JPH09200987A - Motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a motor capable of being rotated at low speed with high torque and having excellent controllability by forming a part or the whole of a rotor of a light weight material. SOLUTION: In a motor 20, a magnetic path is formed by coils LU1, LL1, a magnet M1 and a housing 22 formed by high permeability, and only the magnet M1 is used as a part forming the magnetic path in a rotor section 30. Consequently, the rotor section 30 (that is, a shaft 31 and a magnet holding section 32B integrally formed to the shaft 31) need not be formed of a heavy high- permeability material, the weight of the rotor section 30 can further be lightened by forming the rotor section of a light alloy, and the inertia of the rotor section 30 can be reduced by that amount. As a result, since controllability is not deteriorated even when the point of application, where drive power for rotating and driving the rotor section 30 is generated, is separated from the center of rotation of the shaft 31, the output torque of the shaft 31 can further be increased. Accordingly, the motor capable of being turned at low speed with high torque and having excellent controllability can be acquired.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of increasing the torque of a motor.

[0002]

2. Description of the Related Art Conventionally, so-called PM using a magnet
Some mold motors have a structure as shown in FIG. 11, for example. That is, in FIG. 11, 1 is P as a whole.
An M-type motor is shown, in which a rotating shaft 11 formed of a high magnetic permeability material such as iron-based metal is rotatably supported by a housing 3 of a stator portion 2 via a bearing 6.

A cylindrical magnet 12 is fixed to the rotating shaft 11 via a magnet holding member 13 made of a material having a high magnetic permeability so that it can rotate integrally with the rotating shaft 11. A laminated iron core 4 is provided on the inner side surface of the housing 3, and a winding 5 is wound around the laminated iron core 4 to form a coil 7. The coil 7 is arranged so as to face the outer peripheral surface of the magnet 12 with a predetermined gap.

Therefore, a magnetic path is formed through the magnet 12, the magnet holding member 13, the rotary shaft 11, the housing 3 and the coil 7, and the exciting coil is switched at a predetermined timing to sequentially generate a magnetic field in each exciting coil. Thus, the rotor portion 8 including the magnet 12 and the rotating shaft 11 can be driven to rotate.

[0005]

By the way, in order to rotationally drive the motor having such a structure with a high torque, it is necessary to increase the wire diameter of the winding wire 5 constituting each coil 7 to increase the current flowing therethrough. However, if the wire diameter is made thicker, the number of windings of the winding wound in a limited space must be reduced, and as a result, the number of rotations of the rotor portion 8 is inevitably increased in inverse proportion to the number of windings. However, there is an unavoidable problem that the rotation speed increases as the torque increases.

As one method for solving this problem, the diameter of the rotor portion 8 (that is, the magnet holding member 1)
3 and the diameter of the magnet 12), the distance from the center of rotation to the point of action of force can be increased to increase the output torque generated on the rotating shaft.

However, in general, the rotor portion 8 is made of a material having a relatively high weight such as a ferrous metal and having a high magnetic permeability, and the rotor portion 8 itself forms a part of a magnetic path. However, if the value is increased, there is a problem that the controllability is deteriorated, such as the inertia is increased and the start-up is delayed at the start, and the solution is still insufficient.

Further, in a stepping motor in which an iron piece is used as a rotor and rotor teeth and stator teeth are formed to perform a step operation of the rotor, when the rotor diameter is increased to increase the torque, the inertia of the rotor increases and a predetermined value is obtained. There is an unavoidable problem in that it is difficult to stop the rotor with the number of steps and the controllability deteriorates.

The present invention has been made in consideration of the above points, and it is an object of the present invention to propose a motor which can rotate at high speed and low speed and has good controllability.

[0010]

In order to solve the above problems, the motor according to the present invention employs the following means.

That is, according to the first aspect of the invention, in the motor including the stator and the rotor, a part or the whole of the rotor is formed of a lightweight material.

According to this means, the weight of the rotor can be reduced by forming the rotor with a lightweight material, and the inertia of the rotor becomes large even if the point of action of the force for generating the torque is moved away from the center of rotation. It can be effectively avoided. Therefore, the torque of the motor can be increased without impairing the controllability.

According to a second aspect, in the motor according to the first aspect, the lightweight material is a light alloy.

According to a third aspect of the present invention, in the motor of the first aspect, the lightweight material is a resin material.

According to a fourth aspect of the present invention, in the motor of the first aspect, the rotor has a rotating shaft and a magnet holding means, and the rotating shaft and the magnet holding means are formed of the lightweight material.

According to a fifth aspect of the invention, in the motor of the first aspect, the rotor has magnet holding means, and the magnet holding means is formed of the lightweight material.

According to a sixth aspect of the present invention, in a motor having a rotor provided with a magnet, the rotor has a plate-shaped magnet holding means having a thickness in a thrust direction and holding the magnet.

According to this means, the weight of the rotor can be reduced by forming the thin plate-shaped magnet holding means in the rotor in a flange shape with respect to the rotating shaft.
It is possible to effectively prevent the inertia of the rotor from increasing even if the action point of the force for generating the torque is moved away from the center of rotation. Therefore, the torque of the motor can be increased without impairing the controllability.

According to a seventh aspect of the invention, in the motor of the sixth aspect, the rotor has one of the magnet holding means, and the magnet holding means arranges the magnets concentrically with respect to a rotation center.

According to claim 8, in the motor of claim 6, the motor has a stator provided with a coil, the rotor has two magnet holding means, and the two magnet holding means are the magnet holding means. The coil of the stator is sandwiched with a predetermined gap from the thrust direction.

According to a ninth aspect of the present invention, in the motor of the sixth aspect, the magnet holding means has a support portion whose thickness decreases as the distance from the rotation center increases, and a magnet holding portion supported by the support portion. And a section.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a motor according to the present invention will be described below with reference to FIGS.

In FIG. 1, reference numeral 20 denotes a motor as a whole, and a stator portion 21 has a housing 22 made of a high magnetic permeability material, a bearing holding member 23, and a bearing 2
4 is held. The bearing 24 rotatably supports the rotating shaft 31 of the rotor portion 30 with respect to the stator portion 21.

The rotary shaft 31 is formed of a light alloy material such as duralumin, and the flange 32 is integrally formed of the same material as the rotary shaft 31 from the peripheral side surface thereof. The flange 32 has a supporting portion 32A and a thickness of the supporting portion 32A that decreases as the distance from the center of the rotating shaft 31 increases.
It is composed of a thin plate-shaped magnet holding portion 32B supported by the rotating shaft 31 by A.

The magnet holding portion 32B is shown in FIGS.
, A plurality of magnets M1 to Mx (in this embodiment, for example, 24 magnets M1 to M2
4) are arranged concentrically around the rotation center of the rotation shaft 31. Further, as shown in FIG. 1, in the housing 22 on the stator 21 side, a coil group LU and LL composed of a plurality of coils LU1 to LUx and LL1 to LLx in which conductive wires are wound around a coil bobbin 25 are magnet holding portions 32B of a flange 32. Is fixed to the housing 22 side by the caulking portion 32 so as to sandwich it with a slight gap.

As shown in FIG. 4, the coil group LU is centered on the rotation center of the rotation shaft 31 and the magnets M1 to M1.
For example, 20 coils LU1 to LU20 are arranged in a concentric circle shape having the same radius as in the case of the arrangement of M24.

The coil group LL (FIG. 1) is also similarly processed.
For example, 20 coils LL1 to LL20 are arranged concentrically around the rotation center of the rotation shaft 31 and having the same radius as in the case of the arrangement of the magnets M1 to M24.

Each coil LU1 to LU constituting the coil group LU1
The LU 20 has iron cores CU1 to CU20 in the center, and the coils LL1 to LL that form the coil group LL.
Similarly, 20 has iron cores CL1 to CL20 at the centers thereof.

Coils LU1 to L constituting the coil group LU
The iron cores CU1 to CU20 of U20 are the iron cores CL1 to CL2 of the coils LL1 to LL20 forming the coil group LL.
0 are arranged so as to face each other with a predetermined gap therebetween, and the magnet holding portion 32B is placed in this gap.
The magnets M1 to M24 held by are rotatably arranged with a slight gap from each iron core.

Thus, for example, the first coils LU1 and LL
When a drive current is applied to the cores 1, magnetic poles as shown in FIG. 1 are generated in the iron cores CU1 and CL1, respectively, whereby the iron core CL1, the housing 22, the iron core CU1 and the magnet M are generated.
1 forms a magnetic path.

FIG. 5 is a plan view showing the arrangement of the coils and magnets. The first coil CU is shown in FIG.
1st magnet M1 is opposed between 1 and CL1, 7th magnet M7 is opposed between 6th coil CU6 and CL6, 11th coil CU1
The 13th magnet M13 faces between 1 and CL 11, and the 16th coil CU 16 and CL 1
The sixteenth magnet M19 opposes between the six magnets.

As described above, four magnets of the 24 magnets M1 to M24 are always opposed to the 20 sets of coils arranged as a pair of coils (LUx, LLx) facing each other. It is done like this.

FIG. 6 shows a circuit for driving the motor 20 having such a structure. That is, reference numeral 40 in FIG. 6 denotes a motor drive circuit, and the drive unit 42 which is supplied with power from the power supply E rotates the motor 20 by sequentially supplying the drive current ID to each coil of the motor 20 at a predetermined timing.

That is, FIG. 7 shows the numbers of the excitation coils and the energization sequence when the motor 20 is rotated by the motor drive circuit 40. In the first excitation (primary excitation), the motor drive circuit 40 shows the first coil. LU1, L
L1 and the sixth coil LU6, LL6 and the eleventh coil LU11, LL11 and the sixteenth coil LU1
The four sets of coils are excited by supplying a drive current to 6 and LL16.

At this time, as shown in FIG. 5, the first magnet M1, the seventh magnet M7, the thirteenth magnet M13, and the nineteenth magnet M19 move to positions facing the respective exciting coils.

In the subsequent second excitation (secondary excitation), the motor drive circuit 40 drives the second coils LU2, L.
L2 and the seventh coil LU7, LL7 and the twelfth coil LU12, LL12 and the seventeenth coil LU1
The four sets of coils are excited by supplying a drive current to 7 and LL17.

At this time, as shown in FIG. 8, the second magnet M2 moves to a position facing the exciting coils LU2 and LL2, and the eighth magnet M8 moves to a position facing the exciting coils LU7 and LL7. , The 14th magnet M14 is the exciting coils LU12 and LL1.
2, and the 20th magnet M20 moves to a position facing the exciting coils LU17 and LL17.

In the subsequent third excitation (third excitation), the motor drive circuit 40 causes the third coil LU3, L3.
L3 and the eighth coil LU8, LL8 and the thirteenth coil LU13, LL13 and the eighteenth coil LU1
The four sets of coils are excited by supplying a drive current to 8 and LL18.

At this time, as shown in FIG. 9, the third magnet M3 moves to a position facing the exciting coils LU3 and LL3, and the ninth magnet M9 moves to a position facing the exciting coils LU8 and LL8. , The fifteenth magnet M15 is the exciting coils LU13 and LL1.
3, the 21st magnet M21 moves to a position facing the exciting coils LU18 and LL18.

By further moving four sets of exciting coils successively in the subsequent fourth-order excitation, fifth-order excitation, ..., The magnet holding portion 32B holding the magnets M1 to M24 is rotated, which causes the magnets. Holding part 3
The rotating shaft 31 formed integrally with 2B can be rotated.

Incidentally, as shown in FIG. 2, a plurality of through holes 36 are formed in the supporting portion 32A of the rotor portion 30, and the light from the light emitting portion 35A shown in FIG. It is designed to receive light.

Therefore, the light from the light emitting portion 35A is received by the light receiving portion 35B only when it passes through the through hole 36 due to the rotation of the rotor portion 30, and thereby an output having a frequency corresponding to the rotation speed of the rotor portion 30 is obtained. It is possible to control the rotation speed, the stop position and the like.

In the above configuration, the motor 20 has a configuration in which a magnetic path is formed by the coils LUx, LLx, the magnet Mx, and the housing 22 formed of a high magnetic permeability material, and the magnetic path is formed in the rotor portion 30. Only the magnet Mx is used as a component.

Therefore, it is not necessary to form the rotor portion 30 (that is, the rotating shaft 31 and the magnet holding portion 32B integrally formed with the rotating shaft 31) with a heavy and high magnetic permeability material. By forming the rotor portion 30 with a light alloy, the weight of the rotor portion 30 can be further reduced, and the inertia of the rotor portion 30 can be reduced accordingly.

Further, by forming the magnet holding portion 32B formed in the rotor portion 30 into a thin plate shape, the weight of the magnet holding portion 32B having the largest distance from the rotation center in the rotor portion 30 can be reduced. Therefore, the inertia of the rotor unit 30 can be reduced accordingly.

Therefore, even if the point of action (arrangement position of the magnets M1 to M24) where the driving force for rotationally driving the rotor portion 30 is generated is moved away from the rotation center of the rotation shaft 31, the rotation speed rises slowly at startup. There is no reduction in controllability.

Therefore, the magnets M1 to M24 are connected to the rotary shaft 3
By arranging the rotor 1 away from the center of rotation, the output torque of the rotary shaft 31 can be further increased without lowering the controllability when the rotor unit 30 is rotationally driven.

Incidentally, the magnet holding portion 32B formed in a thin plate is parallel to the rotating shaft 31 because it is supported by the rotating shaft 31 by the supporting portion 32A which gradually becomes thicker toward the center of rotation of the rotating shaft 31. The flexure in various thrust directions can be sufficiently reduced. Therefore, the magnet holding portion 32B (that is, the magnet Mx) and the coil LUx arranged so as to sandwich the magnet Mx,
The gap between the LLx and the iron cores CUx and CLx can be made sufficiently small, and the output torque of the rotating shaft 31 can be increased accordingly.

Further, in the motor 20 according to the present invention, the distance from the center of rotation to the point of action of force (arrangement position of magnet and coil) is replaced with the conventional method of increasing the amount of current to the coil to increase the torque. By using the method of increasing the torque generated in the rotary shaft 31 by increasing the torque, it is possible to prevent the rotation speed from unnecessarily increasing as the torque increases.

In addition, the rotor portion 30 is rotationally driven while always exciting four sets of 20 coils forming a pair with the magnet sandwiched from above and below, so that one set of coils is sequentially driven while being rotationally driven. It is possible to generate a torque that is four times that of the case. Thus, according to the above configuration, it is possible to obtain the motor 20 which can rotate at a low speed with a high torque and has good controllability.

In the above-described embodiment, the case where the rotor portion 30 is formed of an aluminum-based light alloy such as duralumin has been described, but the present invention is not limited to this.
For example, a magnesium-based light alloy such as electron or various other lightweight materials such as a lightweight resin material can be used to obtain the same effect as the above case.

Further, in the above embodiment, 24 magnets M1 to M24 and 20 sets of coils LU1 to L are provided.
The case of using U20 and LL1 to LL20 has been described, but the present invention is not limited to this, and various other numbers can be applied.

Further, in the above-described embodiment, the magnet holding portion 32 is provided by the support portion 32A whose thickness becomes smaller as the distance from the rotation center of the rotary shaft 31 becomes larger.
Although the case of supporting B has been described, the present invention is not limited to this, and a supporting portion having a constant thickness is formed between the rotating shaft 31 and the magnet holding portion 32B, or a supporting portion having a step is formed. You may do it.

In the above embodiment, the motor 20 having the structure in which the magnet Mx is sandwiched by the pair of coils LUx and LLx has been described, but the present invention is not limited to this.
A configuration may be used in which one coil is sandwiched by two magnets.

That is, in FIG. 10, reference numeral 50 denotes a motor according to another embodiment, in which a stator portion 51 is integrally formed with a housing 52 and a disk-shaped coil holding portion 56,
A rotor portion 60 is rotatably supported by the coil holding portion 56 via bearings 57A and 57B.

In the rotor portion 60, for example, a rotary shaft 65 made of a light alloy such as duralumin, and two flanges 61 and 62 are integrally formed on the rotary shaft 65 with the same material. The flanges 61 and 62 are arranged so as to sandwich the coil holding portion 56 of the stator portion 51 with a predetermined gap.

In the coil holding portion 56 of the stator portion 51, a plurality of coils 59 formed by winding the winding wire 53 around the laminated iron core 54 are arranged concentrically around the rotation center of the rotary shaft 65. Stator-side pole teeth 55A and 55B are provided on the upper and lower surfaces of the coil 59 so as to face the flanges 61 and 62, respectively.

Further, the flanges 61 and 62 of the rotor portion 60
In, the stator side pole teeth 5 provided on the stator side
Rotor-side pole teeth 63A and 63B are provided at positions facing 5A and 55B, respectively. Further, magnets MA and MB are fixed to the rotor side pole teeth 63A and 63B, respectively, so that the magnet MA, the rotor side pole teeth 63A, the stator side pole teeth 55A, the coil 59, the stator side pole teeth 55B, and the rotor side poles. Tooth 63B and magnet MB
A magnetic path is formed between them. Therefore, by supplying a drive current to each coil 59 at a predetermined timing, the flange 6
The rotor unit 60 including the rotary shafts 1, 62 and the rotary shaft 65 can be rotationally driven.

Also in this motor 50, the rotor portion 60 is formed of a lightweight material such as a light alloy as in the motor 20 described above with reference to FIG. 1, and the magnets MA and MB are attached to the thin plate-shaped flanges 61 and 62. By arranging the rotor unit 60, the rotor unit 60 can be further reduced in weight, and even if the magnets MA and MB are arranged away from the center of rotation by increasing the diameters of the flanges 61 and 62, the inertia of the rotor unit 60 increases. You can avoid that. Therefore, it is possible to obtain the motor 50 having a high torque and rotating at a low speed and having a good controllability.

Incidentally, a tap is formed at the center of the rotary shaft 65, and various members can be screwed together to transmit the rotary output. Further, a fixing tap 58 is formed on the outer peripheral surface of the housing 52 of the stator portion 51, so that the motor 50 can be screwed to various fixing objects such as a frame.

In the above-described embodiment, the case where the plurality of through holes 36 are formed in the support portion 32A has been described. However, the present invention is not limited to this, and other portions such as a part of the magnet holding portion 32B may be used. It may be formed at a position, and in this case, the light emitting portion and the light receiving portion may be arranged according to the position of the through hole. Further, instead of the through hole 36, a reflecting plate or a magnet may be used to reflect the detection light, or the magnetic sensor may detect the rotation state of the rotor unit 30.

Further, in the above-described embodiment, the case where the magnet holding portion 32B is sandwiched by the pair of coils LUx and LLx has been described, but the present invention is not limited to this, and one coil LUx or LLx may be used. The configuration may be such that it only faces the magnet holding portion 32B.

[0063]

As described above, in the motor according to the present invention, the weight of the rotor portion can be reduced by forming the thin plate-shaped magnet holding portion in the rotor portion into the flange shape with respect to the rotating shaft. Even if the action point of the force for generating the torque is moved away from the center of rotation, the inertia of the rotor portion can be effectively prevented from increasing. Therefore, the torque of the motor can be increased without impairing the controllability. Also, by forming the rotor part with a lightweight material, it is possible to reduce the weight of the rotor part, and it is effective that the inertia of the rotor part increases even if the point of action of the force for generating torque is moved away from the center of rotation. Can be avoided. Therefore, the torque of the motor can be increased without impairing the controllability. Further, by increasing the distance from the rotation center of the rotor portion to the point of action of force to increase the torque of the motor, it is possible to avoid an unnecessary increase in rotation speed.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a motor according to the present invention.

FIG. 2 is a perspective view showing an embodiment of a rotor unit according to the present invention.

FIG. 3 is a plan view showing an embodiment of a rotor unit according to the present invention.

FIG. 4 is a plan view showing an arrangement state of coils of a stator unit according to the present invention.

FIG. 5 is a schematic diagram showing an arrangement state of coils and magnets.

FIG. 6 is a connection diagram showing a motor drive circuit.

FIG. 7 is a chart showing a method of exciting a coil.

FIG. 8 is a schematic diagram showing an arrangement state of coils and magnets.

FIG. 9 is a schematic diagram showing an arrangement state of coils and magnets.

FIG. 10 is a sectional view showing another embodiment according to the present invention.

FIG. 11 is a sectional view showing a conventional motor.

[Explanation of symbols]

 20 Motor 21 Stator Part 22 Housing 30 Rotor Part 31 Rotating Shaft 32 Flange Part 32A Support Part 32B Magnet Holding Part LUx, LLx Coil Mx Magnet

Claims (9)

[Claims] 1. A motor comprising a stator and a rotor, wherein the rotor is partially or wholly made of a lightweight material. 2. The motor according to claim 1, wherein the lightweight material is a light alloy. 3. The motor according to claim 1, wherein the lightweight material is a resin material. 4. The motor according to claim 1, wherein the rotor has a rotating shaft and a magnet holding unit, and the rotating shaft and the magnet holding unit are formed of the lightweight material. 5. The motor according to claim 1, wherein the rotor has magnet holding means, and the magnet holding means is formed of the lightweight material. 6. A motor having a rotor provided with a magnet, wherein the rotor has a plate-like magnet holding means having a thickness in a thrust direction and holding the magnet. 7. The motor according to claim 6, wherein the rotor has one magnet holding means, and the magnets are arranged concentrically with respect to a rotation center by the magnet holding means. 8. The motor according to claim 6, wherein the motor has a stator provided with a coil, the rotor has two magnet holding means, and the two magnet holding means have coils of the stator. A motor characterized by being sandwiched with a predetermined gap from the thrust direction. 9. The motor according to claim 6, wherein the magnet holding means includes a support portion whose thickness decreases as the distance from the rotation center increases, and a magnet holding portion supported by the support portion. A motor that features