JP5087443B2 - Brushless motor - Google Patents

Description

The present invention relates to a brushless motor.

In recent years, in manufacturing a motor, a bracket to which components are attached is sometimes made of a resin material in order to reduce weight and integrate functions (see, for example, Patent Document 1). Constructing the bracket with a resin material is an effective means in that various terminals can be molded with resin.
International Publication No. 2005/090968 Pamphlet

However, when the bracket is formed of a resin material as in Patent Document 1, it is difficult to ensure the accuracy in a portion where high dimensional accuracy is required, such as an inlay portion that is a joint portion with another member (metal material). . Therefore, the bracket manufactured by injection molding or the like is subjected to additional processing such as cutting to ensure the accuracy of the product. However, the bracket may be deformed by heat generated during cutting.
In addition, when a motor having a bracket made of a resin material is used at a location where the temperature change is large in an environment where the motor is used, such as an electric power steering, the bracket made of a resin material at a joint with another member made of a metal material However, there is a concern that stress concentration occurs due to repeated expansion and contraction, and cracks occur in the bracket. This is because such a phenomenon occurs because the thermal expansion coefficient of the resin material is larger than the thermal expansion coefficient of the metal material.

Accordingly, the present invention has been made in view of the above circumstances, and a brushless motor including a resin bracket that can be reliably bonded to other members and can suppress the occurrence of cracks. It is to provide.

In order to solve the above problems, the invention described in claim 1 is a motor case, a stator fixed to the motor case, a rotor provided rotatably with respect to the stator, and rotation of the rotor. A motor case formed on the bracket in a brushless motor comprising: a sensor unit for detecting an angle; and a bracket made of a resin material that closes an opening of the motor case and rotatably supports the rotor. And the fitting inlay part with the sensor unit holder that accommodates the sensor unit are formed in an annular shape around the axis of the rotor, and are formed on the outer peripheral surface of each fitting inlay part. are ribs respectively formed on the outer circumferential surface of the fitting socket portion of the motor casing, the motor so as to abut on the rib The case is externally fitted, and the sensor unit holder is externally fitted on the outer peripheral surface of the fitting inlay portion with the sensor unit holder so as to contact the rib, and the motor case and the sensor unit Each of the holders is attached from the rotor side of the bracket, and is fixed by a fastening member screwed from the rotor side .

By comprising in this way, in the joining location of a bracket and a motor case, it joins so that the rib of a bracket may contact with a motor case. Therefore, since it is not necessary to contact portions other than the ribs of the fitting spigot portion with the motor case, the dimensional accuracy of the fitting spigot portion can be relaxed. That is, if the dimensional accuracy of the rib of the fitting inlay part is ensured, it can be reliably joined to the motor case.
Further, the bracket rib and the sensor unit holder are joined so that the rib of the bracket is in contact with the sensor unit holder. Therefore, since it is not necessary to make the portions other than the ribs of the fitting spigot part contact with the sensor unit holder, the dimensional accuracy of the fitting spigot part can be relaxed. That is, if the dimensional accuracy of the rib of the fitting inlay part is ensured, it can be reliably joined to the sensor unit holder.
Moreover, in order to improve the dimensional accuracy of the fitting spigot part, it is only necessary to cut only the ribs when performing the cutting process, and it is not necessary to cut the entire circumference. Therefore, the heat generated during the cutting process can be minimized and the deformation of the bracket can be suppressed.
Furthermore, when a motor is used in a place where the temperature change is large, by forming a rib in the fitting inlay part, a thick part (rib forming part) and a thin part are formed, and the thin part is thin. Stress can be relieved at the part to absorb heat deformation (expansion and shrinkage). Moreover, since the contact area of a fitting inlay part and the other party member becomes small, the influence of the heat from the other party member can be made small. Therefore, it can suppress that a crack generate | occur | produces in a bracket.

The invention described in claim 2 is characterized in that a plurality of the ribs are formed at substantially equal intervals along the circumferential direction.
With this configuration, when the fitting inlay portion expands and contracts due to a change in temperature environment, the fitting inlay portion expands and contracts substantially evenly because the ribs are formed at substantially equal intervals in the circumferential direction. . Therefore, when the motor is driven, it is possible to suppress the occurrence of rattling at the joint portion between the bracket and the counterpart member, and it is possible to suppress noise when the motor is driven.

According to the present invention , the bracket rib and the motor case are joined so that the rib of the bracket is in contact with the motor case. Therefore, since it is not necessary to contact portions other than the ribs of the fitting spigot portion with the motor case, the dimensional accuracy of the fitting spigot portion can be relaxed. That is, if the dimensional accuracy of the rib of the fitting inlay part is ensured, it can be reliably joined to the motor case.
Further, the bracket rib and the sensor unit holder are joined so that the rib of the bracket is in contact with the sensor unit holder. Therefore, since it is not necessary to make the portions other than the ribs of the fitting spigot portion contact the sensor unit holder, the dimensional accuracy of the fitting spigot portion can be relaxed. That is, if the dimensional accuracy of the rib of the fitting inlay part is ensured, it can be reliably joined to the sensor unit holder.
Moreover, in order to improve the dimensional accuracy of the fitting spigot part, it is only necessary to cut only the ribs when performing the cutting process, and it is not necessary to cut the entire circumference. Therefore, the heat generated during the cutting process can be minimized and the deformation of the bracket can be suppressed.
Furthermore, when a motor is used in a place where the temperature change is large, by forming a rib in the fitting inlay part, a thick part (rib forming part) and a thin part are formed, and the thin part is thin. Stress can be relieved at the part to absorb heat deformation (expansion and shrinkage). Moreover, since the contact area of a fitting inlay part and the other party member becomes small, the influence of the heat from the other party member can be made small. Therefore, it can suppress that a crack generate | occur | produces in a bracket.

Next, an embodiment of the present invention will be described with reference to FIGS. In the present embodiment, a brushless motor used for electric power steering of a vehicle will be described as an example.
(Brushless motor)
As shown in FIG. 1, the brushless motor 1 is used for, for example, electric power steering (EPS), and has a stator 3 fitted and fixed to a bottomed cylindrical motor case 2; The rotor 4 is provided so as to be rotatable with respect to the stator 3, and a bracket 6 for closing the rotor 6 is fastened and fixed to the opening 5 of the motor case 2 by a bolt 26. The motor case 2 is made of a metal material.

  A stator 3 is fitted and fixed to the peripheral wall 7 of the motor case 2. A boss portion 9 is formed in the end portion (bottom portion) 8 of the motor case 2 at the center in the radial direction, and a bearing 10 is press-fitted therein. A rotating shaft 11 of the rotor 4 is rotatably supported by the bearing 10.

  The stator 3 has a substantially cylindrical stator core 12. The stator core 12 is formed by laminating a plurality of metal plates (electromagnetic steel plates) 13 punched in a substantially ring shape by pressing in the axial direction of the rotor 4, and a plurality of teeth portions 15 for winding the coils 14 are radially arranged. Is formed. Each tooth portion 15 is provided with an insulator 16 that is an insulating material over the entire circumference, and a coil 14 is wound on the insulator 16.

  A terminal unit 22 having a plurality of terminals 21 is provided on the side of the stator 3 opposite to the end portion 8. The terminal unit 22 has a role of electrically connecting a stator winding 23 drawn from the coil 14 of the stator 3 and an external power source (not shown). Line 23 is connected.

  The rotor 4 is provided with a permanent magnet 17 at a portion corresponding to the stator 3 of the rotating shaft 11, and a resolver rotor 19 constituting a resolver 18 for detecting the rotation angle of the rotating shaft 11 on the opposite side of the bearing 10 of the rotating shaft 11. It is provided. The permanent magnet 17 is magnetized so that the magnetic poles change in order in the circumferential direction.

  As shown in FIGS. 1 to 3, the bracket 6 is made of a resin and is formed in a substantially disk shape in plan view. The resin is preferably a polyphenylene sulfide (PPS) resin, which is a thermoplastic crystalline plastic. However, other resins may be used. On the motor case 2 side (lower side in FIG. 1) of the bracket 6, a cylindrical motor case spigot portion (fitting spigot portion) 28 that is fitted to the peripheral wall 7 of the motor case 2 is provided. On the other hand, on the side opposite to the motor case 2 of the bracket 6 (upper side in FIG. 1), a cylindrical speed reducer inlay portion (fitting inlay portion) 29 to be fitted to a speed reducer or the like is provided. An O-ring groove 30 for attaching an O-ring (not shown) is formed on the outer peripheral surface 29a of the speed reducer inlay portion 29 along the circumferential direction.

  As shown in FIG. 4, the speed reducer inlay portion 29 of the bracket 6 is formed in an annular shape. Further, ribs 80 are formed at substantially equal intervals in the circumferential direction on the motor case 2 side (upper side in FIG. 4) of the O-ring groove 30 on the outer circumferential surface 29a of the speed reducer inlay portion 29 (in this embodiment, 6 pieces every 60 °). The rib 80 is formed so as to protrude (convex) from the outer peripheral surface 29a.

  The motor case inlay portion 28 of the bracket 6 is also formed in an annular shape. In addition, ribs 85 are formed at substantially equal intervals in the circumferential direction on the contact surface of the outer peripheral surface 28a of the motor case inlay portion 28 with the motor case 2 (in this embodiment, six ribs are provided every 60 °). . The rib 85 is formed to protrude (convex) from the outer peripheral surface 28a.

  An insertion hole 31 for inserting the rotating shaft 11 of the rotor 4 is formed in the center of the bracket 6 in the radial direction (see FIG. 3), and a metal-made bottomed cylindrical bearing housing 32 is insert-molded therein. ing. The bearing housing 32 is disposed so that the end portion 32a is positioned on the reduction gear inlay portion 29 side. An insertion hole 33 for inserting the rotating shaft 11 of the rotor 4 is formed in the center in the radial direction of the end portion 32a. A bearing 34 is fitted and fixed to the peripheral wall 32 b of the bearing housing 32. The shaft 34 of the rotor 4 is rotatably supported by the bearing 34.

  A resolver stator 20 constituting a resolver (sensor unit) 18 is disposed at a position corresponding to the resolver rotor 19 on the opposite side of the bracket 6 from the bearing 34. A resolver holder 35 fixed to the bracket 6 is externally fitted to the resolver stator 20. The resolver holder 35 is made of metal and formed in a bottomed cylindrical shape.

  As shown in FIG. 5, a resolver inlay part (fitting inlay part) 81 is provided at a fitting part of the bracket 6 with the resolver holder 35. In the resolver stator 20, movement of the rotor 4 in the axial direction and the radial direction is restricted by the resolver holder 35. An insertion hole 36 for inserting the rotary shaft 11 of the rotor 4 is formed in the end portion 35 a of the resolver holder 35.

  Moreover, the resolver low part 81 of the bracket 6 is formed in an annular shape. Further, ribs 90 are formed at substantially equal intervals in the circumferential direction on the contact surface with the resolver holder 35 on the outer peripheral surface 81a of the resolver low part 81 (in this embodiment, six ribs are provided every 60 °). The rib 90 is formed so as to protrude (convex) from the outer peripheral surface 81a.

  The outer peripheral surface 6a of the bracket 6 is connected to an external control circuit (not shown) and is connected to an external power source (not shown) connected to an external power source (not shown) and a sensor connector 37 for taking out an electric signal from the resolver stator 20. The power connector 38 for supplying the power is integrally formed. The power connector 38 includes three plate-like power terminals 70.

  Each power terminal 70 is punched from a metal plate by pressing or the like, and is formed to extend to three terminals 21a, 21a, 21a (see FIG. 5) exposed from the terminal unit 22. . Each power terminal 70 is connected to the terminal 21a. As a result, power is supplied to the terminal unit 22 via the power connector 38.

  The outer peripheral surface 6a of the bracket 6 has two female screw portions 24 for fixing the motor case 2, and a bolt hole 25 for fixing the brushless motor 1 to a metal counterpart member 95 such as a speed reducer. Are provided in two places. A metal collar 27 is insert-molded in the bolt hole 25.

  Returning to FIG. 1, the resolver stator 20 has a substantially annular core configured by laminating plates 39 made of a magnetic material. The core is provided with a plurality of teeth 41 projecting radially inward at equal intervals. A coil 43 is wound around these teeth portions 41 after an insulator, which is an insulating material, is mounted.

  A notch 68 is formed in the peripheral wall 35b of the resolver holder 35 that fixes the resolver stator 20 to the bracket 6 at a portion corresponding to the terminal holding portion 45 of the insulator. The resolver stator 20 is configured such that the displacement of the resolver stator 20 in the rotation direction of the rotor 4 is restricted by fitting the terminal holding portion 45 into the notch portion 68 of the resolver holder 35.

  The winding of the coil 43 is wound so that three coils are formed on the plurality of tooth portions 41. The ends of the windings of the coils 43 are led out from the terminal holding portions 45 of the insulators to conductive terminals 46 protruding along the axial direction of the rotor 4 (vertical direction in FIG. 1).

  Six terminals 46 are provided corresponding to the number of winding ends of the coil 43, and the winding ends of the coil 43 are wound around the terminals 46, respectively. Each terminal 46 is integrally formed with a conductive harness connection terminal 47. The resolver stator 20 is coated with a resin so as to cover the harness connection terminal 47, the connection portion between the end of the coil 43 and the terminal 46, and the entire coil 43, and protects the connection portion and the winding.

  The harness connection terminal 47 is formed to have a substantially L-shaped cross section, and extends in the radial direction (left-right direction in FIG. 1). The proximal end side of the harness connection terminal 47 is provided with a terminal 46 around which the coil 43 is wound, and the distal end side is bent along the axial direction of the rotor 4.

  As shown in FIG. 2, the sensor connector 37 integrally formed on the outer peripheral surface 6 a of the bracket 6 can receive a signal cable (not shown) connected to an external control circuit at the outer end. A mouth 53 is formed. The receiving port 53 is provided with six sensor connection terminals 54 corresponding to the number of harness connection terminals 47 of the resolver stator 20.

  Each sensor connection terminal 54 is punched from a metal material by pressing or the like, and has a connection terminal main body 55 extending from the receiving port 53 of the sensor connector 37 to the harness connection terminal 47. These connection terminal bodies 55 are bent so as to correspond to the shapes of the sensor connector 37 and the bracket 6.

  At the end of the connection terminal main body 55 on the resolver stator 20 side, a tongue piece portion 61 having a width smaller than that of the connection terminal main body 55 is formed (see FIG. 1). The tongue piece portion 61 is formed in a substantially L-shaped cross section, and includes a vertical tongue piece portion 62 bent and extended from the connection terminal main body 55 along the axial direction (vertical direction in FIG. 1). A horizontal tongue piece portion 63 that is bent and extended from the tongue piece portion 62 along the horizontal direction (left and right direction in FIG. 1) is formed in series. In the tongue piece portion 61 formed in this way, the lateral tongue piece portion 63 is electrically connected to the tip of the harness connection terminal 47 of the resolver stator 20.

  As shown in FIG. 3, the sensor connection terminal 54 has a resin mold portion 65 that covers the connection terminal main body 55. The resin mold portion 65 is formed to have a substantially rectangular cross section, and is bent so as to correspond to the connection terminal main body 55 in a plan view. Thus, the connection terminal main body 55 of the sensor connection terminal 54 is insert-molded in the bracket 6 in a state of being covered with the resin mold portion 65.

Next, a method for fixing the bracket 6 (brushless motor 1) to a counterpart member 95 such as a speed reducer will be described.
As shown in FIG. 6, when the bracket 6 is attached to the counterpart member 95 such as a speed reducer, the bolt hole 25 formed in the bracket 6 is aligned with the screw hole 91 of the counterpart member 95. At this time, the inner peripheral surface 95 b of the concave portion 95 a of the counterpart member 95 is fitted so as to come into contact with the outer surface 29 a of the speed reducer inlay portion 29 of the bracket 6. Then, the inner peripheral surface 95 b of the counterpart member 95 comes into contact with the rib 80 formed on the outer surface 29 a of the reduction gear inlay portion 29. Then, the bolt 92 is inserted into the bolt hole 25 and screwed into the screw hole 91, so that the mating member 95 and the bracket 6 (brushless motor 1) are coupled.

Similarly, a method for fixing the bracket 6 and the motor case 2 will be described.
As shown in FIG. 7, when the bracket 6 and the motor case 2 are connected and fixed, the female screw hole 24 formed in the bracket 6 is aligned with the through hole 2 a of the motor case 2. At this time, the inner peripheral surface 2 b of the motor case 2 is fitted so as to come into contact with the outer surface 28 a of the motor case inlay portion 28 of the bracket 6. Then, the inner peripheral surface 2 b of the motor case 2 comes into contact with a rib 85 formed on the outer surface 28 a of the motor case inlay portion 28. Then, the bolt 26 is inserted into the through hole 2a and screwed into the female screw hole 24, so that the motor case 2 and the bracket 6 are coupled.

Further, a method for fixing the bracket 6 and the resolver holder 35 will be described.
As shown in FIG. 8, when the bracket 6 and the resolver holder 35 are connected and fixed, the female screw hole 75 formed in the bracket 6 is aligned with the through hole 35 c of the resolver holder 35. At this time, the inner peripheral surface 35 d of the resolver holder 35 is fitted so as to come into contact with the outer surface 81 a of the resolver inlay part 81 of the bracket 6. Then, the inner peripheral surface 35 d of the resolver holder 35 comes into contact with the rib 90 formed on the outer surface 81 a of the resolver low part 81. Then, the resolver holder 35 and the bracket 6 are joined by inserting the bolt 76 through the through hole 35 c and screwing it with the female screw hole 75.

According to the present embodiment, since the rib 80 is formed in the speed reducer inlay portion 29 of the bracket 6 made of a resin material with the counterpart member (reduction gear) 95, in the joint portion between the bracket 6 and the counterpart member 95, The ribs 80 of the bracket 6 are joined so as to contact the mating member 95. Accordingly, since it is not necessary to make contact with the counterpart member 95 except for the rib 80 of the speed reducer inlay part 29, the dimensional accuracy of the speed reducer inlay part 29 can be relaxed. That is, if the dimensional accuracy of the rib 80 of the speed reducer inlay portion 29 is ensured, the mating member 95 can be reliably joined.
Further, in order to increase the dimensional accuracy of the reducer inlay portion 29, it is only necessary to cut only the rib 80 when performing the cutting process, and it is not necessary to perform the cutting over the entire circumference. Therefore, heat generated during cutting can be minimized, and deformation of the bracket 6 during cutting can be suppressed.
Further, in the brushless motor 1 for electric power steering, the rib 80 is formed in the speed reducer inlay portion 29, so that a thick portion (rib forming portion) and a thin portion are formed, and the thin thickness is reduced. Stress can be relieved at the part to absorb heat deformation (expansion and shrinkage). Further, since the contact area between the speed reducer inlay portion 29 and the mating member 95 is reduced, the influence of heat from the mating member 95 can be reduced. Therefore, it is possible to suppress the occurrence of cracks in the bracket 6.

  Similarly, since the rib 85 is formed in the motor case inlay part 28 with the motor case in the bracket 6, substantially the same operation and effect as when the rib 80 of the reduction gear inlay part 29 described above is formed can be obtained.

  Furthermore, since the rib 90 is formed in the resolver inlay part 81 with the resolver holder 35 in the bracket 6, substantially the same operation and effect as when the rib 80 of the reducer inlay part 29 described above is formed can be obtained.

  And the reduction gear inlay part 29, the motor case inlay part 28, and the resolver inlay part 81 are formed in the annular | circular shape centering on the axis line (rotary shaft 11) of the rotor 4, and the ribs 80, 85, 90 are along the circumferential direction. A plurality were formed at substantially equal intervals. Therefore, when the speed reducer inlay part 29, the motor case inlay part 28, and the resolver inlay part 81 expand and contract due to changes in the temperature environment, the ribs 80, 85, 90 are formed at substantially equal intervals in the circumferential direction. Each spigot part 28, 29, 81 expands and contracts substantially uniformly. That is, when the brushless motor 1 is driven, it is possible to suppress the occurrence of rattling at the joint portion between the bracket 6 and the other member (the mating member 95, the motor case 2, the resolver holder 35). Noise can be suppressed.

The technical scope of the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. That is, the specific shape, configuration, and the like given in this embodiment are merely examples, and can be changed as appropriate.
For example, in the present embodiment, a case where a plurality of ribs are formed at substantially equal intervals along the circumferential direction has been described. However, the rib thickness is appropriately changed in consideration of the structural strength of the bracket, or the rotation axis direction It may be formed obliquely with respect to. Moreover, you may form a different number of ribs in each inlay part.

It is sectional drawing of the brushless motor in embodiment of this invention. It is a top view of the bracket in the embodiment of the present invention. It is sectional drawing which follows the AA line of FIG. It is a bottom perspective view of a bracket in an embodiment of the present invention. It is a bottom view of the bracket in the embodiment of the present invention. It is a partial expanded sectional view of the junction location of the bracket and the other party member in the embodiment of the present invention. It is a partial expanded sectional view of the junction location of the bracket and motor case in the embodiment of the present invention. It is a partial expanded sectional view of the junction location of the bracket and resolver holder in the embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Brushless motor 2 ... Motor case 3 ... Stator 4 ... Rotor 5 ... Opening part 6 ... Bracket 18 ... Resolver (sensor unit) 26, 76 ... Bolt (fastening member) 28 ... Motor case inlay part (fitting inlay part) 29 ... reducer inlay part (fitting inlay part) 35 ... resolver holder (sensor unit holder) 80 ... rib 81 ... resolver inlay part (fitting inlay part) 85 ... rib 90 ... rib 95 ... mating member

Claims (2)

A motor case,
A stator fixed to the motor case;
A rotor provided rotatably with respect to the stator;
A sensor unit for detecting a rotation angle of the rotor;
In a brushless motor provided with a bracket made of a resin material that closes the opening of the motor case and rotatably supports the rotor,
The fitting inlay portion with the motor case formed on the bracket and the fitting inlay portion with the sensor unit holder that houses the sensor unit are formed in an annular shape centering on the axis of the rotor. on the outer peripheral surface of the fitting socket portion are ribs respectively formed,
The motor case is fitted on the outer peripheral surface of the fitting spigot portion with the motor case so as to contact the rib, and the outer peripheral surface of the fitting spigot portion with the sensor unit holder is fitted on the rib. The sensor unit holder is externally fitted so as to abut,
The brushless motor, wherein the motor case and the sensor unit holder are each fixed by a fastening member attached from the rotor side of the bracket and screwed from the rotor side .   The brushless motor according to claim 1, wherein a plurality of the ribs are formed at substantially equal intervals along the circumferential direction.

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