Rice milling machine
The rice milling machine addresses low torque issues by using a rotor with enhanced dimensions and components for direct power transmission, enabling efficient milling of larger rice quantities with reduced noise and vibration.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- YAMAMOTO ELECTRIC
- Filing Date
- 2024-12-11
- Publication Date
- 2026-06-23
AI Technical Summary
Conventional rice milling machines with direct-drive motors have low torque, limiting them to milling small quantities of rice and risking motor burnout with increased torque or speed.
A rice milling machine design featuring a motor with a rotor that is three times longer in the perpendicular direction than in the axial direction, incorporating multiple magnets, coils, and brushes, directly transmitting power to rotating blades without belts, enabling high torque and speed for large rice quantities.
The design allows for milling larger amounts of rice efficiently with reduced noise and vibration, achieving high torque and speed for effective bran removal.
Smart Images
Figure 2026101701000001_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to a rice milling machine.
Background Art
[0002] There is known a rice milling machine for milling rice grains for household use. The rice milling machine mills, for example, brown rice into white rice. In such a rice milling machine, the rice grains are stirred and the bran is removed from the rice grains by the friction between the rice grains. To stir the rice grains, the rice milling machine has a rotating blade and a motor for rotating the rotating blade.
[0003] When the rotational power of the motor is transmitted to the rotating blade via a pulley, a belt, or the like, particularly when the rotation of the motor becomes fast, vibration and noise may occur due to the belt or the like. In order to solve such problems, it has been considered to directly transmit the rotational power of the motor to the rotating blade without using a pulley, a belt, or the like. A shaft rotated by the motor is directly connected to the rotating blade. Such a motor is called a direct drive motor.
Prior Art Documents
Patent Documents
[0004]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0005] Conventional rice milling machines with direct-drive motors have low torque for rotating the blades, so they can only mill about two cups of rice at a time. Conventional rice milling machines with direct-drive motors have difficulty milling large quantities of rice at once. Simply trying to rotate the motor with high torque and the rotational speed required for milling may result in the motor not rotating properly or the current flowing to the motor becoming too large, causing it to burn out. The purpose of this disclosure is to provide a rice milling machine in which a direct-drive motor can rotate the blades with the rotational speed and torque required for milling. [Means for solving the problem]
[0006] The rice milling machine disclosed herein is Motor and, A shaft extending in the axial direction and rotated by the motor, A rotating blade directly connected to the aforementioned shaft, The system comprises a first container that houses the rotating blades inside, The motor comprises a stator and a rotor that rotates relative to the stator and is directly connected to the shaft. The length of the rotor in the direction perpendicular to the axial direction is three times or more the length of the rotor in the axial direction. [Brief explanation of the drawing]
[0007] [Figure 1] Figure 1 is a cross-sectional view of a rice milling machine according to one embodiment. [Figure 2] Figure 2 is a photograph showing the motor, the first shaft, and the rotating disc. [Figure 3] Figure 3 is a photograph showing coupling. [Figure 4] Figure 4 is a photograph showing the second shaft placed inside the first container. [Figure 5] Figure 5 is a photograph showing the rotating blades placed inside the first container. [Figure 6] Figure 6 is a photograph showing a rotating blade. [Figure 7]Figure 7 is a top view showing the inside of the motor. [Modes for carrying out the invention]
[0008] One embodiment of the present disclosure relates to the following [1] to [4]. [1] Motor and, A shaft extending in the axial direction and rotated by the motor, A rotating blade directly connected to the aforementioned shaft, The system comprises a first container that houses the rotating blades inside, The motor comprises a stator and a rotor that rotates relative to the stator and is directly connected to the shaft. A rice milling machine in which the length of the rotor in a direction perpendicular to the axial direction is three times or more the length of the rotor in the axial direction. [2] The rice milling machine according to [1], wherein the stator includes four or more magnets. [3] The rotor comprises 16 or more coils, as described in [1] or [2], for the rice milling machine. [4] The rice milling machine according to any one of [1] to [3], wherein the motor further comprises four or more brushes.
[0009] Hereinafter, an embodiment of this disclosure will be described with reference to the drawings. In the drawings attached to this specification, the scale and aspect ratios of the dimensions may be changed and exaggerated from those of the actual objects for the sake of illustration and ease of understanding. Some components shown in some drawings may be omitted in other drawings.
[0010] In this specification, terms such as "parallel," "orthogonal," and "identical," as well as values of length and angle, which specify shapes, geometric conditions, and their degrees, are to be interpreted not in a strict sense, but to include a range that can be expected to function similarly.
[0011] FIG. 1 shows a cross-sectional view of a rice milling machine 10 according to an embodiment. The rice milling machine 10 removes bran from rice grains to mill the rice. The rice milling machine 10 is used at home. As shown in FIG. 1, the rice milling machine 10 includes a housing 11, a lid 12, a first container 13, a second container 14, a first shaft 15, a rotating disk 16, a coupling 17, a second shaft 18, a rotating blade 19, and a motor 20.
[0012] The housing 11 houses the first container 13, the second container 14, the first shaft 15, the rotating disk 16, the coupling 17, the second shaft 18, the rotating blade 19, and the motor 20 therein. The housing 11 is provided with an opening at the upper part. The lid 12 is provided so as to close the opening of the housing 11. The lid 12 is openable and closable. In the closed state, the lid 12 closes the opening of the housing 11 and suppresses the rice grains from jumping out of the inside of the housing 11. In the open state, the rice grains can be put in and taken out of the inside of the housing 11 through the opening of the housing 11.
[0013] The first container 13 stores the rice grains inside the housing 11. The first container 13 is provided with an opening at the upper part. The opening of the first container 13 faces the opening of the housing 11. The first container 13 houses the rotating blade 19 inside. The first container 13 is provided with a plurality of holes. The maximum diameter of the holes is smaller than the minimum diameter of the rice grains. For example, the maximum diameter of the holes may be 3 mm or less, or may be 1 mm or less. With the holes being such a size, it is difficult for the rice grains to come out of the holes and the bran is discharged. The first container 13 may be formed of a net-like member or may be formed of a punching plate.
[0014] The second container 14 stores the bran that comes out of the holes of the first container 13. The second container 14 is arranged so as to house the first container 13. Each dimension of the second container 14 is larger than each dimension of the first container 13. The second container 14 is provided with an opening at the upper part.
[0015] The first shaft 15 transmits the rotational power of the motor 20 to the turntable 16. The shaft 15 is rotated by the motor 20. The first shaft 15 extends in the axial direction X.
[0016] The turntable 16 is directly connected to the first shaft 15. The turntable 16 transmits the rotational power of the motor 20 to the second shaft 18 via the coupling 17. The turntable 16 rotates in conjunction with the rotation of the first shaft 15. Figure 2 shows a photograph of the turntable 16 connected to the first shaft 15. As shown in Figure 2, the turntable 16 has a projection 16A for connection with the coupling 17.
[0017] The coupling 17 connects to the turntable 16. The coupling 17 transmits the rotation of the turntable 16 to the second shaft 18. The coupling 17 is directly connected to the second shaft 18. Figure 3 shows a photograph of the coupling 17 provided at the bottom of the first container 13. As shown in Figure 3, the coupling 17 has a receiving portion 17A. The turntable 16 and the coupling 17 are connected when the receiving portion 17A engages with the protrusion 16A of the turntable 16.
[0018] Figure 4 shows a photograph of the second shaft 18 positioned inside the first container 13. As shown in Figure 4, the second shaft 18 extends inside the first container 13. The second shaft 18 extends in the same axial direction X as the first shaft 15. The second shaft 18 is directly connected to the coupling 17 via the bottom surface of the first container 13. The second shaft 18 rotates in conjunction with the rotation of the coupling 17. The second shaft 18 is directly connected to the rotor blades 19. The rotation of the second shaft 18 causes the rotor blades 19 to rotate.
[0019] Figure 5 shows a photograph of the rotating blade 19. As shown in Figure 5, the rotating blade 19 is located inside the first container 13. The rotating blade 19 agitates the rice grains contained in the first container 13 by rotating. The friction between the agitated rice grains removes the bran from the rice grains. The rotating blade 19 is directly connected to the second shaft 18. The rotation of the first shaft 15 causes the rotating blade 19 to rotate. The first shaft 15 is directly connected to the turntable 16, the turntable 16 is connected to the coupling 17, the coupling 17 is directly connected to the second shaft 18, and the rotation of the second shaft 18 causes the rotating blade 19 to rotate. The rotating blade 19 is directly connected to the first shaft 15 via the turntable 16, the coupling 17 and the second shaft 18. Figure 6 shows a photograph of an example of the rotating blade 19. As shown in the example in Figure 6, the rotating blade 19 may include a base 19A that extends non-parallel to the axial direction X, and a plurality of blade portions 19B extending from the base 19A. The base 19A supports the blade portions 19B and rotates with the rotation of the second shaft 18. The blade portions 19B move with the rotation of the base 19A to agitate the rice grains. The rotating blade 19 may have any configuration and shape that is capable of agitating the rice grains contained in the first container 13, and is not limited to the illustrated example.
[0020] The motor 20 transmits rotational power to the rotating blades 19 via the first shaft 15, the turntable 16, the coupling 17, and the second shaft 18. To directly transmit the rotational power of the motor 20 to the rotating blades 19, there are no pulleys, belts, or the like between the motor 20 and the turntable 16. The motor 20 is a so-called direct-drive motor. As shown in Figure 2, the motor 20 has a flattened shape.
[0021] Figure 7 shows an internal top view of the motor 20. As shown in Figure 7, the motor 20 includes a stator 21, a rotor 22, a commutator 23, and brushes 24.
[0022] The stator 21 is a fixed component. The stator 21 interacts with the rotor 22. In the example shown in Figure 7, the stators 21 are arranged circumferentially at positions radially separated with respect to the axial direction X from which the first shaft 15 extends. There may be four or more stators 21. The stators 21 may include magnets 21A. The magnets 21A may be permanent magnets, as in the illustrated example, or they may be electromagnets.
[0023] The rotor 22 is a component that rotates relative to the stator 21. The rotor 22 is directly connected to the first shaft 15. The rotor 22 rotates around the axial direction X from which the first shaft 15 extends. As the rotor 22 rotates, the rotational power of the motor 20 is directly transmitted to the rotating blades 19 via the first shaft 15, etc.
[0024] The length of the rotor 22 along the axial direction X, in other words, the thickness of the rotor 22, may be 25 mm or less. The length of the rotor 22 along the direction perpendicular to the axial direction X, in other words, the diameter of the rotor 22, may be 75 mm or more. The rotor 22 has a flattened shape with a diameter that is sufficiently long relative to its thickness. Specifically, the length of the rotor 22 along the direction perpendicular to the axial direction X is at least three times, preferably four times, the length of the rotor 22 along the axial direction X.
[0025] The rotor 22 may include a core 22A and coils 22B. The core 22A includes a plurality of teeth that form the core of the coils 22B. The plurality of teeth are arranged circumferentially with respect to the axial direction X. The coils 22B are formed by winding a wire around the teeth of the core 22A. In the example shown in Figure 7, the coils 22B are formed by winding a wire across four teeth of the core 22A. When current flows through the coils 22B, the coils 22B function as an electromagnet. The current-carrying coils 22B interact with the stator 21. The rotor 22 may include 16 or more coils 22B. Correspondingly, the number of teeth of the core 22A may also be 16 or more. The number of slots formed between the teeth of the core 22A may also be 16 or more. The winding of the coils 22B is, for example, copper wire.
[0026] The commutator 23 controls the order and direction of the current flowing through the coil 22B. The ends of the windings of the coil 22B are each connected to a different commutator 23. The commutator 23 rotates together with the rotor 22.
[0027] The brushes 24 contact the commutator 23, thereby allowing current to flow through the commutator 23 to the coil 22B. The brushes 24 are connected to a power supply (not shown). As the rotor 22 rotates, the brushes 24 contact different commutators 23. There may be four or more brushes 24. As shown in Figure 7, the brushes 24 are arranged circumferentially with respect to the axial direction X. In the circumferential direction, positive and negative brushes 24 are arranged alternately.
[0028] A DC voltage, obtained by rectifying an AC voltage, is applied to the motor 20. Specifically, a DC voltage is applied between the positive and negative brushes 24. A maximum DC voltage of 142V is applied between the positive and negative brushes 24 of the motor 20. The voltage applied to the motor 20 is controlled by a circuit board (not shown), and the motor's rotation speed is variably controlled by pulse width modulation.
[0029] The process by which the rice milling machine 10 removes bran from rice grains and mills the rice is described below. The lid 12 is opened and rice grains are placed into the first container 13 inside the housing 11. The lid 12 is closed and voltage is applied to the motor 20. Current flows through the coil 22B and interacts with the magnet 21A. The rotor 22 of the motor 20 rotates. The rotation of the rotor 22 is directly transmitted to the rotating blades 19 via the first shaft 15, the turntable 16, the coupling 17, and the second shaft 18. The rotating blades 19 rotate inside the first container 13. The rotating blades 19 agitate the rice grains inside the first container 13. The friction between the agitated rice grains removes the bran from them. The removed bran exits through the holes in the first container 13 and is collected in the second container 14. The amount of bran removed from the rice grains varies depending on the time the rotating blades 19 are rotated and the rotation speed of the rotating blades 19. The rotating blades 19 are rotated for a time and at a rotation speed that allows the desired amount of bran to be removed from the rice grains. The lid 12 is opened and the rice grains from which the bran has been removed are taken out of the first container 13.
[0030] In the rice milling machine 10 of this embodiment, the rotor 22 is directly connected to the first shaft 15, and the rotating blades 19 are directly connected to the first shaft 15 via the turntable 16, coupling 17, and second shaft 18. The rotational power of the motor 20 is directly transmitted to the rotating blades 19 without the need for pulleys, belts, etc. This eliminates vibrations and noise caused by belts, etc. Furthermore, in the rice milling machine 10 of this embodiment, the length of the rotor 22 in the direction perpendicular to the axial direction X is at least three times the length of the rotor 22 in the axial direction X. The rotor 22 has a flattened shape with respect to the axial direction X. Because the length of the rotor 22 in the direction perpendicular to the axial direction X is sufficiently long, the rotational torque of the rotor 22 can be increased. The rotational torque of the rotating blades 19 is also increased. The motor 20 can rotate the rotating blades 19 of the rice milling machine 10 at the rotational speed and torque required for rice milling. Even if the first container 13 contains a large amount of rice grains, the rotating blades 19 can be rotated to mill a large amount of rice grains at once, for example, 5 go (approximately 150g) of rice grains.
[0031] The stator 21 contains four or more magnets 21A. Because the stator 21 contains many magnets 21A, the rotational speed of the rotor 22 is slower, but the torque of the rotor 22 is increased. The rotational torque of the rotating blades 19 is also increased. The motor 20 can rotate the rotating blades 19 of the rice milling machine 10 with high torque.
[0032] The rotor 22 contains 16 or more coils 22B. Because the rotor 22 contains many coils 22B, the rotational speed of the rotor 22 is slower, but the torque of the rotor 22 is increased. The rotational torque of the rotating blades 19 also increases. The motor 20 can rotate the rotating blades 19 of the rice milling machine 10 with high torque.
[0033] The motor 20 includes four or more brushes 24. With four or more brushes than with two brushes, more current can flow through the coil 22B in a parallel circuit. The coil 22B through which current flows interacts with the stator 21. As more current flows through the coil 22B interacting with the stator 21, the rotational speed and torque of the rotor 22 increase. The rotational speed and torque of the rotating blades 19 also increase. The motor 20 can rotate the rotating blades 19 of the rice milling machine 10 at the rotational speed and torque required to mill a large amount of rice grains, for example, 5 go (approximately 1500g) of rice grains, with its high rotational speed and torque.
[0034] Conventional rice milling machines, especially those small enough for home use, have difficulty incorporating a direct-drive motor capable of rotating the shaft with sufficient rotational speed and torque. In this embodiment, by making the length of the rotor 22 in the direction perpendicular to the axial direction X at least three times the length of the rotor 22 in the axial direction X, including four or more magnets 21A in the stator 21, including sixteen or more coils 22B in the rotor 22, and / or including four or more brushes 24 in the motor 20, such a direct-drive motor can be realized, even when the machine is small enough for home use.
[0035] The embodiments of this disclosure are not limited to those described above, but include various modifications that a person skilled in the art could conceive, and the effects of this disclosure are not limited to those described above. Various additions, modifications, and partial deletions are possible, provided that they do not depart from the conceptual idea and spirit of this disclosure derived from the claims and their equivalents. [Explanation of symbols]
[0036] 10 Rice milling machine 11 cabinets 12 Lid 13 1st container 14 Second container 15. First shaft 16-turn disc 17 Couplings 18. Second shaft 19 Rotating blades 20 motors 21 status 21A Magnet 22 rotors 22A core 22B coil 22B core 23 Commutator 24 brushes
Claims
1. Motor and, A shaft extending in the axial direction and rotated by the motor, A rotating blade directly connected to the aforementioned shaft, The system comprises a first container that houses the aforementioned rotating blades inside, The motor comprises a stator and a rotor that rotates relative to the stator and is directly connected to the shaft. A rice milling machine in which the length of the rotor in a direction perpendicular to the axial direction is three times or more the length of the rotor in the axial direction.
2. The rice milling machine according to claim 1, wherein the stator includes four or more magnets.
3. The rice milling machine according to claim 1, wherein the rotor includes 16 or more coils.
4. The rice milling machine according to claim 1, wherein the motor further includes four or more brushes.