A small brushless and commutatorless motor with automatic current regulation

Abstract

A small brushless and commutatorless motor with automatic current regulation, which is composed of a rotor, a rotor bracket, a battery box, a magnet and a switch. The rotor is wound into a multi-turn circular ring by enameled wire. The two ends of the enameled wire are stripped of the enameled wire insulation completely to serve as the rotor shaft. One end of the insulated wire is stripped of the insulation and wound into a solenoid to serve as the shaft support tube. The insulated wire is vertically fixed on the battery box to serve as the rotor bracket. The other end of the insulated wire is connected to both ends of the battery through a switch. The magnet is fixed on the battery box. The extension line of the rotor shaft does not coincide with the center of gravity of the rotor. The rotor shafts at both ends of the rotor are on the same straight line. After the shaft support tubes are placed on the rotor shafts at both ends of the rotor, the natural state of the rotor is that the coil plane of the rotor is in the vertical plane. The N pole or S pole of the magnet is close to the coil of the rotor, realizing the technology and method for demonstrating a small brushless and commutatorless motor with automatic current regulation.

Description

Technical Field

[0001] This patent relates to a small brushless and commutatorless motor with automatic current regulation, belonging to the field of physical demonstration experiment instruments. Background Art

[0002] Both brushed DC micro-motors and brushless motors are widely used. Brushed and brushless DC micro-motors are used in products such as model airplanes, toys, personal care, and security. The basic difference between a brushed micro DC motor and a brushless motor is that one has a brush and the other does not. In science and technology works or physics teaching, the first introduced is the brushed DC micro-motor. The brushed micro DC motor uses mechanical commutation. Its principle is that the magnetic poles do not move and the coil rotates. When the micro-motor operates, the coil and the commutator rotate, while the magnetic steel and the brush do not rotate. The direction of the current in the coil is completed by the commutator and the brush that rotate with the rotation of the micro-motor through alternating changes. So far, in physics teaching or scientific and technological creation, most people simply make this model with enameled wire to make the physical principle demonstration intuitive and clear. And teachers tell students that the rotor shaft led out from the circular coil wound with enameled wire in the rotor should strip the paint (insulating paint) on half of the side of the enameled wire (cylindrical), otherwise the produced demonstration motor cannot rotate. This conclusion has become a limitation restricting students' creativity. Therefore, the question is whether continuous directional rotation can be achieved when the side of the rotor shaft is completely stripped? Based on the above, those skilled in the art often give the answer of "it cannot rotate"; for this reason, the solution proposed in this patent is that the rotor can achieve continuous directional rotation. Currently, there is no visual and credible demonstration experiment for this problem. How to achieve a demonstration experiment instrument and method with rich demonstration content, obvious visual effects, and credibility is what this patent needs to solve. This patent is completed with the support of the National Natural Science Foundation of China (Project Nos.: 11805107, 11405092), the basic research funds for provincial universities in Heilongjiang Province (Project No.: 135209251), the teaching reform and application project of universities in Heilongjiang Province (Project No.: SJGY20170385), and the scientific and technological project of Qiqihar City (Project No.: GYGG-201423). Summary of the Invention

[0003] This patent solves the problem of a small brushless and commutatorless motor with automatic current regulation for use in class or after class. Specifically, through the full exposure of the rotor shaft (removing the insulation of the enameled wire on the shaft) and the positional relationship between the center of mass (center of gravity) of the rotor and the extension line of the rotor shaft, the inertial centrifugal force generated after the rotor rotates changes the pressure of the rotor shaft on the shaft support tube, realizing a technology and method for demonstrating a small brushless and commutatorless motor with automatic current regulation.

[0004] Technical solution of this patent: A brushless and commutatorless small motor with automatic current adjustment, mainly composed of a rotor, a rotor bracket, a battery box, a magnet and a switch. Its characteristics are as follows: The rotor is wound into a multi-turn circular ring by enameled wire (a copper material wire covered with a layer of insulating paint). Both ends of the enameled wire are stripped of the enameled wire insulation layer to serve as the rotor shaft, and both ends of the enameled wire are also the current inflow and outflow ends of the rotor. One end of the insulated sheath wire is stripped of the insulation sheath and wound into a solenoid as the shaft support tube. The insulated sheath wire is vertically fixed on the battery box (insulating material) as the rotor bracket. The other end of the insulated sheath wire is connected to the positive and negative poles of the battery through a switch. The magnet is fixed on the battery box. The extension line of the shaft of the rotor (rotor shaft) does not coincide with the center of gravity of the rotor. The rotor shafts at both ends of the rotor are on the same straight line. When the shaft support tubes are placed on the rotor shafts at both ends of the rotor, the natural state of the rotor is that the plane of the rotor coil is in the vertical plane. The N pole or S pole of the magnet is close to the coil of the rotor. The inner diameter of the shaft support tube satisfies that during the rotation of the rotor, when the center of gravity of the rotor is directly above the extension line of the rotor shaft, the rotor shaft can be non-contact (suspended) with the shaft support tube, or the rotor shaft can be in contact with the shaft support tube.

[0005] Brief analysis: In teaching, usually for an intuitive demonstration of the motor drive principle, the rotor is composed of one or several turns (number of turns N, area of each turn of the coil S) of enameled wire wound. Its mass is light, the contact area of the power supply wire is small, the current I is small, and the magnetic torque M is small. For the convenience of discussion, it is simplified that the rotor is in a uniform magnetic field B, and the maximum magnetic torque obtained in the uniform magnetic field B is M = ISNB.

[0006] Since in previous literature, half of the side of the rotor shaft is stripped, that is, in one cycle of rotor rotation, only half of the cycle (the normal of the rotor coil plane parallel to the magnetic force line is the boundary of half of the cycle) the Ampere torque does positive work, and in the other half of the cycle, the Ampere torque (current is zero) does not do work. In this way, the rotor can continuously rotate in a fixed direction; if the entire side of the rotor shaft is stripped, that is, in one cycle, only one half of the cycle the Ampere torque does positive work, and in the other half of the cycle, the Ampere torque does negative work (reverse torque), and the work done in one cycle is zero, that is, when doing the experiment, it can be seen that the plane of the rotor coil swings back and forth instead of rotating in a fixed direction.

[0007] Can continuous directional rotation be achieved when the entire side of the rotor shaft is stripped? Based on the above discussion, the answer of those skilled in the art is often that continuous directional rotation cannot be achieved; the answer of this patent is that it can be achieved. How does this patent achieve it? Since the rotor we designed is an eccentric rotor, centrifugal force is generated during the rotation of the rotor (coil). As shown in the appendix Figure 1There are: starting from the initial state (the coil plane of the rotor is in the vertical plane, and the center of gravity of the rotor is below the extension line of the shaft), the Ampere torque does positive work W1 during the process of rotating until the coil plane of the rotor is horizontal (the normal direction of the coil plane of the rotor is parallel to the magnetic field lines as the dividing line of half a period), and the pressure of the rotor shaft (when rotating) on the shaft support tube is greater than the gravity of the rotor; then starting from the horizontal state of the coil plane (the normal direction of the coil plane of the rotor is parallel to the magnetic field lines as the dividing line of half a period) until the coil plane of the next rotor is horizontal. In the process when the surface is horizontal (the normal of the coil plane of the rotor is parallel to the magnetic field line, which is the dividing line of half a cycle), the pressure of the rotor shaft on the shaft support tube is zero (out of contact) or less than the gravity of the rotor (the center of gravity of the rotor is above the extension line of the shaft), there is no Ampere torque work or the Ampere torque does negative work of W2, W2 plus the work done to overcome the rotor gravity is W3, W2+W3<W1; the net work after the Ampere torque work overcomes the friction torque work in one cycle is greater than zero, so that the rotor can rotate continuously in a certain direction.

[0008] Furthermore, for the convenience of discussion, Figure 1 , consider the process from the rotor mass center below the extension line of the shaft (initial) to the rotor mass center and the shaft in the same horizontal plane (horizontal) with current passing through the rotor, when the rotor mass center is above the extension line of the shaft, no current passes through the rotor, ignore the friction torque work, ignore the self-induced electromotive force, ignore the internal resistance of the battery, take the current I as the maximum current (just started), there is magnetic torque work to overcome the gravity work (the rotor mass center moves in a circle, so that the mass center reaches the highest point) to obtain a speed of v

[0009]

[0010]

[0011] Assuming the rotor support force F is zero, combining the above equations, we have

[0012] NISB>5rmg / 2

[0013] For the convenience of discussion, let s1 be the cross-sectional area of the rotor conductor and the resistance of the rotor coil be R.

[0014]

[0015]

[0016]

[0017] Substituting the above three expressions of R, I, and m into NISB>5rmg / 2, we get:

[0018] To keep the rotor rotating continuously, Relationship, that is, satisfaction When considering this relationship, the rotor cannot rotate continuously; (If we consider the center of mass of the rotor is below the extension line of the rotating shaft, starting from the situation where the center of mass of the rotor and the rotating shaft are in the same horizontal plane, passing through the center of mass of the rotor being below the extension line of the rotating shaft and then back to the situation where the center of mass (center of gravity) of the rotor and the rotating shaft are in the same horizontal plane, the work done is twice that of the process from the center of mass of the rotor being below the extension line of the rotating shaft to the center of mass of the rotor and the rotating shaft being in the same horizontal plane. That is, if it satisfies it is even more impossible to achieve continuous rotation of the rotor);

[0019] Where, N is the number of turns of the rotor coil, I is the current intensity in the coil, S is the area of a single-turn coil, B is the magnetic field intensity of the magnet in the coil, r is the radius of the distance between the center of mass of the rotor and the rotating shaft, m is the mass of the rotor, g is the acceleration due to gravity, ε is the potential difference across the rotor, R is the total resistance of the rotor, s1 is the cross-sectional area of the rotor wire, d is the wire diameter, ρ is the wire resistivity, ρ1 is the bulk density of the wire, and a is the radius of a single-turn coil.

[0020] This problem arose as follows: In 1996, the inventor wanted to make a demonstration motor (driven by Ampere force) with a rotor coil diameter of 5 mm. According to the principles in textbooks, it couldn't be achieved. It was found that when the rotor had one turn, it was light in mass and had a small contact area with the shaft support ring (connected to the electrode). Although the rotor shaft was also designed according to textbooks, directional rotation couldn't be achieved. So the number of turns of the rotor coil was increased to 5 turns, and the shaft support ring was changed to a shaft support tube (solenoid shape), which enabled the rotor to rotate directionally. However, for a relatively thin enameled wire, such as an enameled wire with a diameter of 0.41 mm and a rotor made with a coil diameter of 5 mm, when processed according to the production process in textbooks, it was very difficult to strip away half of the thin enameled wire on the side when dealing with the rotor shaft, increasing the processing difficulty. During processing, either half of it wasn't stripped away or it was all stripped off. After many tests and adjustments, it was found that sometimes the rotor rotated continuously easily and sometimes only showed a swinging phenomenon when the rotor shaft was completely bare. After careful observation of the internal driving mechanism and finally through theoretical analysis combined with practice to reach an agreement, the preliminary scheme of this patent was obtained. The demonstration success rate of this patent designed and made according to this rule was 100%. In subsequent teaching experiments, we also tried using enameled iron wire (iron wire soaked in insulating paint on the outside) as the coil of the rotor of the motor. What occurred was that the rotor coil swung and couldn't move directionally and continuously. Iron wire belongs to ferromagnetic material and is attracted by the magnetic force of the magnet more strongly. For the Ampere force generated by the rotor coil driven by an ordinary 3-volt dry battery, it is less than the magnetic force of the magnet on the coil. Therefore, when the force arms are the same, the magnetic moment generated by the magnet is greater than the Ampere force moment. That is to say, within the range near the vertical plane where the rotor coil is located, the moment of the magnet attracting the rotor coil (iron wire) can be less than the Ampere force moment generated by the current in the rotor coil in the magnetic field. As the angle between the rotor coil and the vertical plane increases, the moment of the magnet attracting the rotor coil (iron wire) also increases. Therefore, to drive the rotor to rotate continuously with the Ampere moment generated by the current in the rotor coil, a large current is necessary. The combination of theory and practice is conducive to cultivating students' creativity.

[0021] The outstanding substantive features and remarkable progress compared with the prior art are as follows: 1. The structural feature of this design is that the center of mass of the rotor is not on the same straight line as the rotor shaft. The inertial centrifugal force generated after the rotor rotates changes the pressure of the rotor shaft on the shaft support tube (the pressure can be greater than the magnitude of the rotor's own gravity (when the center of mass of the rotor is below the connecting line of the shafts), zero (when the center of mass of the rotor is above the connecting line of the shafts), or significantly less than the magnitude of its own gravity (when the center of mass of the rotor is above the connecting line of the shafts)). In this way, within one rotation period, the pressure of the rotor shaft on the shaft support tube changes periodically, changing the contact area between the rotor shaft and the shaft support tube, and the magnitude of the current also changes periodically, realizing the self-adjustment of the rotor's own current after the rotor rotates, so as to achieve the continuous directional rotation of the completely bare rotor shaft; 2. All the insulating paint is removed from the enameled wire of the rotor shaft. Especially for thin enameled wires and small-scale rotors (such as those with a coil diameter less than 5 mm and an enameled wire diameter less than 0.41 mm), it is easier to achieve in processing than the prior art (where half of the side of the enameled wire on the rotor shaft in textbooks has the insulating paint removed), the structure is simpler, the demonstration effect is obvious, and it is easy to achieve continuous rotation. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Appendix Figure 1 is a schematic diagram of the principle of this patent

[0023] Appendix Figure 2 is a schematic diagram of the structure of this patent

[0024] Wherein: 1. Rotor (wound with enameled wire made of copper material), 1-1. Rotor shaft (copper wire without enamel coating), 2. Rotor bracket, 2-1. Shaft support tube, 3. Battery box, 4. Magnet (permanent magnet). DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] As shown in the appendix Figure 2: A small brushless and commutatorless motor with automatic current regulation, mainly composed of a rotor 1, a rotor bracket 2, a battery box 3, a magnet 4 and a switch. Its characteristics are as follows: The rotor 1 is wound into a multi-turn circular ring by enameled wire. The two ends of the enameled wire are stripped of the enameled wire insulation completely to serve as the rotor shaft 1-1, and the two ends of the enameled wire are also the current inlet and outlet ends in the rotor 1; One end of the insulated sheathed wire is stripped of the insulation and wound into a solenoid to serve as the shaft support tube 2-1. The insulated sheathed wire is vertically fixed on the battery box 3 (insulating material) to serve as the rotor bracket 2. The other end of the insulated sheathed wire is connected to the positive and negative poles of the battery through a switch; The magnet 4 is fixed on the battery box 3. The extension line of the shaft of the rotor 1 (rotor shaft 1-1) does not coincide with the center of gravity of the rotor 1. The rotor shafts 1-1 at both ends of the rotor 1 are on the same straight line. After the rotor shafts 1-1 at both ends of the rotor 1 are placed in the shaft support tube 2-1, the natural state of the rotor 1 is that the coil plane of the rotor 1 is in the vertical plane. The N pole or S pole of the magnet 4 is close to the coil of the rotor 1. The inner diameter of the shaft support tube 2-1 satisfies that during the rotation of the rotor 1, when the center of gravity (center of mass) of the rotor 1 is directly above the extension line of the rotor shaft 1-1, the rotor shaft 1-1 can be non-contact (suspended) with the shaft support tube 2-1, or the rotor shaft 1-1 can be in contact with the shaft support tube 2-1.

Claims

1. A brushless and commutatorless small motor with automatic current regulation, which consists of a rotor (1), a rotor bracket (2), a battery box (3), a magnet (4) and a switch, and is characterized in that: The rotor (1) is wound into a multi-turn circular ring by enameled wire. The two ends of the enameled wire are completely stripped of the enameled wire sheath to serve as the rotor shaft (1-1). The two ends of the enameled wire are also the current inflow and outflow ends in the rotor (1). One end of the insulated sheath wire is stripped of the insulation sheath and wound into a solenoid to serve as the shaft support tube (2-1). The insulated sheath wire is vertically fixed on the battery box (3) to serve as the rotor support (2). The other end of the insulated sheath wire is connected to the positive and negative poles of the battery through a switch. The magnet (4) is fixed on the battery box (3). The extension line of the shaft of the rotor (1) does not coincide with the centroid of the rotor (1). The rotor shafts (1-1) at both ends of the rotor (1) are on the same straight line. After the rotor shafts (1-1) at both ends of the rotor (1) are placed in the shaft support tube (2-1), the natural state of the rotor (1) is that the coil plane of the rotor (1) is in the vertical plane. The N pole or S pole of the magnet (4) is close to the coil of the rotor (1), and the shaft support tube (2-1) also prevents the rotor (1) from falling off. The diameter of the enameled wire of the rotor (1) is less than 0.41 mm, the diameter of the rotor (1) coil is less than 5 mm, and the number of turns of the coil is 5. The centroid of the rotor (1) and the rotor shaft (1-1) are not on the same straight line. The inertial centrifugal force generated by the rotation of the rotor (1) changes the pressure of the rotor shaft (1-1) on the shaft support tube (2-1). When the centroid of the rotor (1) is below the connection line of the shafts, the above pressure is greater than the self-gravity of the rotor (1). When the centroid of the rotor (1) is above the connection line of the shafts, the above pressure is zero. In this way, within one rotation period, the pressure of the rotor shaft (1-1) on the shaft support tube (2-1) changes periodically, changing the contact area between the rotor shaft (1-1) and the shaft support tube (2-1), and the current magnitude also changes periodically, realizing the self-adjustment of the current of the rotor (1) itself after the rotor (1) rotates, so as to achieve the continuous directional rotation of the completely naked rotor shaft (1-1).

Images