JP2008207612A - Electric power steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tilt adjustable electric power steering device which has a simple structure and can surely pass through a steering column to a vehicle body side. <P>SOLUTION: A pivot member 19 capable of swingingly supporting a column bracket 17 of a steering column includes a tubular member 38 fixed so as to pass a vehicle side member. The tubular member 38 rotatably supports the column bracket 17 through an insulating bush 34. A conductive linear spring member 43 for connecting the tubular member 38 and the column bracket 17 is provided. The linear spring member 43 includes an engaging part 44 engaged so as to pass the column bracket 17, and a contact part 45 which elastically contacts with inner surfaces of a plurality of grooves 38c of the outer periphery surface 38b of the tubular member 38. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electric power steering apparatus capable of tilt adjustment.

In the electric power steering device, even if a horn current flows through the input shaft of the steering shaft, in order to detect the steering torque satisfactorily, between the sensor shaft supported in the torque detection means and the input shaft, An apparatus in which an insulating member is interposed has been proposed (see, for example, Patent Document 1).
JP 2000-346726 A

  By the way, in an electric power steering apparatus to which a tilt adjustment mechanism that supports a steering column around a pivot member fixed to the vehicle body side and that can adjust the position of the steering wheel is added, it is fixed to the vehicle body side. The pivot member thus supported is supported by an insertion hole of a bracket fixed to the steering column via a synthetic resin bush. Thereby, at the time of tilt adjustment, the bush and the pivot member can smoothly rotate relative to each other.

  However, an insulating bush is interposed between the pivot member and the bracket, and the two are electrically disconnected. If it does so, the sensor housing which accommodates a torque detection means and comprises a part of steering column will be electrically insulated from a vehicle body. For this reason, it becomes easy to superimpose noise by electromagnetic induction from the outside to the sensor housing that houses the coil and electronic parts of the torque detection means, and the operation of the torque detection means may become unstable. In order to prevent this, it is desirable to ground the sensor housing to the vehicle body side and keep the same potential as the vehicle body. Therefore, it is necessary to connect the steering column holding the torque sensor, the electric motor, and the ECU for controlling the driving of the electric motor to the vehicle body side by some method.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an electric power steering device that has a simple structure and can reliably connect a steering column to the vehicle body.

  In order to achieve the above object, the present invention provides a pivot member (19) including a conductive cylindrical member (38) fixed to the vehicle body side member (18) so as to be conductive, and is rotatable around the pivot member. A steering column (3) supported by the steering column, an electric motor (16) for assisting steering supported by the steering column, a conductive bracket (17) provided so as to be rotatable integrally with the steering column, and the bracket A pair of insulating bushes (34) respectively inserted into the insertion holes (33) of the pair of side plates (29, 30), and a conductive linear spring member for connecting the cylindrical member and the bracket ( 43; 43A; 43B; 43C), and the cylindrical member rotatably supports the bracket via the pair of bushes while being inserted into the pair of bushes. A plurality of grooves (38c) are formed on the outer peripheral surface (38b) of the cylindrical member so as to extend in the circumferential direction. The linear spring member includes a locking portion (44) locked to the bracket so as to be conductive, and a contact portion (45) that elastically contacts each of the inner surfaces of the plurality of grooves. It is a feature.

  The inventor of the present application can secure conduction at low cost by providing a contact portion that elastically contacts the cylindrical member of the pivot member on a linear spring member such as a wire having a locking portion locked to the bracket. I thought. Further, in order to improve the reliability of connection between the linear spring member and the cylindrical member, a plurality of grooves extending in the circumferential direction of the outer peripheral surface of the cylindrical member are provided, and the contact portion of the linear spring member has the plurality of Elastic contact was made with the inner surface of the groove. Thereby, between a bracket and a cylindrical member can be reliably conducted via a linear spring member. Moreover, even if there is variation in the shape and dimension of the linear spring member, the linear spring member is brought into contact with the inner surfaces of the plurality of grooves, so that the linear spring member can be reliably contacted.

  The bracket includes a connecting plate (31) that connects between the pair of side plates and extends in parallel with the axial direction (X1) of the cylindrical member, and a pair of locking members that are locked to the connecting plate as the locking portions. The linear spring member includes a pair of extending portions (48; 48A; 48B; 48C) extending from the pair of engaging portions and a connecting portion that connects between the pair of extending portions. (49) includes a U-shaped contact portion forming portion (46; 46A; 46B; 46C), and the contact portion (45) is provided in each of the pair of extending portions. (Claim 2). In this case, the linear spring member can be formed by one wire, and the manufacturing cost can be reduced.

  The connecting plate has four surfaces (51, 52, 53, 54) extending in a direction parallel to the axial direction of the cylindrical member, has a rectangular cross section, and each of the pair of locking portions includes: In some cases, the connecting plate is locked to the four surfaces. In this case, the linear spring member can be firmly locked to the buke rat, and as a result, a contact pressure is surely generated between the linear spring member and the cylindrical member, and the conduction between the two is ensured. can do.

A bent portion (47) may be formed between each locking portion and the corresponding extended portion (claim 4). In this case, the contact portion of each extending portion can be pressed against the tubular member by the repulsive force of the elastic deformation of the bent portion, and the electrical connection between the linear spring member and the tubular member can be further ensured. .
Each of the pair of extending portions may have one or a plurality of bent portions (71) when viewed along the axial direction of the tubular member (claim 5). In this case, by bending each bent portion, the linear spring member can be reliably brought into elastic contact with the tubular member in a state where a sufficient amount of bending is ensured as a whole.

Each of the pair of extending portions includes a flat portion (70) having the contact portion, and in this flat portion, the cross-sectional diameter (D1) in the radial direction (Y1) of the tubular member is relatively small, and the tube The cross-sectional diameter (D2) in the axial direction of the member may be relatively large (claim 6). In this case, the contact resistance between the outer peripheral surface of the cylindrical member and the linear spring member can be reduced.
In the above description, the alphanumeric characters in parentheses represent reference numerals of corresponding components in the embodiments described later, but the scope of the claims is not limited by these reference numerals.

Preferred embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a longitudinal sectional view of a main part of an electric power steering apparatus according to an embodiment of the present invention. Referring to FIG. 1, an electric power steering apparatus 1 includes a steering column 3 that rotatably supports a steering shaft 2. A steering wheel 4 is connected to one end 2 a of the steering shaft 2 so as to be integrally rotatable. A pinion shaft 8 is connected to the other end 2 b of the steering shaft 2 via a universal joint 5, an intermediate shaft 6 and a universal joint 7. It is linked so that it can rotate together.

The pinion 8a formed on the pinion shaft 8 and the rack shaft 9 meshing with the pinion 8a constitute a steering mechanism 10 composed of a rack and pinion mechanism. Although not shown, each end of the rack shaft 9 is connected to a corresponding steering wheel via a tie rod and a knuckle arm.
The steering column 3 includes an upper tube 11, a lower tube 12 fitted to the upper tube 11, and a sensor housing 13 and a gear housing 14 provided integrally with the lower tube 12.

The sensor housing 13 accommodates and holds a torque sensor 15 for detecting a steering torque related to the steering shaft 2. A motor housing 16 a of an electric motor 16 for applying a steering assist force to the steering shaft 2 is fixed to the gear housing 14.
A lower portion of the steering column 3 is rotatably supported by a tilt hinge mechanism including a pivot member 19. That is, the column bracket 17 is fixed to the bottom portion 14a of the gear housing 14 by a screw 50, and this column bracket 17 is rotatably supported by a pivot member 19 fixed to a fixed bracket 18 as a vehicle body side member. Has been. The fixed bracket 18 is fixed to the vehicle body 20. The entire steering column 3 is swung around the pivot member 19 together with the steering wheel 4 so that the height position of the steering wheel 4 is adjusted.

On the other hand, in relation to the upper tube 11 of the steering column 3, a support mechanism 22 is provided that can switch the position of the steering column 3 between a locked state and an unlocked state by operating the operation lever 21.
A reduction mechanism 23 is accommodated in the gear housing 14. The speed reduction mechanism 23 includes a drive gear 24 that is driven by the rotating shaft 16 b of the electric motor 16, and a driven gear 25 that meshes with the drive gear 24 and rotates integrally with the steering shaft 1.

When the steering wheel 4 is steered, the control unit P, which is an ECU, controls the electric motor 16 according to the torque detection result detected by the torque sensor 15 and the vehicle speed detection result detected by a vehicle speed sensor (not shown). The steering assist force is applied to the steering shaft 2 via the speed reduction mechanism 23.
Referring to FIG. 2, the fixed bracket 18 as a vehicle body side member has a pair of side plates 26 and 27 facing each other, and an insertion hole 28 is formed in each of the pair of side plates 26 and 27. .

  The column bracket 17 includes a pair of side plates 29 and 30 that face the inner side surfaces 26a and 27a of the pair of side plates 26 and 27 of the fixed bracket 18, respectively, and a connecting plate 31 that connects one end portions of the pair of side plates 29 and 30 to each other. , And a mounting plate 32 extending outwardly orthogonally to the other end of each of the pair of side plates 29 and 30. The screw 50 passes through the mounting plate 32 and is screwed into the bottom portion 14 a of the gear housing 14, whereby the column bracket 17 is fixed to the gear housing 14.

An insertion hole 33 is formed in each of the pair of side plates 29 and 30 of the column bracket 17. Insulating bushes 34 made of synthetic resin are mounted in the insertion holes 33 of the pair of side plates 29 and 30, respectively.
Each bush 34 has a cylindrical main body 35 fitted in the insertion hole 33 and an annular flange 36 extended to one end of the main body 35. Each flange 36 is interposed between the corresponding side plates 26, 29; 27, 30 of the fixed bracket 18 and the column bracket 17. The bush 34 is formed with a slit 37 extending in the axial direction, whereby the bush 34 has an end in the circumferential direction. The main body 35 of the bush 34 is fitted into the insertion hole 33 while being elastically reduced in diameter.

  The pivot member 19 is inserted into the cylindrical member 38 and the conductive cylindrical member 38 sandwiched between the pair of side plates 26 and 27 of the fixing bracket 18 while being inserted into the pair of bushes 34. A fixing bolt 39 as a fixing shaft for fixing the cylindrical member 38 to the fixing bracket 18 is provided. The cylindrical member 38 supports the column bracket 17 and the steering column 3 through the bush 34 so as to be rotatable. The axial direction X1 of the tubular member 38 is parallel to the connecting plate 31 of the column bracket 17.

  The fixing bolt 39 has a threaded portion 40 a at one end, and is formed at the other end of the screw shaft 40 and the screw shaft 40 inserted through the insertion holes 28 of the pair of side plates 26 and 27 of the cylindrical member 38 and the fixing bracket 18. And a head 41 formed. A nut 42 as an end member is screwed to the threaded portion 40 a at one end of the screw shaft 40. The head 41 of the fixing bolt 39 is in contact with the outer surface 26 b of one side plate 26 of the fixing bracket 18, and the nut 42 is in contact with the outer surface 27 b of the other side plate 27 of the fixing bracket 18.

  By screwing the fixing bolt 39 into the nut 42, the cylindrical member 38 of the pivot member 19 is sandwiched between the pair of side plates 26 and 27 of the fixing bracket 18, whereby the cylindrical member 38 is attached to the fixing bracket 18. It is concluded. The pair of end faces 38a of the cylindrical member 38 are pressed against the inner side surfaces 26a, 27a of the corresponding side plates 26, 27 of the fixing bracket 18, and as a result, the electrical connection between the fixing bracket 18 as the vehicle body side member and the cylindrical member 38 is achieved. Continuity is ensured.

On the other hand, an insulating bush 34 is interposed between the tubular member 38 and the side plates 29 and 30 of the column bracket 17, and electrical continuity between the two is interrupted. Therefore, in the present embodiment, a conductive linear spring member 43 having a round cross section, for example, is provided for connecting the cylindrical member 38 and the column bracket 17.
As shown in FIG. 3, a plurality of grooves 38c extending in the circumferential direction of the cylindrical member 38 are formed on the outer peripheral surface 38b of the cylindrical member 38 so as to have a semicircular cross section as shown in FIG. As shown in FIG. 3, the linear spring member 43 has a pair of engaging portions 44 that are electrically connected to the column bracket 17 and a U-shape that connects the pair of engaging portions 44. And a contact portion forming portion 46 that forms a contact portion 45 with respect to the tubular member 37.

  Referring to FIG. 4, the connecting plate 31 of the column bracket 17 has four surfaces extending in a direction parallel to the axial direction X1 of the cylindrical member 38. That is, the connecting plate 31 of the column bracket 17 includes a first surface 51 that faces the outer peripheral surface 38b of the cylindrical member 38, a second surface 52 that faces the first surface 51, and the first and second surfaces. It has the 3rd surface 53 and the 4th surface 54 orthogonal to the surfaces 51 and 52, and has comprised the cross-sectional rectangle enclosed by these surfaces 51-54.

Referring to FIGS. 3 and 4, each locking portion 44 includes a first portion 61 as an end portion, a second portion 62 extending orthogonally from the first portion 61, and a second portion. A third portion 63 extending orthogonally from the second portion 62 and a fourth portion 64 extending orthogonally from the third portion 63 are provided.
As shown in FIG. 4, the first portion 61 is locked to the third surface 53 in a state along the third surface 53 of the connecting plate 31. The second portion 62 is locked to the second surface 52 in a state along the second surface 52. The third portion 63 is locked to the fourth surface 54 in a state along the fourth surface 54. The fourth portion 64 is locked to the first surface 51 in a state along the first surface 51. In this way, the locking portion 44 is locked to the four surfaces (first to fourth surfaces 51 to 54) surrounding the connecting plate 31, so that the locking is reliable.

  Referring to FIGS. 3 and 4, the contact portion forming portion 46 includes a pair of extending portions 48 extending in parallel with each other from the fourth portions 64 of the pair of locking portions 44 via the bent portions 47. In addition, as shown in FIG. 3, the whole has a U-shape, including a curved connecting portion 49 that connects the pair of extending portions 48. As shown in FIG. 5, each of the pair of extending portions 48 is provided with a contact portion 45 that elastically contacts the inner surfaces of the plurality of grooves 38 c of the tubular member 38. In the example of FIG. 5, the extended section 48 with a round cross section inserted into the groove 38 c having a semicircular cross section is provided with a contact portion 45 that contacts the inner surface of the groove 38 c on a part of the arc-shaped outer peripheral surface. ing.

  According to the present embodiment, the following operational effects are obtained. That is, the linear spring member 43 locked to the column bracket 17 has contact portions 45 that respectively contact the inner surfaces of the plurality of grooves 38c extending in the circumferential direction of the outer peripheral surface 38b of the cylindrical member 38. The contact portion 45 is elastically in contact with the inner surface of the corresponding groove 38c. Even if there is a variation in the shape and the like of the linear spring member 43, the linear spring member 43 is brought into contact with the inner surfaces of the plurality of grooves 38c, so that it can be reliably contacted.

  Thereby, the reliability of the connection between the linear spring member 43 and the cylindrical member 38 can be improved. As a result, the gap between the column bracket 17 and the cylindrical member 38 is interposed via the linear spring member 43. It is possible to ensure conduction. As a result, the steering column 3 can be reliably grounded with respect to the vehicle body 20, and the occurrence of electromagnetic interference with the electric power steering apparatus 1 can be prevented.

  Further, the connecting plate 31 of the column bracket 17 has four surfaces (first to fourth surfaces 51 to 54) extending in parallel with the axial direction X1 of the tubular member 38 and has a rectangular cross section. Since each of the pair of locking portions 44 of the spring member 43 is locked to the four surfaces (first to fourth surfaces 51 to 54) of the connecting plate 31, the linear spring member 43 is It can be firmly locked to the column buke rat 17. As a result, it is possible to reliably generate contact pressure with respect to the tubular member 38, and to further ensure conduction between the tubular member 38 and the linear spring member 43.

Further, since the bent portions 47 are formed between the respective locking portions 44 of the linear spring member 43 and the corresponding extended portions 48, in addition to the elastic repulsive force of the extended portions 48 themselves, the bent portions The contact portion 45 of each extending portion 48 can be pressed against the tubular member 38 using the elastic repulsive force 47. Therefore, the conduction between the linear spring member 43 and the tubular member 38 can be further ensured.
In the embodiment of FIG. 5, the extending portion 46 of the contact portion forming portion 46 has a round cross section, but as shown in FIG. 6, at least a portion of the extending portion 46 that is inserted into the groove 38 c, A flat portion 70 may be provided, and the flat portion 70 may have a contact portion 45 with respect to the inner surface of the groove 38c of the cylindrical member 38.

That is, as the cross-sectional diameter of the flat portion 70, the cross-sectional diameter D1 in the radial direction Y1 of the cylindrical member 38 is relatively small, and the cross-sectional diameter D2 in the axial direction X1 of the cylindrical member 38 is relatively large. Thereby, the contact area of the contact part 45 with respect to the inner surface of the groove | channel 38c of the cylindrical member 38 can be enlarged, and contact resistance can be reduced.
FIG. 7 shows another embodiment of the present invention. Referring to FIG. 7, in the present embodiment, the contact portion of linear spring member 43 </ b> A when viewed along axial direction X <b> 1 of cylindrical member 38 (not shown, but perpendicular to the paper surface). The bent portion 71 is formed in the middle of each of the pair of extending portions 48A of the forming portion 46A. In FIG. 7, only the bent part 71 of one extending part 48A is shown. By providing the bent portion 71, the extended portion 48A has a U shape. The bent portion 71 is bent in the opposite direction to the bent portion 47 between the extended portion 48 </ b> A and the fourth portion 64 of the locking portion 44.

In the present embodiment, in addition to the elastic deformation of the bent portion 47, the bent portion 71 is elastically deformed so that the linear spring member 43 is securely attached to the tubular member 38 in a state in which a sufficient amount of bending is ensured as a whole. Can be elastically contacted. In addition, you may make it provide the some bending part 71 in each extension part 48A.
The present invention is not limited to the above-described embodiments. For example, as a modification of the embodiment of FIG. 4, as shown in FIG. 8, the axial direction X1 (not shown) of the cylindrical member 38 is shown. (Not in the direction perpendicular to the plane of the drawing), but a portion of the extended portion 48B of each contact portion forming portion 46B of the linear spring member 43B is curved along the circumferential direction of the tubular member 38. Thus, the contact area of the contact portion 45 with respect to the tubular member 38 may be increased.

Further, as a modification of the embodiment of FIG. 7, as shown in FIG. 9, when viewed along the axial direction X1 of the cylindrical member 38 (not shown, but perpendicular to the paper surface), A part of the extended portion 48C of each contact portion forming portion 46C of the cylindrical spring member 43C is curved along the circumferential direction of the tubular member 38 so that the contact area of the contact portion 45 with the tubular member 38 is expanded. May be.
In addition, various modifications can be made within the scope of the claims of the present invention.

1 is a schematic configuration diagram of an electric power steering apparatus according to an embodiment of the present invention. It is sectional drawing of a tilt hinge mechanism. It is a perspective view of the principal part of a tilt hinge mechanism. It is sectional drawing of the principal part of a tilt hinge mechanism. It is a schematic sectional drawing of the periphery of the contact area of a linear spring member and a cylindrical member. It is a schematic sectional drawing of the periphery of the contact area | region of the linear spring member and cylindrical member in another embodiment of this invention. It is sectional drawing of the principal part of the tilt hinge mechanism in another embodiment of this invention. It is sectional drawing of the principal part of the tilt hinge mechanism in another embodiment of this invention. It is sectional drawing of the principal part of the tilt hinge mechanism in another embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Electric power steering device, 3 ... Steering column, 16 ... Electric motor, 17 ... Column bracket (bracket), 18 ... Fixed bracket (vehicle body side member), 10 ... Pivot member, 29, 30 ... Insertion hole, 31 ... Connection Plate, 34 ... Bush, 38 ... Cylindrical member, 38b ... Outer peripheral surface, 38c ... Groove, 43, 43A, 43B, 43C ... Linear spring member, 44 ... Locking portion, 45 ... Contact portion, 46, 46A, 46B , 46C ... contact portion forming portion, 47 ... bent portion, 48, 48A, 48B, 48C ... extending portion, 49 ... connecting portion, 51 ... first surface, 52 ... second surface, 53 ... third surface. 54 ... 4th surface, 61 ... 1st part, 62 ... 2nd part, 63 ... 3rd part, 64 ... 4th part, 70 ... flat part, 71 ... bending part, X1 ... axial direction , Y1 ... radial direction

Claims (6)

A pivot member including a conductive cylindrical member fixed to the vehicle body side member in a conductive manner;
A steering column that supports an electric motor for assisting steering and is supported so as to be rotatable around a pivot member;
A conductive bracket provided to rotate integrally with the steering column;
A pair of insulating bushes respectively inserted into the insertion holes of the pair of side plates of the bracket;
A conductive linear spring member connecting the cylindrical member and the bracket;
The cylindrical member is rotatably inserted in the pair of bushes, and supports the bracket rotatably via the pair of bushes.
A plurality of grooves are formed on the outer peripheral surface of the cylindrical member so as to extend in the circumferential direction,
The electric power steering apparatus according to claim 1, wherein the linear spring member includes an engaging portion that is electrically connected to the bracket and a contact portion that elastically contacts the inner surfaces of the plurality of grooves. In Claim 1, the bracket includes a connecting plate that connects the pair of side plates and extends parallel to the axial direction of the cylindrical member,
As the locking portion, a pair of locking portions locked to the connecting plate is provided,
The linear spring member includes a pair of extending portions extending from the pair of locking portions and a connecting portion that connects between the pair of extending portions, and includes a U-shaped contact portion forming portion,
The electric power steering apparatus, wherein the contact portion is provided in each of the pair of extending portions. The connecting plate according to claim 2, wherein the connecting plate has four surfaces extending in a direction parallel to the axial direction of the cylindrical member, and has a rectangular cross section.
Each of said pair of latching | locking parts is latched by the said 4 surface of a connection board, The electric power steering apparatus characterized by the above-mentioned.   4. The electric power steering apparatus according to claim 1, wherein a bent portion is formed between each locking portion and a corresponding extending portion.   5. The structure according to claim 2, wherein each of the pair of extending portions has one or a plurality of bent portions when viewed along the axial direction of the cylindrical member. Electric power steering device.   In any 1 paragraph of Claims 1 thru / or 5, each of the above-mentioned pair of extension parts includes a flat part which has the above-mentioned contact part, and the section diameter about the diameter direction of a cylindrical member is relatively in this flat part. An electric power steering apparatus characterized by being small and having a relatively large cross-sectional diameter in the axial direction of the cylindrical member.

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