JP2007325348A - Rotating electric machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve the weight reduction and the space saving of a rotating electric machine and also to improve noise. <P>SOLUTION: This rotating electric machine is equipped with a rotor 16 which is fixed to a rotating shaft 14, a stator 18 which is arranged so as to oppose the rotor 16, a yoke 12 which is shaped like a bottomed cylinder and houses the rotor 16 and the stator 18 and axially supports the rotating shaft 14 rotatably, and a flange 20 which blocks an opening of the yoke 12. A plurality of mounts 28 projected along the rotating shaft 14 are formed at the opposite face to the stator 18 out of the flange 20, and the open side of the yoke 12 is press-fitted onto the peripheral side of each mount 28, and the open side of the yoke 12 is fastened to each mount 28 with screws 34. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a rotating electrical machine, and in particular, reduces the weight of an EPS motor that includes a rotor and a stator, and a yoke that rotatably supports the rotating shaft of the rotor and a flange that closes the opening side of the yoke. This relates to space saving and noise reduction.

Various motors such as EPS motors used in electric power steering devices have been proposed as rotating electric machines. When configuring an EPS motor, for example, in order to reduce the number of parts, instead of using a cylindrical frame and two brackets that respectively close both ends of the frame as a container for housing a rotor and a stator, A frame using a bottomed cylindrical frame (yoke) and a bracket (flange) that closes the opening side of the frame has been proposed (see Patent Document 1).
JP 2002-354755 A

  EPS motors are required to increase rigidity such as mounting rigidity and vibration rigidity as output increases. However, simply adopting the structure of a conventional EPS motor increases the weight to increase rigidity. It is feared that. That is, in a structure in which an annular attachment portion is formed on the opening side of a bottomed cylindrical frame (yoke) and the attachment portion and the bracket (flange) are fastened with bolts, the bottomed cylindrical frame is attached to the bracket ( In order to fix to the flange), an annular mounting portion must be formed on the frame, which increases the weight accordingly. When the ESP motor is used as an element of the steering system, if the weight of the EPS motor increases, the weight of the steering system increases and the outer diameter increases, which is not preferable in terms of in-vehicle layout.

  Further, when the weight of the EPS motor increases, there is a possibility that vibrations caused by mechanical or electrical excitation of the EPS motor or noises due to the natural vibration of the yoke or stator of the EPS motor itself may occur.

  The present invention has been made in view of the above-mentioned problems of the prior art, and an object thereof is to reduce the weight of the rotating electrical machine, save space, and improve noise.

  In order to achieve the above object, the present invention provides a rotor fixed to a rotating shaft, a stator disposed opposite to the rotor, and a bottomed cylindrical shape that houses the rotor and the stator. And a yoke that rotatably supports the rotating shaft of the rotor, and a flange that closes the opening of the yoke, and is mounted on the surface of the flange facing the stator along the rotating shaft. A rotating electric machine is configured in which a portion is formed and the opening side of the yoke is fixed to the mounting portion.

  According to the present invention, since the yoke and the flange are fixed via the mounting portion formed on the surface of the flange facing the stator, the entire rotating electrical machine is formed rather than when the mounting portion is formed on the opening side of the yoke. The increase in the weight of the motor can be suppressed, and the mounting rigidity can be increased by that amount, and the rigidity against vibration caused by the yoke and stator can be increased. It is possible to contribute to the improvement of

  According to the present invention, it is possible to reduce the weight of a rotating electrical machine, save space, and improve noise.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view of an EPS motor showing an embodiment of the present invention, and FIG. 2 is an enlarged sectional view of a main part of the EPS motor. 1 and 2, the EPS motor 10 includes a bottomed cylindrical yoke 12 as a rotating electric machine. In the yoke 12, a rotor 16 fixed to a rotating shaft 14 and a yoke inner wall surface are fixed. The stators 18 are housed opposite to each other. A flange 20 formed in a substantially disk shape is disposed on the opening side of the yoke 12. One end side of the rotating shaft 14 protrudes from a through hole 22 formed in a substantially central portion of the flange 20, and one end side of the rotating shaft 14 is rotatably supported by a bearing 24 fixed to the flange 20, and rotates. The other end side of the shaft 14 is rotatably supported by a bearing 26 fixed to the bottom of the yoke 12.

  A plurality of mounting portions 28 protruding along the rotation shaft 14 are formed on the surface of the flange 20 facing the stator 18 along the circumferential direction. The yoke 12 is fixed to the flange 20 by press-fitting or crimping the opening-side tip of the yoke 12 on the outer peripheral side of each mounting portion 28. Here, in order to more firmly fix the yoke 12 to the flange 20, each attachment portion 28 in the present embodiment has a screw hole 30 formed along the radial direction of the flange 20, and each screw hole. Corresponding to 30, a through hole 32 is formed in the yoke 12. A screw 34 as a fastening member is inserted into each through hole 32, and the opening side tip of the yoke 12 is firmly fixed to each mounting portion 28 by fastening the screw 34 and the screw hole 30. Instead of the screw 34, a rivet can be used as a fastening member.

  Each mounting portion 28 formed on the surface of the flange 20 facing the stator 18 is positioned with respect to the harness phase and the mounting phase with the steering column. Further, the structure in which the yoke 12 is fixed to each attachment portion 28 via the screw 34 functions as a rotation prevention structure for the yoke 12. Further, when forming a plurality of attachment portions 28 on the flange 20, the attachment portions 28 are formed in an annular shape along the circumferential direction at odd intervals, or the attachment portions 28 are circumferentially arranged at even intervals. It can be formed annularly along the direction.

  According to this embodiment, even when the weight of the EPS motor 10 is the same as that of the conventional EPS motor, it is not necessary to form an annular mounting portion on the opening side of the yoke 12 as compared with the conventional EPS motor. The mounting rigidity can be increased by the weight, and the rigidity against vibration caused by the yoke 12 and the stator 18 can be increased. On the other hand, even when the conventional EPS motor has the same rigidity against vibration of the EPS motor 10, it is not necessary to form an annular mounting portion on the opening side of the yoke 12, so that the weight can be reduced.

  Further, according to the present embodiment, when the yoke 12 is fixed to the flange 20, the opening side tip portion of the yoke 12 is press-fitted or fixed to the outer peripheral side of each mounting portion 28, and the screw 34 is inserted into the screw hole 30. Since the end of the opening side of the yoke 12 is firmly fixed to each mounting portion 28 by fastening, vibration caused by the yoke 12 and the stator 18, for example, as shown below, Natural vibration can be effectively suppressed.

  As the vibration inherent to the motor, for example, as shown in FIGS. 3A to 3C, an annular secondary natural vibration mode appears as vibration of the outer shape of the EPS motor 10. Specifically, when there is no vibration, the EPS motor (stator and yoke) 10 has an outer contour as shown by a dotted line. However, in the secondary natural vibration mode of the annular ring, the EPS motor 10 is shown in FIG. As shown in Fig. 3 (c), the top and bottom of the outer contour contract in the radial direction, and the left and right of the outer contour contract in the radial direction. The expansion mode is repeated alternately and continuously. As a result, by repeating the vibration in the circular secondary natural vibration mode, as shown in FIG. 3A, the outer contour of the EPS motor 10 has a vibration node (vibration amplitude minimum portion) 10a, A vibration antinode (vibration amplitude maximum portion) 10b is generated.

It is a longitudinal cross-sectional view of the EPS motor which shows one Example of this invention. It is a principal part expanded sectional view of an EPS motor. (A)-(c) is a conceptual diagram for demonstrating an annular secondary vibration mode.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 EPS motor 12 Yoke 14 Rotating shaft 16 Rotor 18 Stator 20 Flange 22 Through-hole 24, 26 Bearing 28 Mounting part 30 Screw hole 32 Through-hole 34 Screw

Claims (6)

  A rotor fixed to a rotating shaft, a stator disposed opposite to the rotor, and a bottomed cylindrical shape that houses the rotor and the stator, and rotatably supports the rotating shaft of the rotor. And a flange that closes the opening of the yoke. A mounting portion that protrudes along the rotation axis is formed on a surface of the flange facing the stator, and the mounting portion includes a yoke. A rotating electrical machine in which the opening side is fixed.   The rotating electrical machine according to claim 1, wherein the opening side of the yoke is press-fitted or crimped to the mounting portion.   The rotating electrical machine according to claim 1, wherein the opening side of the yoke and the attachment portion are fixed via a fastening member.   The said attachment part to which the opening part side of the said yoke was fixed functions as positioning with respect to the attachment phase with a harness phase or a steering core, or a rotation stop with respect to the said yoke, The Claim 1, 2, or 3 characterized by the above-mentioned. The rotary electric machine of any one of these.   5. The rotating electrical machine according to claim 1, wherein an odd number of the mounting portions are annularly formed on the flange at equal intervals.   5. The rotating electrical machine according to claim 1, wherein an even number of the mounting portions are annularly formed on the flange at irregular intervals.

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