Device for braking single-side permanent magnet linear motor

Abstract

The invention discloses a device for braking a unilateral permanent magnet linear motor, and the device comprises a workbench which is used for fixing an electric mechanical clamp, a rotor primary iron core and a primary winding; the primary winding is wound on the rotor primary iron core; the guide rail is used for guiding the sliding direction of the workbench; the electric mechanical clamp is fixed to the workbench and used for driving the two friction plates to move inwards or outwards, and friction braking or separation of the fixing sleeve is achieved. The fixing sleeve is used for fixing the stator secondary iron core and serves as a friction contact part of the friction plate; a permanent magnet is fixed on the secondary iron core; the control circuit is used for selecting energization of the power supply and the primary winding or the electric mechanical clamp, a traveling wave magnetic field is generated when the primary winding is energized, and the magnetic field and a magnetic field generated by the permanent magnet jointly act to push the workbench to do linear motion; when the electric mechanical clamp is powered on, the friction plate is driven to move inwards to make contact with the fixing sleeve to generate friction force so that the workbench can stop moving, and timely braking and clamping are achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of permanent magnet linear motor braking, and in particular relates to a device for braking a single-sided permanent magnet linear motor under normal power-off conditions. Background Art

[0002] The single-sided permanent magnet linear motor is the most basic structural form in the linear motor series. It is mainly composed of a primary iron core and an AC coil, a secondary permanent magnet and an air gap between the primary and secondary. The AC coil is wound on the primary iron core. When the coil is connected to the current, it will be subjected to a magnetic field force under the action of the magnetic field exerted by the permanent magnet. Its direction is related to the direction of the current and can be derived from the left-hand rule. When the magnetic field force on the coil is greater than its friction resistance, the coil can move linearly along the iron core axis. The introduction of AC current can also realize the reciprocating linear motion of the linear motor. This type of motor has a stable structure, high rigidity, unlimited travel, and relatively low manufacturing cost. It is very suitable for the feed drive requirements of the CNC machine tool worktable.

[0003] The Chinese invention patent with the patent application number "201710839847.2" and the name of "Linear Motor Braking Device" has developed a device for single-sided and double-sided linear motor braking. However, the above device only uses the change in the magnitude of the electromagnetic force in the two states of power on and off to achieve braking, and there are accidental factors. In many cases, due to the non-parallelism of the working plane or the unevenness of the magnetic material, the change in the magnitude of the electromagnetic force is often not very obvious. Therefore, it is difficult to ensure that the above work can achieve timely braking, especially the strength of the electromagnetic force will be affected by a variety of external factors, which makes the actual result have unpredictable deviations, and buries hidden dangers for the emergency braking of the linear motor. Summary of the invention

[0004] The object of the present invention is to provide a method for simultaneously controlling a linear motor and a braking device by an external circuit, so as to achieve the fastest response to the braking of the linear motor and improve the continuity and accuracy of the braking of the linear motor.

[0005] The technical solution to achieve the purpose of the present invention is:

[0006] A device for braking a single-sided permanent magnet linear motor, comprising:

[0007] A workbench, used for fixing the electric mechanical fixture, the primary iron core of the mover and the primary winding; the primary winding is wound on the primary iron core of the mover;

[0008] A guide rail, used to guide the sliding direction of the workbench;

[0009] An electric mechanical fixture is fixed on the workbench and is used to drive the two friction plates to move inward or outward to achieve friction braking or separation of the fixed sleeve;

[0010] A fixed sleeve is used to fix the secondary iron core of the stator and serves as a friction contact part of the friction plate; a permanent magnet is fixed on the secondary iron core;

[0011] The control circuit is used to select the power supply and the primary winding or the electric mechanical fixture to be energized. When the primary winding is energized, a traveling wave magnetic field is generated. The magnetic field and the magnetic field generated by the permanent magnet work together to push the workbench to move in a straight line. When the electric mechanical fixture is energized, the friction plate is driven to move inward and contact with the fixed sleeve to generate friction to stop the workbench from moving.

[0012] Compared with the prior art, the present invention has the following significant advantages:

[0013] The friction force generated by the contact between two rubber friction plates fixed on the clamp driven by the motor and the rubber sleeve wrapped outside the stator secondary core bottom plate is used to achieve timely braking of the linear motor. The present invention shortens the braking distance of the linear motor and can be used to prevent the linear motor move continuously due to inertia, thereby achieving timely braking and clamping, thereby preventing the subsequent linear motor from changing its position due to external force when not constrained by the magnetic field. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the installation position of the device of the present invention in the linear motor.

[0015] Figure 2 It is a schematic diagram of the overall structure of the device of the present invention.

[0016] Figure 3 It is a schematic diagram of the internal structure of the device of the present invention.

[0017] Figure 4 It is a simplified schematic diagram of the external circuit of the present invention.

[0018] Figure 5 This is a working principle diagram of the linear motor of the present invention.

[0019] The meaning of symbols in the figure: 1—Electric mechanical fixture, 2—Workbench, 3—Permanent magnet, 4—Stator secondary core, 5—Rubber friction plate, 6—Rubber fixing sleeve, 7—Guide rail, 11—Motor cover, 12—Upper connecting plate, 13—Lower connecting plate, 14—Z-shaped plate, 15—T-shaped slide rail, 16—Sliding clamp, 17—Wheel disc, 18—Spring, 19—Connecting rod, 01—Motor primary core, 02—Primary winding. DETAILED DESCRIPTION

[0020] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0021] The present invention discloses a device for braking a single-sided permanent magnet linear motor, comprising an electric mechanical fixture 1, a workbench 2, a permanent magnet 3, a stator secondary core 4, a rubber friction plate 5, a rubber fixing sleeve 6, a guide rail 7, a mover primary core 01, and a primary winding 02;

[0022] like Figure 1 As shown, the electric mechanical fixture 1 is installed on the workbench 2 and moves on the guide rail 7. The permanent magnet 3 is placed on the secondary iron core 4. The outer periphery of the stator secondary iron core bottom plate is tightly wrapped with a rubber fixing sleeve 6. The rubber friction plate 5 used in conjunction with the rubber fixing sleeve 6 is connected to the fixture 1; the electric mechanical fixture 1 includes a motor cover 11, an upper connecting plate 12, a lower connecting plate 13, a Z-shaped plate 14, a T-shaped slide rail 15, a sliding clamp 16, a rotating wheel 17, a spring 18, and a connecting rod 19.

[0023] Combination Figure 2 The motor cover 11 is fixed on the upper connecting plate 12 and has an electric motor inside. The upper connecting plate 12 is clamped together with the lower connecting plate 13 through a Z-shaped plate 14 (can move up and down relative to the lower connecting plate). Two springs 18 are provided between the upper connecting plate 12 and the lower connecting plate 13 to elastically support the upper connecting plate 12. Threaded holes are drilled under the Z-shaped plate 14 and on the surface of the lower connecting plate 13 to fix it to the workbench 2. The T-shaped slide rail 15 is connected to the upper connecting plate 12 with screws, and two sliding clamps 16 move on the T-shaped slide rail 15. The entire fixture structure is symmetrical and connected as a whole. Its internal mechanical structure is as follows: Figure 3 As shown, the centers of the two rotating wheels 17 are respectively matched with the outwardly extending shafts of an electric motor, the springs 18 are symmetrically arranged on both sides, one end of the connecting rod 19 is hinged to the eccentric position of the outer ring of the wheel 17, and the other end is hinged to the slider on the sliding clamp 16.

[0024] Figure 4 The external circuit diagram of the linear motor and the mechanical fixture 1 is shown in FIG. The external circuit is provided with three-phase AC power by a three-phase AC power supply. The primary winding 02 of the linear motor and the electric motor on the mechanical fixture 1 are connected in series to the external circuit, and a double-throw switch S is set between the two. W , can be connected to point A or point B. When connected to point A, it enters the short circuit of the motor; when connected to point B, it enters the short circuit of the primary winding 02.

[0025] Figure 5The general working principle of a single-sided permanent magnet linear motor is shown. That is, after the three-phase alternating current is passed through the primary winding 02, a traveling wave magnetic field will be generated. The magnetic field and the magnetic field generated by the permanent magnet 3 will work together to generate a common thrust F on the primary core 01 of the mover and the primary winding 02, pushing the workbench 2 to move linearly. Among them, the permanent magnet 3 is fixed on the secondary core 4 of the stator, the primary winding 02 is wound on the primary core 01 of the mover, and the primary core 01 of the mover is connected to the workbench 2, leaving a certain air gap between the primary core 01 of the mover and the secondary core 4 of the stator.

[0026] The whole working process is as follows: when the primary winding 02 of the mover is energized, the workbench 2 moves linearly, the double-throw switch is now set to point A, and the motor is in a short-circuit state; when the workbench 2 completes the work and needs to stop, the double-throw switch is manually disconnected from point A and set to point B, the primary winding 02 of the mover is short-circuited, and the motor starts to work. However, the workbench 2 will not stop immediately due to inertia, so braking is required at this time. After the motor on the electric mechanical fixture 1 is connected to the circuit, the rotary motor starts to rotate, and the rotary motion is transmitted to the wheel 17 connected thereto through the rotating shaft. The outermost eccentric position on the wheel 17 is hinged with the connecting rod, and the sliding clamp 16 is now on both sides of the T-shaped slide rail 15, which is also the limit position of the crank connecting rod mechanism. Next, as the wheel 17 rotates, the sliding clamp 16 will move inward, and the rubber fixing sleeve 6 has a certain width, so it does not require a large stroke, and the turning angle can be controlled within 90 degrees. There is enough space for movement between the upper connecting plate 12 and the lower connecting plate 13, and it will not touch other components. Driven by the built-in simple crank-connecting rod mechanism, the sliding clamp 16 will quickly move toward the middle direction. When the surface of the rubber friction plate 5 connected to the sliding clamp 16 touches the surface of the rubber fixing sleeve 6, a relatively large friction force will be generated, thereby forcing the workbench 2 to stop in time, effectively shortening the braking distance of the linear motor.

[0027] In this process, there is a certain fixed relationship between the surfaces of each adjacent component, which can ensure that the braking is carried out smoothly and steadily. The motor cover 11 is fixed to the upper connecting plate 12 by four screws. The upper connecting plate 12 and the lower connecting plate 13 are clamped together by the Z-shaped plate 14 in three directions, and four threaded holes are drilled at the bottom of the Z-shaped plate 14 and the lower connecting plate 13 for installation on the workbench 2. The T-shaped slide rail 15 and the upper connecting plate 12 are also fixed by screws on the left and right sides. The rubber friction plate 5 and the sliding clamp 16 are also connected by screws. It is necessary to ensure that the two rubber friction plates 5 are installed symmetrically and parallelly, so that the friction force on the left and right sides of the workbench 2 will be uniform, and the effect of stopping at the left and right ends at the same time can be achieved. A spring 18 with both ends fixed thereon is also provided between the upper connecting plate 12 and the lower connecting plate 13. Since the electric mechanical clamp 1 is placed vertically, the purpose of setting this spring 18 is to balance the gravity on the electric mechanical clamp 1 so that a force balance state is achieved. In addition, it can also play a certain role in shock absorption and buffering during the movement process. When the linear motor needs to release the sliding clamp 16 to resume work after braking, the motor only needs to be reversed or the current direction changed. If the current direction is changed, the workbench 2 will move linearly in the opposite direction after being released. The linear motor braking device is also suitable for motors that perform reciprocating linear motion, and is also relatively easy to install. It only needs to drill a few threaded holes of appropriate size on the workbench 2.

[0028] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A device for braking a single-sided permanent magnet linear motor, characterized in that: include: A workbench, used for fixing the electric mechanical fixture, the primary iron core of the mover and the primary winding; the primary winding is wound on the primary iron core of the mover; A guide rail, used to guide the sliding direction of the workbench; An electric mechanical fixture is fixed on the workbench and is used to drive the two friction plates to move inward or outward to achieve friction braking or separation of the fixed sleeve; A fixed sleeve is used to fix the secondary iron core of the stator and serves as a friction contact part of the friction plate; a permanent magnet is fixed on the secondary iron core; The control circuit is used to select the power supply and the primary winding or the electric mechanical fixture to be energized. When the primary winding is energized, a traveling wave magnetic field is generated. The magnetic field and the magnetic field generated by the permanent magnet work together to push the workbench to move in a straight line. When the electric mechanical fixture is energized, the friction plate is driven to move inward and contact with the fixed sleeve to generate friction to stop the workbench from moving.

2. The device for braking a single-sided permanent magnet linear motor according to claim 1, characterized in that: The electric mechanical fixture includes an electric motor, an upper connecting plate, a lower connecting plate, a slide rail, a rotating wheel, a spring, and a connecting rod; An electric motor is provided on the upper connecting plate; the upper connecting plate and the lower connecting plate are clamped and can move up and down relative to the lower connecting plate; two springs are provided between the upper connecting plate and the lower connecting plate to elastically support the upper connecting plate; the lower connecting plate is fixed on the workbench; the slide rail is connected to the upper connecting plate; the centers of the two rotating wheel discs are respectively matched with an outwardly extending rotating shaft of a motor, one end of the connecting rod is hinged to the eccentric position of the outer ring of the wheel disc, and the other end is hinged to the slider on the sliding clamp, and the sliding clamp is used to fix the friction plate.

3. The device for braking a single-sided permanent magnet linear motor according to claim 2, characterized in that: The upper connecting plate is clamped together with the lower connecting plate through three Z-shaped plates.

4. The device for braking a single-sided permanent magnet linear motor according to claim 2, characterized in that: The slide rail adopts T-shaped slide rail.

5. The device for braking a single-sided permanent magnet linear motor according to claim 1, characterized in that: The control circuit adopts a double-throw switch, and the primary winding is connected in series with the electric motor on the mechanical fixture. When the double-throw switch is connected to point A, the short circuit circuit of the motor is entered; when it is connected to point B, the short circuit circuit of the primary winding is entered.

6. The device for braking a single-sided permanent magnet linear motor according to claim 1, characterized in that: The friction plate and the fixing sleeve are both made of rubber.

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