JP6012154B2 - Brushless motor for electric power steering apparatus and manufacturing method thereof - Google Patents

Description

  The present invention relates to a brushless motor that includes a stator core and a rotor that rotates within the stator core, and that is particularly suitable for use as an in-vehicle drive source.

  Conventionally, an electric power steering device (EPS) is mounted on a vehicle such as an automobile, and the electric power steering device assists the steering of a steering wheel by a driver. The electric power steering device employs a brushless motor with excellent control performance as a drive source, which allows the driver to accurately control the brushless motor in the forward and reverse directions according to the steering angle of the steering wheel. On the other hand, an appropriate operational feeling is given. As a brushless motor employed as a drive source of such an electric power steering device, for example, a technique described in Patent Document 1 is known.

  The electric motor (brushless motor) described in Patent Document 1 includes an aluminum motor housing (motor case) formed in a cylindrical shape, and a stator (stator core) is fixed inside the motor housing. . A rotor (rotor) having an output shaft (rotating shaft) is rotatably provided inside the stator. The stator is wound with three-phase armature windings (coils) of U, V, and W via an insulator, and the drive current is alternately supplied to these three-phase armature windings to rotate the stator. The child (output shaft) rotates in the forward direction or the reverse direction.

  An aluminum cover (accommodating member) is attached and fixed to the rear end side of the motor housing via a large current substrate, and an insulating multilayer substrate (control device) is accommodated inside the cover. A semiconductor switching element, a conductive plate, and the like are mounted on the high current substrate, and an electronic component such as a semiconductor switching element, an electric field capacitor, and a shunt resistor, which are part of power circuit components, is mounted on the insulating multilayer substrate.

JP 2008-174097 A (FIGS. 1 and 2)

  However, according to the technique described in Patent Document 1 described above, each of the motor case and the housing member is made of aluminum. Therefore, after casting the motor case and the housing member, the inner peripheral surface of the motor case (the stator core) The fixing part), the abutting surfaces that are abutted against each other, and the like are ground, thereby requiring a dimensioning operation (secondary operation) to obtain a normal dimension. Therefore, not only the manufacturing process becomes complicated but also the manufacturing cost increases, and the motor case and the housing member must be made thick, and the volume of the motor increases.

  The object of the present invention is to reduce the manufacturing cost while simplifying the manufacturing process, and to further reduce the size and weight even if the housing member is connected to the housing member that houses the control device. It is to provide a brushless motor.

Brushless motor for an electric power steering apparatus of the present invention includes a stator core, an electric brushless motor for a power steering apparatus having a rotor which rotates within the stator core, made of steel sheet obtained by press molding, one axial An opening is provided on the side, a bottom wall is integrally provided on the other side in the axial direction, and a bottomed cylindrical motor case in which the stator core is fixed, and a distal end side of a rotating shaft fixed to the rotor A support member that rotatably supports and closes the opening on one side in the axial direction of the motor case, and a control that is provided on the bottom wall side on the other side in the axial direction of the motor case and controls driving of the rotor a housing member for housing the device, and the provided in the motor case, the first motor case side fixing portion fixed to the supporting member-side fixing portion provided on the support member Provided in the motor case, and a second motor case side fixing portion fixed to the housing member-side fixing portion provided on the housing member, said second motor case side securing portion, said motor case It is fixed to the outer peripheral surface near the housing member .

Brushless motor for an electric power steering apparatus of the present invention, the second motor case-side fixing portion is made of steel sheet obtained by press molding, a fixed portion fixed to the housing member-side fixing portion, wherein the motor case characterized in that it and a fixing portion which is welded to.
Brushless motor for an electric power steering apparatus of the present invention, the first motor case-side fixing portion is a flange portion provided on the outer periphery of the opening in one axial side of the motor casing, the flange portion It said support member and said Tei Rukoto attached.
Brushless motor for an electric power steering apparatus of the present invention, the support member is connected to the deceleration mechanism for decelerating the rotation of said rotary shaft, characterized in Tei Rukoto.

Brushless motor for an electric power steering apparatus of the present invention, a through-hole the base end side of said rotary shaft penetrates is provided in the front Symbol bottom wall, the base end side of said rotary shaft extending from the through hole, magnetic rotation sensor for detecting rotation of said rotary shaft, characterized that you have been placed.

Electric power brushless motor steering system of the present invention, wherein the housing member toward the motor case side stepped portion recessed radially inwardly to the motor case is provided, radially outside the motor case side of the said housing member recessed receiving member side step portion is provided, wherein Rukoto the motor case side step portion and said housing member side step portion in the opposing are not the state, and the housing member and the motor case is connected And

A method for manufacturing a brushless motor for an electric power steering apparatus according to the present invention is a method for manufacturing a brushless motor for an electric power steering apparatus that includes a stator core and a rotor that rotates within the stator core. A bottomed cylindrical motor case in which an opening is provided on one side in the axial direction, a bottom wall is integrally provided on the other side in the axial direction, and the stator core is fixed therein, and the rotor A support member that rotatably supports a distal end side of a rotating shaft fixed to the motor shaft and closes the opening on one axial side of the motor case, and a bottom wall side on the other axial side of the motor case. And a housing member that houses a control device that drives and controls the rotor, and a first motor case-side fixing portion provided in the motor case is supported by the support member. The second motor case side fixing portion fixed to the supporting member side fixing portion provided on the material and fixed to the outer peripheral surface of the motor case near the housing member is fixed to the housing member side fixing portion provided on the housing member. It is characterized by doing.

  According to the brushless motor of the present invention, a steel case is formed by pressing a steel plate, a motor case having a stator core fixed therein is provided, and the tip of a rotating shaft fixed to the rotor is provided on one side in the axial direction of the motor case. A support member that rotatably supports the side, a housing member that houses a control device that drives and controls the rotor is provided on the other side in the axial direction of the motor case, and the housing member is disposed on the outer peripheral surface of the motor case near the housing member. The motor case side fixing portion fixed to the provided housing member side fixing portion is fixed. Thus, even in a motor case in which a steel plate is press-formed into a cylindrical shape, the fixing of the housing member that houses the control device on the other side in the axial direction of the motor case is firmly fixed by the motor case side fixing portion and the housing member side fixing portion. Can be. Therefore, it is possible to form a motor case by pressing (drawing) a steel sheet, and simplifying the manufacturing process, such as eliminating the need for dimensioning (secondary work) compared to conventional aluminum motor cases. However, the manufacturing cost can be reduced. In addition, since a steel plate is used as compared with a conventional aluminum motor case that must be thick, the motor case can be thinned, and the brushless motor can be reduced in size and weight.

  According to the brushless motor of the present invention, the motor case side fixing portion is formed by press-molding a steel plate, and includes a fixing portion fixed to the housing member side fixing portion and a fixing portion fixed to the motor case. Are fixed to the motor case by welding, so that the motor case side fixing portion and the motor case can be made of the same steel plate and can be easily and reliably fixed to each other. Thereby, it can suppress that the manufacturing cost for adhering a motor case side fixing | fixed part and a motor case rises.

  According to the brushless motor of the present invention, the bottom wall is integrally provided on the other side of the motor case in the axial direction, the through hole through which the base end side of the rotating shaft passes is provided in the bottom wall, and the rotating shaft extending from the through hole is provided. Since the magnetic rotation sensor for detecting the rotation of the rotating shaft is arranged on the base end side, the leakage of magnetism generated when the brushless motor is driven can be blocked by the bottom wall (magnetic material) of the steel plate. . As a result, it is possible to reliably prevent malfunction of the magnetic rotation sensor and to suppress a decrease in detection accuracy of the magnetic rotation sensor.

  According to the brushless motor of the present invention, the motor case side step portion that is recessed radially inward near the housing member of the motor case is provided, and the housing member side step portion that is recessed radially outward is provided near the motor case of the housing member. The motor case and the housing member are coupled under the state where the motor case side step portion and the housing member side step portion are opposed to each other. As a result, even in a motor case in which a steel plate is pressed into a cylindrical shape, the path connecting the outside and the inside by the step part on the motor case side and the step part on the housing member side is a labyrinth shape, that is, a maze-like zigzag shape It can be formed easily, and it is difficult for rainwater, dust and the like to enter, and sealing performance can be secured.

  According to the brushless motor of the present invention, since the brushless motor is used as a drive source of the electric power steering apparatus, it can be applied to an electric power steering apparatus that requires low noise, low vibration, low cost and light weight. As a result, it can be easily mounted on a light vehicle or the like that requires low price and low fuel consumption.

It is explanatory drawing explaining the outline | summary of the electric power steering apparatus provided with the brushless motor which concerns on this invention. It is sectional drawing which shows the detailed structure of the brushless motor of FIG. It is a disassembled perspective view which decomposes | disassembles and shows the brushless motor of FIG. It is explanatory drawing explaining the adhering procedure to the motor case of a motor case side fixing | fixed part. It is a partial expanded sectional view which shows the connection part of a motor case and an accommodating member. It is an expanded sectional view of the broken-line circle | round | yen A part of FIG. It is explanatory drawing explaining the connection procedure of a motor case and an accommodating member.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is an explanatory view for explaining the outline of an electric power steering apparatus provided with a brushless motor according to the present invention, FIG. 2 is a sectional view showing a detailed structure of the brushless motor of FIG. 1, and FIG. 3 is a brushless motor of FIG. 4 is an exploded perspective view, FIG. 4 is an explanatory view for explaining a fixing procedure of the motor case side fixing portion to the motor case, and FIG. 5 is a partially enlarged sectional view showing a connecting portion between the motor case and the housing member. 6 is an enlarged cross-sectional view of the broken-line circle A portion of FIG. 5, and FIG. 7 is an explanatory diagram for explaining a connection procedure between the motor case and the housing member.

  As shown in FIG. 1, an electric power steering device 10 is mounted on a vehicle body (not shown) of a vehicle such as an automobile, and the electric power steering device 10 is connected to a steering wheel 11 operated by a driver. The steering shaft 12 assists the steering of the front wheels 13. The electric power steering device 10 is a so-called column assist type that is provided in the middle of the steering shaft 12 and is mounted at a predetermined location in a vehicle compartment (not shown).

  A pinion 15 is provided on the front wheel 13 side (lower side in the figure) of the steering shaft 12 via a universal joint 14, and the pinion 15 is meshed with a rack 17 formed integrally with the tie rod 16. These mechanisms are installed in a housing (not shown). As a result, the steering (rotational motion) of the steering wheel 11 is converted into the lateral movement (linear motion) of the tie rod 16 via the steering shaft 12, the universal joint 14, the pinion 15 and the rack 17, and as a result, The front wheel 13 is steered leftward or rightward.

  The electric power steering apparatus 10 includes a brushless motor 20 that is a drive source, and a speed reduction mechanism 30 that reduces the rotation of the brushless motor 20 to increase the torque. The brushless motor 20 includes a motor unit 40 and a controller unit 50. The motor unit 40 and the controller unit 50 are mechanically coupled to each other and integrated.

  The controller unit 50 is provided with a connection connector CN, and a wiring from the in-vehicle battery 18 is electrically connected to the connection connector CN. Thus, a drive current is supplied to the controller unit 50 by turning on an ignition switch (not shown). The connection connector CN is also electrically connected to wiring (not shown) from a torque sensor provided on the steering shaft 12. Thereby, the controller unit 50 calculates the assist amount (rotation speed, etc.) of the brushless motor 20 based on the detection signal from the torque sensor, and supplies the drive current reflecting the calculation result to the brushless motor 20. It has become.

  The speed reduction mechanism 30 includes a worm 31 provided so as to be integrally rotatable by a rotation shaft 46 of the brushless motor 20 and a connecting member 47 described later, and a worm wheel 32 that meshes with the worm 31 and rotates integrally with the steering shaft 12. Yes. The worm 31 and the worm wheel 32 are accommodated in a reduction gear case 33, and the reduction gear case 33 is connected to a bracket 48 as a support member of the brushless motor 20. As a result, the rotation of the rotation shaft 46 of the brushless motor 20 is decelerated to increase the torque and transmitted to the steering shaft 12 via the worm wheel 32.

  As shown in FIG. 2, the motor unit 40 forming the brushless motor 20 includes a motor case 41 formed into a bottomed cylindrical shape by press forming (deep drawing) a steel plate that is a magnetic material. . The motor case 41 includes a main body cylinder portion 41a, a first bottom wall (bottom wall) 41b, a second bottom wall (bottom wall) 41c, a third bottom wall (bottom wall) 41d, and a fourth bottom wall (bottom wall) 41e. The main body cylinder part 41a is open on one side in the axial direction (lower side in the figure). On the other hand, the other axial side (upper side in the drawing) of the main body cylinder portion 41a is closed by the bottom walls 41b, 41c, 41d, 41e. The third and fourth bottom walls 41d and 41e form a bearing support portion BS of a second bearing B2 to be described later. The bearing support portion BS is closer to the opening side of the motor case 41 than the first bottom wall 41b. Thus, an annular space AS is formed on the inner surface side of the motor case 41 on the first bottom wall 41b side.

  An annularly formed stator core 42 is fixed inside the main body cylinder portion 41a, and the stator core 42 has U, V, and W phase phases via an insulator 42a made of a non-magnetic material such as plastic. The coil 42b is wound with a predetermined winding method and the number of turns.

  Between the stator core 42 and the first bottom wall 41b, that is, in the annular space AS, a bus bar unit 43 as a current collector formed in an annular shape is provided in the same manner as the stator core 42. A plurality of conductive plates P are embedded by insert molding. One end of each conductive plate P is electrically connected to the end of a U, V and W phase coil 42b, and the other end of each conductive plate P is connected to a U, V and W phase coil 42b. A terminal socket 44 having three connection terminals 44a (see FIG. 3) corresponding to the above is electrically connected.

  Each connection terminal 44a is embedded in the terminal socket 44 by insert molding. The terminal socket 44 has a substantially arc-shaped bottom hole 41f (see FIG. 4) partially formed in the first bottom wall 41b. It penetrates and is fixed to the bottom hole 41f. Accordingly, the U, V and W phase coils 42b and the control device 52 accommodated in the accommodating member 51 can be electrically connected via the bottom hole 41f.

  A rotor 45 is provided inside the stator core 42 through a minute gap (air gap), and the rotor 45 rotates in the forward and reverse directions by supplying drive current to the U, V, and W phase coils 42b. It is like that. The rotor 45 is formed by laminating a plurality of annularly formed permanent magnets 45a, and each permanent magnet 45a is covered with a rotor case 45b made of a thin steel plate.

  A rotation shaft 46 is fixed through the rotation center of the rotor 45, that is, the rotation center of each permanent magnet 45a, and the rotation shaft 46 rotates integrally with the rotor 45. The distal end side (lower side in the figure) of the rotating shaft 46 is rotatably supported by a first bearing B1 provided on a bracket 48 that closes the opening side of the motor case 41. Here, a ball bearing (not shown in detail) is used as the first bearing B1.

  The distal end side of the rotating shaft 46 extends to the outside of the motor case 41 via the bracket 48, and a connecting portion formed in a cylindrical shape is connected to the distal end portion of the rotating shaft 46 that extends to the outside of the motor case 41. The member 47 is fitted and fixed. A serration portion 47a composed of a plurality of projections and depressions is formed on the inner side in the radial direction of the connecting member 47. The serration portion 47a is provided on the outer peripheral surface of the worm shaft 31a on the base end side (right side in FIG. 1). The serrated portion (not shown) is fitted and fixed, so that the rotating shaft 46 and the worm 31 can rotate together.

  The base end side (upper side in the figure) of the rotation shaft 46 extends through the through hole 41g (see FIG. 4) formed in the fourth bottom wall 41e and extends to the outside of the motor case 41. A sensor magnet part MG having a magnet magnetized in two directions in the rotation direction constituting the magnetic rotation sensor SE is fitted and mounted on the base end portion extending to the outside of the motor case 41 so as to be integrally rotatable. ing. Most of the sensor magnet part MG is formed of a second bottom wall 41c and a fourth bottom wall 41e (bearing support part BS) offset from the first bottom wall 41b of the motor case 41 in the axial direction. The end portion of the portion that is disposed in the columnar space CS and that is attached to the rotating shaft 46 reaches the through hole 41g, and thereby the dimension of the maximum axial protruding portion of the motor portion 40 can be reduced. While being able to make it small, the fitting strength of the sensor magnet part MG can also be maintained. In addition, for example, when the motor unit 40 and the controller unit 50 are connected, it is possible to prevent the controller unit 50 and the sensor magnet unit MG from inadvertently contacting each other, and thus prevent the sensor magnet unit MG from falling off. I have to.

  The second bearing B2 is mounted on the bearing support BS formed by the third and fourth bottom walls 41d and 41e, and the second bearing B2 is rotatable on the base end side of the rotating shaft 46. I support it. Here, a ball bearing (not shown in detail) is used as the second bearing B2.

  As described above, the bottom walls 41b, 41c, 41d, and 41e made of steel are arranged between the inner side and the outer side of the motor case 41, thereby making it difficult to leak the magnetism generated in the motor case 41 to the outside. ing. Therefore, since the adverse effect on the magnetic rotation sensor SE due to magnetism can be suppressed, the magnetic rotation sensor SE and the motor unit 40 are arranged close to each other, thereby minimizing an increase in the axial length of the brushless motor 20. Yes.

  One side of the motor case 41 in the axial direction, that is, the opening side is closed by an aluminum bracket 48 formed in a substantially disk shape by casting. The bracket 48 includes a fitting tube portion 48 a that is stamped and fitted into the opening portion of the motor case 41, and an abutting portion 48 b that is abutted against the flange portion 41 h of the motor case 41. Screw holes (not shown) are provided in a plurality of bracket side first extending portions 48d formed to extend radially outward from the abutting portions 48b of the bracket 48, and as shown in FIG. The fastening screw S1 is flanged with a plurality of flange side first extending portions 41j and bracket side first extending portions 48d formed to extend radially outward from the flange portion 41h of 41. The motor case 41 and the bracket 48 are connected by screwing through the screw hole 41k of the first side extension 41j. Thereby, the bracket 48 can be accurately positioned with respect to the motor case 41. The center portion of the bracket 48 is provided with a bearing fixing cylinder portion 48c to which the first bearing B1 is fixed, and the bracket 48 rotatably supports the rotating shaft 46 via the first bearing B1. Yes.

  A plurality of flange side second extending portions 41m formed to extend radially outward from the flange portion 41h of the motor case 41 are provided with holes 41n. Furthermore, the bracket 48 is provided with a plurality of second bracket side second extending portions 48e extending radially outward from the abutting portion 48b. The bracket side second extending portion 48e includes a flange side second extending portion 48e. A hole (not shown) that can face the hole 41n of the extending part 41m is provided. And the fastening screw which is not illustrated penetrates from the hole 41n side of the flange side 2nd extension part 41m on the state which faced the flange side 2nd extension part 41m and the bracket side 2nd extension part 48e. Then, the brushless motor 20 and the speed reduction mechanism 30 are coupled by screwing to the speed reducer case 33 (see FIG. 1).

  Reference numeral 48f denotes a fitting portion that fits with the reduction gear case 33 of the speed reduction mechanism 30 when the brushless motor 20 (bracket 48) is assembled to the speed reduction mechanism 30, and the speed reduction mechanism is included in the fitting portion 48f. An annular concave groove 48g is provided for disposing a seal member (not shown) such as an O-ring that seals between 30 and the like.

  As shown in FIGS. 3 and 4, on the outer peripheral surface of each bottom wall 41b, 41c, 41d, 41e of the motor case 41, that is, on the outer peripheral surface near the housing member 51 of the main body cylindrical portion 41a, Three motor case brackets (motor case side fixing portions) 49 are provided along the circumferential direction. The motor case brackets 49 are provided at substantially 90 ° intervals along the circumferential direction of the main body cylinder portion 41a, and are formed in the same shape.

  Each motor case bracket 49 is formed in a substantially L shape by press-molding a steel plate made of the same material as the motor case 41, and a fixing portion 49 a fixed to the main body cylinder portion 41 a and a fixing member side fixing of the storing member 51. A fixing portion 49b fixed to the portion 51e. The fixing portion 49b is provided with a screw hole 49c through which a fixing screw S2 for connecting and fixing the motor case 41 and the housing member 51 is passed. Further, a pair of reinforcing ribs 49d are provided between the fixing portion 49a and the fixing portion 49b, thereby increasing the strength of the motor case bracket 49 and preventing it from being deformed by an external force.

  As shown in FIG. 4, the adhering portion 49a is formed in a curved shape so as to have the same radius of curvature as that of the main body cylinder portion 41a so as to be in close contact with the main body cylinder portion 41a. This prevents a gap from being generated between the fixing portion 49a and the main body cylinder portion 41a. Here, the motor case bracket 49 is fixed to the motor case 41 by welding. Specifically, as shown by a broken line arrow in the drawing, first, the fixing portion 49a is exposed to a predetermined portion of the main body cylinder portion 41a. Then, the fixing portion 49a is brought into close contact with the main body cylinder portion 41a. And a required location is spot-welded using the welding tool T1 under the state.

  In addition, since the motor case bracket 49 and the motor case 41 are each formed with the steel plate of the same material, both can be fixed now easily and firmly. However, the fixing means for fixing the motor case bracket 49 and the motor case 41 is not limited to spot welding as described above, and may be other welding methods such as arc welding. Furthermore, fixing means such as a screw member may be used as long as the required fixing strength can be obtained.

  As a result, the motor case 41 and the motor case bracket 49 are firmly fixed, so that the connection between the motor case 41 and the housing member 51 is also strong, and noise, vibration, and the like are generated from the connection portion. It can be effectively suppressed.

  As shown in FIG. 2, the controller unit 50 that forms the brushless motor 20 includes an aluminum containing member 51. The housing member 51 is provided on the other side in the axial direction of the motor case 41 (upper side in the drawing) and is formed in a bottomed cylindrical shape having a cylindrical portion 51a and a bottom portion 51b. A control device 52 for driving and controlling the rotor 45 of the motor unit 40 is housed in the housing member 51.

  A terminal lead hole 51 c is formed in the cylindrical portion 51 a, and the terminal lead hole 51 c opens in a direction orthogonal to the axial direction of the rotation shaft 46. A resin connector connecting portion 51d that forms a connection connector CN is attached to the terminal lead hole 51c, and the connector connecting portion 51d has a wiring from an in-vehicle battery 18 (see FIG. 1) or a torque sensor. A connector (not shown) is connected.

  As shown in FIG. 3, three accommodating member side fixing portions 51e (only two are shown in the drawing) are provided on the outer peripheral surface of the cylindrical portion 51a near the motor case 41 along the circumferential direction of the cylindrical portion 51a. It is provided so as to protrude in the radial direction of 51a. Each accommodating member side fixing portion 51e is provided corresponding to each motor case bracket 49 at substantially 90 ° intervals along the circumferential direction of the main body cylinder portion 41a. Each accommodating member-side fixing portion 51e is integrally formed with the cylindrical portion 51a and has the same shape. Further, as shown in FIG. 5, each housing member side fixing portion 51e is formed with a female screw portion 51f to which a fixing screw S2 for connecting and fixing the motor case 41 and the housing member 51 is screwed. ing.

  As shown in FIG. 2, the control device 52 housed in the housing member 51 includes a power system substrate 53 disposed on the bottom 51 b side (upper side in the drawing) of the housing member 51, and the opening side of the housing member 51 ( And a control system board 54 arranged on the lower side in the drawing. On the power substrate 53, a plurality of semiconductor switching elements SW which are power elements, and electronic components such as capacitors and shunt resistors (none of which are shown) are mounted. Each semiconductor switching element SW is disposed so as to be in contact with the bottom 51b, so that heat generated when the brushless motor 20 is driven can be dissipated to the outside through the housing member 51. In other words, the housing member 51 has a function as a heat sink, and the housing member 51 is made of aluminum so as to function as a heat sink that easily dissipates heat of the power element to the outside.

  The power board 53 is provided with three female terminals 53a (only one is shown in the figure) that are electrically connected to each of the connection terminals 44a on the motor unit 40 side. When the motor case 41 and the housing member 51 are coupled to each female terminal 53a, each connection terminal 44a is inserted correspondingly.

  The power system board 53 is provided with a base end side of a plurality of connection terminals 53b (only one shown in the figure) being electrically connected, and the other end side of each connection terminal 53b is connected via a terminal extraction hole 51c. It is exposed inside the connector connecting portion 51d. And each connection terminal 53b is electrically connected with the wiring from the vehicle-mounted battery 18 (refer FIG. 1) and a torque sensor by connecting a vehicle body side connector to the connector connection part 51d.

  Further, one end side of a plurality of connection lines 53c (only one is shown in the figure) is electrically connected to the power system board 53, and the other end side of each connection line 53c is electrically connected to the control system board 54. It is connected. As a result, power is supplied to the control system board 54, and a control signal from the control system board 54 is transmitted to the power system board 53.

  The control system board 54 faces the first bottom wall 41b of the motor case 41, and an MR sensor 54a constituting the magnetic rotation sensor SE is provided at a substantially central portion of the control system board 54 on the first bottom wall 41b side. Has been implemented. Here, the magnetic rotation sensor SE is composed of an MR sensor 54a and a sensor magnet portion MG mounted on the rotation shaft 46, and both are opposed to each other with a minute distance (air gap). The magnetic rotation sensor SE is a non-contact type, and the MR sensor 54a generates a pulse signal by the rotation of the sensor magnet unit MG and transmits the pulse signal to a CPU (not shown) mounted on the control system board 54. It is like that. That is, the CPU can calculate the rotation angle of the rotation shaft 46 by counting the number of pulses of the pulse signal from the MR sensor 54a, and can calculate the rotation number of the rotation shaft 46 by looking at the appearance timing of the pulse signal. It has become.

  As shown in FIGS. 5 and 6, a seal mechanism 60 is provided between the motor case 41 and the housing member 51 to prevent intrusion of rainwater, dust, and the like from the outside, thereby damaging the control device 52. And the detection accuracy of the magnetic rotation sensor SE is prevented from being lowered. The seal mechanism 60 is formed of a motor case side step portion 61, a housing member side step portion 62, and an O-ring 63 as a seal member.

  The step part 61 on the motor case side is provided near the housing member 51 of the main body cylinder part 41 a forming the motor case 41, that is, closer to the first bottom wall 41 b of the main body cylinder part 41 a, and is recessed radially inward of the motor case 41. It is provided in an annular shape. The motor case side stepped portion 61 is recessed toward the inner side in the radial direction of the motor case 41 and provided in an annular shape so as to open toward the housing member side stepped portion 62 of the housing member 51. The motor case side step portion 61 includes a first wall portion 61a extending in the radial direction of the motor case 41 on the main body cylinder portion 41a side, and a second wall portion 61b extending in the axial direction of the motor case 41 on the first bottom wall 41b side. Formed from.

  The accommodating member side stepped portion 62 is provided near the motor case 41 of the cylindrical portion 51 a forming the accommodating member 51, that is, near the accommodating member side fixing portion 51 e of the cylindrical portion 51 a, and is recessed to the outside in the radial direction of the accommodating member 51. It is provided in an annular shape. The housing member side step portion 62 is recessed toward the outside in the radial direction of the housing member 51 and is provided in an annular shape so as to open toward the motor case side step portion 61 of the motor case 41. The accommodating member side stepped portion 62 includes a third wall portion 62a extending in the radial direction of the accommodating member 51 on the bottom portion 51b side, and a fourth wall portion 62b extending in the axial direction of the accommodating member 51 on the accommodating member side fixing portion 51e side. Is formed.

  The O-ring 63 has a circular cross section made of a flexible elastic material (rubber material or the like). The O-ring 63 is provided between the motor case side stepped portion 61 and the housing member side stepped portion 62, that is, between the opening side of the motor case side stepped portion 61 and the opening side of the housing member side stepped portion 62 in the radial direction. It is arranged under a pressed state (elastically deformed state). Accordingly, the O-ring 63 is in close contact with both the second wall portion 61 b of the motor case side step portion 61 and the fourth wall portion 62 b of the housing member side step portion 62.

  Thus, by providing the O-ring 63 in close contact with both the second wall portion 61b and the fourth wall portion 62b, the O-ring 63 has a radial dimension of the second wall portion 61b and the fourth wall portion 62b. The gap between the motor case 41 and the housing member 51 is securely sealed while absorbing the error. Further, since the motor case side stepped portion 61 and the housing member side stepped portion 62 are opposed to each other and the O-ring 63 is disposed therebetween, the intrusion path for rainwater, dust, etc. is indicated by a broken line arrow in FIG. As shown, it can have a labyrinth shape, that is, a maze-like zigzag shape, and more effectively suppress the intrusion of rainwater or dust. Therefore, depending on the specifications (degrees) of the waterproof / dustproof function of the brushless motor 20, only the labyrinth shape is sufficient, and when the brushless motor 20 is disposed in a wet environment or in a dust environment, the O The ring 63 can be selectively arranged.

  Here, the positioning of the motor case 41 and the housing member 51, that is, the mounting depth of the housing member 51 with respect to the motor case 41 is determined by the contact between the motor case bracket 49 of the motor case 41 and the housing member side fixing portion 51 e of the housing member 51. Set by Thereby, the O-ring 63 is not crushed and damaged by the first wall portion 61a of the motor case side step portion 61 and the third wall portion 62a of the housing member side step portion 62.

  Next, the assembly procedure of the brushless motor 20 formed as described above will be described in detail with reference to the drawings.

  First, as shown in FIG. 3, a motor unit 40 and a controller unit 50 assembled in separate assembly steps are prepared. Further, an O-ring 63 that forms the seal mechanism 60, three fixing screws S2, and a fastening tool T2 (see FIG. 7) for fastening each fixing screw S2 are prepared. Here, each fixing screw S2 is a special screw, and is not a general-purpose plus screw or minus screw, but has a substantially star-shaped recess at the screw head as shown in FIG. Therefore, the fastening tool T2 is a special tool dedicated to each fixing screw S2. Thus, the brushless motor 20 cannot be easily disassembled (non-decomposition type).

  Then, as shown in FIG. 3, the O-ring 63 is mounted on the motor case side stepped portion 61 of the motor unit 40 so that the shaft core of the motor unit 40 and the shaft core of the O-ring 63 are aligned. Here, in order to ensure the sealing performance of the O-ring 63, the O-ring 63 is prevented from being twisted. Thereafter, the controller 50 is put on the motor unit 40 so that the shaft core of the motor unit 40 to which the O-ring 63 is attached is aligned with the shaft core of the controller unit 50. Here, the accommodating member side fixing portions 51e of the controller unit 50 are opposed to the motor case brackets 49 of the motor unit 40, respectively. Then, as shown in FIG. 2, each female terminal 53 a of the control device 52 and each connection terminal 44 a of the terminal socket 44 face each other.

  Next, the controller unit 50 faces the motor unit 40, and the cylinder portion 51 a of the housing member 51 is stamped and fitted into the main body cylinder portion 41 a of the motor case 41. As a result, the O-ring 63 is surrounded by the first wall portion 61a and the second wall portion 61b of the motor case side step portion 61 and the third wall portion 62a and the fourth wall portion 62b of the housing member side step portion 62. The seal mechanism 60 is formed in the space (see FIG. 6). Further, along with the formation of the seal mechanism 60, each connection terminal 44a enters into each female terminal 53a and is electrically connected thereto.

  Thereafter, the housing case-side fixing portions 51e of the housing member 51 and the fixing portions 49b of the motor case brackets 49 are brought into contact with each other by further proceeding with the stamping fitting between the motor case 41 and the housing member 51. Thereby, the seal stamp fitting of the accommodating member 51 to the motor case 41 is completed. Here, with the completion of the seal fitting of the housing member 51 to the motor case 41, the separation distance (see FIG. 2) between the sensor magnet portion MG of the magnetic rotation sensor SE and the MR sensor 54a is optimized. It is arranged to face each other with a minute distance (air gap).

  Then, as shown in FIGS. 5 and 7, each fixing screw S2 is inserted into the screw hole 49c of the motor case bracket 49 while the fixing screw S2 is inserted into the accommodating member side fixing portion 51e using the fastening tool T2. The female screw part 51f is screwed. As a result, the motor case 41 and the housing member 51 are connected, and as a result, the motor unit 40 and the controller unit 50 are integrated to complete the brushless motor 20.

  Thereafter, the completed brushless motor 20 includes a plurality of flange-side second extending portions 41m that are formed to extend radially outward from the flange portion 41h of the motor case 41, and an abutting portion 48b of the bracket 48. Are connected to the speed reducer case 33 of the speed reduction mechanism 30 by fastening screws (not shown) through holes (not shown) of the plurality of bracket side second extending portions 48e formed to extend radially outward from The

  As described above in detail, according to the brushless motor 20 according to the present embodiment, a motor case 41 in which a steel plate is press-formed and formed into a cylindrical shape and a stator core 42 is fixed inside is provided. A bracket 48 that rotatably supports the distal end side of the rotating shaft 46 fixed to the rotor 45 is provided on one side in the direction, and a control device 52 that drives and controls the rotor 45 is housed on the other side in the axial direction of the motor case 41. The housing member 51 was provided, and the motor case bracket 49 fixed to the housing member side fixing portion 51 e provided on the housing member 51 was fixed to the outer peripheral surface of the motor case 41 near the housing member 51.

  Thereby, even if it is the motor case 41 which press-formed the steel plate in the cylinder shape, the accommodation member 51 which accommodated the control apparatus 52 in the other axial direction side of the motor case 41 by the motor case bracket 49 and the accommodation member side fixing | fixed part 51e. Can be firmly fixed. Therefore, the motor case 41 can be formed by pressing (drawing) a steel plate, and the manufacturing process is simplified, such as eliminating the need for dimensioning work (secondary work) compared to the conventional aluminum motor case. Manufacturing cost can be reduced. In addition, the motor case 41 can be made thinner because a steel plate is used as compared with a conventional aluminum motor case that must be thick, and thus the brushless motor 20 can be made smaller and lighter. it can.

  Further, according to the brushless motor 20 according to the present embodiment, the motor case bracket 49 is formed by press-molding a steel plate, and is fixed to the fixing part 49b and the motor case 41 fixed to the housing member side fixing part 51e. Since the fixing part 49a is fixed to the motor case 41 by welding and the motor case bracket 49 and the motor case 41 are made of the same steel plate, they can be easily and reliably fixed to each other. Thereby, it can suppress that the manufacturing cost for adhering the motor case bracket 49 and the motor case 41 rises.

  Furthermore, according to the brushless motor 20 according to the present embodiment, the first bottom wall 41b, the second bottom wall 41c, the third bottom wall 41d, and the fourth bottom wall 41e are integrally formed on the other side in the axial direction of the motor case 41. A through-hole 41g through which the base end side of the rotary shaft 46 passes is provided in the fourth bottom wall 41e, and the rotation of the rotary shaft 46 is detected on the base end side of the rotary shaft 46 extending from the through hole 41g. A rotation sensor SE was arranged. Thereby, the leakage to the outside of the magnetism generated when the brushless motor 20 is driven can be blocked by the bottom walls 41b, 41c, 41d, 41e (magnetic material) of the steel plate. Therefore, it is possible to reliably prevent malfunction of the magnetic rotation sensor SE and to suppress a decrease in detection accuracy of the magnetic rotation sensor SE.

  Moreover, according to the brushless motor 20 according to the present embodiment, the motor case side step portion 61 that is recessed radially inward is provided near the housing member 51 of the motor case 41, and the radial direction is provided near the motor case 41 of the housing member 51. The housing member-side stepped portion 62 that is recessed outside is provided, and the motor case 41 and the housing member 51 are coupled together in a state where the motor case-side stepped portion 61 and the housing member-side stepped portion 62 face each other. Thereby, even in the motor case 41 formed by pressing a steel plate into a cylindrical shape, the path connecting the outside and the inside by the motor case side step portion 61 and the housing member side step portion 62 is a labyrinth shape, that is, a maze shape. It can be formed in a zigzag shape, making it difficult for rainwater, dust, etc. to enter, and ensuring sealing performance.

  Furthermore, according to the brushless motor 20 according to the present embodiment, since the brushless motor 20 is used as a drive source of the electric power steering apparatus 10, an electric power steering apparatus that is required to have low noise, low vibration, low cost, and light weight. (EPS) can also be supported. As a result, it can be easily mounted on a light vehicle or the like that requires low price and low fuel consumption.

  It goes without saying that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. For example, in the above embodiment, the brushless motor 20 is applied to the column assist type electric power steering apparatus 10 provided in the middle of the steering shaft 12, but the present invention is not limited to this, and the pinion 15 ( The present invention can also be applied to an electric power steering apparatus that assists the tie rod 16 (refer to FIG. 1).

  Moreover, although the case where the brushless motor 20 is used as a drive source of the electric power steering apparatus 10 has been described in the above embodiment, the present invention is not limited to this, for example, driving of engine auxiliary equipment such as an oil pump motor. It can also be used as a source.

DESCRIPTION OF SYMBOLS 10 Electric power steering apparatus 11 Steering wheel 12 Steering shaft 13 Front wheel 14 Universal joint 15 Pinion 16 Tie rod 17 Rack 18 Vehicle-mounted battery 20 Brushless motor (drive source)
DESCRIPTION OF SYMBOLS 30 Deceleration mechanism 31 Worm 31a Worm shaft 32 Worm wheel 33 Reduction gear case 40 Motor part 41 Motor case 41a Main body cylinder part 41b 1st bottom wall (bottom wall)
41c 2nd bottom wall (bottom wall)
41d Third bottom wall (bottom wall)
41e 4th bottom wall (bottom wall)
41f Bottom hole 41g Through hole 41h Flange portion 41j Flange side first extending portion 41k Screw hole 41m Flange side second extending portion 41n Hole portion 42 Stator core 42a Insulator 42b Coil 43 Bus bar unit (current collector)
44 Terminal socket 44a Connection terminal 45 Rotor 45a Permanent magnet 45b Rotor case 46 Rotating shaft 47 Connecting member 47a Serration part 48 Bracket (supporting member)
48a Fitting cylinder part 48b Abutting part 48c Bearing fixing cylinder part 48d Bracket side first extension part 48e Bracket side second extension part 48f Fitting part 48g Annular groove 49 Motor case bracket (motor case side fixing part)
49a Adhering portion 49b Fixing portion 49c Screw hole 49d Reinforcing rib 50 Controller portion 51 Housing member 51a Tube portion 51b Bottom portion 51c Terminal lead-out hole 51d Connector connection portion 51e Housing member side fixing portion 51f Female screw portion 52 Control device 53 Power system board 53a Type terminal 53b Connection terminal 53c Connection line 54 Control system board 54a MR sensor 60 Seal mechanism 61 Motor case side step part 61a First wall part 61b Second wall part 62 Housing member side step part 62a Third wall part 62b Fourth wall part 63 O-ring (seal member)
P conductive plate AS annular space BS bearing support portion CS cylindrical space B1 first bearing B2 second bearing CN connection connector SE magnetic rotation sensor SW semiconductor switching element MG sensor magnet portion S1 fastening screw S2 fixing screw T1 welding tool T2 fastening tool

Claims (7)

A brushless motor for an electric power steering apparatus comprising a stator core and a rotor that rotates in the stator core,
A bottomed cylindrical motor case comprising a press-formed steel plate, having an opening on one side in the axial direction, a bottom wall integrally provided on the other side in the axial direction, and having the stator core fixed therein ,
A support member that rotatably supports a distal end side of a rotating shaft fixed to the rotor, and that closes the opening on one side in the axial direction of the motor case;
A housing member that is provided on the bottom wall side on the other side in the axial direction of the motor case and houses a control device that drives and controls the rotor ;
A first motor case side fixing portion provided in the motor case and fixed to a supporting member side fixing portion provided in the supporting member;
Provided in the motor case, and a second motor case side fixing portion fixed to the housing member-side fixing portion provided on the accommodating member,
Have
The brushless motor for an electric power steering apparatus, wherein the second motor case side fixing portion is fixed to an outer peripheral surface of the motor case near the housing member . The electric power brushless motor steering system of claim 1, wherein the second motor case-side fixing portion is made of steel sheet obtained by press molding, a fixed portion fixed to the housing member-side fixing portion, wherein brushless motor for an electric power steering apparatus characterized in that it comprises a fixing portion which is welded to the motor case, the. The electric power brushless motor steering system according to claim 1 or 2, wherein the first motor case-side fixing portion is a flange portion provided on the outer periphery of the opening in one axial side of the motor case, brushless motor for an electric power steering apparatus according to claim Tei Rukoto the support member is attached to the flange portion. In the brushless motor for an electric power steering apparatus according to claim 1, wherein the support member is characterized Tei Rukoto coupled to the deceleration mechanism for decelerating the rotation of the rotary shaft electric Brushless motor for power steering device . In the brushless motor for an electric power steering apparatus according to claim 1, wherein the bottom wall through holes are provided to the base end side of the rotary shaft passes, extending from the through hole wherein the base end side of the rotary shaft, an electric power steering apparatus brushless motor according to claim Rukoto magnetic rotation sensor for detecting rotation of said rotary shaft are arranged. In the brushless motor for an electric power steering apparatus according to claim 1, wherein the motor case side step portion in the housing member toward the recessed radially inwardly of the motor casing is provided, the accommodating member the accommodation member side stepped portion recessed radially outward to the motor case closer is provided, and said housing member side step portion and the motor case side stepped portion at the opposite is not the state of the housing and the motor casing brushless motor for an electric power steering apparatus in which a member is characterized that you have been connected. A method for manufacturing a brushless motor for an electric power steering apparatus comprising a stator core and a rotor that rotates within the stator core,
A bottomed cylindrical shape in which a steel plate is press-formed and formed into a cylindrical shape, an opening is provided on one side in the axial direction, a bottom wall is integrally provided on the other side in the axial direction, and the stator core is fixed inside Motor case,
A support member that rotatably supports a distal end side of a rotating shaft fixed to the rotor, and that closes the opening on one side in the axial direction of the motor case;
A housing member that is provided on the bottom wall side on the other side in the axial direction of the motor case and houses a control device that drives and controls the rotor;
Prepare
Fixing the first motor case side fixing portion provided in the motor case to the supporting member side fixing portion provided in the supporting member;
A brushless motor for an electric power steering apparatus, wherein a second motor case side fixing portion fixed to an outer peripheral surface of the motor case near the housing member is fixed to a housing member side fixing portion provided in the housing member. Manufacturing method.

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