JP2009131100A - Movable table device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a movable table device which uses a linear motor capable of adjusting the power energization-off timing so as to enable improvement in power efficiency and prevention of heat generation, and which is capable of being driven by an appropriate torque. <P>SOLUTION: A moving magnet type linear motor 2 is constituted by a plurality of coils 5 arrayed on a fixed base 4, on which the movable table 1 is installed movably, along the table moving direction, and magnets 6 installed on the movable table 1 and opposing the coils 5. A position detecting means is installed which detects the relative positions of the magnets 6, with respect to the coils 5. In a control driver 21 which supplies driving power to the coils 5, a means 25 for stopping non-opposite coils is provided which stops power supply to the coils 5, to which the magnets 6 become non-opposite, based on the signals detected by the position detecting means. The position detecting means is constituted by a plurality of magnet detecting sensors 8 aligned in the coil arrangement direction. Adjustable sensor mounting means 11 are installed which mount the sensors 8 on the fixed base 4 in the coil arrangement direction so as to be variable in position. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a movable table device that is applied to industrial machines, mobile transportation means, and the like and performs linear motion or arc motion using a linear motor as a drive source.

As a conventional example of a movable table device using a linear motor, as shown in a sectional view and a side view in FIGS. 8A and 8B, a plurality of magnets 46 arranged on a fixed base 44 and a movable portion (movable table). ) A moving coil type composed of one coil 45 installed at 41 is generally used.
In the case of this type of movable table device, if the movable stroke of the movable portion 41 becomes long, the expensive magnets 46 must be arranged over the entire stroke, which makes the device expensive. In addition, since the coil 45 to which current is supplied is installed on the movable portion 41 side, the wiring 54 connected to the coil 45 is cut off by the reciprocating motion of the movable portion 41, obstructing the reciprocating operation, There is a risk of affecting straightness.

In order to solve such a problem, as a linear motor of the movable table device, as shown in a sectional view and a side view in FIGS. 9A and 9B, one coil 45 is installed on the fixed base 44, A moving magnet type in which a plurality of magnets 46 are arranged on the movable portion 41 may be employed.
In the case of the movable table device of this method, the problem in the method of FIG. 8 is solved, but if the movable stroke of the movable portion 41 becomes longer, the total length of the coil 45 also becomes longer. The current is also passed through the portion where 41 is not located. As a result, power efficiency is deteriorated and heat is generated.

Therefore, in general, when a moving magnet type linear motor is used in an industrial machine or a railway vehicle, it is necessary to divide the coil 45 as shown in the sectional view and the side view in FIGS. In many cases, power is supplied only to the coil 45 (for example, Patent Document 1).
Japanese Patent No. 3815750

  However, in the configuration of FIG. 10, the on / off timing of energization of the coil 45 may be a problem. That is, for example, when the optimal energization on / off timing is necessary depending on the speed of the movable portion 41, or when acceleration / deceleration is prioritized, it is necessary to lengthen the energization time to the coil 45. Conversely, when priority is given to power efficiency, it is necessary to shorten the energization time to the coil 45.

  A normal control system applicable to the driving of the linear motor having the configuration shown in FIG. 10 is a control system called current driving shown in FIG. In the case of this control system, the linear motor is driven by causing a current proportional to the required torque calculated by the calculation unit 62 to flow through the coil 45. In this case, it is difficult to be affected by fluctuations in the impedance of the coil 45 on the load side, and since current and torque are generally proportional, torque proportional to the command can be obtained, which is said to be an ideal control method.

  However, since the current detection circuit 63 and the feedback loop 64 are required in the control system of FIG. 11, the control system may be delayed and controllability may deteriorate.

  As another control system applicable to the driving of the linear motor having the configuration shown in FIG. 10, there is a control system called voltage driving shown in FIG. In the case of this control system, a voltage proportional to the required torque calculated by the calculation unit 62 is applied to the coil 45 as a load to drive the linear motor. In this case, assuming that there is no change in the impedance of the coil 45, a current proportional to the necessary torque is finally generated, and the necessary torque is obtained. Further, the current detection circuit 63 and the feedback loop 64 as in the control system of FIG. 11 are not required, and there is a possibility that controllability is improved without delay in the control system.

  However, in the above control system, the impedance of the coil 45 actually changes, and a torque proportional to the command is not necessarily obtained. In particular, in the case of a moving magnet type linear motor, as shown in FIGS. 13 and 14, when the magnet 46 and the coil 45 are separated from each other, the impedance of the coil 45 becomes extremely small and a large current may flow. is there. In the worst case, the coil 45 may generate heat, ignite, an overcurrent of the control system, or a failure. 13 and 14, M represents the width of the coil 45, and L represents the position of the movable portion 41 as viewed from the coil 45 (distance from the coil 45 to the movable portion 41). In FIG. 14, when the distance L is a positive value, the coil 45 and the magnet 46 are separated. When −M <L <0, the coil 45 and the magnet 46 partially overlap each other. In the case of L <−M, the coil 45 and the magnet 46 are completely overlapped.

  An object of the present invention is to provide a movable table device that uses a linear motor that can be driven with an appropriate torque and that can adjust the power-off timing of the coil so as to improve power efficiency and prevent heat generation.

According to a first aspect of the present invention, there is provided a movable table device, wherein a movable table is movably installed on a fixed base, a plurality of coils arranged on the fixed base along the movable direction of the movable table, and the coil A moving magnet type linear motor composed of a magnet installed on the movable table is provided opposite to the control table, position detecting means for detecting a relative position of the magnet with respect to the coil is provided, and control power is supplied to the coil. In the movable table device, the driver has a non-opposing coil stopping unit that stops power supply to the coil at a position where the magnet is non-opposing based on a detection signal of the position detecting unit.
The position detection means is a plurality of sensors arranged in the coil arrangement direction to detect the magnets respectively, and adjustable sensor attachment means for attaching each of these sensors to the fixed base in a coil arrangement direction is provided. It is characterized by.
In this movable table device, a moving magnet type linear motor is used as a drive source, and if power is supplied to the coil in a state where the coil and the magnet are separated, the impedance of the coil becomes extremely small. If there is no opposed coil stopping means, a large current may flow. The non-opposing coil stop means stops the power supply to the coil at the position where the magnet is non-opposing based on the detection signal of the sensor which is a position detecting means for detecting the relative position of the magnet to the coil. It is possible to prevent generation of heat and save power by preventing a large current from flowing.
Further, in this movable table device, the position detecting means is constituted by a plurality of sensors arranged in the coil arrangement direction to detect the respective magnets, and these sensors are attached to the fixed base so that the position can be changed in the coil arrangement direction. Adjustable sensor mounting means are provided. For this reason, the power supply to the coil can be stopped at an optimal timing by adjusting the position of the sensor according to the purpose of use. As a result, the power-off timing of the coil can be adjusted so that power efficiency can be improved and heat generation can be prevented, and driving can be performed with an appropriate torque.

A movable table device according to a second aspect of the present invention is the movable table device according to the first aspect, wherein, instead of the configuration in which the position detection unit is a plurality of sensors, the position detection unit is configured to continuously change the relative position of the magnet. The non-opposing coil stop means is configured to stop the power supply to the coil when the detected value of the length measuring device is compared with the set value for comparison and is in a setting relationship. A setting value storage means for storing a plurality of setting values for comparison is provided, and the setting value storage means enables the setting value to be rewritten.
Also in this configuration, the non-opposing coil stopping means supplies power to the coil at a position where the magnet is not facing based on the detection signal of the length measuring device which is a position detecting means for detecting the relative position of the magnet to the coil. Since the operation is stopped, it is possible to prevent the generation of heat and save power by preventing a large current from flowing.
Further, since the setting value storage means for storing a plurality of setting values for comparison used for the power supply stopping operation in the non-opposing coil stopping means is provided, the first invention is achieved by changing the setting value for comparison. The timing for stopping the power supply can be changed in the same manner as adjusting the position of the sensor. As a result, the power-off timing of the coil can be adjusted so that power efficiency can be improved and heat generation can be prevented, and driving can be performed with an appropriate torque.

  In the first or second aspect of the invention, the control driver calculates a necessary torque command value, converts the torque command value into a voltage value and outputs the voltage value, and a command value generator A voltage-driven control driver having an open-loop drive current supply path that converts an output voltage value into a drive current by an amplifier and supplies the converted current to the coil may be used. In the case of this configuration, a current detection circuit and a feedback loop are unnecessary, and controllability can be improved without causing a delay in the control system.

When the voltage driving method is used, the non-opposing coil stopping means of the control driver supplies current of the coil from which the magnet leaves at the timing immediately before the magnet leaves from the coil based on the detection signal of the position detecting means. It may be something that stops.
As described above, the sensor position adjustment in the first invention and the setting storage means in the second invention are stored so that the current supply of the coil from which the magnet is separated is stopped immediately before the magnet is separated from the coil. If the set value for comparison is changed, a large current caused by a sudden drop in the coil impedance can be prevented.

In the first or second aspect of the invention, the plurality of coils are disposed at intervals in the arrangement direction, and the control driver supplies a current that is inversely proportional to the number of coils that are in a driving state at the same time. May be.
In this way, when the control driver is configured, the linear motor can always be driven with a constant torque without being influenced by the position of the movable table, so that it is possible to reduce unevenness in moving speed and gain in the movable table.

  In the second aspect of the invention, the non-opposing coil stopping means of the control driver continuously observes the detection signal of the position detecting means, and stops power supply to the coil at a position where the magnet is non-opposing. May be performed so that the power gradually decreases. In the case of this configuration, the variation in the moving speed of the movable table is reduced, and the movable table can be operated smoothly.

According to a first aspect of the present invention, there is provided a movable table device, wherein a movable table is movably installed on a fixed base, a plurality of coils arranged on the fixed base along the movable direction of the movable table, and the coil A moving magnet type linear motor composed of a magnet installed on the movable table is provided opposite to the control table, position detecting means for detecting a relative position of the magnet with respect to the coil is provided, and control power is supplied to the coil. In the movable table device in which the driver has non-opposing coil stopping means for stopping power supply to the coil at the position where the magnet is non-opposing based on the detection signal of the position detecting means, the position detecting means is arranged in a coil arrangement. A plurality of sensors are arranged in the direction to detect the magnets, and the sensors are arranged in the coil arrangement direction with respect to the fixed base. Due to the provision of an adjustable sensor mounting means for mounting the possible location change, to adjust the de-energization timing to the coil so as to allow improvement and preventing heat generation in power efficiency, can be driven at an appropriate torque.
In the movable table device according to a second aspect of the present invention, the position detecting means is a length measuring device capable of continuously detecting the relative position of the magnet, and the non-opposing coil stopping means is the length measuring device. When the detected value is compared with the set value for comparison, the power supply to the coil is stopped when there is a set relationship, and a set value storage means for storing a plurality of set values for comparison is provided. Since the storage means can rewrite the set value, the power-off timing of the coil can be adjusted so that power efficiency can be improved and heat generation can be prevented, and the storage means can be driven with an appropriate torque.

  An embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1A, the movable table device of this embodiment includes a mechanism unit 20 having a movable table 1 and a moving magnet type linear motor 2, a control driver 21 such as an electric circuit for driving the linear motor 2, and the like. It becomes. As shown in FIG. 1B showing a side view of the mechanism section 20, the movable table 1 is guided by the guide 3 and moves along a predetermined path such as a linear path or an arc-shaped path on the fixed base 4. It is installed freely. 1A shows a cross-sectional view taken along the arrow Ia-Ia in FIG.

  The linear motor 2 includes a plurality of three-phase coils 5 arranged on a fixed base 4 along the movable direction of the movable table 1 and a plurality of magnets installed on the lower surface of the movable table 1 so as to face the coils 5. 6 The plurality of coils 5 may be arranged in close contact with each other or arranged at an appropriate interval. The coil 5 may be a core (iron core) or a coreless one. The plurality of magnets 6 are arranged in a plane so that the magnetic poles N and S are alternately arranged in the movable direction of the movable table 1 and are located close to the coil 5. Here, the magnets 6 are arranged in two rows so that the coils 5 are sandwiched between them, and the magnetic poles N and S that sandwich the coils 5 in each row are in different combinations as shown in FIG. A part of the two rows of magnets 6 may be connected by a magnetic body 7 called a yoke. In this case, the function of the magnets 6 becomes stronger and the efficiency can be increased.

  The mechanism unit 20 is provided with a plurality of sensors 8 which are position detection means for detecting the relative position of the magnet 6 with respect to the coil 5. These sensors 8 are arranged on the fixed base 4 in parallel with the arrangement of the coils 5, and are provided on the lower surface of the movable table 1 to detect the dogs 10 serving as the sensor targets of the sensors 8. Each magnet 6 is detected. As the sensor 8, a photoelectric sensor, a mechanical switch, a sensor for sensing an object with eddy current, or the like can be used. The number of sensors 8 is the same as the number of coils 5 that are divided and arranged as a standard.

  Each of the sensors 8 is provided on the fixed base 4 via an adjustable sensor mounting means 11 as shown in an enlarged view in FIG. The adjustable sensor mounting means 11 is a means for mounting the sensor 8 so that the position of the fixed base 4 can be changed in the arrangement direction of the coil 5. The sensor mounting base 12 fixed on the fixed base 4, and the sensor mounting The sensor mounting screw 13 is used to fasten the sensor 8 to the base 12. The sensor mounting base 12 is provided with a long hole (not shown) that extends in the arrangement direction of the coils 5 and that the sensor 8 is movably engaged in that direction. The sensor mounting base 12 is fastened with the mounting screw 13. Thereby, the position of the sensor 8 can be changed by loosening the sensor mounting screw 13.

  The control driver 21 is means for controlling the movement of the movable table 1 by supplying driving power to the coil 5 via the wiring 14, and its schematic configuration is shown in a block diagram in FIG. The control driver 21 calculates a necessary torque command value, converts the torque command value into a voltage value and outputs the voltage value, and outputs a voltage value output from the command value generation unit 22 to an amplifier 24. The voltage drive system has an open-loop drive current supply path 23 that is converted into drive current and supplied to the coil 5. The command value generation unit 22 calculates the necessary torque command value from, for example, the difference between the current position and the target position, the difference between the current speed and the target speed, and the like. The control driver 21 has non-opposing coil stopping means 25 for stopping power supply to the coil 5 at a position where the magnet 6 is non-opposing based on the detection signal of the sensor 8 serving as position detecting means.

In this movable table device, the moving magnet type linear motor 2 is used as a drive source, and when the power is supplied to the coil 5 in a state where the coil 5 and the magnet 6 are separated from each other, the impedance of the coil 5 becomes extremely small. If there is no non-opposing coil stop means 25, a large current may flow. The non-opposing coil stop means 25 stops the power supply to the coil 5 at a position where the magnet 6 is non-opposing based on the detection signal of the sensor 8 which is a position detecting means for detecting the relative position of the magnet 6 to the coil 5. Therefore, it is possible to prevent the generation of heat and save power by preventing a large current from flowing.
Further, in this movable table device, a position detecting means is constituted by a plurality of sensors 8 arranged in the coil arrangement direction to detect the respective magnets 6, and these sensors 8 are positioned in the coil arrangement direction with respect to the fixed base 4. Adjustable sensor mounting means 11 is provided for mounting in a changeable manner. For this reason, the power supply to the coil 5 can be stopped at an optimum timing by adjusting the position of the sensor 8 according to the purpose of use. For example, if the position of the sensor 8 is adjusted so that the current supply to the coil 5 from which the magnet 6 leaves is stopped at the timing immediately before the magnet 6 leaves the coil 5, the impedance of the coil 5 rapidly decreases. Can prevent a large current flowing through.

  In this embodiment, as shown in FIG. 3, the control driver 21 calculates a necessary torque command value, converts the torque command value into a voltage value, and outputs the command value generation unit 22. Since the voltage value output from the value generator 22 is converted into a drive current by the amplifier 24 and is supplied to the coil 5, the voltage drive system has an open-loop drive current supply path 23, which eliminates the need for a current detection circuit and a feedback loop. Thus, controllability can be improved without delay in the control system.

  Further, in this embodiment, the plurality of coils 5 are installed at intervals in the arrangement direction. For example, as shown in a block diagram in FIG. It is also possible to confirm the number of coils 5 that are simultaneously driven from the detection signal and supply a current that is inversely proportional to the number to the coils 5. In FIG. 4, the drive state coil number determination means 26 confirms the number of coils 5 that are in the drive state simultaneously from the detection signal of the sensor 8, and the command value generation unit 22 is inversely proportional to the confirmation number based on the confirmation result. A voltage value such that current flows through the coil 5 is output.

  In this way, when the control driver 21 is configured, the linear motor 2 can always be driven with a constant torque without being influenced by the position of the movable table 1, so that unevenness in the moving speed and gain in the movable table 1 can be reduced.

  5 and 6 show another embodiment of the present invention. In this embodiment, in the movable table device of FIGS. 1 to 3, a length measuring device 9 capable of continuously detecting the relative position of the magnet 6 is used as position detection means for detecting the relative position of the magnet 6 to the coil 5. When the non-opposing coil stopping means 25 of the control driver 25 is used, the detection value L of the length measuring device 9 is compared by the comparison set value a and the comparator 27, and the comparison result is in a predetermined setting relationship. In addition, the power supply to the coil 5 is stopped. In this case, the set value a is a value determined by a predetermined positional relationship between the coil 5 and the magnet 6. The set value a is stored by the set value storage means 28. The set value storage means 28 stores a plurality of the set values a, and the set values a can be rewritten. When the detection value L of the length measuring instrument 9, that is, the relative position of the magnet 6 to the coil 5 is larger than the set value a, the relay 29 interposed in the drive current supply path 23 is turned off by the output signal of the comparator 27, The coil current is cut off. The non-opposing coil stopping means 25 including the relay 29 is necessary for each coil 5. Although it is possible to distribute power from one unit to each coil, one amplifier 24 may be provided for each coil 5. Here, the configuration of the mechanism unit 20 in FIG. 1A is not shown, but other configurations including the mechanism unit 20 are the same as those in the embodiment of FIGS.

In the case of this embodiment, as shown in FIG. 6, when the detected value L (relative position of the magnet 6 with respect to the coil 5) L is greater than the set value a, no large current flows through the coil 5.
Moreover, if the setting value a for comparison is changed, the timing of stopping the power supply can be changed in the same manner as adjusting the position of the sensor 8 in the embodiment of FIGS.

  FIG. 7 shows still another embodiment of the present invention. In this embodiment, in the embodiment shown in FIGS. 5 and 6, the non-opposing coil stopping means 25 of the control driver 25 continuously observes the detection signal of the length measuring device 9 as the position detecting means, and the magnet 6 Is configured to stop the power supply to the coil 5 at the position where the non-facing is made so that the power gradually decreases. In this case, in place of the relay 29 in FIG. 6, current attenuating means 30 for gradually attenuating the current is interposed in the drive current supply path 23, and the current is attenuated by the output signal of the comparator 27 and the detected value L of the length measuring device 9. The damping operation of the means 30 is controlled. That is, when the detection value L of the length measuring device 9 becomes larger than the set value a and the output signal of the comparator 27 is inverted, the current attenuating means 30 is applied to the coil 5 in accordance with the change of the detection signal of the length measuring device 9. The flowing current is gradually attenuated. The current attenuating means 30 can constitute a circuit with a relay or an electronic switch. Instead of the current attenuating means 30 in FIG. 7, a configuration may be adopted in which the amplification factor of the amplifier 24 is gradually attenuated. In this case, the comparator 27 may change the amplification factor appropriately from the relationship of the difference between the detection value L and the set value a, not simply ON / OFF control. Other configurations of the control driver 21 are the same as those in the embodiment of FIG. Also, here, the configuration of the mechanism unit 20 in FIG. 1A is not shown, but the configuration of the mechanism unit 20 is the same as that of the embodiment of FIGS.

  In the case of this embodiment, the positional relationship between the coil 5 and the magnet 6 is continuously observed by the length measuring device 9 which is a position detecting means, and the power supply is stopped by gradually attenuating the coil current. The unevenness of the moving speed is reduced, and the movable table 1 can be operated smoothly.

(A) is the schematic of the movable table apparatus concerning one Embodiment of this invention, (B) is a side view of the mechanism part, (C) is an enlarged view of the adjustable sensor attachment means in the mechanism part. It is a perspective view which shows one structure of the magnet in the movable table apparatus. It is a block diagram which shows schematic structure of the driver for control in the movable table apparatus. It is a block diagram which shows the other structural example of the driver for control. It is a block diagram which shows schematic structure of the driver for control in the movable table apparatus concerning other embodiment of this invention. It is operation | movement explanatory drawing of the driver for control. It is a block diagram which shows schematic structure of the driver for control in the movable table apparatus concerning further another embodiment of this invention. (A) is sectional drawing of a prior art example, (B) is the side view. (A) is sectional drawing of another prior art example, (B) is the same side view. (A) is sectional drawing of another prior art example, (B) is the same side view. It is a block diagram which shows the example of 1 structure of the driver for control in a prior art example. It is a block diagram which shows the other structural example of the driver for control in a prior art example. It is explanatory drawing about the distance between a coil and a magnet and coil width in the prior art example of FIG. It is explanatory drawing which shows the relationship between the distance between coil magnets, a coil current, and an impedance in the prior art example of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Movable table 2 ... Moving magnet type linear motor 4 ... Fixed mount 5 ... Coil 6 ... Magnet 8 ... Sensor (position detection means)
9. Length measuring device (position detection means)
DESCRIPTION OF SYMBOLS 11 ... Adjustable sensor attachment means 21 ... Control driver 22 ... Command value generation part 23 ... Drive current supply path 24 ... Amplifier 25 ... Non-opposing coil stop means 26 ... Drive state coil number confirmation means 27 ... Comparator 28 ... Setting value storage Means 29 ... Relay 30 ... Current attenuation means

Claims (6)

A movable table is movably installed on the fixed gantry, and a plurality of coils arranged on the fixed gantry along the movable direction of the movable table, and a magnet installed on the movable table so as to face the coils. A moving magnet type linear motor is provided, a position detection means for detecting a relative position of the magnet to the coil is provided, and a control driver for supplying driving power to the coil is based on a detection signal of the position detection means. In the movable table device having non-opposing coil stop means for stopping power supply to the coil at a position where the magnet is non-opposing,
The position detection means is a plurality of sensors arranged in the coil arrangement direction to detect the magnets respectively, and adjustable sensor attachment means for attaching each of these sensors to the fixed base in a coil arrangement direction is provided. A movable table device characterized by the above. A movable table is movably installed on the fixed gantry, and a plurality of coils arranged on the fixed gantry along the movable direction of the movable table, and a magnet installed on the movable table so as to face the coils. A moving magnet type linear motor is provided, a position detection means for detecting a relative position of the magnet to the coil is provided, and a control driver for supplying driving power to the coil is based on a detection signal of the position detection means. In the movable table device having non-opposing coil stop means for stopping power supply to the coil at a position where the magnet is non-opposing,
The position detecting means is a length measuring device capable of continuously detecting the relative position of the magnet, and the non-opposing coil stopping means is set by comparing the detected value of the length measuring device with a set value for comparison. When there is a relationship, the power supply to the coil is stopped, and a setting value storage means for storing a plurality of setting values for comparison is provided, and this setting value storage means is movable so that the setting values can be rewritten. Table device.   3. The command value generating unit according to claim 1, wherein the control driver calculates a necessary torque command value, converts the torque command value into a voltage value, and outputs the voltage value, and an output of the command value generating unit A movable table device, which is a voltage-driven control driver, having an open-loop drive current supply path that converts a voltage value to be converted into a drive current by an amplifier and supplies the converted current to a coil.   4. The non-opposing coil stopping means of the control driver according to claim 3, wherein the non-opposing coil stopping means of the control driver stops the supply of the current of the coil from which the magnet is released at a timing immediately before the magnet is released from the coil based on the detection signal of the position detecting means. Table device.   3. The movable table device according to claim 1 or 2, wherein the plurality of coils are installed at intervals in the arrangement direction, and the control driver supplies a current that is inversely proportional to the number of coils that are simultaneously driven.   In Claim 2, the non-opposing coil stopping means of the control driver continuously observes the detection signal of the position detecting means, and stops the power supply to the coil at a position where the magnet is non-opposing. A movable table device that gradually reduces power.

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