CN101774476B - Throwing platform based on permanent magnet linear motor - Google Patents

Abstract

The invention discloses a permanent magnet linear motor-based throwing platform, which comprises a base, two oppositely arranged iron yoke backplates, stator teeth, a permanent magnet rotor, an eddy current braking device and a control mechanism, wherein the iron yoke backplates are fixed on the base; each iron yoke backplate is provided with more than one row of stator teeth along the height direction; two stator teeth at corresponding positions on the different iron yoke backplates form a group; the stator teeth are wound with a three-phase winding connected with the control mechanism; the permanent magnet rotor is arranged in a motion channel formed between the two iron yoke backplates; the motion channel is divided into a front-end accelerating section and a tail-end braking section along the motion acceleration direction of the permanent magnet rotor; and the tail-end braking section is provided with the eddy current braking device. The permanent magnet linear motor-based throwing platform has the advantages of simple and compact structure, low cost, good reliability, large throwing force, and stable structure.

Description

Throwing platform based on permanent magnet linear motor

technical field

The invention mainly relates to the application field of a permanent magnet linear motor, in particular to a throwing platform using a permanent magnet linear motor.

Background technique

The throwing platform has a wide range of applications, such as bulk agricultural products, industrial cargo, aerospace industry, etc. In the past, the throwing platform was based on a rotating motor and a belt transmission, also based on air pressure, hydraulic pressure, and elastic bodies such as rubber bands. The aerospace industry may also use a throwing device with a higher thrust. Although belt transmission has certain controllability, its hysteresis dead zone is an uncontrollable section that cannot be overcome. Other air-hydraulic, rubber band, etc. throwing devices have poor controllability, and have high stress requirements and structural requirements for the objects to be thrown. The efficiency of the above-mentioned traditional throwing devices is not high.

The permanent magnet linear motor is used as the throwing platform, which realizes the complete controllability of the throwing stroke, and the efficiency of converting electric energy into kinetic energy of the thrown object can reach more than 80%. The permanent magnet linear motor has the advantages of simple structure, convenient control, and high thrust density, and is an ideal choice for the throwing platform. In order to make the output of the permanent magnet linear motor as large as possible, the structure as strong as possible, and the acceleration distance as long as possible, the double-sided thrust can be doubled, and the moving magnet motor can be used to avoid dragging wires.

When the permanent magnet linear motor is used to throw heavy objects in one direction, the round-trip stroke of the permanent magnet linear motor can be made asymmetrical, that is, the work stroke requires the mover and the object to be thrown to accelerate quickly, and the mover brake also needs to be delivered after the object is sent out. Very soon, and the mover itself only needs to return at a slow speed when returning to the stroke, without affecting the work done next time. This application background provides conditions for implementing the braking of the permanent magnet linear motor mover through structural design.

Contents of the invention

The technical problem to be solved by the present invention is: aiming at the technical problems existing in the prior art, the present invention provides a permanent magnet linear motor-based throwing machine with simple and compact structure, low cost, good reliability, large throwing force and stable structure. Send platform.

In order to solve the above technical problems, the present invention adopts the following technical solutions.

A throwing platform based on a permanent magnet linear motor, characterized in that it includes a base, two oppositely arranged iron yoke back plates, stator teeth, a permanent magnet mover, an eddy current braking device and a control mechanism, the iron yoke The back plate is fixed on the base, and each iron yoke back plate is equipped with more than one row of stator teeth along the height direction, and two stator teeth at corresponding positions on different iron yoke back plates form a group. A three-phase winding connected to the control mechanism is wound around the teeth. The permanent magnet mover is installed in the movement channel formed between the two iron yoke back plates, along the acceleration direction of the permanent magnet mover movement. The movement channel is divided into a front end acceleration section and a tail end braking section, and an eddy current brake device is installed on the tail end braking section.

As a further improvement of the present invention:

The corresponding positions of the two iron yoke back plates are provided with more than one guide rail, and the sides of the permanent magnet mover are slidably arranged on the guide rails.

The side of the permanent magnet mover is provided with rollers, and the rollers are slidably arranged on the guide rails.

The bottom surface of the permanent magnet mover is slid on the base through rollers.

The tail end of the guide rail is provided with more than one guide rail braking spring.

The stator teeth at the acceleration section at the front end are silicon steel laminated stator teeth, and the stator teeth at the braking section at the rear end are solid iron stator teeth, which constitute an eddy current braking device.

A baffle is arranged on the base, and the baffle is arranged at the tail end of the iron yoke backboard, and more than one braking spring is arranged on the baffle.

The control mechanism is connected with a position detecting device for detecting the moving position of the permanent magnet mover.

Compared with the prior art, the advantage of the present invention is that: the throwing platform based on the permanent magnet linear motor of the present invention has simple and compact structure, low cost and good reliability, and adopts the design of bilateral permanent magnet linear motor, thereby greatly improving The thrust is improved; the permanent magnet mover is used to avoid the failure caused by dragging the power supply cable back and forth. The invention adopts the structure of solid core stator teeth in the braking section at the tail end, which can greatly shorten the braking time and braking distance of the permanent magnet mover, thereby relatively lengthening the throwing acceleration distance, so that the motor can operate under the same power supply condition Down throws heavier objects with greater mass.

Description of drawings

Fig. 1 is a top view structural representation of the present invention;

Fig. 2 is the cross-sectional structure schematic diagram at A-A place in Fig. 1;

Fig. 3 is a partial side view structural representation of the present invention;

Fig. 4 is a schematic diagram of the front structure of the stator teeth located in the acceleration section of the front end;

Fig. 5 is a top view structural schematic diagram of stator teeth located in the acceleration section of the front end;

Figure 6 is a schematic side view of the stator teeth located in the front end acceleration section;

Fig. 7 is a front structural schematic view of the stator teeth located in the braking section at the tail end;

Fig. 8 is a top structural schematic diagram of stator teeth located in the braking section at the tail end;

Fig. 9 is a schematic side view of the stator teeth located in the braking section at the rear end.

illustration

1. Base; 101. Baffle; 2. Brake spring; 3. Stator teeth; 4. Permanent magnet mover; 41. Roller; 42. Roller; 401. Frame; 402. Permanent magnet; 5. Eddy current braking Device; 6. Control mechanism; 7. Iron yoke back plate; 71. Movement channel; 711. Front end acceleration section; 712. Tail end brake section; 72. Guide rail; 721. Guide rail brake spring; 8. Position detection device.

Detailed ways

The present invention will be further described in detail below in conjunction with specific embodiments and accompanying drawings.

As shown in Figure 1, Figure 2 and Figure 3, the throwing platform based on the permanent magnet linear motor of the present invention includes a base 1, two oppositely arranged iron yoke back plates 7, stator teeth 3, permanent magnet movers 4, The eddy current braking device 5 and the control mechanism 6, the iron yoke back plate 7 are fixed on the base 1, the base 1 is provided with a baffle plate 101, the baffle plate 101 is arranged at the tail end of the iron yoke back plate 7, and the baffle plate 101 is provided with More than one brake spring 2. Each iron yoke back plate 7 is installed with more than one row of stator teeth 3 along the height direction, and two stator teeth 3 at corresponding positions on different iron yoke back plates 7 form a group to form a double-sided permanent magnet linear motor. Moreover, the permanent magnet linear motor has only one effective stroke in one direction. The present invention is to make the permanent magnet linear motor into a platform for throwing heavy objects in a specific direction. The multiple rows of stator teeth 3 can effectively enhance the thrust to the permanent magnet mover 4 . The stator teeth 3 are wound with three-phase windings connected with the control mechanism 6. The three-phase windings are drawn out through the terminals and powered by the three-phase inverter bridge. The entire control mechanism 6 is controlled according to the control method of the traditional brushless DC motor. The permanent magnet mover 4 includes a frame 401 and a permanent magnet 402, the permanent magnet 402 is wrapped in the frame 401, and the object to be thrown is placed above the frame 401. The size of the permanent magnet 402 should match the three-phase winding on the stator tooth 3, that is, the two poles of the permanent magnet 402 correspond to the three-phase winding, and the depths of the two should be equal. The corresponding positions of the two iron yoke back plates 7 are provided with more than one guide rail 72, the side surface of the permanent magnet mover 4 is slid on the guide rail 72 through the roller 42, and the bottom surface of the permanent magnet mover 4 is slid on the guide rail 72 through the roller 41. On the base 1 , more than one guide rail brake spring 721 is provided at the tail end of the guide rail 72 .

The permanent magnet mover 4 is installed in the movement channel 71 formed between the two iron yoke back plates 7. Along the acceleration direction of the permanent magnet mover 4, the movement channel 71 is divided into a front end acceleration section 711 and a tail end braking section. Segment 712, the tail end braking segment 712 is equipped with an eddy current braking device 5. The motion channel 71 is the effective stroke of the linear motor, which refers to the total length of the linear motor from the starting end to the destination end of the object being thrown, and the direction is fixed at this moment. The front end acceleration section 711 of the effective stroke is used to accelerate the permanent magnet mover 4 and the object to be thrown; the tail end braking section 712 of the effective stroke mainly brakes the permanent magnet mover 4 through the eddy current braking device 5 . The length of the tail-end braking section 712 is determined by the quality and size of the permanent magnet mover 4, and the length of the tail-end braking section 712 is advisable to be no more than 20% of the total length of the effective stroke. Except using the eddy current braking device 5, It can also be supplemented by energy consumption braking, reverse braking, regenerative braking and other control methods, and through the guide rail brake spring 721 and the brake spring 2, the permanent magnet mover 4 can be reliably braked.

Referring to Fig. 4, Fig. 5 and Fig. 6, the stator teeth 3 located in the front acceleration section 711 are silicon steel laminated stator teeth, so as to prevent the eddy current from affecting the acceleration of the motor. Referring to Fig. 7, Fig. 8 and Fig. 9, the stator teeth 3 located in the braking section 712 at the tail end are solid iron stator teeth, and the solid iron stator teeth constitute the eddy current braking device 5, so as to make full use of the internal formation of solid iron. The braking force of the eddy current makes the permanent magnet mover 4 brake rapidly. During production, several sets of stator teeth 3 can be manufactured together, and installed on the iron yoke back plate 7 through fasteners. At the same time, the three-phase winding coils on each stator tooth 3 are wound separately and leave joints, and are set in After the stator teeth 3 are attached, the joints are welded together by brass, which can be connected in series or in parallel.

During the installation process of the entire motor, the first focus is the adjustment of the straightness. The straightness of the permanent magnet linear motor will directly affect the operation of the motor. The straightness can be adjusted by special equipment. The second key point is the process of loading the permanent magnet mover 4 into the middle of the stator teeth 3 on the two iron yoke back plates 7 . During the installation process, it must be ensured that the permanent magnet mover 4 is not attracted to the stator teeth 3 on either side, which can be achieved by padding non-magnetic materials on both sides. When the permanent magnets 402 are loaded into the frame 401, the upper and lower rows can be staggered by a certain distance to reduce the inherent cogging force of the permanent magnet linear motor.

After the entire motor is assembled, it can be powered on and run. Before operation, the object to be thrown is placed on the platform at the top of the frame 401 in the permanent magnet mover 4, and its left, right and rear three degrees of freedom are restricted. The motor is controlled according to the control method of an ordinary permanent magnet DC motor. When the position detection device 8 detects that the permanent magnet mover 4 reaches the tail end braking section 712 (eddy current braking section), it starts to perform braking, and energy consumption braking can be added. Reverse braking, regenerative braking and other methods cooperate with eddy current braking. After the permanent magnet mover 4 starts to brake, the thrown object is thrown out by inertia. After the permanent magnet mover 4 completes the effective stroke, it slowly returns to the starting point by adding a reverse phase sequence current, and waits for the next delivery.

During the braking process, it is mainly realized by the eddy current brake device 5 . The principle of eddy current deceleration is to use the eddy current generated by the conductor that cuts the magnetic force line in the electromagnetic field and its own resistance to generate Joule heat, so that the kinetic energy of the moving object is converted into heat energy, thereby realizing deceleration and braking. This braking method has no direct contact, no friction and no wear, and the braking force has a high value in a large speed range. Through analytical calculation and finite element numerical calculation, it can be known that the eddy current braking force has a monotonically increasing function relationship with the square root of the speed; the eddy current braking force will be greater than the rated thrust of the motor when the speed of the mover exceeds a certain value, that is, greater than the reverse braking force act as the main resistance. It can be seen that, by adopting the above-mentioned permanent magnet linear motor structure, the braking distance can be shortened by about half of the distance required by only using reverse braking, which greatly lengthens the acceleration distance of the permanent magnet linear motor.

The above descriptions are only preferred implementations of the present invention, and the protection scope of the present invention is not limited to the above-mentioned embodiments, and all technical solutions under the idea of the present invention belong to the protection scope of the present invention. It should be pointed out that for those skilled in the art, some improvements and modifications without departing from the principles of the present invention should also be regarded as the protection scope of the present invention.

Claims (7)

1. A throwing platform based on a permanent magnet linear motor, characterized in that: comprise a base (1), two iron yoke back plates (7), stator teeth (3), permanent magnet movers (4) that are arranged oppositely ), an eddy current braking device (5) and a control mechanism (6), the iron yoke backboard (7) is fixed on the base (1), and each iron yoke backboard (7) is installed along the height direction There are more than one row of stator teeth (3), and two stator teeth (3) at corresponding positions on different iron yoke back plates (7) form a group, and the stator teeth (3) are wound with a control mechanism ( 6) Connected three-phase windings, the permanent magnet mover (4) is installed in the movement channel (71) formed between two iron yoke back plates (7), and moves along the permanent magnet mover (4) The acceleration direction of the motion channel (71) is divided into a front end acceleration section (711) and a tail end braking section (712), and an eddy current braking device (5) is installed on the tail end braking section (712); The permanent magnet mover (4) includes a frame (401) and a permanent magnet (402), the permanent magnet (402) is wrapped in the frame (401), and the object to be thrown is placed above the frame (401) , the size of the permanent magnet (402) matches the three-phase winding on the stator tooth (3), that is, the depth of the two is equal; the stator tooth (3) located in the front acceleration section (711) is a silicon steel laminated stator tooth, The stator teeth (3) located in the braking section (712) at the tail end are solid iron stator teeth, and the solid iron stator teeth constitute an eddy current braking device (5). 2. The throwing platform based on permanent magnet linear motor according to claim 1, characterized in that: the corresponding positions of the two iron yoke back plates (7) are provided with more than one guide rail (72), the The side of the permanent magnet mover (4) is slid on the guide rail (72). 3. The throwing platform based on permanent magnet linear motor according to claim 2, characterized in that: the side of the permanent magnet mover (4) is provided with rollers (42), and the rollers (42) slide Set on the guide rail (72). 4. The throwing platform based on a permanent magnet linear motor according to claim 2, characterized in that: the bottom surface of the permanent magnet mover (4) is slid on the base (1) through rollers (41). 5. The throwing platform based on a permanent magnet linear motor according to claim 2, characterized in that: more than one guide rail braking spring (721) is provided at the tail end of the guide rail (72). 6. The throwing platform based on permanent magnet linear motor according to claim 1 or 2 or 3 or 4 or 5, characterized in that: the base (1) is provided with a baffle (101), the baffle (101) is arranged at the tail end of the iron yoke back plate (7), and more than one brake spring (2) is arranged on the baffle plate (101). 7. The throwing platform based on permanent magnet linear motor according to claim 1 or 2 or 3 or 4 or 5, characterized in that: the control mechanism (6) is connected with a mover (4) for detecting the permanent magnet The position detecting device (8) of moving position is connected.

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