JP7051978B2 - Absolute encoder - Google Patents

Description

The present invention relates to an absolute encoder for specifying the amount of rotation of an input shaft.

Conventionally, rotary encoders used for detecting the position and angle of a movable element in various control mechanical devices are known. Such encoders include incremental encoders that detect relative positions or angles, and absolute encoders that detect absolute positions or angles. For example, Patent Document 1 describes an absolute type for digitally measuring the amount of rotation of a rotary shaft for motion control of an automatic control device or a robot device or a rotary shaft for power transmission used for opening and closing a valve as an absolute amount. The rotary encoder is described.

Jikkenhei 4-96019 Gazette

The absolute encoder described in Patent Document 1 is configured by stacking components such as a rotating disk, a slit, a light emitting element, and a light receiving element in the axial direction of the shaft. Therefore, since the axial dimensions of the components are stacked in the axial direction, the axial dimensions of the absolute encoder become large, and there is a problem that it is difficult to reduce the thickness. In order to make the absolute encoder thinner, it is conceivable to make each component thin. However, if the components are formed thin, the strength is lowered, and there is a possibility that the components are easily damaged when subjected to vibration or impact.

The present invention has been made in view of such problems, and an object of the present invention is to provide an absolute encoder suitable for thinning.

In order to solve the above problems, the absolute encoder according to an aspect of the present invention is an absolute encoder that specifies a rotation amount over a plurality of rotations of the spindle, and is a first drive gear that rotates according to the rotation of the spindle and a first. The first driven gear that meshes with the drive gear, the second driven gear that rotates according to the rotation of the first driven gear, the second driven gear that meshes with the second drive gear, and the second driven gear that rotates according to the rotation of the second driven gear. It is equipped with an angle sensor that detects the rotation angle of the rotating body.

According to this aspect, in the absolute encoder, the angle of rotation of the second driven gear can be detected by the angle sensor.

Another aspect of the invention is also an absolute encoder. This absolute encoder is an absolute encoder that specifies the amount of rotation over a plurality of rotations of the spindle, and is an intermediate rotating body that rotates at the first reduction ratio with the rotation of the spindle and a second deceleration with the rotation of the intermediate rotating body. A second rotating body that rotates at a ratio and an angle sensor that detects the rotation angle of the second rotating body are provided. The rotation axis of the main shaft is in a twisted position with respect to the rotation axis of the intermediate rotating body, and is provided parallel to the rotation axis of the second rotating body.

Yet another aspect of the invention is also an absolute encoder. This absolute encoder is an absolute encoder that specifies the amount of rotation over multiple rotations of the spindle, including a worm transmission mechanism, a deceleration mechanism that rotates the magnet with the rotation of the spindle, and a magnet according to the magnetic poles of the magnet. It is equipped with an angle sensor that detects the angle of rotation. The rotation axis of the spindle is parallel to the rotation axis of the magnet.

It should be noted that any combination of the above components or components or expressions of the present invention that are mutually replaced between methods, devices, systems, etc. are also effective as aspects of the present invention.

According to the present invention, it is possible to provide an absolute encoder suitable for thinning.

It is a block diagram explaining the encoder which concerns on 1st Embodiment of this invention. It is a block diagram explaining the encoder which concerns on 2nd Embodiment of this invention. It is a block diagram explaining the encoder which concerns on 3rd Embodiment of this invention. It is a block diagram explaining the encoder which concerns on 4th Embodiment of this invention. It is a perspective view of the encoder of FIG. It is another perspective view of the encoder of FIG. It is still another perspective view of the encoder of FIG. It is a bottom view of the board of the encoder of FIG. It is a top view of the encoder of FIG. It is a front view including a partial cross section of the encoder of FIG. It is sectional drawing which shows the periphery of the 2nd rotating body of the encoder of FIG. It is sectional drawing which shows the periphery of the 3rd rotating body and the connecting rotating body of the encoder of FIG. It is a top view of the encoder which concerns on 5th Embodiment of this invention. It is a front view which includes the partial cross section of the encoder which concerns on 5th Embodiment of this invention. It is a top view of the encoder which concerns on 6th Embodiment of this invention. It is a front view which includes the partial cross section of the encoder which concerns on 6th Embodiment of this invention. It is a top view of the encoder which concerns on 7th Embodiment of this invention. It is a front view which includes the partial cross section of the encoder which concerns on 7th Embodiment of this invention. It is a top view of the encoder which concerns on 8th Embodiment of this invention. It is a specification classification table of an encoder according to each embodiment.

The present inventor has obtained the following findings regarding an absolute encoder (hereinafter, simply referred to as an encoder).

The present inventor obtains the rotation amount (hereinafter referred to as the rotation amount of the spindle) over a plurality of rotations of the spindle (hereinafter referred to as a plurality of rotations) and the rotation angle of the rotating body that decelerates and rotates with the rotation of the spindle. By doing so, we found that it could be identified. That is, the amount of rotation of the spindle can be specified by dividing the rotation angle of the rotating body by the reduction ratio. Here, the range of the amount of rotation of the main shaft that can be specified increases in inverse proportion to the reduction ratio. For example, if the reduction ratio is 1/100, the amount of rotation for 100 rotations can be specified. On the other hand, the resolution of the amount of rotation of the identifiable spindle decreases in inverse proportion to the reduction ratio. For example, if the reduction ratio is 1/100, the resolution that was 0.1 ° when the reduction ratio is 1 is reduced to 10 °.

Based on this knowledge, the present inventor has devised a configuration of an encoder in which the rotation amount range and the resolution can be selected according to the application. In this case, the balance between cost and performance can be improved. Hereinafter, a specific configuration will be described based on some embodiments.

Hereinafter, the present invention will be described with reference to each drawing based on a preferred embodiment. In each embodiment and modification, the same or equivalent components and members are designated by the same reference numerals, and redundant description will be omitted as appropriate. Further, the dimensions of the members in each drawing are shown in an appropriately enlarged or reduced size for easy understanding. In addition, some of the members that are not important for explaining the embodiment in each drawing are omitted and displayed.
Also, terms including ordinal numbers such as 1st and 2nd are used to describe various components, but this term is used only for the purpose of distinguishing one component from other components, and this term is used. The components are not limited by.

[First Embodiment]
The first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a block diagram illustrating an encoder 100 according to the first embodiment of the present invention. The encoder 100 is an absolute encoder that specifies the amount of rotation over a plurality of rotations of the spindle 1a of the motor 1. The encoder 100 includes a spindle 1a, a first rotating body 20, a first worm gear 10, a first worm wheel 12, an intermediate rotating body 22, a second worm gear 14, a second worm wheel 16, and a second. It includes a two-rotating body 24, a magnet Mp, an angle sensor Sp, and a control unit 40.

The spindle 1a is an output shaft of the motor 1 and is an input shaft to which rotation is input to the encoder 100. The first rotating body 20 is fixed to the spindle 1a and is rotatably supported by the bearing member of the motor 1 integrally with the spindle 1a. The first worm gear 10 is provided on the outer periphery of the first rotating body 20 so that both central axes substantially coincide with each other so that the first worm gear 10 rotates according to the rotation of the main shaft 1a. The first worm wheel 12 is provided so as to mesh with the first worm gear 10 and rotate with the rotation of the first worm gear 10. The first worm wheel 12 is provided so that the central axis coincides with the outer circumference of the intermediate rotating body 22. The axis angle between the first worm wheel 12 and the first worm gear 10 is set to 90 °.

The outer diameter of the first worm wheel 12 is not particularly limited, but in the example of this figure, the outer diameter of the first worm wheel 12 is set to be smaller than the outer diameter of the first worm gear 10. Compared with the case where the outer diameter of the first worm wheel 12 is large, the dimension in the axial direction with respect to the main shaft 1a of the encoder can be suppressed to be small.

The second worm gear 14 rotates according to the rotation of the first worm wheel 12. The second worm gear 14 is provided on the outer periphery of the intermediate rotating body 22 so that both central axes substantially coincide with each other. The second worm wheel 16 is provided so as to mesh with the second worm gear 14 and rotate with the rotation of the second worm gear 14. The second worm wheel 16 is provided on the outer periphery of the second rotating body 24 so that both central axes substantially coincide with each other. The axis angle between the second worm wheel 16 and the second worm gear 14 is set to 90 °. The rotation axis of the second worm wheel 16 is provided parallel to the rotation axis of the first worm gear 10.

The angle sensor Sp detects the angle of rotation of the second worm wheel 16. The magnet Mp is fixed to the upper surface of the second rotating body 24 so that both central axes are substantially aligned with each other. A two-pole magnetic pole Up is provided on the upper surface of the magnet Mp in a direction perpendicular to the rotation axis of the second rotating body 24. The angle sensor Sp is provided so that its lower surface faces the upper surface of the magnet Mp via a gap in the thrust direction. As an example, the angle sensor Sp is fixed to a substrate supported by a housing (not shown) of the encoder 100 or the like. The angle sensor Sp detects the magnetic pole Up, identifies the rotation angle of the magnet Mp according to the magnetic pole Up, and outputs the rotation angle to the control unit 40. The control unit 40 identifies and outputs the rotation amount of the spindle 1a based on the rotation angle acquired from the angle sensor Sp. As an example, the control unit 40 may output the rotation amount of the spindle 1a as a digital signal.

The number of threads of the first worm gear 10 is 1, and the number of teeth of the first worm wheel 12 is 20. That is, the first worm gear 10 and the first worm wheel 12 constitute the first worm transmission mechanism 11 having a reduction ratio of 1/20. When the first worm gear 10 rotates 20 times, the first worm wheel 12 makes one rotation. The first worm wheel 12 rotates the intermediate rotating body 22, and the intermediate rotating body 22 rotates the second worm gear 14. Therefore, when the first worm wheel 12 makes one rotation, the intermediate rotating body 22 and the second worm gear 14 make one rotation.

The number of threads of the second worm gear 14 is 5, and the number of teeth of the second worm wheel 16 is 25. That is, the second worm gear 14 and the second worm wheel 16 form a second worm transmission mechanism 15 having a reduction ratio of 1/5. When the second worm gear 14 makes five rotations, the second worm wheel 16 makes one rotation. The second worm wheel 16 rotates the second rotating body 24 and the magnet Mp. Due to the action of each rotating body of each of these gears, when the spindle 1a rotates 100 times, the intermediate rotating body 22 rotates 5 times and the magnet Mp rotates once. That is, the angle sensor Sp can specify the amount of rotation for 100 rotations of the spindle 1a.

The encoder 100 configured in this way can specify the amount of rotation of the spindle 1a. As an example, when the spindle 1a makes one rotation, the second rotating body 24 and the magnet Mp rotate 1/100 rotation, that is, 3.6 °. Therefore, if the rotation angle of the second rotating body 24 is 3.6 ° or less, it can be specified that the spindle 1a has a rotation amount within one rotation.

[Second Embodiment]
The encoder 120 according to the second embodiment of the present invention will be described with reference to FIG. FIG. 2 is a block diagram illustrating an encoder 120 according to a second embodiment of the present invention. The encoder 120 is an absolute encoder that specifies the amount of rotation over a plurality of rotations of the spindle 1a of the motor 1. The encoder 120 further includes an angle sensor Sq and a magnet Mq with respect to the encoder 100 according to the first embodiment, and the other configurations are the same. The description that overlaps with the first embodiment will be omitted, and the different configurations will be described.

The magnet Mq is fixed to the upper surface of the first rotating body 20 so that both central axes are substantially aligned with each other. A two-pole magnetic pole Uq is provided on the upper surface of the magnet Mq in a direction perpendicular to the rotation axis of the first rotating body 20. The angle sensor Sq is provided so that its lower surface faces the upper surface of the magnet Mq via a gap in the thrust direction. As an example, the angle sensor Sq is fixed to a substrate on which the angle sensor Sp is fixed on the same surface as the angle sensor Sp. The angle sensor Sq detects the magnetic pole Uq, identifies the rotation angle of the magnet Mq, which is the rotation angle of the spindle 1a, according to the magnetic pole Uq, and outputs the rotation angle to the control unit 40. The control unit 40 specifies the rotation angle of the spindle 1a based on the rotation angle acquired from the angle sensor Sq. The resolution of the rotation angle of the spindle 1a corresponds to the resolution of the angle sensor Sq.

The encoder 120 configured in this way specifies the amount of rotation of the spindle 1a over a plurality of rotations according to the rotation angle detected by the angle sensor Sp, and also specifies the amount of rotation of the spindle 1a according to the rotation angle detected by the angle sensor Sq. The rotation angle can be specified. As a result, it is possible to expand the range of the rotation amount of the identifiable spindle 1a and improve the resolution of the rotation angle of the identifiable spindle at the same time.

[Third Embodiment]
The encoder 140 according to the third embodiment of the present invention will be described with reference to FIG. FIG. 3 is a block diagram illustrating an encoder 140 according to a third embodiment of the present invention. The encoder 140 is an absolute encoder that specifies the amount of rotation over a plurality of rotations of the spindle 1a of the motor 1. The encoder 140 has a third worm gear 30, a third worm wheel 32, a connecting rotating body 33, a driving gear 34, a driven gear 36, and a third rotating body 38 with respect to the encoder 100 according to the first embodiment. The magnet Mr and the angle sensor Sr are further included, and the other configurations are the same. The description that overlaps with the first embodiment will be omitted, and the different configurations will be described.

The third worm gear 30 rotates according to the rotation of the first worm wheel 12. The third worm gear 30 is provided on the outer periphery of the intermediate rotating body 22 so that both central axes substantially coincide with each other. The third worm wheel 32 is provided so as to mesh with the third worm gear 30 and rotate with the rotation of the third worm gear 30. The third worm wheel 32 is provided on the outer periphery of the connecting rotating body 33 so that both central axes substantially coincide with each other. The axis angle between the third worm wheel 32 and the third worm gear 30 is set to 90 °. The rotation axis of the third worm wheel 32 is provided parallel to the rotation axis of the first worm gear 10.

The drive gear 34 is fixed to the outer periphery of the connecting rotating body 33 so that the central axes of both the third worm wheel 32 and the third worm wheel 32 substantially coincide with each other. The drive gear 34 rotates integrally according to the rotation of the third worm wheel 32. The driven gear 36 meshes with the drive gear 34 and rotates according to the rotation of the drive gear 34. The third rotating body 38 is fixed to the driven gear 36 so that both central axes are substantially aligned with each other. The third rotating body 38 rotates integrally according to the rotation of the driven gear 36. The rotation axis of the third rotating body 38 is provided in parallel with the rotation axis of the first rotating body 20.

The number of threads of the third worm gear 30 is 1, and the number of teeth of the third worm wheel 32 is 30, which constitutes the third worm transmission mechanism 31 having a reduction ratio of 1/30. When the third worm gear 30 makes 30 rotations integrally with the intermediate rotating body 22, the third worm wheel 32 makes one rotation. That is, when the spindle 1a rotates 600 times, the third worm wheel 32 makes one rotation. The drive gear 34 is a spur gear having 24 teeth, and the driven gear 36 is a spur gear having 40 teeth, which constitute a reduction mechanism 35 having a reduction ratio of 3/5. That is, when the spindle 1a rotates 1000 times, the driven gear 36 and the third rotating body 38 make one rotation integrally.

The angle sensor Sr detects the angle of rotation of the driven gear 36. The magnet Mr is fixed to the upper surface of the third rotating body 38 so that both central axes are substantially aligned with each other. A two-pole magnetic pole Ur is provided on the upper surface of the magnet Mr in a direction perpendicular to the rotation axis of the third rotating body 38. The angle sensor Sr is provided so that its lower surface faces the upper surface of the magnet Mr through a gap in the thrust direction. As an example, the angle sensor Sr is fixed to a substrate on which the angle sensor Sp is fixed on the same surface as the angle sensor Sp. The angle sensor Sr detects the magnetic pole Ur, identifies the rotation angle of the magnet Mr, which is the rotation angle of the third rotating body 38 and the driven gear 36, according to the magnetic pole Ur, and outputs the rotation angle to the control unit 40.

Due to the action of each rotating body of each of these gears, when the spindle 1a rotates 1000 times, the third rotating body 38, the driven gear 36, and the magnet Mr make one rotation. That is, the angle sensor Sr can specify the amount of rotation for 1000 rotations of the spindle 1a. The control unit 40 specifies the amount of rotation of the spindle 1a based on each rotation angle acquired from the angle sensor Sp and the angle sensor Sr. As an example, when the spindle 1a makes one rotation, the driven gear 36 and the magnet Mr rotate 1/1000, that is, 0.36 °. Therefore, if the rotation angle of the driven gear 36 is 0.36 ° or less, it can be specified that the spindle 1a has a rotation amount within one rotation.

The encoder 140 of the third embodiment configured as described above can specify the rotation amount of the spindle 1a by specifying the rotation amount over a plurality of rotations of the spindle 1a according to the rotation angle detected by the angle sensor Sr. The range of can be further increased. The encoder 140 specifies the amount of rotation of the spindle 1a over a plurality of rotations according to the rotation angle detected by the angle sensor Sp, so that the amount of rotation of the spindle 1a that can be specified is specified as compared with the case where the angle sensor Sp is not provided. It is possible to suppress a decrease in the resolution of the.

As a result, the encoder 140 can compensate for the decrease in the resolution of the identifiable spindle rotation amount while further expanding the range of the identifiable spindle rotation amount.

[Fourth Embodiment]
The encoder 160 according to the fourth embodiment of the present invention will be described with reference to FIG. FIG. 4 is a block diagram illustrating an encoder 160 according to a fourth embodiment of the present invention. The encoder 160 is an absolute encoder that specifies the amount of rotation over a plurality of rotations of the spindle 1a of the motor 1. The encoder 160 includes an angle sensor Sq, a magnet Mq, a third worm gear 30, a third worm wheel 32, a connecting rotary body 33, and a drive gear 34 with respect to the encoder 100 according to the first embodiment. The driven gear 36, the third rotary body 38, the magnet Mr, and the angle sensor Sr are further included, and the other configurations are the same. That is, the encoder 160 includes the configurations of the encoder 100 according to the first embodiment, the encoder 120 according to the second embodiment, and the encoder 140 according to the third embodiment. The description that overlaps with the first to third embodiments will be omitted, and the different configurations will be described.

The control unit 40 specifies the amount of rotation of the spindle 1a based on each rotation angle acquired from the angle sensors Sp, Sq, and Sr.

The encoder 160 of the fourth embodiment configured in this way specifies the amount of rotation of the spindle 1a over a plurality of rotations according to the rotation angle detected by the angle sensor Sr, so that the amount of rotation of the spindle 1a can be specified. The range of can be further increased. The encoder 160 specifies the amount of rotation of the spindle 1a over a plurality of rotations according to the rotation angle detected by the angle sensor Sp, so that the amount of rotation of the spindle 1a that can be specified is specified as compared with the case where the angle sensor Sp is not provided. It is possible to suppress a decrease in the resolution of the. The encoder 160 can improve the resolution of the identifiable rotation angle of the spindle 1a by specifying the rotation angle of the spindle 1a according to the rotation angle detected by the angle sensor Sq.

As a result, the encoder 160 can improve the resolution of the rotation angle of the identifiable spindle while further expanding the range of the rotation amount of the identifiable spindle 1a.

Next, a detailed configuration of the encoder 160 according to the fourth embodiment will be described with reference to FIGS. 5 to 12. The following description is similarly applied to the encoders 100, 120, 140 of the first to third embodiments with respect to the configuration common to the encoder 160.

FIG. 5 is a perspective view of the encoder 160 according to the fourth embodiment. Hereinafter, the description will be given based on the XYZ Cartesian coordinate system. The X-axis direction corresponds to the horizontal left-right direction, the Y-axis direction corresponds to the horizontal front-back direction, and the Z-axis direction corresponds to the vertical vertical direction. The Y-axis direction and the Z-axis direction are orthogonal to the X-axis direction, respectively. The X-axis direction may be expressed as left or right, the Y-axis direction as forward or backward, and the Z-axis direction as upward or downward. In this figure, a state viewed from above in the Z-axis direction is referred to as a plan view, a state viewed from the front in the Y-axis direction is referred to as a front view, and a state viewed from the left and right in the X-axis direction is referred to as a side view. The notation in such a direction does not limit the posture in which the encoder 160 is used, and the encoder 160 can be used in any posture.

As described above, the encoder 160 is an absolute type encoder that specifies and outputs the amount of rotation over a plurality of rotations of the spindle of the motor 1. In this example, the encoder 160 is provided at the end of the motor 1 in the Z-axis direction. The shape of the encoder 160 is not particularly limited, but in the embodiment, the encoder 160 has a substantially rectangular shape in a plan view, and the extension direction of the main axis (hereinafter referred to as an axial direction) in the front view and the side view. The axial direction is parallel to the Z-axis direction.) It has a thin horizontally long rectangular shape. That is, the encoder 160 has a rectangular parallelepiped shape that is flat in the Z-axis direction.

The encoder 160 includes a hollow square cylindrical housing 3 that houses the internal structure. The housing 3 includes at least a plurality of (for example, four) outer wall portions 3b, 3c, 3d, and 3e that surround the spindle and the intermediate rotating body. The lid portion 4 is fixed to the end portions of the outer wall portions 3b, 3c, 3d, and 3e of the housing 3. The lid portion 4 has a substantially rectangular shape in a plan view, and is a plate-shaped member thin in the axial direction. The outer wall portions 3b, 3c, 3d, and 3e are connected in this order. The outer wall portions 3b and 3d are provided in parallel with each other. The outer wall portions 3c and 3e are bridged over the side end portions of the outer wall portions 3b and 3d and are provided in parallel with each other. In this example, the outer wall portions 3b and 3d are stretched in the X-axis direction in a plan view, and the outer wall portions 3c and 3e are stretched in the Y-axis direction in a plan view.

As an example, the motor 1 may be a stepping motor or a DC brushless motor. As an example, the motor 1 may be applied as a drive source for driving a robot for industrial use or the like via a reduction mechanism such as a strain wave gearing device. The spindle 1a of the motor 1 projects on both sides of the motor 1 in the Z-axis direction. The encoder 160 outputs the amount of rotation of the spindle 1a as a digital signal.

FIG. 6 is another perspective view of the encoder 160. FIG. 6 shows a state in which the lid 4 is removed from the housing 3. In this state, the substrate 5 is provided so as to cover the inside of the encoder. The substrate 5 is a printed wiring board having a substantially rectangular shape in a plan view and having a thin plate shape in the axial direction. FIG. 7 is still another perspective view of the encoder 160. FIG. 8 is a bottom view of the substrate 5. FIG. 9 is a plan view of the encoder 160. 7 and 9 show a state in which the substrate 5 is removed. Although the angle sensors Sp, Sq, and Sr are attached to the substrate 5, the angle sensors Sp, Sq, and Sr are displayed in these figures for easy understanding. FIG. 10 is a front view of the encoder 160. FIG. 10 shows a state in which the encoder 160 is cut along a plane parallel to the Z-axis direction passing through the center of the spindle 1a. FIG. 11 is a cross-sectional view showing the periphery of the second rotating body 24. FIG. 11 shows a vertical cross section of the encoder 160 as viewed from substantially the left side. FIG. 11 shows a state in which the encoder 160 passes through the center of the second rotating body 24 and is cut by a plane perpendicular to the rotation axis of the intermediate rotating body 22 and parallel to the Z-axis direction. FIG. 12 is a cross-sectional view showing the periphery of the third rotating body 38 and the connecting rotating body 33. FIG. 12 shows a vertical cross section of the encoder 160 as viewed from substantially the right side. FIG. 12 shows a state in which the encoder 160 is cut in a plane parallel to the Z-axis direction passing through the center of the third rotating body 38 and the center of the connecting rotating body 33. In FIGS. 11 and 12, the description of the housing 3 and the lid 4 is omitted.

The encoder 160 includes a base 2, a housing 3, a lid 4, a substrate 5, an urging portion 62, and a plurality of fixtures 64. The base 2 is a base that rotatably supports each rotating body and each gear. The columns 2c arranged on the base 2 support the substrate 5. The substrate 5 mainly supports the angle sensors Sp, Sq, Sr and the control unit 40. The base 2 includes a bottom 2b and a plurality of (eg, 4) stanchions 2c. The bottom portion 2b is a plate-shaped portion facing the motor 1 side of the encoder 160, and extends in the X-axis direction and the Y-axis direction. The support column 2c is a substantially columnar portion that protrudes from the bottom portion 2b in the direction away from the motor 1 in the axial direction. A hollow square cylindrical housing 3 is fixed to the bottom 2b of the base 2 by a plurality of (for example, three) fixtures 64. The fixative 64 may be, for example, a screw. The substrate 5 is fixed to the protruding end of the support column 2c by using, for example, a screw (not shown). The urging unit 62 will be described later.

Further, the encoder 160 includes a first rotating body 20, a first worm gear 10, a first worm wheel 12, an intermediate rotating body 22, a second worm gear 14, a second worm wheel 16, and a second rotation. Body 24, third worm gear 30, third worm wheel 32, connecting rotating body 33, driving gear 34, driven gear 36, third rotating body 38, magnets Mp, Mq, Mr, and angles. It includes sensors Sp, Sq, Sr and a control unit 40 (see FIG. 8).

(1st rotating body)
The first rotating body 20 rotates according to the rotation of the spindle 1a, and transmits the rotation of the spindle 1a to the first worm gear 10. The first rotating body 20 includes a connecting portion 20b that fits on the outer periphery of the spindle 1a, a gear forming portion 20c on which the first worm gear 10 is formed, and a holding portion 20d that holds the magnet Mq. The connecting portion 20b has a cylindrical shape surrounding the main shaft 1a. The gear forming portion 20c has a disk shape extending radially from the outer periphery of the connecting portion 20b. The holding portion 20d has a cylindrical concave shape provided on the end face of the gear forming portion 20c far from the bottom portion 2b in the axial direction. The connecting portion 20b, the gear forming portion 20c, and the holding portion 20d are integrally formed so that their central axes substantially coincide with each other. The first rotating body 20 can be formed of various materials such as a resin material and a metal material. In this example, the first rotating body 20 is formed of a polyacetal resin.

(1st worm gear)
The first worm gear 10 is a transmission element that drives the first worm wheel 12. In particular, the first worm gear 10 is a screw gear having a number of threads = 1 formed on the outer periphery of the gear forming portion 20c. The rotation axis of the first worm gear 10 extends in the axial direction of the spindle 1a.

(Intermediate rotating body)
The intermediate rotating body 22 rotates according to the rotation of the main shaft 1a, and transmits the rotation of the main shaft 1a to the second rotating body 24 and the connecting rotating body 33. The intermediate rotating body 22 is rotatably supported around a rotation axis La extending substantially parallel to the bottom portion 2b. The intermediate rotating body 22 is a member having a substantially cylindrical shape extending in the direction of the rotation axis La. The intermediate rotating body 22 is formed with a base portion 22b, a first cylinder portion 22c on which the first worm wheel 12 is formed, a second cylinder portion 22d on which the second worm gear 14 is formed, and a third worm gear 30. The third tubular portion 22e and the supported portions 22f and 22g provided at both ends thereof are included.

The outer wall portion 3b is provided on the side opposite to the main shaft 1a of the intermediate rotating body 22. The outer wall portion 3d is provided on the side where the main shaft 1a of the intermediate rotating body 22 is arranged in parallel with the outer wall portion 3b. The intermediate rotating body 22 may be arranged so that its rotation axis La faces in any direction. The rotation axis La of the intermediate rotating body 22 is provided so as to be inclined in a range of 5 ° to 30 ° with respect to the stretching direction of the outer wall portion 3b provided on the side opposite to the main axis 1a of the intermediate rotating body 22 in a plan view. You may. In the example of FIG. 9, the rotation axis La of the intermediate rotating body 22 is inclined by 20 ° with respect to the stretching direction of the outer wall portion 3b. In other words, the housing 3 includes an outer wall portion 3b extending in a direction inclined in a range of 5 ° to 30 ° with respect to the rotation axis La of the intermediate rotating body 22 in a plan view. In the example of FIG. 9, the inclination Ds between the extending direction of the outer wall portion 3b and the rotation axis La of the intermediate rotating body 22 is set to 20 °.

In this example, the base portion 22b has a cylindrical shape, and the first cylinder portion 22c, the second cylinder portion 22d, and the third cylinder portion 22e have a cylindrical shape having a diameter larger than that of the base portion 22b. The base portion 22b, the first cylinder portion 22c, the second cylinder portion 22d, the third cylinder portion 22e, and the supported portions 22f and 22g are integrally formed so that their central axes substantially coincide with each other. The second cylinder portion 22d, the first cylinder portion 22c, and the third cylinder portion 22e are arranged at positions separated from each other in this order. The intermediate rotating body 22 can be formed of various materials such as a resin material and a metal material. In this example, the intermediate rotating body 22 is formed of a polyacetal resin.

In this example, the supported portions 22f and 22g are supported by the supporting portions 2f and 2g in which a part of the bottom portion 2b is cut up. The support portions 2f and 2g are provided with holes penetrating in the rotation axis direction of the intermediate rotating body 22 and into which the supported portions 22f and 22g are fitted. With this configuration, the intermediate rotating body 22 is rotatably supported by the support portions 2f and 2g.

(Burning department)
The urging unit 62 will be described. In the intermediate rotating body 22, when the second worm gear 14 and the third worm gear 30 drive each worm wheel, a reaction force acts in the rotation axis direction of the intermediate rotating body 22, and the position in the rotation axis direction changes. Sometimes. Therefore, in this example, an urging portion 62 for applying an urging force to the intermediate rotating body 22 is provided. The urging unit 62 applies an urging force in the direction opposite to the reaction force to the intermediate rotating body 22, thereby suppressing the position change in the rotation axis direction. The urging portion 62 includes a mounting portion 62b attached to the bottom portion 2b and a spring portion 62c extending from the mounting portion 62b and coming into contact with the hemispherical protrusion 22h. The mounting portion 62b and the spring portion 62c are formed of a thin plate-shaped spring material, and the root of the spring portion 62c is bent at a substantially right angle to the mounting portion 62b in the middle. By urging the hemispherical protrusion 22h by the urging portion 62 in this way, it is possible to suppress the fluctuation of the position of the intermediate rotating body 22 in the rotation axis direction while reducing the influence on the rotational operation of the intermediate rotating body 22. It will be possible.

In this example, the direction of the reaction force received by the intermediate rotating body 22 due to the rotation of the second worm gear 14 is set to be opposite to the direction of the reaction force received by the intermediate rotating body 22 due to the rotation of the third worm gear. Will be done. In particular, the tooth shape of each worm gear is set so that the components of the intermediate rotating body 22 of each reaction force in the direction of the rotation axis are opposite to each other. Specifically, the inclination direction of the teeth in each worm gear is set so that the directions of the components in the rotation axis direction of the intermediate rotating body 22 of the reaction force are opposite to each other. In this case, since the combined reaction force is smaller than when the reaction force directions of the worm gears are the same, the urging force of the urging portion 62 can be reduced accordingly. In this case, the rotational resistance of the intermediate rotating body 22 is reduced and the intermediate rotating body 22 can rotate smoothly.

(1st worm wheel)
The first worm wheel 12 is a transmission element driven by the first worm gear 10. In particular, the first worm wheel 12 is a spiral gear having 20 teeth formed on the outer periphery of the first cylinder portion 22c. The first worm gear 10 and the first worm wheel 12 constitute the first worm transmission mechanism 11. The rotation axis of the first worm wheel 12 extends in a direction perpendicular to the axial direction of the main shaft 1a.

(2nd worm gear)
The second worm gear 14 is a transmission element that drives the second worm wheel 16. In particular, the second worm gear 14 is a screw gear having a number of threads = 5 formed on the outer periphery of the second cylinder portion 22d. The rotation axis of the second worm gear 14 extends in a direction perpendicular to the axial direction of the spindle 1a.

(2nd rotating body)
The second rotating body 24 rotates according to the rotation of the spindle 1a, decelerates the rotation of the spindle 1a, and transmits the rotation to the magnet Mp. The second rotating body 24 is rotatably supported around a rotation axis extending substantially vertically from the bottom 2b. The second rotating body 24 is a member having a substantially circular shape in a plan view. It includes a bearing portion 24b rotatably supported by the bottom portion 2b, an overhanging portion 24c on which the second worm wheel 16 is formed, and a holding portion 24d for holding the magnet Mp. The bearing portion 24b has a cylindrical shape that surrounds the protruding shaft 24s protruding from the bottom portion 2b with a gap.

The overhanging portion 24c has a disk shape that overhangs in the radial direction from the outer periphery of the bearing portion 24b. In this example, the overhanging portion 24c is provided at a position closer to the end portion farther from the bottom portion 2b of the bearing portion 24b. The holding portion 24d has a cylindrical concave shape provided on the end face of the overhanging portion 24c far from the bottom portion 2b in the axial direction. The bearing portion 24b, the overhanging portion 24c, and the holding portion 24d are integrally formed so that their central axes substantially coincide with each other. The second rotating body 24 can be formed of various materials such as a resin material and a metal material. In this example, the second rotating body 24 is formed of a polyacetal resin.

(2nd worm wheel)
The second worm wheel 16 is a helical gear driven by the second worm gear 14. In particular, the second worm wheel 16 is a helical gear having 25 teeth formed on the outer periphery of the overhanging portion 24c. The second worm gear 14 and the second worm wheel 16 constitute a second worm transmission mechanism 15. The rotation axis of the second worm wheel 16 extends in a direction parallel to the axial direction of the spindle 1a.

The third worm gear 30 is a transmission element that drives the third worm wheel 32. In particular, the third worm gear 30 is a screw gear having a number of threads = 1 formed on the outer periphery of the third tubular portion 22e. The rotation axis of the third worm gear 30 extends in a direction perpendicular to the axial direction of the spindle 1a.

(Connecting rotating body)
The connecting rotating body 33 rotates according to the rotation of the main shaft 1a, decelerates the rotation of the main shaft 1a, and transmits the rotation to the third rotating body 38. The connecting rotating body 33 is rotatably supported around a rotation axis extending substantially vertically from the bottom portion 2b. The connecting rotating body 33 is a member having a substantially circular shape in a plan view. A bearing portion 33b rotatably supported by the bottom portion 2b and an overhanging portion 33c on which the third worm wheel 32 is formed are included. The bearing portion 33b has a cylindrical shape that surrounds the protruding shaft 33s protruding from the bottom portion 2b with a gap.

By providing the connecting rotating body 33, the third rotating body 38, which will be described later, can be arranged at a position away from the third worm gear 30. Therefore, the distance between the magnets Mq and Mr can be lengthened to reduce the influence of the mutual leakage flux. Further, by providing the connecting rotating body 33, the range in which the reduction ratio can be set is expanded by that amount, and the degree of freedom in design is improved.

The overhanging portion 33c has a disk shape that overhangs in the radial direction from the outer periphery of the bearing portion 33b. In this example, the overhanging portion 33c is provided at a position closer to the end portion farther from the bottom portion 2b of the bearing portion 33b. The drive gear 34 is formed on the outer periphery of the region on the bottom 2b side of the overhanging portion 33c of the bearing portion 33b. The bearing portion 33b and the overhanging portion 33c are integrally formed so that their central axes are substantially aligned with each other. The connecting rotating body 33 can be formed of various materials such as a resin material and a metal material. In this example, the connecting rotating body 33 is formed of a polyacetal resin.

(3rd worm wheel)
The third worm wheel 32 is a transmission element driven by the third worm gear 30. In particular, the third worm wheel 32 is a spiral gear having 30 teeth formed on the outer periphery of the overhanging portion 33c. The third worm gear 30 and the third worm wheel 32 constitute a third worm transmission mechanism 31. The rotation axis of the third worm wheel 32 extends in a direction parallel to the axial direction of the spindle 1a.

(Drive gear)
The drive gear 34 is a transmission element that drives the driven gear 36. In particular, the drive gear 34 is a spur gear having 24 teeth formed on the outer periphery of the bearing portion 33b.

(3rd rotating body)
The third rotating body 38 rotates according to the rotation of the spindle 1a, decelerates the rotation of the spindle 1a, and transmits the rotation to the magnet Mr. The third rotating body 38 is rotatably supported around a rotation axis extending substantially vertically from the bottom 2b. The third rotating body 38 is a member having a substantially circular shape in a plan view. The third rotating body 38 includes a bearing portion 38b rotatably supported by the bottom portion 2b, an overhanging portion 38c on which the driven gear 36 is formed, and a holding portion 38d for holding the magnet Mr. The bearing portion 38b has a cylindrical shape that surrounds the shaft 38s protruding from the bottom portion 2b with a gap.

The overhanging portion 38c has a disk shape that overhangs in the radial direction from the outer periphery of the bearing portion 38b. In this example, the overhanging portion 38c is provided at a position closer to the bottom portion 2b of the bearing portion 38b. The holding portion 38d has a cylindrical concave shape provided on the end face of the bearing portion 38b far from the bottom portion 2b in the axial direction. The bearing portion 38b, the overhanging portion 38c, and the holding portion 38d are integrally formed so that their central axes substantially coincide with each other. The third rotating body 38 can be formed of various materials such as a resin material and a metal material. In this example, the third rotating body 38 is formed of a polyacetal resin.

(Driven gear)
The driven gear 36 is a transmission element driven by the drive gear 34. In particular, the driven gear 36 is a spur gear having 60 teeth formed on the outer periphery of the overhanging portion 38c. The drive gear 34 and the driven gear 36 constitute a reduction mechanism 35.

(magnet)
The magnets Mp, Mq, and Mr (hereinafter referred to as each magnet) have a substantially cylindrical shape flat in the axial direction. Each magnet is formed of, for example, a ferrite-based or NdFeB-based magnetic material. Each magnet may be, for example, a rubber magnet containing a resin binder or a bond magnet. Each magnet is provided with a magnetic pole. The magnetization direction of each magnet is not limited, but in this example, the two poles Up, Uq, and Ur are provided on the end faces of the magnets facing the angle sensor. The magnetic flux density distribution in the rotation direction of each magnet may be a trapezoidal wave shape, a sinusoidal wave shape, or a rectangular wave shape. In the embodiment, it is magnetized in a trapezoidal wavy shape.

Each magnet is partially or wholly housed in a recess formed at the end of each rotating body and is fixed, for example, by adhesion or caulking. The magnet Mp is adhesively fixed to the holding portion 24d of the second rotating body 24, the magnet Mq is adhesively fixed to the holding portion 20d of the first rotating body 20, and the magnet Mr is adhered to the holding portion 38d of the third rotating body 38.

If the distance between the magnets is short, the detection error of the angle sensor becomes large due to the influence of the leakage flux of the magnets adjacent to each other. Therefore, in the example of FIG. 9, in the plan view, the magnets are arranged apart from each other on a straight line (hereinafter referred to as an arrangement straight line Lm) inclined with respect to the outer wall portion 3b of the housing 3. The distance between the magnets can be increased as compared with the case where the arrangement straight line Lm is parallel to the outer wall portion 3b. From this point of view, the inclination of the arrangement straight line Lm with respect to the outer wall portion 3b is preferably in the range of 30 ° to 60 ° in the case of the present embodiment, and is set in the range of 38 ° to 42 ° in the example of FIG.

(Angle sensor)
The angle sensors Sp, Sq, and Sr (hereinafter referred to as each angle sensor) are sensors that detect an absolute rotation angle in the range of 0 ° to 360 ° corresponding to one rotation of each rotating body. Each angle sensor outputs a signal (for example, a digital signal) corresponding to the detected angle of rotation to the control unit 40. Each angle sensor outputs the same angle of rotation as before the energization was stopped, even when the energization was once stopped and then re-energized. Therefore, a configuration without a backup power supply is possible.

As shown in FIG. 8, each angle sensor is fixed flush to the surface of the substrate 5 on the bottom 2b side by a method such as soldering or bonding. The angle sensor Sp is fixed to the substrate 5 at a position facing the magnetic pole Up of the magnet Mp provided on the second rotating body 24 via a gap. The angle sensor Sq is fixed to the substrate 5 at a position facing the magnetic pole Uq of the magnet Mq provided on the first rotating body 20 via a gap. The angle sensor Sr is fixed to the substrate 5 at a position facing the magnetic pole Ur of the magnet Mr provided on the third rotating body 38 via a gap.

A magnetic angle sensor having a relatively high resolution may be used for each angle sensor. The magnetic angle sensor is arranged so as to face each other through a gap with the magnetic poles of each magnet in the axial direction of each rotating body, identifies the rotation angle of the rotor based on the rotation of these magnetic poles, and outputs a digital signal. As an example, the magnetic angle sensor includes 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 of (for example, four) magnetic field detection elements such as a Hall element and a GMR (Giant Magneto Resistive) element.

In the arithmetic circuit, for example, the rotation angle may be specified by table processing using a look-up table using the difference or ratio of the outputs of a plurality of detection elements as a key. The detection element and the arithmetic circuit may be integrated on one IC chip. This IC chip may be embedded in a resin having a thin rectangular parallelepiped outer shape. Each angle sensor outputs an angle signal, which is a digital signal corresponding to the rotation angle of each rotor detected via a wiring member (not shown), to the control unit 40. For example, each angle sensor outputs the rotation angle of each rotating body as a digital signal of a plurality of bits (for example, 7 bits).

(Control unit)
The control unit 40 will be described. Each block of the control unit 40 shown in FIG. 4 can be realized by an element such as a CPU (central processing unit) of a computer or a mechanical device in terms of hardware, and can be realized by a computer program or the like in terms of software. However, here, the functional blocks realized by their cooperation are drawn. Therefore, it is understood by those skilled in the art who have touched this specification that these functional blocks can be realized in various forms by combining hardware and software.

The control unit 40 includes rotation angle acquisition units 40p, 40q, 40r, a correspondence table 40b, a rotation amount specifying unit 40c, and an output unit 40e. The rotation angle acquisition unit 40p acquires the rotation angle Ap of the second rotating body 24 detected by the angle sensor Sp. The rotation angle acquisition unit 40q acquires the rotation angle Aq of the first rotating body 20 detected by the angle sensor Sq. The rotation angle acquisition unit 40r acquires the rotation angle Ar of the third rotating body 38 detected by the angle sensor Sr. The correspondence table 40b specifies the rotation speed of the spindle 1a corresponding to the acquired rotation angles Ap and Ar by the table processing. The rotation amount specifying unit 40c specifies the rotation amount of the spindle 1a over a plurality of rotations according to the rotation number of the spindle 1a specified by the correspondence table 40b and the acquired rotation angle Aq. The output unit 40e converts the amount of rotation of the specified spindle 1a over a plurality of rotations into a signal of a desired format and outputs the signal. In this example, as shown in FIG. 8, the control unit 40 is fixed to the surface of the substrate 5 on the bottom 2b side by a method such as soldering or bonding.

The operation / effect of the encoder 160 according to the fourth embodiment configured in this way will be described.

The encoder 160 according to the fourth embodiment is an absolute encoder that specifies the amount of rotation over a plurality of rotations of the spindle 1a, and meshes with the first worm gear 10 that rotates according to the rotation of the spindle 1a and the first worm gear 10. A matching first worm wheel 12, a second worm gear 14 that rotates according to the rotation of the first worm wheel 12, a second worm wheel 16 that meshes with the second worm gear 14, and a second worm wheel 16 that rotates according to the rotation. It is provided with an angle sensor Sp that detects the rotation angle of the second rotating body 24. According to this configuration, it is possible to specify the amount of rotation over a plurality of rotations of the spindle 1a according to the detection result of the angle sensor Sp. An encoder to provide a first worm transmission mechanism 11 including a first worm gear 10 and a first worm wheel 12, and a second worm transmission mechanism 15 including a second worm wheel 16 that meshes with the second worm gear 14. The 160 can be made thinner by forming a bent transmission path. This action / effect can also be exerted on the encoders 100, 120, 140 according to the first to third embodiments having the same configuration.

The encoder 160 according to the fourth embodiment is an absolute encoder that specifies the amount of rotation over a plurality of rotations of the spindle 1a, and is an intermediate rotating body 22 that rotates at a first reduction ratio with the rotation of the spindle 1a, and an intermediate rotation. A second rotating body 24 that rotates at a second reduction ratio with the rotation of the body 22 and an angle sensor Sp that detects the rotation angle of the second rotating body 24 are provided, and the rotation axis of the main shaft 1a is the intermediate rotating body 22. It is in a twisted position with respect to the rotation axis of the second rotating body 24, and is set parallel to the rotation axis of the second rotating body 24. According to this configuration, it is possible to specify the amount of rotation over a plurality of rotations of the spindle 1a according to the detection result of the angle sensor Sp. Since the rotation axis of the intermediate rotating body 22 is in a twisted position with respect to the rotation axes of the main shaft 1a and the second rotating body 24 and is orthogonal to each other in front view, the encoder 160 should be made thinner by forming a bent transmission path. Can be done. This action / effect can also be exerted on the encoders 100, 120, 140 according to the first to third embodiments having the same configuration.

The encoder 160 according to the fourth embodiment is an absolute encoder that specifies the amount of rotation over a plurality of rotations of the spindle 1a, includes the first worm transmission mechanism 11, and decelerates the magnet Mp to rotate with the rotation of the spindle 1a. It includes a mechanism and an angle sensor Sp that detects the rotation angle of the magnet Mp according to the magnetic pole Up of the magnet Mp, and the rotation axis of the spindle 1a is set parallel to the rotation axis of the magnet Mp. According to this configuration, it is possible to specify the amount of rotation over a plurality of rotations of the spindle 1a according to the detection result of the angle sensor Sp. Since the first worm transmission mechanism 11 is included and the rotation axis of the spindle 1a and the rotation axis of the magnet Mp are set in parallel, the encoder 160 can be made thinner by forming a bent transmission path. This action / effect can also be exerted on the encoders 100, 120, 140 according to the first to third embodiments having the same configuration.

The encoder 160 according to the fourth embodiment includes an angle sensor Sq that detects the rotation angle of the spindle 1a. According to this configuration, the rotation angle of the spindle 1a can be specified according to the detection result of the angle sensor Sq. The encoder 160 can improve the resolution of the angle of rotation of the identifiable spindle 1a as compared with the case where the angle sensor Sq is not provided. This action / effect can also be exerted on the encoder 120 according to the second embodiment having the same configuration.

In the encoder 160 according to the fourth embodiment, the third worm gear 30 that rotates according to the rotation of the first worm wheel 12, the third worm wheel 32 that meshes with the third worm gear 30, and the third worm wheel 32 rotate. It is provided with an angle sensor Sr that detects the rotation angle of the rotating third rotating body 38. According to this configuration, it is possible to specify the amount of rotation over a plurality of rotations of the spindle 1a according to the detection result of the angle sensor Sq. The encoder 160 can increase the range of the amount of rotation of the identifiable spindle 1a as compared with the case where the angle sensor Sr is not provided. This action / effect can also be exerted on the encoder 140 according to the third embodiment having the same configuration.

The encoder 160 according to the fourth embodiment includes an intermediate rotating body 22 provided with the second worm gear 14 and the third worm gear 30, and the reaction force received by the intermediate rotating body 22 due to the rotation of the second worm gear 14 The direction is set to be opposite to the direction of the reaction force received by the intermediate rotating body 22 due to the rotation of the third worm gear. According to this configuration, the combined reaction force of both reaction forces can be reduced as compared with the case where the directions of the reaction forces are the same. This action / effect can also be exerted on the encoder 140 according to the third embodiment having the same configuration.

In the encoder 160 according to the fourth embodiment, the outer diameter of the first worm wheel 12 is set to be smaller than the outer diameter of the first worm gear 10. According to this configuration, it is easier to reduce the thickness as compared with the case where the outer diameter of the first worm wheel 12 is large. This action / effect can also be exerted on the encoders 100, 120, 140 according to the first to third embodiments having the same configuration.

The encoder 160 according to the fourth embodiment includes a housing 3 including an outer wall portion 3b arranged on the side opposite to the main shaft 1a of the intermediate rotating body 22, and in a plan view, the rotating axis La of the intermediate rotating body 22 is an outer wall. It is inclined at 20 ° with respect to the extending direction of the portion 3b. According to this configuration, the inclination of the arrangement straight line of each magnet with respect to the outer wall portion 3b can be increased as compared with the case where the rotation axis La of the intermediate rotating body 22 is not inclined. As a result, the distance between the magnets becomes large, and the influence of the leakage flux of the adjacent magnets can be reduced. This action / effect can also be exerted on the encoders 100, 120, 140 according to the first to third embodiments having the same configuration.

[Fifth Embodiment]
The encoder 200 according to the fifth embodiment of the present invention will be described with reference to FIGS. 13 and 14. FIG. 13 is a plan view of the encoder 200 according to the fifth embodiment. FIG. 13 corresponds to FIG. FIG. 14 is a front view of the encoder 200. FIG. 14 corresponds to FIG. The encoder 200 does not have the angle sensor Sq and the magnet Mq with respect to the encoder 160 according to the fourth embodiment, and the shapes of the spindle 201a, the first rotating body 220, the substrate 205, and the lid 204 are different, and the like. The configuration of is similar. The description that overlaps with the fourth embodiment will be omitted, and the different configurations will be described. The spindle 201a, the first rotating body 220, the substrate 205, and the lid portion 204 correspond to the spindle 1a, the first rotating body 20, the substrate 5, and the lid portion 4, respectively, and have the same characteristics. The spindle 201a penetrates the opening 220h provided in the first rotating body 220, the opening 205h provided in the substrate 205, and the opening 204h provided in the lid portion 204, and projects axially away from the motor 1. ing. In the present specification, an encoder 200 having a spindle protruding to both sides of the motor 1 is referred to as a double shaft, and an encoder 160 having a spindle protruding to only one side of the motor 1 is referred to as a single shaft. The spindle 201a is a solid shaft having a narrow cross section.

The encoder 200 according to the fifth embodiment exhibits the same action / effect in a portion having the same configuration as the encoder 160 according to the fourth embodiment. In the encoder 200 according to the fifth embodiment, since the spindle 201a, which is the output shaft of the motor 1, has a protruding portion protruding from the side opposite to the motor 1 of the encoder 200, a driven load is connected to the protruding portion. can do. It is possible to realize a so-called biaxial configuration in which the spindle 201a protrudes to the side opposite to the encoder 200 of the motor 1. Therefore, the encoder 200 can be used for various purposes.

[Sixth Embodiment]
The encoder 300 according to the sixth embodiment of the present invention will be described with reference to FIGS. 15 and 16. FIG. 15 is a plan view of the encoder 300 according to the sixth embodiment. FIG. 15 corresponds to FIG. FIG. 16 is a front view of the encoder 300. FIG. 16 corresponds to FIG. The encoder 300 differs from the encoder 200 according to the fifth embodiment in the shapes of the spindle 301a, the first rotating body 320, the substrate 305, and the lid 304, and has the same other configurations. The description that overlaps with the fifth embodiment will be omitted, and the different configurations will be described. The spindle 301a, the first rotating body 320, the substrate 305, and the lid portion 304 correspond to the spindle 201a, the first rotating body 220, the substrate 205, and the lid portion 204, respectively, and have the same characteristics. While the main shaft 201a is a solid shaft, the main shaft 301a is a hollow shaft and has a diameter larger than that of the main shaft 201a. The spindle 301a penetrates the opening 320h provided in the first rotating body 320, the opening 305h provided in the substrate 305, and the opening 304h provided in the lid 304. The opening 320h, the opening 305h, and the opening 304h are enlarged from the opening 220h, the opening 205h, and the opening 204h, respectively, in accordance with the increase in the diameter of the spindle 301a.

The encoder 300 according to the sixth embodiment has the same operation and effect as the encoder 200 according to the fifth embodiment. Since the main shaft 301a, which is the output shaft of the motor 1, is hollow in the encoder 300 according to the sixth embodiment, a driven load can be connected to the hollow portion.

[7th Embodiment]
The encoder 400 according to the seventh embodiment of the present invention will be described with reference to FIGS. 17 and 18. FIG. 17 is a plan view of the encoder 400 according to the seventh embodiment. FIG. 17 corresponds to FIG. FIG. 18 is a front view of the encoder 400. FIG. 18 corresponds to FIG. The encoder 400 has a different shape of the spindle 401a and the first rotating body 420 from the encoder 160 according to the fourth embodiment, and has the same other configurations. The description that overlaps with the fourth embodiment will be omitted, and the different configurations will be described.

The spindle 401a and the first rotating body 420 correspond to the spindle 1a and the first rotating body 20, respectively, and have similar characteristics. Whereas the main shaft 1a was a solid shaft, the main shaft 401a is a hollow shaft and has a diameter larger than that of the main shaft 1a. In the first rotating body 320, the inner diameter of the portion surrounding the main shaft 401a is increased in response to the increase in the outer diameter of the main shaft 401a. The first rotating body 320 has a portion that covers the end face of the hollow spindle 401a.

The encoder 400 according to the seventh embodiment has the same operation and effect as the encoder 160 according to the fourth embodiment. Since the main shaft 401a, which is the output shaft of the motor 1, is hollow in the encoder 400 according to the seventh embodiment, a driven load can be connected to the hollow portion.

[Eighth Embodiment]
The encoder 500 according to the eighth embodiment of the present invention will be described with reference to FIG. FIG. 19 is a plan view of the encoder 500 according to the eighth embodiment. In FIG. 19, insignificant members and parts are omitted for ease of understanding. The encoder 500 is provided with the rotation axis Lb of the intermediate rotating body 22 parallel to the extending direction (X-axis direction) of the outer wall portion 3b with respect to the encoder 160 according to the fourth embodiment. The other configurations are the same except that the inclination of the outer wall portion 3b of the Ln with respect to the extending direction is set to be small. The description that overlaps with the fourth embodiment will be omitted, and the different configurations will be described. In the example of FIG. 19, the inclination of the outer wall portion 3b of the arrangement straight line Ln of each magnet with respect to the stretching direction is set to 20 °.

The encoder 500 according to the eighth embodiment exhibits the same action / effect in a portion having the same configuration as the encoder 160 according to the fourth embodiment. In the encoder 500 according to the eighth embodiment, the intermediate rotating body 22 can be configured to be short, and the weight can be reduced by that amount.

FIG. 20 is a specification classification table of the encoder according to each embodiment. As shown in FIG. 20, the encoder of each embodiment can be developed into various specifications. In particular, by making the basic configuration common and selecting the shape of the first rotating body, it is possible to correspond to the specifications of any combination of the hollow and solid spindles and the single shaft and both shafts. Further, by selecting the presence or absence of the angle sensor Sq, it is possible to correspond to both high resolution and medium resolution specifications for the rotation angle of the spindle. Further, by selecting the presence / absence of the angle sensor Sr, it is possible to correspond to both a wide range and a medium range of the range of the amount of rotation of the main shaft that can be detected. In other words, by standardizing the platform and improving the sharing rate of components, design efficiency can be improved and production costs can be reduced, making it easier to meet diverse needs.

The above description has been made based on each embodiment of the present invention. It will be appreciated by those skilled in the art that these embodiments are exemplary and that various modifications and modifications are possible within the claims of the invention, and that such modifications and modifications are also within the claims of the present invention. It is about to be done. Therefore, the descriptions and drawings herein should be treated as exemplary rather than limiting.

Hereinafter, a modified example will be described. In the drawings and description of the modified examples, the same or equivalent components and members as in each embodiment are designated by the same reference numerals. The description that overlaps with each embodiment will be omitted as appropriate, and the configuration different from the embodiment will be mainly described.

(First modification)
In the description of each embodiment, an example in which each magnet is an integral member has been described, but the present invention is not limited to this. The magnets Mp, Mq, and Mr may each be configured by combining a plurality of pieces.

(Second modification)
In the description of each embodiment, an example in which each gear and each rotating body is formed of a resin material has been described, but the present invention is not limited to this. All or part of each of these gears and each rotating body may be formed of a metal material or other material.

According to the above-mentioned modification, the same action / effect is obtained in the portion having the same configuration as each embodiment.

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

1 ... motor, 1a ... spindle, 2 ... base, 3 ... housing, 10 ... 1st worm gear, 12 ... 1st worm wheel, 14 ... 2nd worm gear, 16 ... 2nd Worm wheel, 20 ... 1st rotating body, 22 ... Intermediate rotating body, 24 ... 2nd rotating body, 30 ... 3rd worm gear, 32 ... 3rd worm wheel, 38 ... 3rd rotating body, 40 ... Control unit, 100, 120, 140, 160 ... Encoder.

Claims (8)

An absolute encoder that specifies the amount of rotation over multiple rotations of the spindle.
The first drive gear that rotates according to the rotation of the spindle,
The first driven gear that meshes with the first drive gear,
A second drive gear that rotates according to the rotation of the first driven gear,
A second driven gear that meshes with the second drive gear,
An angle sensor that detects the angle of rotation of the second rotating body that rotates according to the rotation of the second driven gear, and
A bottom, a plurality of columns protruding from the bottom, a base having,
A substrate that is arranged to face the bottom and is fixed to the plurality of columns.
Equipped with
The first drive gear, the first driven gear, the second drive gear, and the second driven gear are arranged on the surface of the bottom portion on the substrate side.
The angle sensor is arranged on the bottom surface of the substrate.
The first drive gear is a worm gear and is a worm gear.
The first driven gear is a worm wheel.
The second drive gear is a worm gear and is a worm gear.
The second driven gear is an absolute encoder characterized by being a worm wheel. The absolute encoder according to claim 1, wherein the plurality of columns include two columns arranged apart from each other with the first driven gear interposed therebetween. The base has an outer wall portion extending from the bottom portion.
The absolute encoder according to claim 1 or 2, wherein the substrate is surrounded by the outer wall portion through a gap. The first drive gear, the first driven gear, the second drive gear, and the second driven gear constitute a rotation transmission path for transmitting the rotation of the spindle.
The rotation transmission path is arranged so as to be bent along the bottom portion .
The absolute encoder according to any one of claims 1 to 3, wherein the second driven gear is a terminal of the rotation transmission path . Further equipped with another angle sensor for detecting the rotation angle of the spindle,
The other aspect of the present invention is characterized in that the other angle sensor is provided on the side opposite to the bottom portion with the first drive gear, the first driven gear, the second drive gear, and the second driven gear interposed therebetween. The absolute encoder according to any one of 1 to 4 . The absolute encoder according to any one of claims 1 to 5, wherein the outer diameter of the first driven gear is set to be smaller than the outer diameter of the first drive gear. The absolute encoder according to any one of claims 1 to 6, wherein the absolute encoder has a rectangular parallelepiped shape that is flat in a direction along the rotation axis of the main shaft. The outer wall portion includes a specific outer wall portion arranged on the side opposite to the main shaft of the first driven gear.
The absolute encoder according to claim 3 , wherein the rotary axis of the first driven gear is inclined in a range of 5 ° to 30 ° with respect to the extending direction of the specific outer wall portion in a plan view. ..

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