JP6271784B2 - Stepping motor and electric valve using the same - Google Patents

Description

  The present invention relates to a stepping motor and an electric valve using the stepping motor.

  Conventionally, in a motor operated valve using a stepping motor, for example, by inputting a driving pulse signal exceeding the maximum number of steps necessary for closing the motor operated valve to the stepping motor, a reliable base point positioning of the stepping motor (also called initialization) is performed. Say). An electromagnetic coil device for a stepping motor in such a motor-operated valve is disclosed in, for example, Patent Document 1, and in this prior art, an exciting coil having a pair of magnetic pole plates (magnetic pole teeth) provided from the upper and lower sides thereof is vertically moved. Are provided in two layers.

  By the way, if the rotor constituting the stepping motor is stopped at the base position by a stopper or the like and then the drive pulse signal is continuously input to the stepping motor, abnormal noise or vibration is generated or the durability of the motor-operated valve is reduced. Problems are known to arise.

  For such a problem, Patent Document 2 discloses a technique for detecting that the rotor has come into contact with the stopper when the base point of the stepping motor is positioned, and stopping the base point positioning pulse for energizing the drive coil. .

  The motor-driven valve driving device disclosed in Patent Document 2 outputs a base point positioning pulse to the stator drive coil so that the rotor of the stepping motor returns to the base point position when the motor valve base point is positioned, and magnetic detection The magnetic detection signal from the means is input, the change pattern corresponding to the timing difference between when the magnetic detection signal transitions from the high level to the low level or from the low level to the high level and per stopper is recognized. In this process, the contact of the rotor with the stopper is detected to stop the output of the reference position pulse.

JP-A-2005-287152 Japanese Patent No. 4028291

  By the way, as described above, after the rotor comes into contact with the stopper at the base position and stops, if the drive pulse signal is continuously input to the stepping motor, the rotor is attracted to the opposite phase (magnetic pole) and reversed in a certain step. If the drive pulse signal is continuously input to the stepping motor, the rotor is reversed again and comes into contact with the stopper again.

  For example, when the magnetic pole pattern of the coil is repeated every 8 steps according to a predetermined excitation sequence to the stator coil, as shown in FIG. 8, in steps 7 to 4, the rotor is predetermined for each input of the drive pulse signal. The rotor on the rotor side is driven to rotate at an angle, and the stopper on the fixed side provided at the base point position of the rotor approaches. In step 3, the rotor-side stopper and the stationary-side stopper come into contact with each other, and the rotor stops at the base position. Thereafter, from step 2 to step 0, even if a drive pulse signal is input, the rotor is prevented from being rotationally driven, and the rotor continues to stop at the base position (stepping). In FIG. 8, the mark drawn with an imaginary line (two-dot chain line) indicates that the rotor-side stopper continues to rotate when it is assumed that there is no fixed-side stopper.

  However, when the excitation of the stator coil is shifted from step 0 to step 7, the rotor is attracted to the opposite phase (magnetic pole) and reversed, and the rotor-side stopper is separated from the fixed-side stopper (8-step reversal). ). That is, in step 2 to step 0, the rotor-side stopper that has come into contact with the fixed-side stopper is drawn to the position indicated by the two-dot chain line, but when the process proceeds from step 0 to step 7 again, the rotor is drawn to the subsequent phase. The rotor is reversed.

  In the motor-driven valve driving device disclosed in Patent Document 2, such contact / reversal operation is converted into a digital signal using an alternating Hall IC or the like, and the rotor is stopped by comparing with a normal driving waveform. Detected.

  However, the abutting / reversing operation described above is a periodic motion, and depending on the detection position, the drive waveform associated with the abutting / reversing operation may be synchronized with the normal driving waveform, that is, the driving waveform associated with the abutting / reversing operation. There is a possibility that the normal drive waveform does not change much. For this reason, in the above-described method of positioning the base point of the rotor using the contact / reverse operation, there may be a problem that the stop of the rotor due to contact with the stopper cannot be reliably detected.

  The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a stepping that can precisely and reliably stop the rotor with respect to the stopper, that is, locate the base point of the rotor with a simple configuration. The object is to provide a motor and an electric valve using the motor.

  In order to solve the above-described problem, a stepping motor according to the present invention includes a stator and a rotor that is rotationally driven by the stator, and includes a detection rotor that detects a rotational position of the rotor, and the detection rotor Is rotatably arranged coaxially with the rotor and is rotationally driven by the rotor via a rotational drive mechanism between the rotor and the detection rotor, and the rotational drive mechanism has a predetermined length in the rotational direction. A drive play of a length or angle, and when the rotor is reversed, transmission of a rotational drive force from the rotor to the detection rotor is suppressed within a range of the length or angle of the drive play. Yes.

  In addition, a stepping motor according to the present invention includes a stator and a rotor that is rotationally driven by the stator, and has a detection rotor that detects a rotational position of the rotor, and the detection rotor is coaxial with the rotor. The rotor is rotatably arranged and is driven to rotate by the rotor via a rotation drive mechanism between the rotor and the detection rotor, and the rotation drive mechanism is provided in one of the rotor and the detection rotor. A plurality of protrusions arranged at predetermined length intervals or angular intervals in the rotation direction, and separate protrusions provided between the plurality of protrusions and provided on either one of the rotor and the detection rotor The separate protrusion has a drive play that is relatively movable between the plurality of protrusions.

  In addition, a stepping motor according to the present invention includes a stator and a rotor that is rotationally driven by the stator, and has a detection rotor that detects a rotational position of the rotor, and the detection rotor is coaxial with the rotor. The rotor is rotatably arranged and is driven to rotate by the rotor via a rotation drive mechanism between the rotor and the detection rotor, and the rotation drive mechanism is provided in one of the rotor and the detection rotor. A driving play recess having a predetermined length interval or angular interval in the rotation direction, and a protrusion provided on the other of the rotor and the detection rotor and loosely fitted in the drive play recess, The protrusion has a drive play that is relatively movable inside the drive play recess.

  In a preferred embodiment, the stepping motor has a rotation stop mechanism that prevents the rotation of the rotor, and the length or angle of the drive play of the rotation drive mechanism is such that the rotation of the rotor is blocked by the rotation stop mechanism. More than the reversal length or reversal angle of the rotor at the time.

  In a preferred embodiment, the detection rotor is provided with an urging force that suppresses the rotation of the detection rotor, and preferably the urging force is generated by a magnetic body provided outside the detection rotor. Is done.

  The motor-operated valve according to the present invention includes the stepping motor, and has a valve body having a valve chamber and a valve opening that opens to the valve chamber, and is arranged to be movable up and down in the valve chamber so as to open and close the valve port. A valve body, and a conversion mechanism that converts the rotary motion of the rotor of the stepping motor into a lifting motion of the valve body, and the stepping motor rotates the rotor by the stator, and the conversion mechanism When the valve body is moved up and down and the valve body reaches a predetermined position, the rotation of the rotor is prevented by a rotation stop mechanism.

  In a preferred embodiment, the predetermined position is a position where the valve body closes the valve port or a position where the valve body fully opens the valve port.

  In a preferred embodiment, a can is fixed to the valve body, and the rotor and the detection rotor are disposed inside the can.

  According to the stepping motor of the present invention and the electric valve using the stepping motor, the detection rotor for detecting the rotational position of the rotor is rotatably arranged on the same axis as the rotation axis of the rotor and is rotationally driven by the rotor. The rotation drive mechanism between the rotor and the detection rotor has a drive play of a predetermined length or angle in the rotation direction, so that the drive play length or angle is within the range when the rotor is reversed. Thus, transmission of the rotational driving force from the rotor to the detection rotor is suppressed, so even if the rotor abuts against the stopper and vibrates, this vibration is not transmitted to the detection rotor. Therefore, by detecting a signal based on this detection rotor, for example, it can be surely detected that the valve body of the motor-operated valve has reached a predetermined position, and the base point positioning of the rotor can be precisely performed. In addition, since the length or angle of the drive play of the rotation drive mechanism is equal to or greater than the reversal length or reversal angle of the rotor, the transmission of the rotational drive force from the rotor to the detection rotor when the rotor is reversed is further reliably prevented. Therefore, the positioning of the base point of the rotor can be performed more precisely. Further, since the biasing force that suppresses the rotation of the detection rotor is applied to the detection rotor, the signal based on the detection rotor when the rotor is reversed is stabilized, so detection of the stopper contact state of the rotor, that is, The position of the base point of the rotor can be determined more precisely.

The longitudinal section showing the basic composition of the embodiment of the electric valve concerning the present invention. The schematic diagram which shows typically the basic composition of the stepping motor applied to the motor operated valve shown in FIG. AA arrow sectional drawing of FIG. The figure which demonstrated typically the drive of the rotor of the stepping motor shown in FIG. The figure explaining the drive of the rotor of the stepping motor shown in FIG. 2, and the output signal of Hall IC. The schematic diagram which shows typically the basic composition of other embodiment of the stepping motor applied to the motor operated valve shown in FIG. BB arrow sectional drawing of FIG. The figure which illustrates typically the drive of the rotor of the conventional stepping motor.

  Embodiments of a stepping motor and a motor-operated valve using the stepping motor according to the present invention will be described below with reference to the drawings.

  FIG. 1 shows a basic configuration of an embodiment of a motor-operated valve according to the present invention, and shows its closed state. The illustrated motor operated valve 1 is used in, for example, a heat pump air conditioning system. 2 schematically shows a basic configuration of a stepping motor applied to the motor-operated valve shown in FIG. 1, and FIG. 3 is a cross-sectional view taken along line AA in FIG.

  The motor-operated valve 1 shown in FIG. 1 mainly includes a valve body 20 having a valve chamber 21 and a valve port 22a that opens to the valve chamber 21, and a shaft that can be moved up and down in the valve chamber 21 to open and close the valve port 22a. And a stepping motor 50 that raises and lowers the valve body 25.

  In the valve chamber 21 of the valve body 20, a valve port 22a with a valve seat 22 that opens to the valve chamber 21 is formed in the lower portion thereof, and the first inlet / outlet 11 is opened in a side portion thereof, and a lower portion of the valve port 22a. The second inlet / outlet 12 communicating with the valve port 22a is opened.

  A lower end portion of a cylindrical can 58 having a ceiling portion is fixed to an upper opening portion of the valve main body 20, and a lower end portion of the cylindrical guide bush 26 is press-fitted to an upper inner peripheral portion of the valve main body 20. The valve body 25 is slidably fitted inside the guide bush 26. A male screw 28 is formed on the outer periphery of the upper reduced diameter portion 26 b of the guide bush 26, and a cylindrical valve body holder 32 is fitted around the outer periphery of the guide bush 26. A female screw 38 is formed on the inner periphery of the valve body holder 32. The male screw 28 of the guide bush 26 and the female screw 38 of the valve element holder 32 are screwed together.

  Further, the upper reduced diameter portion 25b of the valve body 25 is fixed to the cylindrical rotating shaft (support shaft) 56 by press fitting or the like while being slidably inserted into the upper portion (ceiling portion) of the valve body holder 32. ing. Further, there is a compression coil between the outer periphery of the upper reduced diameter portion 25b of the valve body 25 and between the ceiling portion of the valve body holder 32 and the step portion between the lower large diameter portion 25a of the valve body 25 and the upper reduced diameter portion 25b. A spring 34 is disposed, and the valve body 25 is urged downward (in the valve closing direction) by the coil spring 34.

  On the other hand, the stepping motor 50 includes a yoke 51, a bobbin 52, a stator coil 53, a resin mold cover 54, and the like. The stepping motor 50 rotates with respect to the can 58 inside the can 58 and the stator 55 that is externally fixed to the can 58. And a freely arranged rotor 57. The rotor 57 is formed of, for example, a magnet in which a magnetic material is mixed with a resin and the N pole and the S pole are magnetized at a predetermined interval. A support ring 36 is integrally fixed to the upper end portion of the rotor 57, and the upper protrusion of the valve body holder 32 is caulked and fixed to the support ring 36. Therefore, the rotor 57, the support ring 36, and the valve body holder 32 are integrally connected, and the valve body 25 to which the rotary shaft 56 is fixed is slidably supported by the valve body holder 32 via the coil spring 34. Yes. Therefore, when the rotor 57 rotates and moves up and down, the valve body 25 also moves up and down.

  In addition, it is mounted on a projecting support portion 56 a formed on the rotation shaft 56 of the rotor 57 above the rotor 57 and inside the can 58, and is relatively rotatable with respect to the rotation shaft 56 of the rotor 57. In addition, a detection rotor 47 that is disposed coaxially with the rotational axis L of the rotor 57 and that is rotationally driven by the rotational driving force of the rotor 57 is disposed. The detection rotor 47 has a diameter that is the same as or different from the diameter of the rotor 57, and is magnetized in the same pattern as the rotor 57 (a pattern in which the angular interval between the N pole and the S pole is the same as that of the rotor 57). ing. And the detection rotor 47 and the rotor 57 are arrange | positioned so that each magnetic force may not influence each other. The angular interval between the N pole and the S pole of the magnetization pattern formed on the outer periphery of the detection rotor 47 may be different from that of the rotor 57.

  Two protrusions 57b and 57c are provided on the upper surface of the rotor 57 with a predetermined length interval (or angular interval) R1 in the rotational direction of the rotor 57. Is provided with a rod-like protrusion 47a disposed between the two protrusions 57b and 57c of the rotor 57 (see FIG. 2). As described above, the tip end of the rod-shaped protrusion 47a is disposed between the two protrusions 57b and 57c of the rotor 57, so that the detection rotor 47 has a predetermined length interval (or angular interval) R1 in the rotation direction of the rotor 57. Is relatively rotatable with respect to the rotor 57 (see FIG. 3). As described above with reference to FIG. 8, the distance R1 is a length (reversed length) or angle at which the rotor is reversed by the subsequent phase (magnetic pole) after the rotor-side stopper contacts the fixed-side stopper. It is set so that it can be rotated more than (reversal angle).

  The upper end of the rotating shaft 56 is inserted into and supported by a hole formed in the center of a support member 48 that is disposed in contact with the can 58.

  Further, a magnetic body 46 is disposed outside the detection rotor 47, and an urging force (also referred to as detent torque) that suppresses the rotation of the detection rotor 47 by a magnetic field formed around the detection rotor 47 by the magnetic body 46. Has been granted. Further, a Hall IC 45 that detects a change in magnetism by the detection rotor 47 is disposed outside the detection rotor 47, and the rotational position of the rotor 57 is detected based on an output signal detected by the Hall IC 45.

  Further, a stopper (fixed side stopper) 27 is fixed to the outside of the guide bush 26, and a stopper 37 is fixed to the outside of the valve body holder 32. When the valve body 25 reaches a predetermined position, for example, the valve body 25 When the rotor 57 is rotated down to a position where the valve body 24 at the lower end closes the valve port 22a, the rotor 57 is prevented from further rotating. That is, in the present embodiment, a rotation stop mechanism 59 that prevents the rotation of the rotor 57 is configured by the stopper 27 of the guide bush 26 and the stopper 37 of the valve body holder 32.

  In the motor-operated valve 1 described above, when a driving pulse signal is supplied to the stator 55 in the first mode (driving mode in the valve closing direction), the rotor 57 and the valve body holder with respect to the guide bush 26 fixed to the valve body 20. 32, the rotating shaft 56 and the like rotate in one direction (for example, clockwise when viewed from above in FIG. 1), and the valve element holder 32 is moved by screw feed of the male screw 28 of the guide bush 26 and the female screw 38 of the valve element holder 32. The valve body part 24 of the valve body 25 is pressed against the valve port 22a via the compression coil spring 34, and the valve port 22a is closed. A conversion mechanism for converting the rotational movement of the rotor 57 of the stepping motor 50 into the vertical movement of the valve body is constituted by the male screw 28 of the guide bush 26 and the female screw 38 of the valve body holder 32. At this time, the protrusion 47a on the lower surface of the detection rotor 47 and the protrusion 57c on the upper surface of the rotor 57 abut, and the driving force is transmitted from the rotor 57 to the detection rotor 47 via the protrusions 57c and 47a. Rotate in one direction following. Note that the detection rotor 47 descends according to the rotation of the rotor 57 so that the distance between the detection rotor 47 and the rotor 57 is maintained substantially constant.

  When the valve port 22a is closed, the stopper 37 of the valve body holder 32 comes into contact with the stopper 27 of the guide bush 26, and even if a drive pulse signal is supplied to the stator 55, the lowering of the valve body holder 32 is forcibly prevented. In a state where the projection 47a of the detection rotor 47 and the projection 57c of the rotor 57 are in contact with each other, the rotation of the rotor 57 and the detection rotor 47 is prevented.

  When the drive pulse signal is further supplied to the stator 55, the rotor 57 is attracted to the opposite phase (magnetic pole) in a certain step and reversed, and for example, the stopper 27 of the guide bush 26 and the stopper 37 of the valve body holder 32 are separated. . On the other hand, the detection rotor 47 is rotatable relative to the rotor 57. As described above, the interval R1 between the protrusions 57b and 57c of the rotor 57 in the rotational direction is a rod-like shape of the detection rotor 47 on the inner side. The protrusion 47a is set so that it can rotate more than the reverse length (or reverse angle) of the rotor 57 (see FIG. 3). Therefore, even if the rotor 57 is attracted to the opposite phase and reversed, the protrusion 47a of the detection rotor 47 does not come into contact with the protrusion 57b of the rotor 57, and no driving force is transmitted from the rotor 57 to the detection rotor 47. The detection rotor 47 to which the urging force is applied by the body 46 does not rotate. That is, the detection rotor 47 once stopped at the position where the valve body 25 closes the valve port 22a continues to stop at that position even if the rotor 57 is reversed. By detecting the magnetism generated by the detection rotor 47 using the Hall IC 45, it is reliably detected that the lowering of the valve body 25 has stopped and the valve port 22a has been closed (the position of the base point of the rotor 57 is determined). be able to.

  Further, if the energization to the stator 55 is stopped thereafter, the generation of vibration and noise due to the contact between the stopper 27 of the guide bush 26 and the stopper 37 of the valve body holder 32 can be suppressed.

  Further, since the magnetic body 46 is disposed outside the detection rotor 47, the detection rotor 47 can continue to stably stop at that position even if the rotor 57 is reversed due to the magnetic force between the detection rotor 47 and the magnetic body 46. it can.

  Note that a drive pulse signal is supplied to the stator 55 in the second mode (driving mode in the valve opening direction) from the valve closed state of the valve port 22a, and the rotor 57 is applied to the guide bush 26 fixed to the valve body 20. When the valve body holder 32, the rotary shaft 56, etc. are rotated in the other direction (for example, counterclockwise when viewed from above in FIG. 1), the screw thread feed of the male screw 28 of the guide bush 26 and the female screw 38 of the valve body holder 32 The valve body holder 32 is raised, the valve body portion 24 of the valve body 25 is separated from the valve port 22a, and the valve port 22a is opened. For example, the refrigerant passes through the valve port 22a. At that time, after the detection rotor 47 continues to stop for a certain step, the protrusion 47a on the lower surface of the detection rotor 47 and the protrusion 57b on the upper surface of the rotor 57 come into contact with each other, and then from the rotor 57 via the protrusions 57b and 47a. The driving force is transmitted to the detection rotor 47, and the detection rotor 47 follows the rotor 57 and rotates in the other direction.

  Next, with reference to FIG. 4, the driving of the detection rotor 47 and the rotor 57 when the rotor 57 and the like rotate in one direction (for example, clockwise when viewed from above in FIG. 1) will be described in more detail. . For example, as in the case of FIG. 8, when the magnetic pole pattern of the coil is repeated every 8 steps according to a predetermined excitation order to the stator coil, first, in step 7 shown in the upper diagram of FIG. As the rotor 57 rotates in one direction based on the drive pulse signal 55, the protrusion 57c provided on the upper surface of the rotor 57 and the protrusion 47a provided on the lower surface of the detection rotor 47 abut.

  Next, in step 7 to step 4, when a drive pulse signal is input, the driving force is transmitted from the rotor 57 to the detection rotor 47 via the protrusions 57 c and 47 a, and the detection rotor 47 is subjected to the urging force by the magnetic body 46. Against this, it is rotationally driven together with the rotor 57. Thereby, the stopper 37 (rotor 57 side stopper) of the valve body holder 32 approaches the stopper 27 (fixed side stopper) of the guide bush 26, and the protrusion 57 c of the rotor 57 and the protrusion 47 a of the detection rotor 47 are connected to the rotor 57. Approaches the position corresponding to the base point position. In step 3, when a drive pulse signal is input, the stopper 37 (rotor 57 side stopper) of the valve body holder 32 and the stopper 27 (fixed side stopper) of the guide bush 26 come into contact with each other, and the protrusion 57c of the rotor 57 The rotor 57 stops at the base position with the protrusion 47a of the detection rotor 47 in contact. Thereafter, in Step 2 to Step 0, even if a drive pulse signal is input, the rotation of the rotor 57 and the detection rotor 47 is blocked, and the rotor 57 continues to stop at the base point position (stepping).

  Next, when the drive pulse signal is input after the transition from Step 0 to Step 7, the rotor 57 is attracted to the opposite phase (magnetic pole) and reversed as shown in the lower diagram of FIG. The stopper 37 (rotor 57 side stopper) of the body holder 32 is separated from the stopper 27 (fixed side stopper) of the guide bush 26. On the other hand, the detection rotor 47 is rotatable relative to the rotor 57. As described above, the interval R1 between the protrusions 57b and 57c of the rotor 57 in the rotational direction is a rod-like shape of the detection rotor 47 on the inner side. The protrusion 47a is set so as to be able to rotate more than the reverse length (or reverse angle) of the rotor 57. Therefore, even if the rotor 57 is attracted to the opposite phase and reversed, the driving force is not transmitted from the rotor 57 to the detection rotor 47, and the detection rotor 47 continues to stop at the base point position of the rotor 57. The detection rotor 47 once stopped at the base point position of the rotor 57 continues to stop at the base point position of the rotor 57 even if the contact / reverse operation of the rotor 57 occurs repeatedly. By detecting the magnetism generated in the detection rotor 47 by using the Hall IC 45, even if the rotor 57 is reversed, it is reliably detected that the rotor 57 has reached a predetermined base position (the base position of the rotor 57 is determined). It can be carried out.

  Referring to FIG. 5, a stepping motor 50 having a stator in which a coil having a pair of magnetic pole teeth provided on the inside from the top and the bottom is provided in two layers is used as disclosed in Patent Document 1. When the rotor 57 or the like rotates in one direction (for example, clockwise when viewed from above in FIG. 1), the detection rotor 47 of the stepping motor 50 and the driving of the rotor 57 and the output signal of the Hall IC 45 are more concrete. Explained.

  First, as the rotor 57 rotates in one direction based on the drive pulse signal of the stator 55, the protrusion 57c provided on the upper surface of the rotor 57 and the protrusion 47a provided on the lower surface of the detection rotor 47 are brought into contact (in the drawing). , Circle 1). If the N pole and the S pole of the stator 55 are sequentially switched while the protrusion 57c of the rotor 57 and the protrusion 47a of the detection rotor 47 are in contact, the driving force is transmitted from the rotor 57 to the detection rotor 47 via the protrusions 57c and 47a. The rotor 57 made of a magnet rotates, the detection rotor 47 rotates together with the rotor 57, and an output signal having a rectangular waveform that changes from 0V to 5V, 5V to 0V, and 0V to 5V, for example, is detected by the Hall IC 45 (FIG. Medium, circle 1 to circle 10).

  In the next step, the stopper 37 (rotor 57 side stopper) of the valve body holder 32 and the stopper 27 (fixed side stopper) of the guide bush 26 contact each other, and the protrusion 57c of the rotor 57 and the protrusion 47a of the detection rotor 47 contact each other. In this state, rotation of the rotor 57 and the detection rotor 47 is prevented (circle 11 in the figure: corresponding to step 3 in FIG. 4). Thus, even if the N pole and S pole of the stator 55 are sequentially switched while the stopper 37 (rotor 57 side stopper) of the valve body holder 32 and the stopper 27 (fixed side stopper) of the guide bush 26 are in contact, the rotor 57 and the detection rotor 47 do not rotate, the rotor 57 and the detection rotor 47 continue to stop at the base point position of the rotor 57, and a constant voltage of, for example, 5V is detected by the Hall IC (circle 12 to circle 14 in the figure: Corresponding to Step 2 to Step 0 in FIG. 4).

  In the next step, the N pole and S pole of the rotor 57 are attracted to the N pole and S pole of the opposite phases (following magnetic poles) of the stator 55, and the rotor 57 moves in the direction opposite to the one direction (the other direction). Inverts the inversion length of the step. Here, the detection rotor 47 is rotatable relative to the rotor 57, and the interval R1 between the protrusions 57b and 57c of the rotor 57 is the idling of the rotor 57 more than its reverse length (or reverse angle). The intervals are as large as possible. Therefore, even if the rotor 57 is attracted to the opposite phase and reversed by the reverse length (or reverse angle), the protrusion 47a of the detection rotor 47 does not contact the protrusions 57b and 57c of the rotor 57, and the detection rotor 47 Does not reverse following the reversal of the rotor 57, but continues to stop at the base point position of the rotor 57, and a constant voltage of, for example, 5V is detected by the Hall IC (circle 15 in the figure: corresponding to step 7 in FIG. 4) ).

  Thereafter, even if the N pole and S pole of the stator 55 are switched and the rotor 57 rotates, the protrusion 47a of the detection rotor 47 is disposed between the protrusions 57b and 57c of the rotor 57, and the detection rotor 47 is the rotor 57. Continue to stop at the base point position. At that time, a biasing force that suppresses the rotation of the detection rotor 47 is applied by a magnetic field formed around the detection rotor 47 by the magnetic body 46, and a constant voltage of, for example, 5 V is detected by the Hall IC (see FIG. Middle, circle 16: corresponding to step 6 in FIG. By detecting the constant voltage of the Hall IC 45, it is possible to reliably detect that the rotor 57 has reached the predetermined base position (perform the base position of the rotor 57).

  When the rotor 57 rotates in another direction (for example, counterclockwise as viewed from above in FIG. 1), the detection rotor 47 continues to stop for a certain step, that is, the detection rotor 47 has a predetermined driving play. In a certain step, the projection 57b provided on the upper surface of the rotor 57 and the projection 47a provided on the lower surface of the detection rotor 47 come into contact with each other, and then the rotor 57 drives the detection rotor 47 via the projections 57b and 47a. The force is transmitted, the detection rotor 47 rotates with the rotor 57, and a rectangular waveform output signal is detected by the Hall IC provided outside the detection rotor 47.

  As described above, in this embodiment, the rotational driving force is transmitted from the rotor 57 to the detection rotor 47 by the two protrusions 57b and 57c provided on the upper surface of the rotor 57 and the rod-like protrusion 47a provided on the lower surface of the detection rotor 47. The rotary drive mechanism is configured, and this rotary drive mechanism has a drive play of a predetermined length or angle in the rotation direction of the rotor 57, specifically, a drive play greater than the reverse length or reverse angle of the rotor 57. Therefore, the transmission of the rotational driving force from the rotor 57 to the detection rotor 47 when the rotor 57 is reversed is restrained by the length or angle of the driving play, so that the valve body 25 is surely closed the valve port 22a. (The precise positioning of the base point of the rotor 57 can be performed), the continuous abnormal noise and vibration of the motor-operated valve and the decrease in durability of the motor-operated valve can be suppressed, and the stepping motor 5 It is possible to suppress unnecessary driving of the stator 55.

  In the above-described embodiment, when the valve body 25 closes the valve port 22a, the stopper 37 of the valve body holder 32 comes into contact with the stopper 27 of the guide bush 26, and rotation stops at the valve closing position of the valve port 22a. Although the mode in which the rotation of the rotor 57 is prevented by the mechanism has been described, a configuration may be adopted in which a slight fluid leakage is allowed when the valve is closed, and for example, the fully open position of the valve body 25 (the end position of the rotor 57). ) And the like, a rotation stop mechanism for preventing the rotation of the rotor 57 can be set at an appropriate position, and a desired rotation position of the rotor 57 can also be detected.

  In the above-described embodiment, the detection rotor 47 is placed on the support portion 56 a formed on the rotation shaft 56 of the rotor 57, and is disposed so as to be rotatable relative to the rotation shaft 56 of the rotor 57. Although the embodiment has been described, for example, the detection rotor 47 and the rotating shaft 56 are integrated, the rotating shaft 56 is loosely fitted to the upper reduced diameter portion 25b of the valve body 25, and the lower portion of the rotating shaft 56 is placed on the upper portion of the valve body holder 32. The detection rotor 47 and the rotation shaft 56 may be integrally mounted so as to be rotatable relative to the rotor 57, the support ring 36, and the valve body holder 32.

  6 schematically shows the basic configuration of another embodiment of a stepping motor applied to the motor-operated valve shown in FIG. 1, and FIG. 7 is a cross-sectional view taken along the line BB in FIG. is there.

  The stepping motor 50A of the embodiment shown in FIGS. 6 and 7 differs from the stepping motor 50 shown in FIGS. 2 and 3 in the configuration of the rotation drive mechanism and the rotation stop mechanism, and the other configurations are the same as those in FIG. And it is substantially the same as the stepping motor 50 shown in FIG. Therefore, the same components as those of the stepping motor 50 shown in FIGS. 2 and 3 are denoted by the same reference numerals, and detailed description thereof is omitted.

  On the upper surface of the rotor 57A shown in FIG. 6, a recess (drive play recess) 57Ad having a predetermined length interval (or angular interval) is formed in the rotational direction of the rotor 57A, and the detection is arranged above the rotor 57A. On the lower surface of the rotor 47A, a rod-like protrusion 47Aa whose tip is loosely fitted in the recess 57Ad of the rotor 57A is provided. Here, the recess 57Ad is formed inside the outer edge of the upper surface of the rotor 57A. In this way, the tip end of the rod-shaped protrusion 47Aa is loosely fitted in the recess 57Ad of the rotor 57A, so that the detection rotor 47A has a predetermined length (or angle) in the rotation direction of the rotor 57A, that is, the recess 57Ad of the rotor 57A. The side surface 57Ab and the side surface 57Ac are rotatable relative to the rotor 57A inside the length interval (or angular interval) R2 (that is, within the range of R2) (see FIG. 7). The interval R2 is set so that the rod-shaped protrusion 47aA of the detection rotor 47A can rotate more than the reverse length (or reverse angle) of the rotor 57A, as in the case of the above-described interval R1.

  When the rotor 57A is rotationally driven in one direction (for example, clockwise when viewed from above in the drawing) in a state where the rod-shaped protrusion 47Aa of the detection rotor 47A is in contact with the side surface 57Ac of the recess 57Ad of the rotor 57A, the rotor 57A Is transmitted to the detection rotor 47A, and the detection rotor 47A follows the rotor 57A and forcibly rotates in the one direction. On the other hand, when the rotor 57A is rotationally driven in another direction (for example, counterclockwise as viewed from above in the figure) in a state where the rod-like protrusion 47Aa of the detection rotor 47A is in contact with the side surface 57Ab of the recess 57Ad of the rotor 57A. The detection rotor 47A is forced to rotate in the other direction following the rotor 57A.

  A stopper 58Aa is fixed below the rotor 57A of the can 58, and a stopper 57Aa is provided on the lower surface of the rotor 57A. When the rotor 57A rotates in a single direction by a predetermined number of rotations, the stopper 57Aa and the stopper 58Aa. The rotor 57A is prevented from rotating. That is, in the embodiment shown in FIGS. 6 and 7, the rotation stop mechanism 59A that prevents the rotation of the rotor 57A is configured by the stopper 57Aa provided in the rotor 57A and the stopper 58Aa provided in the can 58.

  As described above, in the embodiment shown in FIGS. 6 and 7, the rotational driving force from the rotor 57A to the detection rotor 47A is provided by the recess 57Ad provided on the upper surface of the rotor 57A and the rod-shaped protrusion 47Aa provided on the lower surface of the detection rotor 47A. The rotational drive mechanism is configured to have a drive play with a predetermined length or angle in the rotational direction of the rotor 57A, for example, a drive play greater than or equal to the reverse length or reverse angle of the rotor 57A. The transmission of the rotational driving force from the rotor 57A to the detection rotor 47A when the rotor 57A is reversed is suppressed by the length or angle of the driving play. Therefore, even if the supply of drive current to the stator 55 is continued after the rotor 57A is forcibly stopped by the rotation stopper mechanism 59A, the detection rotor 47A remains stopped only by the vibration of the rotor 57A, and the rotor 57A is stopped. Can accurately detect the contact of the rotor 57A and accurately determine the position of the base point of the rotor 57A, for example, it is possible to suppress the continuous abnormal noise and vibration of the motorized valve and the deterioration of the durability of the motorized valve, Unnecessary driving of the stator of the stepping motor can be suppressed.

  In the above-described embodiment, the rotor 57 is provided with two protrusions 57b and 57c arranged at intervals in the rotation direction, and the detection rotor 47 is disposed between the two protrusions 57b and 57c of the rotor 57. A form in which the protrusion 47a is provided, or a form in which the rotor 57A is provided with a recess 57Ad having a predetermined length interval (or angular interval) in the rotation direction, and a form in which the detection rotor 47A is provided with a protrusion 47Aa loosely fitted in the recess 57Ad of the rotor 57A. As described above, for example, the detection rotor 47 may be provided with a plurality of protrusions arranged at intervals in the rotation direction, and the rotor 57 may be provided with a protrusion arranged between the plurality of protrusions of the detection rotor 47. The rotor 47A is provided with a recess having a predetermined length interval (or angular interval) in the rotation direction, and the rotor 57A is provided with a protrusion loosely fitted in the recess of the detection rotor 47A. It may be. Further, the position and shape of the protrusions and recesses of the rotor can be changed as appropriate.

  Further, in the above-described embodiment, the distance R1 between the protrusions 57b and 57c of the rotor 57 and the side surface 57Ab of the recess 57Ad of the rotor 57A so that the detection rotors 47 and 47A do not rotate when the rotors 57 and 57A are reversed. In this embodiment, the distance R2 between the 57Ac is set to be equal to or greater than the reversal length (or reversal angle) of the rotor. For example, the distance R1 between the protrusions 57b and 57c of the rotor 57 and the side surfaces 57Ab and 57Ac of the recess 57Ad Even when the interval R2 is smaller than the reversal length (or reversal angle) of the rotor, there is a range in which the detection rotors 47 and 47A do not rotate following the rotors 57 and 57A when the rotors 57 and 57A are reversed. Since it is present (ie, there is drive play), it can be reliably distinguished from the normal drive waveform, and the rotors 57 and 57A It is possible to perform the point positioning precisely.

  In the above-described embodiment, the stopper 37 provided on the valve body holder 32, the stopper 27 provided on the guide bush 26, the stopper 57Aa provided on the rotor 57A, and the stopper 58Aa provided on the can can be used. Although the description has been given of the configuration in which the rotation stop mechanism for preventing the rotation is configured, the configuration of the rotation stop mechanism can be appropriately changed as long as the rotation of the rotor disposed inside the stator can be prevented.

  Further, in the above-described embodiment, the mode in which the rotation of the rotor is suppressed by the magnetic field formed around the rotor by the magnetic body 46 has been described. However, for example, the rotation of the rotor is performed by an appropriate biasing force such as frictional resistance. It may be suppressed.

  Further, in the above-described embodiment, the stepping motor according to the present invention is applied to the motor-operated valve, and the mode in which the rotor base point is positioned when the valve body reaches a predetermined position has been described. The stepping motor can be applied to devices other than the motor-operated valve that needs to detect a predetermined rotational position of the rotor.

DESCRIPTION OF SYMBOLS 1 Motorized valve 20 Valve body 21 Valve chamber 22a Valve port 24 Valve body part 25 Valve body 26 Guide bush 27 Stopper 32 Valve body holder 37 Stopper 45 Hall IC
46 Magnetic body 47 Detection rotor 47a Rod-like protrusion 50 Stepping motor 55 Stator 56 Rotating shaft 57 Rotor 57Aa Rotor side stopper 57b, 57c Protrusion 57Ad Concavity (drive play concavity)
58Aa Can side stopper 59 Rotation stop mechanism L Rotation axis

Claims (9)

A stepping motor comprising a stator and a rotor driven to rotate by the stator,
A detection rotor for detecting the rotational position of the rotor;
The detection rotor is rotatably arranged coaxially with the rotor and is rotationally driven by the rotor via a rotational drive mechanism between the rotor and the detection rotor.
The rotational drive mechanism has a drive play of a predetermined length or angle in the rotational direction,
A stepping motor characterized in that transmission of rotational driving force from the rotor to the detection rotor is suppressed within a range of the length or angle of the driving play when the rotor is reversed. A stepping motor comprising a stator and a rotor driven to rotate by the stator,
A detection rotor for detecting the rotational position of the rotor;
The detection rotor is rotatably arranged coaxially with the rotor and is rotationally driven by the rotor via a rotational drive mechanism between the rotor and the detection rotor.
The rotation drive mechanism is provided on one of the rotor and the detection rotor, and has a plurality of protrusions arranged at predetermined length intervals or angular intervals in the rotation direction, and any one of the rotor and the detection rotor. Or a separate protrusion disposed between the plurality of protrusions, wherein the separate protrusion is relatively movable between the plurality of protrusions. Stepping motor characterized by A stepping motor comprising a stator and a rotor driven to rotate by the stator,
A detection rotor for detecting the rotational position of the rotor;
The detection rotor is rotatably arranged coaxially with the rotor and is rotationally driven by the rotor via a rotational drive mechanism between the rotor and the detection rotor.
The rotation drive mechanism is provided in one of the rotor and the detection rotor, and is provided in a drive play recess having a predetermined length interval or angular interval in the rotation direction, and in the other of the rotor and the detection rotor. And a protrusion freely fitted in the drive play recess, wherein the protrusion has a drive play that is relatively movable inside the drive play recess. motor. A rotation stop mechanism for preventing rotation of the rotor;
The length or angle of the driving play of the rotation drive mechanism is equal to or greater than the reversal length or reversal angle of the rotor when the rotation of the rotor is blocked by the rotation stop mechanism. The stepping motor according to any one of items 1 to 3.   5. The stepping motor according to claim 1, wherein a biasing force that suppresses rotation of the detection rotor is applied to the detection rotor.   The stepping motor according to claim 5, wherein the urging force is generated by a magnetic body provided outside the detection rotor. Including the stepping motor according to any one of claims 1 to 6,
A valve body having a valve chamber and a valve opening that opens to the valve chamber; a valve body disposed to be movable up and down in the valve chamber so as to open and close the valve port; and a rotational movement of the rotor of the stepping motor. A conversion mechanism for converting the body into a lifting motion,
The stepping motor rotates the rotor by the stator and raises and lowers the valve body by the conversion mechanism so that the rotation of the rotor is blocked by a rotation stop mechanism when the valve body reaches a predetermined position. A motor-operated valve characterized by being configured as described above.   The electrically operated valve according to claim 7, wherein the predetermined position is a position where the valve body closes the valve port or a position where the valve body fully opens the valve port. A can is fixed to the valve body,
The motor-operated valve according to claim 7 or 8, wherein the rotor and the detection rotor are disposed inside the can.

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