JPH0817564B2 - Brushless motor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a brushless electric motor in which a stator is arranged on the outer circumference of a rotor, and more particularly to a brushless electric motor with an improved coil end treatment structure.

[Conventional technology]

This type of general brushless motor has rotor, stator,
It is composed of a housing, a bracket, a magnetic sensitive element and a drive circuit.

Specifically, the rotor is provided with a permanent magnet and a position detecting magnet whose opposite poles are alternately arranged in the circumferential direction on the rotor shaft. The stator surrounds the outer circumference of the rotor in a cylindrical shape,
A plurality of magnetic poles are projected toward the outer peripheral surface of the permanent magnet, and a coil is wound around each magnetic pole. The housing is
It has a substantially bottomed cylindrical shape, and a stator is fixed to its inner peripheral surface.

The bracket is interposed between the permanent magnet and the position detecting magnet and is attached to the opening of the housing. The magnetically sensitive element is arranged in the accommodating cylinder of the bracket so as to face the position detecting magnet. Then, the drive circuit receiving the detection signal of the magnetic sensitive element controls the energization of the coil to rotate the rotor.

The coil wound around each pole piece has a so-called Y connection in which one end corresponding to each phase is connected to the drive circuit and the other end is commonly connected. A general structure of the terminal processing of this coil will be described with reference to FIG.

This example is a three-phase drive and has six (6 poles) magnetic poles.
a1 to a6 are projected at equal intervals in the circumferential direction from the annular portion a of the stator A toward the permanent magnet (not shown) of the rotor, and the coils b1 to b6 are wound around them. There is. Therefore, the magnetic poles a1 and a4, a2 and a5, and a3 and a6, which are opposed to each other, have the same magnetic poles at the tip surfaces when the coils are energized. That is, coils b1 and b4, b2 and b5 corresponding to each phase,
One ends b1s, b3s, b5s of b3 and b6 are connected to a drive circuit (not shown), and the other ends b4e, b6e, b2e are commonly connected.

For this reason, the other end of the coil b1 and one end of the coil b4 are connected by a connecting wire w1, and the other end of the coil b3 and one end of the coil b6 are connected by a connecting wire w1.
w3 causes the other end of coil b5 and one end of coil b2 to crossover w5
Thus, the other ends of the coils b4, b6, b2 are connected to the common line w0. In addition, each one end b1s, b3s, b5s of the coil corresponding to each phase is cut to an appropriate length and connected to the lead wires S, T, U penetrating the bracket C, and thereby connected to the drive circuit. It

The stator A is fixed to the inner peripheral surface of the housing D having a substantially bottomed cylindrical shape by press fitting, and the bracket C is attached to the opening of the housing D.

[Problems to be Solved by the Invention]

2. Description of the Related Art In recent years, brushless electric motors have been widely used for OA equipment, FA equipment, household electric equipment such as electric tools, and the like. This is because, for example, when it is used for an electric power tool, there is a brush and a commutator, and thus there is a remarkable advantage that the life is dramatically extended and it does not become a source of noise and the like. For such a brushless electric motor, further miniaturization and higher output are strongly demanded.

Specifically, when it is used for an electric tool, for example, if the size is 46 mm in diameter and 68 mm in length, the maximum output
It is something like 200W. Moreover, if the power tool is rechargeable, a battery of about 10V must produce the above output, in which case a maximum current of 100A will flow through the coil. In other words, in order to meet the above requirements, one is that it is necessary to allow a large current to flow through the coil.

In order to pass such an electric current, the coil wire diameter is 1.
It is necessary to make it as thick as about 2 mm. With this wire diameter, it is possible to wind around the pole piece, but in the space formed by the housing and the bracket, the connecting work with the connecting wires w1, w3, w5 or common wire w0 as described above. Becomes extremely difficult.

Therefore, as shown in FIG. 7, all of one ends b1s to b6s and the other ends b1e to b6e of the coils b1 to b6 are made substantially straight to penetrate the bracket C, and these are provided outside the bracket C. A means for connecting the crossovers w1, w3, w5 formed in an arc shape or the common line w0 is conceivable.

However, if done in this way, all the ends of each coil b1 to b6 and the crossovers w1, w3, w5 or the common line w0 intersect with each other, and the connecting work is very troublesome. , It is also difficult to guarantee that the connection is secure.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a brushless electric motor capable of improving workability and reliability of terminal treatment of a coil.

[Means for solving the problem]

In order to solve such a problem, a brushless electric motor according to claim (1) includes a rotor, a stator around which a coil is wound,
Has a housing, a bracket, and a magnetically sensitive element,
A drive circuit that receives a detection signal from the magnetic sensitive element controls the energization of the coil to rotate the rotor,
In the brushless motor in which one end of the coil corresponding to each phase is connected to the drive circuit and the other end of the coil corresponding to each phase is commonly connected, the bracket has a terminal portion connecting the other end of the coil and It is composed of a wire connecting plate integrally formed with a connecting portion for connecting the terminal portions, and a bracket body made of an insulating material for fixing the wire connecting plate.

The brushless electric motor according to claim (2) is configured such that the bracket according to claim (1) is provided with a terminal plate having a terminal part for connecting one end of the coil and a terminal part for connection with a drive circuit. I am trying.

In the brushless electric motor according to claim (3), the terminal plate according to claim (2) is formed integrally with the connection plate and then cut so that an insulation gap is interposed therebetween. It has a certain structure.

In the brushless electric motor according to claim (4), the connection plate according to any one of claims (1) to (3) connects the terminal portion that connects the other end of the coil and the terminal portion that connects one end of the coil of the same phase. The crossover portion is integrally formed.

In the brushless electric motor according to claim (5), approximately half of the connecting portion of the connecting plate according to claim (4) in the circumferential direction is bent at a substantially right angle, and most of the portion is embedded in the bracket body. There is.

In the brushless electric motor according to claim 6, the bracket main body according to claim 4 or 5 is configured such that a housing cylinder portion surrounding the position detection magnet is formed so that each terminal portion is exposed. There is.

In the brushless electric motor according to claim (7), each of the terminal portions according to claims (1) to (6) is cut out in the radial direction, and the corresponding portion of the bracket body is also positioned in the radial direction. It has been cut out.

[Action]

In the brushless electric motor according to claim (1), since the other ends of the coils corresponding to the respective phases to be commonly connected are connected by a connecting plate that constitutes a bracket, the common wire required for the conventional ones. And the connection work with it becomes unnecessary.

In the brushless motor according to the second aspect of the present invention, both the one end of the coil and the lead wire for connection with the drive circuit may be connected to the terminal plate attached to the bracket. The work of directly connecting one end to the lead wire is unnecessary.

In the brushless motor according to claim (3), since the connection plate and the terminal plate can be formed as one component by press working, the number of components can be reduced and the molding process can be simplified.

The brushless electric motor according to claim (4) has a plurality of coils of the same phase, and even when a so-called crossover is required, the so-called crossover is connected by the crossover portion of the connecting plate, so that the conventional crossover is required. The wire and the connection work by it are unnecessary.

In the brushless electric motor according to claim (5), since the connecting portions of the connecting plates that originally intersect with each other are buried in the bracket body, the structure becomes simple as if it does not exist, and Can be surely protected.

In the brushless electric motor according to claim (6), since the connecting work between both ends of the coil and each terminal portion of the bracket main body can be performed outside the housing tubular portion after the bracket is attached to the housing, Work becomes easy.

In the brushless motor according to claim (7), the fitting work, which is a preparatory work for connecting both ends of the coil and each terminal portion of the bracket body, does not cause the holes to penetrate. Work becomes easy.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 5.

This brushless motor includes a rotor 1 provided with a permanent magnet 2 and a position detecting magnet 3, a stator 4 around which coils 5a to 5f are wound, a housing 6, a bracket 7, a magnetic sensitive element 11, and a drive circuit not shown. Is a main component.

In the rotor 1, a magnetic yoke 1b is press-fitted into the rotor shaft 1a, and a plurality of (for example, four) permanent magnets 2 segmented on the outer circumference of the magnetic yoke 1b are provided. In order to hold the permanent magnet 2 more firmly, a holding projection having a wide tip is projected from the outer peripheral surface of the magnetic yoke 1b, and the permanent magnet 2 is mounted in the space formed by the holding projection. The supporting side plates 1c are arranged on both sides and molded with the thermosetting resin 1d. As a result, the thermosetting resin 1d is filled in the through hole 1e of the magnetic yoke 1b or the gap between the permanent magnet 2 and the holding projection, and the permanent magnet 2 is firmly held. In the permanent magnet 2 thus provided, different poles are alternately located in the circumferential direction.

The position detecting magnet 3 is a rotary shaft 1a which is separated from the permanent magnet 2.
It is provided at one end portion of one side. This position detecting magnet 3 is
It has a ring plate shape and is adhered to the supporting disc 3a, and the supporting disc 3a is fixed to the rotor shaft 1a. Further, similarly to the permanent magnet 2, the poles are alternately located in the circumferential direction.

The stator 4 is formed by punching and laminating magnetic thin plates. The stator 4 surrounds the outer periphery of the rotor 1 in a cylindrical shape, and a plurality of (six in this embodiment) magnetic poles are arranged toward the outer peripheral surface of the permanent magnet 2.
4a to 4f are projected. The magnetic pole pieces 4a to 4f have a wide tip portion that serves as a magnetic pole. Then, the coils 5a to 5f are wound around the periphery of each of the magnetic pole pieces 4a to 4f except for the tip end portion through an insulating member.

Each coil 5a to 5f is wound with a thick element wire having a diameter of about 1.2 mm, and one end (for example, winding start side) 5as to 5fs and the other end (for example, winding end side) 5ae to 5fe thereof are parallel to the axis. It projects straight from the end surface of the stator 4.

The housing 6 has a substantially bottomed cylindrical shape and is provided with a bearing base 6c having a bearing 6b at the center of the bottom. On its inner surface,
A press-fitting projection 6d, a positioning portion 6e, a retaining portion 6f, etc. are formed, and the stator 4 is press-fitted and fixed by these.

The bracket 7 includes a bracket plate 8, a connection plate 9, and a bracket body 10. The bracket plate 8 is made of iron and has a center hole whose outer diameter is substantially equal to the inner diameter of the housing 6.
It has a disk shape having 8a. A bearing stand 8c having a bearing 8b is provided in the center hole 8a. Further, the bracket plate 8 has six small holes 8d and large holes 8e and twelve U-shaped grooves 8f formed by cutting the outside in the radial direction at substantially equal intervals in the circumferential direction. There is. This groove 8f is formed by each coil 5a to
One ends 5as to 5fs of 5f and the other ends 5ae to 5fe are inserted, and the positions are substantially corresponding to these.

The wire connection plate 9 is made of a conductive material such as copper having a thickness of about 0.5 mm, and is punched into the shape shown in FIG. A connecting portion 9g, which is a ring-shaped conductive path, is formed on the inner side, and further, three terminal portions 9be, 9de, 9fe projecting outward from the connecting portion 9g are formed integrally at approximately 120 ° intervals. are doing. This terminal part 9be, 9de, 9fe is the other end 5 of the coil corresponding to each phase.
It connects be, 5de, and 5fe, and a U-shaped groove is cut off in the radial direction near the center. This connection
The other ends 5be, 5de, 5fe of the coils corresponding to the respective phases are commonly connected by 9g and the three terminal portions 9be, 9de, 9fe.

Between these three terminal parts 9be, 9de, 9fe, 3 each
Individual terminal portions are formed. Now, add "s" to the terminal part connected to one end side of the coil and "e" to the terminal part connected to the other end side, and turn clockwise with reference to the terminal part 9be. , 9be, 9cs, 9ce, 9ds, 9de, 9es, 9ee, 9fs, 9fe, 9a
There will be 12 terminals in total, s, 9ae, 9bs.
All terminals are the same as the three terminals 9be, 9de, 9fe
A U-shaped groove is cut out in the vicinity of the center in the radial direction.

9ad, 9cd, 9ed are the terminal parts for connection with the drive circuit,
It is integrally formed by projecting outward from terminal portions 9as, 9cs, 9es connecting one ends 5as, 5cs, 5es of the coils corresponding to the respective phases. On the clockwise side of these terminal parts 9as, 9cs, 9es, the other ends 5ae, 5ce, 5e of adjacent coils connected via the connecting part T1.
From the terminal part 9ae, 9ce, 9ee connecting e, the terminal part 9ds, 9fs, 9bs connecting one end 5ds, 5fs, 5bs of the coil in phase with these
The crossover portions 9w, 9w, 9w for connecting and are integrally formed.
In each of the connecting portions 9w, approximately half 9wa in the circumferential direction is U-shaped, extends at the outermost position so as to straddle the two terminal portions, and the remaining approximately half 9wb has an arc shape. It extends so as to be sandwiched between the two terminal portions and the connecting portion 9g.
Further, the remaining half 9wb and the next two terminals are connected via the connecting portion T2, but there is a gap of about 1 mm between the other charging portion and the adjacent charging portion. In addition, crossing section 9
The two terminal portions that straddle about half the wa, which is the U shape of w, are also connected via the connecting portion T3.

The bracket body 10, together with the bracket plate 8 and the connection plate 9, is a portion made of an insulating material of the bracket 7 which is molded by simultaneous molding with a thermoplastic resin such as nylon 66. In this simultaneous molding, approximately half 9wa in the U-shaped circumferential direction of the crossover portion 9w is bent at a substantially right angle as shown in FIG. Then, the bracket plate 8 provided with the bearing base 8c and the connection plate 9 are mounted and molded in a molding die so that there is a slight gap therebetween.

The bracket body 10 molded in this way has a shape in which a gap between the bracket plate 8 and the connection plate 9 and six small holes 8d and large holes 8e are filled inward in the axial direction. In particular,
A thin portion connecting the holes is formed on the inner surface of the bracket plate 8 to securely fix the bracket plate 8 and the connection plate 9.
Further, at a position corresponding to the large hole 8e, a rod-shaped projection 10a extending to the vicinity of the end surface of the stator 4 is formed. Further, the portion corresponding to each terminal portion is also cut out radially outward.

On the other hand, in the axially outward direction, an accommodating cylinder portion 10c that surrounds the position detection magnet 3 is continuously provided together with an intermediate wall portion 10b that supports the bottom portion of the bearing base 8c. The accommodating cylinder portion 10c includes terminal portions 9as, 9ae, 9bs, 9be, 9cs, 9ce, 9ds, 9be, 9es, 9ee, 9fs, 9fe.
Is formed so as to expose. In addition, in the accommodating tubular portion 10c, approximately half 9wa in the U-shaped circumferential direction of the transition portion 9w is provided.
Most of the area is buried. Further, an attachment portion 10d for attaching the attachment plate 11a provided with the magnetically sensitive element 11 is formed on the end surface of the housing cylindrical portion 10c.

Such a bracket 7 has all the connecting portions T1, T2,
T3 is cut (at a portion indicated by a symbol X) so that a required insulation space is interposed between them. Then, before the position detecting magnet 3 is provided on the rotor shaft 1, the housing 6
Attach it to the opening. Specifically, the opening of the housing 6 and the bracket plate 8 are caulked. Therefore the bracket 7
Is interposed between the permanent magnet 2 and the position detecting magnet 3. And, one end 5as to 5fs and the other end 5a of the coil
The terminals e to 5fe are connected to the terminal portions 9as to 9fs and 9ae to 9fe, and the lead wires 7a connected to the drive circuit outside the drawing are connected to the terminal portions 9ad, 9cd, and 9ed, which have long projections, by soldering or the like.

The magnetic sensitive element 11 is, for example, a Hall element, and is attached to the mounting plate 11a so as to face the outer peripheral surface of the position detecting magnet 3.
It is provided in. When facing the N pole of the position detection magnet 3, this is detected and the signal is input to the drive circuit (not shown) via the lead wire 11b. Mounting plate 11a above
Has a substantially L shape, and is an attachment part of the bracket body 10.
It is screwed to 10d with a screw or the like.

In such a brushless electric motor, the detection signal of the magnetic sensitive element 11 is input to the drive circuit, and the drive circuit that operates controls the energization of the coil, whereby the rotor 1 rotates.

Regarding the terminal treatment of the coil, the workability and reliability are improved as follows. In other words, by connecting all ends of the coil to the terminals, there is no need to connect a common wire, a connecting wire, or a connecting wire to it, and the connecting parts and connecting parts instead of the common wire and the connecting wire are fixed members. The reliable insulation can be maintained. Above all, a crossover (a crossover) which originally intersects and becomes complicated can be embedded in the bracket body, so that workability and reliability are further enhanced.

Furthermore, the mounting of the coil to the terminal portions at both ends of the coil is extremely easy because the terminal portion is cut out radially outward. Moreover, since the terminal portions are located outside the accommodating cylinder portion, this can be easily connected to the terminal portions at both ends of the coil.

In addition, since the rod-shaped projection 10a of the bracket main body 10 extends to the vicinity of the end surface of the stator 4 as shown in FIG. 5, both ends of the coil protrude from the end surface of the pole piece 4a and come into contact with the rotor 1. Prevent that. If the rod-shaped protrusion 10a is not provided, as shown in FIG. 8, both ends of the coil may be out of the end faces of the magnetic pole pieces a1 to a6.

The present invention is not limited to those shown as the embodiments,
Various modifications can be made without departing from the spirit of the present invention.

First, when the bracket is constructed, the bracket plate is not an essential member and may be omitted. This is because the bracket plate is used in consideration of reinforcing the strength of the bracket and caulking the housing. Therefore, when this is omitted, the bracket body also has the function.

Further, if the connecting plate has three coils, the connecting portion is unnecessary. The terminal portion for connecting one end of the coil and the terminal portion for connection with the drive circuit may be attached to the bracket as a terminal plate separate from the connection plate.

Furthermore, if both ends of the substantially linear coil do not have a risk of protruding from the end faces of the magnetic pole pieces, the rod-shaped protrusion of the bracket body may be omitted.

〔The invention's effect〕

The brushless electric motor of the present invention described in claims (1) to (7) functions as described in the section [Operation]. Workability and reliability will be greatly improved.

[Brief description of drawings]

 FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention, FIG. 2 is a perspective view and an exploded view of a main part thereof, FIG. 3 is a perspective view of a main part of a coil end, and FIG. , A plan view of the connection plate, FIG. 5 is a partial perspective view showing a tip end portion of a rod-shaped projection, FIG. 6 is a perspective view of a main part showing an end of a conventional coil, and FIG. 7 is another conventional coil. FIG. 8 is a partial perspective view showing the terminal of FIG. 1 ... Rotor, 1a ... Rotor shaft, 1b ... Magnetic yoke, 2 ... Permanent magnet, 3 ... Position detection magnet, 4 ... Stator, 4a-4f ... Magnetic poles, 5a-5f …… Coil, 5as to 5fs …… One end, 5ae to 5fe …… The other end, 6 …… Housing, 7 …… Bracket, 7a …… Lead wire, 8 …… Bracket plate, 9 …… Wiring plate, 9g …… Connection part, 9w ... Crossover part, 9wa ... About half of U-shape, 9wb ... About half of arc shape, 9as ... to 9fs ... Terminal part to connect one end of coil, 9ae to 9fe ... Coil Terminal part for connecting the other end of 9d, 9cd, 9ed ...... Terminal part for connection with the drive circuit, T1, T2, T3 ...... connecting part, 10 ...... bracket body, 10a ...... rod-shaped projection, 10b ...... Intermediate wall, 10c …… Container cylinder, 11 …… Magnetic sensitive element, 11b …… Lead wire.

Claims (7)

[Claims] 1. A rotor having a rotor shaft provided with permanent magnets and position detecting magnets having different poles alternately arranged in the circumferential direction, and the outer periphery of the rotor is surrounded by a cylinder and the outer peripheral surface of the permanent magnet. A plurality of magnetic poles projecting toward each other and a coil wound around each magnetic pole; a housing having a substantially bottomed cylindrical shape and having the stator fixed to its inner peripheral surface; a permanent magnet; It has a bracket which is interposed between the position detecting magnet and attached to the opening of the housing, and a magnetic sensitive element arranged so as to face the position detecting magnet. The received drive circuit controls the energization of the coil to rotate the rotor, one end of the coil corresponding to each phase is connected to the drive circuit, and the other end of the coil corresponding to each phase is common. In a connected brushless motor, the bracket is A brushless electric motor comprising a terminal part for connecting the other end of the coil and a connecting plate integrally formed with a connecting part for connecting the terminal part, and a bracket body made of an insulating material for fixing the connecting plate. 2. The brushless electric motor according to claim 1, wherein the bracket is provided with a terminal plate having a terminal portion for connecting one end of the coil and a terminal portion for connection with a drive circuit. 3. The brushless electric motor according to claim 2, wherein the terminal plate is formed integrally with the connection plate and then cut so that an insulation gap is interposed between the terminal plate and the connection plate. 4. The connecting plate integrally forms a connecting portion that connects a terminal portion that connects the other end of the coil and a terminal portion that connects one end of the coil of the same phase. (3) The brushless electric motor according to item 3. 5. The brushless electric motor according to claim 4, wherein approximately half of the connecting portion of the connecting plate in the circumferential direction is bent at a substantially right angle, and most of the connecting portion is embedded in the bracket body. 6. The brushless electric motor according to claim 4, wherein the bracket body is formed so that a housing cylinder portion surrounding the position detecting magnet exposes each terminal portion. 7. The non-brush according to any one of claims 1 to 6, wherein each of the terminal portions is cut out in the radial direction and the corresponding portion of the bracket body is also cut in the radial direction. Electric motor.