JP6794654B2 - Encoder device, drive device, stage device, and robot device - Google Patents

Description

The present invention relates to an encoder device, a drive device, a stage device, and a robot device.

An encoder device that detects rotation information (sometimes referred to as rotation position information) is mounted on various devices such as a drive device (for example, a motor device) (see, for example, Patent Document 1 below). The encoder device includes, for example, a rotating unit provided on the rotating shaft of the driving device and rotates, and the detection unit detects light or magnetism from the pattern of the rotating unit to acquire rotation information.

Japanese Unexamined Patent Publication No. 2004-318439

It is desired that the encoder device can acquire rotation information with high accuracy. In the encoder device, for example, when the position of the rotating shaft fluctuates, the positional deviation between the rotating portion (pattern) and the detecting portion occurs. Due to the misalignment between the two, the accuracy of the acquired rotation information may decrease.

According to the first aspect of the present invention, a rotating portion fixed to a rotating shaft to be measured and having a pattern formed, a detecting portion for detecting the pattern, and a substrate to which the detecting portion is attached and allowing rotation of the rotating portion are attached. And an encoder device including a support portion having a connection portion for connecting between a case accommodating the rotating portion and the substrate and causing the substrate to follow the movement of the rotating shaft. Further, at least of the rotating portion fixed to the rotating shaft to be measured and the pattern formed, the eccentric movement of the rotating shaft, the movement in the tilting direction with respect to the axial direction, and the movement in the axial direction by detecting the pattern An encoder device including a detection unit that moves in response to one movement and a support unit that supports the detection unit is provided.

According to the second aspect of the present invention, there is provided a drive device including an encoder device according to the first aspect and a drive unit that supplies a driving force to the rotating shaft.

According to the third aspect of the present invention, there is provided a stage device including a moving body and a driving device according to the second aspect of moving the moving body.

According to the fourth aspect of the present invention, a robot device including a driving device according to the second aspect is provided.

It is a figure which shows an example of the encoder device which concerns on 1st Embodiment, (a) is a sectional view, (b) is a plan view, (c) is a part of a side view. It is a figure which shows the state which eccentricity moved of the rotation axis. It is a figure which shows an example of the encoder device which concerns on 2nd Embodiment, (a) is a sectional view, (b) is a plan view, (c) is a part of a side view. It is a figure which shows an example of the encoder device which concerns on 3rd Embodiment, (a) is a sectional view, (b) is a plan view. It is a figure which shows an example of the encoder device which concerns on 4th Embodiment, (a) is a sectional view, (b) is a plan view. It is a figure which shows an example of the encoder device which concerns on 5th Embodiment, (a) is a sectional view, (b) is a plan view. It is sectional drawing which shows an example of the encoder device which concerns on 6th Embodiment. (A) and (B) are cross-sectional views showing a state in which the rotation axis is moved in the sixth embodiment. It is a figure which shows an example of the encoder device which concerns on 7th Embodiment, (a) is a sectional view, (b) is a plan view. It is a figure which shows an example of a drive device. It is a figure which shows an example of a stage apparatus. It is a perspective view which shows an example of a robot apparatus.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention is not limited to this. In addition, in the drawings, the scale may be changed as appropriate, such as drawing a part larger or emphasized. In addition, the directions will be described using the XYZ coordinate systems shown in the following figures as appropriate. In each of the X direction, the Y direction, and the Z direction, it is assumed that the direction of the arrow in the drawing is the + direction (eg, the + X direction) and the opposite direction is the − direction (eg, the −X direction).

[First Embodiment]
FIG. 1 is a diagram showing an example of the encoder device 100 according to the first embodiment. FIG. 1A is a cross-sectional view taken along a plane parallel to the XZ plane, and FIG. 1B is a plan view when viewed in the −Z direction. FIG. 1C will be described later. As shown in FIGS. 1A and 1B, the encoder device 100 includes a rotating unit 10, a detecting unit 20, a case unit 30, and a supporting unit 40. The encoder device 100 is attached to, for example, a drive unit 101 such as a motor. The encoder device 100 detects rotation information (rotation position information) of the rotation shaft 102 of the drive unit 101. The rotary shaft 102 is, for example, a shaft (rotor) of a motor, but may be an action shaft (output shaft) connected to a load. The working shaft is connected to the shaft of the motor, for example, via a power transmission unit such as a transmission. The rotation information detected by the encoder device 100 is supplied to, for example, the control unit of the drive unit 101. This control unit controls the rotation of the rotation shaft 102 by using the rotation information supplied from the encoder device 100.

The rotation information includes multi-rotation information indicating the number of rotations of the rotation shaft 102 and angular position information indicating an angular position (rotation angle) of the rotation shaft 102 less than one rotation. The multi-rotation information may be information in which the number of rotations is expressed as an integer, for example, 1 rotation or 2 rotations, or the number of rotations is an angle (eg, an integral multiple of 360 °) such as 360 ° or 720 °. The information represented by may be used. The angular position information is information such as 90 °, 120 °, and 270 °, and the rotation information is a rotation angle of less than one rotation and a rotation angle of one rotation or more, for example, one rotation and 90 ° (450 °). It is information that can be distinguished from. At least one of the rotation information, the multi-rotation information, and the angular position information may be represented by a dimension (eg, radian) other than the degree (°), and the numerical value may be a binary number or the like (eg, a predetermined value). It may be represented by digital data of the number of bits).

The rotating unit 10 has a scale 11. The scale 11 is fixed to the counterload side of the rotating shaft 102 of the drive unit 101 of, for example, a motor or the like. The counterload side is the side of the rotating shaft 102 opposite to the side to which the rotating object driven by the rotating shaft 102 of the driving unit 101 is connected. When the scale 11 is arranged on the opposite side of the load, dirt (eg, oil) from a load or the like with a rotating object is prevented from scattering and adhering to the scale 11.

The scale 11 is, for example, a disk-shaped member, and a plate-shaped scale whose upper surface on the + Z side and lower surface on the −Z side are parallel to the XY plane is used. The scale 11 is fixed to the rotation axis 102 and is arranged perpendicularly (parallel to the XY plane) or substantially perpendicular to the rotation axis 102. Further, the center of the scale 11 is arranged so as to pass through the central axis AX of the rotation of the rotating shaft 102. The material of the scale 11 is arbitrary, and is formed of, for example, metal, resin, or the like.

The scale 11 includes a pattern 12. The pattern 12 is provided on the upper surface of the scale 11 in an annular shape (ring shape). The center of the pattern 12 substantially coincides with the center of the scale 11, for example. Pattern 12 includes at least one of an incremental pattern and an absolute pattern formed concentrically. The pattern 12 is, for example, a light reflection pattern, but is not limited to this, and may be a light transmission pattern.

The detection unit 20 is arranged so as to face the surface of the scale 11 on which the pattern 12 is formed. The detection unit 20 includes a light irradiation unit that irradiates the pattern 12 with light, and a light receiving unit that detects the light that is irradiated and reflected by the pattern 12. The light irradiation unit includes a solid-state light source such as a light emitting diode (LED). The light irradiation unit may include a solid-state light source (eg, a laser diode) other than the light emitting diode, or may include a lamp light source. As the light receiving unit, for example, a photoelectric element or the like is used. The light read by the light receiving unit is transmitted as an electric signal by wire or wirelessly to, for example, a control device (not shown).

The case portion 30 accommodates the rotating portion 10 and the detecting portion 20. The case portion 30 is attached to the main body portion 103 of the drive units 101. The case portion 30 has a cylindrical portion 31 and a lid portion 32. The cylindrical portion 31 is fixed to the + Z side surface of the main body portion 103 by a fixing member (not shown) such as a bolt. The cylindrical portion 31 is arranged so as to surround the rotating portion 10. The cylindrical portion 31 is arranged so that the central axis coincides with the central axis AX of the rotating shaft 102. The lid portion 32 is arranged on the + Z side end face of the cylindrical portion 31. The lid portion 32 is fixed to the cylindrical portion 31 by, for example, a fixing member (not shown), but may be integrally formed with the cylindrical portion 31. The lid portion 32 is arranged so as to face the scale 11 of the rotating portion 10.

The support portion 40 has a substrate 41 and a connection portion 42. The substrate 41 has, for example, a rectangular plate shape, and is arranged at a predetermined interval in the axial direction of the central axis AX with respect to the scale 11. The substrate 41 is arranged parallel to or substantially parallel to the scale 11. Further, the substrate 41 is arranged parallel to or substantially parallel to the lid portion 32.

The detection unit 20 is attached to the −Z side surface of the substrate 41. The substrate 41 may have a circuit that is electrically connected to the detection unit 20. The substrate 41 has a penetrating portion 41a penetrating in the axial direction of the central axis AX. The rotating shaft 102 is passed through the penetrating portion 41a via the bearing 43. The substrate 41 is rotatably supported by the bearing 43 in the direction around the axis of the central axis AX of the rotating shaft 102. With this bearing 43, the substrate is supported by the rotating shaft 102 without rotating the substrate 41 even when the rotating shaft 102 rotates. Further, the substrate 41 is supported by the bearing 43 to maintain a constant distance from the scale 11. As a result, the detection unit 20 can maintain a constant distance from the pattern 12.

The connection portion 42 has a substrate-side hub 44, a case-side hub 45, and a slider 46. The substrate-side hub 44, the case-side hub 45, and the slider 46 form the Oldham coupling 47. FIG. 1C is a diagram showing an example when the connecting portion 42 is viewed in the −X direction. As shown in FIGS. 1A and 1C, the substrate-side hub 44 is fixed to the upper surface of the substrate 41 on the + Z side. The substrate-side hub 44 includes, for example, a convex portion extending in the Y direction. The case-side hub 45 is fixed to the −Z-side surface of the lid portion 32. The case-side hub 45 includes, for example, a convex portion extending in the X direction.

The slider 46 is arranged between the substrate side hub 44 and the case side hub 45 in the Z direction. The slider 46 has a substrate-side recess 46a on the −Z-side surface. The substrate-side recess 46a is formed in a groove shape along the Y direction. The convex portion of the substrate-side hub 44 is fitted into the substrate-side concave portion 46a. The slider 46 can move relative to the substrate-side hub 44 in the Y direction with the convex portion of the substrate-side hub 44 fitted in the substrate-side recess 46a, and the slider 46 can move relative to the substrate-side hub 44. Relative movement in the X direction is regulated.

The slider 46 has a case-side recess 46b on the + Z-side surface. The case-side recess 46b is formed in a groove shape along the X direction. The convex portion of the case-side hub 45 is fitted into the case-side concave portion 46b. The slider 46 can move relative to the case-side hub 45 in the X direction with the convex portion of the case-side hub 45 fitted in the case-side recess 46b, and also with respect to the case-side hub 45. Relative movement in the Y direction is regulated.

In this way, since the slider 46 is connected to the substrate-side hub 44 and the case-side hub 45, respectively, the substrate 41 can move in the X direction or the Y direction. For example, the central axis AX is used as an axis. Movement in the direction of rotation is restricted. On the other hand, since the substrate 41 is supported by the rotating shaft 102 by the bearing 43, when the rotating shaft 102 moves, it moves with the movement of the rotating shaft 102. Therefore, the substrate 41 moves according to the movement of the rotating shaft 102 while being subject to certain restrictions from the Oldham coupling 47. Like the substrate 41, the detection unit 20 fixed to the substrate 41 also moves according to the movement of the rotating shaft 102 while being regulated by the Oldham coupling 47.

When the rotating shaft 102 moves eccentrically, the substrate 41 moves along the XY plane as the rotating shaft 102 moves. The eccentric movement of the rotation axis 102 means that the rotation axis 102 moves in a direction along a plane orthogonal to the central axis AX. For example, when the substrate 41 moves in the X direction together with the rotation shaft 102, the substrate side hub 44 and the slider 46 move in the X direction with respect to the case side hub 45. Further, for example, when the substrate 41 moves in the Y direction integrally with the rotation shaft 102, the substrate side hub 44 moves in the Y direction with respect to the slider 46 (and the case side hub 45). In this way, when the rotation shaft 102 moves eccentrically, the connection unit 42 allows the detection unit 20 to move in the X and Y directions, and restricts the detection unit 20 from rotating around the central axis AX. In addition, the detection unit 20 is supported.

Therefore, when the rotating shaft 102 moves eccentrically, the detection unit 20 moves together with the substrate 41 in the X direction and the Y direction together with the rotating shaft 102. When the rotating shaft 102 moves eccentrically, the rotating portion 10 moves together with the rotating shaft 102 in the same direction as the rotating shaft 102. As a result, when the rotation shaft 102 moves eccentrically, the detection unit 20 moves in the X direction and the Y direction following the rotation unit 10. In this way, the support unit 40 aligns the detection unit 20 with the pattern 12 of the rotation unit 10 by moving following the movement of the rotation shaft 102.

Next, in the encoder device 100 according to the present embodiment, the principle of reducing the detection error due to the eccentricity of the rotating shaft 102 will be described. FIG. 2 is a diagram illustrating a principle that a detection error occurs due to eccentricity. First, FIG. 2A shows a case where the detection unit 20 does not follow the eccentric movement of the rotation shaft 102. As shown in FIG. 2A, for example, in the rotation axis 102, the central axis AX is arranged at the position J1 (r, 0) on the XY coordinate plane, and the central axis AX has the origin (0,0) during rotation. It shall move eccentrically so as to draw a circle at the center. In this case, it is assumed that the detection unit 20 detects the reflected light from the pattern 12a arranged at the position P1 overlapping the X-axis of the pattern 12, for example.

From this state, when the rotation axis 102 rotates counterclockwise by an angle θ in the drawing, the central axis AX eccentrically moves to the position J2 (rcosθ, rsinθ). If the rotation axis 102 rotates while the central axis AX is located at J1, the pattern 12b at the position Q1 which is at an angle θ away from the position P1 moves counterclockwise and is arranged at the position P1. Will be done. In this case, the detection unit 20 detects the reflected light from the pattern 12b arranged at the position P1.

However, when the central axis AX of the rotation axis 102 moves from the position J1 to the position J2 due to the eccentricity, the pattern 12b is arranged at the position Q2 deviated from the X axis to the + Y side. At this time, since the detection unit 20 is still arranged on the X-axis, the pattern 12c is arranged at the position Q3 of the pattern 12 that overlaps the X-axis. Therefore, the detection unit 20 detects the reflected light from the pattern 12c. The position Q3 of the pattern 12c is a position shifted clockwise by an angle β with respect to the position Q2 of the pattern 12b with respect to the central axis AX. Therefore, in the detection unit 20, a detection error corresponding to the angle β occurs.

Here, the coordinates of the position Q3 are calculated assuming that the radius from the central axis AX to the pattern 12a is R.
(Rcosθ + Rcos (-β), rsinθ + Rsin (-β))
Is.

Since the position Q3 is a position that overlaps the X axis, the Y coordinate is 0. Therefore,
rsinθ + Rsin (−β) = 0, from which the angle β is
β = sin ^-1 ((rsin θ) / R).

On the other hand, in the encoder device 100 according to the first embodiment, when the rotation shaft 102 moves eccentrically, the detection unit 20 moves in the X direction and the Y direction together with the rotation unit 10 and the rotation shaft 102. Therefore, as shown in FIG. 2B, when the central axis AX of the rotating shaft 102 moves from the position J1 to the position J2 due to eccentricity, the detection unit 20 follows the moving direction of the central axis AX. Moving. As a result, the relative position between the detection unit 20 and the pattern 12 is suppressed from changing. In this case, the detection unit 20 moves from the X-axis and detects the reflected light from the pattern 12b arranged at the position Q2.

As described above, the encoder device 100 according to the first embodiment can accurately acquire the rotation information of the rotation shaft 102 (rotation unit 10). The encoder device 100 can move together with the rotating portion 10 and the rotating shaft 102 in the direction (X direction, Y direction) in which the detecting unit 20 intersects the central axis AX of the rotating shaft 102. Therefore, even when the rotating shaft 102 moves eccentrically, it is possible to prevent the relative positional relationship between the pattern 12 of the rotating portion 10 and the detecting portion 20 from shifting, and the rotation of the rotating shaft 102 (rotating portion 10). Information can be obtained without error.

In the present embodiment, the Oldham coupling 47 is not limited to the above configuration. For example, any configuration can be applied that allows the substrate 41 to move in the X and Y directions while restricting rotation around the central axis AX. Further, in the Oldham coupling 47, the slider 46 is not limited to being movable in the X direction and the Y direction with respect to the substrate side hub 44 and the case side hub 45, respectively, and can be moved in two directions orthogonal to each other in the XY plane. It is applicable if it is set to. Further, the substrate 41 is not limited to the use of a rectangular plate-shaped member, and for example, a disk-shaped substrate 41 may be used.

[Second Embodiment]
FIG. 3 is a diagram showing an example of the encoder device 200 according to the second embodiment. FIG. 2A is a cross-sectional view taken along a plane parallel to the XZ plane, and FIG. 2B is a plan view when viewed in the −Z direction. As shown in FIGS. 2A and 2B, the encoder device 200 includes a rotating unit 10, a detecting unit 20, a case unit 30, and a supporting unit 140. In the second embodiment, the configuration of the support portion 140 is different from that of the first embodiment, and the other configurations are the same as those of the first embodiment. In the following description, the same or equivalent components as those in the above-described embodiment are designated by the same reference numerals, and the description will be omitted or simplified.

The support portion 140 has a substrate 41 and a connection portion 142. The configuration of the substrate 41 is the same as that of the first embodiment. The connecting portion 142 has a substrate-side parallel spring 144, a case-side parallel spring 145, and a spring support portion 146. The substrate-side parallel spring 144 is attached to the + Z-side surface of the substrate 41. The substrate-side parallel spring 144 is arranged so as to extend in the Y direction. The substrate-side parallel spring 144 has high rigidity in the Y direction, does not elastically deform in the Y direction, or hardly elastically deforms in the Y direction, and is elastically deformable in the X direction.

The case-side parallel spring 145 is attached to the −Z-side surface of the lid portion 32. The case-side parallel spring 145 is arranged so as to extend in the X direction. The case-side parallel spring 145 has high rigidity in the X direction, does not elastically deform in the X direction, or hardly elastically deforms in the X direction, and is elastically deformable in the Y direction. The spring support portion 146 is arranged between the substrate side parallel spring 144 and the case side parallel spring 145. The spring support portion 146 is fixed to both the substrate side parallel spring 144 and the case side parallel spring 145, respectively.

The encoder device 200 configured as described above is the same as in the first embodiment in that when the rotating shaft 102 moves eccentrically, the substrate 41 moves together with the rotating shaft 102. For example, when the substrate 41 moves in the X direction together with the rotating shaft 102, the substrate-side parallel spring 144 elastically deforms in the X direction to allow the substrate 41 to move. Further, for example, when the substrate 41 moves in the Y direction together with the rotating shaft 102, the case-side parallel spring 145 elastically deforms in the Y direction to allow the substrate 41 to move.

Further, the substrate-side parallel spring 144, the case-side parallel spring 145, and the spring support portion 146 restrict the movement of the substrate 41 and the detection portion 20 in the Z direction. In this way, when the rotating shaft 102 moves eccentrically, the connecting unit 143 allows the detection unit 20 to move in the X and Y directions, and detects the detection unit 20 so as to restrict the movement in the Z direction. Supports part 20.

Therefore, when the rotating shaft 102 moves eccentrically, the detection unit 20 moves together with the substrate 41 in the X direction and the Y direction together with the rotating shaft 102. When the rotating shaft 102 moves eccentrically, the rotating portion 10 moves integrally with the rotating shaft 102 in the X and Y directions. Therefore, when the rotation shaft 102 moves eccentrically, the detection unit 20 moves in the X direction and the Y direction following the rotation unit 10 and the pattern 12. In this way, the support unit 140 aligns the detection unit 20 with the pattern 12 of the rotation unit 10 by moving following the movement of the rotation shaft 102.

As described above, the encoder device 200 according to the second embodiment can accurately acquire the rotation information of the rotation shaft 102. In the encoder device 200, the detection unit 20 moves together with the rotating unit 10 and the rotating shaft 102 in the direction (X direction, Y direction) intersecting the central axis AX of the rotating shaft 102, and the rotating shaft 102 moves eccentrically. Also, it is possible to suppress the relative positional relationship between the pattern 12 of the rotating unit 10 and the detecting unit 20 from shifting, and it is possible to acquire the rotation information of the rotating shaft 102 (rotating unit 10) without error.

Further, since the connecting portion 142 uses the substrate side parallel spring 144 and the case side parallel spring 145, when the substrate 41 moves, one or both of the substrate side parallel spring 144 and the case side parallel spring 145 are elastically deformed. There is. Therefore, when the substrate 41 returns to the original position (that is, when the rotating shaft 102 returns to the original position), the substrate 41 is subjected to the elastic force of one or both of the substrate side parallel spring 144 and the case side parallel spring 145. It returns to its original position. By utilizing the elastic force of the substrate-side parallel spring 144 and the case-side parallel spring 145 in this way, the detection unit 20 can be easily made to follow the movement of the rotation shaft 102.

[Third Embodiment]
FIG. 4 is a diagram showing an example of the encoder device 300 according to the third embodiment. FIG. 4A is a cross-sectional view taken along a plane parallel to the XZ plane, and FIG. 4B is a plan view when viewed in the −Z direction. As shown in FIGS. 4A and 4B, the encoder device 300 includes a rotating portion 10, a detecting portion 20, a case portion 30, a supporting portion 40, and a sealing portion 50. The third embodiment is different from the first embodiment in that the seal portion 50 is provided, and the other configurations are the same as those of the first embodiment. In the following description, components that are the same as or equivalent to those in the above-described embodiment are designated by the same reference numerals to omit or simplify the description.

The seal portion 50 is arranged between the substrate 41 and the cylindrical portion 31. The seal portion 50 is formed by using a material capable of elastic deformation such as rubber or resin. The seal portion 50 is elastically deformable with respect to the movement of the substrate 41 in the X direction and the Y direction. The seal portion 50 is provided on the outer circumference of the substrate 41 and the inner circumference of the cylindrical portion 31 without gaps. The seal portion 50 seals the space on the −Z side of the substrate 41 with respect to the space on the + Z side of the substrate 41 among the spaces surrounded by the case portion 30. Since the seal portion 50 can be elastically deformed, the above-mentioned sealing can be maintained by expanding and contracting even when the substrate 41 moves in the X direction and the Y direction.

As described above, the encoder device 300 according to the third embodiment can acquire the rotation information of the rotating shaft 102 with high accuracy as in the first embodiment, and is provided with the seal portion 50. When foreign matter is generated from the ring 47 or the like, it is possible to prevent the foreign matter from adhering to the detection unit 20 or the pattern 12. As a result, the encoder device 300 can maintain the acquisition of highly accurate rotation information for a long period of time.

[Fourth Embodiment]
FIG. 5 is a diagram showing an example of the encoder device 400 according to the fourth embodiment. FIG. 5A is a cross-sectional view taken along a plane parallel to the XZ plane, and FIG. 5B is a plan view when viewed in the −Z direction. As shown in FIGS. 5A and 5B, the encoder device 400 includes a rotating unit 10, a detecting unit 20, a case unit 30, and a supporting unit 340. In the third embodiment, the configuration of the support portion 340 is different from that of the first embodiment, and the other configurations are the same as those of the first embodiment. In the following description, the same or equivalent components as those in the above-described embodiment are designated by the same reference numerals, and the description will be omitted or simplified.

The support portion 340 has a substrate 341, a connection portion 42, and a guide portion 343. The substrate 341 is formed in a disk shape having substantially the same dimensions and shape as, for example, the scale 11. The substrate 341 is arranged so as to be separated from the + Z side of the rotation shaft 102 so that the center position coincides with or substantially coincides with the center axis AX. The substrates 341 are arranged at predetermined intervals in the Z direction with respect to the scale 11. The substrate 341 is arranged parallel to or substantially parallel to the scale 11. The detection unit 20 is attached to the −Z side surface of the substrate 341. The substrate 341 may have a circuit that is electrically connected to the detection unit 20. In the connection portion 42, the substrate side hub 44 is fixed to the + Z side surface of the substrate 341. Since the other configurations of the connecting portion 42 are the same as those of the first embodiment, the description thereof will be omitted.

The guide portion 343 is formed in a cylindrical shape. The guide portion 343 is fixed to the outer edge of the scale 11 and rotates integrally with the scale 11. Further, the inner peripheral surface of the guide portion 343 is in contact with the outer edge of the substrate 341. The substrate 341 is held by the connecting portion 42 and does not rotate even when the guide portion 343 (scale 11) rotates. Since friction is generated between the guide portion 343 and the substrate 341, the contact portion of the inner peripheral surface of the guide portion 343 with the substrate 341 is configured or treated to reduce the friction. May be good. The guide portion 343 has a support portion 343a that supports the substrate 341 in the Z direction. The support portion 343a maintains the distance between the substrate 341 and the scale 11. It should be noted that the guide unit 343 and the drive unit 101 may also be provided with a configuration or process for reducing friction. In this case, for example, a ball may be inserted between the guide portion 343 and the drive portion 101 like a ball bearing in order to convert the sliding friction into rolling friction.

In the encoder device 400 configured as described above, when the rotating shaft 102 moves eccentrically, the rotating portion 10 and the guide portion 343 move integrally with the rotating shaft 102. By the movement of the guide portion 343, the substrate 341 moves in the X direction and the Y direction together with the rotating portion 10 and the guide portion 343. Therefore, even when the rotation shaft 102 moves eccentrically, the detection unit 20 moves in the same direction following this movement. As a result, the detection unit 20 is maintained in a state of being aligned with the pattern 12 of the scale 11 when the rotation shaft 102 is eccentrically moved. That is, it is possible to prevent the detection unit 20 and the pattern 12 from being displaced from each other.

As described above, the encoder device 400 according to the fourth embodiment can accurately acquire the rotation information of the rotation shaft 102 as in the first embodiment. The encoder device 400 can move together with the rotating portion 10 and the rotating shaft 102 in the direction (X direction, Y direction) in which the detecting unit 20 intersects the central axis AX of the rotating shaft 102. Therefore, even when the rotating shaft 102 moves eccentrically, it is possible to prevent the relative positional relationship between the pattern 12 of the rotating portion 10 and the detecting portion 20 from shifting, and the rotation of the rotating shaft 102 (rotating portion 10). Information can be obtained without error.

In this embodiment, the guide portion 343 and the substrate 341 are slidable, but the present invention is not limited to this. For example, a roller, a free ball, or the like may be arranged between the guide portion 343 and the substrate 341 to reduce friction between the two.

[Fifth Embodiment]
FIG. 6 is a diagram showing an example of the encoder device 500 according to the fifth embodiment. FIG. 6A is a cross-sectional view taken along a plane parallel to the XZ plane, and FIG. 6B is a plan view when viewed in the −Z direction. As shown in FIGS. 6A and 6B, the encoder device 500 includes a rotating unit 10, a detecting unit 20, a case unit 30, and a supporting unit 440. In the fifth embodiment, the substrate 441 configuration of the support portion 440 is different from that of the fourth embodiment, and other configurations are the same as those of the fourth embodiment. In the following description, the same or equivalent components as those in the above-described embodiment are designated by the same reference numerals, and the description will be omitted or simplified.

The support portion 440 has a substrate 441, a connection portion 42, and a guide portion 343. The substrate 441 has a disk shape, and the outer diameter is formed to be smaller than that of the scale 11. The detection unit 20 is attached to the −Z side surface of the substrate 441. The substrate 441 may have a circuit that is electrically connected to the detection unit 20. The substrates 441 are arranged at predetermined intervals in the Z direction with respect to the scale 11. The substrate 441 is arranged parallel to the scale 11.

A plurality of projecting portions 441a are provided on the outer peripheral portion of the substrate 441 so as to project outward in the radial direction and abut on the inner peripheral surface of the guide portion 343. A plurality of protrusions 441a are provided at predetermined intervals in the direction around the axis of the central axis AX. In the present embodiment, an example is given in which three protrusions 441a are provided at equal intervals in the direction around the axis of the central axis AX, but the present invention is not limited to this, and two or four or more protrusions are provided. It may be provided at unequal intervals around the central axis AX.

In the connection portion 42, the substrate side hub 44 is fixed to the + Z side surface of the substrate 441. Since the other configurations of the connecting portion 42 are the same as those of the above-described embodiments and the guide portion 343 is the same as the fourth embodiment, the description thereof will be omitted.

In the encoder device 500 configured as described above, when the rotating shaft 102 moves eccentrically, the rotating portion 10 and the guide portion 343 move integrally with the rotating shaft 102. By the movement of the guide portion 343, the substrate 441 moves in the X direction and the Y direction together with the rotating portion 10 and the guide portion 343. Therefore, even when the rotation shaft 102 moves eccentrically, the detection unit 20 moves in the same direction following this movement. As a result, the detection unit 20 is maintained in a state of being aligned with the pattern 12 of the scale 11 when the rotation shaft 102 is eccentrically moved. That is, it is possible to prevent the detection unit 20 and the pattern 12 from being displaced from each other.

As described above, the encoder device 500 according to the fifth embodiment can accurately acquire the rotation information of the rotation shaft 102 as in the fourth embodiment. Further, in the encoder device 500, the substrate 441 and the guide portion 343 are partially in contact with each other by the protruding portion 441a. Therefore, the friction between the substrate 441 and the guide portion 343 is reduced as compared with the case where the entire outer edge of the substrate is in contact with the guide portion 343.

In the present embodiment, the protruding portion 441a and the guide portion 343 are sliding, but the present invention is not limited to this. For example, a roller, a free ball, or the like may be arranged at the tip of the protruding portion 441a to reduce friction between the two. Further, the protruding portion 441a is formed in an arc shape when viewed from the Z direction, but the present invention is not limited to this. For example, the protrusion 441a may be formed in a triangular shape when viewed from the Z direction.

[Sixth Embodiment]
FIG. 7 is a diagram showing an example of the encoder device 600 according to the sixth embodiment, and is a cross-sectional view taken along the plane parallel to the XZ plane. As shown in FIG. 7, the encoder device 600 includes a rotating unit 10, a detecting unit 20, a case unit 30, and a supporting unit 540. In the sixth embodiment, the configuration of the support portion 540 is different from that of the first embodiment, and the other configurations are the same as those of the first embodiment. In the following description, the same or equivalent components as those in the above-described embodiment are designated by the same reference numerals, and the description will be omitted or simplified.

The support portion 540 includes a substrate 541, a connection portion 42, a centering bearing 543, an elastic member 551, a support plate 552, a gap bearing 555, and an absorption portion 554. The substrate 541 is formed in a disk shape. The detection unit 20 is attached to the −Z side surface of the substrate 541. The substrate 541 may have a circuit that is electrically connected to the detection unit 20. The substrate 541 is arranged in parallel with the scale 11 at a predetermined distance in the Z direction with respect to the scale 11 by a gap bearing 553 described later.

The substrate 541 is arranged so that the center substantially coincides with the central axis AX, and the central portion is open. A cylindrical bearing support portion 541a is provided in the opening portion of the substrate 541. In the connection portion 42, the substrate side hub 44 is fixed to the + Z side surface of the substrate 541. Further, in the connecting portion 42, the case-side hub 46 is fixed to the lid portion of the case portion 30 via the absorbing portion 554. Since the other configurations of the connecting portion 42 are the same as those of the above-described embodiments, the description thereof will be omitted.

In the centering bearing 543, the inner ring is attached to the rotating shaft 102, and the outer ring is fixed to the bearing support portion 541a. Therefore, the substrate 541 is held by the rotating shaft 102 via the centering bearing 543, and does not rotate even when the rotating shaft 102 rotates. Further, the centering bearing 543 allows the substrate 541 to move in a direction inclined with respect to a plane orthogonal to the central axis AX.

For example, a coil spring or the like is used as the elastic member 551, and the elastic member 551 is arranged between the substrate 541 and the support plate 552. The support plate 552 is formed in a disk shape, for example, and is fixed to a cylindrical portion 31 of the case portion 30, for example. An opening 552a is formed in the central portion of the support plate 552. The opening 552a has a diameter larger than the diameter of the rotating shaft 102 at least. As shown in FIG. 7, the opening 552a may have a diameter larger than, for example, the outer diameter of the bearing support portion 541a. For example, the elastic member 551 exerts an elastic force on the substrate 541 in the −Z direction, and the substrate 541 is pressed against the rotating portion 10 by the elastic force. The number or arrangement of the elastic members 551 is arbitrary.

The gap bearing 553 is arranged between the substrate 541 and the scale 11. The gap bearing 553 maintains a distance between the substrate 541 and the scale 11 in the Z direction. The gap bearing 553 rotatably supports the scale 11 with respect to the substrate 541. The gap bearings 553 are arranged at three places around the central axis AX, for example, but the number or arrangement is arbitrary as long as the distance between the substrate 541 and the scale 11 can be maintained.

The absorbing portion 554 is formed by using an elastically deformable material such as rubber. The absorption unit 554 is used to absorb the movement or inclination of the Oldham coupling 47 in the Z direction. However, it is optional whether or not the absorption unit 554 is arranged, and the absorption unit 554 may not be provided. If the absorption unit 554 is not arranged, the movement or inclination of the Oldham coupling 47 in the Z direction may be absorbed in the Oldam coupling 47.

FIG. 8A is a diagram showing a state in which the rotation shaft 102 of the encoder device 600 is tilted. In FIG. 8A, some configurations are omitted. As shown in FIG. 8A, in the encoder device 600, when the rotating shaft 102 is tilted, the scale 11 is tilted integrally with the rotating shaft 102. At this time, the substrate 541 is pressed toward the scale 11 by the elastic force of the elastic member 551, and is tilted by the gap bearing 553 in the same manner as the scale 11.

Since the substrate 541 is tilted, the Oldham coupling 47 is also tilted, but this tilt is absorbed by the absorption portion 554 being deformed. The distance between the substrate 541 and the scale 11 is maintained by the gap bearing 553. In this case, since the substrate 541 is pressed against the scale 11 side by the elastic force of the elastic member 551, it is possible to prevent the substrate 541 from being separated from the gap bearing 553 on the + Z side. In this way, the relative positional relationship between the scale 11 and the detection unit 20 is maintained. Therefore, even when the rotation axis 102 is tilted from the Z direction, the detection unit 20 accurately reads the pattern 12, so that the detection error can be suppressed.

FIG. 8B is a diagram showing a state in which the rotation axis 102 of the encoder device 600 moves in the axial direction of the central axis AX. In FIG. 8 (B), a part of the configuration is omitted as in FIG. 8 (A). As shown in FIG. 8B, when the rotating shaft 102 moves in the axial direction of the central axis AX, the encoder device 600 follows the movement of the rotating portion 10 in the Z direction by the elastic member 551 and the gap bearing 553. The substrate 541 also moves in the Z direction. At this time, the Oldham coupling 47 also moves in the Z direction, but this movement is absorbed by the absorption unit 554 being deformed. In this way, the relative positional relationship between the scale 11 and the detection unit 20 is maintained. Therefore, even when the rotation shaft 102 is moved in the Z direction, the detection unit 20 accurately reads the pattern 12, so that the detection error can be suppressed.

Further, although not shown, the rotating shaft 102 may not be tilted and the substrate 541 may be tilted with respect to a plane (XY plane) orthogonal to the central axis AX. Since the substrate 541 is supported by the centering bearing 543, it can swing in the Z direction with respect to the rotating shaft 102. Therefore, even when the substrate 541 is tilted with respect to the rotating shaft 102, the substrate 541 follows the tilt of the rotating portion 10 by the elastic member 551 and the gap bearing 553, as in FIG. 8A described above. Is also tilted. As a result, the relative positional relationship between the scale 11 and the detection unit 20 is maintained, and the detection unit 20 accurately reads the pattern 12 even when the rotating unit 10 is tilted, so that a detection error can be suppressed. ..

As described above, the encoder device 600 according to the sixth embodiment can accurately acquire the rotation information of the rotation shaft 102 as in the first embodiment. The encoder device 600 has a detection unit 20 even when the rotating shaft 102 is tilted in the Z direction, the rotating shaft 102 moves in the Z direction, or the rotating unit 10 is tilted with respect to the rotating shaft 102. Moves following the rotating unit 10, so that the relative positional relationship between the pattern 12 of the rotating unit 10 and the detecting unit 20 is suppressed from shifting, and the rotation information of the rotating shaft 102 (rotating unit 10) can be obtained without error. Can be obtained. In the sixth embodiment, the centering bearing 543 is used, but the present invention is not limited to this, and bearings of other forms may be used.

[7th Embodiment]
FIG. 9 is a diagram showing an example of the encoder device 700 according to the seventh embodiment. FIG. 9A is a cross-sectional view taken along a plane parallel to the XZ plane, and FIG. 9B is a plan view when viewed in the −Z direction. As shown in FIGS. 6A and 6B, the encoder device 700 includes a rotating unit 10, a detecting unit 20, a case unit 30, and a supporting unit 640. In the seventh embodiment, the configuration of the support portion 640 is different from that of the first embodiment, and the other configurations are the same as those of the first embodiment. In the following description, the same or equivalent components as those in the above-described embodiment are designated by the same reference numerals, and the description will be omitted or simplified.

The support portion 640 has a plurality of drive elements 641 and an element support portion 642. Each of the drive elements 641 is attached to the detection unit 20. As the drive element 641, for example, a piezoelectric element or the like is used. The plurality of drive elements 641 move the detection unit 20 in the X direction, the Y direction, the Z direction, the rotation direction about the X direction, the rotation direction about the Y direction, and the rotation direction about the Z direction. Arranged so that it can be. For each of the drive elements 641, for example, the drive amount or drive timing is controlled by the control unit 650. The drive element 641 is supported by the cylindrical portion 31 and the lid portion 32 of the case portion 30 via the element support portion 642.

As shown in FIG. 9A, the encoder device 700 may include a sensor 651 that detects eccentric movement, inclination, and movement of the rotating shaft 102 in the Z direction and outputs the detection result to the control unit 650. Good. The sensor 651 may detect the eccentric movement of the rotating shaft 102 by detecting a part of the rotating portion 10 instead of the rotating shaft 102.

The control unit 650 drives the drive element 641 based on the detection result of the sensor 651, and moves the detection unit 20 to control the relative positions of the pattern 12 of the rotating unit 10 and the detection unit 20 so as not to fluctuate. It is optional whether or not the sensor 651 is arranged. In the absence of the sensor 651, the control unit 650 may drive each drive element 641 based on the control content stored in a storage unit (not shown). Further, the control unit 650 calculates, for example, the eccentric movement of the rotation shaft 102 from the phase difference between the incremental pattern and the absolute pattern in the pattern 12 based on the detection result in the detection unit 20, and uses this calculation result. Each drive element 641 may be driven.

As described above, the encoder device 700 according to the seventh embodiment can accurately acquire rotation information. The encoder device 700 can make the detection unit 20 follow the movement of the rotation shaft 102 (rotation unit 10) by the drive element 641 and the control unit 650. Therefore, it is possible to suppress the relative positional relationship between the pattern 12 of the rotating unit 10 and the detecting unit 20 from shifting, and to acquire the rotation information of the rotating shaft 102 (rotating unit 10) without error.

[Drive]
Next, the drive device will be described. FIG. 10 is a diagram showing an example of the drive device MTR. In the following description, the same or equivalent components as those in the above-described embodiment are designated by the same reference numerals, and the description will be omitted or simplified. This drive device MTR is a motor device including an electric motor. The drive device MTR includes a rotation shaft 102, a main body (drive unit) BD that rotationally drives the rotation shaft 102, an encoder device EC that detects rotation information of the rotation shaft 102, and a control unit MC that controls the main body BD. , Equipped with.

The rotating shaft 102 has a load-side end SFa and a non-load-side end SFb. The load side end SFa is connected to another power transmission mechanism such as a speed reducer. A scale (not shown) is fixed to the counter-load side end SFb. The encoder device EC is the encoder device described in the above-described embodiment.

In this drive device MTR, the control unit MC controls the main body unit BD using the detection result of the encoder device EC. Since the drive device MTR controls the main body BD using the rotation information in which the error is suppressed, the rotation position of the rotation shaft 102 can be controlled with high accuracy. The drive device MTR is not limited to the motor device, and may be another drive device having a shaft portion that rotates by utilizing hydraulic pressure or pneumatic pressure.

[Stage device]
Next, the stage device will be described. FIG. 11 is a diagram showing a stage device STG. This stage device STG has a configuration in which a rotary table (moving object) TB is attached to the load side end SFa of the rotary shaft 102 of the drive device MTR shown in FIG. In the following description, the same or equivalent components as those in the above-described embodiment are designated by the same reference numerals, and the description will be omitted or simplified.

When the stage device STG drives the drive device MTR to rotate the rotation shaft 102, this rotation is transmitted to the rotary table TB. At that time, the encoder device EC detects rotation information (eg, rotation position) of the rotation shaft 102. Therefore, the angular position of the rotary table TB can be detected by using the output from the encoder device EC. A speed reducer or the like may be arranged between the load side end SFa of the drive device MTR and the rotary table TB.

In this way, the stage device STG can accurately control the position of the rotary table TB because the error is suppressed in the rotation information output by the encoder device EC. The stage device STG can be applied to, for example, a rotary table provided in a machine tool such as a machining center.

[Robot device]
Next, the robot device will be described. FIG. 12 is a perspective view showing the robot device RBT. Note that FIG. 12 schematically shows a part (joint portion) of the robot device RBT. In the following description, the same or equivalent components as those in the above-described embodiment are designated by the same reference numerals, and the description will be omitted or simplified. This robot device RBT has a first arm AR1, a second arm AR2, and a joint portion JT. The first arm AR1 is connected to the second arm AR2 via the joint JT.

The first arm AR1 includes an arm portion 104, a bearing 104a, and a bearing 104b. The second arm AR2 has an arm 105 and a connecting 105a. The connecting portion 105a is arranged between the bearing 104a and the bearing 104b in the joint portion JT. The connecting portion 105a is provided integrally with the rotating shaft SF2. The rotary shaft SF2 is inserted into both the bearing 104a and the bearing 104b at the joint portion JT. The end of the rotating shaft SF2 on the side inserted into the bearing 104b penetrates the bearing 104b and is connected to the speed reducer RG.

The speed reducer RG is connected to the drive device MTR, and reduces the rotation of the drive device MTR to, for example, 1/100 or the like and transmits it to the rotation shaft SF2. Although not shown in FIG. 12, the load side end of the rotating shaft 102 of the drive device MTR is connected to the speed reducer RG. Further, a scale (not shown) of the encoder device EC is attached to the counter-load side end of the rotating shaft 102 of the drive device MTR.

When the robot device RBT drives the drive device MTR to rotate the rotation shaft 102, this rotation is transmitted to the rotation shaft SF2 via the speed reducer RG. The rotation of the rotation shaft SF2 causes the connection portion 105a to rotate integrally, whereby the second arm AR2 rotates with respect to the first arm AR1. At that time, the encoder device EC detects rotation information (eg, rotation position, etc.) of the rotation shaft 102. Therefore, the angular position of the second arm AR2 can be detected by using the output from the encoder device EC.

In this way, in the robot device RBT, since the encoder device EC outputs the rotation information in which the error is suppressed, the relative positions of the first arm AR1 and the second arm AR2 can be accurately controlled. The robot device RBT is not limited to the above configuration, and the drive device MTR can be applied to various robot devices having joints.

Although the embodiments of the present invention have been described above, the technical scope of the present invention is not limited to the embodiments described in the above-described embodiments and the like. One or more of the requirements described in the above embodiments and the like may be omitted. In addition, the requirements described in the above-described embodiments can be combined as appropriate.

Further, the above embodiment has one detection unit 20, but is not limited to this. For example, two or more detection units 20 may be arranged. In this case, each detection unit 20 may be supported by the same support unit 40 (board 41) or the like, or may be supported by a separately formed support unit (board).

Further, the above-described embodiment shows a configuration in which the pattern 12 of the rotating portion 10 (scale 11) attached to the rotating shaft 102 is detected by the detecting portion 20 held by the case portion 30, but is limited to this. Not done. For example, the detection unit 20 may be fixed to the rotating unit 10 and the pattern 12 may be formed on the substrate 41 or the like of the support unit 40. Even in this case, when the rotation shaft 102 moves, the pattern 12 also moves, and the detection unit 20 follows the movement of the pattern 12. Therefore, since the relative positions of the detection unit 20 and the pattern 12 do not change, the rotation information of the rotation shaft 102 (rotation unit 10) can be acquired without error.

AX ... central axis, MTR ... drive device, BD ... main body, EC, 100, 200, 300, 400, 500, 600, 700 ... encoder device, STG ... stage device, RBT ... Robot device, 10 ... Rotating part, 11 ... Scale, 12 ... Pattern, 20 ... Detection part, 30 ... Case part, 40, 340, 440, 540, 640 ...・ Support part, 41, 341, 441, 541 ... Substrate, 42 ... Connection part, 43 ... Bearing, 47 ... Oldham coupling, 50 ... Seal part, 543 ... Alignment Bearing, 551 ... Elastic member, 535 ... Gap bearing, 554 ... Absorbent

Claims (15)

A rotating part that is fixed to the rotating shaft of the measurement target and has a pattern formed on it,
A detecting unit that issues test the pattern,
A substrate on which the detection unit is attached and allowing rotation of the rotating portion, a connecting portion that connects between the case accommodating the rotating portion and the substrate, and a connecting portion that follows the movement of the rotating shaft. An encoder device comprising, and a support having . The encoder device according to claim 1 , wherein the substrate is arranged in parallel with the rotating portion at a predetermined interval. The encoder device according to claim 1 or 2 , wherein the substrate is held by the rotating shaft via a bearing. The encoder device according to claim 1 or 2 , wherein the substrate is held inside a tubular guide portion arranged so as to surround the outer periphery of the rotating portion. The encoder device according to claim 4 , wherein the substrate contacts the guide portion at a plurality of locations at intervals in the circumferential direction. The substrate is held by the rotating shaft via a centering bearing.
The encoder device according to claim 1 or 2 , wherein a gap bearing for maintaining a distance between the substrate and the rotating portion is arranged. The encoder device according to claim 6 , further comprising an elastic member that presses the substrate toward the rotation axis. The connecting portion in the rotation axis in a plane perpendicular to the axial direction of, formed by including a two-way movable to each other such Oldham couplings which are orthogonal, in any one of claims 1 to 7 The encoder device described. Said connecting portion, said being in a direction perpendicular to the axial direction of the rotary shaft is formed to include an elastically deformable parallel springs, encoder device as claimed in any one of claims 1 to 7. Comprising a seal between the substrate and the casing, the encoder apparatus according to any one of claims 1 to 9. The pattern is an optical pattern
The detector detects the reflected light or transmitted light by the optical pattern, the encoder apparatus according to any one of claims 1 0 to claim 1. The pattern is a magnetic pattern
The detecting unit detects a magnetic field by said magnetic pattern, an encoder apparatus according to any one of claims 1 0 to claim 1. Claims 1 and encoder device according to any one of claims 1 2,
And a driving unit for supplying a driving force to the rotary shaft, the driving device. With a mobile body
And a driving device according to claim 1 3 for moving the mobile stage device. A driving device according to claim 1 3, the robotic device.

Images