JP2005269831A - Brushless dc motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a brushless DC motor for regular winding even for a thick coil, and for a high torque with the diameter of a rotor as large as possible. <P>SOLUTION: Each tooth 18 is almost T-shaped, comprising a base part 34 and an exciting part 36, and a part of the exciting part 36 of the adjoining teeth 18 is connected each other, to constitute a teeth set member 20. A coil 30 wound on an insulating bobbin 32 is inserted from the outer peripheral side of the base part 34 of the teeth 18 in the teeth set member 20. N-pieces of fixing grooves 38 are provided in the axial direction of a cylindrical core back 16. The outer ends of the base part 34 of the teeth 18 are inserted from the opening parts of the fixing grooves 38 of the cylindrical core back 16, so that the teeth set member 20 is disposed on the inner periphery of the core back 16. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a brushless DC motor used for electric tools and hobbies.

  Conventionally, a motor has been used as a drive source for an electric tool or the like (see, for example, Patent Document 1).

A low-voltage drive and high-output brushless DC motor (hereinafter simply referred to as a motor) is often used as the drive source. Since this motor does not output unless a large amount of input current is passed, it has a large diameter. It is necessary to use a coil made of copper wire. Therefore, a space for winding this coil around the stator is made large, the diameter of the rotor is reduced, and the motor is configured to gain output by using a low torque at high speed. That is, this motor has torque but is inefficient, and has a low merit as a brushless DC motor in a high torque range.
JP 2002-18747 A

  As described above, in a conventional motor, it is effective to increase the diameter of the rotor as much as possible in order to obtain a high torque, but it is also necessary to provide a large space for winding the stator coil. Therefore, there is a problem that it is difficult to balance both of them, and in particular, in an inner rotor type motor, a coil having a large diameter cannot be formed by aligned winding.

  Therefore, in view of the above problems, the present invention provides a brushless DC motor that can perform aligned winding even with a thick coil, and can obtain a high torque by increasing the diameter of the rotor as much as possible. .

  The invention according to claim 1 is a stator in which n teeth protrude from the cylindrical core back toward the inner periphery, and a coil is wound around each of the teeth, and is rotatable to the inner periphery side of the stator. In the brushless DC motor, the n teeth are separate from the core back, and the teeth are paired in the circumferential direction from the base and the inner peripheral end of the base. The teeth are substantially T-shaped, and a portion of the excitation portions of the adjacent teeth are connected to each other to form a teeth set member, and an insulating bobbin is formed on the base of each tooth in the teeth set member. The wound coils are respectively fitted from the outer peripheral side, and n fixing grooves are provided in the axial direction of the cylindrical core back. One end of each of the fixing grooves opens at one end of the core back, and the front A brushless DC motor, wherein the teeth set members are arranged on the inner periphery of the core back by inserting the outer ends of the bases of the teeth from the openings of the fixing grooves of the cylindrical core back, respectively. It is.

  According to a second aspect of the present invention, the teeth setting member includes a ring shape in which a substantially T-shaped steel plate divided into n pieces and portions corresponding to the excitation portions in the substantially T-shaped teeth are connected to each other. The brushless DC motor according to claim 1, wherein the steel plate is laminated.

  The invention according to claim 3 is characterized in that a base portion of at least two teeth among the n teeth further protrudes from the core back, and the protruding base portion is fitted to a frame of the electric tool. The brushless DC motor according to Item 1.

  The invention according to claim 4 is the brushless DC motor according to claim 1, wherein the coil is aligned and wound around the bobbin.

  The invention according to claim 5 is a stator in which n teeth protrude from the cylindrical core back toward the inner periphery, and a coil is wound around each of the teeth, and is rotatable to the inner periphery of the stator. A brushless DC motor having a rotor disposed on the shaft, the shaft hole of the rotation shaft passes through in the axial direction of the center of the rotor core of the rotor, and at least a part of the cross section of the shaft hole is substantially D-shaped. The brushless DC motor is characterized in that a cross-sectional shape of the rotating shaft corresponding to the D-shaped shaft hole is substantially D-shaped.

  In the invention according to claim 6, a plurality of magnet insertion holes are provided in the axial direction of the rotor core, rotation magnets are respectively inserted into the magnet insertion holes, and a pair of cooling fans are provided at both ends of the rotor. 5. The brushless DC motor according to claim 4, wherein the brushless DC motor is disposed, and a magnet for rotation inside each of the magnet insertion holes is sandwiched between the pair of cooling fans.

  In the invention according to claim 7, a ring-shaped position detection magnet is provided on one of the pair of cooling fans, and a magnetic detection element for detecting the rotational position of the rotor in the vicinity of the position detection magnet is provided. The brushless DC motor according to claim 4, wherein the brushless DC motor is provided.

  The invention according to claim 8 is the brushless DC motor according to claim 1, wherein the cylindrical core back is formed by stacking by caulking a ring-shaped steel plate into a cylindrical shape. It is.

  The invention according to claim 9 is the brushless DC motor according to claim 1, wherein the cylindrical core back is integrally formed by casting or pressing iron.

  A brushless DC motor according to the first aspect of the present invention will be described.

  The core back and teeth of the stator of this brushless DC motor are separate bodies, each tooth is substantially T-shaped, and a part of the exciting portions of the adjacent teeth is connected to each other to form a cylindrical shape. A teeth set member is configured.

  Then, a coil is wound around an insulating bobbin, and the bobbin around which the coil is wound is fitted into the base of each tooth from the outer peripheral side. In the axial direction of the cylindrical core back, n fixed grooves are provided, and the outer ends of the base portions of the plurality of teeth are respectively inserted from the openings of the fixed grooves to the inner periphery of the core back. Arrange teeth with coils.

  This simplifies the assembly of the stator of the brushless DC motor, minimizes the winding space of the coil, and increases the diameter of the rotor, so that the generated torque can be increased.

  In the brushless DC motor according to the second aspect of the present invention, the teeth set member includes n approximately divided T-shaped steel plates and n approximately integrated members in which a part of the excitation part is connected to each other. Since it is formed by laminating a T-shaped steel plate, the teeth set member can be easily configured.

  In the brushless DC motor according to the third aspect of the present invention, since the base portions of at least two teeth out of the n teeth protrude further than the core back, the protruding base portion is fitted to the frame of the electric tool. Thus, the brushless DC motor can be fixed to the frame of the electric tool.

  In the brushless DC motor according to the fourth aspect of the present invention, the coil is aligned and wound around the bobbin, and the coil is simply wound around the bobbin, so that the aligned winding can be easily performed.

  In the brushless DC motor of the invention according to claim 5, since the cross-sectional shape corresponding to the D-shaped insertion hole only press-fits the D-shaped rotating shaft into the rotor core, the press-fitting operation is easily performed. And the occurrence of bending of the rotating shaft can be prevented. Further, the function of preventing the rotor from rotating can be reliably performed with respect to the torque generated by the motor.

  In the brushless DC motor according to the sixth aspect of the present invention, since the rotor is sandwiched between the pair of cooling fans, the rotating magnets in the respective magnet insertion holes are sandwiched.

  In the brushless DC motor according to the seventh aspect of the present invention, since the position detecting magnet and the cooling fan are provided integrally, the size of the rotor can be reduced, and the assembly is facilitated.

  In the brushless DC motor according to the eighth aspect of the invention, the cylindrical core back is formed by stacking by caulking a ring-shaped steel plate to form a cylindrical shape. , Motor efficiency is good.

  In the brushless DC motor of the invention according to claim 9, since the cylindrical core back is integrally formed by casting or pressing iron, it is easy to manufacture.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.

  A three-phase brushless DC motor (hereinafter simply referred to as a motor) 10 of the present embodiment is a motor for an electric tool, and is used by being housed inside a frame of the electric tool.

  Hereinafter, the structure of the motor 10 will be described separately for the stator 12 and the rotor 14.

(1) Stator 12
The structure of the stator 12 will be described together with the manufacturing method.

  The stator 12 includes a cylindrical core back 16 and six teeth 18 protruding from the inner peripheral side of the core back 16, and the six teeth 18 integrally form a teeth set member 20. doing.

(1-1) Teeth setting member 20
First, the teeth setting member 20 will be described with reference to FIGS.

  The teeth set member 20 is formed by laminating a plurality of (for example, 85) steel plates, and the steel plates are formed from four types of steel plates 22, 24, 26, and 28 as shown in FIGS. Has been.

  As shown in FIG. 8, the type 1 steel plate 22 is formed by connecting six substantially T-shaped steel plate portions 22 a. The two ends of the exciting portion 22b projecting in the circumferential direction from the inner peripheral end of the base portion of the tooth 18 are connected to each other and formed in a ring shape. Of the six base portions of the teeth 18, four base portions 22 c have the same length as the outer diameter of the core back 16, and the remaining two base portions 22 d are longer than the outer diameter of the core back 16. More prominent. The base portions 22d and 22d are provided at positions facing each other.

  As shown in FIG. 9, the type 2 steel plate 24 is composed of six steel plate portions 24a, and each steel plate portion 24a is independent. The steel plate portion 24a is substantially T-shaped, and the excitation portion 24b protrudes from both sides of the inner peripheral end of the base portion 24c. The length of the base portion 24 c is the same length as the outer diameter of the core back 16.

  As shown in FIG. 10, the type 3 steel plate 26 includes six steel plate portions 26a, and each steel plate portion 26a is independent. The steel plate part 26a is substantially T-shaped, and the excitation part 26b protrudes from both sides of the inner peripheral end of the base part 26c. The length of the base portion 26 c is the same length as the inner diameter of the core back 16.

  As shown in FIG. 11, the type 4 steel plate 28 is formed in a ring shape by connecting six steel plate portions 28a. The steel plate portion 28a is substantially T-shaped, and the excitation portion 28b protrudes from both sides of the inner peripheral end of the base portion 28c, and is connected to the adjacent steel plate portion 28a by this excitation portion 28b. The length of the base portion 28 c is the same length as the inner diameter of the core back 16.

  The teeth set member 20 is formed by laminating the steel plates 24 to 28 of the respective types punched as described above while crimping. After 15 type 1 steel plates 22 are stacked, 28 type 2 steel plates 24 are stacked, then 27 type 3 steel plates 26 are stacked, and finally 15 type 4 steel plates 28 are stacked.

  As described above, the teeth setting member 20 is configured as shown in FIG. The teeth set member 20 has a structure in which six teeth 18 are integrated by laminating these steel plates 22 to 28. Each T-shaped tooth 18 includes a radially extending base 34 and an inner peripheral end thereof. It is formed from the excitation part 36 which protruded from both sides.

(1-2) Winding of Coil 30 Next, the coil 30 is wound around the teeth set member 20. In this winding method, a coil 30 made of copper wire is wound around six insulating bobbins 32 in an aligned manner. Thereafter, the bobbins 32 around which the coils 30 are wound are inserted from the outer peripheral sides of the six base portions 34 of the teeth set member 20.

(1-3) Assembly of Teeth Set Member 20 and Cylindrical Core Back 16 Next, as shown in FIGS. 2 to 4, the teeth set member 20 to which six coils 30 are attached is attached to the cylindrical core back 16. Insert in the inner circumference.

  The cylindrical core back 16 is formed by stacking by caulking ring-shaped steel plates to form a cylinder. Six fixing grooves 38 are provided in the axial direction of the cylindrical core back 16. Each of the fixing grooves 38 is opened at one end portion of the core back 16.

  Six base portions 34 of the teeth setting member 20 are inserted from the openings of the fixing grooves 38. In this case, the axial length of the fixing groove 38 is the same as the dimension in which the type 1 steel plate 22 and the type 2 steel plate 24 are laminated. That is, when the teeth setting member 20 is inserted into the inner peripheral side of the core back 16, the base 22c of the type 1 steel plate 22 and the base 24c of the type 2 steel plate 24 protrude from the fixing groove 38, and the type 3 steel plate 26 The base portion 26 c and the base portion 28 c of the type 4 steel plate 28 are arranged on the inner peripheral side of the core back 16.

(1-4) Crossover wiring and common wiring After arranging the tooth set member 20 in the core back 16 as described above, next, the crossover wiring and the common wiring are performed. This wiring will be described with reference to FIG.

  Since the coil 30 of the motor 10 is Y-connected, it is necessary to perform a common wiring and a crossover wiring for each phase that are connected at the center.

  For the U phase, the coil 30 wound counterclockwise around the first tooth 18 is connected to the coil 30 wound counterclockwise around the fourth tooth 18.

  For the V phase, the coil 30 wound counterclockwise around the sixth tooth 18 is connected to the coil 30 wound counterclockwise around the third tooth 18.

  In the W phase, the coil 30 wound counterclockwise around the fifth tooth 18 is connected to the coil 30 wound counterclockwise around the second tooth 18.

  Thereafter, one end of the three-phase coils 30, 30, and 30 are connected to perform common wiring.

  As described above, the stator 12 is assembled. Note that two base portions 22 d of the type 1 steel plate 22 protrude from the core back 16. As will be described later, the protruding base portion 22d can be inserted into the groove of the power tool frame to fix the stator 12 to the power tool frame.

(2) Rotor 14
The structure of the rotor 14 will be described together with the manufacturing method. The front end of the rotor 14 is the output side, and the rear end is the non-output side.

(2-1) Formation of Rotor Core 40 As shown in FIGS. 5 to 7, the rotor core 40 is formed by laminating a plurality of circular steel plates. A shaft hole 42 is formed at the center of the rotor core 40, and 8 magnet insertion holes 44 for inserting S-pole and N-pole rod-shaped rotation magnets 74, 76 are provided outside the shaft hole 42. It penetrates. A fixing hole 48 passes between the shaft hole 42 and the eight magnet insertion holes 44.

  As for the shape of the shaft hole 42, the half of the axial length of the rotor core 40 is circular in cross section (see FIGS. 5 and 7), and the other half is D in cross section (see FIG. (See FIG. 6).

(2-2) Attachment of Rotating Shaft 50 and Rotating Magnets 74 and 76 The rotating shaft 50 is press-fitted into the shaft hole 42 of the rotor core 40. The rotating shaft 50 has a circular section and a D-shaped section, and the D-shaped rotating shaft 50 is fitted into the shaft hole 42 having a D-shaped section (see FIG. 6). By this fitting, rotation prevention of the rotor core 40 and the rotating shaft 50 can be performed, and the bending of the rotating shaft 50 can be prevented.

  Next, S-pole rotating magnets 74 and N-pole rotating magnets 76 are alternately inserted into the eight magnet insertion holes 44, respectively.

(2-3) Mounting of cooling fans 52 and 54 Next, mounting of the synthetic resin cooling fans 52 and 54 to both ends of the rotor core 40 will be described with reference to FIGS. .

  As shown in FIG. 1, the cooling fan 52 attached to the front end of the rotor 14 has a through hole 56 through which the rotation shaft 50 passes, and eight blades 58 are provided around it as shown in FIG. It has been. Further, four fixing protrusions 70 are provided on the rotor 14 side of the cooling fan 54 and are inserted into four fixing holes 48 opened in the stator core 40, so that the cooling fan 54 is connected to the rotor core 40. On the other hand, it can be fixed at a predetermined position.

  As shown in FIGS. 1 and 2, the cooling fan 54 attached to the rear end of the rotor 14 is provided with a through hole 60 through which the rotary shaft 50 penetrates at the center of the cooling fan 54, and eight blades around it. 62 is provided.

  A concave portion 64 is formed in the central portion of the eight blades 62, and a ring-shaped position detecting magnet 64 is fitted as shown in FIG. As shown in FIGS. 13 and 15, an engagement hole 66 is provided in the recess 64, and a protrusion 68 protruding from the position detection magnet 64 is fitted into the recess 64. Can be positioned. The position detection magnet 64 is fixed by providing a protrusion 65 at the edge of the recess 64 and melting the protrusion 65 with heat to cover the edge of the position detection magnet 64.

  In addition, four fixing protrusions 72 protrude from the cooling fan 52 on the rotor 14 side, and are inserted into the fixing holes 48 of the stator core 40.

  The eight rotation magnets 74 and 76 are held between the pair of cooling fans 54 and 56 and are not removed from the rotor core 40.

  Finally, bearings 78 and 80 are attached to the front end portion and the rear end portion of the rotating shaft 50, respectively.

(3) Final assembly of motor 10 The rotor 14 is arranged on the inner peripheral side of the stator 12 manufactured as described above, and then the motor 10 is inserted into the frame of the electric tool.

  In this case, as described above, the base portion 22d of the type 1 steel plate 22 is fitted in the groove of the frame of the electric power tool, and the motor 10 is fixed inside the frame of the electric power tool.

  When the motor 10 is arranged inside the frame of the electric tool, a Hall IC is arranged in the vicinity of the position detection magnet 64, and the rotation state of the rotor 14 is detected by the Hall IC.

(5) Effects of the present embodiment The motor 10 having the above configuration has the following effects.

  Since the winding space for winding the coil 30 is kept to a minimum, the diameter of the rotor 14 can be increased and the generated torque can be increased. Therefore, the motor efficiency at high torque can be improved, and a large load can be dealt with. Further, since the same torque can be obtained by reducing the rotation speed, noise vibration can be suppressed.

  Since the coil 30 is simply wound around the bobbin 32 by aligned winding and fitted into the teeth set member 20, the winding work is simplified. Further, it is possible to form the motor 10 having the same output and a smaller outer diameter than the conventional one.

  Since the rotation shaft is D-shaped and the shaft hole 42 of the stator core 40 is D-shaped, the rotation preventing function of the rotor 14 can be reliably achieved. Further, the rotor 14 can be easily assembled. Furthermore, the bending of the rotating shaft 50 can be prevented.

(Second Embodiment)
A motor 10 according to a second embodiment will be described with reference to FIGS.

  The motor 10 of the present embodiment is a thin type motor 10 corresponding to a frame that is thinner than the electric tool of the first embodiment, and the diameters of the rotor 14 and the stator 12 are reduced.

  Even the motor 10 of this embodiment can be easily assembled and the winding work is also simplified.

  Moreover, even if the diameter of the motor 10 is small, higher torque can be obtained than before.

(Example of change)
In the above-described embodiment, the cylindrical core back 16 is formed by stacking by caulking ring-shaped steel plates to form a cylinder, but instead, the cylindrical core back 16 is made of iron. May be formed by casting or pressing.

  The brushless DC motor of the present invention is suitable for an electric tool or a hobby motor, and particularly suitable for a motor that rotates by a battery drive system.

It is a longitudinal cross-sectional view of the motor of 1st Embodiment. It is a side view of a motor similarly. It is a front view of a motor. It is a rear view of a motor. It is the sectional view on the AA line in FIG. It is the BB sectional view taken on the line in FIG. It is CC sectional view taken on the line in FIG. It is a front view of a type 1 steel plate. It is a front view of a type 2 steel plate. It is a front view of a type 3 steel plate. It is explanatory drawing of the steel plate of type 4. It is a longitudinal cross-sectional view of a teeth set member. It is a longitudinal cross-sectional view of a cooling fan. It is a front view of a cooling fan. It is a rear view of a cooling fan. It is a figure explaining the winding method. It is a longitudinal cross-sectional view of the motor of 2nd Embodiment. It is the DD sectional view taken on the line in FIG. It is the EE sectional view taken on the line in FIG. It is the FF sectional view taken on the line in FIG. It is the GG sectional view taken on the line in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Motor 12 Stator 14 Rotor 16 Core back 18 Teeth 20 Teeth set member 22 Type 1 steel plate 24 Type 2 steel plate 26 Type 3 steel plate 28 Type 4 steel plate 30 Coil 32 Bobbin 34 Base 36 Excitation part 38 Fixing groove 40 Stator core 42 Insertion hole 44 Magnet insertion hole 48 Fixed hole 50 Rotating shaft 52 Cooling fan 54 Cooling fan 64 Position detection magnet

Claims (9)

N teeth protrude from the cylindrical core back toward the inner periphery, and a stator in which a coil is wound around each of the teeth,
A rotor disposed rotatably on the inner periphery of the stator;
In a brushless DC motor having
The n teeth are separate from the core back,
Each of the teeth has a substantially T-shape in which a pair of exciting portions protrude in the circumferential direction from the inner peripheral end of the base portion and the base portion, and a part of the exciting portions of the adjacent teeth is connected to each other to form a teeth setting member Is configured,
The coils wound around the insulating bobbin are respectively fitted from the outer peripheral side to the base of each tooth in the teeth set member,
N fixing grooves are provided in the axial direction of the cylindrical core back, and one ends of these fixing grooves open at one end of the core back;
The brushless DC, wherein the teeth set members are arranged on the inner periphery of the core back by inserting the outer ends of the base portions of the teeth from the openings of the fixing grooves of the cylindrical core back, respectively. motor. The teeth set member is
A substantially T-shaped steel plate divided into n pieces and a ring-shaped steel plate in which portions corresponding to the exciting portions in the substantially T-shaped teeth are connected to each other are laminated. Item 2. A brushless DC motor according to Item 1. A base of at least two teeth out of the n teeth further protrudes from the core back;
The brushless DC motor according to claim 1, wherein the protruding base portion is fitted into a frame of an electric tool. The brushless DC motor according to claim 1, wherein the coil is wound around the bobbin. N teeth protrude from the cylindrical core back toward the inner periphery, and a stator in which a coil is wound around each of the teeth,
A rotor arranged rotatably on the inner periphery of the stator;
In a brushless DC motor having
The shaft hole of the rotating shaft penetrates in the axial direction of the center of the rotor core of the rotor,
At least a part of the cross section of the shaft hole is substantially D-shaped,
The brushless DC motor, wherein a cross-sectional shape of the rotating shaft corresponding to the D-shaped shaft hole is substantially D-shaped. A plurality of magnet insertion holes are provided in the axial direction of the rotor core,
A magnet for rotation is inserted into each of the magnet insertion holes,
A pair of cooling fans are arranged at both ends of the rotor,
The brushless DC motor according to claim 4, wherein a rotating magnet inside each magnet insertion hole is sandwiched between the pair of cooling fans. A ring-shaped position detection magnet is provided on one of the pair of cooling fans,
The brushless DC motor according to claim 4, wherein a magnetic detection element for detecting a rotational position of the rotor is provided in the vicinity of the position detection magnet. The brushless DC motor according to claim 1, wherein the cylindrical core back is formed by stacking by caulking a ring-shaped steel plate to form a cylindrical shape. The brushless DC motor according to claim 1, wherein the cylindrical core back is integrally formed by casting or pressing iron.

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