CN111486264A - Electrically excited bidirectional rotary electromagnet with horizontal moment-corner characteristic - Google Patents

Abstract

The electric excitation type bidirectional rotary electromagnet with the horizontal moment-corner characteristic is characterized in that a rotor and an output shaft are installed in a stator. The left stator yoke iron and the right stator yoke iron in the semi-square shape are spliced into a square stator, a stator magnetic pole extends out of a corner of each stator yoke iron along an angular bisector, and the four stator magnetic poles are distributed on the diagonal of the square frame shape at intervals of 90 degrees. The middle parts of the left and right stator yokes are provided with control coils to form control magnetic flux; the left and right stator iron yokes have excitation coils on their upper and lower sides to form a bias magnetic field. The rotor is X-shaped, four large teeth are distributed at positions corresponding to the stator teeth in the circumferential direction, each large tooth end face comprises a circular arc-shaped tooth face and a rectangular face, and the tooth face and the radial end face of the stator magnetic pole form a radial air gap. The rectangular surface is positioned at the end part of the tooth surface of the large tooth and forms an axial air gap with the side surface of the stator magnetic pole. The rectangular surfaces of the two large teeth corresponding to the two stator poles of the same stator yoke are located at the ends of the tooth surfaces which are far away from each other.

Description

Electrically excited bidirectional rotary electromagnet with horizontal moment-corner characteristic

Technical Field

The invention belongs to an electro-mechanical converter for an electro-hydraulic servo/proportional rotary valve in an electro-hydraulic servo/proportional control system, and particularly relates to a bidirectional rotary torque motor with a horizontal torque-rotation angle characteristic.

Background

The rotary valve is a reversing valve which changes the relative position of a valve core and a valve sleeve by utilizing rotary motion to change a flow path in the rotary valve and finally realizes the opening and closing or reversing of the flow path. The rotary valve can be driven manually, mechanically or directly by an electric motor, a motor and a rotary electromagnet to achieve precise servo/proportional control. Compared with a slide valve or a cone valve, the rotary valve has the advantages of high reliability, simple structure, high working frequency, strong oil pollution resistance and the like, can be widely applied to hydraulic systems of high-speed switching, high-speed excitation and high-speed reversing, and can obtain rated flow which is larger than that of a multi-stage slide valve by a single-stage rotary valve particularly when the number of throttling grooves of a valve core and a valve sleeve is large. However, in the prior electro-hydraulic servo/proportional control system, the rotary valve is far less widely used than the slide valve. The reason is that firstly, the throttling groove/window of the rotary valve is complex to process, secondly, the rotary electromagnet for driving the rotary valve is more difficult to obtain the proportion control characteristic than the direct-acting type proportion electromagnet, the latter adopts a magnetism isolating ring structure, a magnetic circuit is divided into two paths of axial and radial at the magnetism isolating ring during excitation, the horizontal stroke-thrust characteristic required by the proportion control can be obtained after synthesis, although the welding of a magnetism conducting sleeve is more complicated, the problem is not big for large-scale automatic production, and the rotary electromagnet always needs to carry out special optimization design on the shapes of stator teeth and rotor teeth to obtain the flatter moment-corner characteristic, thereby greatly limiting the practical application of the rotary electromagnet.

In order to popularize and apply the rotary valve in an electro-hydraulic servo/proportional system, people make a great deal of research on the optimization of the magnetic circuit topological structure and the moment angle characteristic of the rotary electromagnet. The torque motor is widely applied to nozzle flapper valves and jet pipe servo valves, proportional position control characteristics can be obtained through reasonable design of an elastic element, but a large working angle is difficult to obtain due to the fact that a magnetic circuit of the torque motor is based on an axial air gap. The improved torque motor based on the radial working air gap, which is proposed by Montagu of the American general detection company, has the advantages that the working rotation angle range is further expanded, and the torque motor has positive electromagnetic rigidity, so that the proportional position control characteristic can be obtained without adding an elastic element. To obtain a flat torque angle characteristic curve, Fumio of Hitachi designs the permanent magnet shape of the rotor of the moving magnet torque motor, and cuts grooves along the radial direction on the pole surface and fills non-magnetic conductive material, so as to compensate the torque pulsation accompanied by the rotation of the rotor. In the permanent magnet torque motor designed by the shin-tou-shui-lang of the company denso, two magnetic poles formed by discrete permanent magnets are asymmetrically arranged on the outer side of a rotating shaft in a way of half a magnetic pole angle difference, so that torque pulsation caused by the periphery of a polygonal magnetic pole is compensated, and a stable torque-corner characteristic is obtained. The electric excitation torque motor developed by Zhang Guangqiong of Zhejiang university, etc. specially designs the shapes of the stator magnetic pole and the rotor pole surface, and changes the torque angle characteristic of the motor by controlling the magnetic flux saturation degree at the tip of the stator magnetic pole shoe. The trekker et al propose a moving-magnet type rotary proportional electromagnet based on a radial working air gap, which is based on a differential magnetic circuit and has positive electromagnetic stiffness, but the structure is complicated, and the moving-magnet type rotary proportional electromagnet is not beneficial to industrial application and large-scale batch production.

Disclosure of Invention

In order to overcome the defects that the existing rotary electromagnet is difficult to obtain the horizontal moment-corner characteristic, complex in structure and not beneficial to industrial application and large-scale batch production, the invention provides the bidirectional rotary electromagnet which is based on the mixed air gap, has the horizontal moment-corner characteristic and is simple in structure.

The basic principle of the invention is as follows: the common working air gaps in the electro-mechanical converter comprise a radial air gap and an axial air gap, the radial air gap can have a larger working rotation angle, but with the increase of the misalignment angle (the stator and the rotor are gradually aligned), the output torque can be reduced, namely the slope of a torque angle characteristic curve is negative; the axial air gap working range is narrower, but the output torque increases along with the increase of the misalignment angle, namely the slope of the torque angle characteristic curve is positive. Therefore, the working air gap is divided into two parts, the main working air gap is a radial air gap, and an axial air gap is added on the basis of the radial air gap. The moments generated by the radial air gap and the axial air gap are mutually modulated, a moment-angle characteristic curve close to the horizontal can be obtained through reasonable parameter optimization, and the proportional position control characteristic can be obtained through the addition of a linear spring.

The technical scheme adopted by the invention for solving the technical problems is as follows:

the electrically excited bidirectional rotary electromagnet with horizontal moment-corner characteristic has stator with front and back sides installed separately on the front end cover 1 and the back end cover 2, rotor 5 installed inside the stator, output shaft 8 installed on the rotor 5, and two ends of the output shaft 8 installed separately on the front end cover 1 and the back end cover 2. The stator comprises a left stator yoke 7 and a right stator yoke 3, the left stator yoke 7 and the right stator yoke 3 are spliced into a square frame, a stator convex tooth extends out of the corner of each stator yoke along an angular bisector, the stator convex teeth form stator magnetic poles, the left stator yoke 7 is provided with a first stator magnetic pole and a second stator magnetic pole, the right stator yoke 3 is provided with a third stator magnetic pole and a fourth stator magnetic pole, and the four stator magnetic poles are distributed on the diagonal line of the square frame at intervals of 90 degrees, so that the structure of the electromagnet is compact, a larger winding space can be provided for a control coil, the control magnetic flux is increased, and the output torque is improved. Symmetrical notches are respectively formed in the middle of the left stator yoke 7 and the right stator yoke 3, and a first control coil 9 and a second control coil 4 are respectively wound to form control magnetic flux; the upper side and the lower side of the left stator yoke and the right stator yoke are provided with symmetrical notches which are spliced and then wound with a first excitation coil 11 and a second excitation coil 6, and the first excitation coil 11 and the second excitation coil 6 form a bias magnetic field through the left stator yoke, the right stator yoke and the rotor 5.

The rotor 5 is in an X shape, four large teeth are distributed at the positions corresponding to the stator teeth in the circumferential direction, the end face of each large tooth is composed of two parts, the first part is an arc-shaped tooth face 51, and a radial air gap is formed between the first part and the radial end face of the stator magnetic pole. The second portion is a rectangular face 52 at the end of the face of the large tooth that forms an axial air gap with the side of the stator pole. Rectangular surfaces 52 of two large teeth corresponding to two stator poles of the same stator yoke are located at the ends of the tooth surface 51 that are away from each other. The front end cover 1, the rear end cover 2 and the output shaft 8 are made of non-magnetic metal materials, and the rotor 5, the left stator yoke 7 and the right stator yoke 3 are made of high-magnetic-permeability metal soft magnetic materials.

The common working air gaps in the electro-mechanical converter comprise a radial air gap and an axial air gap, the radial air gap can have a larger working rotation angle, but with the increase of the misalignment angle (the stator and the rotor are gradually aligned), the output torque can be reduced, namely the slope of a torque angle characteristic curve is negative; the axial air gap working range is narrower, but the output torque increases along with the increase of the misalignment angle, namely the slope of the torque angle characteristic curve is positive. Therefore, the working air gap is divided into two parts, the main working air gap is a radial air gap, and an axial air gap is added on the basis of the radial air gap. The moments generated by the radial air gap and the axial air gap are mutually modulated, a moment-angle characteristic curve close to the horizontal can be obtained through reasonable parameter optimization, and the proportional position control characteristic can be obtained through the addition of a linear spring.

The magnetic flux under the air gap of the rotating electromagnet consists of two parts, one part is bias magnetic flux generated by the exciting coil, the other part is control magnetic flux generated by the control coil, and the two magnetic fluxes are mutually modulated to realize the normal work of the electromagnet. When the electromagnet is not electrified, the air gap magnetic flux of the electromagnet is only dependent on the bias magnetic flux of the excitation coil, the position relation of the stator and the rotor under the four magnetic poles of the electromagnet is the same, the magnetic flux passing through the four working air gaps is the same, and the rotor is in an initial balance state. When current flows through the control coil, the generated control magnetic flux interacts with the bias magnet of the exciting coil to generate output torque. The magnitude of the torque can be adjusted through the magnitude of the exciting current and the control current, the direction of the torque can also be adjusted through the directions of the exciting current and the control current, and theoretically, the maximum working angle of the electromagnet is the radian occupied by each annular pole face of the rotor.

The invention has the following beneficial effects:

1. a hybrid working air gap is used to achieve a horizontal torque-turn angle characteristic. The working air gap is divided into two parts, the main working air gap is a radial air gap, and an axial air gap is added on the basis of the radial air gap. The moments generated by the radial air gap and the axial air gap are mutually modulated, a moment-angle characteristic curve close to the horizontal can be obtained through reasonable parameter optimization, and the proportional position control characteristic can be obtained through the addition of a linear spring.

2. Simple structure and low cost. Compared with other rotary proportional electromagnets, the rotary proportional electromagnet has the advantages of small number of parts, easiness in processing and assembling, low manufacturing cost and contribution to industrial practical application and large-scale batch production.

3. The response speed is high. Compared with other cylindrical structures of the rotary proportional electromagnet rotor, the rotor of the scheme provided by the invention is of an X-shaped structure, the rotational inertia is small, and higher dynamic response speed is favorably obtained.

4. The magnitude and direction of the output torque are convenient to control. The bias flux formed by the permanent magnet is difficult to adjust from the outside, and it is extremely difficult to control the magnetic field thereof. The permanent magnet may produce irreversible demagnetization when the temperature is too high or when the mechanical shock is severe, and the performance of the torque motor is reduced. And the adoption of electric excitation facilitates the adjustment of bias magnetic flux, so that better torque-corner characteristics are obtained after the modulation of the bias magnetic flux and the control magnetic flux.

Drawings

FIG. 1 is a schematic view of the present invention;

FIG. 2 is an assembly schematic of the present invention;

FIG. 3 is a schematic view of the stator structure of the present invention;

FIG. 4 is a schematic view of the end cap construction of the present invention;

FIG. 5 is a schematic view of a rotor structure of the present invention;

FIG. 6 is a schematic view of a rotor shaft configuration of the present invention;

FIG. 7 is a graphical illustration of the torque angle characteristics of the radial air gap, axial air gap, and hybrid air gap;

FIG. 8 is a schematic diagram of the working principle of the present invention;

FIG. 9 is a schematic diagram of the working principle of the present invention, wherein the control coil is applied with a forward current;

fig. 10 is a schematic diagram illustrating the operation of the present invention, wherein the control coil is energized with a reverse current.

Detailed Description

The invention is further described below with reference to the accompanying drawings.

Referring to fig. 1 to 7, in an electrically excited bidirectional rotary electromagnet having a horizontal moment-rotation angle characteristic, front and rear sides of a stator are respectively mounted on a front end cover 1 and a rear end cover 2, a rotor 5 is mounted in the stator, an output shaft 8 is mounted on the rotor 5, and both ends of the output shaft 8 are respectively mounted on the front end cover 1 and the rear end cover 2. The stator comprises a left stator yoke 7 and a right stator yoke 3, the left stator yoke 7 and the right stator yoke 3 are spliced into a square frame, a stator convex tooth extends out of the corner of each stator yoke along an angular bisector, the stator convex teeth form stator magnetic poles, the left stator yoke 7 is provided with a first stator magnetic pole and a second stator magnetic pole, the right stator yoke 3 is provided with a third stator magnetic pole and a fourth stator magnetic pole, and the four stator magnetic poles are distributed on the diagonal line of the square frame at intervals of 90 degrees, so that the structure of the electromagnet is compact, a larger winding space can be provided for a control coil, the control magnetic flux is increased, and the output torque is improved. Symmetrical notches are respectively formed in the middle of the left stator yoke 7 and the right stator yoke 3, and a first control coil 9 and a second control coil 4 are respectively wound to form control magnetic flux; the upper side and the lower side of the left stator yoke and the right stator yoke are provided with symmetrical notches which are spliced and then wound with a first excitation coil 11 and a second excitation coil 6, and the first excitation coil 11 and the second excitation coil 6 form a bias magnetic field through the left stator yoke, the right stator yoke and the rotor 5.

The rotor 5 is X-shaped, four large teeth are arranged along the circumferential direction corresponding to the stator teeth, each large tooth end surface is composed of two parts, the first part is an arc tooth surface 51, and a radial air gap is formed between the arc tooth surface and the stator magnetic pole. The second portion is a rectangular surface 52 at the end of the large tooth annular surface that forms an axial air gap with the stator pole side surface. Rectangular surfaces 52 of two large teeth corresponding to two stator poles of the same stator yoke are located at the ends of the tooth surface 51 that are away from each other. The front end cover 1, the rear end cover 2 and the output shaft 8 are made of non-magnetic metal materials, and the rotor 5, the left stator yoke 7 and the right stator yoke 3 are made of high-magnetic-permeability metal soft magnetic materials.

As shown in fig. 8, when the first control coil 9 and the second control coil 4 are not energized, the air gap flux thereof depends only on the bias flux of the excitation coil, and at this time, the stator-rotor positional relationship under the four poles of the electromagnet is the same, that is, the stator pole and the respective rotor tooth are staggered by the same arc surface, the radial air gap and the axial air gap in the four poles are the same, and the rotor 5 is at the initial position of the middle position.

When the first control coil 9 and the second control coil 4 are simultaneously supplied with the forward currents as shown in fig. 9, the control magnetic fields of the control coils and the bias magnetic fields of the excitation coils are overlapped with each other in the same direction under the working air gaps of the first magnetic pole g1 and the fourth magnetic pole g4, and the air gap magnetic flux is increased; the control magnetic field of the control coil under the working air gap of the second magnetic pole g2 and the third magnetic pole g3 is opposite to the bias magnetic field of the excitation coil and offset each other, the air gap flux is reduced, the rotor 5 rotates anticlockwise under the action of electromagnetic torque, and the torque generated by the radial air gap and the axial air gap is modulated each other, so that the electromagnet obtains a nearly horizontal torque angle characteristic, the magnitude of the output torque can be adjusted by controlling the magnitude of current, and when the output torque is matched with a linear spring to use, a position control effect proportional to the current can be obtained.

When the first control coil 9 and the second control coil 4 are simultaneously supplied with the reverse currents as shown in fig. 10, the control magnetic fields of the control coils and the bias magnetic fields of the excitation coils are overlapped with each other in the same direction under the working air gaps of the second magnetic pole g2 and the third magnetic pole g3, and the air gap magnetic flux is increased; the control magnetic field of the control coil under the working air gap of the first magnetic pole g1 and the fourth magnetic pole g4 is opposite to the bias magnetic field of the excitation coil and mutually offset, the air gap flux is reduced, the rotor 5 rotates clockwise under the action of electromagnetic torque, and the torque generated by the radial air gap and the axial air gap is mutually modulated, so that the electromagnet obtains a nearly horizontal torque angle characteristic, the magnitude of the output torque can be adjusted through controlling the magnitude of current, and when the control coil is matched with a linear spring to use, a position control effect proportional to the current can be obtained.

The embodiments described in this specification are merely illustrative of implementations of the inventive concept and the scope of the present invention should not be considered limited to the specific forms set forth in the embodiments but rather by the equivalents thereof as may occur to those skilled in the art upon consideration of the present inventive concept.

Claims (1)

1. The electric excitation type bidirectional rotating electromagnet with the horizontal moment-corner characteristic is characterized in that the front side and the rear side of a stator are respectively installed on a front end cover (1) and a rear end cover (2), a rotor (5) is installed in the stator, an output shaft (8) is installed on the rotor (5), and two ends of the output shaft (8) are respectively erected on the front end cover (1) and the rear end cover (2); the stator is composed of a left stator yoke (7) and a right stator yoke (3), the left stator yoke (7) and the right stator yoke (3) in a half-square shape are spliced into a square frame shape, a stator convex tooth extends out of a corner of each stator yoke along an angular bisector, the stator convex tooth forms a stator magnetic pole, the left stator yoke (7) is provided with a first stator magnetic pole and a second stator magnetic pole, the right stator yoke (3) is provided with a third stator magnetic pole and a fourth stator magnetic pole, and the four stator magnetic poles are distributed on a diagonal line of the square frame shape at an angle of 90 degrees, so that the electromagnet is compact in structure, and meanwhile, a larger winding space can be provided for a control coil to increase control magnetic flux, and output torque is improved; symmetrical notches are respectively formed in the middle of the left stator yoke (7) and the right stator yoke (3), and a first control coil (9) and a second control coil (4) are respectively wound to form control magnetic flux; the upper side and the lower side of the left stator iron yoke and the right stator iron yoke are both provided with symmetrical notches, and the first excitation coil (11) and the second excitation coil (6) are wound after being spliced, and the first excitation coil (11) and the second excitation coil (6) form a bias magnetic field through the left stator iron yoke, the right stator iron yoke and the rotor (5);

the rotor (5) is X-shaped, four large teeth are distributed at the positions corresponding to the stator teeth in the circumferential direction, the end face of each large tooth consists of two parts, the first part is an arc-shaped tooth face (51), and a radial air gap is formed between the first part and the radial end face of the stator magnetic pole; the second part is a rectangular surface (52) which is positioned at the end part of the tooth surface of the big tooth and forms an axial air gap with the side surface of the stator magnetic pole; rectangular surfaces (52) of two large teeth corresponding to two stator magnetic poles of the same stator yoke are positioned at one ends, far away from each other, of the tooth surfaces (51); the front end cover (1), the rear end cover (2) and the output shaft (8) are made of non-magnetic metal materials, and the rotor (5), the left stator yoke iron (7) and the right stator yoke iron (3) are made of high-magnetic-permeability metal soft magnetic materials.

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