JP2007221978A - Brushless motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a brushless motor which can effectively restrict motion in the thrust direction of a bearing fixed to each end of a rotating shaft by a simple constitution. <P>SOLUTION: This brushless motor has a stator 1 and a rotor 5 fixed to a rotating shaft 10 in a housing 11 where a flange 12 is fixed to its open end, and the stator 1 is provided with a plurality of salient magnetic poles 2a which are arrayed at equal intervals on the internal perimetric side of a core 2 of an armature, and also equipped with an armature coil 3 wound on each salient magnetic pole 2a, and the rotor 5 is equipped with a flanged permanent magnet field yoke 36 and a permanent magnet 37 for a cylindrical field. Bearings 16 and 17 which are fixed severally to each end of the rotating shaft 10 are retained by the bearing boxes 11a and 12a of the housing 11 and the flange 12. A coil spring 42 which presses each bearing 16 and 17 to the side of the bearing boxes 11a and 12a is arranged on the rotating shaft 10. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a brushless motor, and more particularly, to a permanent magnet field-type brushless motor suitable for use in vehicle auxiliary equipment.

  In recent years, in order to reduce the fuel consumption of vehicles, vehicle auxiliary machines such as oil pumps that have been driven by an engine tend to be electrified. As a motor for driving these auxiliary machines, a permanent magnet field type brushless motor having a long life and a low failure rate has been used.

  As shown in FIG. 5, a conventional permanent magnet field brushless motor has a stator 1 and a rotor 5 fixed to a rotary shaft 10 in a housing 11 made of steel or the like, and a housing 11 on the output shaft side. A flange 12 that also serves as a cover made of aluminum alloy or the like is attached and fixed to the opening end side of the plate.

  The stator 1 is provided with a plurality of salient poles 2a for three phases arranged at equal intervals on the inner peripheral surface side of the armature core 2, and an insulator-made reel 4 disposed on each of the salient poles 2a. In addition, armature windings 3 that are connected in three phases are wound. A cable 13 is connected to the end of the armature winding 3 of each phase and pulled out of the housing 11, and a terminal 14 at the tip of the cable 13 is held by a connector housing 15 made of an insulator.

  Further, the rotor 5 includes a plurality of magnetic pole permanent magnets 7 arranged on the outer peripheral surface of a cylindrical permanent magnet field yoke 6 fixed to the rotating shaft 10 by mechanical means or the like, and an adhesive layer 8 of a heat resistant adhesive. The magnet cover 9 is provided so as to be fixed and to cover the magnetic pole permanent magnet 7 portion.

  Normally, in a permanent magnet field-type brushless motor, the current flowing through the armature winding 3 is determined by magnetic pole position information which is rotation angle information of the N pole and S pole of the magnetic pole permanent magnet 7 detected by the magnetic detection element 20. I have control. For this reason, a yoke and plate 18 that rotates in synchronization with the magnetic pole permanent magnet 7 is fixed to the rotary shaft 10, and a magnetic pole position detection permanent magnet 19 is held on the rotary shaft 10 to use the magnetic pole position information for acquisition. Indirect detection is performed by a magnetic detection element 20 such as a Hall element used as a position sensor.

  The magnetic detection element 20 is usually mounted on a printed circuit board 21 that is fixed to the flange 12 side, and is disposed opposite the magnetic pole position detection permanent magnet 19 with a predetermined interval. Further, the terminals of the magnetic detection element 20 are connected to the detection cable 22 through a conductor pattern formed in the printed circuit board 21, and are pulled out to the connector housing 15 outside the housing 11 like the cable 13. Yes. As is well known, the power of the magnetic detection element 20 is supplied from the outside of the motor through the detection cable 22 in the same manner as the current of the armature winding 3. The magnetic pole position signal detected by the magnetic detection element 20 is sent to the controller from the detection cable 22 drawn out of the motor.

  The magnetic pole of the magnetic pole position detecting permanent magnet 19 is magnetized so that the surface facing the magnetic detecting element 20 has the same relationship as the outer peripheral pole of the magnetic pole permanent magnet 7, that is, the angular position of the N and S poles. In addition, the permanent magnet 19 for detecting the magnetic pole position is fixed so that the current flowing in the armature winding 3 needs to be controlled with high accuracy, so that the deviation of the magnetic pole permanent magnet 7 from the magnetic pole position of the N-pole and S-pole angles. It is assembled to be as small as possible.

  On the other hand, the rotary shaft 6 provided with the stator 5 has bearings 16 and 17 fixed to the left and right by press-fitting or the like, respectively. , 12a are fitted and supported. Since the bearings 16 and 17 are fitted with a gap due to a difference in linear expansion with the bearing housings 11a and 12a due to a temperature rise during operation of the motor, for example, a C-shaped stopper that holds the side surface of the bearing 17 on the bearing housing 12a side in FIG. Wheels 22 and leaf springs are provided to restrict the movement in the thrust direction due to vibration during operation.

  The structure of the brushless motor and the mounting structure of the magnetic detection element as described above are described in, for example, Patent Documents 1 to 3, and examples of means for restricting the movement of the bearing in the thrust direction are disclosed in Patent Document 4 and the like. Are listed.

Japanese Patent Laid-Open No. 2-87959 JP-A-6-113520 JP 2002-10777 A JP-A-5-64390

  In order to restrict the thrust movement of the bearing based on vibration during operation with a conventional brushless motor, the configuration in which the C-shaped retaining ring 22 and the leaf spring are provided in the bearing portion increases the number of components and the structure is complicated. There is a problem.

  The C-shaped cover 22 that holds the outer ring of the bearing 17 on the output shaft side is generally made of an aluminum alloy because of the degree of freedom of shape. When the temperature is high, the fitting becomes a gap, and the outer ring portion of the bearing 17 rotates, which may cause wear of the bearing box 12a on the C-shaped cover 22 side. For this reason, various proposals for suppressing the movement of the bearings 16 and 17 have been made, but there is not enough, and this improvement has been desired.

  An object of the present invention is to provide a brushless motor capable of effectively regulating the movement in the thrust direction of a bearing fixed to each end of a rotating shaft with a simple configuration.

  In the brushless motor of the present invention, a housing having a flange fixed to an opening end has a stator and a rotor fixed to a rotating shaft, and the stator is arranged at equal intervals on the inner peripheral surface side of the armature core. A plurality of salient poles, and armature windings wound around each of the salient poles, wherein the rotor comprises a permanent magnet field yoke and a permanent magnet for the pole, and the end of the rotating shaft The bearing fixed to each part is held by a bearing box of a housing and a flange, and the rotary shaft is configured by arranging a coil spring that presses each bearing toward the bearing box. .

  Preferably, a small-diameter portion smaller than a portion to which the cylindrical permanent magnet field yoke is fixed is provided on a part of the rotating shaft, and a coil spring that presses the bearings toward the bearing box is disposed in the small-diameter portion. It is characterized by comprising.

  If configured as in the present invention, the coil springs arranged on the rotating shaft part always apply a pressing force to the bearings on the bearing box side, so that the fitting part is loosened due to a temperature rise during operation of the motor. Even if it occurs, the movement in the thrust direction of the bearing based on the vibration during operation can be effectively regulated, and a highly reliable motor can be obtained.

  A brushless motor of the present invention has a stator and a rotor fixed to a rotating shaft in a housing that fixes a flange to an opening end, and the stator is arranged at equal intervals on the inner peripheral surface side of the armature core. A plurality of salient poles, and armature windings wound around each of the salient poles, wherein the rotor comprises a permanent magnet field yoke and a permanent magnet for the pole, and the end of the rotating shaft The bearings fixed to the respective parts are held by the housing box of the housing and the flange. A coil spring that presses the bearings toward the bearing housing is arranged on the rotating shaft.

  An embodiment of the brushless motor of the present invention will be described below with reference to the drawings in which the same parts as those in the prior art are denoted by the same reference numerals. As shown in FIG. 1, the rotor 5 of the present invention is for a cylindrical field which forms a plurality of magnetic poles for each phase on a brazed permanent magnet field yoke 36 fitted and fixed to a rotary shaft 10 as will be described later. The permanent magnet 37 is fixed to constitute a permanent magnet field.

  Then, on one end face of the cylindrical field permanent magnet 37, the magnetic detection element 20 is arranged at a position facing it through a small gap, and the magnetic pole position which is the rotation angle information of the N pole and S pole of each phase Information is detected and the current flowing through the armature winding 3 is controlled.

  The magnetic detection element 20 is connected to an internal wiring by fixing each phase component at a predetermined position on the printed circuit board 21. For example, the printed circuit board 21 is formed in a disk shape through which the rotary shaft 10 can pass, and has a cylindrical boundary. The magnetic detection elements 20 for three phases can be easily arranged to face each other at one end face position of the permanent magnet 37 for magnetism. In this structure, not only can the axial dimension of the motor be shortened but also the number of parts can be reduced, so that the motor can be lightweight and easy to assemble.

  As shown in FIG. 1, the printed circuit board 21 is mechanically supported by an insulator holder 22 disposed and held between the housing 11 and the flange 12, and is previously opposed to one end face of the cylindrical field permanent magnet 37. Magnetic detecting elements 20 for three phases are arranged at predetermined predetermined positions.

  The insulator holder 22 is made of a heat-resistant resin in a circular shape that can be placed and fixed between the housing 11 and the flange 12, for example, and is provided with a projection 23 for mechanically supporting the printed board 21 at a predetermined position. ing. The insulator holder 22 is electrically connected with a bus bar 33 for three phases from a plurality of terminals 32 connected to the lead wire 3 a of the armature winding 3 and a plurality of detection bus bars 34 connected to the magnetic detection element 20. It is built in an insulated state. The externally exposed portion of the detection bus bar 34 is penetrated at the connection position of the printed circuit board 21 and is electrically connected to the internal wiring pattern with solder or the like so that the connection wiring is not routed.

  The insulator holder 22 has three bus bars 33 for three phases and three output signal bars for the magnetic detection element 20 and five detection bus bars 34 for positive and negative electrodes. An integrated connector housing 35 is formed around the portion 44 so as to facilitate connection to the outside.

  In the brushless motor according to the embodiment of the present invention, as shown in FIGS. 1 to 3, the rotor 5 uses a cylindrical brazed permanent magnet field yoke 36 in which, for example, a disk-shaped flange 38 is formed on one end side. The brazed permanent magnet field yoke 36 is fixed to the rotary shaft 10.

  The hollow permanent magnet field yoke 36 is fitted with a hollow cylindrical field permanent magnet 37 to be inserted from one end side to the flange portion 38 side and fixed integrally with the adhesive layer 8. For example, the adhesive layer 8 is fixed between the two by applying an adhesive to the outer peripheral surface of the brazed permanent magnet field yoke 36 and then fitting the cylindrical field permanent magnet 37 to cure the adhesive. Alternatively, it may be performed by injecting an adhesive into the gap between the two after the fitting and curing the adhesive.

  In addition, in this embodiment, the rotor 5 is integrated by covering from the flange 38 side of the permanent magnet field yoke 6 with a cup-shaped magnetic pole cover 42 used for protecting the outer surface of the cylindrical field permanent magnet 37. It has a configuration. For example, the cup-shaped magnetic pole cover 42 is fitted and fixed to the rotary shaft 10 or is fixed by fitting a cylindrical field permanent magnet 37 whose outer surface is coated with an adhesive.

  The flange portion 38 of the flanged permanent magnet field yoke 36 is formed concentrically with the rotating shaft 10 and has the same size as the outer diameter of the cylindrical field permanent magnet 37 for easy assembly. The permanent magnet 37 can be used as a seat when the permanent magnet 37 is inserted. If the opposing arrangement of the magnetic detection element 20 and a bearing portion to be described later are taken into consideration, a permanent magnet for a cylindrical field can be used.

  The cup-shaped magnetic pole cover 42 has a through hole 39 through which the rotary shaft 10 is passed using a non-magnetic material such as stainless steel. The inner diameter dimension of the cup-shaped magnetic pole cover 42 is smaller than the outer diameter dimension of the cylindrical field permanent magnet 37. A minimum gap that can be assembled is formed. If this cup-shaped magnetic pole cover 42 is used, it is possible to prevent the cylindrical magnetic field permanent magnet 37 from being damaged during the rotation of the rotor 5, and to prevent the cup-shaped magnetic pole cover 42 from being bonded to the adhesive layer 8. If the magnet is incorporated in a state where the permanent magnet is not hardened, the misalignment between the permanent magnet field yoke 36 and the cylindrical field permanent magnet 37 can be suppressed physically.

  If the cylindrical field permanent magnet 37 is used and the outer diameter and the dimension of the flange portion 38 of the flanged permanent magnet field yoke 36 and the inner diameter of the cup-shaped magnetic pole cover 42 are appropriately selected, the cylindrical field magnet is selected. The mechanical misalignment of the permanent magnet 37 and the brazed permanent magnet field yoke 36 can be mechanically suppressed, the non-uniformity of the adhesive layer 8 can be made smaller, the torque fluctuation is small, and the brushless motor can be made with low vibration and low noise.

  In this example, the size of the cylindrical field permanent magnet 37 is set such that the end facing the magnetic detection element 20 protrudes beyond the end surface of the brazed permanent magnet field yoke 36, thereby The end face of the magnet permanent magnet 37 and the magnetic detection element 20 are opposed to each other at a smaller interval.

  The adhesive layer 8 with a narrow gap between the permanent magnet field yoke 6 and the cylindrical field permanent magnet 37 is used to make the fixing of the brazed permanent magnet field yoke 36 as shown in FIG. A plurality of linear grooves 40 substantially parallel to the axial direction are provided on the outer peripheral surface, the adhesive layer 8 is partially thickened by the linear grooves 40, and the circumferential groove 41 is provided in the vicinity of the flange 38 side. Similarly, the adhesive layer 8 is partially thickened.

  These linear grooves 40 and circumferential grooves 41 are provided either or both at the same time depending on the size of the permanent magnet field yoke 36 and the cylindrical field permanent magnet 37, and the number and size thereof. The height can be changed. As a result, the adhesive layer 8 can be partially thickened by the grooves 40 and 41, so that the permanent magnet field yoke 36 and the cylindrical field permanent magnet 37 by the adhesive layer 8 are more securely fixed and bonded. The peeling of the layer 8 can be effectively prevented, and the stability of the shear strength can be increased to improve the reliability.

  The rotating shaft 10 having the rotor 5 is supported by bearings 16 and 17 fitted to the bearing boxes 11a and 12a. According to the present invention, as shown in FIGS. A spring 45 is arranged, and the bearings 16 and 17 are pressed toward the bearing housings 11a and 12a by the pressing force of the coil spring 45, thereby restricting the movement of the bearings in the thrust direction.

  The rotary shaft 10 of the embodiment shown in the figure is provided with a small diameter portion having a smaller diameter D2 in the output shaft side portion than the diameter D1 of the shaft to which the brazed permanent magnet field yoke 36 is fixed. A coil spring 45 is disposed. In addition, one end of the coil spring 45 in the example of FIG. 3 is engaged with the rotary shaft 10 via a spring seat 46 and the other end is engaged with the side surface of the bearing 17 via a spring seat 47. It is combined. Thus, the bearings 16 and 17 can be pressed against the bearing housings 11a and 12a by the pressing force of the coil spring 45 without affecting the rotor 5.

  If the both ends of the coil spring 45 are shaped flat, the side surface of the permanent magnet field yoke 6 of the rotor 5 can be provided even when the spring seats 46 and 47 are omitted when the coil spring 45 is arranged on the rotary shaft 10. And the risk of damaging the side surfaces of the bearing 17 can be eliminated.

  When the coil spring 45 is arranged on the rotary shaft 10 in this manner, the inner ring portion of the bearings 16 and 17 is caused by the force of the coil spring 45 applied during assembly for fixing the flange to the housing 11 as shown in FIG. Since the outer ring portion is always pressed from the side surface, the outer ring portion is pressed toward the outer side and the outer circumferential direction by the rotating ball.

  Therefore, even if the bearings 16 and 17 are loosened between the bearing boxes 11a and 12a to be fitted and fixed, the pressing force of the coil spring 45 becomes a frictional force to limit the rotation of the bearing outer ring, The axial movement of the rotor 5 due to vibration during motor operation can be effectively restricted.

  In the embodiment of the present invention shown in the figure, since the coil spring 45 is arranged using the space of the rotary shaft 10 portion on the side where the magnetic detection element 20 is arranged, the axial dimension of the motor is increased. It can be produced without.

  The position where the coil spring 45 is arranged can be changed depending on the structure of the rotor 5, the shape of the housing 11, and the like. Can be added.

It is a longitudinal cross-sectional view which shows one Example of the brushless motor of this invention. It is a disassembled perspective view of a rotor. It is explanatory drawing which carried out some longitudinal cross sections of the rotor. It is explanatory drawing of a bearing part. It is a longitudinal cross-sectional view of the conventional brushless motor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Stator, 2 ... Armature core, 2a ... Salient pole magnetic pole, 3 ... Armature winding, 5 ... Rotor, 8 ... Adhesive layer, 10 ... Rotating shaft, 11 ... Housing, 12 ... Flange, 11a, 12a DESCRIPTION OF SYMBOLS ... Bearing housing, 16, 17 ... Bearing, 20 ... Magnetic detection element, 36 ... Permanent permanent magnet field yoke, 37 ... Cylindrical field permanent magnet, 38 ... Saddle, 42 ... Cup-shaped magnetic pole cover, 45 ... Coil spring.

Claims (2)

  A housing that fixes a flange to an open end has a stator and a rotor that is fixed to a rotating shaft, and the stator has a plurality of salient poles arranged at equal intervals on the inner peripheral surface side of the armature core. An armature winding wound around each of the salient pole magnetic poles, the rotor including a permanent magnet field yoke and a permanent magnet for magnetic poles, and bearings that are respectively fixed to the ends of the rotary shaft. In the brushless motor held by the housing box of the housing and the flange, the brushless motor is characterized in that a coil spring that presses the bearings toward the bearing box is arranged on the rotating shaft. 2. The coil spring according to claim 1, wherein a small-diameter portion smaller than a portion to which the cylindrical permanent magnet field yoke is fixed is provided on a part of the rotating shaft, and a coil spring that presses the bearings toward the bearing box is disposed in the small-diameter portion. A brushless motor characterized by being configured as described above.

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