JP6535645B2 - Absolute encoder - Google Patents

Description

  The present invention relates to an absolute encoder for detecting the amount of rotation of a spindle.

  2. Description of the Related Art Conventionally, rotary encoders used to detect the position and angle of a movable element in various control mechanical devices are known. Such encoders include an incremental encoder that detects relative position or angle, and an absolute encoder that detects absolute position or angle. For example, Patent Document 1 discloses an absolute type for digitally measuring, as an absolute amount, a rotation amount of a rotary shaft for motion control such as an automatic control device or a robot device or a rotary shaft for power transmission used to open or close a valve. A rotary encoder is described.

Japanese Utility Model Application Publication No. 4-96019

  The absolute encoder described in Patent Document 1 has a configuration in which a 1-bit rotation sensor is attached to the rotation shaft of each of the multistage-connected gears. Each of these gears is sequentially decelerated and rotated by 1⁄2 to configure a 1-bit counter. In such an encoder, since the resolution decreases as the number of counters decreases, increasing the number of counters in order to secure the resolution causes a problem that the size of the encoder increases.

  The present invention has been made in view of such problems, and it is an object of the present invention to provide an absolute encoder that is advantageous for downsizing while securing resolution.

In order to solve the above problems, an absolute encoder according to an aspect of the present invention is an absolute encoder that detects a rotation amount that is a sum of rotation angles over multiple rotations of a main shaft, and the first one rotates integrally with the main shaft A gear portion and a gear portion meshing with the continuously rotating first gear portion and intermittently rotating, the second gear portion rotating at a speed reduction ratio predetermined with respect to the first gear portion, and continuously rotating A gear portion engaged with the two gear portions and intermittently rotated, and a third gear portion rotating at a reduced speed with respect to the second gear portion at a predetermined reduction ratio, and a first rotation angle of the first gear portion A magnetic angle sensor, a second magnetic angle sensor for detecting a rotation angle of the second gear portion, and a third angle sensor for detecting a rotation angle of the third gear portion . The third angle sensor is a rotary code switch including a switch element for outputting a digital signal according to the rotation angle of the third gear portion, or a magnetic angle sensor having a resolution higher than the resolution of the second angle sensor. rotation angle and rotation speed, the rotation angle of the first gear unit, the rotation angle of the second gear unit, and the rotation angle of the third gear unit, in Ru identified.

  According to this aspect, in the absolute encoder, it is possible to specify the amount of rotation which is the sum of the rotation angles over the plurality of rotations of the main spindle based on the output signals from the first angle sensor and the second angle sensor.

Another aspect of the present invention is also an absolute encoder. The absolute encoder is a absolute encoder for detecting the rotation amount based on the rotation angle and rotation speed over a plurality of revolutions of the main shaft, a first gear unit that rotates the spindle and integral with the first gear portion continuous rotation A second gear portion engaged with the first gear portion and engaged with the second gear portion so as to sequentially decrease the amount of rotation of the second gear portion. A first magnetic angle sensor that detects the rotation angle of the first gear section and gears of the first to Nth (N is an integer of 1 or more) stages that intermittently rotate at the same rotation speed as the former stage when the former stage continuously rotates And a second magnetic angle sensor that detects the rotation angle of the second gear portion, and a rotation sensor that detects the rotation of each of the first to N-th gears. The rotation sensor is a rotary code switch including a switch element that outputs a digital signal according to the rotation angle of each of the first to N-th gears, or a magnetic angle sensor having a resolution higher than that of the second angle sensor. The rotation angle and the number of rotations of the main shaft are specified by the rotation angle of the first gear portion, the rotation angle of the second gear portion, and the rotation angles of the first to N-th gears.

Yet another aspect of the present invention is also an absolute encoder. This absolute encoder is an absolute encoder that detects the amount of rotation based on the rotation angle and the number of rotations over a plurality of rotations of the main shaft, and the first gear portion integrally rotating with the main shaft and the rotation amount of the first gear portion Gears of the first to N-th (N is an integer of 1 or more) gears that are connected to decrease sequentially and intermittently rotate at the same rotation speed as the former when the former rotates continuously, and the N-th gear that rotates continuously meshing a gear portion which rotates intermittently, and a second gear portion connected at a predetermined reduction ratio relative to the gear of the first N-stage, first magnetic angle for detecting the rotation angle of the first gear unit A sensor, a rotation sensor that detects the rotation of each of the first to N-th gear wheels, and a second angle sensor that detects the rotation angle of the second gear portion. The rotation sensor is a magnetic angle sensor that detects the rotation angles of the first to N-th gears, and the second angle sensor is a switch element that outputs a digital signal according to the rotation angle of the second gear portion. And a magnetic code sensor having resolution higher than the resolution of the rotation sensor, wherein the rotation angle and the number of rotations of the main shaft are the rotation angle of the first gear portion and the gears of the first to N-th gears. And the rotation angle of the second gear portion.

  It is to be noted that any combination of the above-described components or any component or expression of the present invention, which is mutually substituted among methods, apparatuses, systems, etc., is also an aspect of the present invention.

  According to the present invention, it is possible to provide an absolute encoder that is advantageous for downsizing while securing resolution.

FIG. 1 is a schematic view of an apparatus including a ball screw mechanism driven by a motor provided with an encoder. It is a schematic diagram which shows the encoder which concerns on 1st Embodiment. It is a front view showing an encoder concerning a 1st embodiment. FIG. 5 is a layout view of top view of each gear portion of the encoder of FIG. 3; FIG. 5 is a layout view of each gear portion of the encoder of FIG. 3 as viewed from below. FIG. 4 is a layout view of each angle sensor, each hole detector, and control unit of the encoder of FIG. 3 as viewed from below. It is a schematic diagram which shows the encoder which concerns on 2nd Embodiment. It is a front view showing an encoder concerning a 2nd embodiment. FIG. 9 is a layout view of each gear portion of the encoder of FIG. 8 as viewed from above. FIG. 9 is a layout view of each gear portion of the encoder of FIG. 8 as viewed from below. FIG. 9 is a layout view of each angle sensor, each hole detector, and control unit of the encoder of FIG. 8 as viewed from below. It is a schematic diagram which shows the encoder which concerns on 3rd Embodiment. It is a front view showing an encoder concerning a 3rd embodiment. FIG. 14 is a top plan view layout diagram of each gear portion of the encoder of FIG. 13; FIG. 14 is a layout view of each gear portion of the encoder of FIG. 13 as viewed from below. FIG. 14 is a layout view of the angle sensors, the hole detectors, and the control unit of the encoder of FIG. 13 as viewed from below.

  FIG. 1 is a schematic view of an apparatus 104 including a ball screw mechanism 105 driven by a motor 107 having an encoder 100. Here, the ball screw mechanism 105 is configured by combining a screw shaft 105s with a nut (not shown) and a ball (not shown), and is an element that converts rotational motion into linear motion. The device 104 converts the rotational motion of the main shaft 8 of the motor 107 into linear motion in the Z-axis direction by the ball screw mechanism 105 to move the movable portion 105m to a desired position on the screw shaft 105s. The screw shaft 105 s of the ball screw mechanism 105 rotates integrally with the main shaft 8 of the motor 107. The encoder 100 detects the amount of rotation over a plurality of rotations of the main shaft 8 in order to detect the position of the movable portion 105 m in the Z-axis direction by replacing it with the rotation position of the main shaft 8. The sum total of rotation angles (hereinafter, referred to as the rotation amount of the main shaft) over a plurality of rotations from the initial position of the main shaft 8 is proportional to the displacement distance from the initial position of the movable portion 105m. Therefore, the position of the movable portion 105m can be detected by detecting the amount of rotation of the main shaft 8 by specifying the proportional constant of the amount of rotation of the main shaft 8 and the displacement distance of the movable portion 105m.

  As such an encoder, for example, it can be considered to be configured by combining a plurality of angle sensors that detect an absolute rotation angle within one rotation of the main shaft and output as a digital signal. As an example of an encoder combining a plurality of angle sensors, a configuration is considered in which separate angle sensors are provided for each of three axes of the first and second auxiliary axes that rotate at a reduction ratio different from that of the main axis. In this configuration, the amount of rotation over a plurality of rotations of the main spindle is calculated digitally based on the rotation angles detected from the three axes of the main spindle, the first slave axis and the second slave axis. The term “digital operation” includes, for example, operation using an amount converted into N base. In this configuration, since the amount of rotation is calculated from the rotation angle, if the resolution of any of the rotation angles detected by a plurality of angle sensors (hereinafter, detected rotation angles) is low, the accuracy of the amount of rotation calculated and obtained There is a problem of falling. In order to improve this accuracy, it is also conceivable to mount high-resolution angle sensors on all three axes, but in this case, there is a problem that cost reduction is disadvantageous by providing three expensive angle sensors.

  Further, in this configuration, the detection rotation angle (digital signal) of each of these three angle sensors is calculated by a CPU (central processing unit) using a complicated algorithm to obtain the rotation amount. Therefore, there is a problem that if the CPU having a low computing ability is used, the operation can not catch up and malfunctions. From these problems, there is room for improvement in the configuration in which a plurality of rotation angles are processed in parallel to detect the amount of rotation from the viewpoint of improving the accuracy while suppressing the cost increase.

Based on these, the amount of rotation over multiple rotations of the main spindle (hereinafter referred to as multiple rotations) is determined by Equation 1 based on the rotation angle within one rotation of the main spindle and the number of rotations of the main spindle. .
(Expression 1) Spindle rotation amount = Spindle rotation angle + Spindle rotation number × 360 °
The present invention has been made based on such recognition, and provides an absolute encoder for obtaining the amount of rotation based on the rotation angle and the number of rotations of a main shaft.

Hereinafter, the present invention will be described based on several preferred embodiments with reference to the drawings. In the embodiment and the modification, the same or equivalent constituent elements and members are denoted by the same reference numerals, and duplicating descriptions are appropriately omitted. In addition, dimensions of members in each drawing are shown appropriately enlarged or reduced for easy understanding. Moreover, in each drawing, a part of members which are not important in describing the first embodiment will be omitted and displayed.
Also, although terms including first and second ordinal numbers are used to describe various components, this term is used only to distinguish one component from another component, and this term The constituent elements are not limited by

First Embodiment
An encoder 100 according to a first embodiment of the present invention will be described. FIG. 2 is a schematic view showing the encoder 100. As shown in FIG. FIG. 3 is a front view showing the encoder 100. As shown in FIG. The following description is based on the XYZ orthogonal coordinate system. The X-axis direction corresponds to horizontal horizontal direction, the Y-axis direction corresponds to horizontal horizontal direction, and the Z-axis direction corresponds to vertical vertical direction. The Y-axis direction and the Z-axis direction are orthogonal to the X-axis direction. The X-axis direction may be described as the left direction or the right direction, the Y-axis direction as the front direction or the back direction, the positive direction as the Z-axis direction as upward, and the negative direction as the Z-axis direction as downward. In particular, the second substrate 128 side is referred to as the upper side when viewed from the first substrate 126 side described later, and the first substrate 126 side is referred to as the lower side when viewed from the second substrate 128 side. The notation of such a direction does not limit the use posture of the encoder 100, and the encoder 100 can be used in any posture.

  The encoder 100 is an absolute type encoder that detects the amount of rotation of the main spindle 8 over multiple rotations. The encoder 100 outputs the detected amount of rotation of the main shaft 8 as a digital signal. As shown in FIG. 2, the encoder 100 includes a first rotor 108, a second rotor 109, a third rotor 110, a first angle sensor 116, a second angle sensor 118, and a third angle sensor 120; A transmission unit G1, a transmission unit G2, a transmission unit G3, and a control unit 122 are mainly included. These rotors rotate at different speeds in conjunction with the rotation of the main shaft 8. The first rotor 108 rotates integrally with the main shaft 8. The second rotor 109 decelerates and rotates from the first rotor 108 via the transmission portion G1 of the transmission ratio P1 and the transmission portion G2 of the transmission ratio P2. The third rotor 110 is decelerated and rotated from the second rotor 109 via the transmission portion G3 of the gear ratio P3. Here, the gear ratio refers to the rotational ratio as compared to the first rotor 108, and for example, the gear ratio P1 refers to the rotational ratio of the transmission portion G1 to the first rotor 108. The same applies to the other P2 and P3.

  The first angle sensor 116 detects the rotation angle of the first rotor 108 (= rotation angle of the main shaft 8). The first rotor 108, the magnet M1, the first angle sensor 116, and the first acquisition unit 41 constitute a first specific element 71 that specifies the rotation angle of the main shaft 8. The second angle sensor 118 detects the rotation angle of the second rotor 109. The second rotor 109, the magnet M2, the second angle sensor 118, and the second acquisition unit 42 constitute a second specific element 72 that specifies the rotation angle of the second rotor 109. The third angle sensor 120 detects the rotation angle of the third rotor 110. The third rotor 110, the third angle sensor 120, and the third acquisition unit 43 constitute a third specific element 73 that specifies the rotation angle of the third rotor 110.

The control unit 122 specifies the number of rotations of the main shaft 8 based on the rotation angles detected by the second angle sensor 118 and the third angle sensor 120, and also detects the number of rotations and the first rotor 108 detected by the first angle sensor 116. The rotation angle of the main shaft 8 is specified based on the rotation angle of. That is, the control unit 122 specifies the amount of rotation of the main shaft 8 based on the rotation angles detected by the first angle sensor 116, the second angle sensor 118, and the third angle sensor 120. For example, the amount of rotation of the main shaft 8 can be specified by Equation 2.
(Expression 2) Amount of rotation of main shaft 8 = rotation angle of first rotor 108 + P1 × P2 × (rotation angle of second rotor 109 + P3 × rotation angle of third rotor 110)
The control unit 122 will be described later.

  Subsequently, the detailed configuration of the encoder 100 will be described. As shown in FIG. 3, the encoder 100 includes a first substrate 126, a second substrate 128, an intermediate gear portion 115 disposed between the first substrate 126 and the second substrate 128 in the Z-axis direction, and a magnet It further includes M1 and a magnet M2. In addition, a first gear portion 112 is provided to the first rotor 108, a second gear portion 113 is provided to the second rotor 109, and a third gear portion 114 is provided to the third rotor 110. The rotation axis of the first rotor 108 and the rotation axis of the first gear portion 112, the rotation axis of the second rotor 109 and the rotation axis of the second gear portion 113, the rotation axis of the third rotor 110 and the rotation axis of the third gear portion 114 Are arranged to be the same. FIG. 4 is a layout view of each gear portion of the encoder 100 as viewed from the second substrate 128 side. FIG. 5 is a layout view of each gear portion of the encoder 100 as viewed from the first substrate 126 side. FIG. 6 is a layout view of each angle sensor, each hole detector, and the control unit 122 of the encoder 100 viewed from the first substrate 126 side. In addition, in FIGS. 4 to 6, the description of a part of the gear portion is omitted to facilitate understanding.

(First board)
The first substrate 126 is a substantially flat member provided on the motor 107 side (lower side in FIG. 3) of the encoder 100. The first substrate 126 may be formed by molding using, for example, a resin material. The first substrate 126 has a hole 126 h through which the main shaft 8 is inserted. The first substrate 126 is provided with four shafts (not shown) for rotatably supporting the intermediate gear portion 115, the second rotor 109, and the third rotor 110, and these four shafts are the first substrate. It is orthogonal to 126 and extends towards the second substrate 128. These four shafts constitute a rotating shaft. A central portion of each rotor 108, 109, 110 is provided with a bearing (not shown) rotatably supporting the shaft. A rolling bearing or a sliding bearing may be used as this bearing.

(Second board)
As shown in FIG. 3, the second substrate 128 is a substantially flat member provided on the side opposite to the first substrate 126 of the encoder 100. The second substrate 128 may be fixed to a plurality of bosses (not shown) provided on the first substrate 126. As shown in FIG. 6, the second substrate 128 supports the first angle sensor 116, the second angle sensor 118, the third angle sensor 120, and the control unit 122. The second substrate 128 may be, for example, a printed wiring board provided with wiring of each sensor and control unit. The central portion of the first angle sensor 116 is disposed on the extension of the rotation axis R1 of the first rotor 108 and faces the magnet M1. The central portion of the second angle sensor 118 is disposed on the extension of the rotation axis R2 of the second rotor 109 and faces the magnet M2. The central portion of the third angle sensor 120 is disposed on the extension of the rotation axis R3 of the third rotor 110.

(Angle sensor)
The first angle sensor 116, the second angle sensor 118, and the third angle sensor 120 (hereinafter sometimes referred to as each angle sensor) have an absolute rotation in the range of 0 ° to 360 ° corresponding to one rotation. It is a sensor that detects an angle. Each angle sensor outputs a signal (for example, a digital signal) corresponding to the detected rotation angle to the control unit 122. The first angle sensor 116, the second angle sensor 118, and the third angle sensor 120 output to the control unit 122 the same rotation angle as before stopping the energization, even when the energization is once stopped and re-energized. Therefore, a configuration without backup power is possible. As shown in FIG. 6, each angle sensor 116, 118, 120 is fixed at a predetermined position or a predetermined position of the second substrate 128 by means such as soldering. In FIG. 6, circular broken lines surrounding the first angle sensor 116 and the second angle sensor 118 indicate the outer shapes of the magnets M1 and M2 projected onto the second substrate 128.

  The first angle sensor 116 and the second angle sensor 118 may use magnetic angle sensors with relatively high resolution. The magnetic angle sensor is disposed opposite to the magnetic pole of the magnet via a gap in the Z-axis direction, for example, and the rotation angle of the rotor is specified based on the rotation of these magnetic poles and a digital signal is output to the control unit 122 Do. The magnetic angle sensor includes, as an example, a detection element that detects a magnetic pole, and an arithmetic circuit that outputs a digital signal based on the output of the detection element. The detection element may include a plurality (for example, four) of magnetic field detection elements such as a Hall element or a GMR (Giant Magneto Resistive) element. The arithmetic circuit may specify the rotation angle by table processing using a look-up table using, for example, differences and ratios of outputs of the plurality of detection elements as a key. The detection element and the arithmetic circuit may be integrated on one IC chip. The IC chip may be embedded in a resin having a thin rectangular solid outer shape. The first angle sensor 116 outputs an angle signal which is a parallel digital signal corresponding to the detected rotation angle of the main shaft 8 to a plurality of output terminals exposed from the resin.

  As the third angle sensor 120, a magnetic angle sensor similar to the first angle sensor 116 may be used, but in the first embodiment, a rotary cord switch is used. The rotary code switch may include a switch element for outputting a multi-bit (for example, 4 bits) digital signal according to the rotation angle of the rotor. The rotary cord switch is simpler in construction and less expensive than a magnetic angle sensor. As shown in FIG. 3, the input shaft 120 s of the third angle sensor 120 is a recess 110 h formed at the center of the cylindrical portion 110 s extending from the center of the third rotor 110 toward the second substrate 128. It is inserted and fixed.

  The resolution of the third angle sensor 120 may be higher than the resolution of the second angle sensor 118. For example, a magnetic angle sensor having a resolution of 7 bits may be used as the third angle sensor 120, and a rotary code switch having a resolution of 4 bits may be used as the second angle sensor 118. Compared with a configuration in which an angle sensor with a resolution of 1/16 rotation (4 bits) is disposed after the second gear rotating slowly by 1/128 rotation, the second gear rotates 1/16 rotation relatively fast. If an angle sensor with a resolution of 1/128 (7 bits) is disposed at a later stage, the effect of gear backlash is smaller, and it is easier to suppress the occurrence of counting errors.

(magnet)
The magnet M1 and the magnet M2 (hereinafter sometimes referred to as each magnet) have a substantially cylindrical shape and are, for example, bonded magnets formed of NdFeB-based magnet materials. Two magnetic poles are provided in the radial direction at the end of each magnet on the second substrate 128 side. In other words, two magnetic poles are provided side by side in the circumferential direction. The respective magnets are accommodated in respective concave portions 108h and 109h formed in the respective support portions 108s and 109s extending (upwardly) from the respective rotors 108 and 109 toward the second substrate 128, and fixed using, for example, an adhesive. Ru. The first angle sensor 116 detects the magnetic pole of the magnet M1 provided on the first rotor 108, and outputs the rotation angle of the first rotor 108 as a digital signal of a plurality of bits (for example, 7 bits). The second angle sensor 118 detects the magnetic pole of the magnet M2 provided on the second rotor 109, and outputs the rotation angle of the second rotor 109 as a digital signal of a plurality of bits (for example, 7 bits).

(Reduction mechanism)
As shown in FIGS. 3 to 5, the first gear portion 112 is provided with a toothless gear, and the intermediate gear portion 115 is provided with a Geneva mechanism. The first gear portion 112 and the intermediate gear portion 115 are coupled by a toothless gear and a Geneva mechanism to form a transmission portion G1 having a gear ratio of P1. The intermediate gear portion 115 and the second gear portion 113 are geared to form a transmission portion G2 having a gear ratio of P2. Similarly, the second gear portion 113 and the third gear portion 114 are coupled by a toothless gear and a Geneva mechanism to form a transmission portion G3 having a gear ratio of P3. The transmission unit G1, the transmission unit G2, and the transmission unit G3 constitute a speed reduction mechanism that gradually decelerates. The first rotor 108, the intermediate gear portion 115, the second rotor 109, and the third rotor 110 rotate in conjunction with this speed reduction mechanism. That is, as the first rotor 108 rotates, the second rotor 109 and the third rotor 110 decelerate and rotate at a preset reduction ratio. The first gear portion 112 and the intermediate gear portion 115 are coupled by a toothless gear and a Geneva mechanism to constitute a transmission portion G1 having a transmission ratio P1. Similarly, the second gear portion 113 and the third gear portion 114 are coupled by a toothless gear and a Geneva mechanism to constitute a transmission portion G3 having a transmission ratio P3.
However, since the transmission is by the Geneva mechanism, transmission is not by continuous rotation but by intermittent rotation, and the rotation of the main shaft 8 is not discrete rotation angle but discrete rotation position representing the number of rotations of the main shaft 8. , 110.

(First gear section)
The first gear portion 112 includes a drive gear 112 d provided in order from the second substrate 128 side (top), and a cam portion 112 c. The drive gear is a gear to be driven. The gear driven by the drive gear is called a driven gear. The cam portion 112c and the drive gear 112d each have a substantially cylindrical outer shape in which predetermined unevenness or gear teeth are provided on the outer peripheral surface. The cam portion 112c and the drive gear 112d may be integrally formed, and may further include the same rotation axis. The rotation of the first rotor 108 is transmitted to the intermediate gear portion 115 by the drive gear 112 d meshing with the driven gear 115 e of the intermediate gear portion 115. The cam portion 112 c meshes with the cam portion 115 c of the intermediate gear portion 115 to restrict the irregular rotation of the intermediate gear portion 115. Here, non-regular rotation refers to rotation other than rotation which is normally transmitted when the driven gear meshes with the drive gear. The same applies to the part where the following driven gear meshes with the drive gear. The drive gear 112d of the first gear portion 112 is a toothless portion having a portion having two teeth at two consecutive positions among the positions obtained by equally dividing the outer periphery thereof into two, and a portion not provided with a tooth at another portion And a partially toothed gear. That is, the drive gear 112 d is a toothless gear having gear teeth whose angle is 60 °. The cam portion 112c of the first gear portion and the cam portion 115c of the intermediate gear portion constitute a Geneva mechanism driven by the drive gear 112d of the first gear portion and the driven gear 115e of the intermediate gear portion.

(Intermediate gear)
The intermediate gear portion 115 is an element that decelerates and transmits the rotation between the first rotor 108 and the second rotor 109. By providing the intermediate gear portion 115, the reduction ratio between the first rotor 108 and the second rotor 109 can be increased. The intermediate gear portion 115 includes a driven gear 115 e provided in order from the second substrate 128 side (upper side), a cam portion 115 c, and a drive gear 115 d. The cam portion 115c, the driven gear 115e, and the drive gear 115d each have a substantially cylindrical outer shape in which predetermined unevenness or gear teeth are provided on the outer peripheral surface. The cam portion 115c, the driven gear 115e and the drive gear 115d may be integrally formed, and may further include the same rotation shaft. The rotation of the first rotor 108 is transmitted to the intermediate gear portion 115 by the driven gear 115 e meshing with the drive gear 112 d of the first gear portion 112.

  The driven gear 115e is a spur gear having 48 gear teeth at positions obtained by equally dividing the outer circumference thereof into 48. The drive gear 112d of the first gear portion 112 is a toothless portion having a portion having two teeth at two consecutive positions among the positions obtained by equally dividing the outer periphery thereof into two, and a portion not provided with a tooth at another portion And a partially toothed gear. The cam portion 115c of the intermediate gear portion is a Geneva wheel consisting of cams that divide the outer circumference into eighteen equal parts. The cam portion 112c of the first gear portion has a locking element for restricting the irregular rotation of the Geneva wheel at one location on the outer periphery, and the cam portion 112c of the first gear portion and the cam portion 115c of the intermediate gear portion A Geneva mechanism having a division ratio 18 which is driven by the drive gear 112d of one gear portion and the driven gear 115e of the intermediate gear portion is configured. The intermediate gear portion 115 is intermittently driven by the Geneva mechanism. That is, when the first gear portion 112 continuously rotates, the intermediate gear portion 115 and the intermediate gear portion 115 intermittently rotate at a division ratio P1 of 18. The pitch circle diameter of the driven gear is slightly larger than the pitch circle diameter of the cam portion. That is, the tip end of the tooth of the driven gear 115e protrudes to the outer peripheral side (the first gear portion 112 side) than the cam portion 115c.

  The drive gear 115 d of the intermediate gear portion 115 is a spur gear having 12 gear teeth at positions where the outer periphery thereof is divided into 12 equal parts.

(2nd gear part)
The second gear portion 113 includes a driven gear 113e provided in order from the second substrate 128 side (upper side), a cam portion 113c, and a drive gear 113d. The driven gear 113e, the drive gear 113d, and the cam portion 113c each have a substantially cylindrical outer shape in which predetermined unevenness or gear teeth are provided on the outer peripheral surface. The driven gear 113e, the drive gear 113d and the cam portion 113c may be integrally formed, and may further include the same rotation shaft. The rotation of the intermediate gear portion 115 is transmitted to the second rotor 109 by meshing the driven gear 113 e with the drive gear 115 d of the intermediate gear portion 115.

  The driven gear 113e is a spur gear having 60 gear teeth at positions equally divided by 60 on the outer periphery thereof. Therefore, the second gear portion 113 is geared to the intermediate gear portion 115 at a reduction ratio P2 of 12/60 (= 1/5). That is, the drive gear 115d and the driven gear 113e constitute a transmission portion G2 having a gear ratio P2 of five. With this configuration, while the second rotor 109 makes one rotation, the main shaft 8 rotates 90 times which is the product of P1 (= 18) and P2 (= 5), and detects the rotation angle of the second rotor 109. The rotational speed of the main spindle 8 over 90 rotations can be detected.

  The drive gear 113d of the second gear portion 113 has a missing tooth portion which is a portion having two teeth at two successive positions among the positions obtained by equally dividing the outer periphery thereof into two portions and a portion not provided with a tooth at another portion And a partially toothed gear. That is, the drive gear 113 d is a toothless gear having gear teeth by 36 °. The drive gear 113 d of the second gear portion 113 meshes with the driven gear 114 e of the third gear portion 114. The cam portion 113 c of the second gear portion 113 meshes with the cam portion 114 c of the third gear portion 114.

(Third gear section)
The third gear portion 114 includes a cam portion 114c provided in order from the second substrate 128 side (top), and a driven gear 114e. The cam portion 114c and the driven gear 114e each have a substantially cylindrical outer shape in which predetermined unevenness or gear teeth are provided on the outer peripheral surface. The cam portion 114c and the driven gear 114e may be integrally formed, and may further include the same rotation shaft. The driven gear 114e of the third gear portion 114 is a spur gear having 44 gear teeth at 44 equally divided positions on the outer periphery thereof. The cam portion 114c of the third gear portion is a Geneva wheel consisting of cams that divide the outer circumference into 16 equal parts, and the cam portion 113c of the second gear portion is a lock that restricts irregular rotation of the one Geneva wheel at its outer circumference Having a component, the cam portion 113c of the second gear portion and the cam portion 114c of the third gear portion are driven by the drive gear 113d of the second gear portion and the driven gear 114e of the third gear portion. It constitutes a mechanism. That is, the second gear portion and the third gear portion constitute a transmission portion G3 having a gear ratio P3 of 16. With this configuration, when the third rotor 110 makes one rotation, the second rotor 109 rotates 16 times corresponding to the gear ratio P3, and the main shaft 8 corresponds to the product of the gear ratio P1 and the gear ratio P2. It has been rotated 1440 times. Therefore, by detecting the rotation angle of the third rotor 110, it is possible to detect the number of rotations over 1440 rotations of the main shaft.

(Control unit)
Please refer to FIG. The control unit 122 includes a first acquisition unit 41, a second acquisition unit 42, a third acquisition unit 43, a rotation number identification unit 45, a rotation amount identification unit 44, and an output unit 46. Each of these blocks can be realized by hardware as an element such as a CPU (central processing unit) of a computer or by a mechanical device, and as software as a computer program or the like. It depicts the functional blocks realized by cooperation. Therefore, it is understood by those skilled in the art who have been mentioned herein that these functional blocks can be realized in various forms by a combination of hardware and software.

  The first acquisition unit 41 acquires a signal output from the first angle sensor 116 (hereinafter referred to as an output signal), arranges it into data of a predetermined format, and sends it to the rotation amount identification unit 44. The second acquisition unit 42 acquires an output signal from the second angle sensor 118, arranges it into data of a predetermined format, and sends the data to the rotation speed identification unit 45. The third acquisition unit 43 acquires an output signal from the third angle sensor 120, arranges it into data of a predetermined format, and sends the data to the rotation speed identification unit 45. The rotation number specifying unit 45 specifies the number of rotations of the first rotor 108 (= the number of rotations of the main shaft 8) based on the output data from the first acquisition unit 41 and the output data from the second acquisition unit 42, and specifies the rotation amount. Send to section 44. The rotation amount specifying unit 44 specifies the rotation amount of the main shaft 8 by the above-mentioned equation 2 based on the output data from the first acquisition unit 41 and the output data from the rotation number specifying unit 45. The output unit 46 outputs the amount of rotation of the spindle 8 specified by the amount-of-rotation specifying unit 44 in a predetermined format. The signal output from the output unit 46 may be a parallel digital signal.

  Here, when each bit of the digital signal from the output unit 46 is divided from the upper side to the lower side, the upper side bit is the upper side bit, the lower side bit is the middle order bit, and the lower side bit When the lower bit is referred to, as shown in Equation 2, the output signal from the third angle sensor 120 is mainly the upper bit, the output signal from the second angle sensor 118 is mainly the middle bit, and from the first angle sensor 116 The output signal of corresponds mainly to the area of lower bits. Therefore, even when the resolutions of the three angle sensors are different, the influence on the detection accuracy can be reduced. Further, since the operation according to Equation 2 is simple, the amount of operation can be small, and a CPU having a low operation capability can be used for the control unit 122.

Next, a method of manufacturing the encoder 100 according to the first embodiment configured as described above will be described. The method of manufacturing the encoder 100 may include the step of sequentially stacking and assembling the upper members on a part of the lower members.
(1) Prepare the motor 107 and the first substrate 126 on which the shaft (not shown) is erected.
(2) The motor 107 is fixed to the jig with the main shaft 8 directed upward. The main shaft 8 is inserted into the hole 126 h to fix the first substrate 126 on the upper side of the motor 107.
(3) The first rotor 108 is fixed by covering the main shaft 8 from the side (upper side) where the second substrate 128 is provided.
(4) Attach the third rotor 110 to the first substrate 126. At this time, the bearing (not shown) of the third rotor 110 is fitted to the shaft of the first substrate 126 from the side (upper side) on which the second substrate 128 is provided.
(5) The second rotor 109 is attached to the first substrate 126 so as to cover a part of the third rotor 110. At this time, the bearing (not shown) of the second rotor 109 is fitted to the shaft of the first substrate 126 from the second substrate 128 side (upper side).
(6) The intermediate gear portion 115 is attached to the first substrate 126 so as to cover a part of the second rotor 109. At this time, the bearing (not shown) of the intermediate gear portion 115 is fitted to the shaft of the first substrate 126 from the second substrate 128 side (upper side).
(7) The second substrate 128 to which the first angle sensor 116, the second angle sensor 118, the third angle sensor 120, and the control unit 122 are attached is fixed to the first substrate 126 via a plurality of bosses (not shown) or the like. Do. At this time, the input shaft 120 s of the third angle sensor 120 is fixed to the third rotor 110.
As described above, by assembling the respective members so as to be sequentially stacked on the upper side, individual work can be simplified, and the labor and cost for manufacturing can be suppressed.
The above-described processes are merely examples, and the order of the processes may be changed, another process may be added, or some processes may be deleted as necessary.

Next, the encoder 100 according to the first embodiment configured as described above will be described.
The encoder 100 according to the first embodiment includes a first gear portion 112 that rotates integrally with the main shaft 8 and a gear that intermittently rotates when the first gear portion 112 continuously rotates. A second gear portion 113 that rotates at a reduced speed at a first reduction ratio, a first angle sensor 116 that detects a rotation angle of the main shaft 8, and a second angle sensor 118 that detects a rotation angle of the second gear portion 113 are provided. According to this configuration, based on the detected rotation angle of the main shaft 8 and the rotation speed of the main shaft 8 specified from the detected rotation angle of the second gear portion 113, for example, The quantity can be specified. One angle sensor detects the lower bit string of the digital signal output from the encoder 100 in the range of its resolution, and the other angle sensor detects a middle or upper bit string in the range of its resolution. Even when a plurality of different angle sensors are combined, a decrease in encoder accuracy can be suppressed. Here, when the bit string of the digital signal output from the encoder 100 is divided from the upper side to the lower side, the upper bit string is the upper bit string, the lower bit string is the middle bit string, and the lower The bit string of is called the lower bit string. The width of each bit string can be set according to the resolution of the angle sensor.

  The encoder 100 of the first embodiment is a gear that intermittently rotates when the second gear portion 113 continuously rotates, and a third gear portion 114 that rotates at a second reduction ratio relative to the second gear portion 113; And a third angle sensor 120 for detecting the rotation angle of the third gear portion 114. According to this configuration, the rotation number of the second gear portion 113 can be identified by detecting the rotation angle of the third gear portion 114. Therefore, the counting range of the rotation number of the main shaft 8 is expanded to further increase the number of rotations. The amount of rotation over a number can be identified.

  In the encoder 100 according to the first embodiment, the third angle sensor 120 has a rotary code switch including a switch element that outputs a digital signal according to the rotation angle of the third gear. According to this configuration, since the reduction in accuracy due to the difference in resolution is small, it becomes possible to adopt a relatively inexpensive rotary cord switch, which is advantageous for cost reduction.

  The encoder 100 according to the first embodiment can also be configured to set the resolution of the third angle sensor 120 higher than the resolution of the second angle sensor 118. In this configuration, the reduction ratio of the front and rear of the second gear portion 113 can be reduced to increase the rotational speed of the third gear portion 114. Therefore, the influence of the backlash of the gears can be reduced to suppress the occurrence of counting errors. become.

Second Embodiment
Subsequently, a second embodiment of the present invention will be described. In the drawings and the description of the second embodiment, the same or equivalent components and members as those of the first embodiment are denoted by the same reference numerals. The description overlapping with the first embodiment is appropriately omitted, and the configuration different from the first embodiment will be mainly described.
FIG. 7 is a schematic view showing the encoder 200. As shown in FIG. FIG. 8 is a front view showing the encoder 200. As shown in FIG. The encoder 200 differs in the configuration of the third specific element 73 for specifying the number of rotations of the main shaft 8 with respect to the encoder 100, and the other configurations are common. As shown in FIG. 7, the encoder 200 includes a third specific element 74 in place of the third specific element 73.

  The third specific element 74 is an element that specifies the number of rotations of the second rotor 109 over multiple rotations. The third specific element 74 is connected so as to sequentially halve the rotation amount of the second gear portion 113, and intermittently rotates at the same rotational speed as the former stage when the former stage is continuously rotated. And a rotation sensor for detecting the rotation of each of the first to N-th gears. The gears of the first to N-th (N is an integer of 1 or more) stages and the rotation sensors for detecting the rotation of the gears constitute detection elements. In this embodiment, this detection element is a 1-bit detection element that is a detection element that outputs 1-bit data. The 1-bit detection elements are connected in multiple stages so as to sequentially decelerate and rotate at a reduction ratio of 1/2. The third specific element 74 of the second embodiment includes a gear connected in two stages as N = 2, and a Hall detector as a rotation sensor.

  In particular, the third specific element 74 includes a fourth rotor 146, a fifth rotor 147, a magnet M4, a magnet M5, a fourth hole detector 161, a fifth hole detector 162, and a fourth acquisition unit 47. The magnets M4 and M5 have the same specifications as the magnets M1 and M2, and the outer diameter and thickness may be changed as necessary. As shown in FIG. 8, the magnets M4 and M5 are accommodated in the recesses 146h and 147h of the supports 146s and 147s extending from the fourth rotor 146 and the fifth rotor 147 to the second substrate 128 (upward), For example, it fixes using an adhesive material. The fourth hole detector 161 is disposed in the vicinity of an extension of the rotation axis R4 of the fourth rotor 146. The fifth hole detector 162 is disposed in the vicinity of an extension of the rotation axis R5 of the fifth rotor 147.

  The fourth rotor 146, the magnet M4 and the fourth hole detector 161 constitute a 1-bit detection element. The fifth rotor 147, the magnet M5 and the fifth hole detector 162 constitute another 1-bit detection element. The surface of the magnet M4 and the magnet M5 (hereinafter referred to as each magnet) facing the fourth hole detector 161 and the fifth hole detector 162 (hereinafter referred to as each hole detector) is divided into two in the radial direction. Two poles are provided. That is, the two magnetic poles are provided side by side in the circumferential direction. Each Hall detector outputs an output signal which is a digital signal of L level and H level based on the magnetic pole of each magnet. Each Hall detector may be, for example, a Hall IC. As an example, each Hall detector may output L level corresponding to the N pole and H level corresponding to the S pole. Therefore, each Hall detector outputs an output signal of one cycle every rotation of each magnet. That is, when the fourth rotor 146 makes one rotation, the fourth hole detector 161 outputs an output signal of one cycle, and when the fifth rotor 147 makes one rotation, the fifth hole detector 162 makes an output signal of one cycle. Output

  The fourth rotor 146 is intermittently rotated at a reduction ratio of 1/2 by rotation of the second rotor 109. The fifth rotor 147 is intermittently rotated at a reduction ratio of 1/2 by rotation of the fourth rotor 146. Therefore, when the fifth rotor 147 makes one revolution and outputs an output signal of one cycle, the fourth rotor 146 makes two revolutions and outputs an output signal of two cycles, and the second rotor 109 makes four revolutions, four cycles. Output the rotation angle signal of Therefore, the third specific element 74 can determine four states by the 2-bit parallel signal of two 1-bit detection elements, and can specify the number of rotations within four revolutions of the second rotor 109. The third specific element 74 increases the number of distinguishable states by increasing the number of connected 1-bit detection elements (= N) deceleratingly rotating at a reduction ratio of 1/2 sequentially to 3 or more, and thus can be specified The range of the rotational speed of the two rotors 109 can be increased.

The fourth acquisition unit 47 acquires output signals from the respective hall detectors, arranges the signals into data of a predetermined format, and sends the data to the rotation speed identification unit 45. The second acquisition unit 42 acquires the rotation angle signal from the second angle sensor 118, arranges it into data of a predetermined format, and sends it to the rotation speed identification unit 45. The rotation number identification unit 45 identifies the rotation number of the second rotor 109 based on the output data from the fourth acquisition unit 47, and identifies the rotation angle of the second rotor 109 based on the data from the second acquisition unit 42. The rotation speed specifying unit 45 specifies the rotation speed of the main shaft 8 by Equation 3 based on the specified rotation speed of the second rotor 109 and the rotation angle of the second rotor 109.
(Equation 3) Number of revolutions of main shaft 8 = P1 × P2 × (rotational angle of second rotor 109 ÷ 360 ° + number of revolutions of second rotor 109)
By substituting the rotational speed of the main shaft 8 into the above-mentioned equation 1, the amount of rotation of the main shaft 8 can be specified. The rotation amount specifying unit 44 specifies the rotation amount of the main shaft 8 based on the output data from the first acquisition unit 41 and the output data from the rotation number specifying unit 45. The output unit 46 outputs the amount of rotation of the spindle 8 specified by the amount-of-rotation specifying unit 44 in a predetermined format.

  Next, the detailed configuration of the encoder 200 according to the second embodiment will be described. FIG. 9 is a layout view of each gear portion of the encoder 200 as viewed from the second substrate 128 side. FIG. 10 is a layout view of each gear portion of the encoder 200 as viewed from the first substrate 126 side. FIG. 11 is a layout diagram of each angle sensor, each hole detector, and the control unit 124 of the encoder 200 viewed from the first substrate 126 side. In addition, in FIGS. 9-11, description of one part gear part is abbreviate | omitted in order to understand easily.

  The encoder 200 includes a first gear portion 112, an intermediate gear portion 115, a second gear portion 113, a connecting gear portion 154, a linkage gear portion 155, a fourth gear portion 156, and a fifth gear portion 157 as a reduction mechanism. The first gear portion 112, the intermediate gear portion 115, the second gear portion 113, the connecting gear portion 154, the linkage gear portion 155, the fourth gear portion 156 and the fifth gear portion 157 sequentially transmit the rotation in this order. In particular, the fourth gear portion 156 rotationally drives the fourth rotor 146, and the fifth gear portion 157 rotationally drives the fifth rotor 147.

  The first base plate 126 rotatably supports the first gear portion 112, the intermediate gear portion 115, the second gear portion 113, the connecting gear portion 154, the cooperative gear portion 155, the fourth gear portion 156, and the fifth gear portion 157. Seven shafts (not shown) are erected. At the central portion of each gear, a bearing (not shown) fitted to the shaft via a radial gap is provided. A rolling bearing or a sliding bearing may be used as this bearing.

  About the 1st gear part 112, it is the same as that of a 1st embodiment, and omits explanation. The intermediate gear portion 115 includes a drive gear 115 j instead of the drive gear 115 d. The intermediate gear portion 115 includes a cam portion 115f between the cam portion 115c and the drive gear 115j. The drive gear 115 j has a missing tooth having a portion having two teeth at two consecutive positions among the positions where the outer periphery is divided into 12 equal parts, and a missing tooth portion which is a portion where no teeth are provided at other places. It is a gear. That is, the drive gear 115 j is a toothless gear having gear teeth by 60 °. The second gear portion 113 includes a drive gear 113 j instead of the drive gear 113 d. The drive gear 113 j is a spur gear having 28 gear teeth at positions equally divided into 28 on the outer periphery thereof. The connecting gear portion 154 includes a gear 154 b which is a spur gear having 14 gear teeth at positions equally divided into 14 on the outer periphery thereof.

  The cooperative gear portion 155 includes a drive gear 155d, a cam portion 155c, and a driven gear 155e, which are provided in order from the second substrate 128 side (upper side). The drive gear 155d, the cam portion 155c and the driven gear 155e each have a substantially cylindrical outer shape provided with predetermined unevenness or gear teeth on the outer peripheral surface. The drive gear 155d, the cam portion 155c, and the driven gear 155e may be integrally formed, and may further include the same rotation shaft. The driven gear 155e is a spur gear having 28 gear teeth at positions equally divided into 28 on the outer periphery thereof. The drive gear 155d is a missing tooth having a portion having nine teeth at nine consecutive positions among the positions where the outer periphery is divided into 18 equal parts, and a missing tooth portion which is a portion where no teeth are provided at other places. It is a gear. That is, the drive gear 155d is a toothless gear having gear teeth by 180 °.

  The fourth gear portion 156 includes a drive gear 156d, a cam portion 156c, a driven gear 156e, and a cam portion 156f, which are provided in order from the second substrate 128 side (upper side). The drive gear 156d, the cam portion 156c, the driven gear 156e and the cam portion 156f each have a substantially cylindrical outer shape in which predetermined unevenness or gear teeth are provided on the outer peripheral surface. The drive gear 156d, the cam portion 156c, the driven gear 156e, and the cam portion 156f may be integrally formed, and may further have the same central axis. The driven gear 156e is a spur gear having 18 gear teeth at positions where the outer periphery thereof is divided into 18 equal parts. The drive gear 156d is a missing tooth having a portion having nine teeth at nine consecutive positions among the positions obtained by equally dividing the outer circumference into eighteen, and a missing portion which is a portion not provided with a tooth at another location. It is a gear. That is, the drive gear 156d is a toothless gear having gear teeth by 180 °.

  The fifth gear portion 157 includes a driven gear 157 e provided in order from the second substrate 128 side (top), and a cam portion 157 c. The driven gear 157e and the cam portion 157c each have a substantially cylindrical outer shape in which predetermined unevenness or gear teeth are provided on the outer peripheral surface. The driven gear 157e and the cam portion 157c may be integrally formed, and may further include the same rotation shaft. The driven gear 157e is a spur gear having 18 gear teeth at positions where the outer periphery thereof is divided into 18 equal parts.

  The cam portion 115f of the intermediate gear portion 115 meshes with the cam portion 113c, which is a Geneva wheel of the second gear portion 113, to form a transmission portion G2 having a gear ratio P2 of 20. That is, when the intermediate gear portion 115 makes 20 rotations, the second gear portion 113 makes one rotation. The drive gear 115 j is a toothless gear, and the driven gear 113 e engages with the toothless portion of the drive gear 115 j to have a non-drive section to which rotation is not transmitted. The cam portion 113c is a Geneva wheel consisting of a cam that divides the outer periphery into 20 equal parts, and the cam portion 115f has a locking element for restricting non-regular rotation of the above-mentioned Geneva wheel on the outer periphery, and the cam portion 115f and The cam portion 113c constitutes a Geneva mechanism of a division ratio 20 which is driven by the drive gear 115j and the driven gear 113e. The second gear portion 113 is intermittently driven by the Geneva mechanism. That is, when the drive gear 115 j rotates continuously, the second gear portion 113 rotates intermittently with the division ratio 20. The cam portion 115 f of the intermediate gear portion 115 engages with the cam portion 113 c of the second gear portion 113 to restrict the irregular rotation of the second gear portion 113 in the non-drive section of the drive gear 115 j.

  The gear 154b of the connection gear unit 154 meshes with the drive gear 113j of the second gear unit 113 to configure a transmission unit G4 having a gear ratio P4 of 1/2. That is, when the second gear portion 113 makes one rotation, the connecting gear portion 154 makes two rotations. The gear 154b of the connection gear unit 154 meshes with the driven gear 155e of the cooperative gear unit 155 to configure a transmission unit G5 having a gear ratio P5 of two. That is, when the communication gear portion 154 rotates twice, the interlocking gear portion 155 rotates once.

  The cam portion 155c of the cooperative gear portion 155 meshes with the cam portion 156f, which is a Geneva wheel of the fourth gear portion 156, to form a transmission portion G6 having a gear ratio P6 of two. That is, the fourth gear portion 156 makes one rotation when the cooperative gear portion 155 makes two rotations. The drive gear 155d is a toothless gear, and the driven gear 156e meshes with the toothless portion of the drive gear 155d to have a non-drive section to which rotation is not transmitted. The cam portion 156f is a Geneva wheel consisting of a cam that divides the outer circumference into two, and the cam portion 155c has a locking element for restricting non-regular rotation of the above-mentioned Geneva wheel on the outer circumference, and the cam portion 156f and The cam portion 155c constitutes a Geneva mechanism having a division ratio of 2 driven by the drive gear 155d and the driven gear 156e. The fourth gear portion 156 is intermittently driven by the Geneva mechanism. That is, when the interlocking gear portion 155 continuously rotates, the fourth gear portion 156 intermittently rotates at a division ratio of 2. The cam portion 155c of the cooperative gear portion 155 meshes with the cam portion 156f of the fourth gear portion 156, thereby restricting the irregular rotation of the fourth gear portion 156 in the non-drive section of the drive gear 155d.

  The cam portion 156c of the fourth gear portion 156 meshes with the cam portion 157c, which is a Geneva wheel of the fifth gear portion 157, to form a transmission portion G7 having a gear ratio P7 of two. That is, when the fourth gear portion 156 makes two revolutions, the fifth gear portion 157 makes one revolution. The drive gear 156d is a toothless gear, and the driven gear 156e meshes with the toothless portion of the drive gear 155d to have a non-drive section to which rotation is not transmitted. The cam portion 157c is a Geneva wheel consisting of a cam that divides the outer circumference into two equal parts, and the cam portion 156c has a locking element for restricting non-regular rotation of the above-mentioned Geneva wheel at one position on the outer circumference. The cam portion 156c constitutes a Geneva mechanism having a division ratio of 2 driven by the drive gear 156d and the driven gear 157e. The fifth gear portion 157 is intermittently driven by the Geneva mechanism. That is, when the fourth gear portion 156 is continuously rotated, the fifth gear portion 157 is intermittently rotated at a division ratio of 2. The cam portion 156c of the fourth gear portion 156 meshes with the cam portion 157c of the fifth gear portion 157 to restrict the irregular rotation of the fifth gear portion 157 in the non-drive section of the drive gear 156d.

  As the gears are connected in multiple stages as described above, when the second rotor 109 makes four revolutions, the fourth rotor 146 makes two revolutions and the fifth rotor 147 makes one revolution. Therefore, by detecting the rotations of the fourth rotor 146 and the fifth rotor 147, it is possible to specify the number of rotations of four rotations of the second rotor 109.

Next, the encoder 200 of the second embodiment configured as described above will be described.
The encoder 200 of the second embodiment is a first gear portion 112 that rotates integrally with the main shaft 8 and a gear that intermittently rotates when the first gear portion 112 continuously rotates, and is preset with respect to the first gear portion 112. The second gear part 113 and the second gear part 113, which are decelerated and rotated at the specified reduction ratio, are connected so as to sequentially halve the rotation amount of the second gear part 113, and intermittently rotated at the same rotational speed as the former stage when the former stage continuously rotates. The fourth gear portion 156 and the fifth gear portion 157, which are gears of stages to the Nth (N is an integer of 1 or more) stages, a first angle sensor 116 for detecting the rotation angle of the main shaft 8, and the second gear portion 113 And a fourth hole detector 161 and a fifth hole detector 162 for detecting the rotations of the gears of the first to N-th stages, respectively. According to this configuration, based on the output signals from the first angle sensor 116 and the second angle sensor 118 and the output signals from the fourth hole detector 161 and the fifth hole detector 162, multiple rotations of the main shaft 8 are performed. The amount of rotation can be specified. By providing the fourth hole detector 161 and the fifth hole detector 162, the specifiable range of the amount of rotation of the main shaft 8 can be expanded. Further, since the drive gear 155d, the driven gear 156e, the drive gear 156d, and the driven gear 157e have the same number of teeth (18 teeth) and rotate at the same speed, the passing speed of the gear decreases at the timing of detecting the rotation of each gear. Can be reduced to reduce fluctuations in detection timing of the fourth hole detector 161 and the fifth hole detector 162.

Third Embodiment
Subsequently, a third embodiment of the present invention will be described. In the drawings and the description of the third embodiment, the same or equivalent components and members as those of the second embodiment are denoted by the same reference numerals. The description overlapping with the second embodiment is appropriately omitted, and the configuration different from the second embodiment will be mainly described.
FIG. 12 is a schematic view showing the encoder 300. As shown in FIG. FIG. 13 is a front view showing the encoder 300. As shown in FIG. The encoder 300 differs from the encoder 200 in that the third specific element 74 is coupled to the front side of the second specific element 72 and the configuration of the gear train is different, and the other configuration is common.

  The third specific element 74 of the third embodiment is a mechanism for specifying the number of rotations of the first rotor 108 (= the number of rotations of the main shaft 8). The third specific element 74 is connected so as to sequentially halve the rotation amount of the first gear portion 117, and intermittently rotates at the same rotation speed as the former stage when the former stage is continuously rotated. And a rotation sensor for detecting the rotation of each of the first to N-th gears.

  The fourth rotor 146 is connected to the next stage of the first rotor 108. The fourth rotor 146 is intermittently rotated at a division ratio of 1/2 by rotation of the first rotor 108. The fifth rotor 147 intermittently rotates at a division ratio of 1/2 as the fourth rotor 146 rotates. Therefore, when the fifth rotor 147 makes one rotation and outputs an output signal of one cycle from the fifth hole detector 162, the fourth rotor 146 makes two rotations, and the output signal of two cycles from the fourth hole detector 161. The first rotor 108 makes four rotations and outputs a rotation angle signal of four cycles from the first angle sensor 116. Therefore, the number of rotations within 4 rotations of the first rotor 108 (hereinafter referred to as "the number of rotations of the first rotor 108") can be specified by the 2-bit parallel signal of the two 1-bit detection elements. Therefore, the number of rotations of the first rotor 108 that can be specified can be increased by increasing the number of connections (= N) of this 1-bit detection element.

  The second rotor 109 is connected to the rear stage of the fifth rotor 147 via a predetermined speed reduction mechanism. The second rotor 109 decelerates and rotates at a gear ratio P10 × P11 × P12, which will be described later, as the fifth rotor 147 rotates. Therefore, while the second rotor 109 rotates from 0 ° to 360 °, the second angle sensor 118 outputs a rotation angle signal corresponding to the number of rotations of the fifth rotor 147 within P10 × P11 × P12 rotation.

The fourth acquisition unit 47 acquires output signals from the fourth hole detector 161 and the fifth hole detector 162, arranges them into data of a predetermined format, and sends the data to the rotation number identification unit 45. The second acquisition unit 42 acquires the rotation angle signal from the second angle sensor 118, arranges it into data of a predetermined format, and sends it to the rotation speed identification unit 45. The rotation number identification unit 45 identifies the rotation number of the first rotor 108 based on the output data from the fourth acquisition unit 47, and identifies the rotation angle of the second rotor 109 based on the data from the second acquisition unit 42. The rotation number specifying unit 45 may specify the rotation number of the main shaft 8 by Equation 4 based on, for example, the rotation number of the first rotor 108 and the rotation angle of the second rotor 109.
(Expression 4) The number of revolutions of the main shaft 8 = 4 × P10 × P11 × P12 × rotation angle ÷ 360 ° of the second rotor 109
By substituting the rotational speed of the main shaft 8 into the above-mentioned equation 1, the amount of rotation of the main shaft 8 can be specified. The rotation amount specifying unit 44 specifies the rotation amount of the main shaft 8 based on the output data from the first acquisition unit 41 and the output data from the rotation number specifying unit 45. The output unit 46 outputs the amount of rotation of the spindle 8 specified by the amount-of-rotation specifying unit 44 in a predetermined format.

  Next, the detailed configuration of the encoder 300 according to the third embodiment will be described. FIG. 14 is a layout view of each gear portion of the encoder 300 as viewed from the second substrate 128 side. FIG. 15 is a layout view of each gear portion of the encoder 300 as viewed from the first substrate 126 side. FIG. 16 is a layout diagram of each angle sensor, each hole detector, and control unit 124 of the encoder 300 viewed from the first substrate 126 side. In addition, in FIGS. 14-16, description of one part gear part is abbreviate | omitted in order to understand easily.

  The encoder 300 includes a first gear portion 117, a fourth gear portion 151, a fifth gear portion 152, a communication gear portion 158, a linkage gear portion 159, and a second gear portion 119 as a reduction mechanism. The first gear portion 117, the fourth gear portion 151, the fifth gear portion 152, the connecting gear portion 158, the linkage gear portion 159, and the second gear portion 119 transmit rotation in this order. The first gear portion 117, the second gear portion 119, the fourth gear portion 151, and the fifth gear portion 152 of the encoder 300 are the first gear portion 112, the second gear portion 113, the fourth gear portion 156, and the fourth gear portion of the encoder 200. 5 corresponds to the gear portion 157.

  Six shafts rotatably supporting the first gear portion 117, the fourth gear portion 151, the fifth gear portion 152, the connecting gear portion 158, the cooperative gear portion 159, and the second gear portion 119 on the first substrate 126. (Not shown) is set up. At the central portion of each gear, a bearing (not shown) is provided which is fitted to the shaft via a gap. A rolling bearing or a sliding bearing may be used as this bearing.

  The first gear portion 117 includes a drive gear 117 d provided in order from the second substrate 128 side (top), and a cam portion 117 c. The drive gear 117 d and the cam portion 117 c each have a substantially cylindrical outer shape provided with predetermined unevenness or gear teeth on the outer peripheral surface. The drive gear wheel 117d and the cam portion 117c may be integrally formed, and may further have the same central axis. The driving gear wheel 117d is a missing tooth having a portion having 11 teeth at 11 consecutive positions among 22 equally divided positions on the outer periphery thereof, and a missing tooth portion which is a portion not provided with teeth at other places. It is a gear. That is, the drive gear 117 d is a toothless gear having gear teeth by 180 °.

  The fourth gear portion 151 includes a drive gear 151d, a cam portion 151c, a driven gear 151e, and a cam portion 151f, which are provided in order from the second substrate 128 side (upper side). The drive gear 151d, the cam portion 151c, the driven gear 151e, and the cam portion 151f each have a substantially cylindrical outer shape in which predetermined unevenness or gear teeth are provided on the outer peripheral surface. The drive gear 151d, the cam portion 151c, the driven gear 151e, and the cam portion 151f may be integrally formed, and may further have the same central axis. The driven gear 151e is a spur gear having 22 gear teeth at positions obtained by equally dividing the outer periphery thereof into 22. The drive gear 151 d is a missing tooth having a portion having 11 teeth at 11 consecutive positions among 22 equally divided positions on the outer periphery thereof, and a missing portion which is a portion not provided with a tooth at another portion. It is a gear. That is, the drive gear 151 d is a toothless gear having gear teeth by 180 °.

  The fifth gear portion 152 includes a gear 152 b and a cam portion 152 c which are provided in order from the second substrate 128 side (upper side). The gear 152b and the cam portion 152c each have a substantially cylindrical outer shape in which predetermined unevenness or gear teeth are provided on the outer peripheral surface. The gear 152b and the cam portion 152c may be integrally formed, and may further have the same central axis. The gear 152b is a spur gear having 22 gear teeth at positions equally divided into 22 on the outer periphery thereof.

  The contact gear portion 158 includes a driven gear 158 e, a cam portion 158 c and a drive gear 158 d, which are provided in order from the second substrate 128 side (upper side). The driven gear wheel 158e, the cam portion 158c, and the drive gear wheel 158d each have a substantially cylindrical outer shape in which predetermined unevenness or gear teeth are provided on the outer peripheral surface. The driven gear wheel 158e, the cam portion 158c and the drive gear wheel 158d may be integrally formed, and may further have the same central axis. The driven gear 158 e is a spur gear having 22 gear teeth at positions equally divided into 22 on the outer periphery thereof. The driving gear wheel 158d is a missing tooth having a portion having two teeth at two consecutive positions among the positions where the outer periphery is divided into 12 equal parts, and a missing tooth portion which is a portion where a tooth is not provided at other places. It is a gear. That is, the drive gearwheel 158d is a toothless gear having gear teeth by 60 °.

  The cooperative gear portion 159 includes a cam portion 159f, a driven gear 159e, a cam portion 159c, and a drive gear 159d, which are provided in order from the second substrate 128 side (upper side). The cam portion 159f, the driven gear 159e, the cam portion 159c, and the drive gear 159d each have a substantially cylindrical outer shape in which predetermined unevenness or gear teeth are provided on the outer peripheral surface. The cam portion 159f, the driven gear 159e, the cam portion 159c, and the drive gear 159d may be integrally formed, and may further have the same central axis. The driven gear 159e is a spur gear having 48 gear teeth at positions obtained by equally dividing the outer periphery thereof into 48. The drive gear 159d is a missing tooth having a portion having two teeth at two consecutive positions among the positions where the outer periphery is divided into 12 equal parts, and a missing tooth portion which is a portion where no teeth are provided at other places. It is a gear. That is, the drive gear 159 d is a toothless gear having gear teeth by 60 °. The cam portion 159f has an 18-tooth, substantially petal-like cam surface on its outer periphery.

  The second gear portion 119 includes a cam portion 119c and a driven gear 119e provided in order from the second substrate 128 side (upper side). The cam portion 119c and the driven gear 119e each have a substantially cylindrical outer shape provided with predetermined unevenness or gear teeth on the outer peripheral surface. The cam portion 119c and the driven gear 119e may be integrally formed, and may further have the same central axis. The driven gear 119e is a spur gear having 60 gear teeth at positions equally divided by 60 on the outer periphery thereof. The cam portion 119c has an approximately petal-like cam surface of 20 teeth on its outer periphery.

  The cam portion 117c of the first gear portion 117 meshes with the vane wheel 151f of the fourth gear portion 151 to configure a transmission portion G8 having a gear ratio P8 of two. That is, when the first gear portion 117 rotates twice, the fourth gear portion 151 rotates once. The drive gear 117d is a toothless gear, and the driven gear 151e meshes with the toothless portion of the drive gear 117d so as to have a non-drive section to which rotation is not transmitted. The cam portion 151f is a Geneva wheel consisting of a cam that divides the outer circumference into two, and the cam portion 117c has a locking element for restricting non-regular rotation of the above-mentioned Geneva wheel on the outer circumference, and the cam portion 151f and The cam portion 117c constitutes a Geneva mechanism having a division ratio of 2 driven by the drive gear 117d and the driven gear 151e. The fourth gear portion 151 is intermittently driven by the Geneva mechanism. That is, when the drive gear 117 d rotates continuously, the fourth gear portion 151 rotates intermittently with the division ratio 2. The cam portion 117c of the first gear portion 117 engages with the cam portion 151f of the fourth gear portion 151 to restrict the irregular rotation of the fourth gear portion 151 in the non-drive section of the drive gear 117d.

  The cam portion 151c of the fourth gear portion 151 meshes with the cam portion 152c, which is a Geneva wheel of the fifth gear portion 152, to form a transmission portion G9 having a gear ratio P9 of two. That is, when the fourth gear portion 151 makes two revolutions, the fifth gear portion 152 makes one revolution. The drive gear 151 d is a toothless gear, and the gear 152 b meshes with the toothless portion of the drive gear 151 d to have a non-drive section to which rotation is not transmitted. The cam portion 152c is a Geneva wheel consisting of a cam that divides the outer circumference into two, and the cam portion 151c has a locking element for restricting non-regular rotation of the above-mentioned Geneva wheel on the outer circumference, and the cam portion 152c and The cam portion 151c constitutes a Geneva mechanism having a division ratio of 2 driven by the drive gear 151d and the gear 152b. The fifth gear portion 152 is intermittently driven by the Geneva mechanism. That is, when the drive gear 151 d is continuously rotated, the fifth gear portion 152 is intermittently rotated at a division ratio of 2. The cam portion 151c of the fourth gear portion 151 engages with the cam portion 152c of the fifth gear portion 152 to restrict the irregular rotation of the fifth gear portion 152 in the non-drive section of the drive gear 151d.

  The gear 152b of the fifth gear portion 152 meshes with the driven gear 158e of the communication gear portion 158 to form a transmission portion G10 having a gear ratio P10 of one. That is, when the fifth gear portion 152 makes one rotation, the communication gear portion 158 makes one rotation.

  The cam portion 158 c of the connecting gear portion 158 meshes with the cam portion 159 f which is a Geneva wheel of the cooperative gear portion 159 to configure a transmission portion G 11 having a gear ratio P 11 of 18. That is, when the connecting gear portion 158 rotates 18 times, the interlocking gear portion 159 rotates 1 turn. The drive gear 158d is a toothless gear, and the driven gear 159e meshes with the toothless portion of the drive gear 158d to have a non-drive section to which rotation is not transmitted. The cam portion 159f is a Geneva wheel consisting of a cam that divides the outer circumference into 18 equal parts, and the cam portion 158c has a locking element for restricting the non-regular rotation of the above-mentioned Geneva wheel on the outer circumference. The cam portion 158c constitutes a Geneva mechanism having a division ratio 18 which is driven by the drive gear 158d and the driven gear 159e. The cooperative gear unit 159 is intermittently driven by the Geneva mechanism. That is, when the drive gear 151 d rotates continuously, the linkage gear unit 159 rotates intermittently with the division ratio 18. The cam portion 158c of the connecting gear portion 158 meshes with the cam portion 159f of the interlocking gear portion 159, thereby restricting the irregular rotation of the interlocking gear portion 159 in the non-drive section of the drive gear 158d.

  The cam portion 159c of the cooperative gear portion 159 meshes with the cam portion 119c, which is a Geneva wheel of the second gear portion 119, to form a transmission portion G12 having a gear ratio P12 of 20. That is, when the interlocking gear portion 159 rotates 20 times, the second gear portion 119 rotates once. The drive gear 159d is a toothless gear, and the driven gear 119e meshes with the toothless portion of the drive gear 159d to have a non-drive section to which rotation is not transmitted. The cam portion 119c is a Geneva wheel consisting of a cam that divides the outer circumference into 20 equal parts, and the cam portion 159c has a locking element for restricting non-regular rotation of the above-mentioned Geneva wheel at one position on the outer circumference. The cam portion 159c constitutes a Geneva mechanism having a division ratio of 20 driven by the drive gear 159d and the driven gear 119e. The second gear portion 119 is intermittently driven by the Geneva mechanism. That is, when the interlocking gear portion 159 continuously rotates, the second gear portion 119 intermittently rotates with the division ratio 20. The cam portion 159c of the cooperative gear portion 159 meshes with the cam portion 119c of the second gear portion 119 to restrict the irregular rotation of the second gear portion 119 in the non-drive section of the drive gear 159d.

  As the second gear portion 119 and the second rotor 109 make one rotation by the multistage connection of the respective gear portions as described above, the interlocking gear portion 159 makes 20 rotations, and the communication gear portion 158 makes 360 rotations. The fifth gear portion 152 and the fifth rotor 147 rotate 360 degrees, the fourth gear portion 151 and the fourth rotor 146 rotate 720, and the first gear portion 117, the first rotor 108, and the main shaft 8 rotate 1440. By detecting the rotations of the second rotor 109, the fourth rotor 146, and the fifth rotor 147, it is possible to specify the number of rotations within the range of 1440 rotations of the main shaft 8.

Next, features of the encoder 300 according to the third embodiment configured as described above will be described.
The encoder 300 of the third embodiment is connected so as to sequentially halve the amount of rotation of the first gear portion 117, which rotates integrally with the main shaft 8, and the first gear portion 117, and when the former rotates continuously, the same rotation as the former The fourth gear portion 151 and the fifth gear portion 152, which are gears of the first to N-th (N is an integer of 1 or more) steps intermittent rotation at a speed, and the fifth gear portion 152, which is the gear of the Nth stage A second gear portion 119 that is a gear that intermittently rotates when continuously rotating, and is connected to the fifth gear portion 152 at a first reduction ratio, and a first angle sensor 116 that detects a rotation angle of the main shaft 8; The fourth hole detector 161 and the fifth hole detector 162, which are rotation sensors for detecting the rotation of the first to N-th gears, and the second angle sensor 118 for detecting the rotation angle of the second gear portion 119. And. According to this configuration, based on the output signals from the first angle sensor 116 and the second angle sensor 118 and the output signals from the fourth hole detector 161 and the fifth hole detector 162, multiple rotations of the main shaft 8 are performed. The amount of rotation can be specified. By providing the fourth hole detector 161 and the fifth hole detector 162, the specifiable range of the amount of rotation of the main shaft 8 can be expanded. Further, the fourth gear portion 151 and the fifth gear portion 152, which have the same number of teeth (22 teeth) and rotate at the same speed, the drive gear 117d, the driven gear 151e, the drive gear 151d, and the gear 152b are the second gear. By being provided on the front side of the part 119, it is possible to suppress the decrease in the passing speed of the gear at the timing of detecting the rotation of each gear, and to change the detection timing of the fourth hole detector 161 and the fifth hole detector 162. At the same time, the circumferential speed on the input side can be increased and the influence of backlash can be suppressed.

  The above has been described based on several embodiments of the present invention. These embodiments are illustrative, and it is understood by those skilled in the art that various modifications and changes are possible within the scope of the claims of the present invention, and such variations and modifications are also within the scope of the claims of the present invention. It is about to be Accordingly, the descriptions and drawings herein are to be considered as illustrative and not restrictive.

  Hereinafter, modified examples will be described. In the description of the modified examples, the same reference numerals are used for components, parts, and members that are the same as or equivalent to those of the embodiment. Further, the description overlapping with the embodiment is appropriately omitted, and the configuration different from the embodiment will be mainly described.

(Modification 1)
In the first to third embodiments, although an example in which a toothless gear having gear teeth by 180 °, 60 ° or 36 ° is used to realize intermittent driving has been described, the present invention is not limited thereto. Intermittent drive may be realized by a mechanism based on another principle. For example, the intermittent drive may be realized by a Geneva mechanism using a drive pin and a cam groove.
In the second and third embodiments, the gear ratio of the fourth rotor and the fifth rotor has been described as 1/2, but the drive gear and the driven gear have the same rotational speed with the same number of teeth of the drive gear and the driven gear. Even if the number of divisions of the Geneva wheel is made larger than 2, the same effect as in the case of the gear ratio 1/2 is obtained.

(Modification 2)
In the second and third embodiments, an example in which the rotation sensor is a magnetic sensor using a Hall effect has been described, but the present invention is not limited thereto. The rotation sensor may be based on another principle as long as it can detect rotation. For example, the rotation sensor may be an optical or capacitive sensor.

(Modification 3)
In the first to third embodiments, an example is described in which the encoder 100 is configured of five sets of gear portions, the encoder 200 is configured of seven sets of gear portions, and the encoder 300 is configured of six sets of gear portions. It is not limited. The number of gear parts may be increased or decreased as needed.

(Modification 4)
In the first to third embodiments, although an example in which the respective gear portions are linearly arranged has been described, the present invention is not limited to this. For example, each gear portion may be arranged annularly or spirally.

(Other modifications)
In the first to third embodiments, the shaft is erected on the first substrate 126, and the bearing provided on the gear portion is fitted to the shaft. However, the present invention is not limited to this. A shaft may be fixed to each gear portion, and this shaft may be configured to be fitted to a bearing provided on the first substrate 126. In the second and third embodiments, N is described as an integer of 1 or more, but N may be an integer of 2 or more.

  Any combination of the above-described embodiment and the modification is also useful as an embodiment of the present invention. The new embodiments resulting from the combination combine the effects of each of the combined embodiments and variations.

  In the drawings used for the description, hatching is applied to some members in order to clarify the relationship between the members, but the hatching does not limit the material or material of these members.

  100, 200, 300 · · · · · · · · · · · · · · · · 1st rotor, 109 · · 2nd rotor, 110 · · 3rd rotor, 112 · · 1st gear portion, 113 · · 2nd gear portion , 114: third gear part 116: first angle sensor 118: second angle sensor 119: second gear part 120: third angle sensor 146: fourth rotor 147: The fifth rotor 156 the fourth gear portion 161 the fourth hole detector 162 the fifth hole detector.

Claims (2)

An absolute encoder for detecting an amount of rotation based on a rotation angle and a number of rotations over a plurality of rotations of a spindle.
A first gear portion provided on the main shaft and integrally rotating;
A gear portion meshing with the first gear portion that rotates continuously and intermittently rotating, and a second gear portion that rotates at a speed reduction ratio determined in advance with respect to the first gear portion;
The first to N-th (N is an integer of 2 or more) stages of gears connected so as to sequentially decrease the amount of rotation of the second gear portion and intermittently rotate at the same rotational speed as the former stage when the former stage continuously rotates ,
A first magnetic angle sensor for detecting a rotation angle of the first gear portion;
A second magnetic angle sensor for detecting a rotation angle of the second gear portion;
A rotation sensor that detects rotation of each of the first to N-th gears;
Rotation angle and rotation speed of the front Symbol spindle, wherein a rotation angle of the first gear unit, the a rotation angle of the second gear unit, and the rotation angle of the gear, respectively the first stage to N-th stage, in the identified Absolute encoder characterized by   The rotation sensor of the Nth stage among the rotation sensors is a magnetic angle sensor having a resolution higher than the resolution of the rotation sensor of the (N−1) th stage among the rotation sensors. Absolute encoder as described in.

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