High-speed electromagnet with rapid demagnetizing electromagnetic coil

Abstract

The invention provides a high-speed electromagnet with a rapid demagnetizing electromagnetic coil. The high-speed electromagnet comprises a yoke, and a coil assembly is installed in the yoke; the coil assembly comprises a main coil and a degaussing coil, and magnetic fluxes generated by the main coil and the degaussing coil are the same in size but opposite in direction; and a circuit on-off device is arranged on a power supply line of the degaussing coil. The main coil and the degaussing coil form a closed loop, residual current of the main coil flows into the degaussing coil through the loop, the current disappearance speed of the main coil is increased, residual magnetic flux of the main coil can be counteracted by magnetic flux generated by the degaussing coil, residual magnetic field energy around the armature is rapidly consumed, electromagnetic attraction is rapidly reduced, and the electromagnetic attraction is rapidly reduced. The purpose of quick response of the electromagnet is achieved; meanwhile, the induced electromotive force generated in the electromagnetic coil during power failure is beneficially utilized, and the impact of the induced electromotive force on an external circuit is eliminated, so that the external circuit and control requirements of the electromagnet are simplified, and the application field of the high-speed electromagnet is expanded.

Description

Technical Field

[0001] The invention relates to a high-speed electromagnet with a fast demagnetizing electromagnetic coil. Background Art

[0002] High-speed electromagnet is a key component of the drive control system (such as the engine gas valve). It receives control instructions to control the rapid start and shutdown of the electromagnet to achieve precise drive of the control system. Its dynamic response speed directly determines the control accuracy of the control system. The electromagnetic force and response characteristics of the high-speed electromagnet are complex systems affected by many factors. Its applications mainly involve military and civilian industries such as engines and aerospace.

[0003] High-speed electromagnets are generally direct-acting structures. Under the excitation of the power supply, they generate electromagnetic suction through the coil. Under the action of the electromagnetic suction, the drive shaft on the armature part overcomes the external load and the reaction force of the internal compression spring and moves a certain distance. When the armature plane fits the iron core plane, the action stops; after the coil is de-excited, the internal magnetic flux of the electromagnet gradually decays. When the electromagnetic suction is less than the combined force of the external load and the internal compression spring reaction force, the armature part is disengaged from the iron core attraction and moves to restore the initial state. At the moment when the electromagnet is powered off, the magnetic field will prevent the change of current and will generate an induced electromotive force several times the power supply electromotive force at both ends of the coil. When using electromagnets, measures need to be taken to prevent the induced electromotive force from impacting the external circuit. This type of product is mainly suitable for aerospace, valve drive and other fields, and is used for mechanical motion control of specific mechanisms. Therefore, the key indicators of this type of product are driving force and response speed.

[0004] At present, traditional electromagnet products mainly achieve the required electromagnetic force and response time by designing the structural dimensions of the core, armature, coil and other components to match the material properties; due to the characteristics that the current of the electromagnetic coil cannot change instantaneously after the power is turned off and will continue to store magnetic field energy, as well as the hysteresis phenomenon that the coercive force and magnetic induction intensity of the ferromagnetic material itself always lag behind the change of the magnetic field intensity, the electromagnet needs a certain time to complete the action, that is, the response characteristics of the product. In the aerospace field where volume and mass restrictions are extremely strict, the response time (millisecond level) and driving force of the electromagnet under the characteristics of existing materials can no longer meet the increasing control needs.

[0005] In addition, high-speed electromagnets usually have high power. When the power is off, due to the electromagnetic induction phenomenon, the changing magnetic field will generate a reverse electromotive force in the coil to prevent the change of current. The value of the induced electromotive force generated is several times or even dozens of times larger than the power supply electromotive force, which often causes catastrophic damage to the external circuit. The hazards of induced electromotive force need to be avoided in actual use.

[0006] For example, the permanent magnetic release and its control circuit disclosed in the announcement number CN113903636A, by setting two coils in the coil assembly, the two coils control the guide rod to release and reset respectively, so that no other mechanical reset structure is required. However, the two coils need to be controlled by a control circuit respectively, and the residual induced electromotive force due to the influence of the magnetic field after the coil is powered off cannot be eliminated, and the magnetic fields between the two coils will affect each other for a certain period of time. Summary of the invention

[0007] In order to solve the above technical problems, the present invention provides a high-speed electromagnet with a fast demagnetization electromagnetic coil.

[0008] The present invention is achieved through the following technical solutions.

[0009] The invention provides a high-speed electromagnet with a fast demagnetization electromagnetic coil, comprising a yoke, in which a coil assembly is installed; the bottom of the yoke is closed by an end cover, an iron core is installed on the top of the yoke, the lower end of the iron core extends into the upper end of the coil assembly, an armature is movably installed at the lower end of the coil assembly, a push rod is fixedly provided at the center of the armature, and the upper end of the push rod extends into the central through hole of the iron core;

[0010] The coil assembly comprises a main coil and a degaussing coil. The magnetic fluxes generated by the main coil and the degaussing coil are of the same magnitude but opposite directions. A circuit on-off device is arranged on the power supply circuit of the degaussing coil.

[0011] The coil assembly also includes a coil bracket, which is fixed on the inner wall of the yoke. The main coil and the demagnetization coil are respectively and sequentially wound between the coil bracket and the yoke.

[0012] A guide tube is fixedly mounted on the inner wall of the coil support.

[0013] The iron core and the armature are both processed with cylindrical grooves at the centers facing opposite sides, and a compression spring is arranged in the cylindrical groove and installed on the push rod.

[0014] The main coil and the degaussing coil are connected in parallel in the power supply circuit, and a circuit switching device is arranged on the branch circuit connected to the degaussing coil.

[0015] The circuit on-off device blocks current from passing through the degaussing coil when the power supply line is connected; it conducts when the power supply line is disconnected, so that the main coil and the degaussing coil form a closed loop, and the current in the main coil flows into the degaussing coil to quickly degauss the main coil.

[0016] The beneficial effects of the present invention are as follows: when the main coil is powered off, the main coil and the degaussing coil form a closed loop, and the residual current of the main coil flows into the degaussing coil through the loop, which not only accelerates the speed at which the current on the main coil disappears, but also the residual magnetic flux of the main coil can be offset by the magnetic flux generated by the degaussing coil, so that the residual magnetic field energy around the armature is quickly consumed and the electromagnetic attraction is quickly reduced, thereby achieving the purpose of rapid response requirements of the electromagnet; at the same time, the induced electromotive force generated in the electromagnetic coil when the power is off is beneficially utilized, eliminating the impact of the induced electromotive force on the external circuit, thereby simplifying the external circuit and control requirements of the electromagnet, and expanding the application field of high-speed electromagnets. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of the present invention;

[0018] Figure 2 It is a schematic diagram of the coil structure of the present invention;

[0019] Figure 3 This is a schematic diagram of the circuit principle when two coils of the present invention are wound in the same direction;

[0020] Figure 4 It is a schematic diagram of the circuit principle when the two coils of the present invention are wound in opposite directions;

[0021] Figure 5 It is a schematic diagram of the principle of using a switch as a circuit on-off device of the present invention;

[0022] Figure 6 It is a schematic diagram of the connection structure of the double coil and the circuit on-off device of the present invention.

[0023] In the figure: 1- iron core, 2- yoke iron, 3- coil assembly, 31- coil bracket, 32- main coil, 33- degaussing coil, 34- positive pole of electromagnetic coil lead wire, 35- negative pole of electromagnetic coil lead wire, 4- guide tube, 5- armature, 51- push rod, 6- compression spring, 7- end cover, 8- circuit on-off device. DETAILED DESCRIPTION

[0024] The technical solution of the present invention is further described below, but the scope of protection claimed is not limited to the description.

[0025] A high-speed electromagnet with a fast demagnetization electromagnetic coil comprises a yoke 2, in which a coil assembly 3 is installed; the bottom of the yoke 2 is closed by an end cover 7, an iron core 1 is installed on the top of the yoke 2, the lower end of the iron core 1 extends into the upper end of the coil assembly 3, an armature 5 is movably installed at the lower end of the coil assembly 3, a push rod 51 is fixedly provided at the center of the armature 5, and the upper end of the push rod 51 extends into the central through hole of the iron core 1;

[0026] like Figure 2As shown, the coil assembly 3 includes a main coil 32 and a degaussing coil 33. The magnetic fluxes generated by the main coil 32 and the degaussing coil 33 are of the same magnitude but in opposite directions. A circuit switching device is provided on the power supply circuit of the degaussing coil 33. When the power is turned on and started, the circuit on-off device controls the starting current so that it cannot enter the degaussing coil through the diode, and the current flows normally into the main coil; at the moment when the electromagnet is powered off, the circuit on-off device is turned on, and because the electromagnetic coil stores electrical energy and its current cannot change instantaneously, the current of the main coil flows into the degaussing coil to form a closed loop; in the closed loop formed by the main coil, the degaussing coil and the circuit on-off device, the current is equal everywhere; according to Ampere's right-hand screw law, the current in the main coil and the degaussing coil has opposite spatial directions, and the magnetic flux they generate is just opposite; when the number of turns of the main coil and the degaussing coil is equal, the magnetic flux generated by the main coil and the degaussing coil just cancels each other, and the electrical energy stored in the main coil when the power is turned off and the induced electromotive force generated in the coil when the magnetic field changes are converted into heat energy consumption by the resistance of the coil itself, thereby achieving rapid attenuation of the electromagnetic attraction, and ultimately achieving the purpose of rapid response of the high-speed electromagnet. At the moment of power failure, an induced electromotive force several times that of the power supply will be generated in the main coil. Since the main coil and the degaussing coil form a closed loop, according to Kirchhoff's second law, the electromotive force at both ends of the main coil is equal to the electromotive force at both ends of the degaussing coil and the circuit switching device, thus avoiding the impact of the induced electromotive force in the electromagnet on the external circuit when the power is off.

[0027] The coil assembly 3 further includes a coil support 31, which is fixed on the inner wall of the yoke 2, and the main coil 32 and the demagnetization coil 33 are respectively wound between the coil support 31 and the yoke 2 in sequence.

[0028] There are no restrictions on the winding order and stacking position of the main coil and the degaussing coil. The key point is: when the power is off, the main coil and the degaussing coil will form a closed loop, and the magnetic field generated by the current in the main coil and the degaussing coil is in opposite directions. Through the application of this method, when the electromagnet is powered off, the main coil stores electrical energy, and the electromagnet stores magnetic field energy. The change in the magnetic field generates an induced electromotive force, and electricity and magnetism affect each other. The coil resistance quickly converts this energy into heat energy.

[0029] like Figure 1 As shown, this is a winding method for the main coil and demagnetization coil of the present application, the iron core 1 is installed on the yoke 2, the coil assembly 3 is installed inside the yoke 2, the guide tube 4 passes through the internal space of the coil assembly 3 and is connected to the iron core 1, the armature part 5 is installed inside the guide tube 4, and the compression spring 6 is installed between the iron core 1 and the armature part 5; the end cover 7 is fixed to the yoke 2 with fixing screws.

[0030] A guide tube 4 is fixedly mounted on the inner wall of the coil support 31 .

[0031] The core 1 and the armature 5 are both processed with cylindrical grooves at the centers facing each other, and a compression spring 6 is installed on the push rod 51 in the cylindrical groove.

[0032] The main coil 32 and the degaussing coil 33 are connected in parallel in the power supply circuit, and a circuit switching device is provided on the branch circuit connected to the degaussing coil 33.

[0033] The circuit on-off device blocks the current from passing through the degaussing coil 33 when the power supply line is connected; it is turned on when the power supply line is disconnected, so that the main coil 32 and the degaussing coil 33 form a closed loop, and the current in the main coil 32 flows into the degaussing coil 33 to quickly degauss the main coil 32.

[0034] Circuit switching devices are components that can switch the circuit on and off, such as diodes, MOS transistors, IGBTs, relays, etc. When the coils are wound, the two coils can be wound in the same direction, and the degaussing coil is connected to the main coil at the beginning and the end through a diode; the two coils can also be wound in opposite directions, and the end of the degaussing coil is connected to the main coil at the beginning through a diode. The double coil method provided by the present invention has no restrictions on the winding order and stacking position of the main coil and the degaussing coil. The key point is: when the power is off, the main coil and the degaussing coil will form a closed loop, and the magnetic field generated by the current in the main coil and the degaussing coil is in opposite directions. Through the application of this method, when the electromagnet is powered off, the main coil stores electrical energy, and the electromagnet stores magnetic field energy. The change in the magnetic field generates an induced electromotive force. Electricity and magnetism affect each other, and the coil resistance quickly converts this energy into heat energy. At the same time, the method provided by the present invention introduces the induced current generated in the main coil into the demagnetization coil to reduce the electromagnetic attraction of the electromagnet, thereby improving the response speed of the electromagnet. The beneficial effect of the present invention is that the induced electromotive force that is harmful to the circuit is effectively utilized, thereby avoiding the impact of the induced electromotive force on the external circuit.

[0035] Example: Figure 1 and 2 As shown, a degaussing coil is added to the electromagnet coil assembly, and the degaussing coil is connected to the positive pole of the diode and connected in parallel with the main coil; when the coil is energized, due to the unidirectional conduction of the diode, no current passes through the degaussing coil, and the main coil generates a magnetic flux to attract the electromagnet; when the electromagnet coil is de-energized, since the current in the main coil will not change instantly, the current will pass through the degaussing coil and turn on the diode, so that the main coil, the degaussing coil, and the diode form a closed loop; the winding direction of the main coil and the degaussing coil must make the magnetic flux directions of the main coil and the degaussing coil opposite, as shown in the attached figure Figure 3 As shown, the two coils are wound in the same direction, and the degaussing coil is connected to the main coil at the beginning and the end through the diode.

Claims

1. A high-speed electromagnet with a fast demagnetization electromagnetic coil, comprising a yoke (2), a coil assembly (3) being installed in the yoke (2), characterized in that: The bottom of the yoke (2) is closed by an end cover (7), an iron core (1) is installed on the top of the yoke (2), the lower end of the iron core (1) extends into the upper end of the coil assembly (3), an armature (5) is movably installed at the lower end of the coil assembly (3), a push rod (51) is fixedly provided at the center of the armature (5), and the upper end of the push rod (51) extends into the central through hole of the iron core (1); The coil assembly (3) comprises a main coil (32) and a degaussing coil (33); the magnetic fluxes generated by the main coil (32) and the degaussing coil (33) are of the same magnitude but opposite directions; and a circuit switching device is provided on the power supply line of the degaussing coil (33).

2. The high-speed electromagnet with a fast demagnetization electromagnetic coil according to claim 1, characterized in that: The coil assembly (3) also includes a coil support (31), the coil support (31) is fixed on the inner wall of the yoke (2), and the main coil (32) and the demagnetization coil (33) are respectively and sequentially wound between the coil support (31) and the yoke (2).

3. The high-speed electromagnet with a fast demagnetization electromagnetic coil as claimed in claim 2, characterized in that: A guide tube (4) is fixedly mounted on the inner wall of the coil support (31).

4. The high-speed electromagnet with a fast demagnetization electromagnetic coil as claimed in claim 1, characterized in that: The iron core (1) and the armature (5) are both machined with cylindrical grooves at the centers facing each other, and a compression spring (6) is installed on the push rod (51) in the cylindrical groove.

5. The high-speed electromagnet with a fast demagnetization electromagnetic coil as claimed in claim 1, characterized in that: The main coil (32) and the degaussing coil (33) are connected in parallel in a power supply circuit, and a circuit switching device is provided on a branch circuit connected to the degaussing coil (33).

6. The high-speed electromagnet with a fast demagnetization electromagnetic coil as claimed in claim 1, characterized in that: The circuit on-off device blocks current from passing through the degaussing coil (33) when the power supply line is connected; and is turned on when the power supply line is disconnected, so that the main coil (32) and the degaussing coil (33) form a closed loop, and the current in the main coil (32) flows into the degaussing coil (33) to quickly degauss the main coil (32).

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