JP2014180103A - Motor and electric power steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor which can stably maintain fitting quality of a fitting plate for a case body and allows the quality to be confirmed only by its appearance.SOLUTION: In a motor 30 where a motor case 50 has a cup-shaped, bottomed case body 51 and a fitting plate 70 which is fixed to a bottom part side of the case body 51 and protrudes in an outer diameter direction of the case body 51, the fitting plate 70 comprises: a fitting part 74 which protrudes in the outer diameter direction of the case body 51 and is fitted to a housing 92 via a bolt 93; and a fixing part 73 which is placed at a position corresponding to a bottom part 56 and extends in a diameter direction of the bottom part 56. A recessed part 56a for housing the fixing part 73 in the bottom part 56 is formed in the diameter direction. The recessed part 56a opens to one side in an axial direction of the case body 51, and a caulking part which protrudes in a circumferential direction is formed by plastic deformation on the opening side of the recessed part 56a of the bottom part.

Description

  The present invention relates to a motor and an electric power steering apparatus.

  As a conventional power steering device for a vehicle, there is one that uses an electric motor 130 as shown in FIG. 5 (Patent Document 1) in order to power assist a driver's steering wheel operation. The electric motor 130 is attached to the gear housing 192 via attachment bolts 193.

  The electric motor 130 is fitted and fixed to the motor case 150, the stator 131 fitted and fixed to the inner periphery of the motor case 150, the rotor 135 disposed on the inner periphery of the stator 131, and the inner periphery of the rotor 135. An output shaft 138 and rolling bearings 180 and 181 that are disposed in the motor case 150 and rotatably support the output shaft 138 are formed.

  The motor case 150 has a cup-shaped cylindrical case body 151, a mounting plate 170 fitted to the case body 151 and fixed by spot welding, and a lid plate 160 fitted to the opening side of the case body 151. It is made up of. An electronic control unit 190 is attached to the lid plate 160.

  The case main body 151 includes a large-diameter cylindrical portion 153, a medium-diameter cylindrical portion 154 having a smaller diameter than the large-diameter cylindrical portion 153, and a small-diameter cylindrical portion 155 having a smaller diameter than the medium-diameter cylindrical portion 154. At the bottom of the case main body 151 on the gear housing 192 side, a cylindrical fitting portion 159, a first bottom portion 158 extending in the radial direction of the output shaft 138, and an inclined portion 157 extending in a taper shape in the radial direction of the output shaft 138. And the 2nd bottom part 156 extended in the radial direction of the output shaft 138 is formed in order in the outer diameter direction.

  The mounting plate 170 includes a cylindrical cylindrical portion 172 fitted into the small diameter cylindrical portion 155 and a mounting portion 174 extending in the outer diameter direction from one end of the cylindrical portion 172 in the axial direction.

  The cylindrical portion 172 is fitted to the small diameter cylindrical portion 155, one electrode of spot welding is disposed on the inner peripheral side of the small diameter cylindrical portion 155, the other electrode of spot welding is disposed on the outer periphery of the cylindrical portion 172, and a pair of By bringing the electrodes closer to each other, spot welding is performed between the small diameter cylindrical portion 155 and the cylindrical portion 172, and by repeatedly performing spot welding while rotating the small diameter cylindrical portion 155 and the cylindrical portion 172 in the circumferential direction, A total of four spot welds are applied.

JP 2012-90496 A

  In order to place one electrode for spot welding in a narrow space between the small diameter cylindrical portion 155 and the inclined portion 157, the electrode must be miniaturized, the pressing force during welding becomes unstable, and the welding quality is maintained. Difficult to do. In addition, it is necessary to check the welding quality not only with the appearance but also with X-rays, and the cost is high to ensure the quality.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a motor and an electric power that can stably maintain the mounting quality of the mounting plate with respect to the case body and can check the quality only by the appearance. A steering device is provided.

A motor for solving the above problems includes a motor case attached to a housing via a coupling mechanism, a stator attached to the inner periphery of the motor case, an output shaft rotatably supported by the motor case, A rotor integrally formed with the output shaft and rotating with respect to the stator;
In the motor, the motor case has a cup-shaped case body having a bottom, and a mounting plate that is fixed to the bottom of the case body and protrudes in the outer diameter direction of the case body.
The mounting plate protrudes in the outer diameter direction of the case main body, is attached to the housing via the coupling mechanism, and is disposed at a position corresponding to the bottom portion and extends in the radial direction of the bottom portion. Consists of
Forming a concave portion for accommodating the fixing portion in the bottom portion in the radial direction, the concave portion opening on one side in the axial direction of the case body;
A caulking portion protruding in a circumferential direction by plastic deformation is formed on the opening side of the concave portion of the bottom portion.

  According to the above configuration, since caulking is performed on the outside of the case body, the attachment quality of the attachment plate to the case body can be stably maintained. Moreover, since the amount of protrusion of the caulking portion in the circumferential direction and the thickness of the caulking portion can be confirmed by appearance, the attachment quality of the mounting plate to the case body can be confirmed only by appearance.

  In the motor for solving the above problems, the motor case has a cylindrical first cylindrical portion, and the mounting plate is fitted to the outer periphery of the first cylindrical portion of the motor case. It has a 2nd cylindrical part, The said 2nd cylindrical part is arrange | positioned between the said attaching part and the said fixing | fixed part in radial direction, It is characterized by the above-mentioned.

  According to the above configuration, the mounting plate is less likely to come off in the radial direction with respect to the motor case, so that the mounting quality of the mounting plate to the case body can be maintained more stably.

  In the motor for solving the above problems, the mounting plate is formed by cutting out and bending a sheet metal to form the mounting portion, the second cylindrical portion, and the fixing portion, respectively. The attachment portion or the fixing portion is formed by bending a part thereof.

  According to the said structure, a mounting plate can be manufactured at low cost.

  An electric power steering apparatus for solving the above problems is a gear housing that rotatably accommodates a worm wheel and a worm gear. The gear housing, the worm wheel, the worm gear, and any one of claims 1 to 3 The motor according to claim 1 is provided.

  According to the said structure, the attachment quality of the attachment plate with respect to a case main body can be maintained stably, and the electric power steering apparatus which can confirm quality only by an external appearance can be provided.

  ADVANTAGE OF THE INVENTION According to this invention, the attachment quality of the attachment plate with respect to a case main body can be maintained stably, and the motor and electric power steering apparatus which can confirm quality only by an external appearance can be provided.

1 is a schematic configuration diagram of an electric power steering apparatus according to an embodiment of the present invention. It is sectional drawing which shows the attachment structure of the electric motor concerning one Embodiment of this invention. It is the sectional view on the AA line of FIG. 2 concerning one Embodiment of this invention. It is the BB sectional drawing of FIG. 2 concerning one Embodiment of this invention. It is sectional drawing which shows the attachment structure of the conventional motor.

  An embodiment as an example of the present invention will be described with reference to FIGS. 1 to 5. 1 is a schematic configuration diagram of an electric power steering device, FIG. 2 is a cross-sectional view showing a mounting structure of an electric motor, FIG. 3 is a cross-sectional view taken along line AA in FIG. 2, and FIG. It is B line sectional drawing.

  As shown in FIG. 1, the electric power steering apparatus 10 includes a column mechanism 20 whose one end is rotationally connected to a handle 21, an intermediate shaft 39 that is rotationally connected to the other end of the column mechanism 20, and an intermediate shaft 39. A rack-and-pinion mechanism 40 rotatably connected to the end. The rack and pinion mechanism 40 is connected to the snake ring 47 via knuckle arms 46 provided at both left and right ends. The electric power steering apparatus 10 has a function of transmitting the operation of the handle 21 to the knuckle arm 46 through the column mechanism 20, the intermediate shaft 39, and the rack and pinion mechanism 40 and changing the direction of the snake ring 47. In addition, the electric motor 30 provided in the column mechanism 20 has a power assist function.

  As shown in FIGS. 1 and 2, the column mechanism 20 includes a steering shaft 22 whose one end is rotationally connected to the handle 21, an unillustrated intermediate shaft rotationally connected to the other end of the steering shaft 22, and an intermediate shaft 39. An output shaft 23 that is rotationally connected to one end of the motor, a torsion bar 26 that rotationally connects the intermediate shaft and the output shaft 23, an electric motor 30 that assists power according to the torsion of the torsion bar 26, and an output shaft 38 of the electric motor 30. The worm gear 25 is rotatably connected to the worm gear 25, the worm wheel 24 meshes with the worm gear 25, and a gear housing 92 that rotatably supports the intermediate shaft and the output shaft 23. The worm wheel 24 is fitted and fixed to the outer periphery of the output shaft 38 and rotates integrally with the output shaft 38. The torsion bar 26 has a function of increasing the twist angle when the handle torque is increased. The worm gear 25 and the worm wheel 24 have a function of reducing the rotation of the output shaft 38 of the electric motor 30.

  As shown in FIG. 1, the rack and pinion mechanism 40 includes a pinion shaft 41 that is rotationally connected to the other end of the intermediate shaft 39, a rack shaft 43 that moves in a direction intersecting the rotation axis of the pinion shaft 41, A tie rod 45 connected to both ends of the shaft 43 and a rack housing (not shown) that supports the pinion shaft 41 rotatably and supports the rack shaft 43 movably in the axial direction. Pinion teeth 42 are formed on the pinion shaft 41, rack teeth 44 are formed on the rack shaft 43, and the pinion teeth 42 and the rack teeth 44 mesh with each other. Thus, the rotational motion of the pinion shaft 41 is converted into the axial motion of the rack shaft 43.

  As shown in FIGS. 2 to 4, the electric motor 30 includes a motor case 50, a stator 31 fitted and fixed to the inner periphery of the motor case 50, a rotor 35 disposed on the inner periphery of the stator 31, and the rotor 35. The output shaft 38 is fitted and fixed to the inner periphery of the motor shaft 50, and the rolling bearings 80 and 81 are disposed in the motor case 50 and rotatably support the output shaft 38.

  As shown in FIG. 2, the stator 31 is wound around a cylindrical cylindrical portion, a plurality of teeth 32 extending from the cylindrical portion toward the inner diameter side, an insulator 33 provided around each tooth 32, and the insulator 33. And a coil 34. The cylindrical part and the teeth 32 are made of iron integrally formed with each other, and the insulator 33 is made of resin.

  The rotor 35 includes a rotor core 37 that is fitted and fixed to the output shaft 38, and a plurality of magnets 36 that are arranged on the outer periphery of the rotor core 37 in the circumferential direction. The rotor core 37 is made of iron, and the magnet 36 is a magnet. When a current is applied to the coil 34, magnetic lines around the teeth 32 are generated, repelling the magnetic lines on the magnet 36 side, and the rotor 35 rotates.

  As shown in FIGS. 2 to 4, the motor case 50 is fitted into a cup-shaped cylindrical case body 51, a mounting plate 70 fixed to the bottom of the case body 51, and the opening side of the case body 51. And a cylindrical reinforcing member 66 fitted and fixed to the outer periphery of the case main body 51. The reinforcing member 66 is provided at a position corresponding to the stator 31 in the axial direction of the case body 51. An electronic control device 90 is attached to the lid plate 60. The case main body 51, the mounting plate 70, and the lid plate 60 are all made of iron, and are formed by cutting and bending with a press.

  The case body 51 includes a first attachment portion 52 extending in the outer diameter direction, a cylindrical large-diameter cylindrical portion 53, a medium-diameter cylindrical portion 54 having a smaller diameter than the large-diameter cylindrical portion 53, and a smaller-diameter than the medium-diameter cylindrical portion 54. Small-diameter cylindrical portions 55 are sequentially formed in the axial direction. At the bottom of the case body 51 on the gear housing 92 side, a cylindrical fitting portion 59, a first bottom portion 58 extending in the outer diameter direction, an inclined portion 57 extending in a taper shape in the outer diameter direction, and an outer diameter direction. An extending second bottom portion 56 is formed in order in the outer diameter direction.

  The stator 31 is fitted and fixed to the inner circumference of the medium diameter cylindrical portion 54, and the reinforcing member 66 is fitted and fixed to the outer circumference of the middle diameter cylindrical portion 54. A second cylindrical portion 72 described later is fitted to the outer periphery of the small diameter cylindrical portion 55. A rolling bearing 81 is fitted to the inner periphery of the fitting portion 59, an output shaft 38 is fitted to the inner periphery of the rolling bearing 81, and the output shaft 38 can rotate to the fitting portion 59 via the rolling bearing 81. It is supported by. A concave portion 56 a that accommodates a fixing portion 73 described later is formed in the second bottom portion 56 in the radial direction, and the concave portion 56 a is opened on one side in the axial direction of the case main body 51. A caulking portion 56b protruding in the circumferential direction by plastic deformation is formed on the opening side of the concave portion 56a of the second bottom portion 56.

  The mounting plate 70 includes a cylindrical second cylindrical portion 72 fitted to the small diameter cylindrical portion 55, a disk-shaped disk portion 71 extending in the outer diameter direction from one axial end of the second cylindrical portion 72, and a disk portion The second mounting portion 74 extends in the outer diameter direction from 71, and the fixing portion 73 extends in the inner diameter direction from the disk portion 71. In the radial direction of the mounting plate 70, the second cylindrical portion 72 is disposed between the disk portion 71 and the fixed portion 73. The second mounting portions 74 are formed at a total of two locations in the circumferential direction of the mounting plate 70, the fixing portions 73 are formed at a total of four locations, and the second mounting portions 74 are the same as the two locations of the fixing portions 73. Formed in phase. The second mounting portion 74 is fixed to the gear housing 92 via mounting bolts 93. The attachment plate 70 is formed by cutting out and bending an iron sheet metal to form a second attachment portion 74, a second cylindrical portion 72, a disc portion 71, and a fixing portion 73, and a part of the second cylindrical portion 72. Was fixed to form a fixing portion 73.

  The lid plate 60 includes a cylindrical third cylindrical portion 64, a first upper portion 63 extending in the outer diameter direction, a fourth cylindrical portion 62 having a cylindrical shape, and a second upper portion 61 extending in the outer diameter direction. A rolling bearing 80 is fitted to the inner periphery of the third cylindrical portion 64, an output shaft 38 is fitted to the inner periphery of the rolling bearing 80, and the output shaft 38 is connected to the third cylindrical portion 64 via the rolling bearing 80. It is rotatably supported. The second upper part 61 is attached to the first attachment part 52 via a fixing screw 91.

  The outer periphery of the pair of rolling bearings 82 and 83 is fitted into the gear housing 92, and the worm gear 25 is fitted to the inner circumference of the pair of rolling bearings 82 and 83. The worm gear 25 is disposed coaxially with the output shaft 38. A pressing member 86 is screwed into the gear housing 92 and one end of the pressing member 86 contacts the end surface of the rolling bearing 82, thereby preventing the rolling bearing 82 from coming off from the gear housing 92. On the outer periphery of the rolling bearing 83, a spring 87 having a ring shape and having a bulge in the outer diameter direction in a part in the circumferential direction is fitted, and the spring 87 is fitted in the gear housing 92. A resin-made cylindrical ring 88 is fitted into the gear housing 92, and a lid member 89 is fitted therein. The ring 88 and the lid member 89 can prevent the spring 87 from coming off from the gear housing 92, and the worm gear 25 is elastically supported in the radial direction by the spring 87.

  A first coupling member 84 made of resin is attached to one end of the output shaft 38, and a second coupling member 85 made of resin is attached to the other end of the worm gear 25. Teeth and grooves are alternately formed in the circumferential direction on the mutually facing surfaces of the first coupling member 84 and the second coupling member 85. When the teeth of the first coupling member 84 and the teeth of the second coupling member 85 are engaged with each other, the rotation of the output shaft 38 is transmitted to the worm gear 25 via the first coupling member 84 and the second coupling member 85. Reportedly.

  Next, the assembly of the electric motor 30 will be described based on the above-described configuration.

  A reinforcing member 66 is fitted and fixed to the outer periphery of the medium diameter cylindrical portion 54.

  The mounting plate 70 is fitted into the case body 51 in the axial direction from one end side of the case body 51 in the axial direction. That is, at the same time as the second cylindrical portion 72 is fitted to the outer periphery of the small diameter cylindrical portion 55, the fixing portion 73 is fitted into the concave portion 56a. The opening side of the concave portion 56a of the second bottom portion 56 is pressed in the axial direction from one end side in the axial direction of the case body 51 with a caulking tool. The opening side of the concave portion 56a of the second bottom portion 56 is plastically deformed to form a caulking portion 56b protruding in the circumferential direction. In this way, the mounting plate 70 is fixed to the case body 51.

  Since the caulking portion 56b is pressed in the axial direction from the outside of the case main body 51, the caulking work is easily performed and the caulking quality is stabilized. Since the amount of protrusion in the circumferential direction of the caulking portion 56b and the thickness of the caulking portion 56b can be determined from the appearance, the cost of quality inspection can be suppressed. By fitting the second cylindrical portion 72 to the outer periphery of the small diameter cylindrical portion 55, the inclination of the case body 51 with respect to the mounting plate 70 can be suppressed.

  The stator 31 is fitted and fixed to the inner periphery of the medium diameter cylindrical portion 54, the rotor 35 is fitted and fixed to the output shaft 38, and rolling bearings 80 and 81 are fitted to both ends of the output shaft 38. The output shaft 38, the rotor 35, and the rolling bearings 80 and 81 are inserted into the case body 51 and the stator 31 in the axial direction from the other end side in the axial direction of the case body 51. At the same time as the rolling bearing 81 is fitted to the inner circumference of the fitting portion 59, the rotor 35 is disposed on the inner circumference side of the stator 31.

  The lid plate 60 is attached to the case body 51 in the axial direction from the other end side of the case body 51 in the axial direction, and the fixing screw 91 is screwed to the second upper portion 61 via the first attachment portion 52. Thus, the rolling bearing 80 is fitted to the inner periphery of the third cylindrical portion 64, and the lid plate 60 is fixed to the case body 51. An electronic control unit 90 is attached to the lid plate 60.

  In a state where the pair of rolling bearings 82 and 83, the worm gear 25 and the worm wheel 24 are assembled to the gear housing 92, the second coupling member 85 is attached to the other end of the worm gear 25, and the first coupling shaft is connected to the first end of the output shaft 38. A coupling member 84 is attached. The electric motor 30 is brought closer to the gear housing 92 in the axial direction from the other axial end side of the worm gear 25, and the disk portion 71 and the second mounting portion 74 are brought into close contact with the gear housing 92. The mounting bolt 93 is screwed into the gear housing 92 via the second mounting portion 74, and the electric motor 30 is fixed to the gear housing 92.

  The present invention is not limited to these embodiments, and can of course be implemented in various modes without departing from the gist of the present invention.

  In the above embodiment, the second mounting portion 74, the second cylindrical portion 72, the disk portion 71, and the fixing portion 73 are formed on the mounting plate 70. As another embodiment, the second cylindrical portion 72 and the disk portion 71 may be omitted, and the mounting plate 70 including only the second mounting portion 74 and the fixing portion 73 may be formed. In this case, the mounting plate 70 can be prevented from coming off in the radial direction with respect to the case body 51 by the concave portions 56a and the fixing portions 73 formed in a total of four locations in the circumferential direction.

  In the above embodiment, the attachment plate 70 is attached to the gear housing 92 via the attachment bolt 93. As another embodiment, the attachment plate 70 may be attached to the gear housing 92 via a resin connection pin (coupling mechanism). For this purpose, a pin hole is formed in the gear housing 92, an enlarged hole having a larger diameter in the back thereof, and a step portion is formed between the pin hole and the enlarged hole. The connecting pin has a head with a large diameter and a shaft with a small diameter, and a slit is formed at the tip of the shaft, the tip of the shaft expands in the radial direction, and a step is formed at the tip of the shaft. A hook part is provided to be engaged with. In this way, when the shaft portion is inserted into the pin hole and the tip of the shaft portion reaches the expansion hole, the tip of the shaft portion expands in the outer diameter direction, and the flange portion engages with the stepped portion.

30: Electric motor (motor), 31: Stator, 35: Rotor, 50: Motor case, 51: Case body, 56: Second bottom (bottom), 56a: Recessed part, 56b: Caulking part, 70: Mounting plate, 73 : Fixing part, 74: Mounting part, 92: Gear housing (housing), 93: Mounting bolt (coupling mechanism)

Claims (4)

A motor case attached to the housing via a coupling mechanism; a stator attached to the inner periphery of the motor case; an output shaft rotatably supported by the motor case; and the output shaft, A rotor that rotates relative to the stator,
In the motor, the motor case has a cup-shaped case body having a bottom, and a mounting plate that is fixed to the bottom of the case body and protrudes in the outer diameter direction of the case body.
The mounting plate protrudes in the outer diameter direction of the case main body, is attached to the housing via the coupling mechanism, and is disposed at a position corresponding to the bottom portion and extends in the radial direction of the bottom portion. Consists of
Forming a concave portion for accommodating the fixing portion in the bottom portion in the radial direction, the concave portion opening on one side in the axial direction of the case body;
A motor characterized in that a caulking portion protruding in a circumferential direction by plastic deformation is formed on an opening side of the concave portion of the bottom portion. The motor case has a cylindrical first cylindrical part, and the mounting plate has a cylindrical second cylindrical part fitted to the outer periphery of the first cylindrical part of the motor case, The motor according to claim 1, wherein the two cylindrical portions are disposed between the attachment portion and the fixed portion in a radial direction. The mounting plate is formed by cutting out and bending a sheet metal to form the mounting portion, the second cylindrical portion, and the fixing portion, respectively, and bending the part of the second cylindrical portion to The motor according to claim 2, wherein a fixing portion is formed. The housing is a gear housing that rotatably accommodates a worm wheel and a worm gear, the gear housing, the worm wheel, the worm gear, and the motor according to any one of claims 1 to 3. An electric power steering apparatus.

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