JP4309222B2 - Motor and power steering device - Google Patents

Description

  The present invention relates to a motor, and more particularly to a structure of a motor that is required to suppress propagation of vibration that occurs, for example, like an electric power steering device.

  2. Description of the Related Art Conventionally, there is an electric power steering device in which a motor is used as an auxiliary force for an operation force of a vehicle steering. In this electric power steering device, a motor (motor housing) is fixed to a motor mounting surface provided on a column of the vehicle.

  By the way, since a motor rotates, generation | occurrence | production of a vibration cannot be avoided. For this reason, when used as an auxiliary force of a power steering apparatus, it is required to prevent the vibration from being transmitted to the steering wheel, that is, to suppress the vibration propagation from the motor to the mounting surface.

For example, in Patent Document 1, there is a possibility that an elastic body is interposed between the electric motor and the housing of the speed reduction mechanism, and vibration generated in the case of the electric motor or the like is amplified by the housing of the speed reduction mechanism to generate a large noise. A structure for reducing the above is disclosed. In Patent Document 2, a motor bolt is fastened with a mounting bolt with a sheet made of a viscoelastic material interposed between the flange surface of the motor yoke and the mounting surface of the bracket facing the motor yoke. A structure for reducing vibration transmission from the motor yoke to the bracket is disclosed.
JP-A-11-198829 JP 2001-251807 A

  However, in the structure of Patent Document 1, there is a problem that the float member needs to hold the weight of the entire motor, and the float member becomes a large object. In the structure of Patent Document 2, the motor yoke is floated in the axial direction, but in the radial direction, since the metal contacts with the motor housing, vibrations propagate and there is a problem that the vibration suppressing effect is small.

  The present invention has been made in view of such circumstances, and an object of the present invention is a small motor that can float in the axial direction and the radial direction to suppress propagation of vibration, and a power steering device including the motor. Is to provide.

In order to solve the above-described problem, the invention according to claim 1 is a motor yoke having a substantially cylindrical shape and having a flange extending radially outward at the opening, and closing the opening, An end frame having an opposing fixing portion, an annular wall portion facing an inner peripheral surface of the motor yoke, a fastening member for fastening the motor yoke and the end frame, the flange, the fixing portion, and the An elastic member that elastically supports the inner peripheral surface and the annular wall portion so as to be separated from each other. The motor yoke holds a magnet on the inner side thereof, and the opening on the inner side of the opening end of the motor yoke. An expansion portion formed to expand toward the direction is formed, and the elastic member is opposed to an inner surface of the expansion portion and an inner peripheral surface of the motor yoke in the annular wall portion. It is sandwiched between the peripheral surface and the surface of the fixed portion and compressed, and the elastic member separates the inner peripheral surface of the motor yoke and the outer peripheral surface of the annular wall portion, and the distance between the magnet and the magnet Was set smaller than the distance to the rotor held inside .

According to a second aspect of the invention, in the motor according to claim 1, wherein the expanding portion is for expanding in a tapered shape toward the opening direction.

According to a third aspect of the present invention, in the motor according to the first or second aspect , the elastic member has a radial compression allowance at the opening end in the opening direction of the opening, and the anti-opening direction. It is formed so that the radial compression allowance increases toward the center.

According to a fourth aspect of the present invention, in the motor according to the first or second aspect, the elastic member is an O-ring.
According to a fifth aspect of the present invention, in the motor according to any one of the first to third aspects, the elastic member includes a first elastic portion interposed between the fixing portion and the flange. And a second elastic portion interposed between the annular wall portion and the inner peripheral surface of the motor yoke.

According to a sixth aspect of the present invention, in the motor according to the fifth aspect , the first elastic portion is formed in a flat plate shape, and the second elastic portion is arranged in an axial direction from an inner end portion of the first elastic portion. It is formed to extend in a cylindrical shape along.

The invention according to claim 7 is the motor according to claim 5 , wherein the first elastic part is a rubber packing sandwiched between the fixing part and the flange, and the second elastic part is the annular wall part. It is an O-ring accommodated in the groove | channel formed in the outer peripheral surface along the circumferential direction.

An eighth aspect of the invention is a power steering system comprising the motor according to any one of the first to seventh aspects, wherein the motor assists the steering force of the steering wheel. Device.

(Function)
According to the first aspect of the invention, since the elastic member supports only the motor yoke in a floating manner, the elastic member can be made small.

  In addition, since the motor yoke that is formed in a substantially cylindrical shape and easily vibrates is separated from the end frame in the axial direction and the radial direction, metal contact with the end frame is prevented, and a large vibration suppressing effect is obtained.

In addition , by setting an elastic member in the expanded portion that is formed to expand in the opening direction, the elastic member is compressed in the radial direction and the axial direction, and the motor yoke is floatingly supported in both directions.
Further, the elastic member is compressed between the inner side surface of the expanding portion and the outer peripheral surface of the annular wall portion, and the motor yoke is floatingly supported in the radial direction. Further, the elastic member is compressed between the inner surface of the expanding portion and the surface of the fixed portion, and the motor yoke is floatingly supported in the axial direction.

According to invention of Claim 2 , formation of the expansion part is easy by forming an expansion part in a taper shape. In addition, by forming the widened portion in a tapered shape, the widened portion can be formed with high accuracy, and the compression allowance of the elastic member compressed thereby can be grasped.

According to the third aspect of the present invention, there is no escape place of the elastic member due to compression, and at the same time, the compression margin in the radial direction of the elastic member is large at the position where the end frame in the opposite opening direction and the motor yoke are close to each other. It is possible to reliably perform the floating in the radial direction. In addition, since the compression margin at the end of the elastic member on the side opposite to the opening is small at the end of the opening, it is possible to easily mount the motor yoke sandwiching the elastic member.

According to the fourth aspect of the present invention, the elastic member made of an O-ring is easy to mount, and an increase in cost can be suppressed as compared with a general material.
According to the invention described in claim 5 , the first elastic portion is compressed between the flange of the motor yoke and the fixed portion of the end frame, and the motor yoke is floatingly supported in the axial direction. The second elastic portion is compressed between the inner peripheral surface of the motor yoke and the outer peripheral surface of the annular wall portion, and the motor yoke is floatingly supported in the radial direction.

According to the sixth aspect of the present invention, the first elastic portion formed in the flat plate ring shape is compressed between the housing of the motor yoke and the fixed portion of the end frame, and the motor yoke is floatingly supported in the axial direction. The second elastic portion formed in a cylindrical shape is compressed between the inner peripheral surface of the motor yoke and the outer peripheral surface of the annular wall portion, and the motor yoke is floatingly supported in the radial direction. Furthermore, since the first elastic part and the second elastic part are integrally formed, mounting is easy.

According to the seventh aspect of the present invention, since the elastic member is separated for the axial direction and the radial direction, the elastic member is reliably floating-supported in both directions.
According to the eighth aspect of the present invention, a small-sized electric power steering apparatus with a small vibration in the steering wheel can be obtained.

  According to the present invention, it is possible to provide a small motor that floats in the axial direction and the radial direction to suppress propagation of vibration, and a power steering device including the motor.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.
FIG. 4 is a partial perspective view of the electric power steering apparatus.

  In the power steering apparatus 1, forward / reverse rotation of a steering wheel 2 steered by a driver is transmitted to an output shaft 4 via a steering column 3, and forward / reverse rotation of the output shaft 4 is transmitted via a rack and pinion type steering apparatus. Are transmitted to steered wheels (both not shown).

  An electric power steering device motor 5 is attached to the steering column 3. The motor 5 is driven based on the steering force and rotation direction of the steering wheel 2, and the rotation force of the motor 5 is applied to the steering force of the steering wheel 2 by a gear (not shown) provided on the steering column 3, and the resultant force Thus, the steered wheels are steered through the output shaft 4 and the rack and pinion type steering device.

  As shown in FIG. 1, the motor 5 includes a motor housing 11 and a rotor (rotor) 12 that is rotatably held in the motor housing 11. The motor housing 11 includes a motor yoke 13 formed in a substantially bottomed cylindrical shape, and an end frame 14 that closes the opening of the motor yoke 13.

  A magnet holder 15 is fitted into the motor yoke 13, and a plurality of magnets 16 are held in the magnet holder 15. The rotor 12 is rotatably supported inside the magnets 16. That is, the rotor 12 is provided with a rotating shaft 17, and both ends of the rotating shaft 17 are rotatably supported via bearings 18 and 19 provided on the motor yoke 13 and the end frame 14, respectively.

  A commutator (commutator) 20 is provided on the rotary shaft 17 so as to be integrally rotatable. A brush device 21 is disposed on the end frame 14, and a brush 22 held by the brush device 21 is in sliding contact with the commutator 20.

  The end frame 14 includes a housing portion 23 having substantially the same outer diameter as that of the motor yoke 13, and a first fixing portion 24a and a second fixing portion 24b (FIG. 2) that are formed so as to protrude radially outward from the housing portion 23. Reference). Further, the end frame 14 is provided with a substantially cylindrical annular wall portion 24 c extending from the housing portion 23 along the axial direction of the motor 5.

  The annular wall portion 24 c is formed so that its outer diameter is smaller than the inner diameter of the motor yoke 13. Therefore, the annular wall portion 24 c is inserted into the motor yoke 13 when the motor yoke 13 is attached to the end frame 14.

  A screw hole 25 is formed in the first fixing portion 24a along the axial direction of the motor 5, and a mounting hole 26 penetrating the second fixing portion 24b along the axial direction is similarly formed in the second fixing portion 24b. Is formed.

  A recess 23 a is formed in the storage portion 23 from the end frame 14 side, and the brush device 21 is stored in the recess 23 a. The brush device 21 is floatingly supported on the end frame 14 with screws 29 through a floating rubber 27 and a collar 28 as elastic members.

  The tip of the rotating shaft 17 protrudes from the end frame 14, and a joint 30 is press-fitted at that portion, and the rotating shaft 17 is connected to a gear provided on the steering column 3 via the joint 30.

The fixing between the motor yoke 13 and the end frame 14 will be described.
The motor yoke 13 is formed with a flange 31 extending radially outward at the opening thereof. The inner surface of the opening portion of the motor yoke 13 is widened in the opening direction to form an expanding portion 32. The expanding portion 32 is formed to expand toward the opening direction. The expanding portion 32 is formed by, for example, a press.

  As shown in FIG. 3, the flange 31 is formed such that an outer end at a predetermined position in the circumferential direction protrudes outward in the radial direction, and a plurality of fixing portions 33 are formed by the protruding portion and the annular portion. The fixing portion 33 is formed at a position facing the first fixing portion 24 a of the end frame 14. Each fixing portion 33 is formed with an attachment hole 34 that passes through each fixing portion 33 in the axial direction of the motor 5. Then, a screw 35 as a fastening member inserted through the mounting hole 34 is screwed into the screw hole 25 of the first fixing portion 24 a, and the motor yoke 13 is attached to the end frame 14.

  A packing 41 as an elastic member is interposed between the motor yoke 13 and the end frame 14 over the entire circumference. The packing 41 has an L-shaped cross section and is formed in a thin annular shape, and extends in a cylindrical shape along the axial direction of the motor 5 from the inner end of the first elastic portion 42. It is comprised from the 2nd elastic part 43 formed out.

  The first elastic portion 42 is interposed between the surface outside the annular wall portion 24 c in the motor yoke 13 and the flange 31 of the end frame 14. The second elastic portion 43 is accommodated in a space surrounded by the outer surface of the annular wall portion 24c, the surface of the expanding portion 32, and the outer peripheral surface of the annular wall portion 24c, and is sandwiched between the surfaces. Yes. The opening end side inner diameter of the expanding portion 32 is formed larger than the outer diameter of the second elastic portion 43.

The motor yoke 13 is floatingly supported on the end frame 14 by screws 35 through a grommet 45 and a collar 46 as elastic members.
The collar 46 includes a cylindrical portion through which the screw 35 is inserted and a flange portion formed in a substantially rectangular shape as shown in FIG.

  Similar to the collar 46, the grommet 45 includes a cylindrical portion that is formed in a cylindrical shape and through which the collar 46 is inserted, and a flange portion that is formed in a substantially rectangular shape. The outer diameter of the cylindrical portion is formed substantially the same as the inner diameter of the mounting hole 34 formed in the fixed portion 33 of the motor yoke 13, and the inner diameter is formed approximately the same as the outer diameter of the cylindrical portion of the collar 46. The cylindrical portion has a length set so as to compress the grommet 45 and the first elastic portion 42 of the packing 41 in the axial direction of the motor 5.

  Accordingly, when the screw 35 is screwed into the screw hole 25 of the first fixing portion 24a so that the collar 46 contacts the first fixing portion 24a, the first elastic portion 42 of the packing 41 and the cylindrical portion of the grommet 45 are compressed, The motor yoke 13 is floatingly supported by the first elastic portion 42 of the packing 41 and the cylindrical portion and flange portion of the grommet 45.

  At this time, the second elastic portion 43 of the packing 41 is compressed by the first fixing portion 24 a and the annular wall portion 24 c of the end frame 14 and the expanding portion 32 of the motor yoke 13. And since the expansion part 32 is expanded toward the opening direction, as for the 2nd elastic part 43, the front-end | tip which contacts the expansion part 32 is compressed, and the annular wall part 24c is the radial inside of the motor 5 To receive power. By this force, the annular wall portion 24c of the end frame 14 is curved inward in the radial direction. Accordingly, the motor yoke 13 is floatingly supported by the second elastic portion 43 of the packing 41 in the radial direction of the motor 5. Further, the annular wall portion 24c of the end frame 14 is curved inward by the force generated by the attachment, and the annular wall portion 24c is separated from the inner peripheral surface of the motor yoke 13 and reliably floats in the radial direction.

  Further, as shown in FIG. 1, the distance L1 between the inner peripheral surface of the motor yoke 13 and the outer peripheral surface of the annular wall portion 24c of the end frame 14 is set smaller than the distance L2 between the magnet 16 and the rotor 12. ing. Therefore, even if the shaft center of the motor yoke 13 and the shaft center of the end frame 14 are deviated, the inner peripheral surface of the motor yoke and the annular wall portion 24c are engaged first, so that the rotor 12 and the magnet 16 interfere with each other. do not do.

As described above, according to this embodiment, the following effects can be obtained.
(1) The motor 5 includes a packing 41 as an elastic member. The packing 41 is formed between the flange 31 formed at the opening end of the motor yoke 13 formed in a substantially cylindrical shape and the first fixing portion 24a of the end frame 14, and on the inner peripheral surface of the motor yoke 13 and the end frame 14. It is interposed between the formed annular wall portions 24c and elastically supports them so as to separate them.

  Therefore, since the packing 41 supports only the motor yoke 13 in a floating manner, the packing 41 can be made small. Further, the packing 41 is formed in a substantially cylindrical shape, and the motor yoke 13 that easily vibrates is separated from the end frame 14 in the axial direction and the radial direction, so that metal contact between the end frame 14 and the motor yoke 13 is prevented. A large vibration suppressing effect can be obtained.

  (2) At the opening end of the motor yoke 13, an expanding portion 32 is formed so as to expand toward the opening direction, and the second elastic portion 43 of the packing 41 is formed on the inner surface of the expanding portion 32. Compressed. Accordingly, since the second elastic portion 43 of the packing 41 is compressed in the radial direction and the axial direction by the expanding portion 32, the motor yoke 13 can be reliably supported in a floating manner in both directions.

  (3) The first elastic portion 42 formed in a flat plate shape is compressed between the flange 31 of the motor yoke 13 and the fixing portion 24a of the end frame 14, so that the motor yoke 13 can be supported in a floating manner in the axial direction. The second elastic portion 43 formed in a cylindrical shape is compressed between the inner peripheral surface of the motor yoke 13 and the outer peripheral surface of the annular wall portion 24c, so that the motor yoke 13 can be floatingly supported in the radial direction. Furthermore, since the first elastic part 42 and the second elastic part 43 are integrally formed, mounting is easy.

(Second embodiment)
Hereinafter, a second embodiment of the present invention will be described with reference to the drawings.
In addition, the same code | symbol is attached | subjected about the same member as 1st embodiment, and the detailed description is abbreviate | omitted.

FIG. 5 is a longitudinal sectional view of the motor 50 for the electric power steering apparatus of the present embodiment, and FIG. 6 is a side view of the motor 50.
This motor 50 is attached to the steering column 3 of FIG. 4 in place of the motor 5 of the first embodiment.

  The motor 50 includes a motor housing 51 and a rotor (rotor) 12 that is rotatably held in the motor housing 51. The motor housing 51 includes a motor yoke 52 formed in a substantially bottomed cylindrical shape, and an end frame 14 that closes the opening of the motor yoke 52.

  As shown in FIG. 7, a U-shaped notch 54 is formed in the fixing portion 53 of the motor yoke 52 inward in the radial direction, and a collar 46 and a grommet 45 are provided in each notch 54. It is inserted. Each notch 54 is formed so that the centers of the respective collars 46 and grommets 45 fitted therein are equidistant from the shaft center of the motor 50.

  As shown in FIG. 5, the motor 50 is provided with an O-ring 55 as a ring-shaped elastic member. The O-ring 55 is accommodated in a space surrounded by a surface outside the annular wall portion 24c, a surface of the spread portion 32, and an outer peripheral surface of the annular wall portion 24c, and is sandwiched between the surfaces.

  The O-ring 55 is compressed by the first fixed portion 24 a and the annular wall portion 24 c of the end frame 14 and the expanded portion 32 of the motor yoke 52. And since the expansion part 32 is expanded toward the opening direction, as for the O ring 55, the front end side and the outer peripheral side are compressed by the expansion part 32, and toward the radial inside and axial direction of the motor 50. Receive power. With this force, the motor yoke 52 is elastically supported in the axial direction with respect to the end frame 14 and elastically supported in the radial direction with respect to the annular wall portion 24 c of the end frame 14. That is, the motor yoke 52 is floatingly supported by the O-ring 55 in the radial direction and the axial direction of the motor 50.

As described above, according to this embodiment, the following effects can be obtained.
(1) The O-ring 55 is easy to mount, and is easier to obtain than general materials (for example, packing), and can suppress an increase in cost.

  (2) Since the O-ring 55 is disposed between the expanded portion 32, the end frame 14, and the annular wall portion 24c, and the expanded portion 32 is formed inside the opening end of the motor yoke 13, the motor yoke 13 The opening ends of the first and second openings are spaced apart from the end frame 14 in the axial direction, and are spaced apart from the annular wall portion 24c outward in the radial direction. For this reason, the center of the annular wall 24c and the motor yoke 13 coincide, that is, the center of the end frame 14 and the center of the motor yoke 13 can be easily matched.

In addition, you may change embodiment of this invention as follows.
○ Each of the above embodiments may be modified as appropriate.
For example, the motor 60 shown in FIG. The motor 60 includes an annular plate-shaped packing 61 that functions as a first elastic portion and an O-ring 62 that functions as a second elastic member as elastic members. The packing 61 is interposed between the flange 64 of the motor yoke 63 and the end frame 14, and supports the motor yoke 52 in a floating manner in the axial direction of the motor 60. The O-ring 62 is accommodated in a groove 24e formed in the annular wall portion 24d of the end frame 14 so as to extend in the circumferential direction, and is interposed between the annular wall portion 24c and the inner peripheral surface of the motor yoke 63. The motor yoke 52 is supported in a floating manner in the radial direction of the motor 60. In this case, since the elastic member is separated for the axial direction and the radial direction, the elastic member is surely supported in a floating manner in both directions. Moreover, since each elastic part (packing 61 and O-ring 62) is simple in shape, the cost can be kept low.

  Further, it is embodied in a motor 70 shown in FIG. The motor 70 includes a motor yoke 71, and an inner surface of the opening portion of the motor yoke 71 is widened in the opening direction to form an expanding portion 72 in a tapered shape. The opening end side inner diameter of the expanding portion 72 is formed to be substantially equal to the outer diameter of the second elastic portion 43. Therefore, the taper surface of the expanded portion 72 is in contact with the outer peripheral surface of the second elastic portion 43. For this reason, the second elastic portion 43 is compressed in the entire region in the axial direction from the proximal end to the distal end, and the compression margin increases toward the distal end. For this reason, since the second elastic portion 43 has no escape space due to compression, the motor yoke 52 can be more reliably floating-supported in the radial direction. Further, due to the widened portion 72 formed in a tapered shape, the second elastic portion 43 has a small compression allowance at the non-opening end side portion, that is, the base end portion. That is, since the motor yoke 71 has a small compression allowance of the second elastic portion 43 at the opening end portion of the expanding portion 72, the force applied in the axial direction of the motor 70 when the motor yoke 71 is mounted on the end frame 14. The motor yoke 71 may be easily mounted with the second elastic portion 43 interposed therebetween.

  In the first embodiment, the distance from the axial center of the screw hole 25 formed in the end frame 14 and the distance from the axial center of the mounting hole 34 formed in the motor yoke 13 are different. For example, the distance from the axis center to the center of the screw hole 25 is made smaller than the distance from the axis center to the mounting hole 34. With this configuration, the axial center side of the grommet 45 through which each screw 35 is inserted is compressed by the screw 35 that attaches the motor yoke 13 to the end frame 14, so that the center of the end frame 14 and the center of the motor yoke 13 Can be easily matched.

  The motors of the above embodiments may be applied to devices other than the electric power steering device.

The longitudinal cross-sectional view of the motor of 1st embodiment. The side view of a motor. The side view of a motor yoke. The partial perspective view of an electric power steering device. The longitudinal cross-sectional view of the motor of 2nd embodiment. The side view of a motor. The side view of a motor yoke. (A) and (b) are partial sectional views of another motor.

Explanation of symbols

  2 ... Steering wheel, 5, 50, 60, 70 ... Motor, 14 ... End frame, 13, 52, 63, 71 ... Motor yoke, 24a, 33, 53 ... Fixed part, 24c, 24d ... Annular wall part, 24e ... Groove, 31, 64 ... flange, 32, 72 ... expanded portion, 41, 61 ... packing, 42 ... first elastic portion, 43 ... second elastic portion, 55, 62 ... O-ring.

Claims (8)

A motor yoke having a flange formed in a substantially cylindrical shape and extending radially outward in the opening;
An end frame that closes the opening, has a fixed portion facing the flange, and an annular wall portion facing the inner peripheral surface of the motor yoke;
A fastening member for fastening the motor yoke and the end frame;
An elastic member that elastically supports the flange and the fixed portion, and the inner peripheral surface and the annular wall portion so as to be separated from each other ;
In the motor yoke, a magnet is held on the inner side, and an opening portion is formed inside the opening end of the motor yoke so as to expand toward the opening direction.
The elastic member is compressed by being sandwiched between an inner surface of the expanding portion, an outer peripheral surface of the annular wall portion facing the inner peripheral surface of the motor yoke, and a surface of the fixing portion. The inner peripheral surface of the motor yoke and the outer peripheral surface of the annular wall portion are separated from each other, and the separation distance is set smaller than the distance between the magnet and the rotor held inside the magnet. motor. The motor according to claim 1 , wherein the expanding portion expands in a tapered shape toward the opening direction . In the opening direction of the opening, the elastic member has a radial compression margin at the end of the opening, and is formed so that a radial compression margin increases toward the non-opening direction. the motor according to claim 1 or 2,. The motor according to claim 1 or 2, wherein the elastic member is an O-ring. The elastic member includes: a first elastic portion interposed between the fixed portion and the flange; and a second elastic portion interposed between the annular wall portion and the inner peripheral surface of the motor yoke. motor according to any one of claims 1-3, characterized in that it is configured. The first elastic part is formed in a flat plate shape,
The motor according to claim 5, wherein the second elastic portion is formed to extend in a cylindrical shape along an axial direction from an inner end portion of the first elastic portion . The first elastic part is a rubber packing sandwiched between the fixed part and the flange,
6. The motor according to claim 5, wherein the second elastic portion is an O-ring accommodated in a groove formed along the circumferential direction on the outer peripheral surface of the annular wall portion . A power steering apparatus comprising the motor according to any one of claims 1 to 7, wherein the motor assists a steering force of a steering wheel.

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