JP2018155528A - Rotational angle detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotational angle detector which can be manufactured at lower cost, can have increased detection accuracy by becoming less affected by use environments, can be downsized by a simple configuration, and is free of long-term deterioration due to abrasion.SOLUTION: A rotational angle detector includes: a sector gear 17 (driven side gear); a pinion 19 (driving side gear) connected to the sector gear 17 by a gear coupling part; a driving motor 12 having an output shaft 12a connected to the pinion 19; a vibration pick-up 21 fixed to the sector gear 17, the vibration pick-up detecting vibration of the sector gear 17; and a signal processing circuit for determining a current opening (a rotational angle of the sector gear 17) on the basis of magnitude of the vibration detected by the vibration pick-up 21.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a rotation angle detection device that detects a rotation angle of a rotating member.

  2. Description of the Related Art Conventionally, for example, a rotary actuator that drives an air conditioning valve has a rotation angle detection device that detects a rotation angle of a rotation shaft. Many conventional rotation angle detection devices of this type use a potentiometer whose electric resistance changes according to the rotation angle, a magnetic sensor whose magnetic flux density changes according to the rotation angle, and the like.

In the air conditioning valve, the rotation angle detection device that detects the rotation angle of the rotation shaft greatly affects the control accuracy of the actuator. For this reason, in recent air conditioning valves, it is required to further increase the detection accuracy of the rotation angle detection device so that the opening degree can be controlled with higher accuracy.
In order to make detection accuracy higher than that of a rotation angle detection device using a potentiometer, a magnetic sensor, or the like, it is conceivable to use a measurement device as described in Patent Document 1, for example.
The measurement device disclosed in Patent Document 1 uses propagation of surface acoustic waves on a substrate for position detection.

JP 2011-257315 A

  However, the measuring device described in Patent Document 1 is greatly affected by heat and changes in accuracy. On the other hand, the temperature of the air conditioning valve changes greatly due to the heat of the drive motor and the heat of the control fluid flowing in the valve. For this reason, in order to apply the measuring device shown in Patent Document 1 to the rotary actuator of the air conditioning valve, the temperature characteristics cannot be maintained unless the base material of the measuring device is made of a material having a small coefficient of thermal expansion. Since such a base material is expensive, when this measuring device is used as an actuator for an air conditioning valve, the manufacturing cost of the air conditioning valve increases.

  Further, the surface acoustic wave sensor used in the measuring device of Patent Document 1 is also used for a humidity sensor, and is generally known to be greatly affected by humidity. For this reason, with this measuring device, it is difficult to accurately measure the opening of the air conditioning valve installed in a humidity environment where the relative humidity is 5 to 95 RH.

  Furthermore, in order to incorporate the measuring device disclosed in Patent Document 1 into an actuator for an air conditioning valve, the number of parts increases as described below, and the actuator becomes complicated due to structural and design restrictions. At the same time, there is a problem of increasing the size. There are two reasons why the number of parts increases. The first reason is that a base material for propagating surface acoustic waves is required separately from the actuator parts. The second reason is that a mechanism for interlocking the receiver and the actuator is necessary so that the receiver of the measuring device moves in the rotation direction of the actuator.

The structural restriction is that the propagation direction of the surface acoustic wave generated from the exciter must be configured to coincide with the rotation direction of the actuator, and the receiver must be arranged along this direction.
A design limitation is that the exciter and receiver must be installed on the same surface.
In addition, the receiver of the measuring device shown in Patent Document 1 slides in contact with the scale substrate. For this reason, this measuring device has a problem that the contact portion between the receiver and the scale substrate is worn and deteriorated when used for a long period of time.

  The present invention has been made in order to solve such problems. The manufacturing cost is low, and the detection accuracy is improved because the manufacturing cost is low, and the detection accuracy is improved. An object of the present invention is to provide a rotation angle detection device that is free from deterioration over time.

  A rotation angle detection device according to the present invention includes a driven gear that rotates to detect a rotation angle, a driving gear connected to the driven gear via a gear coupling portion, and a coupling to the driving gear. A motor having an output shaft, a vibration pickup fixed to the driven gear and detecting vibration of the driven gear, and rotation of the driven gear based on the magnitude of vibration detected by the vibration pickup And a signal processing circuit for obtaining an angle.

  In the rotation angle detection device according to the present invention, the driven gear, the drive gear, and the motor may constitute a drive system of a rotary actuator.

  In the rotation angle detection device according to the present invention, the signal processing circuit may include a storage unit that stores a rotation angle of the driven gear when the motor is stopped.

  According to the present invention, the vibration of the motor is transmitted from the output shaft to the vibration pickup via the drive side gear and the driven side gear. The vibration of the motor detected by the vibration pickup is attenuated according to the distance between the motor and the vibration pickup. This vibration is strong when the distance between the motor and the vibration pickup is short, and is weak when this distance is long. The distance between the motor and the vibration pickup corresponds to the magnitude of the rotation angle of the driven gear. For this reason, according to this rotation angle detection device, the rotation angle of the driven gear can be obtained based on the magnitude (strength) of this vibration.

  This rotation angle detection device is constituted by a driven gear, a drive gear, a motor, a vibration pickup, and a signal processing circuit, and has a simple structure realized with a small number of components. For this reason, according to this rotation angle detection apparatus, compared with the measuring apparatus shown in patent document 1, a manufacturing cost can be suppressed low. The vibration pickup used in this rotation angle detection device is less susceptible to the influence of temperature and humidity than a sensor using surface acoustic waves, and a commercially available inexpensive pickup can be used. This also reduces the cost.

The magnitude (intensity) of vibration transmitted from the motor to the vibration pickup does not change greatly even if the temperature or humidity changes. For this reason, it is difficult to be influenced by the use environment, and the detection accuracy is increased.
In addition, the position where the vibration pickup is fixed to the driven gear does not need to consider the direction in which the vibration is propagated, and any position where the distance from the motor changes as the driven gear rotates. It may be a position. Moreover, the material of the driven gear to which the vibration pickup is attached is not particularly limited as long as it is a rigid body. For this reason, the degree of freedom is high in designing the rotation angle detection device.

As a result, the vibration pickup can be arranged compactly with a simple mounting structure so as to follow the driven gear.
Furthermore, since the vibration source is a motor and the vibration pickup is fixed to the driven gear, the vibration pickup does not contact the rotating member, and wear does not occur when detecting the rotation angle.

  Therefore, according to the present invention, a rotation angle detection device that is low in manufacturing cost and has a high detection accuracy while adopting a configuration that is not easily affected by the use environment, and that can be downsized with a simple configuration and is free from deterioration due to wear. Can be provided.

It is a perspective view which fractures | ruptures and shows the valve body of the valve | bulb for air conditioning provided with the rotation angle detection apparatus which concerns on this invention. It is a perspective view which shows the structure of a rotation angle detection apparatus. It is a top view of a part of transmission mechanism in a fully closed state, a motor, and a vibration pickup. It is a top view of a part of transmission mechanism in a fully open state, a motor, and a vibration pickup. It is a block diagram which shows the structure of a control system. It is a graph which shows the change of the magnitude of vibration when changing from a fully closed state to a fully opened state. It is a graph which shows the change of the magnitude of vibration when changing from a full open state to a full closed state.

Hereinafter, an embodiment of a rotation angle detection device according to the present invention will be described in detail with reference to FIGS.
A rotation angle detection device 1 shown in FIG. 1 is installed in an actuator 3 that drives an air conditioning valve 2. The air conditioning valve 2 is configured by assembling a valve body 5 and a valve stem 6 to a valve body 4. A fluid passage 7 is formed inside the valve body 4. Mounting flanges 8 are provided at both ends of the valve body 4.

The valve body 5 is formed in a spherical shape and is disposed in the fluid passage 7 and is rotatably supported by the valve body 4.
The valve stem 6 is formed in a columnar shape, and is rotatably supported by the valve body 4 with one end projecting from the valve body 4. One end of the valve stem 6 is connected to the actuator 3. The other end of the valve stem 6 is connected to the valve body 5 so as to rotate integrally. For this reason, the valve body 5 rotates around the axis C of the valve stem 6. The maximum rotation angle when the valve body 5 rotates is about 90 °. In the air conditioning valve 2 according to this embodiment, when the valve body 5 is rotated about 90 ° from the fully open state, the valve body 5 is fully closed, and the valve body 5 is rotated about 90 ° in the opposite direction from the fully closed state. To return to the fully open state.

The actuator 3 is a rotating type that rotates the valve body 5, and includes a housing 11 supported by the valve body 4, a driving motor 12 and a valve control device 13 housed in the housing 11, and the like. It has.
The drive motor 12 serves as a power source for driving the air conditioning valve 2, and is connected to the valve stem 6 via the transmission mechanism 14. In this embodiment, this driving motor corresponds to the “motor” in the present invention. This drive motor is supported by the housing 11 via a bracket (not shown).
The transmission mechanism 14 constitutes a drive system for the rotary actuator 3, and includes a rotary shaft 16 connected to the valve stem 6 via a joint 15, a sector gear 17 fixed to the rotary shaft 16, A pinion 19 connected to the sector gear 17 via a gear coupling 18 is formed.

As shown in FIG. 2, the sector gear 17 includes a boss portion 17a through which the rotary shaft 16 passes, and a plate-like gear portion 17b that protrudes radially outward from the boss portion 17a. The gear portion 17 b is formed in a fan shape when viewed from the axial direction of the rotating shaft 16. Teeth 17c are formed on the peripheral wall portion of the gear portion 17b.
A vibration pickup 21 described later is fixed to the gear portion 17 b of the sector gear 17. The position where the vibration pickup 21 is attached is one end surface in the axial direction of the gear portion 17 b and one end portion in the rotation direction of the sector gear 17.

  The gear coupling portion 18 is a portion where the sector gear 17 and the pinion 19 mesh with each other in this embodiment. Although not shown, when a plurality of intermediate gears are provided between the sector gear 17 and the pinion 18 in order to increase the reduction ratio, the power transmission unit using these intermediate gears is connected to the gear coupling unit 18. Become.

The pinion 19 is fixed to the output shaft 12a (see FIG. 2) of the drive motor 12. Therefore, when the drive motor 12 rotates, the rotational force is transmitted from the pinion 19 to the sector gear 17 through the gear coupling portion 18, and the rotating shaft 16 rotates integrally with the valve stem 6 and the valve body 5.
The sector gear 17 and the pinion 19 according to this embodiment are made of a plastic material. Further, the meshing rate of the sector gear 17 and the pinion 19 is 1.0 or more. That is, these gears are meshed with teeth always in contact.

  In this transmission mechanism 14, the sector gear 17 moves from the fully closed position shown in FIG. 3 by shifting from the fully closed state where the opening degree of the air conditioning valve 2 is 0% to the fully open state where the opening degree is 100%. In the same figure, it is rotated about 90 ° in the clockwise direction and is located at the fully open position shown in FIG. In this embodiment, the sector gear 17 corresponds to the “driven gear” in the present invention, and the pinion 18 corresponds to the “drive gear” in the present invention.

  The valve control device 13 controls the operation of the drive motor 12 so that the current opening degree of the air conditioning valve 2 becomes the target opening degree. As shown in FIG. 5, the valve control device 13 is connected to the drive motor 12 and the vibration pickup 21 and has a plurality of functional units. The plurality of functional units are a communication unit 22, a motor control unit 23, and an opening degree detection unit 24, details of which will be described later.

The current opening degree of the air conditioning valve 2 is detected by a rotation angle detection device 1 having a drive motor 12 and a vibration pickup 21. The description of the rotation angle detection device 1 will be described later.
The target opening degree of the air conditioning valve 2 is set by an air conditioning control device (not shown), and is sent as a control signal from the air conditioning control device to the valve control device 13.

  The drive motor 12 vibrates when operating. The vibration when the drive motor 12 operates is transmitted from the output shaft 12a to the sector gear 17 through the pinion 19 and the meshing portion (gear coupling portion 18) between the pinion 19 and the sector gear 17. That is, the vibration of the drive motor 12 is transmitted to the vibration pickup 21 through a vibration transmission path of the output shaft 12a → pinion 19 → sector gear 17. For this reason, the sector gear 17 is rotated between the fully closed position shown in FIG. 3 and the fully opened position shown in FIG. 4 while vibration is transmitted from the portion engaged with the pinion 19 and vibrates.

  As the vibration pickup 21 connected to the valve control device 13, for example, an acceleration sensor (not shown) that converts vibration into an electrical signal can be used. The vibration pickup 21 is fixed to the gear portion 21b of the sector gear 17 by a fixing screw or an adhesive (not shown). For this reason, the vibration pickup 21 detects the vibration of the gear portion 21 b of the sector gear 17.

  As shown in FIG. 3, the position where the vibration pickup 21 is fixed in the gear portion 21 b is a position separated from the position where the pinion 19 is engaged in the rotation direction of the sector gear 17. The vibration pickup 21 according to this embodiment is one end portion in the rotation direction of the sector gear 17 and proceeds when the sector gear 17 rotates in the direction in which the opening degree of the air conditioning valve 2 increases (clockwise in FIG. 3). It arrange | positions at the one end part of the sector gear 17 used as a direction back side. For this reason, the distance between the vibration pickup 21 and the drive motor 12 is gradually shortened as the sector gear 17 rotates from the fully closed position shown in FIG. 3 to the fully opened position shown in FIG. It becomes longer gradually by turning from the position to the fully closed position.

The communication unit 22 provided in the valve control device 13 has a function of receiving a control signal from an air conditioning control device (not shown). This control signal includes target opening data.
The motor control unit 23 has a function of switching the normal rotation and reverse rotation of the drive motor 12 and controlling the operation of the rotary actuator 3 by switching the rotation and stop of the drive motor 12.

The opening degree detection unit 24 constitutes a part of the rotation angle detection device 1 and is provided as a signal processing circuit 25 in the valve control device 13. The rotation angle detection device 1 according to this embodiment includes the signal processing circuit 25, the sector gear 17, the drive motor 12 having the pinion 19, the vibration pickup 21, and the like.
The opening degree detection unit 24 has first to fourth functions. The first function is a function for obtaining the current opening degree of the air conditioning valve 2 based on the magnitude of vibration detected by the vibration pickup 21 described above.

  The vibration pickup 21 detects a vibration wave transmitted from the drive motor 12 via the pinion 19 and the sector gear 17. The vibration detected by the vibration pickup 21 is attenuated according to the distance between the drive motor 12 and the vibration pickup 21. This vibration is strong when the distance between the driving motor 12 and the vibration pickup 21 is short, and is weak when this distance is long. For this reason, the magnitude of vibration detected by the vibration pickup 21 corresponds to the magnitude of the rotation angle of the sector gear 17.

  In this embodiment, the vibration detected by the vibration pickup 21 is the smallest (weak) when the sector gear 17 is in the fully closed position shown in FIG. 3, and the largest when the sector gear 17 is in the fully opened position shown in FIG. Become stronger. The vibration detected by the vibration pickup 21 when the sector gear 17 rotates from about 0 ° in the fully closed position to about 90 ° in the fully open position gradually increases as shown in FIG. The vibration detected by the vibration pickup 21 when the sector gear 17 rotates from the fully open position to the fully closed position gradually decreases as shown in FIG.

  When the opening degree detection unit 24 obtains the current opening degree, for example, the opening degree corresponding to the current magnitude of vibration detected by the vibration pickup 21 is read from a data map (not shown) for opening degree determination. Can be done. In this data map, data obtained by experiments conducted using the vibration pickup 21 is recorded. This data is the magnitude of the vibration during the experiment and the opening when the vibration is detected. For this reason, the current opening degree obtained by the opening degree detection unit 24 is the opening degree during the experiment corresponding to the current magnitude of vibration.

  A second function of the opening degree detection unit 24 is a function of removing unnecessary vibrations from vibrations detected by the vibration pickup 21. Unnecessary vibration is vibration generated at the meshing portion of the sector gear 17 and the small-diameter gear 22 or vibration transmitted from the valve body 4. This second function can be realized by performing correction processing such as noise cut and averaging processing on the output data of the vibration pickup 21.

The third function of the opening degree detection unit 24 is a function of storing the opening degree of the air conditioning valve 2 corresponding to the rotation angle of the sector gear 17 when the driving motor 12 is stopped. This storage is performed by storing the opening when the motor is stopped in the memory 26 provided in the opening detector 24. In this embodiment, the memory 26 corresponds to a “storage unit” in the invention described in claim 3.
By storing the opening when the motor is stopped in this way, even if the target opening is changed during the period when the drive motor 12 is stopped, the opening at the time of stopping read from the memory 26 is the current value. It becomes possible to control the operation of the drive motor 12 instead of the opening.

  In addition, when the power of the rotary actuator 3 is cut off, the opening degree detection unit 24 is configured to perform calibration when the rotary actuator 3 is restarted next time. That is, the opening degree detection unit 24 obtains a correction value so that the current data detected by the vibration pickup 21 after restart and the data recorded in the above-described data map are matched, The current opening is detected by correcting with the correction value. For this reason, for example, even if maintenance is performed and the magnitude of vibration detected by the vibration pickup 21 changes, the current opening degree can be detected with initial detection accuracy.

  A fourth function of the opening degree detection unit 24 is a function of detecting an abnormality in the drive motor 12 and the transmission mechanism 14. When an abnormality occurs in the drive motor 12 or the transmission mechanism 14, it appears as vibration. By detecting vibration caused by such an abnormality, it is possible to determine the presence or absence of the abnormality. The opening degree detection unit 24 analyzes the frequency component of the vibration included in the detection data of the vibration pickup 21 and determines that there is an abnormality when the vibration of the frequency component corresponding to the abnormal vibration is detected.

In the air conditioning valve 2 configured as described above, the operation of the drive motor 12 is controlled by the valve control device 13 so that the current opening obtained by the rotation angle detection device 1 matches the target opening. The
The rotation angle detection device 1 according to this embodiment includes a sector gear 17, a pinion 19, a drive motor 12, a vibration pickup 21, and a signal processing circuit 25, and is realized with a small number of components. It has a simple structure. For this reason, according to this rotation angle detection apparatus 1, compared with the measuring apparatus shown in patent document 1, a manufacturing cost can be suppressed low.

The drive motor 12 and the vibration pickup 21 used in the rotation angle detection device 1 are less susceptible to temperature and humidity than a sensor using surface acoustic waves, and both are inexpensive that are commercially available. Things can be used. This also reduces the cost.
The magnitude (intensity) of vibration transmitted from the drive motor 12 to the vibration pickup 21 does not change greatly even if the temperature and humidity change. For this reason, it is difficult to be influenced by the use environment, and the detection accuracy is increased.

  Further, the position where the vibration pickup 21 is fixed to the sector gear 17 does not need to consider the direction in which vibration is propagated, and may be a position where the distance from the drive motor 12 changes as the sector gear 17 rotates. Any position is acceptable. Moreover, the material forming the sector gear 17 is not particularly limited as long as it is a rigid body. For this reason, the degree of freedom is high in designing the rotation angle detection device 1. As a result, the vibration pickup 21 can be arranged compactly with a simple mounting structure along the sector gear 17.

Furthermore, since the vibration pickup 21 is fixed to the sector gear 17, it does not come into contact with the rotating member, and wear does not occur when detecting the rotation angle.
Therefore, according to this embodiment, the manufacturing cost is low, the detection accuracy is improved because it is not easily affected by the use environment, and the rotation angle detection that can be downsized with a simple configuration and does not deteriorate over time due to wear. An apparatus can be provided.

  The sector gear 17 and the drive motor 12 having the pinion 19 according to this embodiment constitute a part of the drive system of the rotary actuator 3. The vibration pickup 21 is fixed to the gear portion 17 b of the sector gear 17. According to this embodiment, when detecting the vibration with the vibration pickup 21, a component for transmitting the vibration exclusively is unnecessary. For this reason, compared with the case where the dedicated component for vibration transmission is used, the number of components is reduced, the manufacturing cost is further reduced, and further downsizing is possible.

The signal processing circuit 24 according to this embodiment includes a memory 26 (storage unit) that stores the opening degree of the air conditioning valve corresponding to the rotation angle of the sector gear 17 when the drive motor 12 is stopped.
For this reason, even when the drive motor 12 is stopped and no vibration is generated, the current opening degree (rotation angle) stored in the memory 26 can be substituted for the current opening. The degree (current rotation angle) can be detected. Therefore, since the opening degree (rotation angle) can always be detected, it is possible to provide a rotation angle detection device with high reliability of the detection value.

The rotation angle detection device 1 according to this embodiment uses the current opening degree as the opening degree during the experiment corresponding to the current magnitude of vibration. For this reason, when installing the vibration pickup 21, it is not necessary to perform precise positioning.
The vibration pickup 21 can detect not only vibrations transmitted on the surface but also vibration waves transmitted in the substance. For this reason, the position where the vibration pickup 21 is fixed to the sector gear 17 is not limited to the position shown in FIG. 3 and can be changed as appropriate. For example, the vibration pickup 21 can be disposed on the lower surface side of the sector gear 17 below the paper surface in FIG. 3, or can be fixed to the boss portion 17 a of the sector gear 17.

  In the above-described embodiment, an example in which the sector gear 17 and the pinion 19 that transmit vibration are formed of a plastic material has been described. However, the sector gear 17 and the pinion 19 can be formed of a metal material. Further, when an intermediate gear is used as the gear coupling portion 18, an intermediate gear formed of the same material as the sector gear 17 and the pinion 19 can be used.

  DESCRIPTION OF SYMBOLS 1 ... Rotation angle detection apparatus, 3 ... Rotary actuator, 12 ... Drive motor, 12a ... Output shaft, 17 ... Sector gear (driven side gear), 18 ... Gear coupling part, 19 ... Pinion (driven side gear), 21... Vibration pickup, 24... Signal processing circuit, 26.

Claims (3)

A rotating driven gear for detecting a rotation angle;
A drive side gear connected to the driven side gear via a gear coupling;
A motor having an output shaft coupled to the drive side gear;
A vibration pickup fixed to the driven gear and detecting vibration of the driven gear;
And a signal processing circuit for obtaining a rotation angle of the driven gear based on the magnitude of vibration detected by the vibration pickup. The rotation angle detection device according to claim 1,
The rotation angle detecting device, wherein the driven gear, the driving gear, and the motor constitute a driving system of a rotary actuator. In the rotation angle detection device according to claim 1 or 2,
The signal processing circuit includes a storage unit that stores a rotation angle of the driven gear when the motor is stopped.

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