JP2011196869A - Linear and rotary encoder, linear and rotary motor and linear and rotary motor system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a linear and rotary encoder capable of measuring a rotary position and a linear position of a detection object and being miniaturized and reducing manufacture cost, and to provide a linear and rotary motor and a linear and rotary motor system.SOLUTION: The linear and rotary encoder 100 has: a linear and rotary part 110 capable of being rotated around a drive shaft AX, and following rotary and linear movement of a linear movable detection object 21; a ring-like track T provided on a surface 111 of the linear and rotary part, having a constant distance up to the drive shaft, and having a shape changed in one or more cycles within one rotation of the linear and rotary part with a position of a drive shaft direction; detecting parts S1-S4 fixed and arranged by facing the track respectively and detecting detection signals G1-G4 corresponding to distances L1-L4 along the drive shaft up to the track; and a position specifying part 120 for specifying a linear position of the drive shaft direction of the detection object and a rotary position around the drive shaft on the basis of the detection signals.

Description

  The present invention relates to a linear motion rotary encoder, a linear motion rotation motor, and a linear motion rotation motor system.

An encoder is used to measure physical quantities such as the position and speed of the moving body.
This encoder is roughly classified into a rotary type (hereinafter also referred to as “rotary”) and a linear type (hereinafter also referred to as “linear”) according to the moving direction of the moving body.

  The rotary encoder is also referred to as a rotational position detection device or the like. For example, as shown in Patent Document 1, the rotary encoder detects the position (angle), speed (rotational speed), and the like of a moving body (rotating body). On the other hand, the linear encoder is also referred to as a linear position detection device or the like, and detects the position (linear position), speed, and the like of a moving body as shown in Patent Document 2, for example.

Japanese Patent No. 2977821 JP-A-8-193843

  On the other hand, in recent years, devices that move not only in a linear or rotational uniaxial direction but also in multiple axes including linear and rotational have been developed. Linear movement is also referred to as “linear motion”, and a motor that moves a moving body in multiple axes including linear motion and rotation is also referred to as “linear motion rotation motor”. In a linear motion rotary motor, it may be necessary to measure the position of the moving body in order to control the position of the moving body.

  In this case, for example, both the rotary encoder and the linear encoder are often separately connected in series or in parallel to the shaft of the direct rotation motor to measure both the rotational position and the linear position.

  However, if at least two different types of encoders are arranged in this way, the configuration of the apparatus itself becomes large and the manufacturing cost of the apparatus increases.

  Therefore, the present invention has been made in view of such problems, and an object of the present invention is to be able to measure the rotational position and linear position of the detection target, and to reduce the size and It is an object of the present invention to provide a linear motion rotary encoder, a linear motion rotary motor, and a linear motion rotary motor system capable of reducing manufacturing costs.

In order to solve the above-described problem, according to an aspect of the present invention, the detection target is formed to be connectable to a detection target that is rotatable around one drive shaft and is linearly movable along the drive shaft. A linear motion rotating part capable of rotating and moving linearly following the rotation and linear movement of
A shape that is provided on the surface in the drive shaft direction of the linear motion rotating portion, has a constant distance to the drive shaft, and changes in position in the drive shaft direction for one cycle or more within one rotation of the linear motion rotating portion. One or more ring-shaped tracks having
Two or more detection units that are respectively fixedly disposed to face the one or more tracks, and that respectively detect detection signals according to the distance along the drive axis to the one track facing the track,
A position specifying unit that specifies a linear position of the detection target in the direction of the drive axis and a rotational position around the drive axis based on the two or more detection signals detected by the two or more detection units;
A linear motion rotary encoder is provided.

Further, the surface in the drive shaft direction in the linear motion rotating part is a planar measurement surface inclined by a predetermined angle from a surface perpendicular to the drive shaft,
The one track may be formed on the measurement surface.

In addition, each of the two or more detection units detects the detection signal by irradiating irradiation light to the opposed one track and receiving reflected light from the track,
The one opposed track may have a reflection shape that increases the amount of light reflected toward the one opposed detection unit.

  Further, the one opposed track may have a substantially V-shaped groove formed over the entire circumference of the ring as the reflective shape.

  Further, at least one of the tracks may be formed in a shape in which a position in the drive axis direction changes linearly with respect to an angle around the measurement axis except an inflection point.

  In addition, the measurement surface of the at least one track has one end connected to the detection target and the other end of a shaft extended along the drive shaft is cut at a predetermined angle with respect to the drive shaft. It may be a cut surface.

In order to solve the above-described problem, according to another aspect of the present invention, a shaft to which a detection target can be connected at one end can be rotated around a drive shaft formed by extending the shaft, and the drive shaft A linear motion motor that can move linearly along
A linear motion rotating part fixed to the other end of the shaft and capable of rotating and linearly moving following the rotation and linear movement of the detection target;
A shape that is provided on the surface in the drive shaft direction of the linear motion rotating portion, has a constant distance to the drive shaft, and changes in position in the drive shaft direction for one cycle or more within one rotation of the linear motion rotating portion. One or more ring-shaped tracks having
Two or more detection units that are respectively fixedly disposed to face the one or more tracks, and that respectively detect detection signals according to the distance along the drive axis to the one track facing the track,
A position specifying unit that specifies a linear position of the detection target in the direction of the drive axis and a rotational position around the drive axis based on the two or more detection signals detected by the two or more detection units;
A linear motion rotary motor is provided.

In order to solve the above-described problem, according to another aspect of the present invention, a shaft to which a detection target can be connected at one end can be rotated around a drive shaft formed by extending the shaft, and the drive shaft A linear motion motor that can move linearly along
A linear motion rotating part fixed to the other end of the shaft and capable of rotating and linearly moving following the rotation and linear movement of the detection target;
A shape that is provided on the surface in the drive shaft direction of the linear motion rotating portion, has a constant distance to the drive shaft, and changes in position in the drive shaft direction for one cycle or more within one rotation of the linear motion rotating portion. One or more ring-shaped tracks having
Two or more detection units that are respectively fixedly disposed to face the one or more tracks, and that respectively detect detection signals according to the distance along the drive axis to the one track facing the track,
A position specifying unit that specifies a linear position of the detection target in the direction of the drive axis and a rotational position around the drive axis based on the two or more detection signals detected by the two or more detection units;
A control unit for controlling the linear motion rotary motor unit based on the linear position and the rotational position of the detection target specified by the position specifying unit;
A linear motion rotary motor system is provided.

  As described above, according to the present invention, it is possible to measure the rotational position and the linear position of the detection target, and it is possible to reduce the size and the manufacturing cost.

It is explanatory drawing for demonstrating the structure of the linear motion rotary motor system which concerns on 1st Embodiment of this invention. It is explanatory drawing for demonstrating the structure of the linear motion rotary encoder which concerns on the same embodiment. It is explanatory drawing for demonstrating the structure of the linear motion rotary encoder which concerns on the same embodiment. It is explanatory drawing for demonstrating the detection operation | movement in the linear motion rotary encoder which concerns on the same embodiment. It is explanatory drawing for demonstrating the detection operation | movement in the linear motion rotary encoder which concerns on the same embodiment. It is explanatory drawing for demonstrating the detection operation | movement in the linear motion rotary encoder which concerns on the same embodiment. It is explanatory drawing for demonstrating the detection operation | movement in the linear motion rotary encoder which concerns on the same embodiment. It is explanatory drawing for demonstrating an example of the detection process in the linear motion rotary encoder which concerns on the same embodiment. It is explanatory drawing for demonstrating an example of the detection process in the linear motion rotary encoder which concerns on the same embodiment. It is explanatory drawing for demonstrating an example of the track | truck which the linear motion rotary encoder which concerns on the same embodiment has. It is explanatory drawing for demonstrating the example of a change of the track | truck which the linear motion rotary encoder which concerns on the same embodiment has. It is explanatory drawing for demonstrating the track | truck which the linear motion rotary encoder which concerns on 2nd Embodiment of this invention has. It is explanatory drawing for demonstrating the track | truck which the linear motion rotary encoder which concerns on the same embodiment has. It is explanatory drawing for demonstrating the track | truck which the linear motion rotary encoder which concerns on the same embodiment has.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In this specification and the drawings, components having substantially the same function are denoted by the same reference numerals in principle, and redundant description of these components will be omitted as appropriate.

  In each embodiment of the present invention described below, a linear motion rotary motor system having a linear motion rotary encoder will be described as an example. That is, the linear motion rotary encoder according to each embodiment is applied to a linear motion rotary motor, and detects the rotational angle (also referred to as “rotational position θ”) and the linear position z of the linear motion rotary motor. However, the linear motion rotary encoder according to each embodiment described here is not limited to such a linear motion rotary motor or linear motion rotary motor system, but also a rotational position θ and a straight line of a moving body that performs linear motion and rotation. It may be used to detect the position z.

It should be noted that each embodiment of the present invention will be described in the following order so as to facilitate understanding.
<1. First Embodiment>
(1-1. Direct Acting Rotation Motor System According to First Embodiment)
(1-2. Configuration of linear motion rotary encoder according to the first embodiment)
(1-3. Detection Operation in Linear Motion Rotating Encoder According to First Embodiment)
(1-4. An example of detection processing in the linear motion rotary encoder according to the first embodiment)
(1-5. Example of track included in linear motion rotary encoder according to first embodiment)
(1-6. Examples of effects by linear motion rotary motor system and the like according to first embodiment)
Second Embodiment
(2-1. Configuration of linear motion rotary encoder according to the second embodiment)
(2-2. Examples of effects by linear motion rotary motor system and the like according to the second embodiment)

<1. First Embodiment>
(1-1. Direct Acting Rotation Motor System According to First Embodiment)
First, the configuration of a direct acting rotation motor system according to the first embodiment of the present invention will be described with reference to FIG. FIG. 1 is an explanatory diagram for explaining a configuration of a direct acting rotation motor system according to the first embodiment of the present invention.

  As shown in FIG. 1, a direct acting rotation motor system (hereinafter also simply referred to as “motor system”) 1 according to the present embodiment includes a direct acting rotation motor (hereinafter also simply referred to as “motor”) 30 and a control unit. 40. The motor 30 includes a linear motion rotary encoder (hereinafter also simply referred to as “encoder”) 100 and a linear motion rotary motor portion (hereinafter also simply referred to as “motor portion”) 20.

  The motor unit 20 is an example of a power generation source that does not include the encoder 100. The motor unit 20 may be simply referred to as a motor. The motor unit 20 has a shaft 21 on at least one side, and outputs a rotational force by rotating the shaft 21 around the drive axis AX. On the other hand, the motor unit 20 outputs direct power by sliding the shaft 21 in the direction of the drive axis AX. On the other hand, the shaft 21 is connected to an object to be driven (hereinafter, also referred to as a “detection object” in the sense of an object whose position is detected by the encoder 100 or a “moving object” in the meaning of an object to be moved. Formed possible. Here, for convenience of explanation, the shaft 21 is described as a detection target. Therefore, the motor unit 20 can rotate or linearly move the detection target by rotating or linearly moving (moving on a straight line) the shaft 21.

  As described above, here, the position in the rotational direction of the detection target driven by the motor unit 20 is also referred to as “rotational position θ”, and the position in the linear motion direction is also referred to as “linear position z”. The rotational position θ and the linear position z are collectively referred to simply as “position”, and data representing this position is collectively referred to herein as “position data”.

  The motor unit 20 is not particularly limited as long as it is a servo motor controlled based on position data. The motor unit 20 is not limited to an electric motor unit that uses electricity as a power source. For example, other power sources such as a hydraulic motor unit, an air motor unit, and a steam motor unit are used. It may be a motor part. However, for convenience of explanation, a case where the motor unit 20 is an electric motor unit will be described below. Furthermore, the motor unit 20 may be formed as a single motor, but may be a device in which the rotation motor and the linear motion motor output power via the same shaft 21. On the other hand, the detection target to be driven by the motor unit 20 is not particularly limited, and needless to say, it may be various targets as long as it is a target that requires at least one of linear motion and rotation. .

  The encoder 100 is disposed on the opposite side of the shaft 21 of the motor unit 20 and is connected to another shaft 22 that linearly moves and rotates in correspondence with the shaft 21. The encoder 100 detects the position of the shaft 22 to detect the position of the shaft 21 to which the rotational force and the direct power are output, that is, the position of the detection target, and outputs position data representing the position. . Here, the position or the like of the detection target is also referred to as the position or the like of the motor unit 20 for convenience of explanation.

  The encoder 100 may detect at least one of the speed (angular velocity and linear motion speed) and acceleration (angular acceleration and linear motion acceleration) of the shaft 21 in addition to or instead of the position of the motor unit 20. In this case, the speed and acceleration of the motor unit 20 can be detected by, for example, a process of differentiating the position once or twice with respect to time. For convenience of explanation, the following description assumes that the position may include velocity and acceleration, and the physical quantity detected by the encoder 100 is the position.

  The arrangement position of the encoder 100 is not particularly limited. For example, the encoder 100 may be disposed so as to be directly connected to the shaft 21 or may be connected to a detection target such as the shaft 21 via another mechanism such as a speed reducer or a rotation direction changer. .

  The control unit 40 acquires position data output from the encoder 100, and controls linear movement / rotation of the motor unit 20 based on the linear position z and the rotation position θ represented by the position data. Therefore, in this embodiment in which an electric motor unit is used as the motor unit 20, the control unit 40 controls the current or voltage applied to the motor unit 20 as a control signal based on the position data, thereby The linear movement / rotation of the unit 20 is controlled. Further, the control unit 40 acquires a high-order control signal from a high-order control device (not shown) so that the position or speed represented by the high-order control signal is output from the shaft 21 of the motor unit 20. It is also possible to control the motor unit 20. When the motor unit 20 uses other power sources such as a hydraulic type, an air type, a steam type, etc., the control unit 40 controls the supply of these power sources to directly connect the motor unit 20. It is possible to control movement and rotation.

(1-2. Configuration of linear motion rotary encoder according to the first embodiment)
Next, the configuration of the linear motion rotary encoder 100 according to the present embodiment will be described with reference to FIGS. 2 and 3. FIG.2 and FIG.3 is explanatory drawing for demonstrating the structure of the linear motion rotary encoder which concerns on this embodiment. FIG. 3 schematically shows a cross section taken along line BB of the linear motion rotary encoder 100 of FIG.

  As shown in FIG. 2, the encoder 100 includes a disk 110, detection units S <b> 1 to S <b> 4, and a position specifying unit 120. Hereinafter, each configuration will be sequentially described.

  The disk 110 is an example of a linear motion rotation unit, and is connected to a shaft 22 that can be driven (including rotation and linear motion) together with the shaft 21 that is a detection target. Therefore, the disk 110 can be rotated around the drive axis AX as described above and can be connected to a detection target that can move linearly along the drive axis AX, and follows the rotation and linear movement of the detection target. Rotation and drive are possible.

  In the disk 110 that is an example of the linear motion rotating portion in the present embodiment, one surface in the drive axis AX direction is set as the measurement surface 111, and the track T is set in the measurement surface 111. In the present embodiment, the case where the measurement surface 111 is set to the surface opposite to the motor unit 20 in the drive axis AX direction is illustrated. However, the measurement surface 111 may be set to a surface on the motor unit 20 side. However, in this case, detection units S1 to S4 described later are also arranged closer to the motor unit 20 than the disk 110 so as to be able to face the measurement surface 111.

  Here, the positional relationship between the disk 110 (that is, the measurement surface 111) and the shaft 22 (that is, the drive axis AX) will be described with reference to FIG. As shown in FIG. 3, the disk 110 has a planar shape, and is fixed to the shaft 22 so that the plane is inclined by a predetermined angle α from a plane perpendicular to the drive axis AX. Accordingly, the measurement surface 111 is similarly inclined at a predetermined angle α from the surface perpendicular to the drive axis AX. In addition, the measurement surface 111 in the present embodiment is an example of “a surface in the drive shaft direction in the linear motion rotating unit”.

  2 and 3 exemplify the case where the disk 110 has a substantially disk shape or a substantially elliptical plate shape. However, the disk 110 is merely an example of a linear motion rotating portion, and the linear motion rotating portion can be formed in various forms as long as the track T can be formed. Therefore, for example, a ring-shaped member capable of forming the track T without having the measurement surface 111 can be used. Next, the track T will be described.

  In the present embodiment, the track T is set on the measurement surface 111 of the disk 110 that is inclined with respect to the measurement axis AX as described above. As a result, the track T has the following shape. That is, the track T has a ring shape with a constant distance r to the measurement axis AX, as shown in FIG. On the other hand, since the disk 110 is fixed while being tilted by a predetermined angle α with respect to a plane perpendicular to the measurement axis AX, the track T has a position in the drive axis AX direction of 1 while the disk 110 rotates once. It has a shape that changes periodically.

  That is, in the state shown in FIG. 3, the track T at the left side in FIG. 3 is located at a distance difference ΔZ from the reference plane A where the detection units S1 to S4 described later are arranged. Yes. When the disk 110 rotates from this state, the track T at the left position in FIG. 3 approaches the reference plane A side according to the rotation angle. As a result, the track T at the left position in FIG. 3 has the same distance as the center position O from the reference plane A, and is positioned closer to the reference plane A than the center position O by a distance difference ΔZ. . Thereafter, when the disk 110 further rotates and makes one rotation from the state shown in FIG. 3, the track T reaches the position shown in FIG. Accordingly, the position of the track T in the drive axis AX direction changes by one period while the disk 110 rotates once.

  An example of the track T according to this embodiment will be described in detail later.

  The detectors S1 to S4 are fixedly arranged facing the track T. In the present embodiment, the detection units S1 to S4 are arranged on the same plane (reference plane A) perpendicular to the drive axis AX, and are arranged at regular intervals of 90 ° around the drive axis AX.

  This arrangement facilitates calculation of position data and manufacture of the apparatus itself. For example, the detection units S1 to S4 may not be arranged on the same plane or may be arranged at an angle different from 90 °. Needless to say. However, when the four detection units S1 to S4 are arranged, the detection unit S1 and the detection unit S3 are arranged point-symmetrically with respect to the drive axis AX as in the present embodiment, and the detection unit S2 and the detection unit S2 are detected. It is desirable that the portion S4 be arranged point-symmetrically. When the two detection units that are paired in this way are arranged point-symmetrically across the drive axis AX, the encoder 100 can facilitate the position data specifying process or reduce errors due to eccentricity or the like. is there.

  The detection units S1 to S4 are thus arranged to face the track T, and detect detection signals G1 to G4 corresponding to the distances L1 to L4 to the track T along the drive axis AX, respectively. For example, when the motor unit 20 linearly moves or rotates the detection target shaft 21, the shaft 22 linearly moves or rotates following that, but the disk 110 connected to the shaft 22 (an example of a linearly rotating unit). In this case, the linear movement or rotation follows this. As a result, the distances L1 to L4 between the track T formed on the disk 110 and the detection units S1 to S4 change according to linear movement or rotation. Therefore, the detection units S1 to S4 detect the detection signals G1 to G4 having values corresponding to the detection target linear position z and the rotational position θ.

  In the present embodiment, an optical distance meter or displacement meter is used as an example of the detection units S1 to S4 that detect the detection signals G1 to G4 corresponding to the distances L1 to L4. When this optical distance meter or displacement meter is used, the detectors S1 to S4 irradiate irradiation light along the drive axis AX toward the track T facing the detector. The irradiation light is reflected by the track T and then received by the detection units S1 to S4. And detection part S1-S4 produces | generates the detection signals G1-G4 according to distance L1-L4 by measuring the time from light irradiation to light reception. The detection units S1 to S4 are not limited to such optical distance meters or displacement meters. For example, detection signals G1 to G4 corresponding to the distances L1 to L4 can be detected, such as a magnetic sensor. Various devices can be used as long as they are simple detection devices. When an optical distance meter or displacement meter is used, the detection accuracy of the detection signals G1 to G4 can be improved. When a magnetic sensor is used, environmental resistance is improved. Is possible.

  Based on the four detection signals G1 to G4 detected by the four detection units S1 to S4, the position specifying unit 120 rotates the linear position z in the drive axis AX direction of the shaft 21 to be detected and the rotation about the drive axis AX. The position θ is specified. As described above, the detection signals G1 to G4 change according to the distances L1 to L4, while the distances L1 to L4 depend on the linear position z and the rotational position θ. Therefore, the position specifying unit 120 specifies the linear position z and the rotational position θ based on the correlation between the detection signals G1 to G4 and the linear position z and the rotational position θ. An example of the detection process in the position specifying unit 120 will be described later in detail.

(1-3. Detection Operation in Linear Motion Rotating Encoder According to First Embodiment)
Here, the detection operation in the linear motion rotary encoder according to the present embodiment will be described in detail with reference to FIGS. 4-7 is explanatory drawing for demonstrating the detection operation | movement in the linear motion rotary encoder which concerns on this embodiment. 4 and 5 show a state where the disk 110 is driven from the state of FIG. 3 shows a state where the rotation angle θ is 90 ° and the linear position z is z1, and FIG. 4 shows a state where the disk T has rotated from the state shown in FIG. FIG. 5 shows a state in which the disk T moves linearly from the state of FIG. 3 and the linear distance z becomes z2.

  In the state shown in FIG. 3 (θ = 90 °, z = z1), since the detection unit S1 has a distance L from the track T to L1, the detection signal G1 thereby becomes a value corresponding to the distance L1. Similarly, since the detection units S2 to S4 have distances L2 to L4 from the track T, respectively, the detection signals G2 to G4 obtained thereby have values corresponding to the distances L2 to G4 as shown in FIG. Become.

  When the disk 110 is rotated by −90 ° from the state of FIG. 3 to the state shown in FIG. 4 (θ = 0 °, z = z1), the distances L1 and L2 decrease, while the distances L3 and L4 increase. To do. As a result, the detection signals G1 and G2 from the detection units S1 and S2 change as the distances L1 and L2 decrease, while the detection signals G3 and G4 from the detection units S3 and S4 change to a distance L3 as shown in FIG. , L4 changes with the decrease. Therefore, the rotational position θ of the disk 110 can be specified from the combination of the increase and decrease of the detection signals G1 to G4.

  On the other hand, the disk 110 linearly moves from the state shown in FIG. 3 so as to approach the detectors S1 to S4 in the drive axis direction AX, resulting in the state shown in FIG. 5 (θ = 90 °, z = z2). In this case, the distances L1 to L4 all decrease. As a result, the detection signals G1 to G4 from the detection units S1 to S4 change as the distances L1 to L4 decrease, as shown in FIG. Therefore, the linear position z of the disk 110 can be specified from the increase or decrease of all the detection signals G1 to G4.

At this time, as shown in FIGS. 6 and 7, even if the disk 110 moves linearly, the combination of the detection signals G1 to G4 can uniquely represent the rotational position θ, and the disk 110 Even if it rotates, the center of each of the detection signals G1 to G4 that increase or decrease with the rotation can uniquely represent the linear position z. The encoder 100 according to this embodiment includes:
Using such correlation, it is possible to simultaneously specify the rotational position θ and the linear position z to be detected.

(1-4. An example of detection processing in the linear motion rotary encoder according to the first embodiment)
Next, an example of the detection process for realizing the detection operation described above will be described together with a specific configuration example of the position specifying unit 120 that performs the process, with reference to FIGS. 8 and 9 are explanatory diagrams for describing an example of detection processing in the linear motion rotary encoder according to the present embodiment.

  As illustrated in FIG. 8, the position specifying unit 120 includes calculation units 121 and 122, a rotation position calculation unit 123, and a linear motion position calculation unit 124.

  The calculation unit 121 obtains the detection signals G1 and G3 from the detection units S1 and S3 that are arranged symmetrically in pairs and performs a subtraction process. On the other hand, the calculation unit 122 obtains the detection signals G2 and G4 from the detection units S2 and S4 that are arranged symmetrically in pairs and performs a subtraction process. FIG. 9 shows both differential signals (G1-G3, G2-G4) obtained after the subtraction processing by both the subtraction units 121, 122. As can be seen from the change in the differential signal shown in FIG. 9, both differential signals do not depend on the linear position z, but become a pseudo sine wave signal of one cycle per rotation depending only on the rotational position θ. Therefore, it corresponds to an A phase signal and a B phase signal, respectively. And the rotational position calculation part 123 specifies rotational position (theta) using such both differential signals. That is, the position specifying unit 123 includes the calculation units 121 and 122 and the rotation position calculation unit 123, so that the rotation position θ can be specified by performing processing such as the following formula (1), for example. . Since both differential signals correspond to the A-phase signal and the B-phase signal, it goes without saying that the position specifying unit 123 can easily specify not only the rotation position θ but also the rotation direction.

  The linear motion position calculation unit 124 acquires detection signals G1 to G4 from all four detection units S1 to S4, and performs, for example, an addition process on all the detection signals G1 to G4. As shown in FIGS. 6 and 7, the detection signals G1 to G4 change according to the rotational position θ, but the addition signal of the detection signals G1 to G4 cancels out the information on the rotational position θ, and the linear position z will be expressed. Therefore, the linear motion position calculation unit 124 can specify the linear position z using such an addition signal. In other words, the position specifying unit 123 includes the linear motion position calculating unit 124, so that the linear position z can be specified by performing processing such as the following equation (2), for example. It is also possible to specify the straight line position z from the addition signal obtained by adding only the two detection signals by the two detection units arranged in a point-symmetric manner as a pair. However, when all four detection signals G1 to G4 are added and the addition signal is calculated as in the present embodiment, it is possible to reduce errors included in the detection signals G1 to G4.

  Note that the configuration example and processing example of the position specifying unit 120 described here are merely examples, and various modifications are possible as long as the position specifying process based on the above correlation and a configuration that realizes the position specifying process. Needless to say.

(1-5. Example of track included in linear motion rotary encoder according to first embodiment)
In the encoder 100 according to the present embodiment, as described above, the distance L1 from the detection units S1 to S4 to the track T is obtained by arranging the disk 110 at a predetermined angle α with respect to a plane perpendicular to the drive axis AX. The position is specified by utilizing that L4 changes according to rotation and linear motion. In order to obtain the detection signals G1 to G4 corresponding to the distances L1 to L4, an optical distance meter or a displacement meter is used in this embodiment. When an optical distance meter or displacement meter is used, the detection units S1 to S4 acquire the reflected light from the track T.

  Therefore, in such a case, it is desirable that the track T has a reflective shape that increases the amount of light reflected toward the opposing detection units S1 to S4. As the reflection shape, for example, when the surface where the track T of the measurement surface 111 of the disk T is set to be a rough surface is formed, and the amount of light increases on the track T of the measurement surface 111. For example, providing a groove, a protrusion, a step, or the like. Thus, an example of a reflection shape that increases the amount of light reflected will be described with reference to FIGS. 10-13 is explanatory drawing for demonstrating an example of the track | truck which the linear motion rotary encoder which concerns on this embodiment has.

  FIG. 10 shows a partial cross-sectional view of the disk 110 at the right end of FIG. As shown in FIG. 10, the track T has a V-shaped groove 112 as a reflective shape.

  The V-shaped groove 112 is formed over the entire circumference of the ring. The angle of the V-shaped track T is preferably set to be the same as the inclination angle α of the track T as shown in FIG. On the other hand, it is desirable that the detection units S <b> 1 to S <b> 4 align the center of the irradiation light with the center point of the V-shaped groove 112 and irradiate almost the entire area of the V-shaped groove 112 with parallel light.

  In this case, in the state shown in FIG. 10 (θ = 90 °), one side surface of the V-shaped groove 112 faces the detection unit S3, and similarly, the other side surface of the V-shaped groove 112 faces the detection unit S1. Will do. Therefore, since the reflected light reflected by these opposing surfaces reaches each detection part S1, S3, the reflected light quantity increases. On the other hand, in the state shown in FIG. 10, the reflected light with respect to the detection units S2 and S4 reaches the detection units S2 and S4 by being reflected by the V-shaped groove 112 a plurality of times. Accordingly, the amount of light reflected toward the detection units S2 and S4 similarly increases.

(1-6. Examples of effects by linear motion rotary motor system and the like according to first embodiment)
The encoder 100, the motor 30, and the motor system 1 according to the first embodiment of the present invention have been described above. According to the encoder 100 and the like, the rotational position θ and the linear position z of the shaft 21 to be detected can be measured by only one encoder 100. There is no need to provide. Accordingly, not only the encoder 100 but also the members of the motor 30 and the motor system 1 as a whole can be reduced to reduce the size, and the manufacturing cost can be reduced.

  Further, according to the encoder 100 according to the present embodiment, the track T is formed on the measurement surface 111 of one disk 110, and the disk 110 is disposed by being inclined from the plane perpendicular to the drive axis AX. Since the linear motion rotating part can be formed, the manufacturing is very easy. In addition, without using such a disk 110, for example, as shown in FIG. 11, it is possible to use the cross section of the shaft 22 itself as the measurement surface 111 and form the track T on the measurement surface 111. It is. That is, one end of the shaft 22 is directly or indirectly connected to the detection target (shaft 21) and is extended along the drive axis AX, but the other end of the shaft 22 is connected to the drive axis AX. And cut at a predetermined angle (90 ° -α). And this cut surface may be set to the measurement surface 111, and the track | truck T may be set on the measurement surface. When the measurement surface 111 and the track T are set in this way, the shaft 22 itself is an example of a linear motion rotating part, and the disk T can be omitted. Therefore, the manufacturing can be further facilitated and the cost can be further increased. It is possible to reduce.

  Furthermore, the encoder 100 according to the present embodiment includes a track T having a shape (for example, a V-shaped groove 112) that increases the amount of reflected light. Therefore, it is not necessary to be affected by noise due to stray light or the like, and it is not necessary to use a highly sensitive light receiving element for the detection units S1 to S4.

Second Embodiment
As described above, the encoder 100 and the like according to the first embodiment of the present invention have been described. However, in the encoder 100, since the measurement surface 111 of the disk 110 has a planar shape, the detection signals G1 to G4 are As shown in FIG. 6 etc., it changed in the form of a pseudo sine wave with respect to the change of the rotational position θ. However, the present invention is not limited to this example, and the track T can be formed so that the detection signals G1 to G4 change in a linear triangular wave shape with respect to the change in the rotational position θ.

  Therefore, in the following, an example in which triangular wave detection signals G1 to G4 are obtained will be described as a second embodiment with reference to FIGS. 12-14 is explanatory drawing for demonstrating the track | truck which the linear motion rotary encoder which concerns on 2nd Embodiment of this invention has.

(2-1. Configuration of linear motion rotary encoder according to the second embodiment)
The encoder according to the present embodiment includes a disk 210 and a measurement surface 211 instead of the disk 110 and the measurement surface 111. Other configurations of the encoder according to the present embodiment are configured in the same manner as in the first embodiment. Therefore, in the following, differences from the first embodiment will be mainly described in the present embodiment, and detailed description of overlapping portions will be omitted. Then, for example, the supplementary explanation will be given for the change that has occurred in the processing by the position specifying unit 120 or the like.

  The disk 210 included in the encoder according to the present embodiment is an example of a linear motion rotating unit, and has a substantially disc shape or a substantially elliptic shape connected to a shaft 22 (not shown), as in the first embodiment. Formed and inclined at a predetermined angle α from a plane perpendicular to the drive shaft AX. Then, one side surface of the disk 210 (a surface facing the detection units S1 to S4 (not shown)) is set as the measurement surface 211, and the ring-shaped position where the distance to the drive axis AX on the measurement surface 211 is equal. The track T is set to.

  However, unlike the flat disk 110 according to the first embodiment, the disk 210 (that is, the measurement surface 211) has a curved shape as shown in FIG. Accordingly, the track T itself as well as the measurement surface 211 has a curved shape from a two-dimensional ellipse.

  Here, for convenience, the positive z-axis direction in FIG. 12 is referred to as “up” and the negative direction is referred to as “down”. In the track T, the position farthest from the surface (reference plane A) on which the detection units S1 to S4 (not shown) are arranged, that is, the lowest point is referred to as the “lowermost PD”. The position closest to the surface on which S1 to S4 are arranged, that is, the point located at the top is referred to as “uppermost PU”. Further, two points between the first position P1 and the second position P2 in the track T are each referred to as an “intermediate portion PM”, and a straight line passing through the two intermediate portions PM is referred to as an “intermediate line LM”. Further, a straight line passing through the lowermost PD and the uppermost PU is referred to as an “inclined center line Lα” in the sense that it is a center line in a state where the disk 210 is tilted.

Here, the shape of the track T (that is, the disk 210 and the measurement surface 211) will be described.
As described above, the track T has a curved ring shape that is inclined by an angle α from a plane perpendicular to the drive axis AX. As a result, the track T is formed in a shape in which the position in the drive axis AX direction changes linearly with respect to the angle around the measurement axis AX except for the lowermost PD and the uppermost PU (an example of an inflection point).

The curved shape will be described in more detail.
Here, since the track T according to the present embodiment is formed with the inclined center line Lα in between, the shape of the half of the track T on the one side from the inclined center line Lα of the track T on the ring will be seen. . Then, the ring-shaped track T has a substantially elliptical shape with the same distance from the drive axis AX (that is, the shape of the track T according to the first embodiment, hereinafter also referred to as “basic ellipse”). It has a curved shape.

  That is, as shown in FIG. 12, the track T is curved with a gentle sine wave curve upward from the basic ellipse to the above-mentioned lowermost part PD to the intermediate part PM, and from the intermediate part PM. Between the uppermost PU, it has a shape curved downward with a gentle sine wave curve. That is, on one side of the track T, when the lowermost PD is 0 °, the intermediate portion PM is 180 °, the uppermost PU is 360 °, and the upper portion is positive, it is a sine wave of one cycle. The shape obtained by bending the basic ellipse with the amount of bending is the shape of the track T. Therefore, when compared with the track T of the first embodiment (see FIG. 2 and the like), the track T of the present embodiment is different from the track T of the first embodiment in the lowermost PD, the intermediate portion PM, and the uppermost PU. Although it is the same position, it is located above the track T of the first embodiment between the lowermost PD and the intermediate portion PM, and between the intermediate portion PM and the uppermost PU, the track of the first embodiment. It will be located below T.

  FIG. 13 shows the change of the position in the drive axis AX direction (that is, the position in the z-axis direction) of the track T according to this embodiment with respect to the angle φ (corresponding to the electrical angle) around the drive axis AX.

  In FIG. 13, the position of the track T of the present embodiment in the z-axis direction is represented by a line F2, and the position of the track T (reference ellipse) of the first embodiment in the z-axis direction is represented by a line F1. Further, the amount of bending (bending amount) from the reference ellipse (line F1) is represented by a line ΔF. In FIG. 13, the angle and position at the intermediate point PM are set to φ = 0 ° and z = 0 with respect to the intermediate point PM. The distance of the track T from the drive axis AX is r, and the positions of the lowermost PD and the uppermost PU are z = −Δz and z = Δz, respectively (Δz = r × tan α).

  As shown in FIG. 13, the track T of the first embodiment changes to a pseudo sine wave with respect to the angle φ as shown by a line F1. This line F1 can be expressed as the following formula (3).

  On the other hand, as described above, the track T according to the present embodiment is curved with a sinusoidal curvature amount (line ΔF) of one cycle on one side, that is, two cycles in one cycle. As a result, the track T according to the present embodiment changes linearly (triangular wave) with respect to the angle φ as shown by the line F2. The bending amount (line ΔF) can be expressed as in the following formula (4), and the line F2 of the track T according to the present embodiment can be expressed as in the following formula (5).

  Therefore, when the disk 210 is rotated, the detection signals G1 to G4 detected by the detection units S1 to S4 according to the distances L1 to L4 to the track T that change due to the rotation are as shown in FIG. Similar to the position of the track T, it has a triangular wave shape that changes linearly with respect to the rotational position θ. The position specifying unit 120 according to the subordinate embodiment can specify the rotational position θ and the linear position z by using the detection signals G1 to G4 that change linearly. Note that the position data generation process by the position specifying unit 120 is changed such that a process using a linear function divided into sections is performed instead of using the trigonometric law when calculating the rotational position θ. However, since it can be basically performed in the same manner as in the first embodiment, a detailed description thereof is omitted here.

(2-2. Examples of effects by linear motion rotary motor system and the like according to the second embodiment)
The encoder and the like according to the second embodiment of the present invention have been described above. According to the encoder and the like according to the second embodiment, it is possible to achieve the same operational effects as the encoder 100 and the like according to the first embodiment. Furthermore, according to the encoder or the like according to the present embodiment, the detection signals G1 to G4 can be linearly changed with respect to the rotational position θ, so that the position data generation process can be made easier. .

  Note that when detecting the detection signals G1 to G4 of the pseudo sine wave as in the first embodiment, due to various factors, low-cycle and high-cycle noises different from the cycle of the detection signals G1 to G4 are detected signal G1. ~ G4 may be included. On the other hand, when detecting the detection signals G1 to G4 that change linearly as in the present embodiment, the possibility of including low-cycle and high-cycle noise is reduced, and even if included, noise is easily generated. It can be removed. Therefore, according to the encoder and the like according to the present embodiment, it is possible to further improve the position specifying accuracy.

  The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, it goes without saying that the present invention is not limited to the examples of these embodiments. It is obvious that a person having ordinary knowledge in the technical field to which the present invention pertains can make various changes and modifications within the scope of the technical idea described in the claims. Accordingly, the technology after these changes and corrections naturally belong to the technical scope of the present invention.

  For example, in the above-described embodiment, the case where the four detection units S1 to S4 are arranged and the position data is generated from the four detection signals G1 to G4 has been described. However, the number of detection units according to this embodiment may be two or more. When the two detection units are arranged, one detection unit is arranged at a position on the reference plane A where the distance to the track T is the shortest and a farthest position on the reference surface A in a state where the rotational position θ is constant. It is desirable. However, in order to generate both the A-phase signal and the B-phase signal and also specify the rotation direction, it is desirable that at least three detection units G1 to G4 are arranged.

  Moreover, although the said embodiment demonstrated the case where only one track T was set, multiple tracks T may be set. In this case, at least one or more detection units are arranged corresponding to each track T, and a total of two or more detection units are arranged. When a plurality of tracks T are provided, for example, the tracks T are set at different positions on the same surface (measurement surfaces 111, 211) and the distance r to the drive axis AX. Further, for example, it is possible to set one or more tracks T on each measurement surface by using both surfaces of the disk T as measurement surfaces. In this case, each detection unit is arranged to face the corresponding track T.

  In the above embodiment, since the measurement surfaces 111 and 211 are inclined by the angle α with respect to the plane perpendicular to the drive axis AX, the uppermost PU and the lowermost PD become one point in the track T. Yes. Therefore, each of the detection signals G1 to G4 changes in one cycle with respect to one rotation of the rotation position θ (see FIGS. 6 and 14). However, the present invention is not limited to this example. For example, the detection signals G1 to G4 that change two cycles within one rotation are obtained by arranging the curved disk 210 perpendicularly to the drive axis AX without tilting or by more complicatedly curving the surface of the disk 210. Is also possible. In this case, it is also possible to obtain detection signals G1 to G4 that change by two or more cycles within one rotation by changing the bending cycle of the disk 210. However, in the case where the detection signals G1 to G4 that change by one cycle in one rotation are used as in the above embodiments, the absolute rotation position θ within one rotation can be easily specified. Note that when the track T is configured to change by two or more n periods within one rotation, at least two detection units (m = 1, 2,...), For example, around the drive axis AX, It is desirable to arrange at the position of the angle φ, and it is desirable to arrange one or more other detection units at the midpoint of the above two detectors.

DESCRIPTION OF SYMBOLS 1 Motor system 20 Motor part 21,22 Shaft 30 Motor 40 Control part 100 Encoder 110,210 Disk 111,211 Measurement surface 112 V-groove 120 Position specific part A Reference surface AX Drive shaft T track S1, S2, S3, S4 detection Part G1, G2, G3, G4 Detection signal θ Rotation position z Linear position α Angle O Center position r Distance Δz Distance difference z1, z2 Linear position L1, L2, L3, L4 Distance

Claims (8)

A linear motion that can be rotated around one drive axis and can be coupled to a detection target that can move linearly along the drive axis, and that can rotate and move linearly following the rotation and linear movement of the detection target. A rotating part;
A shape that is provided on the surface in the drive shaft direction of the linear motion rotating portion, has a constant distance to the drive shaft, and changes its position in the drive shaft direction for one cycle or more within one rotation of the linear motion rotating portion. One or more ring-shaped tracks having
Two or more detection units that are respectively fixedly arranged facing the one or more tracks and that detect detection signals according to the distance along the drive axis to the one track facing each other;
A position specifying unit that specifies a linear position of the detection target in the drive axis direction and a rotational position around the drive axis based on the two or more detection signals detected by the two or more detection units;
A linear motion rotary encoder. The surface in the drive axis direction of the linear motion rotating unit is a planar measurement surface inclined at a predetermined angle from a plane perpendicular to the drive axis,
The linear motion rotary encoder according to claim 1, wherein the one track is formed on the measurement surface. Each of the two or more detection units detects the detection signal by irradiating irradiation light to the one opposed track and receiving reflected light from the track,
The linear motion rotary encoder according to claim 1, wherein the one opposed track has a reflection shape that increases the amount of light reflected toward the one opposed detection unit.   4. The linear motion rotary encoder according to claim 3, wherein the one opposed track has a substantially V-shaped groove formed over the entire circumference of the ring as the reflective shape. 5.   2. The linear motion rotary encoder according to claim 1, wherein at least one of the tracks is formed in a shape in which a position in the drive axis direction changes linearly with respect to an angle around the measurement axis except an inflection point.   The measurement surface of the at least one track is a cut in which one end is connected to the detection target and the other end of the shaft extended along the drive shaft is cut at a predetermined angle with respect to the drive shaft. The linear motion rotary encoder according to claim 2, which is a surface. A linear motion motor unit that is rotatable about a drive shaft in which the shaft can be connected to one end and that can be linearly moved along the drive shaft;
A linear motion rotating part fixed to the other end of the shaft and capable of rotating and linearly moving following the rotation and linear movement of the detection target;
A shape that is provided on the surface in the drive shaft direction of the linear motion rotating portion, has a constant distance to the drive shaft, and changes its position in the drive shaft direction for one cycle or more within one rotation of the linear motion rotating portion. One or more ring-shaped tracks having
Two or more detection units that are respectively fixedly arranged facing the one or more tracks and that detect detection signals according to the distance along the drive axis to the one track facing each other;
A position specifying unit that specifies a linear position of the detection target in the drive axis direction and a rotational position around the drive axis based on the two or more detection signals detected by the two or more detection units;
A linear motion rotary motor. A linear motion motor unit that is rotatable about a drive shaft in which the shaft can be connected to one end and that can be linearly moved along the drive shaft;
A linear motion rotating part fixed to the other end of the shaft and capable of rotating and linearly moving following the rotation and linear movement of the detection target;
A shape that is provided on the surface in the drive shaft direction of the linear motion rotating portion, has a constant distance to the drive shaft, and changes its position in the drive shaft direction for one cycle or more within one rotation of the linear motion rotating portion. One or more ring-shaped tracks having
Two or more detection units that are respectively fixedly arranged facing the one or more tracks and that detect detection signals according to the distance along the drive axis to the one track facing each other;
A position specifying unit that specifies a linear position of the detection target in the drive axis direction and a rotational position around the drive axis based on the two or more detection signals detected by the two or more detection units;
A control unit for controlling the linear motion rotation motor unit based on the linear position and the rotation position of the detection target specified by the position specifying unit;
A linear motion rotary motor system.