Electric motor

Abstract

To provide an inner rotor type or outer rotor type motor capable of variably controlling a gap between magnetic poles of a permanent magnet of a rotor and an electromagnet of a stator to a gap for achieving high-speed cruising performance and energy saving while securing acceleration performance.SOLUTION: An electric motor comprising: a rotor having a shaft center connected to a rotary drive shaft and having permanent magnets arranged in a circumferential direction; and a stator arranged in the circumferential direction on an inner periphery or an outer side of the rotor with an electromagnetic pole of an electromagnet facing a magnetic pole surface of the permanent magnet with a predetermined gap therebetween, the electromagnetic pole includes an electromagnetic cylinder having a coil wound around an outer peripheral surface thereof, and an electromagnetic movable rod slidably provided in the electromagnetic cylinder, and the electromagnetic movable rod is connected to a forward and backward drive mechanism in which a gap between an electromagnetic pole end surface at a tip end thereof and a magnetic pole surface of the permanent magnet is varied to be close to or separated from each other according to a rotation speed of the rotor.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an inner rotor or outer rotor electric motor such as a motor or a dynamo (generator). [Background technology]

[0002] To optimize the torque and rotation speed of an electric vehicle, high torque is required when starting or climbing hills, and low torque and high rotation speed when cruising at high speeds, as shown in Figure 7. Various methods have been invented in the past to achieve this optimization, but the most effective method is the "variable magnetic field system," and various mechanisms have been announced by various companies and research institutes. Major electric vehicle manufacturers are also researching whether changing some of the components in the motor manufacturing process can achieve the desired optimization, i.e., improving driving range through energy savings, without making major modifications to other processes.

[0003] Although the motors installed in electric vehicles have superior acceleration performance compared to internal combustion engines, their high-speed cruising performance is a bottleneck, and their use as a practical means of transportation is limited to a certain extent. In other words, in terms of the relationship between "torque and rotation speed," the performance required of a motor is also in line with the "Drive characteristics diagram of motors required for automobiles and railways" in a paper by the Department of Electrical, Electronic and Information Engineering, Faculty of Science and Technology, Toyo University.

[0004] In other words, the driving characteristics required of a motor are appropriate torque and rotation speed according to the operating conditions, and the distribution of the energy required for each. The same motor is required to achieve both "high magnetic force - low speed" and "low magnetic force - high speed" while minimizing energy waste, and the same thing is being pointed out unanimously for gasoline vehicles as well. A common point is that high torque is not required for high-speed driving, and the motor rotation speed must be increased. Therefore, if energy conservation can be achieved like in gasoline vehicles, fuel efficiency will improve and the driving range will increase. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] : JP 2023-103146 ​​A [Patent Document 2] : JP 2023-103145 A DISCLOSURE OF THE INVENTION [Problem to be solved by the invention]

[0006] The inventors of the present invention have previously developed inner rotor or outer rotor electric motors in which the magnetic pole gap between the rotor and stator can be moved back and forth, as described in Patent Documents 1 and 2, thereby achieving high-speed range and energy savings while ensuring acceleration performance. These electric motors feature a reciprocating drive mechanism that adjusts the reciprocating movement of the magnetic pole gap between the rotor and stator, such as a mechanism that moves the rotor or stator itself back and forth in its radial direction. Problems with these reciprocating mechanisms include the difficulty of maintaining the wiring in the case of a stator due to the operation of an electromagnetic coil, and the difficulty of maintaining the rotational drive support mechanism in the case of a rotor due to the divided rotation of a permanent magnet. Furthermore, the reciprocating mechanism itself, which is common to both, is structurally complex, making maintenance difficult. The present invention provides an inner rotor or outer rotor electric motor that solves the above-mentioned problem by preventing the rotor or stator itself from moving back and forth in the radial direction, and by improving the structure of only the electromagnetic poles of the stator itself, makes it possible to variably control the gap between the magnetic poles to a gap that achieves high-speed cruising performance and energy savings while ensuring acceleration performance. [Means for solving the problem]

[0007] The main technical configurations of the electric motor of the present invention that satisfy the above-mentioned problems are as follows (1) and (2). (1) An electric motor comprising a rotor whose axis is connected to a rotary drive shaft and whose permanent magnets are arranged circumferentially, and a stator whose electromagnetic poles of electromagnets are arranged circumferentially on the inner or outer periphery of the rotor so as to face the magnetic pole faces of the permanent magnets with a predetermined gap, wherein the electromagnetic poles are composed of an electromagnetic cylinder whose outer periphery is wound with a coil, and an electromagnetic movable rod slidably arranged within the electromagnetic cylinder, and the electromagnetic pole end face of the electromagnetic movable rod is connected to a forward / backward drive mechanism which varies the facing surface gap between the tip of the electromagnetic pole end face and the magnetic pole face of the permanent magnet according to the rotation speed of the rotor. (2) The electric motor described in (1) above is characterized in that the advancing / retreating drive mechanism comprises a rotating disk that reversibly operates one of a small motor, a solenoid mechanism, or an air cylinder mechanism, depending on the rotational speed of the rotor and the electromagnetic density, to vary the amount of advancing / retreating drive of the electromagnetic movable rod between approaching and separating, and a connecting means that provides arc-shaped cam grooves for each electromagnetic movable rod on the rotating disk and slides an operating arm provided on the electromagnetic movable rod into each cam groove, and the rotation of the rotating disk drives the magnetic pole end faces of the electromagnetic movable rods to move closer and further away via the operating arms in the guide grooves. [Effects of the Invention]

[0008] The electric motor of the present invention controls the magnetic resistance experienced by the electromagnetic cylinder and electromagnetic movable rod of the stator by adjusting the inter-pole gap between the electromagnetic movable rod and the permanent magnet by moving the electromagnetic movable rod back and forth using the advancing / retracting drive mechanism in response to changes in the magnetic resistance (iron loss (eddy current and hysteresis) and copper loss (back electromotive force) in the magnetic circuit) experienced by the electromagnetic cylinder and electromagnetic movable rod of the stator due to the magnetic flux density generated by the permanent magnet (hereinafter referred to as PM) of the rotor. That is, the adjustment control of the magnetic pole gap by this electromagnetic moving rod operates the electromagnetic moving rod forward during acceleration or climbing a slope to narrow the magnetic pole gap with the permanent magnet, increasing the magnetic flux density of the facing magnetic field and generating high torque at low speeds.On the other hand, when the rotation speed increases, the electromagnetic moving rod is moved backward by the advancing / retreating drive mechanism to widen the magnetic pole gap between the permanent magnet and the electromagnetic moving rod, moving it to a state with low magnetic flux density, achieving high speed rotation with low magnetic resistance and exhibiting the excellent effect of reducing power consumption.

[0009] Control of the electromagnetic movable rod by the advancing / retreating drive mechanism determines the degree of displacement of the gap between the magnetic poles of the electromagnetic movable rod of the electromagnet and the rotor's permanent magnet within the rotor rotation speed range Cn from Xo to Xc, as shown in Figure 8. This automatically achieves optimized "torque versus rotation speed RPN" conditions for low speed / high torque and high speed / low torque. In other words, at low rotation speeds, the advancing / retreating drive mechanism narrows the gap between the magnetic poles, increasing the magnetic flux density and generating high torque as a result.

[0010] Furthermore, in order to precisely control the motor's power running, coasting, and regeneration (braking), the present invention preferably automatically controls the inter-pole gap by the advance / retract drive mechanism in accordance with the rotational speed of the rotor. In other words, the present invention makes it possible to optimize "torque versus rotational speed" by adjusting the advance / retraction of only the electromagnetic movable rod to deal with changes in the magnetic flux density generated between the PM and the electromagnetic cylinder (electromagnet) and the electromagnetic movable rod using the advance / retract drive mechanism. Furthermore, the present invention, for example, fixes the rotor itself or the stator itself without allowing it to move back and forth in the radial direction, thus avoiding such structural complications. In the case of the stator, this eliminates the need to operate the electromagnetic coil, stabilizing wiring maintenance, and in the case of the rotor, completely eliminates the need for divided expansion and contraction of the permanent magnet, thereby advantageously enabling the stabilization of overall maintenance. [Brief explanation of the drawings]

[0011] [Figure 1]1A and 1B are a front explanatory view (1) of a partial cross section showing an outer rotor type (inner ring type PS) electric motor according to a first embodiment of the present invention, and a perspective front explanatory view (2). [Figure 2] 2 is a perspective front explanatory view (1) showing only the stator of the electric motor shown in FIG. 1; FIG. 3 is a perspective front explanatory view (2) showing only the stator and rotor; and FIG. 3 is a perspective front explanatory view (3) showing the entire stator, rotor, and forward / backward drive mechanism. [Figure 3] FIG. 1 shows an explanatory front view (1) of the electric motor shown in FIG. 1, in which the rod pole is operated by a forward / backward drive mechanism to minimize the opposing surface gap between the electromagnetic pole end surface at the tip of the rod pole and the pole surface of the permanent magnet, and FIG. 2 shows an explanatory front view (2) of the electric motor shown in FIG. 1, in which the opposing surface gap between the electromagnetic pole end surface at the tip of the rod pole and the pole surface of the permanent magnet is maximized. [Figure 4] FIG. 10 is a front explanatory view, partly in section, showing an inner rotor type (outer ring type PS) electric motor according to a second embodiment of the present invention. [Figure 5] 5A is a perspective front explanatory view showing only the stator of the electric motor shown in FIG. 4; FIG. 5B is a perspective front explanatory view showing only the stator and rotor; and FIG. 5C is a perspective front explanatory view showing the entire stator, rotor, and forward / backward drive mechanism. [Figure 6] FIG. 5 is a front view (1) of the electric motor shown in FIG. 4, showing a state in which the rod pole is operated by a forward / backward drive mechanism to minimize the opposing surface gap between the electromagnetic pole end surface at the tip of the rod pole and the pole surface of the permanent magnet, and FIG. 5 is a front view (2) of the electric motor shown in FIG. 4, showing a state in which the opposing surface gap between the electromagnetic pole end surface at the tip of the rod pole and the pole surface of the permanent magnet is maximized. [Figure 7] This is a graph showing the drive characteristics of motors required for automobiles and railways. [Figure 8] 1 is a graph showing the relationship (actual measured values) between the rotor permanent magnets and the rod magnetic poles of the stator electromagnets, the gap between the magnetic poles, and the rotor rotation speed (RPM) verified in Examples 1 and 2. DETAILED DESCRIPTION OF THE INVENTION

[0012] The electric motor of the first embodiment is shown in FIGS. The electric motor of the first embodiment is an outer rotor type (outer ring type PS) electric motor that includes an outer rotor 10 in which the axial center portion 14 of an iron core 13 is fixedly connected to a rotary drive shaft 11 and permanent magnets 12 are fixedly arranged along the outer periphery of the iron core 13, as shown in Figures 1 and 3, and a stator 20 in which electromagnets 21 are arranged in the circumferential direction of a perfect circle with a predetermined inter-pole gap relative to the magnetic poles of the permanent magnets 12 on the outside of the rotor 10.

[0013] The stator 20 has the electromagnets 21 arranged along the radial direction of a circular base 24 of the stator 20. Each electromagnet 21 has an electromagnetic cylinder 22 fixedly supported on the circular base 24, an electromagnetic coil 25 attached to the outer periphery of the electromagnetic cylinder 22, and an electromagnetic movable rod 23 fitted in the electromagnetic cylinder 22 so as to be able to slide back and forth on the outer periphery thereof. The electromagnetic movable rod 23 is connected to an advance / retract drive mechanism 30 which varies the gap between the opposing surfaces of the electromagnetic movable rod 23 and the permanent magnet 12 in accordance with the rotation speed of the rotor 10 .

[0014] The advance / retreat drive mechanism 30 of this example detects changes in the rotation speed and magnetic flux density of the rotor and reversibly operates a drive device 32 such as a small motor, a solenoid mechanism, or an air cylinder mechanism to change the inter-pole gap (air gap) between the permanent magnet 12 and the electromagnetic movable rod 23 when their magnetic poles face each other, from the minimum inter-pole gap Xo at the start of rotation as shown in FIG. 2(1) to the optimum inter-pole gap Xc at which loss is minimized at maximum rotation speed as shown in FIG. 2(2).

[0015] The forward / backward drive mechanism 30, which changes the inter-pole gap (air gap) when the magnetic poles of the permanent magnet 12 and the electromagnetic movable rod 23 face each other, has a double doughnut-shaped rotating disk 31 rotatably disposed on the outer periphery of the stator 20. The rotating disk 31 is driven to rotate forward and backward by a small rotary motor 32 that detects changes in magnetic flux density according to the rotational speed of the rotor 10 and controls reversible rotation by a predetermined amount accordingly. The rotating disk 31 has arc-shaped cam grooves 33 of 0 to 80 degrees arranged on both sides of the double doughnut disk, the same number as the electromagnetic movable rods 23, and pin-shaped operating arms 34 formed on the bases 23-1 of the rear end faces of the electromagnetic movable rods 23 are inserted into the cam grooves 33 to connect them. The rotating disk 31 is rotated by a small rotary motor 32, which rotates the cam grooves 33 and causes the electromagnetic movable rods 23 to move slightly back and forth via the operating arms 34. This slight movement forward and backward varies the inter-pole gap (air gap), and can be precisely varied from the minimum inter-pole gap Xo at the start of rotation described above to the optimum inter-pole gap Xc at which loss is minimized at maximum speed rotation. The cam groove 33 is not limited to the arc shape of this example, but may be a diagonal straight cam groove. In short, it may be formed in accordance with the spacing operation range in which the electromagnetic movable rod 23 is advanced and retreated by the operating arm 34.

[0016] Incidentally, in the above-mentioned Example 1 1. Rotor 10 has a radius of 18 cm. 2. Specifications of permanent magnet 12: Neodymium magnet, curved piece, 1cm diameter, 2cm length, weight 11.56g, attractive force = 4061gf, surface magnetic flux density = 5327Gauss 3. Radius of circular base 24 of stator 20 = 15 cm, weight = approximately 2800 g 4. Electromagnet 21 specifications: Total length = 6 cm, 0.6 mm diameter copper wire length 70 m, core diameter = 1.3 cm, material = mild steel (electromagnetic steel plate)

[0017] In the verification experiment of Example 1, the air gap at start-up was 2.0 mm, the rotation speed was 552 rpm, and the power consumption was 4.7 W. As the air gap expanded with rotation, it reached a maximum of 4.5 mm, at which point the rotation speed was 723 rpm and the power consumption was 2.7 W. In other words, the rotation speed increased by approximately 30% and the power consumption decreased by approximately 40%. As a result, the high-speed navigation performance of the motor is roughly (100 + 30%) / (100 - 40%), or approximately double, compared to when maximum torque is generated. However, there are various factors involved, such as consumption by air conditioners and other electrical appliances, and it goes without saying that calculations must be made according to the situation.

[0018] Next, a second embodiment of the present invention will be described with reference to FIGS. The electric motor of Example 2 is an inner rotor type (inner ring type PS) electric motor provided with an inner rotor 100 in which the axial center portion 104 of an iron core 103 is connected and fixed to a rotating drive shaft 101 and permanent magnets 102 are fixedly arranged along the outer periphery of the iron core 103, and a stator 200 in which electromagnetic coils 205 of electromagnets 201 are arranged in the circumferential direction of a perfect circle with a predetermined inter-pole gap relative to the magnetic poles of the permanent magnets 102 on the outside of the rotor 100.

[0019] The stator 200 has the electromagnets 201 arranged radially on a circular base 204 of the stator 200. Each electromagnet 201 is composed of an electromagnetic cylinder 210 fixedly supported on the circular base 204, an electromagnetic coil 205 wound around the outer periphery thereof, and an electromagnetic movable rod 220 arranged within the electromagnetic cylinder 210 so that its outer periphery can slide back and forth. Each electromagnetic movable rod 220 is connected to an advance / retract drive mechanism 300 that varies the gap between the opposing surfaces of the permanent magnet 102 and the electromagnetic movable rod 220 in accordance with the rotation speed of the rotor 100 and the change in the magnetic flux density.

[0020] The advance / retract drive mechanism 300 reversibly rotates a drive device 302 such as a small motor, a solenoid mechanism, or an air cylinder mechanism in response to changes in the rotation speed of the rotor 100 and the magnetic flux density, thereby varying the inter-pole gap (air gap) between the permanent magnet 102 and the electromagnetic movable rod 220 when their magnetic poles face each other, from the minimum inter-pole gap Xo at the start of rotation as shown in FIG. 6(1) to the optimum inter-pole gap Xc at which loss is minimized at maximum rotation speed as shown in FIG. 6(2).

[0021] The advance / retract drive mechanism 300, which adjusts the inter-pole gap (air gap) between the permanent magnet 102 and the electromagnetic movable rod 220 when the magnetic poles face each other, has a double doughnut-shaped rotating disk 301 rotatably disposed on the outer periphery of the stator 200. The rotating disk 301 is driven to rotate forward and backward by a driving device 302, such as a small motor, solenoid mechanism, or air cylinder mechanism, which controls a predetermined amount of reversible rotation in response to changes in the rotation speed of the rotor 100 and the magnetic flux density. The rotating disk 301 has an array of arc-shaped cam grooves 303 of 0 to 80 degrees, the same number as the electromagnetic movable rods 203, formed on each of the double doughnut disks, and a pin-shaped operating arm 304 formed on a base 203-1 on the rear end surface of the electromagnetic movable rod 203 is slidably inserted into the cam grooves 303 for connection. The rotating disk 301 is rotated by the driving device 302 to rotate the cam groove 303, thereby slightly moving the electromagnetic movable rod 203 forward and backward via the operating arm 304. This slight forward and backward movement varies the inter-pole gap (air gap), and changes it with high precision from the minimum inter-pole gap Xo at the start of rotation to the optimum inter-pole gap Xc at which loss is minimized at maximum speed rotation. The cam groove 303 is not limited to the arc shape of this example, but may be a diagonal straight cam groove. In short, it may be formed in accordance with the spacing operation range in which the electromagnetic movable rod 203 is advanced and retreated by the operation arm 304.

[0022] Incidentally, in the above-mentioned Example 2 1. Rotor 100 has a radius of 18 cm. 2. Specifications of permanent magnet 102: Neodymium magnet, curved piece, 1cm diameter, 2cm length, weight 11.56g, attractive force = 4061gf, surface magnetic flux density = 5327Gauss 3. Radius of circular base 204 of stator 200 = 15 cm, weight = approximately 2800 g 4. Electromagnet 201 specifications: Total length = 6 cm, 0.6 mm diameter copper wire length = 70 m, core diameter = 1.3 cm, core material = soft iron (electromagnetic steel sheet)

[0023] In the verification experiment for Example 2, the air gap at start-up was 2.0 mm, the rotation speed was 552 rpm, and the power consumption was 4.7 W. As the air gap expanded with rotation, it reached a maximum of 4.5 mm, at which point the rotation speed was 723 rpm and the power consumption was 2.7 W. In other words, the rotation speed increased by approximately 30% and the power consumption decreased by approximately 40%. As a result, the high-speed navigation performance of the motor is roughly (100 + 30%) / (100 - 40%), or approximately double, compared to when maximum torque is generated. However, there are various factors involved, such as consumption by air conditioners and other electrical appliances, and it goes without saying that calculations must be made according to the situation. [Industrial Applicability]

[0024] The electric motor of the present invention allows the rotor and stator to be freely arranged in any orientation, such as vertical, horizontal (horizontal), or oblique, and is also slim and maintenance-free. Its range of applications is immeasurable, making it usable for a wide variety of small, large, and ultra-small drive motors used in bicycles, automobiles, electric vehicles, airplanes, drones, etc., as simple household generators or drive motors, and as various industrial generators or drive motors, and its versatility is immeasurable, making it a great contribution to the electric motor industry. [Explanation of symbols]

[0025] Xo: Minimum magnetic pole gap Xc: Optimal fastest magnetic pole gap 10: Outer rotor 100: Inner rotor 11, 101: Rotating drive shaft 12, 101: Permanent magnet 13, 103: Iron core 14, 104: Axis center 20, 200: Stator 21, 201: Electromagnet (consisting of an electromagnetic coil, an electromagnetic cylinder, and an electromagnetic movable rod) 24, 204: Circular base of stator 25, 205: Electromagnetic coil 22, 202: Electromagnetic cylinder 23, 203: Electromagnetic moving rod 23-1, 203-1: Base of the rear end face of the electromagnetic movable rod 30, 300: Advance / retreat drive mechanism (consisting of a small rotary motor, a double doughnut-shaped rotary disk, a cam groove, and an operating arm) 31, 301: Double donut disc type rotating disc 32, 302: Drive devices such as small motors, solenoid mechanisms, and air cylinder mechanisms 33, 303: Cam groove 34, 304: Control arm

Claims

1. An electric motor comprising: a rotor whose axis is connected to a rotary drive shaft and whose permanent magnets are arranged circumferentially; and a stator in which the electromagnetic poles of electromagnets are arranged circumferentially on the inner or outer periphery of the rotor so as to face the pole faces of the permanent magnets with a predetermined gap, wherein the electromagnetic poles are composed of an electromagnetic cylinder whose outer periphery is wound with a coil, and an electromagnetic movable rod slidably provided within the electromagnetic cylinder, and the electromagnetic pole end face of the electromagnetic movable rod is connected to a forward / backward drive mechanism which varies the facing surface gap between the pole face of the permanent magnet and the tip of the electromagnetic pole end face in accordance with the rotational speed of the rotor.

2. 2. The electric motor according to claim 1, wherein the advance / retract drive mechanism comprises a rotating disk that reversibly operates one of a small motor, a solenoid mechanism, or an air cylinder mechanism in accordance with the rotational speed of the rotor and the electromagnetic density to vary the amount of advance / retract drive of the electromagnetic movable rod toward or away from the rotor, and a connecting means that provides arc-shaped cam grooves for each electromagnetic movable rod on the rotating disk and that slides an operating arm provided on the electromagnetic movable rod into each cam groove, and that drives the magnetic pole end faces of the electromagnetic movable rod toward or away from the rotor via the operating arms in the guide grooves by the rotation of the rotating disk.

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