JPH07255157A - Synchronous motor - Google Patents

Abstract

PURPOSE:To provide a synchronous motor which does not result in enlargement of air gap, ensures strength against deterioration with time and does not allow separation of magnetic pole pieces by fixing magnetic pole pieces and permanent magnet with a clamping plate consisting of non-magnetic material which is inserted into a groove at the circumferencial end surface of each magnetic pole piece in a rotor and a side plate fixed at both end portions of the yoke. CONSTITUTION:A ring type permanent magnet 22, where S poles and N poles are arranged in the radial direction and the S poles and N poles are alternately arranged in the circumferencial direction, is provided at the external circumference section of a cylindrical yoke 21 consisting of a magnetic material. Moreover, six magnetic pole pieces 23 formed by laminating magnetic iron plates in the axial direction are provided at regular intervals at the external circumferencial section of the permanent magnet 22. The adjacent magnetic pole pieces 23 are pressed toward a yoke 21 with a clamping plate 24 consisting of non-magnetic material having a higher strength such as a stainless steel and both end portions or the clamping plate 24 are inserted into the cutout groove portion provided at the side plate 25 consisting of non-magnetic material having higher strength and thereby supported with the side plate 25. This side plate 25 is fixed by a continuous bolt 26 at both end portions of the yoke 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synchronous motor, and more particularly to the structure of a magnet type rotor.

[0002]

2. Description of the Related Art A synchronous motor is composed of a stator that generates a rotating magnetic field, a rotor that rotates, and a support for those rotors. The stator has slots inside, and an exciting coil is arranged in each slot. A rotating magnetic field is generated in the stator by the electric current from the power source, and a rotating force acts on the rotor by the rotating magnetic field, and the rotor rotates at a speed synchronized with the rotating force.

Regarding the structure of the rotor, for example, the actual development 6
3-138866.
This includes a cylindrical yoke 1 as shown in FIG.
It is attached to its outer peripheral portion and has an S pole and an N pole in the radial direction,
Further, it is composed of a ring-shaped permanent magnet 2 in which S poles and N poles are alternately arranged at equal intervals in the circumferential direction, and four magnetic pole pieces 3 arranged on the outer peripheral surface of the permanent magnet 2.

When the synchronous motor is driven, an attractive or repulsive force is generated between the rotating magnetic field of the stator and the magnet in the rotor, and the pole piece 3 in the rotating magnetic field is excited.
An attractive or repulsive force is applied to the generated magnetic poles, the force generated between the stator and the rotor is increased, and the operating efficiency and output are improved.

[0005]

However, the conventional magnet rotor as described above does not show a method for fixing the pole piece 3 to the permanent magnet 2. If it is fixed with an adhesive, peeling may occur due to centrifugal force during rotation of the rotor, inertial force during rapid acceleration / deceleration, etc., and peeling due to decrease in adhesive force due to heat generation and deterioration over time of the rotor. Further, when the outer peripheral surface of the magnetic pole piece 3 is wound and fixed with a band tape or the like, the air gap between the stator and the magnetic pole piece is widened due to the thickness of the band tape, which may worsen the efficiency and reduce the rotational torque. .

Although it is possible to perform integral molding with resin or the like, there is a problem that the permanent magnet is demagnetized when exposed to a high temperature environment for molding. Therefore, in view of the above conventional problems, it is an object of the present invention to provide a synchronous motor that does not widen the air gap and does not deteriorate with time.

[0006]

SUMMARY OF THE INVENTION According to the present invention, a cylindrical yoke concentrically connected to an output shaft, and an S pole and an N pole arranged in the radial direction on the outer peripheral surface of the yoke are arranged in the circumferential direction. A rotor including a ring-shaped permanent magnet having S poles and N poles alternately arranged, and a plurality of magnetic pole pieces provided on an outer peripheral surface of the permanent magnet, and a facing peripheral surface facing the outer peripheral surface of the rotor. In a synchronous motor including a stator having a plurality of opening slots formed therein, a concave groove or a shoulder extending in the output shaft direction is provided on a circumferential end surface of the magnetic pole piece, and non-magnetic push plates are adjacent to each other. The magnetic pole piece and the permanent magnet are inserted between the concave grooves or shoulders of the magnetic pole piece to press the magnetic pole piece and the permanent magnet toward the yoke side, and are supported by side plates fixed to both end portions of the yoke, so that the magnetic pole piece and the permanent magnet are supported. Is fixed to the yoke. It was assumed to be.

[0007]

In the rotor, the magnetic pole pieces and the permanent magnets are fixed to the yoke by the non-magnetic push plate that is passed through the groove or shoulder on the circumferential end surface of each magnetic pole piece and the side plates that are fixed to both ends of the yoke. Therefore, the air gap does not widen, the rotor is resistant to deterioration with time, and the pole piece is not peeled off. Furthermore, when the dimension from the outer diameter of the non-magnetic push plate and the side plate in the rotor to the facing surface of the stator is set to be twice the opening width of the opening slot, the non-magnetic push plate and the side plate are generated. Energy loss due to eddy current can be suppressed.

[0008]

FIG. 1 shows a first embodiment of the present invention.
The output shaft 10, the rotor 20, and the stator 30 are provided, an air gap 60 is provided between the rotor 20 and the stator 30 so that the rotor 20 can rotate, and opening slots 40 of equal pitch are provided on the inner peripheral surface of the stator 30. .

FIG. 2 shows the detailed structure of the rotor 20,
(A) is a side view and (b) is a sectional view. A ring-shaped permanent magnet 22 having S-poles and N-poles in the radial direction and alternating S-poles and N-poles in the circumferential direction is arranged on the outer periphery of a cylindrical yoke 21 made of a magnetic material. Six magnetic pole pieces 23 in which magnetic iron plates are laminated in the axial direction are provided at equal intervals on the outer peripheral portion of the magnet 22. A non-magnetic, high-strength push plate 24 such as stainless steel pushes each adjacent magnetic pole piece 23 toward the yoke 21 side, and both ends of the push plate 24 are provided on the side plate 25 also made of a non-magnetic, high-strength member. It is inserted into a notch groove and supported by the side plate 25. The side plate 25 is fixed to both ends of the yoke 21 with six through bolts 26.

FIG. 3 shows the pole piece 2 taken along the line AA of FIG.
3 is a cross-sectional view showing the structures of the push plate 3 and the push plate 24. FIG. Pole piece 23
A notch groove 27 extending in the axial direction is provided on the circumferential end face of the push plate 24, and the push plate 24 is inserted into the notch groove 27 of the adjacent magnetic pole piece so that the magnetic pole piece 23 and the permanent magnet 22 are connected to the yoke 21.
Push it to the side. FIG. 4A is a sectional view showing the structure of the rotor 20 and the stator 30 in the B section of FIG. (B) shows the CC cross section in (a). An exciting coil 50 is provided in an opening slot 40 having an opening width s. The rotor 20 sandwiches the air gap of δ1,
The distance δ2 from the push plate 24 to the inner peripheral surface of the stator 30 is set to be twice the opening width s of the slot 40 or more.

When driving the synchronous motor, by passing an alternating current through the coil 50 of the stator 30, the stator 30
A magnetomotive force is generated in the inside of the
A pole and an N pole are formed and serve as a rotating magnetic pole. An attractive or repulsive force is generated between this rotating magnetic pole and the N pole and S pole of the permanent magnet 22 in the rotor 20, and the magnetic pole piece 23 is excited. The attraction or repulsive force generated in the N pole and S pole thus formed is added to the driving force, and the electric motor is operated at a high output.

The magnitude of the eddy current generated by the periodic fluctuation of the magnetic flux density is proportional to the rotor coefficient Kc. Rotor coefficient K
c is calculated from the equation 1. The eddy current generated in the push plate is k
proportional to c-1.

[Equation 1] However, t: slot pitch, s: slot width, and δ: air gap.

FIG. 5 shows that t = 7 mm and s =
It is a calculated value of the coefficient Kc when 2.5 mm and δ are variable numbers. In FIG. 4, for example, the air gap δ1 is 1 m
m, and the rotor coefficient when the push plate 24 is provided on the outer peripheral surface of the rotor is kc1 = 1.12. On the other hand, the push plate 2
4 is the distance δ2 to the inner peripheral surface of the stator 30 and is the slot 4
When the opening width s of 0 is twice as large as 5 mm, the rotor coefficient is kc2 = 1.03. Therefore, in the latter case, the amount of eddy current generated by the push plate 24 is 1/4 of that in the former case, and the loss of electric energy on the push plate 24 due to the generation of the eddy current is 1/16 of that, which can be almost ignored. You can

FIG. 6 shows calculated values of the rotor coefficient kc when t = 15 mm and s = 3 mm. As in Figure 4,
When the air gap δ1 is 1 mm, the rotor coefficient kc1 is 1.08. When the distance δ2 between the pressing plate 24 and the inner peripheral surface of the stator 30 is twice the opening width s of the slot 40, which is 6 mm, the rotor coefficient kc2 = 1.02. Therefore, also in this case, the amount of eddy current generated by the push plate 24 is ¼ of the former amount, and the loss of electric energy can be almost ignored.

This embodiment is constructed as described above, and by using a non-magnetic high strength member such as stainless steel for the push plate 24 and the side plate 25, the induced magnetic force generated in the pole piece 23 is applied to the push plate 24 and the side plate. It is possible to more reliably fix the permanent magnet and the magnetic pole piece while preventing the leakage of the magnetic field to the drive unit 25 and the reduction of the driving efficiency. Further, even if a conductive material such as stainless steel is used for the push plate 24 and the side plate 25, the outer diameter dimension of the push plate 24 and the side plate 25 is separated from the opening width of the slot 40 of the stator 30 by twice or more. Since it is set to the position, the push plate 24
Also, the eddy current generated in the side plate 25 is greatly reduced to prevent the driving efficiency of the synchronous motor from being lowered. The magnetic pole pieces 23 are formed by laminating magnetic iron plates, and the generation of eddy currents is small.

FIG. 7 shows a modification of the magnetic pole piece pressing by the pressing plate taken along the line AA in FIG. In this example, the pole piece 23
A shoulder 28 extending in the axial direction is provided on the inner diameter side of the circumferential end surface of A, and the pressing plate 24 presses the shoulder 28 from the outer circumference of the adjacent magnetic pole pieces to fix the magnetic pole pieces 23A and the permanent magnet 22 to the yoke 21. And Both ends of the push plate 24 are inserted into the notch grooves of the side plate 25 and supported by the side plate 25. This also ensures that the pole pieces can be fixed.

FIG. 8 shows a second embodiment of the present invention.
(A) is a side view showing the detailed structure of the rotor 20, (b)
Is a sectional view. This embodiment is a rotor configured by using a yoke 21A and a side plate 25A instead of the yoke 21 and the side plate 25 of the first embodiment shown in FIG. The other structure is the same as that of the first embodiment. Shoulders are provided at both ends of the yoke 21A, and the side plates 25A are processed to fit into the shoulders. A ring-shaped permanent magnet 22 is arranged on the outer peripheral portion of the yoke 21A, and six magnetic pole pieces 23 are provided on the outer peripheral portion of the permanent magnet 22 at equal intervals. The push plate 24 pushes the adjacent magnetic pole pieces 23 toward the yoke 21A side, and the tip projection of the push plate 24 is inserted into the notch groove portion provided in the side plate 25A and supported by the side plate 25A. The side plate 25A is press-fitted or fixed to the shoulders of both ends of the yoke 21A with an adhesive or the like to form the rotor 20A. This embodiment is configured as described above, and since the side plate 25A and the yoke 21A are fixed by an adhesive or the like, there is no increase in the axial dimension due to the fixing bolts, and the synchronous motor is more compact than that of the first embodiment. Can be configured.

[0018]

As described above, according to the present invention, the magnetic pole pieces and the permanent magnets are yoked by the non-magnetic pressing plate that is passed through the groove or shoulder on the circumferential end surface of each magnetic pole piece and the side plates provided at both ends of the yoke. Since the magnetic pole pieces and the permanent magnets are fixed, the magnetic pole pieces and the permanent magnets can be reliably fixed. Therefore, the air gap does not widen, the rotor is resistant to deterioration over time, and the rotor without the pole piece peeling can be configured. As a result, a high-output, high-speed rotation synchronous motor can be constructed. Furthermore, when the dimension from the outer diameter of the non-magnetic push plate and the side plate in the rotor to the facing surface of the stator is set to be twice the opening width of the opening slot or more, the non-magnetic push plate and the side plate are generated. The energy loss due to the eddy current is suppressed, and the effect of high efficiency driving can be obtained.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a first exemplary embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a rotor unit of the first embodiment.

FIG. 3 is an enlarged cross-sectional view of a portion AA of FIG.

FIG. 4 is an enlarged view showing details of a portion B in FIG.

FIG. 5 is a calculation diagram of a rotor coefficient.

FIG. 6 is a calculation diagram of a rotor coefficient.

FIG. 7 is a diagram showing another modified example of FIG.

FIG. 8 is a diagram showing a configuration of a second exemplary embodiment of the present invention.

FIG. 9 is a diagram showing a configuration of a conventional example.

[Explanation of symbols]

 1, 21, 21A, yokes 2, 22, permanent magnets 3, 23, 23A, magnetic pole pieces 10, output shafts 20, 20A, rotor 24, push plates 25, 25A, side plates 26, bolts 27, notched grooves 28, shoulders 30, stator 40, slot 60, δ1, δ2 air gap S, opening width

Claims (2)

[Claims] 1. A cylindrical yoke concentrically coupled to an output shaft, and an S pole and an N pole arranged in the outer peripheral surface of the yoke in the radial direction and having the S pole and the N pole alternately in the circumferential direction. A rotor including aligned ring-shaped permanent magnets and a plurality of magnetic pole pieces provided on the outer peripheral surface of the permanent magnet, and a plurality of opening slots formed on the outer peripheral surface facing the outer peripheral surface of the rotor. In the synchronous motor including a stator, a concave groove or shoulder extending in the output shaft direction is provided on the circumferential end surface of the magnetic pole piece, and a non-magnetic push plate is provided between concave groove or shoulders of adjacent magnetic pole pieces. The magnetic pole piece and the permanent magnet are pressed against the yoke side, and are supported by side plates fixed to both ends of the yoke to fix the magnetic pole piece and the permanent magnet to the yoke. Characterized by being configured Synchronous motor. 2. The dimension from the outer diameter of the non-magnetic push plate or the side plate of the yoke to the inner peripheral surface of the stator is at least twice the opening width of the opening slot. The synchronous motor according to claim 1.