JP4483526B2 - Electric actuator - Google Patents

Description

  The present invention relates to an electric actuator that rotates an output shaft by driving an electric motor and generates a pulse signal based on the rotation of the output shaft.

  Conventionally, in an electric actuator of a vehicle air conditioner, as shown in FIG. 12, an electric motor 1 and a speed reduction mechanism 2 that decelerates the rotational force input from the electric motor 1 and outputs the reduced speed from the output shaft 2a to the door. Have been proposed (for example, see Patent Document 1).

  Here, the speed reduction mechanism 2 includes a pulse pattern plate 3 that rotates integrally with the output shaft 2a, and the pulse pattern plate 3 includes two conductive portions and non-conductive portions that are alternately arranged in the circumferential direction. Pulse patterns 3a and 3b are provided. Furthermore, brushes 4a and 4b are provided which are connected to the positive terminal of the battery and come into contact with the two pulse patterns 3a and 3b, respectively.

  In this case, when the electric motor 1 rotates and the pattern plate 3 rotates, the energized (ON) state where the brush 4a and the conductive part of the pulse pattern 3a are in contact, and the non-conductive part of the brush 4a and the pulse pattern 3a are Non-energized (OFF) states that contact each other periodically occur.

  Also, between the brush 4b and the pulse pattern 3b, the energization (ON) state where the brush 4b and the conductive part of the pulse pattern 3b are in contact and the non-energization where the brush 4b and the non-conductive part of the pulse pattern 3b are in contact. (OFF) states occur periodically with respect to each other.

  Therefore, each time the electric motor 1 rotates by a predetermined angle, the A and B phase angle detection pulse signals are generated in the brushes 4a and 4b, and the level changes of the A and B phase angle detection pulse signals are changed. The rotation angle of the output shaft 2a can be detected by counting.

  The A phase and B phase angle detection pulse signals are signals having different phases, and by detecting which one of the A phase and B phase angle detection pulse signals changes in level first. The rotation direction of the output shaft 2a can be detected. The rotation angle and rotation direction of the output shaft 2a detected as described above are used for controlling the door operating angle.

  In addition, when controlling the operating angle of the door, as an initialization process, a process for returning the output shaft 2a to the initial position is necessary, and it is possible to determine whether or not the output shaft 2a is actually located at the initial position. It is also necessary to keep it.

  On the other hand, the present applicant provides an initialization area in the pattern plate 3, and when the output shaft 2a reaches the initial position, the brushes 4a and 4b come into contact with the initialization area, replacing the normal angle detection pulse signal. A patent application was filed for an electric actuator that generates an initial position pulse signal (Japanese Patent Application No. 2002-36392).

  In this, the initialization region is provided with conductive portions and non-conductive portions having patterns different from the above-described pulse patterns 3a and 3b, and the pulse pattern of the initial position pulse signal is the same as the pulse pattern of the normal angle detection pulse signal. It is different.

For this reason, since it becomes possible to determine whether or not the output shaft 2a has reached the initial position by identifying the pulse pattern of the pulse signal, it is possible to perform an initialization process for returning the output shaft 2a to the initial position. Become.
Japanese Patent Laid-Open No. 2002-354885

  By the way, in the electric actuator described in Patent Document 1 described above, in order to generate the angle detection pulse signal from the brushes 4a and 4b, it is necessary to bring the brushes 4a and 4b into contact with the pulse pattern plate 3.

  Further, even in the electric actuator described in the prior application filed by the present applicant, in order to generate the initial position pulse signal from the brushes 4a and 4b, the brushes 4a and 4b are brought into contact with the initialization region of the pulse pattern plate 3. It will be necessary.

  As described above, in the above-described two electric actuators, it is necessary to bring the brushes 4a and 4b into contact with the pulse pattern plate 3, respectively. Therefore, mechanical wear occurs and durability becomes poor.

  In view of the above, an object of the present invention is to provide an electric actuator having improved durability by eliminating mechanical wear caused by a brush.

  The present invention focuses on the fact that a pulse signal can be generated in a mechanically non-contact structure by providing a magnet that rotates with the rotation of the output shaft and utilizing a magnetic field change generated from this magnet. It was made as a result.

Specifically, in the invention according to claim 1, an electric motor (110);
As shown in FIG. 3 and FIG. 4, a front gear (124) that meshes with and rotates with the gear (123) on the electric motor side,
Rotational force is transmitted from the front-stage gear by being spaced from the front-stage gear in the rotational axis direction (see FIG. 4) and overlapping the front-stage gear in the radial direction (see FIG. 5). A rear gear (126) that rotates based on the rotational force transmitted through the path (125);
An output shaft (127) for transmitting the rotational force from the rear gear to the movable parts (11a, 11b,... 11e);
A multi-pole magnet (130: see FIG. 5) provided on one gear (124) of the front-stage side gear and the rear-stage side gear, wherein N poles and S poles are alternately arranged in the circumferential direction;
As shown in FIG. 4, a magnetic sensor (140a) disposed in a position overlapping in the radial direction between the first and second gears and detecting a magnetic field generated from the multipolar magnet in a non-contact manner,
An initial arrangement that is arranged on the other gear (126) of the front-side gear and the rear-side gear, and that applies a magnetic field to the magnetic sensor without contact only when the output shaft reaches an initial position. The magnetic sensor is applied with magnetic fields of different directions alternately with the rotation of the multi-pole magnet, and the magnetic sensor is applied with the magnetic field applied to the magnetic sensor. An angle detection pulse signal whose level changes based on the change in direction of
Furthermore, as shown in FIG. 10, only when the output shaft reaches the initial position, the magnetic sensor responds to the combined magnetic field of the magnetic field from the initial position side magnet and the magnetic field from the multipolar magnet. An initial position pulse signal having a pulse pattern different from that of the angle detection pulse signal is generated.

  According to the first aspect of the present invention, the magnetic sensor can generate an angle detection pulse signal without contact with the multipolar magnet. In addition, the magnetic sensor can generate an initial position pulse signal without contact with both the multi-pole magnet and the initial position side magnet.

  As described above, the magnetic sensor can generate an angle detection pulse signal and an initial position pulse signal with a non-contact structure between the multipolar magnet and the initial position side magnet. That is, since the angle detection pulse signal and the initial position pulse signal can be generated without causing mechanical wear, the mechanical wear due to the brush can be eliminated and the durability can be improved.

  In the conventional electric actuator, the number of pulses with respect to the rotation angle (that is, the number of pulses of the angle detection pulse signal) is determined by the size of the conductive portion and the non-conductive portion of the pulse pattern plate.

  That is, if the conductive parts and non-conductive parts are made small, the number of conductive parts and non-conductive parts that constitute the pulse pattern plate can be increased, so the number of pulses with respect to the rotation angle increases and the rotation angle detection accuracy is increased. can do.

  However, mechanical wear occurs between the conductive part and the non-conductive part with the brush. For this reason, in order to maintain a lifetime of a certain period or longer, there is a limit to the miniaturization of the conductive part and the non-conductive part, and thus the rotational angle detection accuracy is also limited.

  On the other hand, according to the first aspect of the present invention, as described above, no mechanical wear occurs between the magnetic sensor (or other magnetic sensor) and the multipolar magnet. The size of the S and N poles can be reduced, and the number of S and N poles can be easily increased (that is, the number of poles can be increased). Therefore, it is possible to increase the rotation angle detection accuracy by increasing the number of pulses with respect to the rotation angle as compared with the conventional case.

  In addition, as a multipolar magnet, as in the invention described in claim 7, it is necessary that the pair of the N pole and the S pole are arranged at a certain angle in the circumferential direction.

  Further, as in the second aspect of the invention, only when the output shaft reaches the initial position, the magnetic field applied from the multipolar magnet to the magnetic sensor is caused by the magnetic field from the initial position side magnet. You may make it cancel.

According to a third aspect of the invention, in the electric actuator according to the first or second aspect, in addition to the magnetic sensor (140a), a magnetic field generated from the multipolar magnet is detected in a non-contact manner, and the multiple Another magnetic sensor (140b) that generates an angle detection pulse signal based on the magnetic field from the polar magnet is provided,
The other magnetic sensor (140b) and the magnetic sensor (140a) are arranged so as to generate the angle detection pulse signals having different phases.

According to invention of Claim 3, the angle detection pulse signal from another magnetic sensor,
The rotation direction of the output shaft is detected by detecting which angle detection pulse signal from the angle detection pulse signal from the magnetic sensor first changes in level (for example, change from high level to low level). be able to.

  According to a fourth aspect of the present invention, in the electric actuator according to the third aspect, only the magnetic field from the multipolar magnet is applied to the other magnetic sensor even when the output shaft reaches an initial position. It may be like this.

  Here, in the invention according to claim 5, the torque transmission path includes an intermediate gear (125) that rotates coaxially with the front gear and transmits the torque to the rear gear. You may do it. In particular, according to a sixth aspect of the present invention, the intermediate gear (125) may mesh with the rear stage side gear and transmit a rotational force to the rear stage side gear.

  In addition, the code | symbol in the bracket | parenthesis of each said means shows the correspondence with the specific means as described in embodiment mentioned later.

  FIG. 1 shows an electric actuator system according to an embodiment of the present invention applied to a vehicle air conditioner that performs air conditioning in a passenger compartment. Below, the outline of a vehicle air conditioner is demonstrated using FIG.

  The vehicle air conditioner includes an air conditioning case 10 housed in an instrument panel. In the air conditioning case 10, an inside / outside air switching door 11a is rotatably supported by the air conditioning case 10 and is driven by a servo motor 100a. The first switching position (position indicated by a solid line in the figure) and the second switching position (position indicated by a broken line in the figure) are switched from one to the other.

  Here, when the inside / outside air switching door 11a is switched to the first switching position, the outside air is introduced into the air conditioning case 10 from the outside air inlet 15a as the outside air introduction mode, while the second switching position (FIG. Is switched to the position indicated by the broken line), the air in the vehicle compartment (inside air) flows into the air conditioning case 10 from the inside air introduction port 15b as the inside air introduction mode.

  The blower 12 blows the outside air from the outside air introduction port 15a or the inside air from the inside air introduction port 15b to the evaporator 13 as an air flow according to the rotational speed of the blower motor 12a (DC motor). The blown air flow is cooled by a refrigerant circulating by the operation of a known refrigeration cycle.

  The air mix door (A / M door) 11b is driven by the servo motor 100b, and the cooling air flow blown from the evaporator 13 flows into the heater core 15 and the air flow that bypasses the heater core 15 (hereinafter referred to as bypass cooling air flow). And).

  Since the airflow flowing into the heater core 15 is heated by the engine cooling water (hot water) in the heater core 15, the hot air is blown out from the heater core 15. Accordingly, the warm air blown out from the heater core 15 and the bypass cooling airflow are mixed and flow toward the outlet doors 15c, 15d, and 15e. Here, the mixing ratio SW (%) between the warm air and the bypass cooling air flow is determined by the opening degree of the air mix door 11b.

  The blowout door 11c is switched from the first switching position (the position indicated by the solid line in the figure) to the second switching position (the position indicated by the broken line in the figure) in the differential mode under the drive of the servo motor 100c. The part 15c is opened and air is blown out mainly from the opening 15c toward the front windshield.

  The air outlet door 11e is switched from a first switching position (a position indicated by a solid line in the drawing) to a second switching position (a position indicated by a broken line in the drawing) in the face mode under the drive of the servo motor 100a. The portion 15e is opened, and air is blown out from the opening 15e toward the passenger's upper body in the passenger compartment.

  The air outlet door 11d is switched from the first switching position (the position indicated by the solid line in the figure) to the second switching position (the position indicated by the broken line in the figure) in the foot mode under the drive of the servo motor 100a. The opening 15d is opened and air is blown out from the opening 15d toward the passenger's lower half of the passenger compartment.

  Each of the doors 11a to 11e is formed into a plate shape with resin or the like. Hereinafter, the air outlet doors 11c, 11d, and 11e are also referred to as a differential air outlet door 11c, a foot air outlet door 11d, and a face air outlet door 11e, respectively.

  The air conditioner electronic control device 400 is a well-known device including a memory, a microcomputer, and the like. The air conditioner electronic control device 400 includes a vehicle interior temperature detected by the inside air temperature sensor S1 and a solar radiation sensor S2. Based on the detected solar radiation intensity in the passenger compartment, the temperature outside the passenger compartment detected by the outside air temperature sensor S3, the set temperature output from the temperature setter Re set by the occupant, and the like, a known target blowing temperature Calculate TAO.

  Here, the target blowing temperature TAO is a blowing air temperature necessary for maintaining the passenger compartment at a set temperature regardless of changes in environmental conditions (vehicle thermal load conditions).

  The air conditioner electronic control unit 400 determines the target air volume of the blower 12 (that is, the voltage applied to the blower motor 12a) and the target position of the inside / outside air switching door 111b based on the target blowing temperature TAO (that is, first and second). The target position (target opening degree) of the air mix door 11b, the target positions of the outlet doors 11c, 1e, and 1d are determined.

  The air conditioner electronic control unit 400 communicates with the servo motors 100a to 100c through the communication line, individually transmits the target positions (target angles), and the servo motors 100a to 100c have their respective target positions. Until the doors 11a, 11b, 11c, 11d, and 11e are rotated independently. Furthermore, the air conditioner electronic control unit 400 controls the blower motor 9a so that the air volume blown from the blower 12 becomes the target air volume.

  Here, each of the servo motors 100a to 100c has a substantially similar structure. Hereinafter, the servo motor 100a will be described as an example of the servo motors 100a to 100c.

  FIG. 2 is an external view of the servo motor 100a, and FIG. 3 is a configuration diagram of the servo motor 100a. In FIG. 4, the servo motor 100 a includes a casing 150 that houses the DC motor 110 and the speed reduction mechanism 120. The DC motor 110 rotates by obtaining electric power from a battery mounted on the vehicle, and the speed reduction mechanism 120 is a speed change mechanism that decelerates the rotational force input from the motor 110 and outputs it to the inside / outside air switching door 11a. is there.

  Here, the speed reduction mechanism 120 is a gear composed of a worm 121 press-fitted into the output shaft 111 of the motor 110, a worm wheel 122 meshing with the worm 121, a plurality of intermediate spur gears 123, 124, 125, and an output gear 126. This output gear 126 is provided with an output shaft 127. Note that the various gears 121 to 126 are formed of, for example, a resin material.

  Here, the intermediate spur gear 124 rotates about the rotation shaft 125, and the intermediate spur gear 125 rotates coaxially with the intermediate spur gear 124 and meshed with the output gear 126. The intermediate spur gear 124 and the output gear 126 have the rotation shafts 124a and 127 parallel to each other, and as shown in FIGS. 4 and 5, are spaced apart in the rotation axis direction and in the radial direction. They are arranged so as to overlap.

  A multi-pole magnet 130 is fixed to the back side of the intermediate spur gear 124 (the lower side in the drawing in FIG. 4) with, for example, an adhesive, and the multi-pole magnet 130 rotates in accordance with the rotation of the intermediate spur gear 124. To do.

  As shown in FIG. 5 and FIG. 6, the multipolar magnet 130 has N poles and S poles alternately arranged in the circumferential direction at a constant angle θ (for example, 22.5 degrees), and a pair of N poles. And S poles are ring-shaped magnets arranged at a constant angle 2θ (for example, 45 degrees).

  5 is an enlarged view as viewed in the direction of arrow A in FIG. 4, and FIG. 6 is an enlarged view of the intermediate spur gear 124 and the multipolar magnet 130.

  Further, an initial position side magnet 160 is fixed to the front side of the output gear 126 (the upper side in the drawing in FIG. 4), and the initial position side magnet 160 is disposed with a gap between the multipolar magnet 130. Yes. The initial position side magnet 160 is a plate-like magnet having an area substantially equal to (or slightly smaller than) the S pole (or N pole) of the multipolar magnet 130, and the initial position side magnet 160 is an output gear. Rotates with 126 rotation.

  Here, the N pole of the initial position side magnet 160 is arranged on the radially outer side and faces a part of the multipolar magnet 130, and the S pole of the initial position side magnet 160 is arranged on the radially inner side. The N pole of the initial position side magnet 160 is arranged so as to face a magnetic sensor 140a described later when the output shaft 127 is located at the initial position.

  Magnetic sensors 140a and 140b are provided on the back side of the intermediate spur gear 124 (the lower side in FIG. 4). The magnetic sensors 140a and 140b are fixed by the casing 150 via the printed circuit board 180, respectively. Yes.

  Here, the magnetic sensors 140a and 140b are disposed on the rotation trajectory of the multipolar magnet 130, and the magnetic sensors 140a and 140b are disposed at a certain angle (0.5 ± 2n) × θ degrees. Therefore, one of the magnetic sensors 140a and 140b faces either the S pole or the N pole of the multipolar magnet 130, and the other magnetic sensor faces an intermediate position between the S pole and the N pole.

  Here, the magnetic sensor 140a is disposed at a portion overlapping in the radial direction between the output gear 126 and the intermediate gear 124, and detects a magnetic field generated from the multipolar magnet 130 in a non-contact manner, as will be described later. Generate an angle detection pulse signal. The magnetic sensor 140a outputs an initial position pulse signal indicating the initial position of the output shaft 127 according to the magnetic field generated from the initial position side magnet 160 and the magnetic field generated from the multipolar magnet 130, as will be described later.

  The magnetic sensor 140 b is disposed on the back side (the lower side in the drawing in FIG. 4) of the intermediate spur gear 124, faces a part of the multipolar magnet 130, and deviates from the rotation locus of the initial position side magnet 160. The magnetic sensor 140b detects only the magnetic field generated from the multipolar magnet 130 in a non-contact manner, and generates a pulse signal as will be described later.

  Here, as the magnetic sensor 140a (140b), a Hall element that generates a pulse signal whose level changes in accordance with a change in the direction of the magnetic field is employed. Specifically, in the magnetic sensor 140a (140b), when the magnetic pole to be detected (that is, the magnetic pole facing the magnetic sensor) is switched from the S pole to the N pole, the amplitude of the pulse signal changes from the low level to the high level. To do. On the other hand, when the magnetic pole to be detected is switched from N pole to S pole, the amplitude of the pulse signal changes from high level to low level.

  Hereinafter, a pulse signal generated from the magnetic sensor 140a is referred to as an A-phase pulse signal, and a pulse signal generated from the magnetic sensor 140b is referred to as a B-phase pulse signal.

  Further, as shown in FIG. 2, a link lever 170 that swings the air mix door 11b is press-fitted and fixed to the output shaft 127, and the air conditioning casing 10 is provided with stoppers 11g and 11h. For this reason, the air mix door 11b (that is, the output shaft 127) swings within the operating range between the stoppers 11g and 11h. The stoppers 11g and 11h are used to stop the rotation of the motor by causing the link lever 170 to collide when electrical regulation of the rotation of the DC motor 110 fails.

  Next, the electric circuit configuration of the servo motor 100a will be described with reference to FIG. FIG. 7 is a block diagram showing an electric circuit configuration of the servo motor 100a.

  The servo motor 100a includes a control circuit 200. The control circuit 200 includes a motor driving circuit 210, a constant voltage circuit 211, a CPU 212, a pulse detection circuit 220, and a storage circuit 230.

  The motor drive circuit 210 is a circuit that drives the DC motor 110 under the control of the CPU 212, and the constant voltage circuit 211 converts the battery voltage applied from the in-vehicle battery through the power supply line into a constant voltage, and the circuits 212 and 220. , 230.

  The CPU 212 communicates with the air conditioner electronic control device 400 via a communication line, and controls the motor drive circuit 210 in accordance with the pulse signal detected by the pulse detection circuit 220. The storage circuit 230 stores a computer program executed by the CPU 212 and the like. The pulse detection circuit 220 shapes the waveform of the A-phase pulse signal and the B-phase pulse signal and outputs them to the CPU 212.

  Next, the operation of the servo motor 100b will be described. First, when the output shaft 111 of the electric motor 110 rotates, the rotational force is transmitted to the output gear 126 through the worm 121, the worm wheel 122, and the intermediate spur gears 123-125.

  At this time, the intermediate spur gear 124 rotates clockwise, and the output gear 126 rotates clockwise. Along with this, the multi-pole magnet 130 rotates clockwise, and the initial position side magnet 160 rotates clockwise.

  Here, before the output shaft 127 reaches the initial position, the magnetic sensor 140 a detects only the magnetic field from the multipolar magnet 130. That is, magnetic fields having different directions are alternately applied to the magnetic sensor 140a as the multipolar magnet 130 rotates. As shown in FIG. 8A, the magnetic sensor 140a generates an A-phase pulse signal whose level changes regularly based on the change in the direction of the applied magnetic field.

  On the other hand, in the magnetic sensor 140b, magnetic fields having different directions are alternately applied. As shown in FIG. 8 (b), the B phase whose level changes regularly based on the change in the direction of the applied magnetic field. Generate a pulse signal.

  As described above, the rising timing (or falling timing) of the A-phase and B-phase pulse signals whose levels change is counted by the CPU 212, and the rotation angle of the output shaft 127 is detected by the CPU 212.

  Here, as described above, since the magnetic sensors 140a and 140b are arranged with a deviation of (0.5 ± 2n) × θ degrees, the A-phase and B-phase pulse signals are transmitted in the pulse period Tp (high-level period). ) Half of the period Th (= Tp / 2). For this reason, the CPU 212 detects the rotation angle with a resolution in which a half angle (θ / 2) of the constant angle θ (= 22.5 degrees) is the minimum angle.

  Further, the CPU 212 detects which one of the A-phase pulse signal and the B-phase pulse signal rises first, thereby detecting the rotation angle direction of the output shaft 127 (see FIG. 8).

  Next, when the output shaft 127 reaches the initial position, the magnetic sensor 140 a detects the magnetic field from the initial position side magnet 160 in addition to the magnetic field from the multipolar magnet 130.

  That is, a magnetic field from the N pole of the multipolar magnet 130 and a magnetic field from the N pole of the initial position side magnet 160 are applied to the magnetic sensor 140a, and both magnetic fields are canceled as shown in FIG. It is. Therefore, irregularity occurs in the level change in the A-phase pulse signal output from the magnetic sensor 140a. That is, the pulse pattern of the A-phase pulse signal at this time is different from the pulse pattern before the output shaft 127 reaches the initial position.

  First, before the output shaft 127 reaches the initial position, when the magnetic pole to be detected by the magnetic sensor 140a (140b) changes from the S pole to the N pole, the A phase pulse signal (B phase pulse signal) falls, When changing from the N pole to the S pole, the A phase pulse signal (B phase pulse signal) rises.

  In FIG. 9A, the rising time and the falling time of the A-phase pulse signal are indicated by chain lines. Hereinafter, the pulse signal output from the magnetic sensor 140a (140b) before the output shaft 127 reaches the initial position is also referred to as an angle detection pulse signal.

  On the other hand, when the output shaft 127 reaches the initial position, a magnetic field (arrow G2 in FIG. 10) from the initial position side magnet 160 is applied to the magnetic sensor 140a. (Arrow G3 in FIG. 10) is canceled out. For this reason, even if the magnetic pole of the multipolar magnet 130 to be detected by the magnetic sensor 140a changes from the S pole to the N pole or from the N pole to the S pole, the amplitude of the A-phase pulse signal changes. Instead, as shown in FIG. 9, the high level is maintained for a predetermined period Ts.

  Here, the predetermined period Ts is a time required for the multipolar magnet 130 to rotate by a fixed angle θ × 2/3 (67.5 degrees). During this predetermined period Ts, the B-phase pulse signal has a timing. It rises at t1, falls at timing t2, and rises at timing t3.

  When the CPU 212 detects such A-phase and B-phase pulse signals, the CPU 212 determines that the output shaft 127 is located at the initial position. Hereinafter, the pulse signal output from the magnetic sensor 140a when it is positioned at the initial position of the output shaft 127 is also referred to as an initial position pulse signal.

  When it is determined that the output shaft 127 is located at the initial position, the CPU 212 electrically restricts the rotation of the DC motor 110 by stopping the power supply to the DC motor 110 by the motor drive circuit 210. The position where the two-phase initial position pulse signal is detected is stored in the storage circuit 230 as the rotation start position.

  After that, the CPU 212 controls the DC motor 110 using the position shifted by a predetermined number of pulses from the rotation start position as an operation reference except when the battery is disconnected and when an abnormality occurs in the pulse signal.

  In other words, when the target position is designated by the air conditioner electronic control device 400, the CPU 212 counts the number of pulses corresponding to the target position (specifically, the rising timing) until the A and B phase pulse signals are counted. The DC motor 110 is driven. For this reason, it can be rotated to the target position of the output shaft 127 and eventually the inside / outside air switching door 11a.

  Next, the effect of this embodiment is demonstrated. That is, the actuator 100a according to the present embodiment is spaced apart in the rotation axis direction (see FIG. 4) with respect to the electric motor 110, the intermediate gear 124 that rotates while meshing with the intermediate gear 123 on the electric motor side. And an output gear 126 that is arranged so as to overlap with the intermediate gear 124 in the radial direction (see FIG. 5) and rotates based on the rotational force transmitted from the intermediate gear 124 via the intermediate gear 125, and the output gear 126. An output shaft 127 for transmitting the rotational force from the inside / outside air switching door 11a, a multi-pole magnet (130: see FIG. 5) provided on the intermediate gear 124 and having N and S poles alternately arranged in the circumferential direction; A magnetic sensor 140a that is disposed in a position overlapping in the radial direction between the gears 124 and 126 and detects a magnetic field generated from the multipolar magnet 130 in a non-contact manner, and the output gear 12 And an initial position side magnet 160 disposed so as to apply a magnetic field without contact to the magnetic sensor 140a only when the output shaft 124 reaches the initial position, and the magnetic sensor 140a includes: As the multipolar magnet 130 rotates, magnetic fields having different directions are alternately applied so that the magnetic sensor 140a generates an angle detection pulse signal whose level changes based on the change in the direction of the applied magnetic field. Further, as shown in FIG. 10, only when the output shaft 127 reaches the initial position (specified position), the magnetic sensor 140 a is connected to the magnetic field from the initial position side magnet 160 and the multipolar magnet 130. The initial position pulse signal with a pulse pattern different from the angle detection pulse signal is generated according to the combined magnetic field of And features.

  According to the present embodiment, the magnetic sensors 140a and 140b can generate an angle detection pulse signal without contact with the multipolar magnet 130. In addition to this, the magnetic sensor 140a can generate an initial position pulse signal in a non-contact manner with both the multipolar magnet 130 and the initial position side magnet 160. For this reason, an initial position signal and an angle detection pulse signal can be output without impairing durability.

  In the conventional electric actuator, the number of pulses with respect to the rotation angle (that is, the number of pulses of the angle detection pulse signal) is determined by the size of the conductive portion and the non-conductive portion of the pulse pattern plate.

  That is, if the conductive portions and the nonconductive portions are reduced, the number of conductive portions and nonconductive portions constituting the pulse pattern plate can be increased. For this reason, since the number of pulses with respect to the rotation angle increases, the rotation angle detection accuracy can be increased.

  However, mechanical wear occurs between the conductive part and the non-conductive part with the brush. For this reason, in order to maintain a lifetime of a certain period or longer, there is a limit to the miniaturization of the conductive part and the non-conductive part, and thus the rotational angle detection accuracy is also limited.

  On the other hand, according to the present embodiment, as described above, no mechanical wear occurs between the magnetic sensors 140a and 140b and the multipolar magnet 130. Therefore, the number of S poles and N poles of the multipolar magnet 130 is the same. The increase can be made easily. Therefore, it is possible to increase the rotation angle detection accuracy by increasing the number of pulses with respect to the rotation angle as compared with the conventional case.

(Other embodiments)
In the above-described embodiment, an example in which two sensors are used as the magnetic sensor has been described. However, the present invention is not limited to this, and only one magnetic sensor 140a may be employed as shown in FIG.

  In this case, when the output shaft 127 reaches the initial position, the magnetic field from the initial position side magnet 160 (arrow G2 in FIG. 10) is applied to the magnetic sensor 140a, as in the above-described embodiment. The amplitude of the signal does not change, and remains at a high level for a predetermined period Ts. Therefore, the CPU 212 determines that the output shaft 127 is located at the initial position when the level of the A-phase pulse signal becomes a high level for a certain period or longer.

  In the above-described embodiment, the example in which the actuator is applied to the vehicle air conditioner has been described. However, the present invention is not limited thereto, and the actuator may be applied to various industrial devices such as a home air conditioner and a commercial air conditioner.

  In the above-described embodiment, an example in which a magnet in which a pair of S poles and N poles are arranged over 360 degrees is used as the multipole magnet 130 is not limited to this. The angle at which the pair of S poles and N poles are arranged may be less than 360 degrees.

  In the above-described embodiment, an example in which two sensors 140a and 140b are provided as magnetic sensors has been described. However, the present invention is not limited to this, and three or more magnetic sensors may be provided.

  In the above-described embodiment, the example in which the multipole magnet 130 is provided in the intermediate gear 124 and the initial position side magnet 160 is provided in the output gear 126 has been described. The gear 126 may be provided, and the initial position side magnet 160 may be provided on the intermediate gear 124.

  In the above-described embodiment, the example in which the intermediate gear 125 is employed as the rotational force transmission path has been described. However, the present invention is not limited to this, and any configuration may be adopted as long as the configuration is transmitted to the rotational force output gear 126 from the intermediate gear 124. Good.

  For example, in the above-described embodiment, an example in which the intermediate spur gear 125 is arranged so as to mesh with the output gear 126 has been described. The intermediate spur gear 125 may transmit the rotational force to the output gear 126 via another intermediate spur gear.

  In the above-described embodiment, the example in which the output shaft 127 of the output gear 126 swings the link lever 170 to rotate the inside / outside air switching door 11a (movable part) has been described. An intermediate gear may be interposed between the output gear 126 and the link lever 170.

  In the above-described embodiment, an example has been described in which the intermediate spur gear 125 to which the rotational force is transmitted from the worm 121 via the gears 122, 123, and 124 is used as the front stage side gear. Alternatively, a gear that directly meshes with the worm 121 may be used.

  Hereinafter, the correspondence relationship between the above embodiment and the configuration of the scope of the claims will be described. The intermediate gear 123 corresponds to the gear on the electric motor side, the magnetic sensor 140a corresponds to the magnetic sensor according to claim 1, The magnetic sensor 140b corresponds to another magnetic sensor described in claim 3, the intermediate spur gear 124 and the output gear 126 correspond to the front gear and the rear gear, respectively, and the doors 11a, 11b, 11c, 11d, and 11e are provided. Each corresponds to a movable part, and the output shaft 127 corresponds to an output shaft.

It is a schematic diagram which shows the structure of the vehicle air conditioner to which the actuator of this invention is applied. It is a figure which shows the external appearance of the actuator of FIG. It is a figure which shows the internal structure of the actuator of FIG. It is a side view which shows the internal structure of the actuator of FIG. It is an A arrow directional view of the actuator in FIG. It is a figure which shows the multipolar magnet in FIG. It is a schematic diagram which shows the electrical structure of the actuator of FIG. It is a timing chart which shows the pulse signal output from two magnetic sensors in FIG. It is a timing chart which shows the pulse signal output from two magnetic sensors in FIG. It is a figure which shows the positional relationship of the magnetic sensor in FIG. 4, a multipolar magnet, and an initial position side magnet. It is a figure for demonstrating the modification of one Embodiment of this invention. It is a figure which shows the internal structure of the conventional actuator.

Explanation of symbols

100a to 100c ... actuator, 110 ... electric motor, 124 ... gear,
11a ... inside / outside air switching door, 127 ... output shaft, 130 ... multipolar magnet,
140a, 140b ... magnetic sensors, 160 ... initial position side magnets.

Claims (7)

An electric motor (110);
A front gear (124) that meshes with and rotates with the gear (123) on the electric motor side;
It is arranged to be spaced apart from the front stage side gear in the direction of the rotation axis and to overlap the front stage side gear in the radial direction, and is transmitted from the front stage side gear via the rotational force transmission path (125). A rear gear (126) that rotates based on the rotational force;
An output shaft (127) for transmitting the rotational force from the rear gear to the movable parts (11a, 11b,... 11e);
A multi-pole magnet (130) provided on one gear (124) of the front-side gear and the rear-side gear, wherein N poles and S poles are alternately arranged in a circumferential direction;
A magnetic sensor (140a) disposed in a position overlapping in the radial direction between the first and second gears and detecting a magnetic field generated from the multipolar magnet in a non-contact manner;
Initially arranged to apply the magnetic field to the magnetic sensor in a non-contact manner only when the output shaft reaches the initial position, disposed on the other gear (126) of the front-stage gear and the rear-stage gear. The magnetic sensor is applied with magnetic fields of different directions alternately with the rotation of the multi-pole magnet, and the magnetic sensor is applied with the magnetic field applied to the magnetic sensor. An angle detection pulse signal whose level changes based on the change in direction of
Further, only when the output shaft reaches the initial position, the magnetic sensor detects the angle detection pulse signal according to the combined magnetic field of the magnetic field from the initial position side magnet and the magnetic field from the multipolar magnet. An electric actuator characterized by generating initial position pulse signals of different pulse patterns. The magnetic field applied from the multipolar magnet to the magnetic sensor is canceled only by the magnetic field from the initial position side magnet only when the output shaft reaches the initial position. Item 4. The electric actuator according to Item 1. In addition to the magnetic sensor (140a), another magnetic sensor (140b) that detects a magnetic field generated from the multipolar magnet in a non-contact manner and generates an angle detection pulse signal based on the magnetic field from the multipolar magnet. Provided,
3. The electric actuator according to claim 1, wherein the other magnetic sensor (140b) and the magnetic sensor (140a) are arranged to generate the angle detection pulse signals having different phases. . The electric actuator according to claim 3, wherein only the magnetic field from the multipolar magnet is applied to the other magnetic sensor even when the output shaft reaches an initial position. The said rotational force transmission path | route is equipped with the intermediate | middle gear (125) which rotates coaxially with respect to the said front side gear, and transmits the rotational force to the said rear side gear. The electric actuator according to any one of the above. The electric actuator according to claim 5, wherein the intermediate gear (125) meshes with the rear-stage side gear to transmit a rotational force to the rear-stage gear. 7. The electric actuator according to claim 1, wherein the multi-pole magnet includes a pair of the N pole and the S pole arranged in a circumferential direction at a predetermined angle.

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