KR20070080931A - Linear motor - Google Patents

Abstract

A linear motor is provided to maximize a linear thrust generation efficiency of the linear motor by minimizing a size of an air gap by using an air gap controller. A linear motor supplies a linear thrust to a load and includes a rotor(10), a stator(20), and an air gap controller. The rotor is arranged to be parallel to a moving direction of a load(40). The stator is supported at a bottom of the load to form a predetermined air gap with the rotor. The stator generates a moving magnetic field. The air gap controller controls a position of the stator, so that the size of the air gap is maintained at a constant value. The air gap controller includes an air gap size sensor, a controller, and a displacement controller. The displacement controller vertical adjusts the position of the stator based on a control signal from the controller.

Description

Linear motor {Linear motor}

1 is a view schematically showing a configuration of a linear motor according to the prior art,

2 is a view schematically showing a linear motor configuration according to the present invention;

3 is a side view of the linear motor of FIG.

4 is a circuit diagram of the linear motor of FIG. 3, and

5 is a graph showing the efficiency of the driving force against the size of the void.

<Description of the symbols for the main parts of the drawings>

10: rotor 20: stator

30: air gap control unit 40: load

21: iron core 22: winding

31 controller 32 sensor

35: displacement controller 36: piezo motor

37: power amplifier 41: rail

42: wheels

The present invention relates to a linear motor for generating a linear propulsion force for moving a moving electric vehicle and a conveyor, and more particularly, to maximize the efficiency by maintaining and minimizing the size of the gap between the stator and the rotor to a predetermined size A linear motor that can be done.

BACKGROUND OF THE INVENTION In a production line, a logistics industry, or the like, a moving system including moving bodies such as a conveying vehicle moving a certain path is widely used in operations such as conveying an article or positioning an article. As a method of generating propulsion force for moving the moving body, a method of transmitting the rotating force generated from the rotating motor to the wheel of the moving body has been used, but its structure is complicated, noisy, frequent breakdown, and low propulsion efficiency. there was.

In order to solve the above problems, a linear motor having a relatively simple structure, fewer failures, and good propulsion efficiency is widely used.

Linear motors can be largely divided into linear induction motors and linear synchronous motors according to the arrangement of stators and rotors.

The linear induction motor is disposed in a load (electric vehicle) to which stators (iron cores and windings generating a moving magnetic field) move, and a rotor (aluminum plate) is disposed on a rail. Such a linear induction motor has the advantage of low construction cost, but the electromagnetic coil is installed in the vehicle has the disadvantage that the body is heavy, the noise is relatively high and the speed is not fast.

On the other hand, in a linear synchronous motor, a stator (electromagnet) is disposed on a rail, and a rotor (permanent magnet) is disposed on a load to which it moves. Such a linear synchronous motor has a large air gap because there is no exchange of electric power between the field and the armature, and the efficiency is good because there is no ending effect. Suitable for high speed use. However, there is a disadvantage in that the position signal for synchronization is required, and the electromagnetic coil must be installed over the entire rail, thereby increasing the construction cost and lowering the economic efficiency.

The linear induction motor and the linear motor are about 9 to 15 mm in size between the stator and the rotor due to shock and vibration during movement. The size of these voids had a problem of causing a decrease in the efficiency of the driving force.

Referring to Figure 1 will be briefly described the operation of the linear motor of the prior art. 1 is a view schematically showing the configuration of a linear motor according to the prior art. As shown, the rotor 10 is generally a plate made of aluminum and is installed on a track or road on which a vehicle travels. The stator 20 installed on the bottom surface of the load 40 at a predetermined distance from the rotor 10 includes a plurality of layers of iron cores 21 and a winding 22 in which coils are wound around the iron cores 21. . The moving magnetic field generated while the AC power of the predetermined frequency is supplied to the stator 20 is induced in the rotor 10, so that a driving force is generated between the stator 20 and the stator 20.

However, such a conventional linear motor has a problem that the efficiency of the propulsion force is lowered because the air gap (S) of a sufficient size does not interfere with the movement of the load 40 due to the bending of the line.

An object of the present invention is to solve the above problems, to provide a linear motor capable of maximizing the efficiency of the propulsion force by maintaining and minimizing the gap to a certain size in real time in response to changes in the road surface and high frequency vibration of the moving load. For the purpose of

The linear motor according to the present invention

A linear motor for supplying linear thrust force to a load, the linear motor comprising: a rotor disposed in parallel along a moving direction of the load; A stator that is supported on a bottom of the load to generate a moving field so as to form a predetermined gap against the rotor; And a pore control unit controlling the position of the stator such that the size of the pore maintains a preset value.

Preferably, the air gap control unit includes a sensor for detecting and outputting the size information of the air gap; A controller which receives the size information of the gap from the sensor and compares it with preset size information, and outputs a control signal for maintaining the gap at a preset value; And a displacement controller configured to vertically change a position of the stator supported by the load based on the control signal input from the controller.

In addition, the sensor is preferably any one of an ultrasonic sensor and an optical sensor.

Preferably the displacement controller comprises a piezoelectric motor for varying the displacement of the stator with respect to the load; And a power amplifier supplying power to the piezoelectric motor based on a control signal input from the controller.

Preferably, the position of the sensor with respect to the position of the piezoelectric motor is preferably spaced forward in the forward direction of the load by the distance that the load can move to the maximum during the reaction time of the piezoelectric motor.

The controller may be configured to delay the operation control signal outputted to the power amplifier based on the received speed information and output the variable speed information, wherein the delay time is inversely proportional to the moving speed of the load. .

Preferably, the controller receives the speed information at which the load moves, and outputs a control signal to the sensor to change the position of the sensor with respect to the position of the piezoelectric motor in the direction in which the load travels. The distance of the sensor relative to the position of the piezoelectric motor is proportional to the speed of the load.

In addition, the sensor is preferably provided with a transfer motor for varying the position of the sensor back and forth with respect to the traveling direction of the load based on the control signal input from the controller.

In addition, the one stator is preferably provided with the plurality of sensors and displacement controller.

In another embodiment of the present invention, the linear motor includes a linear motor for supplying a linear propulsion force to a load, the linear motor being disposed in parallel along a moving direction of the load to generate a moving magnetic field; A rotor which is supported on the bottom of the load to generate a magnetic field so as to form a predetermined gap facing the stator; And a pore control unit controlling the position of the rotor so that the size of the pore maintains a preset value.

Preferably, the air gap control unit includes a sensor for detecting and outputting the size information of the air gap; A controller which receives the size information of the gap from the sensor and compares it with preset size information, and outputs a control signal for maintaining the gap at a preset value; And a displacement controller configured to vertically change a position of the rotor supported by the load based on the control signal input from the controller.

Hereinafter, the operation of the linear motor according to the present invention will be described in more detail with reference to FIGS. 2 to 5.

Figure 2 is a schematic view showing the configuration of a linear motor according to the present invention, Figure 3 is a side view of the linear motor of Figure 2, Figure 4 is a circuit diagram of the linear motor of Figure 3, and Figure 5 is the driving force for the size of the air gap A graph showing the efficiency of the graph.

2 and 3 is an embodiment of a linear induction motor for moving a load (vehicle), such as an industrial conveyor running a designated trajectory.

The components of the present invention are largely supported on the rotor 10 disposed inside the rail 41 and the bottom of the load 40, and stators for generating a moving magnetic field with a gap of a predetermined distance from the rotor 10 ( 20) and the air gap control unit 30 for controlling the gap between the rotor 10 and the stator 20 at a predetermined interval.

The rotor 10 is a flat plate (plate) made of aluminum disposed inside the rail 41. The load 40 is guided by the rail 41 as a normal conveyor or electric vehicle, and moves along the rail 41 by wheels 42 provided at the lower end. On the bottom surface of the load 40, a stator 20 arranged to face each other with a predetermined gap between the rotor 10 is supported. The stator 20 is composed of an iron core 21 composed of a plurality of thin iron pieces and a winding 22 for generating a moving magnetic field in the iron core 21.

The stator 20 is supported on the bottom surface of the load 40. When the stator 20 is supplied with electric power in a state where a predetermined gap is formed with the rotor 10, a rotor magnetic field is generated. 10) is moved with the load 40 as a driving force to the repulsive force with the magnetic field induced by.

Meanwhile, as shown in FIG. 4, the air gap control unit 30 measures the air gap between the bottom of the stator 20 and the rotor 10 to output the size information of the air gap S, and the sensor ( The controller 31 outputs a control signal for comparing the size information of the pore output from the device 32 with the preset size information so that the measured pore size is maintained at the preset value, and the control signal output from the controller 31. It is provided with a displacement controller 35 for adjusting the vertical displacement of the stator 20 by moving the stator 20 up and down based on. The displacement controller 35 is fixed to interconnect the upper surface of the iron core 21 and the lower surface of the load 40, and is configured in a pair with the sensor 32 described above. Displacement controller 35 and the sensor 32 is provided with a total of four, one each in the left / right end of the front and the left / right end of the rear with respect to the traveling direction of the load 40. As shown in FIG. 4, the displacement controller 35 preferably uses a piezoelectric motor 32 and a power amplifier 37 for driving the displacement controller 35. Piezoelectric motor is a driving source that can obtain linear driving force and rotational force from ultrasonic vibration generated from piezoelectric ceramic element when voltage is applied. Therefore, the displacement controller 35 preferably uses a linear drive piezoelectric motor. The operating range of the linear-driven piezoelectric motor is not only a few Cm but also the reaction speed is very fast. Can react in real time and operate.

Unlike an electric vehicle driving on a road surface, the size of the air gap S of an industrial vehicle or an electric vehicle driving a designated trajectory generally has a size of about 9 mm. This is the minimum size in consideration of the up and down vibration and the flatness of the track accompanying the transport device.

However, when the present invention is used in an industrial vehicle or an electric vehicle that runs a designated trajectory, the size of the air gap S can be maintained at a minimum of 3 mm to maximize the propulsion force generation efficiency.

The characteristics of the propulsion force generation efficiency will be briefly described with reference to FIG. 5. 5 is a graph showing a change in efficiency with respect to the size of the air gap (S). As shown, the efficiency is about 50% when maintaining the air gap of 9mm in the industrial feeder using the linear motor as a driving force according to the prior art, the efficiency is about 70 when maintaining the air gap of 3mm by using the linear motor of the present invention It can be increased to about 20%, increasing the efficiency by about 20%.

On the other hand, in another embodiment of the present invention, considering the reaction time of the piezoelectric motor 36 and the maximum moving speed of the load 40, the sensor 32 of the piezoelectric motor 36 with respect to the traveling direction of the load 40 It may be placed in front of a distance that is more than adequate. That is, the position of the piezoelectric motor 36 and the position of the sensor 32 are spaced apart in the traveling direction of the load 40 by more than the maximum moving distance that the load 40 can move during the longest reaction time of the piezoelectric motor 36. . In this case, the controller 31 variably delays the operation control signal of the piezoelectric motor 36 in consideration of the speed of the load 40, and outputs the delay time in inverse proportion to the speed of the load 40. It may correspond in advance to the change in the gap (S) sensed by.

As another embodiment of the present invention, the position of the sensor 32 relative to the position of the piezoelectric motor 36 may be variably moved back and forth with respect to the moving direction of the load 40. That is, when viewed in a plane, the controller 31 of the sensor 32 is disposed so that the separation distance of the sensor 32 relative to the position of the piezoelectric motor 36 on the moving line of the load 40 is proportional to the speed of the load 40. To control the position. In this case, the sensor 32 is provided with a conveying motor (not shown) for conveying the position of the sensor 32. The controller 31 receives the speed information from which the load 40 moves from the outside (or a speedometer (not shown)), and considering the sensor, the controller (31) than the position of the piezoelectric motor (36) with respect to the traveling direction of the load (40). Output the control signal to the feed motor so that 32) is in front.

The embodiment of the present invention described above is limited to the process of controlling the air gap of the linear induction motor, but the case of the linear synchronous motor can be applied to the same process as described above. In the air gap control process of the linear synchronous motor, the process of controlling the air gap between the rotor 10 and the stator 20 in the structure in which the arrangement of the rotor 10 and the stator 20 are interchanged is the same as described above. Omit.

The technical idea of the present invention can be applied to various fields in which electric vehicles and other linear electric motors traveling on the road surface are utilized.

Specific embodiments shown and described in the accompanying drawings are only to be understood as an example of the present invention, not to limit the scope of the invention, but also within the scope of the technical spirit described in the present invention in the technical field to which the present invention belongs As various other changes may occur, it is obvious that the invention is not limited to the specific constructions and arrangements shown or described.

As described above, the present invention provides an effect capable of maximizing the driving force generated by maintaining and minimizing the gap to a certain size in real time in response to changes in the road surface and high frequency vibration of the moving load.

Claims (18)

In a linear motor that supplies linear thrust to the load, A rotor disposed in parallel along the moving direction of the load; A stator that is supported on a bottom of the load to generate a moving field so as to form a predetermined gap against the rotor; And And a pore controller for controlling the position of the stator such that the size of the pore maintains a predetermined value. The method of claim 1, wherein the air gap control unit A sensor for detecting and outputting size information of the gap; A controller which receives the size information of the gap from the sensor and compares it with preset size information, and outputs a control signal for maintaining the gap at a preset value; And And a displacement regulator for changing a position of the stator supported by the load up and down based on the control signal input from the controller. The method of claim 2, wherein the sensor Linear motor, characterized in that any one of an ultrasonic sensor and an optical sensor. According to any one of claims 2 to 3, wherein the displacement regulator A piezoelectric motor that varies the displacement of the stator with respect to the load; And And a power amplifier for supplying electric power to the piezoelectric motor based on a control signal input from the controller. The position of the sensor relative to the position of the piezoelectric motor is Linear motor, characterized in that spaced apart in the forward direction with respect to the traveling direction of the load by the distance that the load can move to the maximum during the reaction time of the piezoelectric motor. The method of claim 5, wherein the controller And a variable delay of an operation control signal outputted to the power amplifier based on the received speed information, and the delay time is inversely proportional to the moving speed of the load. The method of claim 4, wherein The controller receives the speed information at which the load moves, and outputs a control signal to the sensor to change the position of the sensor with respect to the position of the piezoelectric motor in the traveling direction of the load, based on the information. And the distance of the sensor relative to the position of the linear motor is proportional to the speed of the load. The method of claim 7, wherein And the sensor comprises a transfer motor for varying the position of the sensor back and forth with respect to the traveling direction of the load based on a control signal input from the controller. The method of claim 2, Wherein said one stator comprises said plurality of sensors and displacement controllers. In a linear motor that supplies linear thrust to the load, A stator arranged in parallel along the moving direction of the load to generate a moving magnetic field; A rotor which is supported on the bottom of the load to generate a magnetic field so as to form a predetermined gap facing the stator; And And a pore control unit controlling the position of the rotor so that the size of the pore maintains a predetermined value. The method of claim 10, wherein the air gap control unit A sensor for detecting and outputting size information of the gap; A controller which receives the size information of the gap from the sensor and compares it with preset size information, and outputs a control signal for maintaining the gap at a preset value; And And a displacement controller for changing a position of the rotor supported by the load up and down on the basis of the control signal input from the controller. The method of claim 11, wherein the sensor Linear motor, characterized in that any one of an ultrasonic sensor and an optical sensor. 13. The displacement controller according to any one of claims 11 to 12, wherein A piezoelectric motor that varies the displacement of the rotor with respect to the load; And And a power amplifier for supplying electric power to the piezoelectric motor based on a control signal input from the controller. The position of the sensor relative to the position of the piezoelectric motor is Linear motor, characterized in that spaced apart in the forward direction with respect to the traveling direction of the load by the distance that the load can move to the maximum during the reaction time of the piezoelectric motor. 15. The apparatus of claim 14, wherein the controller is And a variable delay of an operation control signal outputted to the power amplifier based on the received speed information, and the delay time is inversely proportional to the moving speed of the load. The method of claim 13, The controller receives the speed information at which the load moves, and outputs a control signal to the sensor to change the position of the sensor with respect to the position of the piezoelectric motor in the traveling direction of the load, based on the information. And the distance of the sensor relative to the position of the linear motor is proportional to the speed of the load. The method of claim 7, wherein And the sensor comprises a transfer motor for varying the position of the sensor back and forth with respect to the traveling direction of the load based on a control signal input from the controller. The method of claim 11, Wherein said one rotor comprises said plurality of sensors and displacement controllers.

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