WO2019244209A1 - Stator for linear motor, linear motor, and linear motor system - Google Patents

Abstract

Provided is a stator (4) for a linear motor (1), which serves as a transport path for a mover (3) and which is provided with: first stator members (41) having permanent magnets (411) arranged in the direction of movement of the mover (3); and second stator members (42) comprising soft magnetic bodies and having magnetic flux guide sections (421) arranged in the direction of movement of the mover (4). The first stator members (41) and the second stator members (42) are arranged serially in the direction of movement of the mover (3).

Description

Linear motor stator, linear motor and linear motor system

The present invention relates to a linear motor stator serving as a moving path of a mover, a linear motor including a mover and a stator, and a linear motor system.

In recent years, linear motors that can perform direct linear motion instead of converting rotary motion to linear motion, and that can individually control multiple movable parts on the same transport path, have been applied to transport mechanisms. It is becoming. A transfer mechanism using a linear motor has been used in a wide variety of applications, such as application to a transfer mechanism between processes in a semiconductor device manufacturing process that requires removal of dust.

A linear motor generally has a mechanism in which a mover having a magnetic material and a winding drives on a stator. The stator serving as the transport path is configured by installing permanent magnets on the stator core by a method such as bonding. In such a motor configuration in which the magnets are arranged on the stator core, it is necessary to spread the magnets on the transport path, and the cost tends to increase. Also, magnets are used in a transport section that does not require acceleration / deceleration, that is, a transport section that does not require high thrust, and the specification is excessive.

The linear motor disclosed in Patent Literature 1 reduces the size of permanent magnets in an unnecessary range for a range in which high thrust is required, thereby making thrust appropriate and reducing cost by reducing the amount of magnets used. Has been implemented.

JP-A-11-332210

However, in the linear motor disclosed in Patent Document 1, although the amount of magnets used is reduced by reducing the size of the permanent magnets in a range where high thrust is unnecessary, the permanent magnets are provided on the entire stator serving as a conveyance path. Since the permanent magnet is used, the man-hour for installing the permanent magnet on the stator core is the same as that of a linear motor in which permanent magnets in a range where high thrust is unnecessary are not downsized. That is, the linear motor disclosed in Patent Literature 1 does not reduce the number of steps for installing permanent magnets on the stator core.

The present invention has been made in view of the above, and an object of the present invention is to provide a linear motor stator in which the number of steps for installing a permanent magnet on a stator core is reduced.

In order to solve the above-described problems and achieve the object, the present invention relates to a stator for a linear motor serving as a transfer path of a mover, the permanent motor having a permanent magnet arranged along the traveling direction of the mover. 1 stator member. The present invention includes a second stator member which is made of a soft magnetic material and has a magnetic flux guide disposed along the moving direction of the mover. The first stator member and the second stator member are arranged in series along the moving direction of the mover.

The stator of the linear motor according to the present invention has an effect that the number of steps for installing permanent magnets on the stator core can be reduced.

FIG. 1 is a diagram showing a configuration of a linear motor according to Embodiment 1 of the present invention. FIG. 1 is a diagram showing a configuration of a linear motor system using a linear motor according to a first embodiment. FIG. 4 is a diagram illustrating an example of a relationship between a moving speed of a mover of the linear motor according to the first embodiment and a position on a transport path. The figure which shows the thrust which a stator of the linear motor which concerns on Embodiment 1 produces to a mover. FIG. 7 is a diagram showing a modification of the linear motor according to the first embodiment. FIG. 4 is a diagram showing a configuration of a linear motor according to a second embodiment of the present invention. FIG. 7 is a diagram showing a configuration of a linear motor according to Embodiment 3 of the present invention. FIG. 7 is a diagram showing a configuration of a linear motor according to a fourth embodiment of the present invention. FIG. 14 is a diagram showing a configuration of a linear motor according to Embodiment 5 of the present invention. FIG. 14 is a diagram showing the phase of the linear motor according to the fifth embodiment. FIG. 17 is a diagram showing a relationship between the q-axis phase and the thrust with respect to the current of the linear motor according to the fifth embodiment. FIG. 17 shows a state where the phase difference between the current and the q-axis is 0 ° in the linear motor according to the fifth embodiment. The figure which shows the relationship between a d-axis and a q-axis, and a current in the state where the mover of the linear motor according to the fifth embodiment entered the second stator member. The figure which shows the structure which implement | achieved the function of the control apparatus which concerns on Embodiment 1 to Embodiment 5 with hardware. The figure which shows the structure which realized the function of the control apparatus which concerns on Embodiment 1 to Embodiment 5 with software.

Hereinafter, a stator of a linear motor, a linear motor, and a linear motor system according to an embodiment of the present invention will be described in detail with reference to the drawings. The present invention is not limited by the embodiment.

Embodiment 1 FIG.
FIG. 1 is a diagram showing a configuration of a linear motor according to Embodiment 1 of the present invention. The cross section shown in FIG. 1 is a cross section perpendicular to the gap G formed between the mover 3 and the stator 4 and parallel to the traveling direction A of the mover 3. The linear motor 1 drives a guide 5 extending in the traveling direction A, a slider 2 guided by the guide 5, a movable element 3 slidably supported in the traveling direction A by the slider 2, and a movable element 3. And a stator 4 to be used.

The mover 3 has a mover core 31 composed of a laminated core made of laminated soft magnetic materials. The mover core 31 has a plurality of teeth 312 protruding from the core back 311 to the gap G side. Further, the mover 3 has a winding 33 wound around a plurality of teeth 312. The winding 33 of the mover 3 shown in FIG. 1 is a concentrated winding that forms one coil for each tooth 312, but the winding 33 forms a coil across a plurality of teeth 312. It may be a distributed winding.

The mover 3 shown in FIG. 1 is an integrated type in which a core back 311 and a plurality of teeth 312 are integrated, but is divided into a plurality by the core back 311 and includes a plurality of core backs 311 and teeth 312. May be constituted by the divided cores. The mover 3 is not divided by the core back 311, and the core back 311 and the teeth 312 may be divided.

The stator 4 includes a first stator member 41 provided with a permanent magnet 411 and a second stator member 42 provided with a magnetic flux guide 421. The first stator member 41 and the second stator member 42 are arranged in series along the traveling direction A of the mover 3. In the first stator member 41, a plurality of permanent magnets 411 are provided at intervals on one surface of a first stator core 412, which is a magnetic yoke. The permanent magnet 411 is installed on the first stator core 412 in a state where the magnetization direction is oriented in the thickness direction of the first stator member 41. In the second stator member 42, a protrusion protruding from a second stator core 422, which is a soft magnetic yoke, forms a magnetic flux guide 421. Here, although a quadrangular projection is shown in FIG. 1, the shape of the projection may be an arc shape or a shape having a chamfer as long as the shape induces magnetic flux. The first stator member 41 is arranged with the side on which the permanent magnet 411 is installed facing the gap G. The second stator member 42 is disposed with the side on which the magnetic flux guide 421 is formed facing the gap G. Therefore, when the mover 3 passes over the first stator member 41, the first stator member 41 and the mover 3 constitute a permanent magnet motor. On the other hand, when the mover 3 passes over the second stator member 42, the second stator member 42 and the mover 3 constitute a synchronous reluctance motor.

FIG. 2 is a diagram showing a configuration of a linear motor system using the linear motor according to the first embodiment. The linear motor system 50 receives an inverter 70 that converts the frequency of the power supplied from the power supply 60 and supplies the same to the linear motor 1, and a current value of the power supplied to the linear motor 1 by the inverter 70, and converts the voltage command into an inverter. And a control device 80 for outputting to the control unit 70. The control device 80 controls the moving direction and the moving speed of the mover 3.

In the range where the synchronous reluctance motor is configured, the second stator member 42 in which the magnetic flux guide 421 is formed in the second stator core 422 and the movable member that generates a magnetic field by passing a current through the winding 33. A thrust is generated in the mover 3 using the reluctance force between the mover 3 and the armature 3. Synchronous reluctance motors have a configuration in which the magnetic resistance varies depending on the position of the mover in the moving direction.The synchronous reluctance motor is a motor that generates thrust using reluctance force generated in the direction in which the magnetic resistance decreases, without using permanent magnets. Thrust can be generated. In the synchronous reluctance motor, thrust is generated due to the difference Ld-Lq between the d-axis inductance Ld and the q-axis inductance Lq, and Ld ≠ Lq.

When the relationship between the d-axis inductance Ld and the q-axis inductance Lq is Ld ≠ Lq, there is a position dependency of the inductance known as saliency. In the range in which the synchronous reluctance motor is configured, the control device 80 estimates the position of the mover 3 in the traveling direction using the saliency, and uses the estimated position to adjust the current in accordance with the phase of the magnetic pole. Control, speed control of the mover 3, or position control of the mover 3 is performed. Performing current control, speed control of the mover 3, or position control of the mover 3 using the estimated position in accordance with the phase of the magnetic pole is also referred to as sensorless driving. When performing sensorless driving, the control device 80 performs current control, speed control of the mover 3, or position control of the mover 3 in accordance with the phase of the magnetic pole without using the position detector and the speed detector. . The control device 80 uses the speed, which is a differential component of the estimated position, in addition to the estimated position of the mover 3 in the traveling direction, to control the current in accordance with the phase of the magnetic pole, to control the speed of the mover 3, or The position of the mover 3 may be controlled. In the method of estimating the position of the mover 3 using saliency, a high-frequency voltage command for position estimation is added to the voltage command for current control and output to the inverter 70, and the detected current is used to determine the inductance Ld and Lq. A method of estimating the salient pole ratio Lq / Ld and estimating the position of the mover 3 from the estimated value of the salient pole ratio Lq / Ld can be exemplified, but the method is not limited thereto.

On the other hand, in a range in which the permanent magnet motor is configured, the control device 80 may drive the mover 3 sensorlessly, or may drive the mover 3 based on a detection result of a sensor that detects the position of the mover 3. May be.

The controller 80 drives the mover 3 sensorlessly on the second stator member 42, so that there is no need to install a sensor for detecting the position of the mover 3 in a range where the synchronous reluctance motor is configured. The linear motor system 50 can be simplified.

FIG. 3 is a diagram illustrating an example of a relationship between a moving speed of the mover of the linear motor according to the first embodiment and a position on the transport path. When the mover 3 moves from the position x0 to the position x3, the mover 3 accelerates between the positions x0 and x1, and moves at a constant speed between the positions x1 and x2. The mover 3 decelerates between the position x3 and the position x3.

When the linear motor 1 according to the first embodiment is used as the power source of the transfer device, in order to improve the tact time, it is necessary to increase the upper limit of the moving speed of the mover 3 or to increase or decrease the speed of the mover 3. It is necessary to increase the acceleration.

When the acceleration at the time of accelerating or decelerating the mover 3 is a [m / s], the thrust is F [N], and the mass of the work carried by the mover 3 and the mover 3 is m [kg]. , The following equation (1) holds.

{F = ma} (1)

From equation (1), it can be seen that if the mass m is the same, the thrust F needs to be increased in order to increase the acceleration a.

By the way, between the position x1 and the position x2, the mover 3 moves at a constant speed. Therefore, theoretically, it is not necessary to generate a thrust between the position x1 and the position x2, but actually, a negative acceleration is generated due to the friction between the slider 2 and the guide 5 and the air resistance. It is necessary to generate a certain amount of thrust to cancel the resistance. The thrust required to maintain the constant speed motion of the mover 3 is smaller than the thrust at the time of acceleration and deceleration.

FIG. 4 is an explanatory diagram of thrust generated by the stator of the linear motor according to the first embodiment on the mover. FIG. 4 shows the results of obtaining the thrust generated by the first stator member 41 and the thrust generated by the second stator member 42 by magnetic field analysis. In FIG. 4, the thrust generated by the first stator member 41 on the mover 3 is normalized to be 1. The thrust generated by the second stator member 42 on the mover 3 is 10% or more and less than 20% of the thrust generated by the first stator member 41 on the mover 3. That is, the absolute value of the acceleration generated by the first stator member 41 on the mover 3 in the section in which the first stator member 41 is disposed is equal to the absolute value of the acceleration in the section in which the second stator member 42 is disposed. Is greater than the absolute value of the acceleration generated by the stator 3 of the mover 3.

The linear motor 1 according to the first embodiment includes a position between the position x0 and the position x1, which is a section for accelerating the mover 3, and a position between the position x2 and the position x3, which is a section for decelerating the mover 3. One stator member 41 is arranged. Further, in the linear motor 1 according to the first embodiment, the second stator member 42 is disposed between the position x1 and the position x2, which is a section where the mover 3 moves at a constant speed.

In the section between the position x0 and the position x1 where the first stator member 41 is arranged and in the section between the position x2 and the position x3, a large thrust is generated on the mover 3 and a large acceleration can be obtained. . Further, in the section between the position x1 and the position x2, in the case of the slider 2 used for a normal linear motor, the dynamic friction coefficient μ is between 0.002 and 0.003, and the seal resistance f is between 2N and 5N. Between. Therefore, when the load W applied to the slider 2 is 3000N, the frictional resistance F 'is calculated to be about 13N from the following equation (2).

{F ′ = μW + f} (2)

When the load applied to the slider 2 is 3000N, the thrust generated by the first stator member 41 is 200N. As shown in FIG. 4, the thrust generated by the second stator member 42 is 10% or more of the thrust generated by the first stator member 41, and is therefore 20N or more. Since the thrust generated by the second stator member 42 is larger than the frictional resistance F ′ at the time of constant velocity movement, the second stator member 42 has a thrust capable of moving the mover 3 at constant velocity. It can be seen that this is occurring.

As described above, in the stator 4 of the linear motor 1 according to the first embodiment, the first stator member 41 is disposed in a section where the mover 3 is accelerated or decelerated, and the mover 3 is moved at a constant speed. Since the second stator member 42 is arranged in the section, the usage amount of the permanent magnet 411 in the entire stator 4 can be reduced without impairing the acceleration / deceleration performance of the mover 3. That is, the device maker that manufactures the linear motor 1 arranges the first stator member 41 in the section where the mover 3 is accelerated and decelerated in accordance with the driving operation pattern of the mover 3 and accelerates and decelerates the mover 3. By assembling the stator 4 by arranging the second stator member 42 in a section where it is not necessary to perform the operation, the usage amount of the permanent magnet 411 in the entire stator 4 can be reduced without impairing the acceleration / deceleration performance of the mover 3. Reduce.

In FIG. 1, the number of permanent magnets 411 facing the mover 3 is the so-called 4-pole, 6-slot linear motor 1 in which the number of permanent magnets 411 is 4 with respect to the number 6 of teeth 312. May be combined with the number of poles and the number of slots.

FIG. 5 is a diagram showing a modification of the linear motor according to the first embodiment. The magnetic flux guiding portion 421 of the second stator member 42 shown in FIG. 1 is formed by a projection projecting from the second stator core 422 into the gap G, but as shown in FIG. By providing the slit holes 425 in the stator core 422, the magnetic flux guide 421 can be formed. In FIG. 5, the magnetic flux guiding portion 421 is formed by an arc-shaped slit hole 425, but the slit hole 425 forming the magnetic flux guiding portion 421 only needs to have a shape that generates reluctance torque, and is limited to an arc shape. Not done.

The linear motor 1 according to the first embodiment includes a first stator member 41 having a permanent magnet 411 and a second stator member 42 having a magnetic flux guide 421 formed of a soft magnetic material. With this configuration, a high thrust is generated in the first stator member 41, smooth start and stop by high acceleration / deceleration are possible, and in the drive range requiring constant-velocity motion, the magnetic flux guiding portion 421 The second stator member 42 having the above-described configuration generates a thrust that can move at a constant speed using the reluctance torque generated by the magnetic flux guide 421 without using the permanent magnet 411. Providing the two different stator members in this way makes it possible to optimize thrust specifications and reduce the amount of magnets used. Further, since it is unnecessary to install the permanent magnet 411 on the second stator core 422, the man-hour for magnetizing the permanent magnet 411 and the man-hour for installing the permanent magnet 411 on the iron core of the stator 4 are reduced. Can be reduced.

Embodiment 2 FIG.
FIG. 6 is a diagram showing a configuration of a linear motor according to Embodiment 2 of the present invention. The cross section shown in FIG. 6 is a cross section perpendicular to the gap G formed between the mover 3 and the stator 4 and parallel to the traveling direction A of the mover 3. The second stator member 42 of the linear motor 1 according to the second embodiment has a so-called consequent type in which permanent magnets 411 are arranged between the magnetic flux guides 421 at both ends in the traveling direction. This is different from the second stator member 42 of the first embodiment. The portion of the second stator member 42 where the permanent magnet 411 is sandwiched between the magnetic flux guides 421 is called a consequent unit 423. The permanent magnet 411 is installed on the second stator core 422 such that the magnetization direction is oriented in the thickness direction of the second stator member 42.

When moving from the first stator member 41 to the second stator member 42, the mover 3 is driven in the opposite direction to the driving direction by the magnetic attraction of the permanent magnet 411 disposed on the first stator member 41. Force may be applied, and the speed may decrease. In order to attenuate the magnetic attraction force of the first stator member 41 by the permanent magnet 411 and allow the mover 3 to smoothly enter from the first stator member 41 to the second stator member 42, It is necessary to reduce the magnetic flux generated from the element 4 to the gap G.

Generally, in a consequent type motor, the magnetic flux generated in the air gap is reduced from 50% to 70% as compared with the magnetic flux generated from a stator constituted only by permanent magnets. Therefore, the magnetic attractive force of the permanent magnet 411 is reduced on the consequent part 423. Further, the thrust on the consequent portion 423 is 50% or more as compared with the thrust generated on the first stator member 41 in which only the permanent magnet 411 generates the thrust. Therefore, even if the mover 3 enters the consequent portion 423 of the second stator member 42 from the first stator member 41, the speed is hardly attenuated by the magnetic attraction force.

Further, by providing a consequent portion 423 between the permanent magnet 411 of the first stator member 41 and the magnetic flux guide portion 421 group of the second stator member 42, the first stator member 41 Since the magnetic attraction force changes stepwise with the second stator member 42, the mover 3 traveling from the consequent portion 423 to the group of the magnetic flux guide portions 421 on the second stator member 42 has a thrust force. The speed is hardly attenuated even if is reduced, and a smooth movement is possible.

In the above description, the mover 3 has advanced from the first stator member 41 to the second stator member 42, but has advanced from the second stator member 42 to the first stator member 41. Also in this case, the mover 3 can be moved smoothly by increasing the thrust stepwise.

In the linear motor 1 according to the second embodiment, since the permanent magnet 411 is not disposed at the center of the second stator core 422, the number of steps for installing the permanent magnet 411 on the stator core can be reduced.

Embodiment 3 FIG.
FIG. 7 is a diagram showing a configuration of a linear motor according to Embodiment 3 of the present invention. The cross section shown in FIG. 7 is a cross section perpendicular to the gap G formed between the mover 3 and the stator 4 and parallel to the traveling direction A of the mover 3. The second stator member 42 of the linear motor 1 according to the third embodiment has permanent magnets 411 disposed at both ends in the traveling direction A, and is formed of a soft magnetic material at the center in the traveling direction A. It has a magnetic flux guide 421. The portion of the second stator member 42 where the permanent magnet 411 is arranged is referred to as a magnet installation part 424. The permanent magnet 411 is installed on the second stator core 422 such that the magnetization direction is oriented in the thickness direction of the second stator member 42. The permanent magnet 411 arranged on the magnet mounting portion 424 of the second stator member 42 of the linear motor 1 according to Embodiment 3 has a smaller size than the permanent magnet 411 of the first stator member 41, or The residual magnetic flux density is small. When the permanent magnet 411 smaller than the permanent magnet 411 of the first stator member 41 is disposed on the second stator member 42, the residual magnetic flux density of the permanent magnet 411 increases as approaching the first stator member 41. You may make it become.

When the mover 3 enters the second stator member 42 from the first stator member 41, the mover 3 is decelerated by the magnetic attraction force of the permanent magnet 411 of the first stator member 41, and a smooth drive is performed. May not be possible. In order to enable smooth driving, it is necessary to reduce the magnetic flux generated in the gap G stepwise.

(4) The magnetic flux generated by the permanent magnet 411 decreases as the magnetized area decreases. That is, the permanent magnet 411 has a dimension perpendicular to the traveling direction of the mover 3 and from the stator 4 toward the mover 3 or a direction perpendicular to the traveling direction of the mover 3 and traveling from the stator 4 to the mover 3 side. When the dimension in the direction perpendicular to the direction becomes smaller, the magnet width becomes shorter, and the magnetic flux generated by the permanent magnet 411 decreases. Also, it is generally known that the operating point is lowered and the magnetic flux density is reduced by reducing the size of the permanent magnet 411 in the direction perpendicular to the moving direction of the mover 3 and in the direction from the stator 4 to the mover 3 side. ing. In addition, when the residual magnetic flux density decreases, the generated magnetic flux decreases.

磁石 A magnet smaller in size than the permanent magnet 411 of the first stator member 41 or a permanent magnet 411 having a small residual magnetic flux density is used for the magnet mounting portion 424 of the linear motor 1 according to the third embodiment. Accordingly, the magnetic flux generated in the air gap G is reduced, and the magnetic attraction force is reduced stepwise when the mover 3 enters the second stator member 42 from the first stator member 41, thereby reducing the first fixed state. It is possible to eliminate the attenuation of the speed of the mover 3 due to the entry from the slave member 41 to the second stator member 42, and to smooth the drive.

Embodiment 4 FIG.
FIG. 8 is a diagram showing a configuration of a linear motor according to Embodiment 4 of the present invention. The cross section shown in FIG. 8 is a cross section perpendicular to the gap G formed between the mover 3 and the stator 4 and parallel to the traveling direction A of the mover 3. The surface of the first stator member 41 on the gap G side where the magnetic flux is generated and the surface of the magnetic flux guide portion 421 formed on the second stator member 42 on the gap G side are defined as magnetic pole surfaces 413 and 426, respectively. . When the first stator member 41 and the mover 3 face each other, the distance G1 between the magnetic pole surface 413 of the first stator member 41 and the mover 3 is equal to the distance G1 between the second stator member 42 and the mover 3. 3 is greater than or equal to the distance G2 between the magnetic pole surface 426 of the second stator member 42 and the mover 3 when they face each other. By setting G1 ≧ G2, when the mover 3 passes through the boundary between the first stator member 41 and the second stator member 42, a rapid change in thrust is suppressed, and the mover 3 is moved. It can be moved smoothly.

In the linear motor 1 according to the fourth embodiment, the distance G2 between the magnetic pole surface 426 of the second stator member 42 and the mover 3 increases as approaching the first stator member 41. By increasing the distance G2 as approaching the first stator member 41, the thrust changes stepwise at the boundary between the first stator member 41 and the second stator member 42, and The effect of moving the child 3 smoothly can be enhanced. Therefore, as in the case of the linear motor 1 according to the third embodiment, the speed of the mover 3 is not attenuated due to the entry from the first stator member 41 to the second stator member 42, and the driving is smoothed. Is possible. However, the distance G2 between the magnetic pole surface 426 of the second stator member 42 and the mover 3 may be constant.

Embodiment 5 FIG.
FIG. 9 is a diagram showing a configuration of a linear motor according to Embodiment 5 of the present invention. The cross section shown in FIG. 9 is a cross section perpendicular to the gap G formed between the mover 3 and the stator 4 and parallel to the traveling direction A of the mover 3. In the first stator member 41 and the second stator member 42 constituting the stator 4 of the linear motor 1 according to the fifth embodiment, the first stator member 41 and the second stator member 42 are formed by the permanent magnets 411 arranged on the first stator member 41. The magnetic pole faces 413 are arranged on the first stator core 412 at a pole pitch τp along the traveling direction A. In FIG. 9, the second stator member 42 has a so-called surface magnet type configuration in which a permanent magnet 411 is disposed on the surface of the first stator core 412 on the mover 3 side. However, an embedded magnet type in which a permanent magnet 411 is embedded in the first stator core 412 may be used. Further, the configuration may be such that the magnetization direction of the permanent magnet 411 is parallel to the traveling direction A and the magnetization directions are opposed to each other. Further, the second stator member 42 may have a hull-back type structure.

The second stator member 42 includes only a magnetic flux guide 421 formed of a second stator core 422 and a soft magnetic material formed on the second stator core 422, and includes a permanent magnet 411. Is not located. The magnetic flux guide 421 may be formed by the slit holes 425 as described in the second embodiment.

は In the first stator member 41, the distance between the centers of the adjacent magnetic pole faces 413 is τp. In the second stator member 42, the center-to-center distance between adjacent magnetic pole surfaces 426 is l.

The center between the center of the magnetic pole surface of the first stator member 41 and the center of the magnetic pole surface of the second stator member 42 which are adjacent to each other via a connection portion between the first stator member 41 and the second stator member 42. Is L. The distance L is τp / 2 + (n−1) τp ≦ L ≦ nτp. Here, n is a natural number of 1 or more.

In FIG. 9, the center of the pole face 413 of the first stator member 41 is the d-axis, and the middle of the adjacent pole face 413 is the q-axis. Similarly, the center of the magnetic pole surface 426 of the second stator member 42 is the d-axis, and the middle between adjacent magnetic pole surfaces 426 is the q-axis. FIG. 10 is a diagram illustrating phases of the linear motor according to the fifth embodiment. As shown in FIG. 10, the angle between the current i flowing through the coil and the q axis is defined as a phase difference θ. FIG. 11 is a diagram illustrating the relationship between the q-axis phase and the thrust with respect to the current of the linear motor according to the fifth embodiment. The thrust generated by the first stator member 41 indicated by a solid line in FIG. 11 is a value normalized so that the peak value of the thrust generated by the first stator member 41 becomes 1. Further, the thrust generated by the second stator member 42 indicated by the broken line in FIG. 11 is a value normalized such that the peak value of the thrust generated by the second stator member 42 becomes 1.

位相 As shown in FIG. 11, the phase at which the thrust generated by the first stator member 41 has a peak value is different from the phase at which the thrust generated by the second stator member 42 has a peak value. For example, when L = τp, in order to generate the maximum thrust in the first stator member 41, the phase difference θ between the current i and the q axis needs to be 0 °. FIG. 12 shows a state where the phase difference between the current and the q-axis is 0 ° in the linear motor according to the fifth embodiment. In order for the first stator member 41 to generate the maximum thrust, id = 0 and iq = i need to be satisfied.

In the state of the current phase shown in FIG. 12, when the mover 3 enters the second stator member 42 from the first stator member 41, the thrust is 0 because the phase difference θ = 0 ° as shown in FIG. Does not occur. In order to generate a thrust when L = τp, it is necessary to detect that the mover 3 has entered the second stator member 42 and to perform control to change the current phase, making it difficult to perform smooth driving. It is.

FIG. 13 is a diagram showing the relationship between the d-axis and the q-axis and the current when the mover of the linear motor according to the fifth embodiment has entered the second stator member. In the linear motor 1 according to the fifth embodiment, by setting the distance L to be τp / 2 <L <τp, when the mover 3 enters the second stator member 42, as shown in FIG. The phases of the axis and the q axis advance. That is, the phase difference θ between the current i and the q axis is −90 ° <θ <0 °, and thrust can be generated on the second stator member 42 without performing current control on the inverter 70 side. It becomes possible. Thus, a smooth drive can be performed at the connection between the first stator member 41 and the second stator member 42.

From the above, it is desirable that the distance L is τp / 2 <L <τp. Further, as shown in FIG. 11, the thrust generated by the second stator member 42 has a periodicity, and is 180 ° in one cycle. Since the pole pitch τp is 180 ° in electrical angle, the distance L may be τp / 2 + (n−1) τp <L <nτp.

Further, as shown in FIG. 11, the thrust generated by the second stator member 42 can secure 50% of the maximum thrust if the phase difference θ is −75 ° ≦ θ ≦ −15 °. Therefore, it is more preferable that the distance L is 2τp / 3 + (n−1) τp <L <7τp / 8 + (n−1) τp.

The center distance 1 of the magnetic flux guide 421 is 3τp / 4 + (m−1) τp ≦ l ≦ mτp, and when m is an integer of 1 or more, the second distance from the first stator member 41 to the second It is possible to suppress the damping force from acting on the mover 3 that has entered the stator member 42.

The functions of the control device 80 according to Embodiments 1 to 5 are realized by a processing circuit. The processing circuit may be dedicated hardware or an arithmetic device that executes a program stored in a storage device.

If the processing circuit is dedicated hardware, the processing circuit may be a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an application specific integrated circuit, a field programmable gate array, or a combination thereof. Is applicable. FIG. 14 is a diagram illustrating a configuration in which the functions of the control devices according to the first to fifth embodiments are implemented by hardware. The processing circuit 29 incorporates a logic circuit 29a for realizing the function of the control device 80. The hardware that implements the processing circuit 29 can be exemplified by a microcontroller.

When the processing circuit 29 is an arithmetic device, the function of the control device 80 is realized by software, firmware, or a combination of software and firmware.

FIG. 15 is a diagram illustrating a configuration in which the functions of the control device according to the first to fifth embodiments are implemented by software. The processing circuit 29 includes an arithmetic unit 291 that executes the program 29b, a random access memory 292 used by the arithmetic unit 291 for a work area, and a storage device 293 that stores the program 29b. The function of the control device 80 is realized by the arithmetic device 291 developing and executing the program 29b stored in the storage device 293 on the random access memory 292. The software or firmware is described in a programming language and stored in the storage device 293. The arithmetic unit 291 can be, but is not limited to, a central processing unit.

The processing circuit 29 implements the function of the control device 80 by reading and executing the program 29b stored in the storage device 293. It can be said that the program 29b causes a computer to execute a procedure and a method for realizing the function of the control device 80.

Note that the processing circuit 29 may be partially realized by dedicated hardware and partially realized by software or firmware.

As described above, the processing circuit 29 can realize the above-described functions by hardware, software, firmware, or a combination thereof.

The configurations described in the above embodiments are merely examples of the contents of the present invention, and can be combined with other known technologies, and can be combined with other known technologies without departing from the gist of the present invention. Parts can be omitted or changed.

1 linear motor, 2 slider, 3 mover, 4 stator, 5 guide, 29 processing circuit, 29a logic circuit, 29b program, 31 mover core, 33 winding, 41 first stator member, 42 second Stator member, 50 linear motor system, 60 power supply, 70 inverter, 80 control device, 291 arithmetic unit, 292 random access memory, 293 storage device, 311 core back, 312 teeth, 411 permanent magnet, 412 first stator core , 413, 426} magnetic pole face, 421, magnetic flux guide, 422, second stator core, 423, consequent part, 424, magnet mounting part, 425, slit hole.

Claims (16)

A stator of a linear motor serving as a transfer path of the mover,
A first stator member having a permanent magnet disposed along the moving direction of the mover,
A second stator member, which is made of a soft magnetic material and has a magnetic flux guide portion disposed along the traveling direction of the mover,
A stator for a linear motor, wherein the first stator member and the second stator member are arranged in series along a traveling direction of the mover. In the first stator member, the permanent magnets are arranged at a pole pitch τp,
At a connecting portion between the first stator member and the second stator member, the first fixed member is moved from the center in the traveling direction of a magnetic pole surface disposed at an end in the traveling direction of the first stator member. The distance L between the magnetic pole surface of the second stator member and the center of the magnetic pole surface of the second stator member adjacent to the magnetic pole surface in the traveling direction is τp / 2 + (n−1) τp ≦ L ≦ nτp, and n is 1 or more. 2. The linear motor stator according to claim 1, wherein the stator is an integer. The stator according to claim 2, wherein the distance L satisfies 2τp / 3 + (n−1) τp ≦ L ≦ 7τp / 8 + (n−1) τp. The center distance 1 of the magnetic flux guides adjacent in the moving direction of the mover is 3τp / 4 + (m−1) τp ≦ l ≦ mτp, and m is an integer of 1 or more. 4. The stator of the linear motor according to any one of 1 to 3. The stator according to any one of claims 1 to 4, wherein the second stator member includes a permanent magnet arranged along a traveling direction of the mover. The said permanent magnet arrange | positioned at a front 2nd stator member differs in the shape or the residual magnetic flux density from the said permanent magnet arrange | positioned at the said 1st stator member, The Claim 5 characterized by the above-mentioned. Linear motor stator. The dimension of the permanent magnet disposed on the second stator member in a direction perpendicular to a traveling direction of the mover and perpendicular to a direction from the stator toward the mover is the first stator. 7. The linear motor stator according to claim 6, wherein the stator is longer as being closer to the member. The dimension of the permanent magnet disposed on the second stator member in a direction perpendicular to the moving direction of the mover and in the direction from the stator to the mover side is closer to the first stator member. The stator for a linear motor according to claim 6, wherein the stator is long. 9. The linear motor according to claim 6, wherein a residual magnetic flux density of the permanent magnet disposed on the second stator member is larger as the permanent magnet density is closer to the first stator member. 10. Motor stator. The stator according to any one of claims 1 to 9, wherein the magnetic flux guide portion of the second stator member is formed by a protrusion protruding from a magnetic yoke. 10. The linear motor according to claim 1, wherein the magnetic flux guide of the second stator member is formed by a plurality of slit holes provided in a magnetic yoke. Stator. 2. The apparatus according to claim 1, wherein the first stator member is disposed in a section in which the mover is accelerated and decelerated, and the second stator member is disposed in a section in which the mover is moved at a constant speed. 3. 12. The stator for a linear motor according to any one of items 11 to 11. A linear motor, comprising: the stator of the linear motor according to any one of claims 1 to 12; and a mover. A distance G1 between the magnetic pole surface of the first stator member and the mover when the first stator member and the mover face each other, the second stator member and the mover 14. The linear motor according to claim 13, wherein a distance G2 between the magnetic pole surface of the second stator member and the mover when the magnetic poles face each other is G1 ≧ G2. The linear motor according to claim 14, wherein a distance G2 between the magnetic pole surface of the second stator member and the mover is longer as the distance is closer to the first stator member. A linear motor according to any one of claims 13 to 15,
A control device for controlling the moving direction and moving speed of the mover,
The controller is configured to drive the movable element without a sensor when the movable element passes over the second stator member.

Images