JP6724839B2 - Linear drive - Google Patents

Description

The present invention is to realize a mechanical braking mechanism for braking a mover with a simple structure in a linear drive device.

As a brake mechanism of a conventional linear drive device, there is a brake mechanism that electromagnetically brakes by operating a current pattern to a coil (for example, Patent Document 1). With this configuration, the braking function could not be exerted when power was lost.

On the other hand, as a configuration capable of exhibiting a braking function when power is lost, there is a configuration in which a mechanical braking mechanism is opened/closed by electromagnetic attraction of a coil to perform mechanical braking (for example, Patent Document 2).

Japanese Patent Laid-Open No. 5-22926

JP-A-8-317624

When the mechanical braking mechanism is operated by the electromagnetic attraction force of the coil used for propulsion as in Patent Document 2, the application of the propulsive force and the opening/closing of the braking cannot be operated independently, so that the braking mechanism is closed. There is a problem that the movable element is not positioned during the period from the start to the end, and the stop position is displaced due to the influence of external disturbance such as external force or vibration.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to realize a linear drive device with a brake having high positional accuracy during braking.

In order to solve the above-described problems, a linear drive device according to the present invention includes a mover provided with a drive permanent magnet, and a plurality of elements arranged at a position facing the drive permanent magnet along a moving direction of the mover. And a stator having a coil, and the mover is connected to the braking permanent magnet and a braking side permanent magnet at a position facing the plurality of coils with a predetermined distance from the driving permanent magnet. The moving part-side braking part is provided, and the driving current pattern for controlling the position of the moving part is applied to the coil at the position facing the driving permanent magnet among the plurality of coils, and the coil for braking is applied. A braking current pattern for controlling the braking state of the mover-side braking portion is applied to the coil at a position facing the permanent magnet.

According to the present invention, since the energization is controlled so that the propulsion operation and the braking operation are performed by using different coils out of a plurality of coils arranged side by side, a linear drive device having high position accuracy during braking is provided. Can be realized.

Diagram showing the mover structure of the linear drive device Diagram showing the stator structure of the linear drive device XX sectional drawing showing the state at the time of braking of a linear drive device XX sectional drawing showing the state at the time of a drive of a linear drive device YY sectional drawing showing the state at the time of a drive of a linear drive device. Diagram showing cross-sectional shapes of brake shoes and brake pads Diagram showing the connection relationship between the drive amplifier and coil of the linear drive device Diagram showing the system configuration of the linear drive device Drive current waveform of linear drive The figure showing the drive position of the timing t1 of a linear drive device. The figure showing the drive position of the timing t2 of a linear drive device. The figure showing the drive position of the timing t3 of a linear drive device. The figure showing the drive position of the timing t4 of a linear drive device. The figure showing the modification of the sectional shape of the brake shoe and the brake pad.

Embodiments of a linear drive device according to the present invention will be described below in detail with reference to the drawings. The present invention is not limited to the embodiments.

Embodiment.
Embodiments of the present invention will be described below.

1 and 2 are schematic views showing the structures of the mover 1 and the stator 2 of the linear drive device. 3 and 4 are sectional views taken along line XX in FIGS. 1 and 2 in a state where the mover 1 and the stator 2 are combined. FIG. 3 shows a braking state, and FIG. 4 shows a driving state. FIG. 5 is a sectional view taken along line YY in FIGS. 1 and 2 in a state where the mover 1 and the stator 2 are combined.

As shown in FIG. 2, coils 11 are arranged in a row in the stator 2 along the driving direction of the mover 1. Two rails 9 are provided on both sides of the stator 2. A brake pad 10, which is a stator-side braking portion, is arranged inside the rail 9, and a scale 8 for position detection is arranged outside the rail 9 so as to extend parallel to the rail 9.

As shown in FIG. 1, in the mover 1, a pair of drive permanent magnets 3 and a braking permanent magnet 5 are arranged on the same axis along the drive direction of the mover 1 at predetermined intervals. Are arranged. Further, two guides 7 that engage with the rails 9 provided on the stator 2 and restrict the moving direction of the mover 1 are arranged on both sides of the mover 1. When the guide 7 is engaged with the rail 9, the driving permanent magnets 3 and the braking permanent magnets 5 move while always facing the coils 11 arranged in a line. A position detector 4 for detecting the position of the mover 1 is arranged outside the guide 7. The braking permanent magnet 5 is connected to the brake shoe 6 that is a mover-side braking portion, and is configured to operate along the brake guide 21.

The brake shoe 6 is made of a rubber material, and the brake pad 10 is made of a metal material. The cross-sectional shapes of the brake shoe 6 and the brake pad 10 are as shown in FIG. 6, and grooves are formed on the sliding surface side of the brake shoe 6.

In a state where no current is applied to the coil 11, the brake shoe 6 is pressed against the brake pad 10 provided on the stator 2 by the urging force of the urging means (coil spring) 22, as shown in FIG. Status). In the braking state, the mover 1 is fixed.

On the other hand, by applying a current to the coil 11, the brake shoe 6 is separated from the brake pad 10 via the braking permanent magnet 5 as shown in FIG. Can be driven (non-braking state).

Specifically, in the state of FIG. 5, current may be passed through the coils 111 and 112 of the segment facing the braking permanent magnet 5 so as to push up the braking permanent magnet 5. Further, in this state, by supplying a driving current for moving the mover 1 to the coils 113, 114, 115, and 116 of the segment facing the driving permanent magnet 3 by acting on the driving permanent magnet 3. The mover 1 can be operated appropriately. At this time, since the coil 111 and the coil 112 have a timing when they do not act on the operation of the mover 1, they do not affect the operation of the mover even when they are used to push up the braking permanent magnet 5.

As shown in FIG. 7, the coils 11 provided on the stator 2 are connected to the drive amplifier 12 with three coils as one unit. The range in which the mover 1 is driven can be adjusted by increasing or decreasing the number of units to be arranged.

The system configuration of the linear drive device is shown in FIG. The controller 13 controls the position of the mover 1 by grasping the position of the mover 1 from the signal from the position detector 4 and transmitting a control signal to the plurality of drive amplifiers 12. Although the controller 13 and the plurality of drive amplifiers 12 are serially connected in FIG. 7, they may be connected in parallel. Further, in the present embodiment, the case where the position detector 4 is provided in the mover 1 has been shown, but it is sufficient that the position detector 4 can detect the position of the mover 1 and may be provided in the stator 2.

FIG. 9 shows current waveforms to be passed through the coils 113, 114 and 115 when the mover 1 is moved in the L direction in FIG. A current waveform to be flown is shown by a broken line S2, and a current waveform to be flown through the coil 114 is shown by a two-dot chain line S3. Further, at timing t1, timing t2, timing t3, and timing t4 in FIG. 9, the mover 1 is in the positions shown in FIGS. 10-1, 10-2, 10-3, and 10-4.

At timings t1 and t2, currents (sine waves) for driving the mover 1 are applied to the coils 113, 114, and 115, respectively. Next, at the timing of t3, the current for driving the mover 1 is passed through the coils 114 and 115, but the coil 113 is pushed up to bring the braking permanent magnet 5 into the non-braking state. A constant current is flowing. At timing t4, a current for driving the mover 1 is passed through 115, but a constant current for pushing up the braking permanent magnet 5 to bring it into a non-braking state is passed through the coils 113 and 114. It has been washed away.

Although the current for releasing the brake has a constant value in the current waveform of FIG. 9, it is sufficient if the braking permanent magnet 5 can be pushed up to release the brake, and the current does not have to be the constant value. For example, the current may be a sine wave.

In this way, the current for driving and the current for releasing the brake are switched and supplied to each coil depending on the position of the mover 1. Therefore, it is necessary to separately provide a coil for switching the braking state. There is no. Further, since each coil is used for releasing the brake at the timing when it is not used for driving, the operation of the mover 1 is not adversely affected. Since the propulsion operation and the braking operation are performed by using different coils among the coils arranged in a line, independent control is possible. Therefore, the movable element 1 can be stopped at the target position by supplying a braking current and applying a brake while the driving current is being supplied and the position can be controlled.

In the current waveform of FIG. 9, the driving current waveform is an AC sine wave signal, but is not particularly limited and may be, for example, a rectangular wave signal.

Although the current for releasing the brake has a constant value in the current waveform of FIG. 9, it is sufficient if the braking permanent magnet 5 can be pushed up to release the brake, and the current does not have to be the constant value. For example, the current may be a sine wave.

In the positioning mechanism for the movable element 1 of the linear drive device of the present embodiment having the above structure and the stop position holding mechanism by the mechanical braking force, the movable element 1 is a current applied to the coil of the segment facing the drive permanent magnet 3. Positioning to a desired stop position is performed by operating the pattern. Thereafter, the braking mechanism operating current applied to the coil of the segment facing the braking permanent magnet 5 while maintaining the electromagnetic positioning state by the current application to the coil of the segment facing the driving permanent magnet 3. By weakening, the urging force of the brake shoe 6 on the brake pad 10 is restored, and a mechanical braking force is obtained.

Although the case where two driving permanent magnets 3 are arranged side by side has been shown in the present embodiment, the number and arrangement of the driving permanent magnets 3 are not particularly limited. Further, the distance between the driving permanent magnet 3 and the braking permanent magnet 5 can also be changed appropriately. If there is no restriction on the size of the mover, the mutual influence of the propulsion operation and the braking operation can be further reduced by increasing the distance between the driving permanent magnet 3 and the braking permanent magnet 5.

In the present embodiment, an example is shown in which the brake shoe 6 is made of a rubber material and the brake pad 10 is made of a metal material, but the materials of the brake shoe 6 and the brake pad 10 are not particularly limited. For example, the brake shoe 6 may be made of a metal material and the brake pad 10 may be made of a rubber material. Further, both may be rubber materials or metal materials, or other materials such as resin materials may be used. The shapes of the brake shoe 6 and the brake pad 10 are not particularly limited. The cross-sectional shape may be configured such that the brake shoe 6 and the brake pad 10 engage with each other, as shown in FIG. 11. With such a shape, the movable element 1 can be easily fixed when the power is not supplied.

In the present embodiment, the configuration has been described in which the biasing means 22 is provided to apply a biasing force that pushes the brake shoe 6 against the brake pad 10 when de-energized. For example, when the coil 11 is provided with a magnetic core, In place of the urging force of the urging means 22, the attraction force between the magnetic core and the braking permanent magnet 5 may be used. Further, gravity applied to the braking permanent magnet 5 or the brake shoe 6 may be used instead of the biasing force of the biasing means 22. In either case, the biasing means 22 can be omitted.

The linear drive device with the braking function of the above embodiment does not require a dedicated power source for braking operation, so that the device structure is simplified, but when the power is lost, the braking mechanism is automatically closed by the urging force. By doing so, the mover can be mechanically stopped. In addition, since the application of the propulsive force and the opening/closing of the braking mechanism can be operated independently in sequence during operation, deterioration of the stop position accuracy due to disturbance such as vibration or external force can be suppressed.

1 Mover, 2 Stator, 3 Driving Permanent Magnet, 4 Position Detector, 5 Braking Permanent Magnet, 6 Brake Shoe, 7 Guide, 8 Scale, 9 Rail, 10 Brake Pad, 11, 111, 112, 113, 114, 115, 116 coils, 12 driving amplifier, 13 controller, 21 brake guide, 22 biasing means.

Claims (3)

A mover having a drive permanent magnet,
A stator provided with a plurality of coils arranged at a position facing the driving permanent magnet along the moving direction of the mover;
Equipped with
The mover includes a braking permanent magnet disposed at a position facing the plurality of coils with a predetermined distance from the driving permanent magnet, and a mover-side braking portion connected to the braking side permanent magnet. ,,
Among the plurality of coils, a driving current pattern for controlling the position of the mover is applied to a coil at a position facing the driving permanent magnet, and a coil at a position facing the braking permanent magnet is applied. A linear driving device is applied with a braking current pattern for controlling the braking state of the mover-side braking portion. When the coil at the position facing the braking permanent magnet is in the non-energized state, the mover-side braking portion is biased to the stator side, and the coil at the position facing the braking permanent magnet. On the other hand, the linear drive device according to claim 1, wherein the permanent magnet for braking and the mover-side braking portion are moved in a direction away from the stator by energizing in a predetermined direction. Of the plurality of coils, a driving amplifier group is provided that switches a coil that applies a driving current pattern and a coil that applies a braking current pattern, according to the position of the mover, to supply a driving current. The linear drive device according to claim 1 or 2.

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