RU2750646C1 - Linear valve electric motor - Google Patents

Abstract

FIELD: mechanical engineering.

SUBSTANCE: invention relates to the field of mechanical engineering, in particular to the design of the magnetic system of a linear valve electric motor (LVEM). The stator bore is formed by the toothed surface of the core, in which one part of the teeth is made of soft magnetic material, and the second part of the teeth is made of non-magnetic material. The teeth made of soft magnetic and non-magnetic materials are displaced in the longitudinal and radial directions, along the axis of symmetry of the stator, forming a helix of the tooth screw made of soft magnetic material, the inter-turn space of which is filled with teeth of non-magnetic material.

EFFECT: increased manufacturability, increased power density while reducing the size of the installation.

7 cl, 4 dwg

Description

The claimed invention relates to the field of mechanical engineering, in particular, to linear valve electric motors, namely, to the structural implementation of the magnetic system of the linear valve motor (LVED).

It is known from the prior art that today linear electric motors have found application in many industries, in particular in the oil industry, where they are effectively used as drives for submersible plunger pumps. Of patents for inventions: UA115401 from 10/25/2017, UA118287 from 12/26/2018, UA118520 from 25/01/2019, RU2615775 from 11/04/2017, as well as applications for inventions WO / 2019/108160 from 11/07/2018, US20170284177A1 from 05/10/2017 are known submersible pumping units with a three-phase linear valve electric motor, where a movable part (slider) is installed in the stator bore, which is made of permanent magnets and is set in motion under the influence of the running magnetic field of the stator.

Also known from the prior art are magneto-screw and spiral stepping motors, where the movable part performs translational movement with simultaneous spiral rotation. Below are examples of known technical solutions. The main advantages of this type of motors are the high power of the electric motor, as well as the ability to accurately position the moving part.

Along with these advantages, the known solutions of magneto-screw motors also have disadvantages, such as: the presence of parasitic rotation of the rotor during translational motion, excessive heating, the impossibility of using it in high-frequency motors, the many details and complexity of assembly of the structure.

The claimed invention is intended to solve the known disadvantages of the prior art.

A contactless magnetic screw transmission is known from the patent for invention of the Russian Federation No. 2183773 dated 20.02.2002. The known invention is intended to create an ultra-precise linear drive in machine tools, metrology, optics and electronics industry.

The non-contact magnetic screw transmission contains a screw 1 and a nut 2, including a permanent magnet 3, made in the form of a ring with the magnetization direction along its axis, installed between the magnetic cores 14 with pole pieces 4. On the screw 1 and pole pieces 4, a fine-modular thread is made, the grooves of which are filled solid non-magnetic material flush with the crests of the threads. The screw 1 and the nut 2 interact with each other through a radial gap, into which, through the aerostatic throttle assemblies 12 installed on the edges of the nut 2, a compressed fluid medium from an external source is supplied through the supply channels 13. Rings made of porous material, jets, calibrated slot holes can be used as aerostatic throttle elements 12. In the described invention, the kinematic accuracy and rigidity of the transmission are increased with small overall dimensions.

The disadvantages of the known technical solution include the complexity of the design, which complicates its application in various industries. Also, a disadvantage can be considered the presence of a parasitic rotational movement, which reduces the efficiency of the system.

Also from the application for FROM WO2016173293A1 dated 03.11.2016 a stator-rotor mechanism of a spiral stepper motor is known. The rotor contains a central shaft (1) and a plurality of rotor blocks (2), and the rotor blocks (2) are continuously or evenly spaced apart on the circumference of the central shaft (1). The stator contains a plurality of stator blocks (3), a barrier layer (5) and a cover (4), and the stator blocks (3) and the rotor blocks (2) are located in the radial direction at the same distance from each other. In a given direction, the axial width of the working surface of the stator unit (3) is equal to the width of the axis of the rotor unit (2). The stator blocks are aligned with the rotor blocks. When the engine is running, a dynamic spiral magnetic field is created between the stator blocks (3) and the rotor blocks (2), and under the action of the spiral magnetic field, rectilinear and circular motion without friction occurs between the stator (3) and rotor (2) blocks. According to the spiral stepper motor, one of the two parts can move in a circular motion and the other in a rectilinear motion, or one part can simultaneously move in a circular motion and a rectilinear motion.

The disadvantages of the described technical solution include the complexity of the design and the presence of parasitic rotational motion of the rotor, which reduces the efficiency of the system.

From patent for invention JP3399368 a helical electric motor is known in which the stator contains a spiral core made of magnetic material with a winding installed in the spiral cavity. These windings are located in the magnetic field of the permanent magnets of the rotor installed between the turns of the stator spiral.

The stator core is formed from a pre-assembled laminated cylinder of sheet steel, in which a spiral opening is cut. Stator winding coils are installed on the walls of the spiral turns. A rotor screw with permanent magnets is installed between the turns of the stator spiral. When the magnetic fields of the stator winding and the permanent magnets of the rotor interact, the said rotor performs translational motion with simultaneous rotation along the trajectory of the stator spiral.

The disadvantages of the described technical solution include the complexity of the design and manufacturing technology. The presence of rotational motion leads to a decrease in efficiency and power density.

We take the indicated technical solution as the closest analogue.

The technical problem to be solved by the claimed technical solution is the creation of a linear valve electric motor (LVED) of a simplified design with reduced dimensions.

The technical result achieved from the implementation of the claimed invention is to simplify the design of a linear valve electric motor, improve manufacturability, increase power density while reducing the size of the installation.

The essence of the claimed invention lies in the fact that the bore of the stator is formed by the toothed surface of the core, in which one part of the teeth is made of soft magnetic material, and the second part of the teeth is made of non-magnetic material. The teeth of a soft magnetic and non-magnetic material are displaced in the longitudinal and radial directions, along the axis of symmetry of the stator, forming a helix of a toothed screw made of a soft magnetic material, the inter-turn space of which is filled with teeth of a non-magnetic material.

The toothed screw made of soft magnetic material is made with the number of starts equal to n, where n≥1.

The teeth of a soft magnetic material are displaced along the length of the stator in the radial direction by a multiple of an integer tooth division.

The stator winding is laid in slots made of soft magnetic and non-magnetic material.

The stator core is made of a combined material including isotropic electrical steel with polymer inserts.

The stator winding contains "p" pairs of poles, where p≥1 while the number of revolutions of the magnetic field for one period of the sinusoid m≥1 / p.

The essence of the claimed invention is explained, but not limited to the following graphic materials:

Fig. 1 - magnetic system of LVED;

Fig. 2 - stator of LVED;

Fig. 3 is an embodiment of the stator core of the LVED;

Fig. 4 - the position of the plates of the stator core of the LVED;

The claimed invention can be implemented in various technological processes and mechanisms where there is a need to provide a controlled translational movement of mechanisms with a high positioning accuracy of moving parts, in particular, in medicine, robotics, machine tools, mechanical engineering.

The claimed invention combines the advantages of linear motors known from the prior art.

According to one of the possible embodiments of the invention, the LVED 1 consists of a stator 2 containing a magnetic circuit (core) 3 made of a magnetically soft material and a three-phase winding 4 laid in the grooves 5 of the core. Also, the specified LVED contains a movable part (slider) 6 made with constant magnetic resistance. The slider performs reciprocating movements relative to the stator 2. The slider 6 (Fig. 1) is formed from a set of permanent magnets 7 with magnetic field concentrators 8 between them.

An embodiment without magnetic field concentrators is also possible, whereby the magnets 7 can be installed close to each other, and the magnetic field vectors are concentrated between adjacent magnets.

Permanent magnets 7 are installed in series with periodic reversal of the SN polarity of one magnet with respect to the previous NS. In one of the possible embodiments, the slider 6 is made of a rod 9 with magnets 7 installed on a threaded connection, while the permanent magnets 7 are made in the form of rings and are installed on the surface of the rod 9, this shape of the magnets makes it possible to provide constant magnetic resistance. The concentrators 8 have a larger radial dimension in relation to the magnets 7 and are installed periodically, separating the magnets. The hubs 8 provide the positioning of the slider 6 relative to the stator 2, limiting the radial movement and form a constant non-magnetic gap 10 between the bore of the stator 2 and the elements of the slider. In the above embodiment, the slider 6 is installed inside the stator bore 2. It is also possible that the stator bore is located inside the slider, while the slider rod is hollow. In each of the embodiments, the stator bore is installed in the magnetic field of the permanent magnets of the slider.

In the illustrated embodiment of the invention, the stator 2 consists of a magnetic circuit (core). Plates 11 (figure 2, 3) of the stator core 2 are made of a special shape where part of the teeth 12 are reduced in size in relation to the rest of the teeth. The enlarged teeth 13 are combined into groups 14 (Fig. 3). The number of groups of teeth is equal to the number of starts of the tooth screw. The number of starts of the gear screw is equal to n, where n≥1, while the input teeth of the core are displaced relative to each other in the radial direction.

The bore of the stator 15 is formed by the toothed surface of the core, in which one part of the teeth 13 is made of a soft magnetic material, and the second part of the teeth 16 is made of a non-magnetic material. The teeth made of soft magnetic and non-magnetic material are displaced in the longitudinal and radial directions, along the axis of symmetry of the stator, forming a helix of the tooth screw 17 made of soft magnetic material, the inter-turn space 18 of which is filled with teeth 15 of non-magnetic material. The described embodiment of the technical solution makes it possible to form in the turn-to-turn space 18 a non-magnetic helical gap of the stator core.

Thus, the stator core 2 is made of a combined material including isotropic electrical steel with polymer inserts. Polymer inserts fill the space 18 formed when the teeth 13 are displaced in the radial and longitudinal direction relative to the axis of symmetry of the stator. The teeth of one plate or a group of such plates are displaced in the radial direction with a shift along the length of the stator relative to the teeth of the next plate or group of plates by an amount k multiple of an integer tooth division (Fig. 4).

Figure 4 shows the trajectory 20 of changing the position of the groups of 14 teeth in space to the position 14 + k. The position of the stator teeth made of soft magnetic material is repeated periodically with an offset along the stator length by an amount equal to the distance between the nearest opposite poles of the slider.

The described design makes it possible to ensure the concentration of the stator magnetic field on the helix of the toothed screw, while one pair of poles SN of the slider, there is at least one revolution of the screw 17 of the stator 2.

The multi-threaded screw allows to increase the specific power of the motor and the efficiency, due to the constancy of the stator magnetic field.

In the grooves 5 of a soft magnetic and non-magnetic material between the teeth 13,16 laid a three-phase winding 4 of the stator 2, where the phases are connected in a star. In an embodiment without a zero point, the phase connection can be delta-connected. In the described embodiment, the stator winding is distributed, with the winding being extended. This technical solution increases the efficiency of interaction between the magnetic fields of the stator and the slider, and also reduces the higher harmonics of the current. Also, the grooves 5 of the stator are covered with an insulating material 19, such as heat shrink tubing, providing protection against insulation breakdown.

The stator winding 4 contains "p" pairs of poles, where p≥1, while the number of revolutions of the stator magnetic field in one period of the sinusoid is equal to m, where m = 1 / p. In this embodiment of the invention, the number of revolutions of the stator magnetic field per period decreases with an increase in the number of pole pairs. This embodiment makes it possible to create a low-speed linear electric motor with a mains frequency of 50 Hz.

A non-magnetic helical gap formed by the teeth 16 of a non-magnetic material, made in the form of polymer inserts repeating the shape of the teeth from a magnetically soft material, is associated with a non-magnetic gap 10 between the slider 6 and the stator 2. On the teeth 13 (figure 2) of the said screw 17, the stator magnetic field is concentrated ... The constant radial non-magnetic gap 10 between the stator teeth 13, 16 and magnets with concentrators 8 of the magnetic field of the slider 6 provides the same radial magnetic resistance at each point of the slider surface, which does not allow the magnetic flux of the stator 2 to rotate the slider 6 relative to its longitudinal axis. This solution allows you to completely eliminate the rotational movement of the slider 6 and leaves only the translational movement, which increases the efficiency of the engine. Also, high accuracy of motor control, in particular, the positioning accuracy of the slider 6 is provided by reducing the size of the pair of poles τ (slider magnets), where τ is taken taking into account the frequency of the supply network and the speed of the slider.

The implementation of the described invention leads to the achievement of the claimed technical result, providing a simplified design of a linear valve electric motor, an increase in manufacturability, allowing the stator to be assembled using standard technological equipment. Also, the declared principle and technology of assembly of a linear electric motor allows to increase the specific power while reducing the dimensions of the installation.

Claims (7)

1. The linear valve motor includes a fixed part of the stator and a movable element made in the form of a slider, the said stator contains a core and a three-phase winding laid in the grooves of the core, while the slider is made of a set of permanent magnets with constant magnetic resistance, and the stator bore is installed in a magnetic the field of permanent magnets of the slider differs in that the bore of the stator is formed by the toothed surface of the core, in which one part of the teeth is made of soft magnetic material, and the second part of the teeth is made of non-magnetic material, the teeth of soft magnetic and non-magnetic materials are displaced in the longitudinal and radial directions, along the axis of symmetry of the stator, forming a helix of a toothed screw from a magnetically soft material, the inter-turn space of which is filled with teeth of a non-magnetic material. 2. The linear valve motor according to claim 1 is characterized in that the toothed screw made of soft magnetic material is made with the number of starts equal to n, where n≥1, while the teeth are displaced relative to each other in the radial direction. 3. The linear valve motor according to claim 1 is characterized in that the position of the teeth of the stator core made of soft magnetic material is repeated periodically with an offset along the stator length by an amount equal to the distance between the nearest opposite poles of the slider. 4. The linear valve motor according to claim 1 is characterized in that the teeth made of a soft magnetic material are displaced along the length of the stator in the radial direction by an amount that is a multiple of an integer tooth division. 5. The linear valve motor according to claim 1 is characterized in that the stator winding is laid in grooves formed by teeth of soft magnetic and non-magnetic materials. 6. The linear valve motor according to claim 1 is characterized in that the stator core is made made of a combined material including isotropic electrical steel with polymer inserts. 7. The linear valve motor according to claim 1 is characterized in that the stator winding contains "p" pairs of poles, where p≥1, while the number of turns of the stator magnetic field for one period of the sinusoid is equal to m, where m = 1 / p.

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