JP5459858B2 - Rice mill - Google Patents

Description

  The present invention relates to a small rice mill for home use suitable for milling a relatively small amount of rice.

  Conventionally, as this type of rice mill, the rice in the rice mill container is stirred by a milled rice body rotated by an electric motor, and this rice is rubbed against the net-like part of the side peripheral part of the rice mill container. A table-type rice mill used in homes and the like that scrapes off rice cake and the like to make white rice is known (see, for example, Patent Document 1). The said rice milling container is accommodated in the rice bran receptacle so that attachment or detachment is possible. Then, the rice cake or the like scraped off from the rice is discharged out of the net-like portion and is stored in the rice cake receptacle. The rice mill container accommodates brown rice, white rice that has passed time after milling, or the like.

JP 2008-229558 A

  In such a rice mill, the airflow that has flowed out of the mesh portion due to centrifugal force along with the ridges or the like flows into the mesh portion from the upper portion of the mesh portion. For this reason, there is a possibility that a part of the rice cake and the like once discharged from the rice milling container adheres to the mesh portion. In this state, when the rice milling container is lifted, there is a risk that the slag and the like may fall and soil the floor and table.

  The present invention solves the above problems and removes rice cake etc. adhering to the rice milling container, so that the rice milling machine which can prevent rice cake etc. from falling from the rice milling container when taking out the rice that has been polished. The purpose is to provide.

  A rice mill according to claim 1 of the present invention includes a rice mill container in which a hole that does not pass rice grains and a rice cake is formed, and a rice mill body that rotates in the rice mill container and stirs the rice in the rice mill container. In the rice mill having a motor for rotating the rice mill and a control circuit for driving and controlling the motor by PWM, the control circuit adjusts a duty ratio to control the rotational speed of the rice mill. And an end step of rotating the electric motor for a short time at a duty ratio higher than the duty ratio in the rotation control step.

  Further, the rice mill according to claim 2 of the present invention is the rice mill according to claim 1, wherein the time of the end step is set to be equal to or longer than the time for the rice mill to make one rotation.

  According to a third aspect of the present invention, there is provided a method for controlling a rice mill, comprising: a rice mill container in which a hole for allowing rice grains to pass through and a rice cake to pass through is formed; and the rice in the rice mill container is rotated in the rice mill container. In a rice mill control method having a rice mill to be stirred, an electric motor for rotating the rice mill, and a control circuit for driving and controlling the motor by PWM, the control circuit supplies the electric motor in the rotation control step. The rotational speed of the milled rice is controlled by adjusting the duty ratio of the electric power to be rotated, and the electric motor is rotated for a short time at a duty ratio higher than the duty ratio in the rotation control process in the end process following the rotation control process. Is.

  Furthermore, the control method of the rice mill according to claim 4 of the present invention is the method according to claim 3, wherein the end step is executed for a time longer than the time for the rice mill to make one rotation.

  In the rice mill and the control method thereof according to the present invention, when the rice milling body in the rice milling container is rotated by the electric motor, the rice in the rice milling container is stirred by the rice milling body. And the surface wrinkles of the rice in the said rice milling container are removed by rubbing with the inner surface of the said rice milling container. Further, the removed rice bran is discharged out of the rice milling container. And in an end process, by supplying electric power to the electric motor for a short time with a higher duty ratio than a rotation control process, while changing the air current which circulates inside and outside the rice milling container, vibration is increased. Thereby, the wrinkles adhering to the outer surface of the rice milling container can be removed.

  And, since the time of the end step is set to be more than the time for the rice mill to make one rotation, the rice also revolves at a high speed in the rice mill container at least once, so that the rice is raised to a high position of the rice mill container, Since vibration can be generated in a wide range of the rice milling container, it is possible to reliably remove the soot and the like from the rice milling container.

It is sectional drawing of the rice mill which shows one Embodiment of this invention. It is the side view which notched a part of rice milling container same as the above. It is a block diagram of the electric circuit of a rice mill. It is a graph which shows the change of the power supply in a starting process similarly. It is a graph which shows notionally the change of the revolution speed of the rice in a starting process. It is a graph which shows the change of the rotational speed of the milled rice body after the rotation control process of a three-part milling mode. It is a graph which shows the change of the rotational speed of the polished rice body after the rotation control process of a quintuple milling mode. It is a graph which shows the change of the rotational speed of the polished rice body after the rotation control process of a 7-minute sowing mode. It is a graph which shows the change of the rotational speed of the polished rice body after the rotation control process of white rice mode. It is a graph which shows the change of the rotational speed of the polished rice body after the rotation control process of the upper white rice mode. It is a graph which shows the change of the power supply in an end process. It is explanatory drawing which shows the motion of the rice at the time of completion | finish of a rotation control process. It is explanatory drawing which shows the motion of the rice at the time of an end process.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 13. In the present embodiment, front and rear and top and bottom are defined based on the posture of FIG. 1, and the left side of FIG. 1 is the front and the right side is the back. 1 is a rice mill of the present invention. The rice mill 1 includes a rice mill main body 2, a rice bran receptor 3, a rice mill container 4, a rice mill body 5, and a lid body 6.

  The rice mill main body 2 has an outer shell body 9 composed of an upper outer shell body 7 and a lower outer shell body 8. An attachment hole 7A is formed on the upper front side of the upper outer shell body 7, and the operation portion 10 is attached to the attachment hole 7A. In addition, on the rear side of the upper outer shell body 7, there is provided a storage recess 7 </ b> B having a bottomed cylindrical recess that opens upward. A through hole 7C is formed at the center of the bottom of the storage recess 7B. On the other hand, a mounting recess 8A is formed at the bottom of the lower outer shell 8. Then, the cord reel 11 is attached to the attachment recess 8A. In addition, a plurality of leg attachment portions 8 </ b> B are formed at the bottom of the lower outer shell body 8. Rubber legs 12 are attached to these leg attachment portions 8B, respectively. A drive mechanism 13 is accommodated in the outer shell body 9. The drive mechanism 13 includes a metal frame 14, a bearing case 15, an electric motor 16, a primary driven shaft 17, a small pulley 18, a large pulley 19, an endless drive belt 20, and a primary connection portion 21. And is configured. The electric motor 16 is attached to the front portion of the frame 14. The primary driven shaft 17 is pivotally supported on the rear portion of the frame 14. The small pulley 18 is attached to a rotating shaft of the electric motor 16 that extends downward through the frame 14. The large pulley 19 is attached to the lower end of the primary driven shaft 17 that extends downward through the frame 14. The drive belt 20 is stretched between the small pulley 18 and the large pulley 19. Further, the primary connection portion 21 is attached to the upper end of the primary driven shaft 17 that extends upward through the bearing case 15. A concave bearing insertion portion 14 </ b> A is formed at the rear portion of the frame 14. The bearing case 15 is attached to the upper surface of the frame 14 so as to cover the bearing insertion portion 14A. A concave bearing insertion portion 15A is formed at the center upper portion of the bearing case 15, and the bearing 22 is fitted and fixed to the bearing insertion portion 15A. On the other hand, another bearing 23 is also fitted and fixed to the bearing insertion portion 14A. The primary driven shaft 17 penetrating the frame 4 is pivotally supported by the pair of upper and lower bearings 22 and 23 so that the central axis thereof is in the vertical direction. Further, the primary connection portion 21 is exposed from the through hole 7C into the storage recess 7B.

  In the storage recess 7B, the cocoon receptor 3 for receiving the cocoon and germ removed from the rice or the oxidized layer removed from the surface of the rice is detachably inserted. This bag acceptor 3 is formed in a substantially bottomed cylindrical shape. A through hole 3B is formed at the center of the bottom 3A of the heel receptacle 3. The through hole 3B is formed coaxially with the through hole 7C corresponding to the through hole 7C of the storage recess 7B. Further, a cylindrical portion 3C is formed so as to extend upward from the through hole 3B and cover the outer periphery of the primary connection portion 21 and a secondary connection portion 31 described later.

  And the rice mill container 4 for accommodating rice is detachably inserted into the rice bran receptacle 3. This rice milling container 4 is configured to have a mesh portion 24, a bottom member 25, an upper edge member 26, and a disc portion 27. The mesh portion 24 includes a substantially cylindrical side peripheral portion 24A, a bottom portion 24B, and a curved portion 24C that smoothly connects them. The bottom member 25 is fixed to the lower portion of the mesh portion 24. The upper edge member 26 is fixed to the upper part of the mesh portion 24. Further, the disk portion 27 is provided inside the bottom of the mesh portion 24. A bearing cylinder portion 25A protruding upward is formed at the center of the bottom member 25, and a shaft hole 25B is formed at the upper end thereof. The bottom member 25 is provided with a cylindrical portion 25C formed in a short cylindrical shape. The cylindrical portion 25C is provided to position the rice milling container 4 with respect to the rice bran receptacle 3 and to prevent the removed rice bran etc. from entering the rice milling body 2 from the through hole 7C. . Then, the secondary driven shaft 29 is pivotally supported with respect to the bearing tube portion 25A through the shaft hole 25B. The central axis of the secondary driven shaft 29 that is pivotally supported by the bearing tube portion 25A is vertical. Further, an engagement shaft portion 30 having a square hexagonal cross section is attached to the upper end of the secondary driven shaft 29. On the other hand, a secondary connection portion 31 is attached to the lower end of the secondary driven shaft 29 corresponding to the primary connection portion 21. The primary connection portion 21 and the secondary connection portion 31 constitute a coupling 32 that transmits the rotation of the primary driven shaft 17 to the secondary driven shaft 29. On the other hand, a string-like grip 33 is swingably attached to the upper edge member 26.

  The disc part 27 is made of steel having a sufficient thickness. And the said disc part 27 is provided inside the said rice polishing container 4 so that the bottom part 24B of the said mesh-like part 24 may be covered from upper direction. The outer peripheral portion 27A of the disc portion 27 extends to the curved portion 24C of the mesh portion 24, and the outer peripheral portion 27A is curved upward and smoothly along the curved portion 24C. In addition, the said disk part 27 has a smooth surface in which a hole is not formed except the hole corresponding to the said bearing cylinder part 25A.

  The rice milling body 5 for agitating the rice in the rice milling container 4 is detachably attached to the engagement shaft portion 30 of the secondary driven shaft 29 in the rice milling container 4. The rice milling body 5 is located inside the rice milling container 4 when engaged with the engagement shaft portion 30. The milled rice body 5 includes a shaft body 34 and a pair of rod-shaped bodies 35. The shaft body 34 is coaxial with the engaging shaft portion 30, and thus with the secondary driven shaft 29 in a state of being engaged with the engaging shaft portion 30. Further, the rod-like body 35 is provided so as to protrude in a radial direction from the lower portion of the shaft body 34 with respect to the axial direction of the shaft body 34. The shaft body 34 is formed with an engagement hole portion 36 having a regular hexagonal cross section corresponding to the engagement shaft portion 30. The shaft hole 34 is engaged with the engagement hole portion 36 in a state in which the shaft body 34 is prevented from rotating with respect to the engagement shaft portion 30 and thus the secondary driven shaft 29. The rod-shaped body 35 is formed in a columnar shape from stainless steel or the like.

  The outer edge of the outer peripheral portion 27A of the disc portion 27 extends to the outside of the locus drawn by the tip 35A of the rod-like body 35. Further, the outer edge of the outer peripheral portion 27 </ b> A of the disc portion 27 is lower than the lower end 35 </ b> B of the rod-like body 35.

  Further, the lid 6 is detachably attached so as to cover the upper part of the storage recess 7 </ b> B, the koji receiver 3 and the rice milling container 4. In addition, this cover body 6 is comprised with the synthetic resin with the whole so that the inside of the said rice milling container 4 can be visually recognized.

  The rice mill main body 2 is provided with a control circuit 37. The control circuit 37 is electrically connected with a rice milling start operation unit 38, a rice amount setting operation unit 39, a milling degree setting operation unit 40, a rotation speed sensor 41, and the electric motor 16. The rice amount setting operation unit 39 and the whiteness setting operation unit 40 constitute the operation unit 10. P is an AC power source.

  Next, the operation of the above configuration will be described. In the following description, a case where rice is polished from brown rice will be described. First, the user attaches the rice milling body 5 to the engagement shaft portion 30 of the secondary driven shaft 29 of the rice milling container 4, and then stores a predetermined amount of brown rice in the rice milling container 4. Further, the rice bran receiver 3 is attached to the storage recess 7 </ b> B of the rice miller body 2. At this time, the upper side of the primary connection portion 21 constituting the coupling 32 is exposed from the through hole 3B, and the outer peripheral side is covered by the cylindrical portion 3C. Then, the rice mill container 4 is attached to the inside of the rice bran receptor 3. At this time, the secondary connection portion 31 constituting the coupling 32 is inserted into the cylindrical portion 3 </ b> C and engaged with the primary connection portion 21. Further, the rice mill container 4 is positioned with respect to the rice bran receptacle 3 by mounting the cylindrical part 25C so as to cover the upper outer side of the cylindrical part 3C. Further, the upper opening of the storage recess 7 </ b> B is closed by the lid 6. Then, a cord (not shown) is pulled out from the cord reel 11 and the plug of this cord is connected to the AC power source P. Next, the rice amount setting operation unit 39 is operated based on the amount of brown rice accommodated in the rice milling container 4. Further, the milling degree setting operation unit 40 is operated based on the target milling degree of the brown rice accommodated in the milled rice container 4. As a result, parameters for the control circuit 37 to control the electric motor 16 are set. Further, when the rice milling start operation unit 38 is operated, the control circuit 37 drives the electric motor 16. The driving force of the electric motor 16 rotates the milled rice body 5 from the small pulley 18 through the driving belt 20, the large pulley 19, the first driven shaft 17, the coupling 32, and the secondary driven shaft 29. The milled rice body 5 is rotated at a predetermined reduction ratio with respect to the rotational speed of the electric motor 16 according to the radius ratio of the small pulley 18 and the large pulley 19.

  Then, by rotating the polished rice body 5, the brown rice in the polished rice container 4 is agitated and rotated with the rotation of the polished rice body 5. At this time, the brown rice in the rice mill container 4 is polished by the rice grains rubbing each other or by the rice grains rubbing the rice mill container 4. Note that the rice grains move in the milled rice vessel 4 so as to smoothly get over the columnar rod-shaped body 35 or pass through the columnar rod-shaped body 35 smoothly. For this reason, since the rice grains do not move more intensely than necessary in the rice milling container 4, the temperature rise of the rice due to friction and collision can be kept low. And if the temperature rise of the rice at the time of rice polishing is suppressed, the reduction | decrease amount of the water | moisture content of rice can be suppressed low, and generation | occurrence | production of a broken rice can be suppressed low. Moreover, if the temperature rise of the rice at the time of rice polishing is suppressed, the oxidation of the rice by heat will also be suppressed. Therefore, deterioration of the taste of rice can be suppressed. In addition, since the rod-shaped body 35 has a relatively thick columnar shape and the front end in the rotation direction is dull, when the rod-shaped body 35 collides with the rice grain, the impact is not concentrated on the local area of the rice grain. For this reason, generation | occurrence | production of a broken rice can be suppressed lower.

  The rice cake or the like scraped off from the rice is discharged together with the air flow from the mesh portion 24 of the rice milling container 4 and stored in the rice cake acceptor 3. Then, as described above, the cylindrical portion 25C covers the upper outer side of the cylindrical portion 3C, so that ridges and the like are prevented from entering the rice mill main body 2 from the through hole 7C.

  Rice is softer than the steel forming the mesh portion 24. However, when a large amount of rice is rubbed with the mesh body 24 for a long period of time, the mesh body 24 is worn. When the wear of the mesh body 24 proceeds, the mesh body 24 may be broken. However, since the disc portion 27 is provided inside the bottom of the mesh portion 24, the lower portion of the rod-like body 35 where the friction with the rice is the largest is less likely to be worn, so that the rice mill container 4 is less likely to be damaged. . In particular, since the outer edge of the outer peripheral portion 27A of the disc portion 27 extends to the outside of the locus drawn by the tip 35A of the rod-like body 35, the friction between the mesh-like portion 24 and rice becomes the largest. The entire lower part can be made hard to wear. In addition, since the disk part 27 has no holes other than the holes corresponding to the bearing cylinder part 25A and has a smooth surface, friction between the disk part 27 and the rice can be reduced. As a result, the wear of the disk portion 27 itself can be minimized.

  In addition, since the hole is not formed in the said disc part 27, the rice cake etc. which were removed from the rice are not discharged | emitted below. However, since the outer edge of the outer peripheral portion 27A of the disc portion 27 is lower than the lower end 35B of the rod-like body 35, the rice cake removed from the rice is discharged along with the air flow from the mesh portion 24 in the horizontal direction in which centrifugal force acts. Is done. This discharge is not hindered by the disk portion 27. Further, since the friction between the disc portion 27 and the rice is small and the outer peripheral portion 27A of the disc portion 27 is smoothly curved upward along the curved portion 24C, it is stirred by the rice milling body 5. After the rice moves vigorously toward the outer peripheral portion 27A by centrifugal force, the rice rises smoothly and vigorously upward along the outer peripheral portion 27A. Then, the rice that has risen vigorously rises along the side peripheral portion 24A of the mesh-like portion 24, and is rubbed against the side peripheral portion 24A, whereby wrinkles and the like are removed. As described above, the rice rises vigorously along the side peripheral portion 24A, so that the rice reaches a high position along the side peripheral portion 24A. For this reason, the area which rice rubs in the said side periphery 24A can be enlarged. Accordingly, a reduction in the efficiency of rice milling due to the fact that the rice does not rub against the bottom 24B of the mesh portion 24 can be suppressed.

  The higher the position of the rice along the side circumferential portion 24A, the lower the revolution speed of the rice due to friction with the mesh portion 24. Accordingly, the higher the position along the side peripheral portion 24A, the lower the centrifugal force acting on the rice. For this reason, the airflow discharged from the rice milling container 4 by centrifugal force becomes weaker upward along the side peripheral portion 24A, and flows into the rice milling container 4 from a certain height upward. Above this height, the rice moves toward the center of the rice milling container 4. In other words, below this height, the rice moves along the side periphery 24A. Accordingly, the rice cake or the like riding on the airflow tries to flow into the rice mill container 4 from the rice cake acceptor 3 through the upper part of the side peripheral portion 24A of the mesh portion 24. At this time, wrinkles or the like adhere to the upper outer surface of the side peripheral portion 24 </ b> A of the mesh body 24.

  The control of the electric motor 16 by the control circuit 37 will be described in detail. The process of controlling the electric motor 16 by the control circuit 37 includes a starting process and a rotation control process following the starting process. The starting step is a step of gradually increasing the electric power supplied to the electric motor 16. This starting process is executed in order to reduce the load of the electric motor 16 that rotates the polished rice body 5 against the resistance of the rice contained in the polished rice container 4. In this starting process, constant control is performed regardless of the amount of milled rice and the degree of milling, and the signal from the rotation speed sensor 41 is not referred to. The rotation control step is a step of controlling the rotation speed of the milled rice body 5 by adjusting the power supplied to the electric motor 16 based on the signal from the rotation speed sensor 41.

  The start-up process includes a first process, a second process that is performed following the first process, and a third process that is performed following the second process. In the first step, the supplied power is gradually increased. In the second step, the supply power is increased more rapidly than in the first step. In the third step, the supplied power is increased more slowly than in the second step. In the present embodiment, as shown in FIG. 4, the electric power supplied to the electric motor 16 is increased by increasing the duty ratio by PWM control. In the first step, the duty ratio is increased by 1% every about 0.1 second from 20% to 24% in the first step. In the second step, the duty ratio is increased from 24% to 51% by about 3% every about 0.1 second. Further, in the third step, the duty ratio is increased by 1.5% every 0.1 seconds from 51% to 73.5%.

  In the first step, since the rate of increase in the duty ratio is kept low, the rotational speed of the rice milling body 5 also increases gradually. At first glance, it seems that the revolving speed of the brown rice in the rice milling container 4 increases gradually. However, in the rice mill 1 using the milled rice body 5 having the cylindrical rod-like body 35 as in the present embodiment, when the rotational speed of the milled rice body 5 is rapidly increased, only the milled rice body 5 rotates. As a result, brown rice hardly revolves, and it becomes almost empty. This is because the rod-shaped body 35 smoothly passes through the rice, so that the brown rice is difficult to rotate with the polished rice body 5 and the revolution speed of the brown rice is difficult to increase. When the rotational speed of the rice milling body 5 is gradually increased as in the present embodiment, the brown rice is easily brought along with the rice milling body 5, and the revolution speed of the brown rice can be gradually increased. As a result, the revolution speed of brown rice can be increased faster than when the revolution speed of the milled rice 5 is rapidly increased.

  Since brown rice starts to rotate in the first step, it becomes easy to move. Therefore, if the duty ratio is rapidly increased in the second step, the revolution speed of the brown rice also increases rapidly. In the second step, when the revolution speed of the brown rice increases, the vibration frequency of the rice mill container 4 generated by rubbing the brown rice with the mesh body 24 gradually increases. When the brown rice reaches a predetermined speed band V, the frequency of the rice milling container 4 overlaps with the resonance frequency of the rice milling machine body 2. As a result, the rice mill main body 2 vibrates greatly. The resonance frequency varies depending on the structure of the rice mill main body 2. However, as described above, in the second step, the supplied power is rapidly increased, and the rotational speed of the polished rice body 5 and the revolution speed of the brown rice are rapidly increased. It can be raised in a short time. Thereby, the time zone in which the rice mill main body 2 resonates can be shortened, and the resonance can be quickly converged.

  In the second step, the time zone during which the brown rice revolves in the speed zone V varies depending on the amount of brown rice in the rice mill container 4. When the amount of brown rice stored in the rice milling container 4 is small, the speed of brown rice rises relatively quickly, so that it rises to the speed zone V in an early time zone. On the other hand, when the amount of brown rice stored in the rice mill container 4 is large, the speed of brown rice rises relatively slowly, so that it rises to the speed zone V in a slow time zone. However, the time zone of the second step is the time zone T1 during which brown rice is in the speed zone V when browning rice with the minimum amount of polished rice, and the time during which brown rice is in the speed zone V when polishing rice with the maximum amount of polished rice It is set to include the band T2. Therefore, the resonance phenomenon of the rice mill main body 2 always occurs during the second step. The resonance phenomenon that occurs during the second step converges quickly as described above.

  And in a 3rd process, it can prevent that the rotational speed of the said polished rice body 5 and the revolution speed of brown rice at the time of completion | finish of a starting process become high too much by lowering the raise rate of a duty ratio again. Thus, generation | occurrence | production of a broken rice can be suppressed by not making the rotational speed of the said polished rice body 5 and the revolution speed of brown rice too high. In addition, when the amount of brown rice stored in the rice milling container 4 is small, if the revolution speed of the brown rice at the end of the starting process becomes too high, when the transition from the starting process to the rotation control process occurs, Brown rice does not move smoothly. This is because when the amount of polished rice is small, the rotational speed of the milled rice body 5 set in the rotation control process following the start process is low, so the rotational speed of the polished rice body 5 is greatly reduced. However, by reducing the rate of increase in the duty ratio in the third step, the brown rice can be smoothly revolved in the rice milling container 4 so as to be smoothly connected from the starting step to the rotation control step.

  In the rotation control step, the control circuit 37 controls the power supplied to the electric motor 16 based on the signal from the rotation speed sensor 41 that detects the rotation speed of the rice milling body 5. To control the rotation speed. When shifting from the starting process to the rotation control process, the rotational speed of the milled rice body 5 may be increased or decreased depending on the amount of brown rice in the milled rice container 4 and the set milling degree.

Several examples of the relationship between the rotational speed of the milled rice body 5 and time in the rotation control step will be described. In the present embodiment, the minimum amount of polished rice is 1 go (about 0.18 L). The maximum amount of polished rice is 5 go (about 0.90L).

  In the initial stage of the rotation control process, the rice is in the state of brown rice, and the surface is not smooth, so the friction between the rice revolved by the milled rice body 5 and the mesh portion 24 is large. Accordingly, when the revolving rice collides with the mesh portion 24, the speed of the rice is greatly reduced. This means that the impact applied to the rice is relatively large in the early stage of the rotation control process. However, as described above, by suppressing the rotational speed of the rice milling body 5 at the initial stage of the rotation control process, the revolution speed of the rice can be suppressed low. As a result, the impact applied to the rice when the rice collides with the mesh portion 24 can be reduced. Accordingly, generation of broken rice can be suppressed.

  As the rice rubs against the mesh portion 24 or the rice grains rub against each other, wrinkles and the like on the surface of the rice are gradually scraped off. As a result, the rice surface gradually becomes smoother. Then, when the surface of the rice is gradually smoothed in this way, the friction between the rice and the mesh portion 24 is gradually reduced. As a result, the speed reduction of the rice when the rice collides with the mesh portion 24 is gradually reduced. Therefore, the impact received when the rice collides with the mesh portion 24 is gradually reduced. For this reason, with the progress of the rotation control process, there is room for increasing the rotational speed of the rice milling body 5. That is, even if the rotational speed of the milled rice body 5 is increased with the progress of the rotation control process, the impact that the rice grains receive from the mesh portion 24 does not become excessive. Therefore, the rice milling time can be shortened while suppressing the occurrence of broken rice by increasing the rotational speed of the rice milling body 5 as the rotation control process proceeds.

  And the said control circuit 37 performs the completion | finish process following a rotation control process irrespective of the degree of whitening. In addition, this completion | finish process is performed when the amount of polished rice is 1 go-3 go (about 0.54L). In this end step, as shown in FIG. 11, electric power is supplied to the electric motor 16 for one second at a duty ratio of 100%. During this time, the rotational speed of the rice milling body 5 is not controlled. Actually, the rotational speed of the milled rice 5 is increased to about 3000 rpm in the end step. At this time, the rotational speed of the milled rice body 5 and the revolution speed of the rice are higher than the rotational speed of the polished rice body 5 and the revolution speed of the rice in the rotation control step. For this reason, while changing the airflow which passes the mesh part 24 of the said rice milling container 4, the vibration accompanying the revolution of rice increases. More specifically, the centrifugal force received by the rice increases as the rotational speed of the rice milling body 5 and the revolution speed of the rice increase. Then, when the milled rice body 5 rotates at a certain rotational speed or higher, the rice rises up to its upper end while revolving along the side peripheral portion 24A of the mesh portion 24. In this state, the airflow flows out from the rice milling container 4 to the outside of the rice milling container 4 in the entire side peripheral portion 24A. At this time, the rice is rubbed with the entire mesh portion 24, the entire mesh portion 24 vibrates and vibration of the mesh portion 24 increases, and the rice cake is easily separated from the mesh portion 24, The kite is pushed outward by the air current. As a result, the rice cake adhering to the outer surface of the mesh portion 24 of the rice milling container 4 is removed from the rice milling container 4 and falls into the rice bran receptacle 3. For this reason, when the rice milling container 4 is taken out from the rice milling machine main body 2 after the completion of the rice milling, it is possible to prevent the problem that the rice cake attached to the mesh portion 24 falls to the floor or the like. In addition, when the amount of polished rice is 4 go (about 0.72 L) or more, the rice rises to the upper end portion of the side peripheral portion 24A of the mesh portion 24 during the rotation control process, so that the entire mesh portion 24 vibrates. Since wrinkles are unlikely to adhere to the mesh portion 24, there is no need to execute an end step.

Note that the time of the end process may be in a range that satisfies all of the following conditions.
(1) The time is short enough not to substantially affect the degree of whitening. If the time of the end process is too long, coupled with an increase in the rotational speed of the milled rice body 5, more cocoons are removed.
(2) The time is short enough to keep the broken rice generation rate below the reference value. If the time for the end process is too long, the rate of broken rice will increase due to the increased rotational speed of the milled rice 5.
(3) The time is long enough to remove all wrinkles adhering to the mesh portion 24. This time is at least equal to or longer than the time during which the milled rice body 5 can make one rotation after the electric power having a duty ratio of 100% is supplied to the electric motor 16. In this case, the rice revolves at least once along the inner periphery of the mesh portion 24 at a high speed as a whole. At this time, the rice rises to a high position along the mesh portion 24 of the rice milling container 4, so that vibration can be generated in a wide range of the mesh portion 24. Furthermore, the time of the end process is longer than the time that the rice can reach the height H2 of the upper end portion of the side peripheral portion 24A from the height H1 along the side peripheral portion 24A at the end of the rotation control step. It is desirable to be. That is, the time of the end process is a time sufficient to reach the state of FIG. 13 by raising the rice whose revolution speed has been increased from the state of FIG. Is desirable.

  For example, in the present embodiment, when the number of rotations of the milled rice 5 in the rotation control process is minimized (three-milling / one go), the milled rice 5 rotates about 1250 in the rotation control process. When it is assumed that the rotational speed in the finishing process of the milled rice 5 is increased to 3000 rpm, the polished rice 5 is rotated 50 times in 1 second of the finishing process. That is, the ratio of the number of rotations of the rice milling body 5 in the end step to the number of rotations of the rice milling body 5 in the rotation control process is about 4%. Even if the number of rotations of the milled rice 5 is increased by about 4%, the milling degree is not substantially affected. Further, even if the number of rotations of the milled rice 5 is increased by about 4%, it does not substantially affect the broken rice generation rate. Furthermore, if the end step is about 1 second, the rice rises to the height H2 of the upper end portion along the side peripheral portion 24A of the mesh portion 24 in this 1 second. As a result, the entire mesh portion 24 vibrates due to friction with the rice and the vibration of the mesh portion 24 increases, so that the soot and the like attached to the mesh portion 24 of the milled rice container 4 can be sufficiently removed. In the present embodiment, when the number of rotations of the milled rice 5 in the rotation control process is maximized (upper white rice / 3), the milled rice 5 rotates about 8480 in the rotation control process. In this case, the ratio of the number of rotations of the rice milling body 5 in the end step to the number of rotations of the rice milling body 5 in the rotation control step is about 0.6%. Therefore, the influence is further reduced as compared with the case where the number of rotations of the rice milling body 5 is minimized.

  On the other hand, the duty ratio in the ending process is such that the rice is rotated along the side peripheral portion 24A of the mesh portion 24 while rotating the rice along the side peripheral portion 24A of the mesh portion 24, and the height H2 of the upper end portion thereof. As long as the milled rice body 5 can be rotated at a rotational speed that can be increased to a high level, it is sufficient. For example, in this embodiment, the duty ratio of the power supplied to the electric motor 16 is 100%. If the electric power of this duty ratio is supplied to the electric motor 16 to rotate the polished rice body 5, the rice reaches the height H2 of the upper end of the side peripheral portion 24A even if the amount of polished rice is minimum.

  As described above, in the present invention, the rice mill container 4 provided with the mesh-like portion 24 in which the rice grains do not pass and the holes for passing the rice cake are provided, and the rice in the rice mill container 4 is rotated in the rice mill container 4. A rice mill 1 having a rice milling body 5 to be stirred, an electric motor 16 that rotates the rice milling body 5, and a control circuit 37 that drives and controls the electric motor 16 by PWM. The control circuit 37 adjusts the duty ratio. And performing a rotation control step for controlling the rotational speed of the milled rice body 5 and executing an end step of rotating the electric motor 16 for a short time at a duty ratio higher than the duty ratio in the rotation control step. It is possible to change the airflow flowing through the inside and outside of the rice milling container 4 and increase the vibration so as to remove the soot adhering to the outer surface of the rice milling container 4.

  In addition, the present invention sets the time for the end step to be equal to or longer than the time for one revolution of the milled rice, so that the rice also revolves around the milled rice container 4 at a high speed for one or more revolutions. Since it can be raised to a high position and vibration can be generated in a wide range of the rice milling container 4, soot and the like can be reliably removed from the rice milling container 4.

  In addition, this invention is not limited to the above embodiment, A various deformation | transformation implementation is possible within the range of the summary of invention. For example, in the above embodiment, the end step is set to 1 second at a duty ratio of 100%. However, if the duty ratio is sufficiently higher than the duty ratio in the rotation control step and satisfies the above-described conditions, the duty ratio is set. And time is arbitrary.

DESCRIPTION OF SYMBOLS 1 Rice milling machine 4 Rice milling container 5 Rice milling body 16 Electric motor 24 Mesh part 37 Control circuit

Claims (4)

A rice milling container formed with a hole that does not pass rice grains and passes rice bran, a rice mill that rotates in the rice milling container and stirs the rice in the rice milling container, an electric motor that rotates the rice milling body, and this motor In a rice mill having a control circuit for drive control by PWM,
The control circuit executes a rotation control step of adjusting the duty ratio to control the rotational speed of the milled rice, and an end step of rotating the electric motor for a short time at a duty ratio higher than the duty ratio in the rotation control step A rice mill characterized by performing.   2. The rice milling apparatus according to claim 1, wherein the time for the end step is set to be equal to or longer than a time for one rotation of the milled rice. A rice milling container formed with a hole that does not pass rice grains and passes rice bran, a rice mill that rotates in the rice milling container and stirs the rice in the rice milling container, an electric motor that rotates the rice milling body, and this motor In a control method of a rice mill having a control circuit for drive control by PWM,
In the rotation control step, the control circuit controls the rotational speed of the milled rice by adjusting the duty ratio of the electric power supplied to the electric motor, and in the end step following the rotation control step, in the rotation control step A method for controlling a rice mill, comprising: rotating the electric motor for a short time at a duty ratio higher than a duty ratio.   4. The method for controlling a rice mill according to claim 3, wherein the end step is executed for a time longer than a time for which the milled rice body makes one revolution.

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