Brushless motor without attracting iron powder

Abstract

The invention discloses a brushless motor without attracting iron powder, which comprises a motor stator main body, a motor rotor main body is rotatably connected in the motor stator main body, the motor stator main body comprises stator punching sheets, a connection gap is arranged between the motor stator main body and the motor rotor main body, the motor rotor main body comprises rotor punching sheets, and the rotor punching sheets are arranged in the connection gap. A rotor punching sheet is arranged on the motor stator main body, a magnetic steel sheet is arranged on the rotor punching sheet, an enameled wire is arranged at a stator winding position on the inner side of the motor stator main body, the maximum gap between the motor stator main body and the motor rotor main body is 1.45 mm, and the minimum gap between the motor stator main body and the motor rotor main body is 0.4 mm. According to the brushless motor without attracting iron powder, the stator and rotor structures of the motor are changed, the magnetic field distribution is changed, the motion state of iron dust particles is changed, the iron dust particles cannot be attracted by strong magnets on the rotor, the iron dust particles move smoothly and are not blocked in air gaps of the stator and the rotor, and the motor works normally.

Description

Technical Field

[0001] The invention relates to the technical field of brushless motors, and in particular to a brushless motor that does not absorb iron powder. Background Art

[0002] Brushless motors are energy-driven supporting equipment that are widely used in various tools and application scenarios, among which marine shipbuilding is indispensable. Traditional series-excited motors are unable to meet the needs of high-strength marine ship scenarios due to insufficient power and torque, high energy consumption, and low efficiency. Brushless motors have high power, high torque, high efficiency, long life, and a wide range of applicable scenarios. This type of motor is used in high-voltage brushless angle grinders and can be used in the manufacture of marine ship equipment. It has high power and strong torque, and is suitable for the needs of high-strength structures of marine equipment that need to be polished and cut. However, during the grinding process of shipbuilding, a large amount of iron dust will be generated, and the strong magnetic motor rotor will strongly absorb iron powder, which will accumulate and block the stator-rotor air gap, causing heat and demagnetization, the motor will be weak, and the tool cannot be used. In order to solve the problem that the motor rotor of conventional brushless motors strongly absorbs iron powder in the use scenario, we redesigned a brushless motor whose motor structure does not absorb iron powder. Summary of the invention

[0003] Technical problem to be solved: In view of the shortcomings of the prior art, the present invention provides a brushless motor that does not attract iron powder, changes the stator and rotor structure of the motor, changes the magnetic field distribution, and changes the movement state of iron dust particles. The strong magnet on the rotor cannot attract iron dust particles, and the iron dust particles can move smoothly in the air gap between the stator and rotor without blockage. The motor works normally, which can effectively solve the problems in the background technology.

[0004] Technical solution: To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a brushless motor that does not absorb iron powder, comprising a motor stator body, the internal rotation of the motor stator body is connected to a motor rotor body, the motor stator body comprises a stator punching, a connection gap is set between the motor stator body and the motor rotor body, the motor rotor body comprises a rotor punching, a magnetic steel sheet is set on the rotor punching, an enameled wire is set at the stator winding position on the inner side of the motor stator body, the maximum gap between the motor stator body and the motor rotor body is 1.45mm, and the minimum gap between the motor stator body and the motor rotor body is 0.4mm.

[0005] As a preferred technical solution of the present application, in the structure composed of the motor stator body and the motor rotor body, the force direction of the iron powder particles in the magnetic field is opposite to the movement direction of the rotor punching.

[0006] As a preferred technical solution of the present application, during the rotation of the fan blades, the direction of the wind entering between the motor stator body and the motor rotor body is the same as the movement direction of the rotor punching.

[0007] As a preferred technical solution of the present application, the wind drives the iron powder particles to move axially in a spiral manner toward the air outlet between the air gap between the motor stator body and the motor rotor body, and the iron powder particles obtain kinetic energy, momentum and driving force under the pressure of the wind.

[0008] As a preferred technical solution of the present application, the iron powder particles are subjected to the thrust of wind pressure during the movement between the air gap between the motor stator body and the motor rotor body, which offsets a portion of the force exerted on the iron particles in the magnetic field. At this time, the ferromagnetic attraction of the iron powder particles is weakened, and the iron powder particles are weakened from being adsorbed by the ferromagnetic surface. The iron powder particles flow axially spirally toward the air outlet along the wind and are discharged from the machine body without sticking to the inner cavity of the motor.

[0009] As a preferred technical solution of the present application, the iron powder particles are subjected to a force in a magnetic field: F1=m.▽B; wherein F1 is the force on the iron powder particles in the magnetic field, m is the magnetic moment vector of the iron powder particles in the magnetic field, "." is the dot product, ▽ is the divergence, and B is the magnetic field induction intensity;

[0010] F2=Pq*S

[0011] Pq=Pi+Pb,Pb=0.5*ρ*υ2

[0012] Among them, F2 is the force of air pushing iron powder particles forward, S is the surface area of ​​iron powder particles, Pq is the total pressure of gas, Pi is the forbidden pressure of gas, Pb is the pressure generated by air movement, ρ is the air density, and υ is the air flow velocity.

[0013] As a preferred technical solution of the present application, the motor stator body and the motor rotor body form a brushless motor to perform energy conversion, converting electrical energy into mechanical energy: Pe=TeΩ, where Pe is electromagnetic power, Te is electromagnetic torque, Ω=W1 / P, W1 is the stator current frequency, and P is the logarithm of the magnetic magnitude.

[0014] Beneficial effects: Compared with the prior art, the present invention provides a brushless motor that does not attract iron powder, which has the following beneficial effects: the brushless motor that does not attract iron powder changes the stator and rotor structure of the motor, changes the magnetic field distribution, and changes the movement state of iron dust particles. The strong magnet on the rotor cannot attract iron dust particles, and the iron dust particles can move smoothly in the air gap between the stator and rotor without blockage, and the motor works normally. The brushless motor with this structure is used in the shipbuilding and grinding process. In the environment of strong iron dust, the strong magnet of the motor does not attract iron powder, the motor generates very little heat, and the motor has the advantages of high power, high torque, high working efficiency, low energy consumption, and low cost. The entire brushless motor has a simple structure, is easy to operate, and has a better use effect than other brushless motor methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 The figure is a schematic diagram of the overall structure of a brushless motor that does not absorb iron powder according to the present invention.

[0016] Figure 2 The present invention is a schematic structural diagram of the connection between the stator punching sheet and the rotor punching sheet in a brushless motor that does not absorb iron powder.

[0017] Figure 3 The present invention is a schematic structural diagram of the overall side surface of a brushless motor that does not absorb iron powder.

[0018] Figure 4 This is the control schematic diagram of the brushless DC motor.

[0019] Figure 5 This is the control schematic diagram of the AC brushless motor.

[0020] Figure 6 This is the voltage phasor diagram of the brushless permanent magnet motor.

[0021] Figure 7 The figure is a force diagram of iron powder particles (iron powder with small magnetic moment) in a brushless motor that does not absorb iron powder according to the present invention.

[0022] In the figure: 1. motor stator body; 2. motor rotor body; 101. stator punching sheet; 102. connection gap; 103. enameled wire; 201. rotor punching sheet; 202. magnetic steel sheet. DETAILED DESCRIPTION

[0023] The technical scheme of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and specific embodiments, but it will be understood by those skilled in the art that the following described embodiments are part of embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention. If specific conditions are not specified in the embodiments, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not specified in the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0024] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0025] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0026] like Figure 1-7 As shown, a brushless motor that does not absorb iron powder includes a motor stator body 1, the motor stator body 1 is internally rotatably connected with a motor rotor body 2, the motor stator body 1 includes a stator punching sheet 101, a connection gap 102 is arranged between the motor stator body 1 and the motor rotor body 2, the motor rotor body 2 includes a rotor punching sheet 201, a magnetic steel sheet 202 is arranged on the rotor punching sheet 201, an enameled wire 103 is arranged at the stator winding position on the inner side of the motor stator body 1, the maximum gap between the motor stator body 1 and the motor rotor body 2 is 1.45mm, and the minimum gap between the motor stator body 1 and the motor rotor body 2 is 0.4mm. The motor stator and rotor structure is changed, the magnetic field distribution is changed, and the movement state of the iron dust particles is changed. The strong magnet on the rotor cannot absorb the iron dust particles, and the iron dust particles move smoothly in the stator and rotor air gap without blockage, and the motor works normally.

[0027] Furthermore, in the structure composed of the motor stator body 1 and the motor rotor body 2 , the force direction of the iron powder particles in the magnetic field is opposite to the movement direction of the rotor punching 201 .

[0028] Furthermore, during the rotation of the fan blades, the direction of the wind entering between the motor stator body 1 and the motor rotor body 2 is the same as the movement direction of the rotor punching 201 .

[0029] Furthermore, the wind drives the iron powder particles to move axially and spirally toward the air outlet between the air gap between the motor stator body 1 and the motor rotor body 2, and the iron powder particles obtain kinetic energy, momentum and driving force driven by the pressure of the wind.

[0030] Furthermore, the iron powder particles are subjected to the thrust of wind pressure during the movement between the air gap of the motor stator body 1 and the motor rotor body 2, which offsets a part of the force on the iron particles in the magnetic field. At this time, the ferromagnetic attraction of the iron powder particles is weakened, and the iron powder particles are weakened from being adsorbed by the ferromagnetic surface. The iron powder particles flow toward the air outlet in an axial spiral along the wind and are discharged from the body without sticking to the inner cavity of the motor.

[0031] Furthermore, the force on the iron powder particles in the magnetic field is: F1=m.▽B; where F1 is the force on the iron powder particles in the magnetic field, m is the magnetic moment vector of the iron powder particles in the magnetic field, "." is the dot product, ▽ is the divergence, and B is the magnetic field induction intensity;

[0032] F2=Pq*S

[0033] Pq=Pi+Pb,Pb=0.5*ρ*υ2

[0034] Among them, F2 is the force of air pushing iron powder particles forward, S is the surface area of ​​iron powder particles, Pq is the total pressure of gas, Pi is the forbidden pressure of gas, Pb is the pressure generated by air movement, ρ is the air density, and υ is the air flow velocity.

[0035] Furthermore, the motor stator body 1 and the motor rotor body 2 form a brushless motor to perform energy conversion, converting electrical energy into mechanical energy: Pe=TeΩ, where Pe is electromagnetic power, Te is electromagnetic torque, Ω=W1 / P, W1 is the stator current frequency, and P is the logarithm of the magnetic magnitude.

[0036] 1: The principle of brushless motor movement:

[0037] The energy conversion of brushless motor is also from electrical energy to mechanical energy: Pe = TeΩ (P E is electromagnetic power, Te is electromagnetic torque, Ω=W1 / P, W1 is stator current frequency, P is magnetic level logarithm)

[0038] The generation of electricity in AC and DC brushless motors: The control circuit turns on the inverter power tube according to the algorithm sequence to supply power to the motor stator coil. The generation of electromagnetic torque in AC and DC brushless motors: When electricity passes through the stator coil, the magnetic field of the rotor is cut by the stator coil, generating induced electromotive force. The conductor with current generates electromagnetic torque under the action of the magnetic field force. The rotor generates rotor motion under the action of the electromagnetic torque, realizing the conversion of electrical energy into magnetic energy and magnetic energy into mechanical energy.

[0039] Brushless motor voltage equation:

[0040]

[0041] E 0 The main magnetic flux Q0 generated by the permanent magnet generates the exciting electromotive force in the stator winding

[0042] Ra is the stator resistance per phase, and The stator current is

[0043] Straight

[0044] The direct-axis and quadrature-axis components, Xd and Xq are the reactance virtual electromotive force of the direct-axis and quadrature-axis:

[0045]

[0046] Electromagnetic power: Electromagnetic torque:

[0047]

[0048]

[0049]

[0050] 2. Pain points encountered in brushless motor movement

[0051] Pain points encountered in the movement of brushless motors: Brushless motors are prone to heat up in dusty (iron dust) environments. The movement principle of brushless motors has been explained earlier: the power of the power supply is turned on by the control circuit in an algorithmic sequence to turn on the inverter power tube and supply power to the stator coil of the motor. The conductor with current generates electromagnetic torque under the action of the magnetic field force, and the rotor generates rotor movement under the action of the electromagnetic torque. Advantages of brushless motors in scene applications: motors of the same weight, high power and strong torque, which meet the needs of high power and high torque in the scene. However, some products (such as angle grinders) will generate heat during use due to blockage or accumulation of iron powder, and may burn out in severe cases.

[0052] In order to solve the pain points of the product, the present invention: changes the structure of the stator and rotor, changes the distribution of the magnetic field in the air gap between the stator and rotor, thereby changing the movement state of the particles in the magnetic field, reducing the force applied to the particles during movement, making it difficult for the particles to be adsorbed by the rotor and carried away by the wind, and making it difficult for the stator and rotor of the machine to be blocked, and there is no heat or burning phenomenon.

[0053] 3: The state of iron powder particles in the magnetic field

[0054] The reason why iron powder particles are attracted by magnets is that the magnetic field generated by the magnet interacts with the electrons in the iron powder. Magnets are objects that can have a magnetic field, and they can adsorb ferromagnetic materials such as iron and cobalt. The principle of magnet adsorbing iron is based on the action of the magnetic field, which is generated by the movement of electrons in the magnet. These electron movements generate a magnetic field, which will act on the surrounding objects and adsorb ferromagnetic materials on the surface of the magnet. The electrons in the iron powder have spin and orbital angular momentum, and these angular momenta interact to form a magnetic moment. Since the spin and orbital angular momentum of the electrons in the iron powder are regular, the interaction between them forms a relatively large magnetic moment. When the magnetic field of the magnet acts on these magnetic moments, the electrons in the iron powder will be deflected, causing the iron powder to be attracted by the magnet. When more iron powder particles are adsorbed, the magnet heats up and the magnetic properties decrease. Iron powder particles will not be adsorbed in a uniform magnetic field. But in actual application scenarios, the magnetic field is uneven. Iron powder particles will be adsorbed on the surface of the magnet in an uneven magnetic field. In practical applications, the air gap between the stator and rotor of the motor is an uneven air gap. Due to the different distribution density of the air gap magnetic field, the iron particles are magnetized into small magnetic moments under the magnetic field. These small magnetic moments have different potential energies in the uneven magnetic field, causing the small magnetic moments to be acted upon by forces in the magnetic field. The direction of this force is from the part with small magnetic induction intensity to the part with large magnetic induction intensity, causing it to be attracted by the magnet.

[0055] 4. Change the force state of iron powder particles in the magnetic field

[0056] Change the structure of the motor's stator and rotor so that the force direction of the iron powder particles in the magnetic field is opposite to the movement direction of the rotor. When the fan blades rotate, the direction of the wind entering between the stator and rotor is the same as the movement direction of the rotor. The wind drives the iron powder particles to move in an axial spiral between the stator and rotor air gap toward the air outlet. Driven by the pressure of the wind, the iron powder particles gain kinetic energy, momentum and driving force. During the movement between the stator and rotor air gaps, the iron powder particles are subjected to the thrust of wind pressure, which offsets part of the force on the iron particles in the magnetic field. At this time, the ferromagnetic attraction of the iron powder particles is weakened, and the iron powder particles are weakened from being adsorbed by the ferromagnetic surface. The iron powder flows to the air outlet in an axial spiral with the wind and is discharged from the machine body without sticking to the inner cavity of the motor. The analysis is as follows:

[0057] The force exerted on the iron powder particles in the magnetic field is: F1=m.▽BF1 is the force exerted on the iron powder particles in the magnetic field, m is the magnetic moment vector of the iron powder particles in the magnetic field, “.” dot product, ▽ is the divergence, and B is the magnetic field induction intensity.

[0058] F2=Pq*SPq=Pi+Pb,Pb=0.5*ρ*υ2F2 is the force of air pushing iron powder particles forward, S is the surface area of ​​iron powder particles. Pq is the total pressure of gas, Pi is the pressure prohibited by gas, Pb is the pressure generated by air movement, ρ is the air density, υ is the air flow speed.

[0059] Working principle: It uses a synchronous (DC) brushless permanent magnet motor and works through an electronically controlled inverter. The brushless motor electronic control system can be used in a wide range of scenarios. This type of motor is used in high-voltage brushless angle grinders and can be used in the manufacture of marine ship equipment. It has high power and strong torque, and is suitable for the needs of grinding and cutting high-strength structures of marine equipment.

[0060] However, the high-voltage brushless angle grinder of this motor produces a large amount of iron dust during the grinding process in shipbuilding. The strong magnetic motor rotor will strongly absorb the iron powder, which will accumulate and block the air gap between the stator and rotor, causing heat and demagnetization, making the motor weak and the tool unusable.

[0061] Changing the stator and rotor structure of the motor changes the magnetic field distribution and the movement state of the iron dust particles. The strong magnet on the rotor cannot attract the iron dust particles. The iron dust particles can move smoothly in the air gap between the stator and rotor without blockage, and the motor works normally.

[0062] It should be noted that, in this article, relational terms such as first and second (number one, number two), etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "including one..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0063] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited by the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention to be protected.

Claims

1. A brushless motor that does not absorb iron powder, comprising a motor stator body (1), characterized in that: The motor stator body (1) is rotatably connected to a motor rotor body (2) inside, the motor stator body (1) comprises a stator punching sheet (101), a connection gap (102) is provided between the motor stator body (1) and the motor rotor body (2), the motor rotor body (2) comprises a rotor punching sheet (201), a magnetic steel sheet (202) is provided on the rotor punching sheet (201), an enameled wire (103) is provided at the stator winding position inside the motor stator body (1), the maximum gap between the motor stator body (1) and the motor rotor body (2) is 1.45 mm, and the minimum gap between the motor stator body (1) and the motor rotor body (2) is 0.4 mm.

2. A brushless motor without iron powder absorption according to claim 1, characterized in that: In the structure composed of the motor stator body (1) and the motor rotor body (2), the force direction of the iron powder particles in the magnetic field is opposite to the movement direction of the rotor punching sheet (201).

3. The brushless motor without iron powder absorption according to claim 1, characterized in that: During the rotation of the fan blades, the direction of the wind entering between the motor stator body (1) and the motor rotor body (2) is the same as the movement direction of the rotor punching (201).

4. The brushless motor without iron powder absorption according to claim 1, characterized in that: The wind drives the iron powder particles to move in an axial spiral manner toward the air outlet between the air gap between the motor stator body (1) and the motor rotor body (2), and the iron powder particles obtain kinetic energy, momentum and driving force under the pressure of the wind.

5. The brushless motor without iron powder absorption according to claim 4, characterized in that: The iron powder particles are subjected to the thrust of wind pressure during movement between the air gap of the motor stator body (1) and the motor rotor body (2), which offsets a portion of the force exerted on the iron particles in the magnetic field. At this time, the ferromagnetic attraction of the iron powder particles is weakened, and the iron powder particles are weakened from being adsorbed by the ferromagnetic surface. The iron powder particles flow axially and spirally toward the air outlet along with the wind and are discharged from the machine body without sticking to the inner cavity of the motor.

6. The brushless motor without iron powder absorption according to claim 5, characterized in that: The iron powder particles are subjected to a force in the magnetic field: F1=m.▽B; wherein F1 is the force on the iron powder particles in the magnetic field, m is the magnetic moment vector of the iron powder particles in the magnetic field, ". " is the dot product, ▽ is the divergence, and B is the magnetic field induction intensity; F2=Pq*S Pq=Pi+Pb,Pb=0.5*ρ*υ2 Among them, F2 is the force of air pushing iron powder particles forward, S is the surface area of ​​iron powder particles, Pq is the total pressure of gas, Pi is the forbidden pressure of gas, Pb is the pressure generated by air movement, ρ is the air density, and υ is the air flow velocity.

7. The brushless motor without iron powder absorption according to claim 1, characterized in that: The motor stator body (1) and the motor rotor body (2) form a brushless motor to perform energy conversion, converting electrical energy into mechanical energy: Pe=TeΩ, wherein Pe is electromagnetic power, Te is electromagnetic torque, Ω=W1 / P, W1 is the stator current frequency, and P is the logarithm of the magnetic level.

Images