JP2017124784A - Electric power steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric power steering device improved in assemblability.SOLUTION: An electric power steering device 100 comprises: an input shaft 13 to which steering torque is inputted; an output shaft 15 connected to the input shaft 13 through a torsion bar 14; a torque sensor 40, mounted across the input shaft 13 and the output shaft 15, which detects steering torque; a housing 5 which stores the input shaft 13, the output shaft 15 and the torque sensor 40; and a rotation stop portion 80 that restricts relative rotation of the torque sensor 40 to the housing 5 by engaging with the torque sensor 40. The housing 5 has a first housing 50 that supports rotationally the input shaft 13, a second housing 60 which is fastened to the first housing 50 to support rotationally the output shaft 15, and an intermediate portion 70 held by the first housing 50 and the second housing 60. The rotation stop portion 80 is provided in the intermediate portion 70.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an electric power steering apparatus.

  Patent Document 1 discloses a power steering device (also referred to as “electric power steering device”) including a steering shaft rotatably provided in a housing and a torque sensor provided on the steering shaft. . The housing includes an input side housing portion positioned on the input shaft portion side of the steering shaft, and an output side housing portion positioned on the output shaft portion side of the steering shaft. The input side housing part and the output side housing part are fastened using a mounting screw. A retainer plate is sandwiched between the input side housing portion and the output side housing portion, and the torque sensor is accommodated in the input side housing portion.

JP 2001-213334 A

  When the torque sensor rotates together with the input shaft portion, it cannot detect the steering torque input to the input shaft portion. For this reason, it is necessary to provide a structure for restricting the rotation of the torque sensor together with the input shaft portion in the electric power steering apparatus.

  In the electric power steering device described in Patent Document 1, it is conceivable to provide a rotation stop portion that engages with the torque sensor in the input side housing portion in order to restrict the rotation of the torque sensor.

  However, in the assembly of the electric power steering device described in Patent Document 1, first, the output shaft portion and the input shaft portion are connected, the output shaft portion is inserted through the insertion hole of the retainer plate, and the torque sensor is connected to the input shaft portion. It is attached. Thereafter, the input shaft portion and the torque sensor are inserted into the input side housing portion. Therefore, when the rotation stopper is provided in the input side housing, the rotation stopper and the torque sensor are aligned and engaged when the input shaft portion and the torque sensor are inserted into the input housing.

  The opening of the input side housing part is closed by the retainer plate as the input shaft part and the torque sensor are inserted into the input side housing part. It is difficult to match the positions of the rotation stop portion and the torque sensor with the input side housing portion being almost closed and to engage them, and the assembly work of the electric power steering apparatus becomes complicated.

  An object of the present invention is to improve the assemblability of an electric power steering apparatus.

  A first invention includes a housing, and a rotation preventing portion that engages with the torque sensor and restricts relative rotation of the torque sensor with respect to the housing, and the housing rotatably supports the input shaft; A second housing fastened to the first housing and rotatably supporting the output shaft; an intermediate portion sandwiched between the first housing and the second housing; and a rotation stopping portion provided at the intermediate portion. Features.

  In the first invention, the rotation preventing portion is provided in an intermediate portion sandwiched between the first housing and the second housing. Therefore, the first housing and the second housing may be fastened after the rotation stopper is engaged with the torque sensor. Therefore, the rotation stopper can be engaged with the torque sensor with the rotation stopper and the torque sensor exposed.

  The second invention is characterized in that the output shaft is rotatably supported by the second housing via the bearing, and the bearing is supported by the intermediate portion.

  In the second invention, since the bearing is supported by the intermediate portion, it is not necessary to provide a member for supporting the bearing separately from the intermediate portion in the electric power steering apparatus. Therefore, the number of parts of the electric power steering device can be reduced, and the assemblability of the electric power steering device can be further improved.

  The third invention is characterized in that the intermediate portion is fitted to the outer peripheral surface of the bearing.

  In the third invention, since the intermediate portion is fitted to the outer peripheral surface of the bearing, the intermediate portion does not rattle in the radial direction even before the first housing and the second housing are fastened. Therefore, the assemblability of the electric power steering device can be further improved.

  According to a fourth aspect of the present invention, the intermediate portion includes an annular portion having a contact surface that contacts the opening end surface of the second housing, and a recess portion that opens to the contact surface of the annular portion, and the rotation stopper portion is the recess portion. It is characterized by being fixed to the intermediate portion through a claw portion inserted through the hole formed in the recess and fixed in the hollow portion.

  In the fourth aspect of the invention, the claw portion is fixed in the recessed portion that opens to the contact surface of the annular portion, so that the claw portion is not caught on the opening end surface of the second housing. Therefore, in a state where the first housing and the second housing are not fastened, the relative rotation of the intermediate portion and the torque sensor with respect to the second housing is not hindered. Therefore, after the output shaft is assembled in the second housing, the intermediate portion and the torque sensor can be relatively rotated with respect to the second housing for alignment, and the assemblability of the electric power steering apparatus can be further improved.

  ADVANTAGE OF THE INVENTION According to this invention, the assembly property of an electric power steering apparatus can be improved.

It is a lineblock diagram of an electric power steering device concerning an embodiment of the present invention. 1 is a perspective view of an electric power steering device according to an embodiment of the present invention. 1 is a cross-sectional view of an electric power steering device according to an embodiment of the present invention. It is a disassembled perspective view of the electric power steering device which concerns on embodiment of this invention, and shows the state which removed the 1st housing from the 2nd housing. It is a disassembled perspective view of the electric power steering device which concerns on embodiment of this invention, and shows the state which removed the assembly from the 2nd housing. It is sectional drawing of the electric power steering apparatus which concerns on embodiment of this invention, and shows the state which removed the assembly from the 2nd housing. It is the perspective view which looked at the intermediate part from the upper part. It is the perspective view which looked at the middle part from the lower part. It is a perspective view of a middle part and a rotation stop part, and shows the state where a rotation stop part was removed from a middle part.

  Hereinafter, an electric power steering apparatus 100 according to an embodiment of the present invention will be described with reference to the drawings.

  The electric power steering device 100 is a device that is mounted on a vehicle and assists the steering of the steering wheel 1 by a driver.

  In the present embodiment, a dual pinion type electric power steering apparatus 100 in which a steering torque by a driver and a steering assist torque by the electric motor 21 are independently input to the rack shaft 12 will be described.

  First, the overall configuration of the electric power steering apparatus 100 will be described with reference to FIG.

  The electric power steering apparatus 100 is input through the steering wheel 1 by a steering mechanism 10 that steers the wheel 2 according to the rotation of the steering wheel 1 by the steering of the driver, an assist mechanism 20 that assists the steering of the driver, and the driver. A torque sensor 40 for detecting the steering torque and a controller 30 for controlling the driving of the electric motor 21 based on the detection result of the torque sensor 40.

  The steered mechanism 10 includes a steering shaft 11 that is connected to the steering wheel 1 and rotates according to the rotation of the steering wheel 1, and a rack shaft 12 that steers the wheels 2 according to the rotation of the steering shaft 11.

  The steering shaft 11 includes an input shaft 13 that rotates as the steering wheel 1 is steered by a driver, an output shaft 15 that is linked to a rack shaft 12 that steers the wheel 2, and a torsion that connects the input shaft 13 and the output shaft 15. And a bar 14.

  A first pinion 16 that meshes with a rack 12 a formed on the rack shaft 12 is formed below the output shaft 15. When the steering wheel 1 is steered, the steering shaft 11 is rotated, and the rotation is converted into linear motion of the rack shaft 12 by the first pinion 16 and the rack 12a, and the wheel 2 is steered via the knuckle arm 4. .

  The assist mechanism 20 includes an electric motor 21 that is a power source of steering assist torque, a pinion shaft 22 to which the driving force of the electric motor 21 is transmitted, and a speed reduction mechanism that decelerates the rotation of the electric motor 21 and transmits it to the pinion shaft 22. 3. The speed reduction mechanism 3 includes a worm shaft 3 a connected to the output shaft of the electric motor 21 and a worm wheel 3 b that meshes with the worm shaft 3 a and is connected to the pinion shaft 22.

  A second pinion 23 that meshes with a rack 12 a formed on the rack shaft 12 is formed below the pinion shaft 22. When the electric motor 21 rotates, the pinion shaft 22 rotates through the speed reduction mechanism 3, and the rotation is converted into a linear motion of the rack shaft 12 by the second pinion 23 and the rack 12 a, and steering assist torque is applied to the rack shaft 12. Is done.

  The torque sensor 40 detects the steering torque applied to the torsion bar 14 based on the rotation angle difference between the input shaft 13 and the output shaft 15.

  A control board (not shown) of the torque sensor 40 and the controller 30 are electrically connected via a cable 36 as a signal line. Power is supplied from the controller 30 to the torque sensor 40 through the cable 36, and a steering torque signal detected by the torque sensor 40 is output to the controller 30.

  Next, the structure of the electric power steering apparatus 100 will be described in detail with reference to FIGS.

  As shown in FIGS. 3 to 6, the input shaft 13, the torsion bar 14, the output shaft 15, and the torque sensor 40 are configured as an integral part. Specifically, the input shaft 13 and the output shaft 15 are connected via the torsion bar 14, and the torque sensor 40 is attached across the input shaft 13 and the output shaft 15. The input shaft 13 and the output shaft 15 rotate relative to each other according to the amount of twist of the torsion bar 14, and the torque sensor 40 detects the steering torque based on the rotation angle difference between the input shaft 13 and the output shaft 15 due to the relative rotation. The input shaft 13, the torsion bar 14, the output shaft 15, and the torque sensor 40 are accommodated in the housing 5.

  The torque sensor 40 detects a steering torque and outputs a signal to the controller 30 (see FIG. 1). The case main body 41 houses a control board, and a protrusion 42 projects radially from the outer peripheral surface 41a of the case main body 41. And a connector 43 to which the cable 36 (see FIG. 1) is connected. The case body 41 has a substantially annular shape through which the input shaft 13 is inserted, and is provided rotatably on the outer peripheral surface of the input shaft 13.

  The connector 43 is a female connector having a mounting opening 43a into which a male connector (not shown) provided at the tip of the cable 36 is inserted. The connector 43 is disposed on the upper surface of the case main body 41 so that the attachment port 43 a faces the inner surface of the housing 5.

  The housing 5 includes a first housing 50 that rotatably supports the input shaft 13, a second housing 60 that rotatably supports the output shaft 15, and an intermediate portion sandwiched between the first housing 50 and the second housing 60. 70. The first housing 50 is fastened to the second housing 60 using bolts 91 as fastening members (see FIG. 2).

  The first housing 50 includes a small-diameter portion 51, a large-diameter portion 52 having an inner diameter larger than that of the small-diameter portion 51, and a flange portion 53 that protrudes radially outward from the large-diameter portion 52 and is formed in an annular shape. Have. The torque sensor 40 is accommodated in the large diameter portion 52.

  A bush 94 is provided on the inner peripheral surface of the small diameter portion 51. The input shaft 13 is rotatably supported by the first housing 50 via the bush 94. An opening 51 a through which the input shaft 13 is inserted is formed on the end surface of the small diameter portion 51. Inside the small diameter portion 51, a seal member 95 that prevents foreign matter from entering the inside through the opening 51 a is provided along with the bush 94.

  The large-diameter portion 52 has a window portion 55 formed so as to protrude radially outward from the outer peripheral surface 52a. The window portion 55 is formed with a through hole 55 a that penetrates in the radial direction of the large diameter portion 52 and draws the cable 36 into the first housing 50. A cable holder 38 that holds the cable 36 is fastened to the window portion 55 via a bolt 39. An O-ring 93 is interposed between the window 55 and the cable holder 38 to prevent rainwater and muddy water from entering the housing 5.

  The flange portion 53 has a fastening portion 54 to which the bolt 91 is fastened. The fastening portion 54 is formed to protrude radially outward from the outer peripheral surface of the flange portion 53.

  The second housing 60 is formed integrally with the rack housing 90 that houses the rack shaft 12. The second housing 60 and the rack housing 90 may be formed separately.

  The second housing 60 includes a large diameter portion 61, a medium diameter portion 62 having a smaller inner diameter than the large diameter portion 61, and a small diameter portion 63 having a smaller inner diameter than the medium diameter portion 62. The large-diameter portion 61 has a fastening portion 68 that is formed to protrude radially outward from the outer peripheral surface 61a and to which the bolt 91 is fastened.

  The large diameter portion 61 accommodates a ball bearing 96 as a bearing. A step portion 61b is formed on the inner peripheral surface of the large diameter portion 61, and an outer ring of a ball bearing 96 is locked to the step portion 61b. The inner diameter of the large diameter portion 61 is substantially equal to the outer diameter of the ball bearing 96, and the large diameter portion 61 is fitted to the outer peripheral surface of the ball bearing 96.

  A step portion 15a is formed on the upper portion of the output shaft 15, and the inner ring of the ball bearing 96 is locked to the step portion 15a. A caulking ring 17 is provided on the outer peripheral surface of the output shaft 15 at a distance from the step portion 15a. The inner ring of the ball bearing 96 is sandwiched between the step portion 15 a and the caulking ring 17. That is, the inner ring of the ball bearing 96 is fixed to the output shaft 15 by the caulking ring 17.

  Since the outer ring of the ball bearing 96 is fixed to the second housing 60 and the inner ring of the ball bearing 96 is fixed to the output shaft 15, the upper side of the output shaft 15 can freely rotate to the second housing 60 via the ball bearing 96. Supported.

  The middle diameter portion 62 of the second housing 60 is formed so as to surround the first pinion 16 formed on the output shaft 15. The middle diameter portion 62 is formed with an opening 62 a that communicates with the inside of the rack housing 90. The first pinion 16 and the rack 12a (see FIG. 1) of the rack shaft 12 mesh with each other through the opening 62a.

  The lower end portion of the small diameter portion 63 of the second housing 60 is closed, and a needle bearing 97 as a bearing is accommodated in the small diameter portion 63. The outer ring of the needle bearing 97 is fitted to the inner peripheral surface of the small diameter portion 63, and the needle roller of the needle bearing 97 is in contact with the lower side of the output shaft 15. Thus, the lower side of the output shaft 15 is rotatably supported by the second housing 60 via the needle bearing 97.

  The intermediate portion 70 protrudes radially outward from the annular portion 71 that contacts the opening end surface 61 c of the large-diameter portion 61, the outer cylindrical portion 72 provided on the outer peripheral edge of the annular portion 71, and the tip of the outer cylindrical portion 72. And an outer flange 73 formed in an annular shape. The outer flange 73 has an insertion part 74 that protrudes radially outward from the outer peripheral end and through which the bolt 91 is inserted.

  The first housing 50 and the second housing 60 are fixed by a bolt 91 that is fastened across the fastening portions 54 and 68 with the intermediate portion 70 sandwiched therebetween. Specifically, the flange portion 53 of the first housing 50 and the outer flange 73 of the intermediate portion 70 are in contact with each other, and the opening end surface 61c of the second housing 60 and the annular portion 71 of the intermediate portion 70 are in contact with each other. In the state, the first housing 50 and the second housing 60 are fixed.

  The intermediate portion 70 is fixed between the first housing 50 and the second housing 60 by a bolt 91 that passes through the insertion portion 74. Therefore, it is not necessary to provide a member for fixing the intermediate portion 70 to the first housing 50 and the second housing 60 in the electric power steering device 100 separately from the bolt 91, and the number of parts of the electric power steering device 100 can be reduced. it can.

  An annular protrusion 56 is formed in the flange portion 53 of the first housing 50 and is located inside the outer cylindrical portion 72 of the intermediate portion 70. Between the outer peripheral surface of the protrusion 56 and the inner peripheral surface of the outer cylinder part 72, an annular O-ring 92a is provided for sealing between the two.

  An annular recess is formed in the opening end surface 61 c of the second housing 60. An O-ring 92 b that seals between the opening end surface 61 c and the annular portion 71 is provided in this recess. The O-ring 92 b is in contact with the outer peripheral surface of the ball bearing 96.

  The intermediate portion 70 includes an inner cylindrical portion 75 as a fitting portion that fits on the outer peripheral surface of the ball bearing 96 and an inner flange portion 76 as a support portion that supports the ball bearing 96. The inner cylinder portion 75 is provided at the inner peripheral end of the annular portion 71. The inner flange 76 protrudes radially inward from the tip of the inner cylinder 75 and is formed in an annular shape. The inner diameter of the inner flange 76 is larger than the outer diameter of the steering shaft 11 (output shaft 15), and the steering shaft 11 is inserted through the inner flange 76.

  The inner cylindrical portion 75 has an inner diameter that is substantially equal to the outer diameter of the ball bearing 96. Therefore, in a state where the inner cylindrical portion 75 is fitted to the outer peripheral surface of the ball bearing 96, the intermediate portion 70 is in the radial direction of the steering shaft 11 even before the first housing 50 and the second housing 60 are fastened. I can't play. Therefore, the assemblability of the electric power steering apparatus 100 can be improved.

  The inner flange 76 has a smaller inner diameter than the outer diameter of the outer ring of the ball bearing 96, and the outer ring of the ball bearing 96 is sandwiched between the step portion 61 b of the second housing 60 and the inner flange 76. Therefore, the movement of the ball bearing 96 in the axial direction of the output shaft 15 with respect to the second housing 60 is restricted.

  As shown in FIGS. 4, 5, and 8, the intermediate portion 70 is provided with a rotation stopper 80 that restricts relative rotation of the torque sensor 40 with respect to the second housing 60. The rotation stopper 80 includes a base 81 and two engagement pins 82 and 83 extending from the base 81 in the axial direction of the steering shaft 11.

  The interval between the two engagement pins 82 and 83 is set to be substantially the same as the width of the protrusion 42 of the torque sensor 40. By inserting the protrusion 42 between the engagement pins 82 and 83, the rotation stopper 80 is engaged with the torque sensor 40.

  The rotation stopper 80 further includes claw portions 84 and 85 that pass through the holes 70a and 70b of the intermediate portion 70 (see FIG. 8). The rotation preventing portion 80 is fixed to the intermediate portion 70 by caulking the claw portions 84 and 85 inserted through the holes 70a and 70b. FIG. 8 shows the claws 84 and 85 before being crimped.

  Since the rotation stopper 80 is fixed to the intermediate portion 70, the rotation sensor 80 is engaged with the torque sensor 40 and the intermediate portion 70 is fixed to the second housing 60. Relative rotation is restricted.

  In the present embodiment, the rotation stopper 80 is provided in the intermediate portion 70. Therefore, after the rotation stopper 80 is engaged with the torque sensor 40, the first housing 50 and the second housing 60 are fastened so that the opening of the first housing 50 is closed with the intermediate portion 70 and the second housing 60. Good. Before the opening of the first housing 50 is closed, that is, with the rotation stopper 80 and the torque sensor 40 exposed, the rotation stopper 80 and the torque sensor 40 can be aligned and engaged with each other. Assembling property of the electric power steering apparatus 100 can be improved.

  In addition, since the ball bearing 96 is supported by the inner flange portion 76 of the intermediate portion 70, it is not necessary to provide a member for supporting the ball bearing 96 in the electric power steering apparatus 100 separately from the intermediate portion 70. Therefore, the number of parts of the electric power steering apparatus 100 can be reduced, and the assemblability of the electric power steering apparatus 100 can be further improved.

  The intermediate portion 70 is formed with a recess 77 that opens on a contact surface 71a (the lower surface of the annular portion 71) that contacts the opening end surface 61c of the second housing 60 (see FIG. 7B). Specifically, the depression 77 is formed by pressing the plate-like annular portion 71 to form a projection 78 on the annular portion 71. The rotation stopper 80 is attached to the tip surface 78 a of the protrusion 78.

  The holes 70 a and 70 b of the intermediate portion 70 are formed in the recess portion 77. The claw portions 84 and 85 of the rotation stopper 80 are fixed in the recess 77. Therefore, the claw portions 84 and 85 are not caught on the opening end surface 61 c of the second housing 60. That is, when the first housing 50 and the second housing 60 are not fastened, the relative rotation of the intermediate portion 70 and the torque sensor 40 with respect to the second housing 60 is not hindered. Therefore, after the output shaft 15 is incorporated in the second housing 60, the circumferential positions of the intermediate portion 70, the torque sensor 40, and the second housing 60 can be matched, and the assembly of the electric power steering apparatus 100 can be further improved. Can do.

  Below, with reference to FIGS. 2-6, the assembly method of the electric power steering apparatus 100 is demonstrated.

  As shown in FIGS. 5 and 6, the input shaft 13, the torsion bar 14, the output shaft 15, the torque sensor 40, the intermediate portion 70, the rotation stopper 80 and the ball bearing 96 are assembled before being housed in the housing 5, Assemble one-piece assembly 7. The assembly procedure of the assembly 7 will be specifically described.

  First, the input shaft 13, the torsion bar 14, and the output shaft 15 are assembled, and the steering shaft 11 is assembled. The lower part of the steering shaft 11 (output shaft 15) is passed through the ball bearing 96 and the caulking ring 17, and the caulking ring 17 is attached to the output shaft 15 so that the ball bearing 96 is sandwiched between the step portion 15a of the output shaft 15 and the caulking ring 17. Fix it.

  Next, the upper part of the steering shaft 11 (input shaft 13) is passed through the intermediate part 70, and the inner cylindrical part 75 of the intermediate part 70 is fitted to the outer peripheral surface of the ball bearing 96. As a result, rattling of the intermediate portion 70 in the radial direction of the steering shaft 11 is prevented. The rotation stopper 80 is fixed to the intermediate portion 70 by passing the claw portions 84 and 85 through the holes 70a and 70b of the intermediate portion 70 and caulking the claw portions 84 and 85 in advance (see FIG. 8).

  Next, the upper part of the steering shaft 11 (input shaft 13) is passed through the torque sensor 40. At this time, the protrusion 42 of the torque sensor 40 is inserted between the engagement pins 82 and 83 of the rotation stopper 80, and the rotation stopper 80 is engaged with the torque sensor 40. Since the rotation stopper 80 and the torque sensor 40 are exposed, the rotation stopper 80 can be easily engaged with the torque sensor 40. Further, since the inner cylindrical portion 75 of the intermediate portion 70 is fitted to the outer peripheral surface of the ball bearing 96, the intermediate portion 70 and the rotation stopper 80 do not rattle in the radial direction, and the rotation stopper 80 is attached to the torque sensor 40. It can be easily engaged.

  The assembly 7 is assembled by the above procedure.

  Next, the assembly 7 is assembled in the second housing 60. Specifically, the assembly 7 is inserted into the second housing 60 through the opening of the large diameter portion 61, and the output shaft 15 is inserted into the needle bearing 97 accommodated in the small diameter portion 63. At this time, the assembly 7 is rotated and inserted into the second housing 60 so that the first pinion 16 of the output shaft 15 meshes with the rack 12a of the rack shaft 12 (see FIG. 1).

  Next, the intermediate portion 70, the rotation stop portion 80, and the torque sensor 40 are rotated relative to the second housing 60 to align the positions of the fastening portion 68 of the second housing 60 and the insertion portion 74 of the intermediate portion 70. Thereby, the torque sensor 40 is arranged at a predetermined position.

  Since the claw portions 84 and 85 of the rotation stopper 80 are fixed in the recess portion 77, the claw portions 84 and 85 are not caught by the opening end surface 61 c of the second housing 60, and the intermediate portion 70 and the second housing 60. The relative rotation of the torque sensor 40 is not hindered. Therefore, the positions of the intermediate portion 70 and the torque sensor 40 and the second housing 60 can be easily matched.

  Next, as shown in FIG. 4, the first housing 50 is placed on the outer flange 73 of the intermediate portion 70 so as to cover the torque sensor 40 from above the steering shaft 11. Thereafter, as shown in FIG. 2, the first housing 50 and the second housing 60 are fastened by using bolts 91. Accordingly, the intermediate portion 70 is sandwiched between the first housing 50 and the second housing 60, the relative rotation of the intermediate portion 70 with respect to the second housing 60 is restricted, and the relative rotation of the torque sensor 40 with respect to the housing 5 is restricted.

  As shown in FIG. 3, the ball bearing 96 is supported by the inner flange portion 76 of the intermediate portion 70 when the intermediate portion 70 is sandwiched between the first housing 50 and the second housing 60. Therefore, the movement of the ball bearing 96 with respect to the second housing 60 is restricted, and the movement of the steering shaft 11 with respect to the housing 5 is restricted.

  According to the above embodiment, there exist the effects shown below.

  Since the rotation stopper 80 is provided in the intermediate portion 70, the first housing 50 and the second housing 60 may be fastened after the rotation stopper 80 is engaged with the torque sensor 40. Since the rotation stopper 80 and the torque sensor 40 are exposed before the first housing 50 and the second housing 60 are fastened, the rotation stopper 80 can be easily engaged with the torque sensor 40. Therefore, the assemblability of the electric power steering apparatus 100 can be improved.

  Since the ball bearing 96 is supported by the inner flange portion 76 of the intermediate portion 70, it is not necessary to provide a member for supporting the ball bearing 96 in the electric power steering apparatus 100 separately from the intermediate portion 70. Therefore, the number of parts of the electric power steering apparatus 100 can be reduced, and the assemblability of the electric power steering apparatus 100 can be further improved.

  In addition, since the inner cylindrical portion 75 of the intermediate portion 70 is fitted to the outer peripheral surface of the ball bearing 96 before the rotation stopper 80 is engaged with the torque sensor 40, the rotation stopper 80 is engaged with the torque sensor 40. Further, the intermediate portion 70 and the rotation stopper 80 do not rattle. Therefore, the rotation stopper 80 can be easily engaged with the torque sensor 40, and the assemblability of the electric power steering apparatus 100 can be further improved.

  Since the claw portions 84 and 85 of the rotation stop portion 80 are fixed in the recess portion 77, before the intermediate portion 70 is fixed to the second housing 60, the intermediate portion 70 and the torque sensor 40 with respect to the second housing 60. Relative rotation is not hindered. Therefore, the positions of the intermediate portion 70 and the torque sensor 40 and the second housing 60 can be easily matched, and the assemblability of the electric power steering apparatus 100 can be further improved.

  Hereinafter, the configuration, operation, and effect of the embodiment of the present invention will be described together.

  In the present embodiment, the electric power steering apparatus 100 includes an input shaft 13 to which a steering torque is input, an output shaft 15 connected to the input shaft 13 via a torsion bar 14, and the input shaft 13 and the output shaft 15. And a torque sensor 40 that detects steering torque, a housing 5 that houses the input shaft 13, the output shaft 15, and the torque sensor 40, and a relative rotation of the torque sensor 40 with respect to the housing 5 by engaging with the torque sensor 40. The housing 5 includes a first housing 50 that rotatably supports the input shaft 13, and a second housing that is fastened to the first housing 50 and rotatably supports the output shaft 15. It is sandwiched between the housing 60, the first housing 50 and the second housing 60. By having an intermediate portion 70, a rotation stopper 80 is provided in the intermediate portion 70.

  In this configuration, the rotation stopper 80 is provided in the intermediate part 70 sandwiched between the first housing 50 and the second housing 60. Therefore, the first housing 50 and the second housing 60 may be fastened after the rotation stopper 80 is engaged with the torque sensor 40. Therefore, the rotation stopper 80 can be engaged with the torque sensor 40 in a state where the rotation stopper 80 and the torque sensor 40 are exposed, and the assemblability of the electric power steering apparatus 100 can be improved.

  In this embodiment, the output shaft 15 is rotatably supported by the second housing 60 via the ball bearing 96, and the ball bearing 96 is supported by the intermediate portion 70.

  In this configuration, since the ball bearing 96 is supported by the intermediate portion 70, it is not necessary to provide a member for supporting the ball bearing 96 in the electric power steering apparatus 100 separately from the intermediate portion 70. Therefore, the number of parts of the electric power steering apparatus 100 can be reduced, and the assemblability of the electric power steering apparatus 100 can be further improved.

  In the present embodiment, the intermediate portion 70 is fitted to the outer peripheral surface of the ball bearing 96.

  In this configuration, since the intermediate portion 70 is fitted to the outer peripheral surface of the ball bearing 96, the intermediate portion 70 rattles in the radial direction even before the first housing 50 and the second housing 60 are fastened. Absent. Therefore, the assemblability of the electric power steering apparatus 100 can be further improved.

  In the present embodiment, the intermediate portion 70 includes an annular portion 71 having a contact surface 71a that contacts the opening end surface 61c of the second housing 60, and a hollow portion 77 that opens to the contact surface 71a of the annular portion 71. The rotation stopper 80 is fixed to the intermediate portion 70 via claw portions 84 and 85 that are inserted into holes 70 a and 70 b formed in the recess 77 and fixed in the recess 77.

  In this configuration, the claw portions 84 and 85 are fixed in the hollow portion 77 that opens to the contact surface 71 a of the annular portion 71, so that the claw portions 84 and 85 are not caught by the opening end surface 61 c of the second housing 60. Therefore, in a state where the first housing 50 and the second housing 60 are not fastened, the relative rotation of the intermediate portion 70 and the torque sensor 40 with respect to the second housing 60 is not hindered. Therefore, the position of the intermediate portion 70 and the second housing 60 can be adjusted after the output shaft 15 is incorporated into the second housing 60, and the assemblability of the electric power steering apparatus 100 can be further improved.

  The embodiment of the present invention has been described above. However, the above embodiment only shows a part of application examples of the present invention, and the technical scope of the present invention is limited to the specific configuration of the above embodiment. Absent.

  (1) The torque sensor 40 may be configured to have a function of an angle sensor that detects the absolute rotation angle of the steering shaft 11. That is, the torque sensor 40 may be a torque angle sensor.

  (2) In the above embodiment, the pinion type electric power steering apparatus 100 in which the first pinion 16 that meshes with the rack 12 a formed on the rack shaft 12 is formed on the output shaft 15 has been described. However, the present invention may be a column type electric power steering apparatus in which no pinion is formed on the output shaft 15.

  (3) In the above embodiment, the dual pinion type electric power steering apparatus 100 in which the steering torque by the driver and the steering assist torque by the electric motor 21 are independently input to the rack shaft 12 has been described. However, the present invention may be a single pinion type electric power steering apparatus in which the steering torque by the driver and the steering assist torque by the electric motor 21 are input to the rack shaft 12 via a common steering shaft. In that case, the assist mechanism 20 is provided on the output shaft 15.

  (4) The rotation stopper 80 is engaged with the torque sensor 40 by inserting the protrusion 42 of the torque sensor 40 between the two engagement pins 82 and 83. However, the rotation stopper 80 may have a single engaging pin, and may be configured to engage with the torque sensor 40 by inserting the engaging pin into a groove formed in the torque sensor 40.

  (5) The rotation preventing portion 80 is fixed to the intermediate portion 70 by caulking the claw portions 84 and 85. However, the rotation stopper 80 may be fixed to the intermediate portion 70 by inserting a plug into the recess 77 and engaging the claw portions 84 and 85 with the plug. Further, the rotation stopper 80 may be fixed to the intermediate portion 70 using an adhesive.

  (6) The intermediate portion 70 and the rotation stopper 80 are formed as separate bodies and are fixed to each other via the claw portions 84 and 85. However, the intermediate part 70 and the rotation stopper 80 may be formed integrally.

  (7) In the above embodiment, the assembly method for incorporating the steering shaft 11 into the second housing 60 after engaging the rotation stopper 80 with the torque sensor 40 has been described. However, the rotation stopper 80 may be engaged with the torque sensor 40 after the steering shaft 11 is incorporated into the second housing 60.

  DESCRIPTION OF SYMBOLS 100 ... Electric power steering apparatus, 5 ... Housing, 13 ... Input shaft, 14 ... Torsion bar, 15 ... Output shaft, 40 ... Torque sensor, 50 ... 1st housing 60 ... second housing, 61c ... open end surface, 70 ... intermediate portion, 70a, 70b ... hole, 71 ... annular portion, 71a ... contact surface, 77 ... dent , 80... Anti-rotation part, 84, 85 .. Claw part, 96... Ball bearing (bearing)

Claims (4)

An electric power steering device,
An input shaft to which steering torque is input;
An output shaft connected to the input shaft via a torsion bar;
A torque sensor mounted across the input shaft and the output shaft and detecting the steering torque;
A housing that houses the input shaft, the output shaft, and the torque sensor;
A rotation stopper that engages with the torque sensor and restricts relative rotation of the torque sensor with respect to the housing;
The housing is
A first housing that rotatably supports the input shaft and covers the torque sensor;
A second housing fastened to the first housing and rotatably supporting the output shaft;
An intermediate portion sandwiched between the first housing and the second housing,
The electric power steering device according to claim 1, wherein the rotation stopper is provided in the intermediate portion. The output shaft is rotatably supported by the second housing via a bearing,
The electric power steering apparatus according to claim 1, wherein the bearing is supported by the intermediate portion.   The electric power steering apparatus according to claim 2, wherein the intermediate portion is fitted to an outer peripheral surface of the bearing. The intermediate portion includes an annular portion having a contact surface that contacts an opening end surface of the second housing, and a recess portion that opens to the contact surface of the annular portion,
The said rotation stop part is fixed to the said intermediate part through the nail | claw part which penetrated the hole formed in the said hollow part, and was fixed in the said hollow part, The any one of Claim 1 to 3 characterized by the above-mentioned. The electric power steering device according to the item.

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