FIG. 4(A) is a top view of the input side housing 11 of a second embodiment, and FIG. 4(B) is a sectional view of the input side housing 11 of the second embodiment which is taken along line B-B in FIG. 4(A). In addition, although, in FIGS. 4(A) and 4(B), for the sake of explanation, the input side housing 11 is shown extending in the vertical direction, in actual construction, it is disposed in an inclined posture relative to the vertical direction, as shown in FIGS. 1 and 2.

[0052] In the steering device of the second embodiment, the first groove 43 of the first embodiment is eliminated, and a second groove 44 is newly provided extending at an angle different from that of the first groove 43.

[0053] As shown in FIG. 4(A), the second groove 44 extends from the outside of the input side housing 11 toward a position offset from the rotation center O of the steering shaft 5 with a constant groove width. More specifically, as shown in FIG. 4(A), the second groove 44 extends from the outside of the input side housing 11 toward a position offset from the rotation center O of the steering shaft 5, so as to intersect a line M that divides the width of the cylindrical protruding portion 39a (the width in the vertical direction of FIG. 4(A)) into two equal parts, from the side below the line M. In addition, the second groove 44 may not be a groove extending with a constant groove width, but may be a groove extending with a non-constant groove width, such as a groove whosegroove width tapers toward the outside of the input side housing 11 or a groove whose groove width tapers toward the inside of the input side housing 11.Since the second groove 44 extends while being inclined relative to the line M, its total length is longer than that of the first groove 43 of the first embodiment, which extends along the line M. Consequently, when water enters the engine room, it is difficult for the water to flow into the space S through the second groove 44 from the outer side of the input side housing 11.

[0054] In addition, in the present embodiment, although a single second groove 44 is formed on the opposite side of the cylindrical projection 39a in the end surface 39c of the axial end portion 39, the plurality of second grooves 44 may be formed.

[0055] As described above, in the second embodiment, the second groove 44 extends from the outside of the input side housing 11 toward a position offset from the rotation center 0 of the steering shaft 5. Consequently, the total length of the second groove 44 is longer than that of the first groove 43, thereby suppressing water that has entered the engine room from reaching the space S via the second groove 44.

[0056] FIG. 5(A) is a top view of the input side housing 11 of a third embodiment, and FIG. 5(B) is a sectional view of the input side housing 11 of the third embodiment that is taken along line C-C in FIG. 5(A). In addition, although, in FIGS. 5(A) and 5(B), for the sake of explanation, the input side housing 11 is shown extending in the vertical direction, in actual construction, it is disposed in an inclined posture relative to the vertical direction, as shown in FIGS. 1 and 2.

[0057] In the steering device of the third embodiment, the first groove 43 of the first embodiment is eliminated, and a new through hole 45 is provided as a drain.

[0058] As shown in FIG. 5(B), the through hole 45 penetrates the axial end portion 39 from the outside of the input side housing 11 toward the rotation center O of the steering shaft 5 along the radial direction of the steering shaft 5. The through hole 45 is formed by machining the metal input side housing 11 using, for example, a drill. As shown in FIG. 5(B), the through hole 45 extends along its entire length with a constant outer diameter between the end surface 39c of the axial end portion 39 and the step portion 39d. In addition, the through hole 45 may extend in a conical taper shape rather than maintaining a constant outer diameter along its entire length. Furthermore, as shown in FIG.5(A), the through hole 45 is formed in a circular shape when viewed from the outside of the input side housing 11. In addition, the shape of the through hole 45 is not limited to a circular shape and may be other shapes, such as a rectangular shape.

[0059] Although, in the present embodiment, a single through hole 45 is formed on the opposite side of the cylindrical protruding portion 39a in the end surface 39c of the axial end portion 39, the plurality of through holes 45 may be formed.

[0060] As described above, in the third embodiment, a through hole 45 is formed in the axial end portion 39 of the input side housing 11 to discharge water in the space S to the outside of the input side housing 11. By such a through holes 45, water in the space S is also discharged to the outside of the input sidehousing 11, thereby reducing corrosion of the inner peripheral surface of the input side housing 11 and suppressing failure of the electronic components of the torque sensor 21.

[0061] In addition, the through hole 45 does not open in the end surface 39c of the axial end portion 39, and the “top” side in the top and bottom direction is a wall portion, and water that has entered the engine room collides with this wall portion and is returned to the outside of the input side housing 11. Therefore, it is possible to suppress water from accumulating in the space S through the through hole 45.

Claims

CLAIMSClaim 1. A steering device comprising:a steering shaft to which rotational force from a steering wheel is input; a transmission mechanism for transmitting the rotational force of the steering shaft to a turning wheel;a torque sensor that is provided around the steering shaft and detects a steering torque of the steering shaft;a housing that has an opening end surface through which the steering shaft passes, accommodates a part of the steering shaft, and is formed, on an inner peripheral surface of an axial end portion on an opening end surface side thereof, with a step portion having a diameter stepwisely enlarged toward an opposite side of the steering wheel in the axial direction of the steering shaft; and a ring-shaped sealing member provided on the step portion to seal between an inner peripheral surface of the housing and an outer peripheral surface of the steering shaft,wherein a space is provided between the steering shaft, the axial end portion of the housing, and the sealing member, andwherein a drain is formed in a portion of the axial end portion of the housing that is positioned on a steering wheel side relative to the sealing member, so as to communicate between the space and an outside of the housing to discharge water accumulated in the space.Claim 2. The steering device according to claim 1 ,wherein the steering shaft is disposed in an inclined posture relative to a vertical direction, andwherein the drain is formed on a side of the axial end portion of the housing that is closer to a ground.Claim 3. The steering device according to claim 2,wherein the drain is a groove formed on an end surface of the axial end portion of the housing and extending continuously along a radial direction of the steering shaft.Claim 4. The steering device according to claim 2,wherein the drain is a through hole penetrating the axial end portion of the housing along a radial direction of the steering shaft.Claim 5. The steering device according to claim 2,wherein the drain extends from an outside of the housing toward a rotation center of the steering shaft.Claim 6. The steering device according to claim 2,wherein the drain extends from an outside of the housing toward a position offset from a rotation center of the steering shaft.

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