KR100668946B1 - Brushless dc motor - Google Patents

Abstract

The present invention provides a brushless DC motor that can be wound even if the coil is thick, and can obtain a high torque by making the diameter of the rotor as large as possible.

Each tooth portion 18 has a substantially T-shape consisting of a base portion 34 and an excitation portion 36, and a portion of the excitation portion 36 of the adjacent tooth portion 18 is connected to each other so that the tooth set member 20 ), The coil 30 wound around the insulating bobbin 32 to the base 34 of each tooth 18 in the tooth set member 20 is fitted from the outer circumferential side, respectively. The n fixing grooves 38 are formed in the axial direction of the core bag 16 having a shape, and the base portions of the plurality of teeth 18 are formed from the openings of the respective fixing grooves 38 of the cylindrical core bag 16. 34, the outer end of each is inserted so that the tooth set member 20 is disposed on the inner circumference of the core bag 16. As shown in FIG.

Description

Brushless DC Motors {BRUSHLESS DC MOTOR}

1 is a longitudinal sectional view of a motor according to a first embodiment.

2 is a side view of a motor according to a first embodiment.

3 is a front view of the motor according to the first embodiment.

4 is a rear view of the motor according to the first embodiment.

5 is a cross-sectional view taken along the line A-A of FIG.

6 is a cross-sectional view taken along the line B-B in FIG.

7 is a cross-sectional view taken along the line C-C in FIG.

8 is a front view of a steel sheet of type 1;

9 is a front view of a steel sheet of type 2;

10 is a front view of a steel sheet of type 3;

11 is an explanatory diagram of a steel sheet of type 4;

12 is a longitudinal sectional view of a tooth set member;

13 is a longitudinal sectional view of a cooling fan.

14 is a front view of the cooling fan.

15 is a rear view of the cooling fan.

16 is a diagram illustrating a winding method.

17 is a longitudinal cross-sectional view of a motor according to a second embodiment.

18 is a cross-sectional view taken along the line D-D of FIG. 17;

19 is a cross-sectional view taken along the line E-E of FIG.

20 is a cross-sectional view taken along the line F-F in FIG. 17;

FIG. 21 is a cross-sectional view taken along the line G-G of FIG. 17;

Explanation of symbols on the main parts of the drawings

10 motor 12 stator

14: rotor 16: core bag

18: teeth 20: teeth set member

22: steel plate of type 1 24: steel plate of type 2

26: type 3 steel plate 28: type 4 steel plate

30: coil 32: bobbin

34: base part 36: woman part

38: fixing groove 40: rotor core

42: shaft hole 44: magnet insertion hole

48: fixing hole 50: rotation axis

52: cooling fan 54: cooling fan

64: magnet for position detection 67: recessed portion

The present invention relates to a brushless DC motor used for power tools and hobby.

Conventionally, a motor is used as a drive source, such as an electric tool (for example, refer patent document 1).

The motor used as a driving source is a low voltage drive and a high output brushless DC motor (hereinafter, simply referred to as a motor), which is often used, and since the motor does not generate an output unless a large amount of input current flows, the diameter is large. It is necessary to use a coil made of thick copper wire. For this reason, it is a motor which has a large space for winding this coil to a stator, makes the diameter of a rotor small, and obtains output by high speed use of low torque. That is, such a motor obtains torque but is poor in efficiency, so that the value as a brushless DC motor becomes low in a high torque region.

[Patent Document 1] Japanese Patent Laid-Open No. 2002-18747

As described above, in order to obtain high torque, it is effective to make the diameter of the rotor as large as possible, but it is difficult to balance the two because it is necessary to secure a large space for winding the coil on the stator. In particular, there is a problem in that a coil having a large diameter cannot be aligned and wound in an internal rotor type motor.

Accordingly, it is an object of the present invention to provide a brushless DC motor that can be wound evenly coarse even when the coil is thick, and can obtain a high torque by making the diameter of the rotor as large as possible.

The invention according to claim 1, wherein n teeth are protruded from the cylindrical core bag toward the inner circumference, and coils are wound around the teeth, respectively, and are arranged to be rotatable on the inner circumferential side of the stator. 12. A brushless DC motor having a fixed rotor, wherein the n teeth are separate from the core bag, and each tooth is a substantially T-shape in which a pair of excitation portions protrude from the inner circumferential end of the base portion and the base portion. In addition, a portion of the excitation portion of the adjacent tooth portion is connected to each other to form a tooth set member, and the coils wound around an insulating bobbin on the base portion of each tooth portion in the tooth set member are fitted from the outer peripheral side, respectively. N fixing grooves are formed in the axial direction of the cylindrical core bag, and one end of the fixing groove is opened at one end of the core bag. , The tubular core is inserted into the bag through the opening of the respective fixing grooves respectively have the respective teeth of the outer end of the base portion, wherein the core the inner periphery of the bag value is a brushless DC motor, it characterized in that the male part is set member is arranged.

The invention according to claim 2, wherein the tooth set member is laminated with an approximately T-shaped steel sheet divided into n and a ring-shaped steel sheet in which portions corresponding to the excitation portions in the approximately T-shaped teeth are connected to each other. The brushless DC motor according to claim 1, which is formed.

The brush according to claim 1, wherein the base of at least two teeth of the n teeth is more protruded than the core bag, and the protruding base is fitted into the frame of the power tool. It is a lease DC motor.

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

The invention according to claim 5 includes a stator with n teeth protruding from the cylindrical core bag toward the inner circumference and a coil wound around each tooth, and a rotor disposed to be rotatable on the inner circumferential side of the stator. A brushless DC motor having: a shaft hole of a rotating shaft penetrates in an axial direction of a rotor core center of the rotor, and at least a part of a cross section of the shaft hole is approximately D-shaped, and is formed in the D-shaped shaft hole. The cross-sectional shape of the corresponding rotating shaft is a substantially D-shape, the brushless DC motor.

The invention according to claim 6, wherein a plurality of magnet insertion holes are formed in the axial direction of the rotor core, a rotating magnet is inserted into each of the magnet insertion holes, and a pair of cooling fans are disposed at both ends of the rotor. The rotation magnet inside each said magnet insertion hole is hold | maintained by the said pair of cooling fan, The brushless DC motor of Claim 4 characterized by the above-mentioned.

The invention according to claim 7 is provided with a ring-shaped position detecting magnet on one side of the pair of cooling fans, and a magnetic detecting element for detecting the rotational position of the rotor in the vicinity of the position detecting magnet. It is the brushless DC motor of Claim 4 characterized by the above-mentioned.

The invention according to claim 8 is the brushless DC motor according to claim 1, wherein the cylindrical core bag is laminated by caulking a ring-shaped steel sheet and formed into a cylindrical shape.

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

 (1st embodiment)

EMBODIMENT OF THE INVENTION Hereinafter, 1st Embodiment of this invention is described based on FIG.

The three-phase brushless DC motor 10 (hereinafter, simply referred to as a "motor") of the present embodiment is used after being housed inside a frame of a power tool as a power tool motor.

The structure of the motor 10 will be described below by dividing into 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 is composed of a cylindrical core bag 16 and six teeth 18 protruding from the inner circumferential side of the core bag 16, and the six teeth 18 are integrated to form a toothed part. The set member 20 is constituted.

(1-1) tooth set member 20

First, the tooth set member 20 will be described based on FIGS. 8 to 12.

The tooth set member 20 is obtained by stacking a plurality of sheets (for example, 85 sheets) of steel sheets, and the steel sheets are four types of steel sheets 22, 24, 26, 28 as shown in Figs. )

As shown in Fig. 8, the type 1 steel plate 22 is formed by connecting six steel plate portions 22a having a substantially T shape. Both ends of the excitation portion 22b protruding in the circumferential direction from the inner circumferential end of the base portion of the tooth portion 18 are connected to each other and are formed in a ring shape. Of the six base portions of the teeth 18, four base portions 22c are equal to the length of the outer diameter of the core bag 16, and the remaining two base portions 22d are longer than the outer diameter of the core bag 16. It protrudes more than the core bag 16 (see FIG. 5). The base portions 22d and 22d are formed at positions facing each other.

As shown in FIG. 9, the type 2 steel plate 24 is comprised from six steel plate parts 24a, and each steel plate part 24a is independent. The steel plate part 24a is substantially T-shaped, and the excitation part 24b protrudes from both sides of the inner peripheral end of the base part 24c. The length of the base portion 24c is equal to the length of the outer diameter of the core bag 16.

As shown in FIG. 10, the type 3 steel plate 26 is comprised from six steel plate parts 26a, and each steel plate part 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 26c is equal to the length of the inner diameter of the core bag 16 (see FIG. 6).

As shown in FIG. 11, the type 4 steel plate 28 is formed by ring-shaped six steel plate parts 28a connected. The steel plate part 28a is substantially T-shaped, and the excitation part 28b protrudes from both sides of the inner peripheral end of the base part 28c, and is connected with the adjacent steel plate part 28a by the said excitation part 28b. The length of the base portion 28c is equal to the length of the inner diameter of the core bag 16 (see FIG. 7).

As described above, each type of punched steel sheets 24 to 28 is laminated while caulking to form the tooth set member 20. After stacking 15 sheets of type 1 steel sheets 22, 28 sheets of type 2 steel sheets 24 were laminated, then 27 sheets of type 3 steel sheets 26 were laminated, and finally, type 4 steel sheets ( 15 sheets 28) are laminated.

As described above, as shown in FIG. 12, the tooth set member 20 is configured. The tooth set member 20 has a structure in which six teeth 18 are integrated by laminating these steel sheets 22 to 28, and each of the T-shaped teeth 18 extends radially. It is formed with the base part 34 and the excitation part 36 which protruded from both sides of the inner peripheral end.

(1-2) winding of coil 30

Next, the coil 30 is wound around the tooth set member 20. The winding method arranges and winds the coil 30 which consists of copper wires to six insulating bobbins 32. As shown in FIG. Thereafter, the bobbin 32 wound around the coil 30 is inserted from the outer circumferential side of the six base portions 34 of the tooth set member 20, respectively.

(1-3) Assembly of the tooth set member 20 and the cylindrical core bag 16

Next, as shown in FIGS. 2 to 4, the tooth set member 20 with six coils 30 is inserted into the inner circumference of the cylindrical core bag 16.

The cylindrical core bag 16 is laminated | stacked by caulking a ring-shaped steel plate, and is formed in cylindrical shape. Six fixing grooves 38 are formed in the axial direction of the cylindrical core bag 16. The fixing grooves 38 are open at one end of the core bag 16, respectively.

The six base parts 34 of the tooth set member 20 are inserted from the opening of the fixing groove 38. In this case, the length of the fixing groove 38 in the axial direction is the same length as the size in which the steel sheet 22 of type 1 and the steel sheet 24 of type 2 are laminated. That is, when the tooth set member 20 is inserted into the inner circumferential side of the core bag 16, the base portion 22c of the steel plate 22 of the type 1 and the steel plate 24 of the type 2 are removed from the fixing groove 38. The base portion 24c protrudes, and the base portion 26c of the steel plate 26 of the type 3 and the base portion 28c of the steel plate 28 of the type 4 are disposed on the inner circumferential side of the core bag 16.

(1-4) Bus Wiring and Common Wiring

As described above, after the tooth set member 20 is disposed inside the core bag 16, bus wiring and common wiring are performed. Such wiring will be described based on FIG.

Since the coil 30 of the motor 10 is Y-connected, it is necessary to perform common wiring to be connected at the center thereof and bus wiring of each phase.

In the U phase, the coil 30 wound counterclockwise on the first teeth 18 is connected to the coil 30 wound counterclockwise on the fourth teeth 18.

In the V phase, the coil 30 wound counterclockwise on the sixth teeth 18 is connected to the coil 30 wound counterclockwise on the third teeth 18.

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

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

As a result, the stator 12 is assembled. In addition, two base portions 22d of the steel plate 22 of the type 1 protrude from the core bag 16. As described later, the protruding base portion 22d is inserted into the frame groove of the power tool, so that the stator 12 can be fixed to the frame of the power tool.

(2) rotor (14)

The structure of the rotor 14 is demonstrated with a manufacturing method. The front end of the rotor 14 is the output side, and the rear end is the half output side.

(2-1) Formation of Rotor Core 40

As shown in Figs. 5 to 7, a plurality of circular steel sheets are stacked to form the rotor core 40. Figs. Eight magnets for inserting shaft holes 42 and rod-shaped rotating magnets 74 and 76 of the S pole and the N pole in the outer direction of the shaft hole 42 in the center of the rotor core 40. The insertion hole 44 penetrates through. In addition, a fixing hole 48 penetrates between the shaft hole 42 and the eight magnet insertion holes 44.

The shape of the shaft hole 42 is about half of the axial length of the rotor core 40 is circular in cross-sectional shape (see FIGS. 5 and 7), and the other half is in cross-sectional shape D. It is a child shape (refer FIG. 6).

(2-2) Attachment of the Rotating Shaft 50 and the 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 portion having a circular cross section and a portion having a D-shaped cross section, and the rotating shaft 50 having a D shape is fitted into the shaft hole 42 having a D-shaped cross section (see FIG. 6). ). By this insertion, rotation of the rotor core 40 and the rotating shaft 50 can be prevented, and bending of the rotating shaft 50 can be prevented.

Next, the rotation magnet 74 of the S pole and the rotation magnet 76 of the N pole are alternately inserted into the eight magnet insertion holes 44.

(2-3) Attaching the Cooling Fans 52 and 54

Next, attachment of the synthetic resin cooling fans 52 and 54 to both ends of the rotor core 40 will be described based on FIGS. 1 to 4 and 13 to 15.

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 rotating shaft 50 penetrates in the center thereof, and is shown in FIG. 3 around the cooling fan 52. As described above, eight blades 58 are provided. In addition, four fixing protrusions 70 are formed on the rotor 14 side of the cooling fan 54, and inserted into four fixing holes 48 that are opened in the rotor core 40 to form a cooling fan ( 54 can be fixed at a predetermined position with respect to the rotor core 40.

As shown in FIGS. 1 and 2, the cooling fan 54 attached to the rear end of the rotor 14 includes a through hole 60 through which the rotation shaft 50 passes through the center of the cooling fan 54. It is formed and eight wings 62 are formed around it.

A recessed portion 67 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, the concave portion 67 has a coupling hole 66 formed therein, and a projection 68 projecting from the position detecting magnet 64 is fitted thereinto, and the position detecting magnet ( 64 may be positioned relative to the recess 67. The position detecting magnet 64 is fixed by melting the protrusion 65 formed at the edge portion of the recess 67 with heat to cover the edge portion of the position detecting magnet 64.

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

By the pair of cooling fans 52, 54, eight rotating magnets 74, 76 are held in place and do not come out of the rotor core 40.

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

(3) final assembly of the motor 10

The rotor 14 is disposed on the inner circumferential side of the stator 12 manufactured as described above, and then the motor 10 is inserted into the frame of the power tool.

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

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

(5) Effect of this embodiment

According to the motor 10 of the said structure, the following effects are acquired.

Since the winding space for winding the coil 30 is minimized, the diameter of the rotor 14 can be increased, and the generated torque can be increased. As a result, the motor efficiency at high torque can be improved, and a large load can be coped with. In addition, since the same torque can be obtained by slowing down the rotation speed, noise vibration can be suppressed.

Since the coil 30 is wound around the bobbin 32 by alignment winding and only inserted into the tooth set member 20, the winding operation is simplified. In addition, a motor 10 having a smaller outer diameter than the conventional one can be formed at the same output.

Since the rotating shaft is D-shaped and the shaft hole 42 of the rotor core 40 is D-shaped, the rotation preventing function of the rotor 14 can be reliably performed. In addition, the assembly of the rotor 14 can also be facilitated. Moreover, the bending of the rotation shaft 50 can be prevented.

(2nd embodiment)

The motor 10 of 2nd Embodiment is demonstrated with reference to FIGS. 17-21.

The second embodiment is a slim motor 10 corresponding to a narrower frame than the first embodiment.

The cooling fan structure, the bobbin structure, and the shaft structure have the same structure and the same effect and effect as that of the first embodiment and the second embodiment except that the diameters are different.

The difference of 2nd Embodiment is that the diameter of a rotor is made small, and the rotating magnets 74 and 76 arrange four magnets in square shape. In addition, the stator core makes the diameter of each type of core of FIGS. 8-11 small. However, regarding type 1, the size of the base part 22d is the same as that of the type 2 base part 24a, and is the same length as the outer diameter of the core bag 16. As shown in FIG. Thus, in FIG. 12 of the first embodiment, the stator 20 has three stages, whereas in FIG. 17 of the second embodiment, the shape of the stator core 12 has two stages.

(Change example)

In the above embodiment, the cylindrical core bag 16 is formed by stacking a ring-shaped steel sheet by caulking, but instead the cylindrical core bag 16 is cast or pressed by You may form integrally.

The brushless DC motor of the invention according to claim 1 will be described.

The core back and the teeth of the stator of the brushless DC motor are separate, each tooth is substantially T-shaped, and a portion of the excitation of the adjacent teeth is connected to each other to form a cylindrical tooth set member.

The coil is wound around an insulating bobbin, and the bobbin in which the coil is wound is inserted into the base portion of each tooth portion from the outer peripheral side. In the axial direction of the cylindrical core bag, n fixing grooves are formed, and outer ends of the base portions of the plurality of teeth are inserted from the openings of the fixing grooves, respectively, and teeth having a coil are disposed on the inner circumference of the core bag.

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

In the brushless DC motor of the invention according to claim 2, a substantially T-shaped steel sheet in which the tooth set member is divided into n and n approximately T-shaped steel sheets in which a part of the excitation portion is connected to each other and integrated is laminated. Since it is made, the tooth set member can be easily configured.

In the brushless DC motor of the invention according to claim 3, since the base of at least two teeth of the n teeth is more protruding than the core bag, the brushless DC motor is fitted by fitting the protruding base to the frame of the power tool. Can be fixed to the frame of the power tool.

In the brushless DC motor of the invention according to claim 4, the coil is aligned and wound around the bobbin, and the coil is simply wound around the bobbin, thereby facilitating alignment winding.

In the brushless DC motor of the invention according to claim 5, the press-fitting operation can be facilitated because only the rotary shaft whose cross-sectional shape corresponding to the D-shaped insertion hole is D-shaped is press-fitted into the rotor core. It is also possible to prevent warpage of the rotating shaft. In addition, the rotation preventing function of the rotor can be ensured in relation to the generated torque of the motor.

In the brushless DC motor of the invention according to claim 6, since the rotor is held by a pair of cooling fans, the rotating magnets inside the magnet insertion holes are held in place.

In the brushless DC motor of the invention according to claim 7, since the magnet for position detection and the cooling fan are integrally provided, the size of the rotor can be reduced and assembly is also easy.

In the brushless DC motor of the eighth aspect of the invention, the tubular core bag is formed by stacking the steel sheet by caulking the ring to form a tubular shape, so that it is easy to manufacture and the motor efficiency is good.

In the brushless DC motor of the ninth aspect of the present invention, the cylindrical core bag is easily formed by casting or pressing iron to form a single body.

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

Claims (9)

A stator 12 having n teeth 18 protruding from the cylindrical core bag 16 toward the inner circumference, and coils 30 wound around the teeth 18, respectively; A brushless DC motor having a rotor 14 rotatably disposed on an inner circumferential side of the stator 12, The n teeth 18 are separate from the core bag 16, Each of the teeth 18 has a substantially T-shape in which a base portion 34 and a pair of excitation portions 36 protrude from the inner circumferential end of the base portion 34 in the circumferential direction, and the adjacent teeth portion ( A part of the excitation part 36 of 18 is connected to each other to form a tooth set member 20, The coils 30 wound around the insulating bobbin 32 are inserted into the base 34 of each tooth 18 in the tooth set member 20 from the outer circumferential side, respectively. N fixing grooves 38 are formed in the axial direction of the cylindrical core bag 16, and one end of these fixing grooves 38 is opened at one end of the core bag 16, The outer end portions of the base portions 34 of the teeth are inserted from the openings of the fixing grooves 38 of the cylindrical core bag 16, respectively, and the tooth set member is formed on the inner circumference of the core bag 16. Brushless DC motor, characterized in that 20 is disposed. The method of claim 1, The tooth set member 20 is formed in a ring shape in which a substantially T-shaped steel sheet divided into n pieces and a portion corresponding to the excitation portion 36 in the approximately T-shaped teeth 18 are connected to each other. Brushless DC motor, characterized in that the steel sheet is laminated. The method of claim 1, The base 34 of at least two teeth of the n teeth 18 protrudes more than the core bag 16, Brushless DC motor, characterized in that the protruding base portion 34 is fitted to the frame of the power tool. The method of claim 1, Brushless DC motor, characterized in that for winding the coil (30) aligned with the bobbin (32). A stator 12 having n teeth 18 protruding from the cylindrical core bag 16 toward the inner circumference and having coils wound around the teeth 18, respectively; A brushless DC motor having a rotor 14 rotatably disposed on an inner circumferential side of the stator 12, The shaft hole 42 of the rotating shaft 50 penetrates in the axial direction of the center of the rotor core 40 of the rotor 14, At least a part of the cross section of the shaft hole 42 is substantially D-shaped, Brushless DC motor, characterized in that the cross-sectional shape of the rotating shaft (50) corresponding to the D-shaped shaft hole (42) is approximately D-shaped. The method of claim 4, wherein A plurality of magnet insertion holes 44 are formed in the axial direction of the rotor core 40, Rotating magnets 74 and 76 are inserted into the magnet insertion holes 44, respectively. A pair of cooling fans 52 and 54 are disposed at both ends of the rotor 14, And a rotating magnet (74, 76) inside each of said magnet insertion holes (44) by said pair of cooling fans (52, 54). The method of claim 4, wherein A ring-shaped position detecting magnet 64 is provided on one of the pair of cooling fans 52 and 54, A brushless DC motor, characterized in that a magnetic detecting element for detecting the rotational position of the rotor (14) is provided in the vicinity of the position detecting magnet (64). The method of claim 1, The cylindrical core bag (16) is a brushless DC motor, characterized in that formed by forming a cylindrical shape by caulking a ring-shaped steel sheet. The method of claim 1, The cylindrical core bag (16) is a brushless DC motor, characterized in that formed by integrally casting or pressing iron.

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