JP6589390B2 - Electric power steering device - Google Patents

Description

  The present invention relates to an electric power steering apparatus that applies a rotational force of an electric motor as a steering assist force to a steering mechanism of a vehicle.

  2. Description of the Related Art Conventionally, in an electric power steering apparatus having an electric motor, a gear mechanism that decelerates the rotational force of the electric motor and transmits it as a steering assist force to a steering mechanism, and a gear housing that houses the gear mechanism, the vibration of the electric motor is a gear. There is one provided with a vibration absorbing member for suppressing transmission to the housing (see Patent Documents 1 and 2).

  In the electric power steering device described in Patent Document 1, a mount bush as a vibration absorbing member is fitted into a through hole formed in a flange portion of the electric motor, and the electric motor is attached to the gear housing via the mount bush. ing. The mount bush has a metal cylindrical member and an elastic body disposed on the outer periphery of the cylindrical member, and a bolt that passes through the cylindrical member is screwed into the gear housing.

  In the electric power steering apparatus described in Patent Document 2, a metal plate as a vibration absorbing member is sandwiched between a motor housing that houses an electric motor and a gear housing. The metal plate is made of iron-based material in which spheroidal graphite is formed, such as spheroidal graphite cast iron, or metal material such as aluminum alloy or magnesium alloy having acicular voids, and is attenuated by spheroidal graphite or acicular voids. It is comprised so that an effect may be exhibited.

  According to the electric power steering apparatus described in Patent Literatures 1 and 2, the vibration of the electric motor is suppressed from being transmitted to the gear housing, and the vibration and noise generated with the rotation of the electric motor can be reduced. It becomes possible.

JP-A-11-198829 JP 2006-232062 A

  In the electric power steering devices described in Patent Documents 1 and 2, the vibration absorbing member suppresses the vibration of the electric motor from being transmitted to the gear housing. In order to provide the vibration absorbing member, the electric power steering is provided. This leads to an increase in the number of parts and assembly man-hours of the apparatus. Moreover, it is contrary to the weight reduction of the apparatus, and may hinder the improvement of the fuel consumption performance of the vehicle.

  Therefore, the present invention provides an electric power steering device capable of suppressing the vibration of the electric motor from being transmitted to the housing that houses the gear mechanism without adding a member that absorbs the vibration of the electric motor. For the purpose.

In order to achieve the above object, the present invention provides an electric motor, a gear mechanism that transmits the rotational force of the electric motor to a shaft that constitutes a steering mechanism as a steering assist force, and a first housing that houses the electric motor. A second housing that houses the gear mechanism, each of the first housing and the second housing having a cylindrical portion and a flange portion protruding from an outer peripheral surface of the cylindrical portion, The flange portions are fastened together by bolts, and the flange portions are fastened to the peripheral portions of the hole portions through which the bolts are inserted or screwed together. At least one of the flange portion of the second housing, between the hole and the front Symbol cylindrical portion, thinned-out part to cross the flange portion is formed To provide an electric power steering device.

  According to the electric power steering apparatus of the present invention, it is possible to suppress the vibration of the electric motor from being transmitted to the housing that houses the gear mechanism without adding a member that absorbs the vibration of the electric motor. .

1 is a schematic diagram illustrating a configuration example of an electric power steering device and a steering mechanism according to a first embodiment of the present invention. It is a block diagram which shows an electric power steering apparatus and its peripheral part. It is a block diagram which shows an electric motor, a motor housing, a gear mechanism, and a gear housing. It is a perspective view which shows a gear housing. (A) is the front view which looked at the 1st accommodating part of the gear housing from the large diameter cylindrical part side. (B) is sectional drawing of the gear housing and motor housing in the AA of (a). It is a block diagram which shows the motor housing and gear housing of the electric power steering apparatus which concern on the 2nd Embodiment of this invention. It is sectional drawing which shows the flange part of the motor housing and gear housing which concern on the 2nd Embodiment of this invention.

[First Embodiment]
A first embodiment of the present invention will be described with reference to FIGS. Note that the embodiment described below is shown as a preferred specific example when the electric power steering apparatus of the present invention is implemented, and specifically illustrates various technical matters that are technically preferable. However, the technical scope of the present invention is not limited to this embodiment.

  FIG. 1 is a schematic diagram illustrating a configuration example of an electric power steering apparatus according to an embodiment of the present invention and a steering mechanism to which a steering assist force is applied by the electric power steering apparatus.

  The steering mechanism 1 includes a steering wheel 11 that is rotated by a driver, a steering shaft 12 that is coupled to the steering wheel 11, and a rack shaft 13 that extends in the vehicle width direction of the vehicle. The steering shaft 12 includes a column shaft 121 to which the steering wheel 11 is fixed at one end, a pinion shaft 123 having pinion teeth 123 a that mesh with the rack teeth 13 a of the rack shaft 13, and the column shaft 121 and the pinion shaft 123. And an intermediate shaft 122 interposed.

  The column shaft 121 includes an upper shaft 121a and a lower shaft 121b, and the upper shaft 121a and the lower shaft 121b are connected by a torsion bar 140 of the torque sensor 14. The torque sensor 14 detects the steering torque applied to the steering wheel 11 by the driver based on the twist of the torsion bar 140.

  The column shaft 121 and the intermediate shaft 122 are connected by a universal joint 124, and the intermediate shaft 122 and the pinion shaft 123 are connected by a universal joint 125. The column shaft 121, the intermediate shaft 122, the pinion shaft 123, and the rack shaft 13 are each an aspect of a shaft that constitutes the steering mechanism 1.

  The rack shaft 13 is accommodated in a cylindrical rack housing 15 so as to be movable in the axial direction. The rack shaft 13 is formed with rack teeth 13 a made of oblique teeth along the axial direction thereof, and the rack teeth 13 a mesh with the pinion teeth 123 a of the pinion shaft 123. Ball joint sockets 16 are fixed to both ends of the rack shaft 13, and tie rods 17 connected to these ball joint sockets 16 are connected to the left and right steered wheels 19 through knuckle arms (not shown). A boot 18 made of bellows-like rubber or resin is disposed on the outer peripheral side of the ball joint socket 16.

  When the steering wheel 11 is rotated, the pinion shaft 123 connected to the steering wheel 11 via the column shaft 121 and the intermediate shaft 122 rotates, and the rack shaft 13 is rotated by the meshing of the pinion teeth 123a and the rack teeth 13a. Move linearly in the axial direction. Due to the linear motion of the rack shaft 13, the left and right steered wheels 19 are steered through the tie rods 17.

  The electric power steering apparatus 10 includes an electric motor 2, a gear mechanism 3 that transmits the rotational force of the electric motor 2 to a shaft constituting the steering mechanism 1 as a steering assist force, and a motor housing (described later) that houses the electric motor 2. And a gear housing (described later) for housing the gear mechanism 3 and a controller 4 for controlling the electric motor 2.

  In the present embodiment, the gear mechanism 3 is a worm gear mechanism including a worm 31 coupled to the output rotation shaft of the electric motor 2 and a worm wheel 32 that rotates integrally with the lower shaft 121b. The controller 4 controls the electric motor 2 by supplying a motor current to the electric motor 2 based on the vehicle speed and the steering torque detected by the torque sensor 14.

  FIG. 2 is a configuration diagram showing the motor housing 6 and the gear housing 7 of the electric power steering apparatus 10 and the peripheral portion thereof. FIG. 3 is a configuration diagram showing the electric motor 2, the motor housing 6, the gear mechanism 3, and the worm housing 70 of the gear housing 7. FIG. 4 is a perspective view showing the worm housing 70. The motor housing 6 is an aspect of the first housing of the present invention, and the gear housing 7 is an aspect of the second housing of the present invention.

  The upper shaft 121a is accommodated in the cylindrical steering column 5 except for its tip, and is rotatably supported. The steering wheel 11 is fixed to the tip of the upper shaft 121a so as not to be relatively rotatable.

  The steering column 5 includes an outer tube 51 and an inner tube 52, and the outer tube 51 can move relative to the inner tube 52 along the axial direction thereof. The outer tube 51 is supported by a vehicle body (not shown) via a bracket 53. The bracket 53 is in a locked state in which the outer tube 51 is locked (fixed in position) with respect to the vehicle body by a cam mechanism that is operated by the operation of the operation lever 54 by the driver, and the outer tube 51 can be moved in the vertical direction and the inner tube 52. On the other hand, it is possible to switch the unlocked state in which the axial movement is possible. In this unlocked state, the driver can perform tilt adjustment and telescopic adjustment.

  The electric motor 2 is accommodated in the motor housing 6. The motor housing 6 includes a base housing 60 and a bottomed cylindrical cover housing 600 that covers an upper portion of the base housing 60, and is configured by fastening the base housing 60 and the cover housing 600 with a plurality of bolts 601. Yes. As shown in FIG. 3, the base housing 60 includes a cylindrical portion 61 formed in a cylindrical shape, and a plurality (two in the present embodiment) of flange portions 62 that protrude from the outer peripheral surface 61 a of the cylindrical portion 61. The bottom portion 63 is provided so as to cover the opening opposite to the cover housing 600 side. The base housing 60 and the cover housing 600 are formed by aluminum die casting.

  The electric motor 2 includes a shaft 20 that is an output rotation shaft, a rotor 21 that rotates integrally with the shaft 20, and a stator 22 that is fixed to the cover housing 600. The stator 22 includes a cylindrical stator core 220, an insulator 221 inserted into the stator core 220, and a coil 222 wound around the insulator 221. In the stator 22, the stator core 220 is fixed to the cover housing 600 by press fitting, adhesion, or shrink fitting.

  The rotor 21 is disposed inside the stator core 220, and the shaft 20 passes through the axis of the rotor 21. In the rotor 21, a plurality of segment magnets 211 are arranged on the outer peripheral portion facing the stator core 220. The shaft 20 is rotatably supported by a first bearing 231 having an outer ring fixed to the cover housing 600 and a second bearing 232 having an outer ring fixed to the base housing 60, and penetrates the center of the bottom 63 of the base housing 60. is doing.

  A resolver rotor 241 of a resolver 24 that detects the rotational position of the rotor 21 is fixed to the shaft 20 by press-fitting. A resolver stator 242 that surrounds the outer periphery of the resolver rotor 241 is fixed to a recess 63 a formed in the bottom 63 of the base housing 60 by press-fitting.

  The motor housing 6 accommodates a controller 4 that controls the electric motor 2. The controller 4 includes a substrate 40 in which an insertion hole through which the shaft 20 is inserted is formed at the center, and a plurality of electronic components 41 mounted on the substrate 40. The plurality of electronic components 41 include a CPU (Central Processing Unit), an IC such as a memory element, and passive elements such as a resistor and a capacitor. The controller 4 is supplied with a power supply, an output signal of the torque sensor 14 and a signal indicating the vehicle speed from a connector 42 (shown in FIG. 2) disposed exposed from the motor housing 6, and based on the vehicle speed and the steering torque, the resolver 24 The motor current is supplied to the electric motor 2 in consideration of the rotational position of the rotor 21 detected by.

  In the present embodiment, the controller 4 is housed in the motor housing 6. However, the present invention is not limited to this, and the controller 4 may be disposed outside the motor housing 6.

  The gear housing 7 includes a worm housing 70 that houses the gear mechanism 3 and a sensor housing 700 that houses the torque sensor 14 (shown in FIG. 1). The worm housing 70 and the sensor housing 700 are connected by a plurality of bolts 701. It is configured by fastening. An inner tube 52 of the steering column 5 is fastened to the sensor housing 700. As shown in FIG. 4, the worm housing 70 includes a first housing portion 70A in which a housing space 70a for housing the worm 31 is formed, and a second housing portion 70B in which a housing space 70b for housing the worm wheel 32 is formed. Is integrated.

  70 A of 1st accommodating parts are the cylindrical part 71 formed in the cylinder shape, the several flange part 72 which protrudes from the outer peripheral surface 71a of the cylindrical part 71, and the cylindrical part 71. The bottom part 73 which obstruct | occludes the one end part. The cylindrical portion 71 has a small-diameter cylindrical portion 711 whose internal space communicates with the accommodation space 70b of the second accommodation portion 70B via the communication hole 70c, a large-diameter cylindrical portion 713 on the motor housing 6 side, and a small-diameter cylindrical portion 711. And a conical tapered portion 712 whose inner and outer diameters gradually increase from the small diameter cylindrical portion 711 side toward the large diameter cylindrical portion 713 side. The flange portion 72 protrudes from the outer peripheral surface 71 a of the cylindrical portion 71 in the large diameter cylindrical portion 713 and faces the flange portion 62 of the motor housing 6.

  The second housing portion 70B includes a cylindrical portion 74 that houses the worm wheel 32, a flange portion 75 that protrudes from the outer peripheral surface of the cylindrical portion 74, and a bottom portion 76 that is formed with an insertion hole 76a through which the lower shaft 121b is inserted. And have. The flange portion 75 is formed with a screw hole 75 a into which a bolt 701 for fastening the sensor housing 700 is screwed.

  The worm wheel 32 is provided with a tooth portion 321 that meshes with the worm 31 on the outer periphery of a disc-shaped base portion 320. A lower shaft 121b is fitted into a fitting hole 320a formed at the center of the base 320 so as to rotate integrally with the worm wheel 32. The worm 31 is coupled to rotate integrally with the shaft 20 of the electric motor 2. With the above configuration, when the shaft 20 of the electric motor 2 rotates, the worm 31 rotates together with the shaft 20, the rotational force is decelerated and transmitted to the worm wheel 32, and is applied to the lower shaft 121b as a steering assist force.

  The motor housing 6 and the gear housing 7 have cylindrical portions 61 and 71 and flange portions 62 and 72 that protrude from the outer peripheral surfaces 61a and 71a of the cylindrical portions 61 and 71, respectively. And flange portions 62 and 72 are fastened to each other by bolts 602.

  FIG. 5A is a front view of the first housing portion 70A of the gear housing 7 as viewed from the large-diameter cylindrical portion 713 side. In FIG. 5A, the outer peripheral surface 61a of the cylindrical portion 61 of the motor housing 6 is indicated by a two-dot chain line. FIG. 5B is a cross-sectional view of the gear housing 7 and the motor housing 6 taken along line AA in FIG.

  As shown in FIG. 5A, the cylindrical portion 71 of the gear housing 7 and the cylindrical portion 61 of the motor housing 6 have different outer diameters, and the cylindrical portion 71 of the gear housing 7 has a cylindrical shape of the motor housing 6. The outer diameter is smaller than that of the portion 61.

  The flange portion 72 of the gear housing 7 has a substantially triangular shape in a front view shown in FIG. 5A, and a hole portion 72 a into which the bolt 601 is screwed is formed at the distal end portion in the protruding direction from the cylindrical portion 72. Has been. The flange portion 72 of the gear housing 7 is formed with first and second meat stealing portions 72b and 72c that cross the flange portion 72 between the peripheral portion of the hole portion 72a and the tubular portion 71. Yes. In the portion where the first and second meat stealing portions 72b and 72c are formed, the thickness of the flange portion 72 is thin. Hereinafter, the peripheral part of the hole part 72a in which the first and second meat stealing parts 72b and 72c are not formed is referred to as a thick part 721, and the first and second meat stealing parts 72b and 72c are formed. Is referred to as a thin portion 722. In the present embodiment, the thick part 721 is formed in a cylindrical shape having a hole 72a at the center.

  The first and second meat stealing portions 72 b and 72 c cross the flange portion 72 in the circumferential direction of the cylindrical portion 71 of the gear housing 7. Here, the crossing is the first from the one end of the flange portion 72 to the other end in the circumferential direction of the cylindrical portion 71 of the gear housing 7 (the direction orthogonal to the protruding direction of the flange portion 72). The second meat stealing portion 72b, 72c is formed. The 1st meat stealing part 72b is formed in the motor housing 6 side of the thin part 722, and the 2nd meat stealing part 72c is formed in the back side.

As shown in FIG. 5B, the depth of the first meat stealing portion 72b in the thickness direction of the flange portion 72 (the central axis direction of the hole 72a) is d ₁ , and the depth of the second meat stealing portion 72c. the _{d 2,} when the thickness of the thin portion 722 and _{t 2,} d 1, _{d 2,} and _{t 2} are respectively, for example 2.5～3.0Mm. Here, the depth d1 of the _first meat stealing portion 72b is changed from the end surface 721a on the flange portion 62 side of the motor housing 6 in the thick portion 721 to the flat surface 722a on the flange portion 62 side of the motor housing 6 in the thin portion 722. It is the distance to. The depth d2 of the _second meat stealing portion 72c is different from the end surface 721b of the thick portion 721 opposite to the flange portion 62 side of the motor housing 6 from the flange portion 62 side of the motor housing 6 in the thin portion 722. This is the distance to the opposite plane 722b.

Further, assuming that the thickness of the thick portion 721 is t ₁ , the thickness t ₂ of the thin portion 722 is less than or equal to half the thickness t ₁ of the thick portion 721. In this embodiment, the depth d ₁ of the first thinned portion _72b, and the second is the depth d ₂ of the thinned portion 72c is constant, not limited thereto, the first and second The depths d ₁ and d ₂ of the meat stealing portions 72b and 72c may not be constant. However, in any of the sites of the flange portion 72, it is desirable thickness t ₂ of the thin portion 722 is less than half of the thickness t ₁ of the thick portion 721.

  As shown in FIG. 5B, when the cylindrical portion 61 of the motor housing 6 and the cylindrical portion 71 of the gear housing 7 are brought into contact with each other, the hole 62 a formed in the flange portion 62 of the motor housing 6 and the gear A hole portion 72 a formed in the flange portion 72 of the housing 7 communicates. The hole 62a in the flange 62 of the motor housing 6 is formed as a bolt insertion hole not provided with a thread groove, and the male thread of the bolt 602 is screwed into the hole 72a in the flange 72 of the gear housing 7. It is formed as a screw hole. The bolt 602 is inserted through the hole 62 a in the flange portion 62 of the motor housing 6 and screwed into the hole 72 a in the flange portion 72 of the gear housing 7.

  The difference in thickness between the thick part 721 and the thin part 722 is that the length of the hole 72a as a screw hole in the thick part 721 is secured, and the screw thread is crushed by the tightening force of the bolt 602. In consideration of preventing the vibration of the motor housing 6 from being transmitted to the gear housing 7 side even if the motor housing 6 vibrates due to the rotation of the rotor 21 of the electric motor 2 by reducing the rigidity of the thin wall portion 722 while preventing it. It is.

  That is, if the first and second meat stealing portions 72b and 72c are not formed, the vibration transmitted from the flange portion 62 of the motor housing 6 to the flange portion 72 of the gear housing 7 is the cylindrical portion of the gear housing 7. It becomes easy to be transmitted to 71. When vibration is transmitted to the cylindrical portion 71 of the gear housing 7, the vibration is transmitted from the gear housing 7 to the column shaft 121 via the steering column 5, and the steering wheel 11 may vibrate, which may cause discomfort to the driver. There is. Further, if the vibration of the gear housing 7 is transmitted to the vehicle body via the bracket 53 or the like, there is a possibility that a large noise is generated due to resonance or the like.

  On the other hand, in the present embodiment, a thin portion 722 having low rigidity is interposed between the thick portion 721 and the cylindrical portion 71 of the gear housing 7 by forming the first and second meat stealing portions 72b and 72c. Thus, the vibration of the motor housing 6 is hardly transmitted to the cylindrical portion 71 of the gear housing 7. Thereby, it is suppressed that the vibration of the motor housing 6 is transmitted to the column shaft 121 and the vehicle body via the gear housing 7, and the vibration of the steering wheel 11 and noise can be reduced.

(Operation and effect of the first embodiment)
According to the first embodiment described above, the following operations and effects can be obtained.

(1) It is possible to suppress the vibration of the electric motor 2 from being transmitted to the gear housing 7 without adding a member that absorbs the vibration of the electric motor 2 and preventing the number of parts and the number of assembly steps from increasing. It becomes possible. In addition, as the first and second meat stealing portions 72b and 72c are formed, the weight of the device can be reduced.

(2) The first and second meat stealing portions 72 b and 72 c are flange portions 72 provided on the outer peripheral surface 71 a of the cylindrical portion 71 of the gear housing 7 having an outer diameter smaller than that of the cylindrical portion 61 of the motor housing 6. Therefore, the width of the first and second meat stealing portions 72b and 72c in the protruding direction of the flange portion 72 (the radial direction of the tubular portion 71) can be increased. Thereby, the width of the thin portion 722 having a lower rigidity than that of the thick portion 721 can be widened, and the vibration of the electric motor 2 is further hardly transmitted to the gear housing 7.

(3) Since the hole 62a in the flange 62 of the motor housing 6 is formed as a bolt insertion hole, and the hole 72a in the flange 72 of the gear housing 7 is formed as a screw hole, The fastening operation with the gear housing 7 is easy, and the thickness of the thick portion 721 in the flange portion 72 of the gear housing 7 is secured by the thin portion 722 while ensuring that the thread of the hole portion 72a is not crushed. The vibration of the motor 2 can be absorbed.

(4) Thickness _{t 2} of the thin portion 722 of the flange portion 72 of the gear housing 7, since it is less than half of the thickness _{t 1} of the thick portion 721, sufficient effect of absorbing the vibrations of the electric motor 2 by the thin portion 722 It becomes possible to demonstrate to.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIGS. In the first embodiment, the case where the first and second meat stealing portions 72b and 72c are formed in the flange portion 72 of the gear housing 7 has been described. In the second embodiment, the motor housing 6 The flange portion 62 is formed with first and second meat stealing portions 62b and 62c.

  FIG. 6 is a configuration diagram showing the motor housing 6 and the gear housing 7 of the electric power steering apparatus 10 according to the present embodiment. FIG. 7 is a cross-sectional view showing the flange portions 62 and 72 of the motor housing 6 and the gear housing 7. In FIG. 6 and FIG. 7, the same reference numerals as those used in the first embodiment are assigned to the same constituent elements as those described in the first embodiment, and the duplicate description is omitted. To do.

  In the present embodiment, the outer diameter of the cylindrical portion 61 of the motor housing 6 is equal to the outer diameter of the cylindrical portion 71 of the gear housing 7. Further, the meat stealing portion is not formed in the flange portion 72 of the gear housing 7, and the thickness thereof is constant. On the other hand, the flange portion 62 of the motor housing 6 is formed with first and second meat stealing portions 62b and 62c that cross the flange portion 62 between the peripheral portion of the hole portion 62a and the cylindrical portion 61. Yes. In the portion where the first and second meat stealing portions 62b and 62c are formed, the flange portion 62 is thin. Hereinafter, the peripheral portion of the hole 62a where the first and second meat stealing portions 62b and 62c are not formed is referred to as a thick portion 621, and the first and second meat stealing portions 62b and 62c are formed. Is referred to as a thin portion 622. The thick part 621 has a cylindrical shape having a hole 62a at the center. The 1st meat stealing part 62b is formed in the gear housing 7 side of the thin part 622, and the 2nd meat stealing part 62c is formed in the back side.

As shown in FIG. 7B, the depth of the first meat stealing portion 62b in the thickness direction of the flange portion 62 (the central axis direction of the hole 62a) is d ₁ , and the depth of the second meat stealing portion 62c. the _{d 2,} when the thickness of the thin portion 622 and _{t 2,} d 1, _{d 2,} and _{t 2} are respectively, for example 2.5～3.0Mm. Here, the depth d ₁ of the first meat stealing portion 62 b is set such that the flat surface 622 a on the flange portion 72 side of the gear housing 7 in the thin portion 622 from the end surface 621 a on the flange portion 72 side of the gear housing 7 in the thick portion 621. It is the distance to. The depth d2 of the _second meat stealing portion 62c is different from the end surface 621b of the thick wall portion 621 opposite to the flange portion 72 side of the gear housing 7 from the flange portion 72 side of the gear housing 7 of the thin wall portion 622. This is the distance to the opposite plane 622b.

Further, assuming that the thickness of the thick part 621 is t ₁ , the thickness t ₂ of the thin part 622 is less than or equal to half of the thickness t ₁ of the thick part 621. In this embodiment, the depth d ₁ of the first thinned portion _62b, and the second is the depth d ₂ of the thinned portion 62c is constant, not limited thereto, the first and second wall The depths d ₁ and d _{2 of the} stealing portions 62b and 62c may not be constant. However, in any part of the flange portion 62, it is desirable that the thickness t ₂ of the thin portion 622 is less than or equal to half the thickness t ₁ of the thick portion 621.

  Also according to this embodiment, the same operations and effects as those of the first embodiment can be obtained. That is, by forming the first and second meat stealing portions 62 b and 62 c in the flange portion 62 of the motor housing 6, the thin portion 622 having low rigidity between the cylindrical portion 61 and the thick portion 621 of the motor housing 6. As a result, the vibration of the electric motor 2 is made difficult to be transmitted to the gear housing 7, so that the vibration of the electric motor 2 is suppressed from being transmitted to the column shaft 121 and the vehicle body via the gear housing 7. Accordingly, it is possible to suppress the vibration of the electric motor 2 from being transmitted to the gear housing 7 without adding a member that absorbs the vibration of the electric motor 2, thereby reducing the vibration and noise of the steering wheel 11. In addition, the weight of the device can be reduced by forming the first and second meat stealing portions 62b and 62c.

(Appendix)
The electric power steering apparatus of the present invention has been described based on the first and second embodiments. However, the present invention is not limited to these embodiments, and may be appropriately selected without departing from the scope of the present invention. It is possible to carry out a modification. For example, in the first embodiment, the case where the first and second meat stealing portions 72b and 72c are formed on the flange portion 72 of the gear housing 7 has been described. Only one of the stealer 72b and the second meat stealer 72c may be formed. In this case, the configuration in which only the first meat stealing portion 72b is formed is more preferable because the flange portion 72 is more easily deformed than the configuration in which only the second meat stealing portion 72c is formed.

  Similarly, in the second embodiment, the case where the first and second meat stealing portions 62b and 62c are formed in the flange portion 62 of the motor housing 6 has been described. Only one of the meat stealing part 62b and the second meat stealing part 62c may be formed. In this case, the configuration in which only the first meat stealing portion 62b is formed is more preferable because the flange portion 62 is more easily deformed than the configuration in which only the second meat stealing portion 62c is formed.

  Further, at least one of the first and second meat stealing portions 72b and 72c is formed on the flange portion 72 of the gear housing 7, and the first and second meat stealing portions 62b are formed on the flange portion 62 of the motor housing 6. , 62c may be formed. In this case, the vibration of the electric motor 2 is more difficult to be transmitted to the gear housing 7.

  Furthermore, in the first and second embodiments, the case where the electric power steering device 10 applies a steering assist force to the column shaft 121 has been described. However, the present invention is not limited to this, and the pinion shaft 123 or the rack shaft 13 is applied. You may comprise so that steering assistance force may be provided. Even in this case, the same operations and effects as those of the first and second embodiments can be obtained.

DESCRIPTION OF SYMBOLS 1 ... Steering mechanism, 10 ... Electric power steering apparatus, 11 ... Steering wheel, 12 ... Steering shaft, 121 ... Column shaft, 121a ... Upper shaft, 121b ... Lower shaft, 122 ... Intermediate shaft, 123 ... Pinion shaft, 123a ... Pinion Teeth, 124, 125 ... Universal joint, 13 ... Rack shaft, 13a ... Rack teeth, 14 ... Torque sensor, 140 ... Torsion bar, 15 ... Rack housing, 16 ... Ball joint socket, 17 ... Tie rod, 18 ... Boot, 19 ... Steering wheel, 2 ... electric motor, 20 ... shaft, 21 ... rotor, 211 ... segment magnet, 22 ... stator, 220 ... stator core, 221 ... insulator, 222 ... coil, 231 ... first bearing, 232 ... second bearing, 24 ... resolver 241 ... Resolver rotor, 242 ... Resolver stator, 3 ... Gear mechanism, 31 ... Worm, 32 ... Worm wheel, 320 ... Base, 320a ... Fitting hole, 321 ... Tooth part, 4 ... Controller, 40 ... Substrate, 41 ... Electronic Parts, 42 ... Connector, 5 ... Steering column, 51 ... Outer tube, 52 ... Inner tube, 53 ... Bracket, 54 ... Operating lever, 6 ... Motor housing, 60 ... Base housing, 600 ... Cover housing, 601,602 ... Bolt , 61, 71 ... cylindrical part, 61a, 71a ... outer peripheral surface, 62, 72 ... flange part, 621 ... thick part, 621a, 621b ... end face, 622 ... thin part, 622a, 622b ... plane, 62a, 72a ... Hole part, 62b, 72b ... 1st meat stealing part, 62c, 72c ... 2nd meat stealing part, 63 ... Bottom part, 6 a ... recess, 7 ... gear housing, 70 ... worm housing, 700 ... sensor housing, 701 ... bolt, 70a, 70b ... accommodation space, 70A ... first accommodation portion, 70B ... second accommodation portion, 70c ... communication hole, 711 ... small diameter cylindrical part, 712 ... tapered part, 713 ... large diameter cylindrical part, 721 ... thick part, 721a, 721b ... end face, 722 ... thin part, 722a, 722b ... plane, 73 ... bottom part, 74 ... cylindrical part, 75 ... Flange part, 75a ... Screw hole, 76 ... Bottom part, 76a ... Insertion hole

Claims (4)

An electric motor, a gear mechanism that transmits the rotational force of the electric motor to a shaft that constitutes a steering mechanism as a steering assist force, a first housing that houses the electric motor, and a second housing that houses the gear mechanism Prepared,
Each of the first housing and the second housing has a cylindrical portion and a flange portion protruding from the outer peripheral surface of the cylindrical portion, the cylindrical portions are abutted with each other, and the flange portions are bolts Concluded by
Between the flange portions, the peripheral portions of the hole portion through which the bolt is inserted or screwed are abutted,
Wherein at least one of the flange portion of the first housing and the second housing, between the hole and the front Symbol cylindrical portion, an electric power thinned section transverse to said flange portion is formed Steering device. The cylindrical portion of the first housing and the cylindrical portion of the second housing have different outer diameters,
The meat stealing portion is formed on the flange portion provided on the outer peripheral surface of the cylindrical portion having a smaller outer diameter among the cylindrical portions,
The electric power steering apparatus according to claim 1. The hole portion of the flange portion of the first housing is formed as an insertion hole through which the bolt is inserted,
The hole portion of the flange portion of the second housing is formed as a screw hole into which a male screw portion of the bolt is screwed,
The meat stealing portion is formed in the flange portion of the second housing,
The electric power steering apparatus according to claim 1 or 2. The thickness of the flange portion of the portion where the meat stealing portion is formed is less than or equal to half the thickness of the peripheral portion of the hole portion,
The electric power steering apparatus according to any one of claims 1 to 3.

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