JP4198723B2 - Brushless motor for electric power steering system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a brushless motor for an electric power steering device capable of preventing a rotor from biting foreign matter and being non-rotatable without increasing the number of parts and assembling man-hour. <P>SOLUTION: This brushless motor assists steering force of a steering wheel through a shaft 9 connected to a steering mechanism of a vehicle. A holder bulkhead 5a having a distal end part extending toward an internal surface wall of a housing 1 and abutting on the wall is formed on an inner diameter side of a holder 5. By the holder bulkhead 5a, foreign matter is prevented from entering an air gap between a stator 4 and the rotor 11 by passing through a gap between the holder 5 and the housing 1. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention relates to a brushless motor for an electric power steering apparatus that assists the steering force of a steering wheel of a vehicle.

  Conventionally, a housing, a bottomed cylindrical frame with a peripheral edge fixed to the housing, a stator having a motor coil fixed to an inner wall surface of the frame and provided in a core and a slot of the core via a bobbin A shaft rotatably provided on the center axis of the stator; a rotor provided on the shaft that rotates together with the shaft in response to a rotating magnetic field generated by a current flowing in the motor coil; and the shaft on one side surface of the stator A holder formed with a plurality of grooves extending in the circumferential direction, a terminal of each phase of the motor coil provided in each of the grooves, and an anti-stator side of the holder. , A nut to which a screw is screwed, and a bus bar connected to a power supply line and a bus bar side terminal connected by the screw. A connecting portion protruding from the terminal along the axial direction of the shaft and passing through a base connected to the bus bar side terminal. A brushless motor for an electric power steering device that assists steering force is known (for example, see Patent Document 1).

JP 2003-204654 A

  In this case, for example, a screw hole for screwing the bus bar with the bus bar side terminal and a screw is formed in the housing, and a foreign object such as a metal piece enters the inside through the screw hole and the stator and rotor are in contact with each other. It is conceivable that the air gap is reached and the rotor bites in the foreign matter and becomes unable to rotate.

  An object of the present invention is to solve the above-described problems, and it is possible to prevent the rotor from getting stuck and becoming unable to rotate without increasing the number of parts and the number of assembling steps. It is an object of the present invention to obtain a brushless motor for an electric power steering device that can be used.

  In the brushless motor for an electric power steering apparatus according to the present invention, a housing, a bottomed cylindrical frame having a peripheral edge fixed to the housing, a bobbin fixed to an inner wall surface of the frame, and a core and a slot of the core A stator having a motor coil provided via the shaft, a shaft rotatably provided on the central axis of the stator, and a shaft that rotates together with the shaft in response to a rotating magnetic field that is provided on the shaft and is generated by a current flowing through the motor coil. A rotor, a holder fixed on one side surface of the stator so as to surround the shaft, and a plurality of grooves extending in the circumferential direction, and terminals of each phase of the motor coil provided in each of the grooves And a nut provided on the side opposite to the stator of the holder, to which a screw is screwed, and a power line A bus bar connected to the bus bar and connected to the bus bar side terminal through the connecting portion protruding from the terminal along the axial direction of the shaft; In a brushless motor for an electric power steering apparatus that assists a steering force of a steering wheel through the shaft connected to a steering mechanism of a vehicle, a tip portion extends toward an inner wall of the housing and abuts on an inner diameter side of the holder The holder partition wall is formed, and the holder partition wall prevents foreign matter from entering the air gap between the stator and the rotor through the gap between the holder and the housing.

  According to the brushless motor for an electric power steering apparatus of the present invention, it is possible to prevent the rotor from getting stuck with foreign matter and becoming unable to rotate.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or equivalent members and parts will be described with the same reference numerals.
Embodiment 1 FIG.
1 is a side sectional view showing a brushless motor (hereinafter abbreviated as a motor) for an electric power steering apparatus according to Embodiment 1 of the present invention, FIG. 2 is a left side view of FIG. 1, and FIG. It is a fragmentary sectional view along the III line (however, the motor coil 17 is omitted).

The motor includes a housing 1 made of a material such as aluminum, a bottomed cylindrical frame 3 having a peripheral edge fixed to the housing 1 with screws 2, and a stator 4 fixed to the inner wall surface of the frame 3. And a holder 5 fixed to one side surface of the stator 4 and a base 6 provided on the side opposite to the stator 4 of the holder 5.
In addition, the motor is arranged on the center axis of the housing 1 and the frame 3 and is rotatably supported by the front bearing 7 and the rear bearing 8, and the N pole and the S pole magnet 10 are alternately bonded to the shaft 9. The rotor 11 whose outer peripheral surface is covered with a protective tube (not shown), the boss 12 that is press-fitted into the end of the shaft 9 and connected to the steering mechanism (not shown), and the boss 12 and the shaft 9 are press-fitted. And a resolver 14 that is a rotational position sensor that is provided between the bush 13 and detects the rotational angle of the shaft 9.

  The stator 4 includes a core 15 in which silicon steel sheets are laminated and slots 51 extending in the axial direction are formed at intervals in the circumferential direction, and a conductor is wound around the slots 51 of the core 15 via the bobbin 16. And a motor coil 17 configured as described above. The U phase coil portion, the V phase coil portion, and the W phase coil portion of the motor coil 17 are star-connected, and the common side of each coil portion is connected to the common terminal 18 by fusing.

As shown in FIG. 4, the holder 5 is formed with four grooves extending in the circumferential direction and having different diameters. W-phase terminal 20, V-phase terminal 21 and U-phase terminal 22 are accommodated in these grooves, respectively. The W-phase terminal 20, the V-phase terminal 21, and the U-phase terminal 22 have a band shape when deployed in a planar shape, and have a circular shape when they are accommodated in the respective grooves. These terminals 20, 21 and 22 are connected to respective end portions of the W-phase coil portion, V-phase coil portion and U-phase coil portion of the motor coil 17.
Each of the W-phase terminal 20, the V-phase terminal 21, and the U-phase terminal 22 has a connecting portion 23 that extends in the axial direction.

  The base 6 is configured by insert-molding a bus bar side terminal 32 connected to the bus bar 30 with screws 31 and a nut 19 (see FIG. 13) to which the screws 31 are screwed. The bus bar side terminal 32 in surface contact with the bus bar 30 is exposed. In addition, the base 6 is formed with an insertion port 50 (see FIG. 13) into which a connecting portion 23 extending in the axial direction is inserted from the W-phase terminal 20, the V-phase terminal 21, and the U-phase terminal 22, respectively. The distal end portion of the connecting portion 23 is connected to the bus bar side terminal 32 by TIG welding after passing through the insertion port 50. Each bus bar 30 is connected to a power line 45.

  The resolver 14 includes an elliptical resolver rotor 33 that is press-fitted into the shaft 9, and a resolver stator 34 that surrounds the resolver rotor 33.

The front bearing 7 on the housing 1 side has the outer ring portion of the front bearing 7 fixed to the housing 1 by caulking.
The stator 4 is press-fitted into a cup-shaped frame 3 manufactured by drawing an iron plate, and a bearing box 35 that houses and holds a rear bearing 8 is formed on the bottom surface of the frame 3.
A hole 3 </ b> A used when the housing 1 and the frame 3 are fitted is formed in the bottom surface of the frame 3. A rubber cap 36 for securing waterproofing in the motor is attached to the hole 3A.

The housing 1 has a frame-side fitting portion 37 that fits the frame 3 on one end surface, and a gear-side fitting portion 38 that fits a steering gear-side housing (not shown) on the other end surface. ing.
The gear-side fitting portion 38 of the housing 1 is waterproofed by an O-ring (not shown) provided in the gear box on the steering gear side. Water and dust are transferred from the gear-side fitting portion 38 into the motor. Etc. are prevented from entering.
The frame-side fitting portion 37 of the housing 1 is provided with an O-ring 39 that is a seal member to ensure waterproofness.

The resolver stator 34 is fixed to the housing 1 by a pair of screws 40.
The resolver stator 34 is provided with a connector 41 for signal connection. A signal line 42 is led out from the connector 41. A signal line 42 for transmitting a position detection signal from the resolver 14 to a control circuit unit (not shown) is fixed to the housing 1 by a clamp 43 (see FIG. 11).
Inside the gear side fitting portion 38 of the housing 1, three screw holes 44 are formed so that the screw 31 can be turned from the outside when the bus bar 30 is screwed to the base 6.

  In the brushless motor for an electric power steering apparatus having the above configuration, a current flows through the motor coil 17 through the power supply line 45, and a rotating magnetic field is generated in the motor coil 17. The rotor 11 rotates in response to this rotating magnetic field, and this rotational force is transmitted to the steering mechanism via the shaft 9 and is used for torque assist of the steering mechanism.

By the way, in the motor having the above configuration, as shown in FIG. 5, the tip portion is formed on the inner wall of the housing 1 on the inner diameter side of the holder 5, as clearly shown in comparison with the conventional holder 5 </ b> A shown in FIG. 6. An abutting holder partition wall 5a is formed. Therefore, when a foreign object such as a metal piece enters the motor along the path (first path) indicated by the thick line A in FIG. 1, the foreign object is prevented from further intrusion by the holder partition 5a. .
Further, even when the clamp 43 holding the signal line 42 is broken, the signal line 42 is prevented from moving toward the shaft 9 by the holder partition wall 5a and is not caught in the rotating shaft 9.

In addition, one flange 16a on the inner diameter side on the holder 5 side of the bobbin 16 extends and contacts the bottom surface of the holder 5, and the other flange 16b on the inner diameter side on the opposite holder 5 side The tip portion extends toward and contacts the inner wall of the bottom surface of the frame 3.
Further, unlike the conventional bobbin 16A shown in FIG. 7, as shown in FIG. 3, the bottom surface of the slot 51 is covered with the bobbin 16, and the flanges 16a and 16b are ring-shaped, There is no gap.
Therefore, when a foreign object such as a metal piece enters the motor along the path (second path) indicated by the thick line B in FIG. 1, the foreign object is prevented from further entering by the flange 16a.
Further, when a foreign object such as a metal piece enters the motor along the path (third path) shown in FIG. 1 through the recess 15a formed on the outer peripheral surface of the core 15, Foreign matter is prevented from further intrusion at the flange 16b. In addition to the recess 15a, there is a path through which the foreign matter reaches the flange 16b through the slot 51.

According to the motor of this embodiment, when it enters the motor from the housing 1 through the hole 44 and the gap 52 in the vicinity of the signal connection connector 41, it reaches the air gap between the stator 4 and the rotor 11. In front, the holder partition wall 5a and the flanges 16a and 16b prevent entry, and the mechanical lock of the rotor 11 is prevented.
Further, the holder partition wall 5a and the flanges 16a and 16b are not new parts, and it is not necessary to increase the number of parts and the number of assembling steps.

Embodiment 2. FIG.
FIG. 8 is a side sectional view showing a motor according to Embodiment 2 of the present invention.
In this embodiment, one end of the holder partition wall 5b of the holder 5 extends and contacts the inner wall surface of the housing 1, and the other end extends and contacts the flange 16c of the bobbin 16.
Other configurations are the same as those of the first embodiment.
In this embodiment, when a foreign object such as a metal piece enters the motor along the first path and the second path, the foreign object is prevented from further entering by the holder partition wall 5b. The
Further, when a foreign object such as a metal piece enters along the third path, further intrusion is prevented by the flange 16b of the bobbin 16 as in the first embodiment.

Embodiment 3 FIG.
9 is a side sectional view showing a motor according to Embodiment 3 of the present invention, FIG. 10 is a view when the motor of FIG. 9 is disassembled into the housing 1 side and the frame 3 side, and FIG. 11 is FIG. FIG. 12 is a diagram when FIG. 10 is viewed in the arrow B direction.
In this embodiment, as shown in FIG. 13, a ring-shaped base partition wall 6a is formed on the base 6A. One end of the base partition wall 6a surrounding the shaft 9 extends to the inner wall surface of the housing 1, and the other end extends to the holder 5A.
Other configurations are the same as those of the first embodiment.
In this embodiment, the base partition wall 6a prevents foreign matter from entering along the first path, like the holder partition wall 5a of the first embodiment.

Embodiment 4 FIG.
14 is a side sectional view showing a motor according to Embodiment 4 of the present invention, and FIG. 15 is a view when the frame 3 side of the motor is viewed in the same direction as that of FIG. 12 shown in Embodiment 3.
In this embodiment, the base 6B has a ring-shaped base partition wall 6a and a cover wall 6b that covers the holder 5A. The cover wall 6 b extends to the inner wall surface of the housing 1 and is in contact therewith.
Other configurations are the same as those of the first embodiment.
In this embodiment, even if foreign matter enters the motor through the hole 44 and the gap 52 near the signal connection connector 41 from the housing 1 side, the holder 5A is formed by the base partition wall 6a and the cover wall 6b of the base 6B. Further intrusion is prevented, and foreign matter does not reach the air gap between the stator 4 and the rotor 11.

  In each of the above embodiments, the brushless motor for an electric power steering apparatus in which the motor and the control circuit unit provided with the power element for driving the motor are separated has been described. However, the motor and the control circuit unit are different from each other. Of course, the present invention can also be applied to an integrated brushless motor for an electric power steering apparatus.

It is a sectional side view which shows the brushless motor for electric power steering apparatuses of Embodiment 1 of this invention. It is a left view of FIG. It is arrow sectional drawing along the III-III line | wire of FIG. It is a front view of the holder of FIG. It is arrow sectional drawing along the VV line of the holder of FIG. It is sectional drawing of the conventional holder. It is principal part sectional drawing which shows the conventional brushless motor. It is a sectional side view which shows the brushless motor for electric power steering apparatuses of Embodiment 2 of this invention. It is a sectional side view which shows the brushless motor for electric power steering apparatuses of Embodiment 3 of this invention. FIG. 10 is an exploded view of the brushless motor for the electric power steering apparatus of FIG. 9. It is a figure when FIG. 10 is seen from the arrow A. It is a figure when FIG. 10 is seen from the arrow B. It is a front view of the base of FIG. It is a sectional side view which shows the brushless motor for electric power steering apparatuses of Embodiment 4 of this invention. It is a principal part front view of FIG.

Explanation of symbols

  1 housing, 3 frame, 4 stator, 5 holder, 5a, 5b holder partition, 6, 6A, 6B base, 6a base partition, 6b covering wall, 9 shaft, 10 magnet, 11 rotor, 16 bobbin, 16a, 16b, 16c Flange, 19 Nut, 20 U-phase terminal, 21 V-phase terminal, 22 W-phase terminal, 23 connection, 30 bus bar, 31 screw, 32 bus bar terminal, 45 power line.

Claims (6)

A housing;
A bottomed cylindrical frame with a peripheral edge fixed to the housing;
A stator having a motor coil fixed to an inner wall surface of the frame and provided in a core and a slot of the core via a bobbin;
A shaft rotatably provided on the central axis of the stator;
A rotor that rotates with the shaft according to a rotating magnetic field that is provided on the shaft and is generated by a current flowing through the motor coil;
A holder that is fixed so as to surround the shaft on one side surface of the stator and has a plurality of grooves extending in the circumferential direction;
A terminal for each phase of the motor coil provided in each groove;
A nut provided on the side opposite to the stator of the holder and screwed, a bus bar connected to a power supply line, and a bus bar side terminal connected by the screw, from the terminal along the axial direction of the shaft And a base that protrudes through and connects to the bus bar side terminal,
In a brushless motor for an electric power steering device that assists a steering force of a handle through the shaft connected to a steering mechanism of a vehicle,
On the inner diameter side of the holder, a holder partition wall is formed in which a tip portion extends toward and contacts the inner wall of the housing,
A brushless for an electric power steering apparatus, wherein the holder partition prevents foreign matter from entering the air gap between the stator and the rotor through a gap between the holder and the housing. Brushless motor for motors. A housing;
A bottomed cylindrical frame with a peripheral edge fixed to the housing;
A stator having a motor coil fixed to an inner wall surface of the frame and provided in a core and a slot of the core via a bobbin;
A shaft rotatably provided on the central axis of the stator;
A rotor that rotates with the shaft according to a rotating magnetic field that is provided on the shaft and is generated by a current flowing through the motor coil;
A holder that is fixed so as to surround the shaft on one side surface of the stator and has a plurality of grooves extending in the circumferential direction;
A terminal for each phase of the motor coil provided in each groove;
A nut provided on the side opposite to the stator of the holder and screwed, a bus bar connected to a power supply line, and a bus bar side terminal connected by the screw, from the terminal along the axial direction of the shaft And a base that protrudes through and connects to the bus bar side terminal,
In a brushless motor for an electric power steering device that assists a steering force of a handle through the shaft connected to a steering mechanism of a vehicle,
On the inner diameter side of the holder, a holder partition is formed in which one end extends toward the inner wall of the housing and abuts, and the other end extends toward the bobbin and abuts.
The holder partition prevents foreign matter from entering the air gap between the stator and the rotor through the gap between the holder and the housing and the gap between the holder and the stator. A brushless motor for an electric power steering apparatus. A housing;
A bottomed cylindrical frame with a peripheral edge fixed to the housing;
A stator having a motor coil fixed to an inner wall surface of the frame and provided in a core and a slot of the core via a bobbin;
A shaft rotatably provided on the central axis of the stator;
A rotor that rotates with the shaft according to a rotating magnetic field that is provided on the shaft and is generated by a current flowing through the motor coil;
A holder that is fixed so as to surround the shaft on one side surface of the stator and has a plurality of grooves extending in the circumferential direction;
A terminal for each phase of the motor coil provided in each groove;
A nut provided on the side opposite to the stator of the holder and screwed, a bus bar connected to a power supply line, and a bus bar side terminal connected by the screw, from the terminal along the axial direction of the shaft And a base that protrudes through and connects to the bus bar side terminal,
In a brushless motor for an electric power steering device that assists a steering force of a handle through the shaft connected to a steering mechanism of a vehicle,
The base is formed with a ring-shaped base partition wall that surrounds the shaft and has one end surface in contact with the inner wall surface of the housing and the other end surface in contact with the holder.
The base partition prevents the foreign matter from entering the air gap between the stator and the rotor through the gap between the holder and the housing. motor. A housing;
A bottomed cylindrical frame with a peripheral edge fixed to the housing;
A stator having a motor coil fixed to an inner wall surface of the frame and provided in a core and a slot of the core via a bobbin;
A shaft rotatably provided on the central axis of the stator;
A rotor that rotates with the shaft according to a rotating magnetic field that is provided on the shaft and is generated by a current flowing through the motor coil;
A holder that is fixed so as to surround the shaft on one side surface of the stator and has a plurality of grooves extending in the circumferential direction;
A terminal for each phase of the motor coil provided in each groove;
A nut provided on the side opposite to the stator of the holder and screwed, a bus bar connected to a power supply line, and a bus bar side terminal connected by the screw, from the terminal along the axial direction of the shaft And a base that protrudes through and connects to the bus bar side terminal,
In a brushless motor for an electric power steering device that assists a steering force of a handle through the shaft connected to a steering mechanism of a vehicle,
The base surrounds the shaft, and has a base partition wall whose end surface is in contact with the inner wall surface of the housing, and a cover wall that covers one side of the holder and whose end surface is in contact with the inner wall surface of the housing. And
The electric motor characterized in that the base partition wall and the covering wall prevent foreign matter from entering the air gap between the stator and the rotor through the gap between the holder and the housing. Brushless motor for power steering device. A housing;
A bottomed cylindrical frame with a peripheral edge fixed to the housing;
A stator having a motor coil fixed to an inner wall surface of the frame and provided in a core and a slot of the core via a bobbin;
A shaft rotatably provided on the central axis of the stator;
A rotor that rotates with the shaft according to a rotating magnetic field that is provided on the shaft and is generated by a current flowing through the motor coil;
A holder that is fixed so as to surround the shaft on one side surface of the stator and has a plurality of grooves extending in the circumferential direction;
A terminal for each phase of the motor coil provided in each groove;
A nut provided on the side opposite to the stator of the holder and screwed, a bus bar connected to a power supply line, and a bus bar side terminal connected by the screw, from the terminal along the axial direction of the shaft And a base that protrudes through and connects to the bus bar side terminal,
In a brushless motor for an electric power steering device that assists a steering force of a handle through the shaft connected to a steering mechanism of a vehicle,
The bobbin protrudes from both end surfaces of the core, and the tip of one ring-shaped flange extends and contacts the holder, and the tip of the other ring-shaped flange is in contact with the frame. Extending toward the inner wall of the bottom
A brushless motor for an electric power steering apparatus, wherein the flange prevents the foreign matter from entering the air gap between the stator and the rotor from the outer diameter side to the inner diameter side of the flange. The bobbin protrudes from both end surfaces of the core, and the tip of one ring-shaped flange extends and contacts the holder, and the tip of the other ring-shaped flange is in contact with the frame. Extending toward the inner wall of the bottom
5. The foreign material is prevented from entering the air gap between the stator and the rotor from the outer diameter side of the flange through the inner diameter side by the flange. A brushless motor for an electric power steering apparatus according to claim 1.

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