Encoder device, encoder device installation method, torque limiting mechanism, drive device and robot device

Abstract

A drive device (1) comprising a driver (41), a rotary shaft (42) rotatable about a predetermined axial line (C) by being driven by the driver (41), an output shaft (27) which is rotatable about the predetermined axial line (C) and which can output at least part of the rotation of the rotary shaft (42), and an encoding device (60) configured to detect rotation information of the rotary shaft (42) and the output shaft (27), the encoding device (60) comprising: a first encoder (61) comprising: a first rotating device (611) which is attached to the rotating shaft (42) and which has a first pattern (631), a first substrate (612) supported by a first frame means (691), wherein the first frame means (691) is supported by a non-rotating surface (41a) of the driver (41), wherein a portion of the housing of the driver (41) has the non-rotating surface (41a), and the non-rotating surface (41a) is formed in a circular shape when viewed in the axial direction, wherein the first substrate (612) has a detection surface (612a) facing the first rotating device (611), and wherein a through-hole (612f) is formed in a central portion of the first substrate (612) and the output shaft (27) extends in the axial direction through the through-hole (612f), a light emitting and receiving element (613) and a magnetism detecting element (614) installed on the first substrate (612), wherein the light emitting and receiving element (613) and the magnetism detecting element (614) are provided on the detecting surface (612a) of the first substrate (612), a first detector unit (617) positioned on a non-rotating device and arranged to detect the first pattern (631), a second encoder (62) comprising: a second rotating device (621) which is attached to the output shaft (27) and which has a second pattern (641), a second substrate (622) supported by a second frame means (692), wherein the second frame means (692) is supported by the non-rotating surface (41a) of the driver (41), wherein the second substrate (622) has a detection surface (622a) directed towards the second rotating device (621), a light emitting and receiving element (623) installed on the second substrate (622), wherein the light emitting and receiving element (623) is provided on the detection surface (622a) of the second substrate (622), a second detector unit (624) positioned on the non-rotating device and configured to detect the second pattern (641), and a reference unit (600) which is attached to the non-rotating surface (41a) of the driver (41) and which has a common position reference (600a), wherein the reference unit (600) is formed in a ring shape, wherein the common position reference (600a) is provided on a cylindrical surface whose center forms the predetermined axial line (C) and which is an outer peripheral surface (600a) of the reference unit (600), wherein an inner surface (691a) of the first frame means (691) faces and adjoins the outer peripheral surface of the reference unit (600) and an inner surface (692a) of the second frame means (692) faces and adjoins the outer peripheral surface of the reference unit (600), so that the reference unit (600) positions the first detector unit (617) and the second detector unit (624) by means of the common position reference (600a), wherein the inner surface (691a) of the first frame means (691) has the same diameter as the outer peripheral surface (600a), and wherein the inner surface (692a) of the second frame means (692) has the same diameter as the outer peripheral surface (600a).

Description

Technical area

[0001] The present invention relates to an encoder, an encoder installation method, a torque limiting mechanism, a drive device, and a robot device. background

[0002] In a driver of an industrial robot, a machine tool, or the like where high positioning accuracy is required, a geared motor configured to output the rotation of the motor through a reduction gear having high transmission accuracy can be used. As an example of the geared motor, JP 2001-241462 A discloses a motor comprising a motor main body, a reduction gear connected in a coaxial state to a rotating shaft of the motor main body, and an output shaft connected in a coaxial state to an output side of the reduction gear.

[0003] In the motor described above, it is necessary to control the rotation angle of the output shaft of the reduction gear with high precision in order to precisely perform positioning or similar tasks. Accordingly, a first encoder is mounted on the motor's rotating shaft, and a second encoder is mounted on the output shaft.

[0004] An exemplary drive unit is known from WO 2007 / 082594 A2. An exemplary geared motor unit is known from US 8 384 260 B2. An exemplary lightweight electric robot drive is known from EP 0 146 783 A2. An exemplary torque sensor and an exemplary robot device are known from US 2011 / 0 239 788 A1. Brief description of the invention Tasks to be solved by the invention

[0005] However, in the motor described above, the first encoder and the second encoder are positioned so that they are arranged in an axial direction. Accordingly, positioning between the scales of the first encoder and the second encoder and a detector unit is difficult, and therefore, there is a problem that an assembly process quickly becomes difficult.

[0006] It is an object of the present invention to provide an encoder, an encoder installation method, a torque limiting mechanism, a drive device and a robot device that can be easily assembled. Means of solving the task

[0007] According to the present invention, a driving device according to claim 1 and a robot device according to claim 10 are provided.

[0008] According to a first embodiment, an encoder is provided comprising a first rotary device that can be attached to a rotary shaft and has a first pattern, the rotary shaft being rotatable about a predetermined axial line, a first detector unit positioned on a non-rotating device and configured to detect the first pattern, a second rotary device that is attached to an output shaft and has a second pattern, the output shaft being rotatable about the predetermined axial line and capable of outputting at least part of the rotation of the rotary shaft, a second detector unit positioned on the non-rotating device and configured to detect the second pattern, and a reference unit configured to position the first detector unit and the second detector unit using a common position reference.

[0009] According to a second exemplary embodiment, an encoder device is provided, comprising a first shaft which is either a rotary shaft or an output shaft and which has a hollow portion or a hollow means, wherein the rotary shaft is rotatable about a predetermined axial line, wherein the output shaft is rotatable about the predetermined axial line and outputs or inputs at least a portion of the rotation of the rotary shaft.can output, a second shaft which is different from the first shaft and is the other of the rotary shaft and the output shaft, which is configured to penetrate into the hollow portion and which is provided to protrude from one end of the first shaft, a first rotary device which is provided at one end of the first shaft and which has the first pattern, a second rotary device which is provided at a portion of the second shaft which protrudes from the first shaft and which has a second pattern, a first detecting unit which is configured to detect the first pattern, and a second detecting unit which is configured to detect the second pattern, wherein the encoder is configured to detect rotation information of a drive source which drives a joint of a robot device having an arm.

[0010] According to a third exemplary embodiment, an encoder installation method is provided, comprising a first fastening process of fastening a first rotating device having a first pattern to a rotating shaft that can rotate about a predetermined axial line; a first arranging process of arranging a first detector unit to a non-rotating device such that the first detector unit is positioned by means of a predetermined position reference arranged on a reference unit, wherein the first detector unit can detect the first pattern; a second fastening process of fastening a second rotating device having a second pattern to an output shaft that can rotate about the predetermined axial line and that can output at least part of the rotation of the rotating shaft;and a second arranging process of arranging a second detector unit on the non-rotating device so that the second detector unit is positioned by means of the position reference, wherein the second detector unit can detect the second pattern.

[0011] According to a fourth exemplary embodiment, a torque limiting mechanism is provided, including a rotary shaft that can be rotated about a predetermined axial line by being driven by a driver, an output shaft that can be rotated about the predetermined axial line and that outputs at least part of the rotation of the rotary shaft, a connecting portion configured to connect the rotary shaft and the output shaft and to displace / translate the rotary shaft and the output shaft relative to each other when the torque transmitted from the rotary shaft to the output shaft exceeds a predetermined value, and an encoder configured to detect rotation information of the rotary shaft and the output shaft, wherein the encoder device according to the first or second aspect is used as the encoder device.

[0012] According to a fifth exemplary embodiment, a drive device is provided, comprising a driver, a rotary shaft that can be rotated about a predetermined axial line by being driven by the driver, an output shaft that can be rotated about the predetermined axial line and outputs at least a part of the rotation of the rotary shaft, and an encoder configured to detect rotation information of the rotary shaft and the output shaft, wherein the encoder according to the first or second aspect is used as the encoder.

[0013] According to a sixth exemplary embodiment, a robot device is provided which comprises an arm and a driving device configured to drive the arm, wherein the driving device according to the fifth exemplary embodiment is used as the driving device. Advantage of the invention

[0014] According to aspects of the present invention, a driving device and a robot device may be provided. Short description of the characters Fig. 1 is a sectional view showing a structure of an encoding device according to a first embodiment. Fig. 2 is a perspective view showing the structure of the coding device according to the present embodiment. Fig. 3 is an exploded perspective view showing the structure of the coding device according to the present embodiment. Fig. 4 is a flowchart showing an assembling method of the encoder device according to the present embodiment. Fig. 5 is a perspective view showing an assembling process of the encoder device according to the present embodiment. Fig. 6 is a perspective view showing the assembling process of the encoder device according to the present embodiment. Fig. 7 is a perspective view showing the assembling process of the encoder device according to the present embodiment. Fig. 8 is a perspective view showing the assembling process of the encoder device according to the present embodiment. Fig. 9 is a perspective view showing the assembling process of the encoder device according to the present embodiment. Fig. 10 is a perspective view showing the structure of a driving device and that of a robot device according to a second embodiment. Fig. 11 is a block diagram showing the structure of the drive device and that of the robot device according to the second embodiment. Fig. 12 is a block diagram showing the structure of the drive device according to the second embodiment. Fig. 13 is a graph showing an operating characteristic of the drive device and one of the robot device according to the second embodiment. Description of embodiments

[0015] In the following, embodiments of the present invention will be described with reference to the figures. [First embodiment]

[0016] The Fig. Fig. 1 is a sectional view showing a structure of an encoding device (encoder) 60 according to a first embodiment of the present invention. Fig. Fig. 2 is a perspective view showing an outline of the encoder 60. The Fig. 3 is an exploded perspective view showing the outline of the encoder 60.

[0017] As it is in the Fig. As shown in Figures 1 to 3, the encoder 60 includes a first encoder 61 and a second encoder 62. The encoder 60 can separately detect rotation information of a drive shaft (rotation shaft) 42 and an output shaft 27.

[0018] As it is in the Fig. 1 and Fig. As shown in Figure 3, the drive shaft 42 is cylindrically formed and has a hollow portion 42a. The drive shaft 42 is connected to a driver 41. The drive shaft 42 is rotated by a driving force of the driver 41 about an axial line C, which becomes a center axis of the drive shaft 42. An outer ring of a bearing 66 (bearing portion) is inserted into the hollow portion 42a. The drive shaft 42 can be rotated by a driving device.

[0019] The output shaft 27 is cylindrically formed. The output shaft 27 is connected to the drive shaft 42 via a power transmission mechanism (not shown) and outputs at least part of the rotation of the drive shaft 42. The output shaft 27 is provided so as to penetrate into the hollow portion 42a of the drive shaft 42. The output shaft 27 is fitted into an inner ring of the bearing 66. The output shaft 27 is arranged to rotate about the axial line C, which it shares with the drive shaft 42, via the bearing 66 and can be rotated independently with respect to the drive shaft 42. A tip (upper end in the drawings) 27a of the output shaft 27 protrudes from the drive shaft 42.

[0020] The first encoder 61 detects first position information indicating a rotational position of the drive shaft 42. The first encoder 61 includes a first disk 611 (first rotating device), a first substrate 612, a light emitting and receiving element 613 and a magnetism detecting element 614 installed on the first substrate 612, and a magnet 615 (magnetic field generator). The first encoder 61 outputs the detected position information as the first position information.

[0021] The first disk 611 is fixed to the drive shaft 42 by means of a screw portion 68 and a fixing member 63, and is rotated integrally with the drive shaft 42. For example, a light-reflecting pattern 631 (first pattern) is formed in the first disk 611 along a rotation direction of the first disk 611 to obtain absolute position information (rotational position information) of the drive shaft 42 with a 20-bit resolution.

[0022] The light emitting and receiving element 613 irradiates light onto the above-described light-reflecting pattern 631 of the first disk 611, reads the light reflected by the light-reflecting pattern 631, and outputs a first position detection signal.

[0023] The magnet 615 is attached to the first disk 611. For example, the magnet 615 is formed in a ring shape. A magnetic pattern 632 is formed in the magnet 615 for detecting the amount of multiple rotation of the drive shaft 42 along the rotation direction of the first disk 611.

[0024] The magnetism detection element 614 is positioned at a position on a detection surface 612a of the first substrate 612 that corresponds to the magnet 615. The magnetism detection element 614 detects a magnetic field generated by the magnet 615 and outputs a multi-rotation detection signal.

[0025] A rear yoke 616 is positioned on a surface on the Z-axis side of the first disk 611. For example, the rear yoke 616 is formed using a soft magnetic material. The rear yoke 616 dampens at least part of the magnetism acting from the driver 41 toward the first encoder 61 side and stabilizes a magnetic property of the magnet 615.

[0026] The first substrate 612 has a detection surface 612a facing the first disk 611. The light emitting and receiving element 613 and the magnetism detecting element 614 are provided on the detection surface 612a. A through-hole 612f is formed in a central portion of the first substrate 612. The output shaft 27 extends in the +Z direction of the axial line (the side opposite the driver 41) through the through-hole 612f. The first substrate 612 is supported by a first frame 691. The first frame 691 is supported by a non-rotating surface 41a of the driver 41. In addition, a portion of the housing of the driver 41 has the non-rotating surface 41a, and the non-rotating surface 41a is formed in a circular shape when viewed in the direction of the Z-axial line (see Fig. 3).

[0027] As it is in the Fig. As shown in Figure 3, the first substrate 612 has grooves 612c on the outer peripheral portion of the disk. For example, the grooves 612c are each provided at intervals of 120° in the circumferential direction, that is, are provided at a total of three positions. Accordingly, the first substrate 612 has projections 612d that protrude in the radial direction with respect to the grooves 612c. The first frame device 691 supports each projection 612d of the first substrate 612.

[0028] The first frame means 691 is curved along the circumferential shape of the non-rotating surface 41a. In each first frame means 691, an inner surface 691a, which faces the first disc 611, forms a portion of a cylindrical surface. Each projection 612d is secured, together with the first frame means 691, to the non-rotating surface 41a of the driver 41 by means of a fastening element 612e, such as a screw.

[0029] In addition, the second encoder 62 detects second position information indicating the rotational position of the output shaft 27. The second encoder 62 includes a second disk 621 (second rotating device), a second substrate 622, and a light emitting and receiving element 623 installed on the second substrate 622.

[0030] The second disk 621 is fixed to the output shaft 27 by means of a sleeve 64 at a portion protruding from the first substrate 612 in the +Z direction of the axial line. The sleeve 64 is fixed via a screw portion 67 by means of a nut 65. Accordingly, pressure is applied to the bearing 66. Similar to the first disk 611, for example, a light-reflecting pattern 641 (second pattern) for obtaining absolute position information (rotational position information) with a 20-bit resolution is formed in the second disk 621 along a rotation direction of the second disk 621.

[0031] The light emitting and receiving element 623 reads the above-described light-reflecting pattern 641 of the second disk 621 and outputs a second position detection signal. Thus, the encoder device 60 of the present embodiment has the structure in which a two-stage disk (first disk 611 and second disk 621) is coaxially positioned.

[0032] The second substrate 622 has a detection surface 622a facing the second disk 621. The light emitting and receiving element 623 is provided on the detection surface 622a. The second substrate 622 is supported by a second frame 692. The second frame 692 is supported by the non-rotating surface 41a of the driver 41.

[0033] As it is in the Fig. 3, the second frame means 692 includes a cylindrical portion 692m formed along the outer periphery of the second substrate 622 and a protrusion 692n protruding in the -Z-axis direction from the cylindrical portion 692m. The cylindrical portion 692m is provided to surround the second disk 621. The protrusion 692n is sandwiched between the first frame means 691 and supported by the peripheral edge of the non-rotating surface 41a. The second substrate 622 is fixed to the non-rotating surface 41a of the driver 41 by fastening members 622e, such as a screw, extending over the cylindrical portion 692m and the protrusion 692n of the second frame means 692.

[0034] As it is in the Fig. As shown in Fig. 2, the first frame means 691 and the projection 692n come into contact with each other such that no gap exists between the first frame means 691 and the projection 692n when the projection 692n is inserted between the first frame means 691. In the second frame means 692, which has the cylindrical portion 692m and the projection 692n, an inner surface 692a is formed from the same / common cylindrical surface.

[0035] As it is in the Fig. 1 and Fig. As shown in Figure 3, a reference unit 600 is attached to the non-rotating surface 41a of the driver 41 by means of a connecting means (not shown) or the like. The reference unit 600 is formed in a ring shape, and an outer peripheral surface 600a becomes the cylindrical surface. The reference unit 600 is positioned so that the center of the outer peripheral surface 600a coincides with the axial line C.

[0036] The inner surface 691a of the first frame device 691 abuts the outer peripheral surface 600a. In the present embodiment, the inner surface 691a has the same diameter as the outer peripheral surface 600a. Accordingly, the inner surface 691a abuts the outer peripheral surface 600a, thereby positioning the first frame device 691 and the reference unit 600.

[0037] Additionally, the inner surface 692a of the second frame device 692 abuts the outer peripheral surface 600a. In the present embodiment, the inner surface 692a has the same diameter as the outer peripheral surface 600a. Accordingly, the inner surface 692a abuts the outer peripheral surface 600a, which is why the second frame device 692 and the reference unit 600 are positioned.

[0038] As described above, the first frame device 691 and the second frame device 692 are positioned by sharing the same outer peripheral surface 600a. Accordingly, the outer peripheral surface 600a becomes a common reference position between the first frame device 691 and the second frame device 692.

[0039] In addition, as stated in the Fig. 1, a recessed portion 612b (first recessed portion) is provided on the detection surface 612a of the first substrate 612. A protrusion portion 691b (first protrusion portion) is provided on the +Z-axis side surface of the first frame member 691. The protrusion portion 691b is fitted into the recessed portion 612b. The protrusion portion 691b and the recessed portion 612b are engaged with each other, thus positioning the first substrate 612 and the first frame member 691. In this way, by means of the protrusion portion 691b and the recessed portion 612b, a first adjusting means 651 is configured to adjust the position of the first substrate 612 with respect to the outer peripheral surface 600a.The first adjustment device 651 is configured to adjust the deviation in a parallel direction between the first substrate 612 and the first frame device 691 and the deviation in the rotation direction. As this configuration, for example, a rotation direction adjustment portion may be provided by the shapes of the protrusion portion 691b and the recess portion 612b, and a plurality of protrusion portions and recess portions may be provided for each first frame device 691.

[0040] Similarly, a recessed portion 622b (second recessed portion) is provided on the detection surface 622a of the second substrate 622. A protrusion portion 692b (second protrusion portion) is provided on the +Z-axis side surface of the second frame member 692. The protrusion portion 692b is inserted into the recessed portion 622b. The protrusion portion 692b and the recessed portion 622b are engaged with each other, and therefore the second substrate 622 and the second frame member 692 are positioned. In this way, a second adjusting means 652 is configured by means of the protrusion portion 692b and the recessed portion 622b, which adjusts the position of the second substrate 622 with respect to the outer peripheral surface 600a.Similar to the first adjusting device 651, the second adjusting device 652 is configured to regulate the deviation in the parallel direction between the second substrate 622 and the second frame device 692 and to regulate the deviation in the rotation direction.

[0041] Next, the assembling process of the encoder 60 configured as described above will be described.

[0042] The Fig. Fig. 4 is a flowchart showing the assembly process of the encoder 60. The assembly of the encoder 60 is carried out according to the processes ST01 to ST06 of Fig. 4 carried out.

[0043] First, a positioning device is positioned on the non-rotating surface 41a of the driver 41 (ST01). In this process, as shown in the Fig. 5, a positioning jig 601 formed in a ring shape such that the dimensions in the radial direction are the same is attached to the drive shaft 42. As the positioning jig 601, a positioning jig is used which is formed such that an outer peripheral surface 601a thereof has the same diameter as an inner peripheral surface 600b of the reference unit 600, and an inner peripheral surface 601b thereof has the same diameter as the outer peripheral surface of the drive shaft 42. Accordingly, the center of the outer peripheral surface 601a of the positioning jig 601 coincides with the axial line C.

[0044] Then, the reference unit 600 is attached to the non-rotating surface 41a of the driver 41 (ST02). In this process, as shown in the Fig. 6, the reference unit 600 is attached to the positioning device 601. Since the diameter of the outer peripheral surface 601a of the positioning device 601 is the same as the diameter of the inner peripheral surface 600b of the reference unit 600, the reference unit 600 is arranged so that there is no gap between the reference unit 600 and the positioning device 601. Accordingly, the center of the reference unit 600 is arranged to coincide with the axial line C. Thereafter, the reference unit 600 is fixed to the non-rotating surface 41a by means of a connecting means (not shown) or the like. After the reference unit 600 is fixed, the positioning device 601 is removed, as shown in FIG. Fig. 7 is shown.

[0045] Then, the first disk 611 is attached to the drive shaft 42 (ST03). During this process, the first disk 611 is fixed to the drive shaft 42 by means of the screw portion 68 and the fastening member 63. Accordingly, the first disk 611 is rotated integrally with the drive shaft 42.

[0046] Next, the first substrate 612 is positioned on the non-rotating surface 41a (ST 04). In this process, first, the first substrate 612 is temporarily fixed by means of the fixing members 612e in a state in which the recessed portion 612b of the first substrate 612 and the protruding portion 691b of the first frame device 691 are engaged with each other. As shown in FIG. Fig. As shown in Fig. 8, each fixing member 612e is inserted into an opening portion 612a formed in advance in the first substrate 612. When the first substrate is temporarily fixed, the inner surface 691a of the first frame member 691 abuts the outer peripheral surface 600a of the reference unit 600 in a state where a positional relationship between the first substrate 612 and the first frame member 691 is maintained, and therefore the first frame member 691 is positioned.

[0047] Further, the position of the opening portion 612h, the position of the recess portion 612b, and the position of the protrusion portion 612b are set in advance so that the positions of the light-reflecting pattern 631 and the magnetic pattern 632, the positions of the light emitting and receiving element 613, and the magnetism detecting element 614 mounted on the first substrate 612 are optimal. Accordingly, the recessed portion 612b and the protruding portion 691b are engaged with each other and are temporarily fixed by means of the fixing members 612e, and the first frame means 691 is positioned, therefore the positions of the light emitting and receiving element 613, the magnetism detecting element 614 with respect to the positions of the light reflecting pattern 631 and the magnetic pattern 632 are positioned to be in an optimal state.In this state, the first substrate 612 and the first frame device 691 are permanently fastened to each other by means of the fastening elements 612e.

[0048] Then, the second disk 621 is mounted on the output shaft 27 (ST05). In this process, the second disk 621 is mounted in a state where the sleeve 64 is mounted on the output shaft 27, and then the second disk 621 is fastened by the nut 65 via the screw portion 67. Accordingly, the second disk 621 is rotated integrally with the output shaft 27.

[0049] Then, the second substrate 622 is positioned on the non-rotating surface 41a (ST06). In this process, first, the second substrate 622 is temporarily fixed by means of the fixing elements 622e in a state in which the recessed portion 622b of the second substrate 622 and the protrusion portion 692b of the second frame means 692 are engaged with each other. The fixing elements 622 are inserted into opening portions 622h formed in advance in the second substrate 622. In this state, each protrusion 692n of the second frame means 692 is inserted between the first frame means 691, as shown in FIG. Fig. 9. Then, the inner surface 692a of each of the second frame members 692 abuts the outer peripheral surface 600a of the reference unit 600, thereby positioning the second frame member 692.

[0050] Furthermore, the position of the recessed portion 622b, the position of the opening portion 622h, and the position of the protruding portion 692b are adjusted in advance so that the position of the light-reflecting pattern 641 is optimal with respect to the light-emitter-receiver element 623 mounted on the second substrate 622. Accordingly, the recessed portion 622b and the protruding portion 692b are engaged with each other and temporarily fixed by means of the fixing members 622e, and the second frame member 692 is positioned, and thereby the positions of the light-emitter-receiver element 623 and the light-reflecting pattern 641 are arranged to be in an optimal state. Then, the second substrate 622 and the second frame member 692 are permanently fixed to each other by means of the fixing members 622e.

[0051] According to the above-described processes, the encoder device 60 is assembled by means of a first fixing process comprising fixing the first disk 611 having the first light-reflecting pattern 631 and the magnetic pattern 632 to the drive shaft 42 rotated about the predetermined axial line C, a first arranging process comprising arranging the first substrate 612 detecting the light-reflecting pattern 631 and the magnetic pattern 632 on the non-rotating surface 41a so as to be positioned by means of the predetermined position reference 600a provided on the reference unit 600.a second fixing process comprising fixing the second disk 621 having the light-reflecting pattern 641 to the output shaft 27, which is rotated about the predetermined axial line and outputs at least a portion of the rotation of the drive shaft 42, and a second arranging process comprising arranging the second substrate 622 detecting the light-reflecting pattern 641 on the non-rotating surface 41a so as to be positioned by means of the position reference 600a. Accordingly, the portion between the first disk 611 and the first substrate 612 and the portion between the second disk 621 and the second substrate 622 can be set to preset positions even when no positioning with signal detection is performed. Therefore, the positioning during assembly can be easily performed. Accordingly, the assembly can be easily performed.

[0052] As described above, the encoder device 60 according to the present embodiment includes the first disk 611 that can be attached to the drive shaft 42, which is rotated about the axial line C, and which has the light-reflecting pattern 631 and the magnetic pattern 632, the first substrate 612 that is positioned on the non-rotating surface 41a and which detects the light-reflecting pattern 631 and the magnetic pattern 632, the second disk 621 that is rotated about the axial line C, which is attached to the output shaft 27, which outputs at least a part of the rotation of the drive shaft 42, and which has the light-reflecting pattern, the second substrate 622 that is positioned on the non-rotating surface 41a and detects the light-reflecting pattern 641, and the reference unit 600 that references the first substrate 612 and the second substrate 622 by means of the common position reference 600a positioned,Therefore, positioning during assembly can be carried out easily. Accordingly, assembly can be carried out easily. [Second embodiment]

[0053] Next, a second embodiment of the present invention will be described. In this embodiment, a case will be described where the encoder device 60 described in the first embodiment is used with a robot device 100 and a drive device 1. Hereinafter, the same reference numerals are assigned to the components corresponding to those of the first embodiment.

[0054] The Fig. Fig. 10 is a perspective view showing a structure of the robot device 100 according to the present embodiment. As shown in Fig. As shown in Figure 10, the robot device 100 includes a first arm 10, a second arm 20, and the drive device 1. The first arm 10 and the second arm 20 are connected to each other by a connecting portion 30. The drive device 1 is provided at the connecting portion 30. The drive device 1 includes a rotation mechanism 40, a torque limiting mechanism 50, the encoder device 60, and a controller 70, and rotates the second arm 20 based on the connecting portion 30.

[0055] The first one at 10 includes a base portion 11 and a bearing 12. The base portion 11 is formed with / in a columnar shape (solid) or a cylindrical shape (hollow) and forms a portion of a structure of the robot device 100. The base portion 11 is fixed to a rotating shaft (not shown) of the robot device 100 and is provided to be rotated in a predetermined direction around the rotating shaft.

[0056] The bearing 12 is provided on an end surface 11a of the base portion 11. For example, the bearing 12 includes a first bearing 12a and a second bearing 12b. The first bearing 12a and the second bearing 12b are arranged so that they are arranged in / along one (e.g., a single) direction (e.g., the Z-axis direction).

[0057] The first bearing 12a is provided directly on the end surface 11a. Furthermore, the second bearing 12b is provided via / next to a reduction gear 43 (e.g., gear / gear) extending from the first bearing 12a to the outside of the end surface 11a.

[0058] The second arm (arm) 20 includes a base portion 21, a bearing 22, and an output shaft 27. Similar to the base portion 11 of the first arm 10, the base portion 21 is formed in a columnar (solid) or cylindrical (hollow) shape and constitutes a portion of a structure of the robot device 100. The bearing 22 is provided on an end surface 21a of the base portion 21. The bearing 22 includes a third bearing 22a and a fourth bearing 22b. The third bearing 22a and the fourth bearing 22b are positioned in a single direction (e.g., the Z-axis direction).

[0059] The third bearing 22a and the fourth bearing 22b are provided directly on the end surface 21a. The third bearing 22a and the fourth bearing 22b of the second arm 20 are positioned with a predetermined distance between them so that a torque limiting mechanism 50 can be installed therebetween.

[0060] The output shaft 27 is a shaft to which torque is transmitted via the rotating mechanism 40 and which is rotated. The output shaft 27 is provided integrally with the third bearing 22a on the +Z-axis side of the third bearing 22a. For example, the output shaft 27 is provided with a columnar shape or a cylindrical shape and is positioned so that the axial line direction is parallel to the Z-axis direction.

[0061] The rotation mechanism 40 is connected to the reduction gear 43 via the second bearing 12b. The rotation mechanism 40 has the driver 41 and the drive shaft 42 ( Fig. 11), rotates the input shaft 42 and drives the second arm 20 by rotating the output shaft 27.

[0062] For example, the encoder described in the first embodiment can be used as the encoder 60. For example, the encoder 60 is connected to the rotary mechanism 40 and detects rotational position information (e.g., angular position) of the output shaft 27 and the drive shaft 42, which are described below. For example, the encoder 60 detects a three-dimensional position and posture of the second arm 20.

[0063] For example, the torque limiting mechanism 50 is positioned at the third bearing 22a and the fourth bearing 22b of the second arm 20. The torque limiting mechanism 50 connects the input shaft 42 and the output shaft 27, so that the torque of the input shaft 42 is transmitted to the output shaft 27, to which the second arm 20 is connected. When a torque equal to or greater than a predetermined allowable torque value is generated between the input shaft 42 and the output shaft 27, the torque limiting mechanism 50 may cause a relative displacement (e.g., slippage) to be generated with respect to the input shaft 42 and the output shaft 27.For example, when a torque equal to or greater than a predetermined allowable torque value is generated between the input shaft 42 and the output shaft 27, the torque limiting mechanism 50 causes the relative displacement between the input shaft 42 and the output shaft 27. For example, as the torque limiting mechanism 50, a torque limiting mechanism (torque limiter) having a known structure, such as a clutch type, flange type, non-contact type, or linear type torque limiter, can be used.

[0064] The control device 70 generally controls the drive device 1, that is, the rotating mechanism 40, the torque limiting mechanism 50 and the encoding device 60.

[0065] Next, the structure of the drive device 1 according to the present embodiment will be described. Fig. 11 and Fig. 12 are block diagrams showing the structure of the drive device 1. In the Fig. 11 and Fig. 12, the same reference numerals are assigned to the same parts as in the Fig. 10, and the description of these parts is omitted.

[0066] As it is in the Fig. 11 and Fig. As shown in Fig. 12, the drive device 1 comprises the rotating mechanism 40, the torque limiting mechanism 50, the encoding device 60 and the control device 70.

[0067] In the present embodiment, for example, one end of the drive shaft 42 is connected to the first encoder 61, and the other end of the drive shaft 42 is connected to the torque limiting mechanism 50 via the reduction gear 43. In addition, the drive shaft 42 is a hollow drive shaft formed with a hollow shape. In addition, in the output shaft 27, which is a portion of the output shaft 27, at least a portion of the output shaft 27 is positioned on the inside of the hollow drive shaft (drive shaft 42), one end of the output shaft 27 is connected to the second arm 20 and the torque limiting mechanism 50, and the other end of the output shaft 27 is connected to the second encoder 62.

[0068] The driver 41 (rotational drive source) of the rotating mechanism 40 rotates the drive shaft 42, which is a hollow drive shaft. Furthermore, the torque generated by the driver 41 is transmitted to the torque limiting mechanism 50 via the reduction gear 43.

[0069] For example, the reduction gear 43 (power transmission section) is a gear that reduces the rotational speed of the input shaft 42 to 1 / 50. The reduction gear 43 reduces the rotational speed of the input shaft 42 and transmits the reduced rotation to the torque limiting mechanism 50 via a transmission shaft 26. In this embodiment, the reduction gear 43 reduces the rotation, for example, such that when the input shaft 42 is rotated 50 times, the transmission shaft 26 and the output shaft 27 are rotated once.

[0070] As described above, the torque limiting mechanism 50 transmits the torque from the input shaft 42 to the output shaft 27 to which the arm 20 is connected, and generates slippage (relative displacement) when a predetermined allowable torque value is generated between the input shaft 42 and the output shaft 27. That is, when the torque equal to or greater than a predetermined allowable value is generated in at least one of the input shaft 42 and the output shaft 27, the torque limiting mechanism 50 generates the relative displacement (e.g., slippage). Further, for example, in the present embodiment, the output shaft 27 is fixed to the second arm 20 by means of bolts 22.

[0071] As it is in the Fig. 12, the first encoder 61 (first detection unit) includes the light emitting and receiving element 613, the magnetism detecting element 614, a first position detecting unit 617 (first detecting unit), and a correction value storing unit 618.

[0072] The light emitter and receiver element 613 detects the pattern formed on the first disc 611 ( Fig. 1) and outputs the first position detection signal, which is a signal indicating the absolute position (rotational position) of the drive shaft 42.

[0073] For example, the magnetism detection element 614 is a Hall element, detects the magnetism of the magnet 615 provided inside the first disk 611, and converts the detected magnetism into electrical signals. Here, the magnetism detection element 614 detects the magnetism of the magnet 615 and outputs a multi-rotation detection signal for detecting the amount of multi-rotation (rotation speed) of the drive shaft 42.

[0074] The correction value storage unit 618 stores a predetermined correction value that corrects the first position information detected by the first encoder 61. The predetermined correction value is changed by the control device 70 with a feedback / feedback control in which slippage is eliminated by the torque limiting mechanism 50 as described below.

[0075] The first position detection unit 617 calculates the first position information indicating the absolute position (rotational position) information of the drive shaft 42 based on the first position detection signal output from the light emitting and receiving element 613 and the multi-rotation detection signal output from the magnetism detection element 614. The first position detection unit 617 outputs the calculated first position information to the controller 70. Further, the first position detection unit 617 corrects the calculated position information based on the predetermined correction value stored in the correction value storage unit 618 when calculating the first position information, and outputs the corrected position information as the first position information.Furthermore, since the first encoder 61 corresponds to the multi-rotation, the first position information is position information corresponding to the multi-rotation. For example, the first position detection unit 617 and the correction value storage unit 618 are provided on / in the first substrate 612 (non-rotating device).

[0076] Furthermore, the second encoder 62, as shown in the Fig. 12, the light emitting and receiving element 623, a second position detecting unit 624 and a correction value storing unit 625.

[0077] The light emitter and receiver element 623 detects the pattern formed on the second disc 621 ( Fig. 1) and outputs the second position detection signal, which is a signal indicating the absolute position (rotational position) of the output shaft 27. The correction value storage unit 625 stores a predetermined correction value in advance that corrects the second position information detected by the second encoder 62.

[0078] The second position detection unit 624 calculates the second position information indicating the absolute position (rotational position) information of the output shaft 27 based on the second position detection signal output by the light emitting and receiving element 623. The second position detection unit 624 outputs the calculated second position information to the controller 70. Further, the second position detection unit 624 performs correction based on the predetermined correction value by storing the calculated position information in the correction value storage unit 625 when calculating the second position information, and outputs the corrected position information as the second position information. For example, the second position detection unit 624 and the correction value storage unit 625 are provided on / in the second substrate 622.

[0079] As described above, the control device 70 generally controls the rotation mechanism 40, the torque limiting mechanism 50, and the encoder device 60. For example, the control device 70 controls the rotation of the rotation mechanism 40 based on a control command supplied from a control device that controls the external robot device 100. In addition, the control device 70 outputs, for example, the detected position information (for example, the first position information, the second position information, or the like) detected by the encoder device 60 to the external control device. As shown in the Fig. As shown in Figure 12, the control device comprises a slip detection unit 71 and a drive control device 72 via 70.

[0080] The slip determination unit 71 determines the presence or absence of slip (relative displacement) generated by the above-described torque limiting mechanism 50 based on the first position information detected by the first encoder 61 and the second position information detected by the second encoder 62. Here, slip is generated by the torque limiting mechanism 50 when a torque equal to or greater than a predetermined allowable value is generated in at least one of the input shaft 42 and the output shaft 27. For example, when an object comes into contact with the second arm 20, slip is generated by the torque limiting mechanism 50.

[0081] Further, the slip determination unit 71 determines the presence or absence of relative displacement based on estimated position information of the output shaft 27 estimated from the first position information detected by the first encoder 61 and the second position information detected by the second encoder 62. For example, the slip determination unit 71 compares the estimated position information of the output shaft 27 estimated from the first position information and the second position information detected by the second encoder 62. If a difference between the two position information is equal to or greater than a predetermined threshold, the slip determination unit determines that slippage is being generated by the torque limiting mechanism 50.The slip determination unit 71 outputs the determined result of whether relative displacement (e.g., slip) from the torque limiting mechanism 50 was present or not present to the drive control device 72.

[0082] The drive control unit 72 executes control of the rotating mechanism 40 based on the control command supplied from the external control device and the first position information or the second position information detected by the encoder 60. Further, when the slip detection unit 71 determines that slip (relative displacement) is generated by the torque limiting mechanism 50, the drive control unit 72 executes process control that controls the rotation of the drive shaft 42 by the rotating mechanism 40 and feedback control that eliminates the slip by the torque limiting mechanism 50. The drive control unit 72 further includes a rotation control unit 73.

[0083] The rotation control device 73 includes a drive circuit (not shown) that drives the driver 41. The rotation control device 73 controls the rotation of the driver 41 of the rotation mechanism 40 based on the control command supplied from the external control device and the first position information or the second position information detected by the encoder 60. The rotation control device 73 controls the position and posture of the second arm 20 by controlling the rotation mechanism 40.

[0084] In addition, when the slip detection unit 71 detects that slip (relative displacement) is generated by the torque limiting mechanism 50, the rotation controller 73 executes process control that controls the rotation of the drive shaft 42 via the rotation mechanism 40. For example, the process control is an operation that stops the rotation of the drive shaft 42 with respect to the rotation mechanism 40. That is, when an object comes into contact with or collides with the second arm 20, the rotation controller 73 executes control that stops the operation / operation so that the object or the robot device 100 is not damaged.

[0085] Furthermore, the process controller includes feedback control (offset feedback control) that eliminates the slippage from the torque limiting mechanism 50. For example, when the slippage detection unit 71 detects that slippage (relative offset) is generated by the torque limiting mechanism 50, the rotation controller 73 executes feedback control (offset feedback control) that eliminates a positional deviation between the first encoder 61 and the second encoder 62 generated by the slippage of the torque limiting mechanism 50.

[0086] As an example of the feedback control, the rotation control device 73 performs control that changes a predetermined correction value stored in the correction value storage unit 618 so that the first position information detected by the first encoder 61 coincides with the estimated position information of the drive shaft 42 estimated from the second position information from the second encoder 62. The rotation control device 73 changes an offset value used by the first encoder 61 for the correction so that the first position information and the second position information coincide. Accordingly, the rotation control device 73 eliminates the position deviation generated by the slip of the torque limiting device 50.

[0087] Next, the operation of the drive device 1 and the robot device 100 will be described. When the drive device 1 and the robot device 100 are operated, the rotation control device 73 of the control device 70 controls the rotation of the driver 41 of the rotation mechanism 40 based on the control command supplied from the external control device and the first position information or the second position information detected by the encoder 60, and rotates the drive shaft 42.

[0088] The rotation control device 73 operates the driver 41 of the rotating mechanism 40. According to this operation, the rotation of the driver 41 is reduced by the reduction gear 43 and transmitted to the torque limiting mechanism 50 via the transmission shaft 26. The rotation is transmitted to the output shaft 27 within a range not exceeding the allowable value of the torque limiting mechanism 50, and the output shaft 27 is rotated in the circumferential direction of the outer peripheral surface. In this way, the torque of the drive shaft 42 is transmitted to the output shaft 27. Accordingly, the second arm 20 is driven.

[0089] Next, an operation will be described in which the drive device 1 detects the slip (relative displacement) generated between the drive shaft 42 and the output shaft 27 by the torque limiting mechanism 50. For example, when an object comes into contact with or collides with the second arm 20, and a torque equal to or greater than the allowable torque value predetermined in the torque limiting mechanism 50 is applied between the drive shaft 42 and the output shaft 27, the slip is generated between the drive shaft 42 and the output shaft 27 in the torque limiting mechanism 50.

[0090] The Fig. 13 is a view showing an example of slip detection of the drive device 1 in the present embodiment.

[0091] In the Fig. 13, a left vertical axis of the graph indicates position information Pi (first position information) of the first encoder 61, and a right vertical axis indicates position information Po (second position information) of the second encoder 62. Further, a horizontal axis of the graph indicates time t.

[0092] Further, a curve W1 indicates the offset of the first position information Pi detected by the first encoder 61, and a curve W2 indicates the offset of the second position information Po detected by the second encoder 62. Here, the second position information Po satisfies the relationship (Po=Pi / n) due to a reduction ratio n of the reduction gear 43. Further, in the present embodiment, as an example, the reduction ratio n of the reduction gear 43 is "50" (n=50).

[0093] The Fig.13 shows an example where an object comes into contact with or collides with the second arm 20 at time t1, and the torque equal to or greater than the predetermined allowable torque value occurs in the torque limiting mechanism 50 between the input shaft 42 and the output shaft 27. As shown by the curve W2, since the second arm 20 comes into contact with the object at time t1, the second position information Po, which is the position information of the output shaft 27, is not changed. Meanwhile, as shown by the curve W1, the first position information Pi, which is the position information of the input shaft 42, is continuously changed similarly to the state before the contact or collision because the slip is generated by the torque limiting mechanism 50.

[0094] The slip determination unit 71 determines the presence or absence of slip (relative displacement) of the above-described torque limiting mechanism 50 based on the first position information detected by the first encoder 61 and the second position information detected by the second encoder 62. For example, the slip determination unit 71 compares the estimated position information (Pi / n) of the output shaft 27 estimated from the first position information Pi detected by the first encoder 61 and the second position information Po detected by the second encoder 62.If the difference between the second position information Po and the estimated position information (Pi / n) of the output shaft 27 is equal to or greater than the predetermined threshold value, the slip determination unit 71 determines that the slip is being generated by the torque limiting mechanism 50 (see time t2). Furthermore, the slip determination unit 71 transmits the determined results to the rotation control device 73 of the drive control device 72.

[0095] Further, at time t2, the slip detection unit 71 detects that the slip (relative displacement) is generated by the torque limiting mechanism 50, and the rotation controller 73 executes process control that controls the rotation of the drive shaft 42 in the rotation mechanism 40 by feeding back the detected results based on the detected results. Here, for example, the rotation controller 73 performs, as process control, an operation that stops the rotation of the drive shaft 42 with respect to the rotation mechanism 40. That is, when an object comes into contact with or collides with the second arm 20, the rotation controller 73 executes control that stops the operation of the second arm 20 so that the object or the robot device 100 is not damaged.

[0096] Furthermore, the rotation controller 73 executes feedback control (offset feedback control) that eliminates the slippage due to the torque limiting mechanism 50 as process control. That is, at time t2, the rotation controller 73 executes feedback control (offset feedback control) that eliminates the positional deviation generated by the slippage of the torque limiting mechanism 50 between the first encoder 61 and the second encoder 62. For example, as feedback control, the rotation control means 73 performs control that changes a predetermined correction value stored in the correction value storage unit 618 so that the first position information Pi detected by the first encoder 61 agrees with the estimated position information (Pi*n) of the drive shaft 42 estimated from the second position information of the encoder 62.First, the rotation control unit 73 calculates a slip amount ΔP (=Pi-n*Po) based on the estimated position information (n*Po) of the drive shaft 42 and the first position information Pi. The rotation control unit 73 stores the calculated slip amount ΔP in the correction value storage unit 618 as a predetermined correction value.

[0097] Accordingly, the slip between the input shaft 42 and the output shaft 27 is eliminated, and a relative positional relationship between the input shaft 42 and the output shaft 27 is restored (see time t3).

[0098] As described above, in the drive device 1 in the present embodiment, the rotation mechanism 40 rotates the input shaft, the first encoder 61 detects the first position information indicating the rotational position of the input shaft 42, and the second encoder 62 detects the second position information indicating the rotational position of the output shaft 27. In addition, the torque limiting mechanism 50 can generate the relative displacement (slip) with respect to the input shaft 42 and the output shaft 27. In addition, the controller 70 (slip determination unit 71) determines the presence or absence of the relative displacement (slip) based on the first position information detected by the first encoder 61 and the second position information detected by the second encoder 62.

[0099] Accordingly, the drive device 1 can appropriately detect that a driven body (for example, the second arm 20) comes into contact with the object. In the drive device 1 according to the present embodiment, it is possible to reduce damage to the contacted object or the robot device 100 due to contact between the driven body (for example, the second arm 20) and the object.

[0100] Furthermore, in the present embodiment, when the relative displacement (slip) is generated, the controller 70 (rotation controller 73) performs process control that performs fully closed-loop control on the rotation of the drive shaft 42 by means of the rotation mechanism 40. Accordingly, the rotation mechanism 40 is appropriately controlled when the driven body (for example, the second arm 20) comes into contact with the object. Therefore, in the drive device 1 in the present embodiment, it is possible to reduce damage to the contacted object or the robot device 100 as a result of the contact between the driven body (for example, the second arm 20) and the object.

[0101] Furthermore, in the present embodiment, the process controller includes feedback control (displacement feedback control) that eliminates the relative displacement (slip). This allows the drive device 1 in the present embodiment to perform fully closed-loop control, which resumes (returns) the operation of the robot device 100, after the drive device 1 detects that the driven body (for example, the second arm 20) comes into contact with the object.

[0102] Furthermore, in the present embodiment, the first encoder 61 outputs the position information, in which the detected position information is corrected based on a predetermined correction value, as first position information. The controller 70 (rotation controller 73) executes, as feedback control (offset feedback control), control that changes a predetermined correction value so that the first position information corresponds to the estimated position information of the drive shaft 42 estimated from the second position information. Accordingly, the relative offset (slip) can be eliminated by changing the predetermined correction value. In this case, control that reversely rotates the rotation mechanism 40 or the like is not necessary to eliminate the relative offset (slip).Accordingly, in the drive device 1 of the present embodiment, a time until the operation of the robot device 100 is resumed can be reduced.

[0103] Furthermore, in the present embodiment, the control device 70 (slippage determination unit 71) determines the presence or absence of the relative displacement (slip) based on the estimated position information of the output shaft 27, which is estimated from the first position information, and the second position information. Accordingly, in the drive device 1 of the present embodiment, the slippage (relative displacement) between the input shaft 42 and the output shaft 27 can be accurately determined by a simple determination means using the first encoder 61 and the second encoder 62.

[0104] Additionally, in the present embodiment, one end of the drive shaft 42 is connected to the first encoder 61, and the other end of the drive shaft 42 is connected to the torque limiting mechanism 50 via the reduction gear 43 (power transmission section). Further, the drive shaft 42 is a hollow drive shaft formed in a hollow shape. At least a portion of the output shaft 27 is positioned on the inside of the hollow drive shaft (drive shaft 42), with one end of the output shaft 27 being connected to the driven body (for example, the second arm 20) and the torque limiting mechanism 50, and the other end of the output shaft 27 being connected to the second encoder 62.Accordingly, since the first encoder 61 and the second encoder 62 can be positioned on the side of the drive shaft 42 where the rotary mechanism 40 is positioned, the first encoder 61 and the second encoder 62 and the rotary mechanism 40 can be integrally constructed or structured. This allows a reduction in size in the drive device 1.

[0105] Furthermore, since the second encoder 62 is positioned on the side opposite the driver 41, it is unnecessary to consider erroneous detection of the second encoder 62 due to oil, dirt, or the like to which the driver 41 is exposed. For example, if the second encoder 62 is positioned on the side opposite the driver 1 (the same side as the first encoder 61) by means of the hollow drive shaft, similar to the first encoder 61, the second encoder 62 can be housed in the arm or drive device and can be in the integral structure. Since the inner portion of the arm or drive device is configured to be separated from the external oil or dirt by means of a seal or the like, it is unnecessary to consider erroneous detection of the second encoder 62 due to oil, dirt, or the like.Accordingly, in the drive device 1 of the present embodiment, a light detector type encoder can be used for the second encoder 62. The drive device 1 of the present embodiment can detect the position information of the output shaft 27 with high accuracy.

[0106] Furthermore, in the present embodiment, the robot device 100 includes the drive device 1. Accordingly, the robot device 100 of the present embodiment can appropriately detect that the driven body (for example, the second arm 20) comes into contact with the object. Therefore, in the robot device 100 in the present embodiment, it is possible to reduce the damage to the contacted object or the robot device 100 that occurs as a result of the contact between the driven body (for example, the second arm 20) and the object.

[0107] Furthermore, in the present embodiment, the drive device 1 includes the first encoder 61 and the second encoder 62. Since the position information of the input shaft 42 and the position information of the output shaft 27 can be correctly detected by two encoders, the drive device 1 of the present embodiment can correctly detect not only the slippage of the torque limiting mechanism 50, but also vibration, inclination / unevenness, speed deviation, or the like of the output shaft 27.

[0108] The technical scope of the present invention is not limited to the above-described embodiment and can be appropriately changed within a scope that does not deviate from the spirit of the present invention.

[0109] For example, in the above-described embodiment, the structure in which the outer peripheral surface 600a of the reference unit 600 is set to the position reference / reference position is described as an example. However, the present invention is not limited thereto. For example, the present invention may include a structure in which the inner peripheral surface 600b of the reference unit 600 is set to the reference position.

[0110] Further, when the outer peripheral surface 600a and the inner peripheral surface 600b are cylindrical surfaces centered on the axial line C, the present invention may, for example, have a configuration in which one of the first frame member 691 and the second frame member 692 is adjacent to and positioned on the outer peripheral surface 600a of the reference unit 600, and the other is adjacent to and positioned on the inner peripheral surface 600b. In this case, the position reference becomes the axial line C.

[0111] Furthermore, in the above-described embodiment, the aspect is described in which the control device 70 (slippage determination unit 71) determines the presence or absence of the relative displacement (slippage) based on the estimated position information of the output shaft 27 estimated from the first position information and the second position information. However, the present invention is not limited to this. For example, the invention may have an aspect in which the control device 70 (slippage determination unit 71) determines the presence or absence of the relative displacement (slippage) based on the estimated position information of the input shaft 42 estimated from the second position information and the first position information.Accordingly, the drive device 1 can correctly detect the slip (relative displacement) between the input shaft 42 and the output shaft 27 by the simple detecting means using the first encoder 61 and the second encoder 62.

[0112] Furthermore, the present invention may have an aspect in which the control device 70 (slippage determination unit 71) determines the presence or absence of the relative displacement (slippage) by combining the determination method using the estimated position information of the input shaft 42 estimated from the above-described second position information and the determination method using the estimated position information of the output shaft 27 estimated from the first position information.

[0113] Furthermore, in the above-described embodiment, the aspect is described in which the control device 70 (slippage determination unit 71) determines the presence or absence of relative displacement (slippage) using the slippage amount ΔP (=Pi-n*Po) calculated based on the first position information Pi and the second position information Po. However, the present invention may have an aspect in which the presence or absence of the relative displacement (slippage) is determined based on the calculated results, such as a ratio / quotient between the first position information Pi and the second position information Po.

[0114] In addition, in the present embodiment, the aspect is described in which the control means 70 (rotation control means 73) executes the control that changes the predetermined correction value so that the first position information agrees with the estimated position information of the input shaft estimated from the second position information as the feedback control (displacement feedback control). However, the present invention is not limited to this. For example, the present invention may have an aspect in which the control means 70 (rotation control means 73) executes the control that changes a predetermined correction value of the second encoder 62 so that the second position information agrees with the estimated position information of the output shaft 27 estimated from the first position information as the feedback control.

[0115] Furthermore, in the above-described embodiment, a structure in which at least a portion of the torque limiting mechanism 50 is connected to the second arm 20 is described as an example. However, the present invention is not limited thereto. For example, the present invention may have an aspect in which the torque limiting mechanism 50 is connected to an external connecting portion and is provided to be independent of the second arm 20.

[0116] Furthermore, in the above-described embodiment, the aspect in which the drive shaft 42 is connected to the torque limiting mechanism 50 via the reduction gear 43 is described. However, the present invention may have an aspect in which the reduction gear 43 is not provided. Further, the present invention may have an aspect in which the first encoder 61 is connected to the drive shaft 42, in which the rotational speed is reduced via the reduction gear 43, and in which the rotational position information at which the rotational speed is reduced via the reduction gear 43 is detected.

[0117] Furthermore, in the above-described embodiment, a case is described where the first encoder 61 and the second encoder 62 are optical encoders using light emitting and receiving elements (613 and 623). However, the present invention may have an aspect that includes other types (for example, a magnetic type or the like) of encoders.

[0118] Furthermore, in the above-described embodiment, the aspect in which the first position detecting unit 617 and the correction value storing unit 618 are provided on the first substrate 612 is described. However, the present invention may have an aspect in which the first position detecting unit 617 and the correction value storing unit 618 are provided on the outside, similar to the controller 70. Furthermore, the present invention may have an aspect in which the controller 70 is provided on the first substrate 612 together with the first position detecting unit 617 and the correction value storing unit 618.

[0119] Furthermore, in the above-described embodiment, the aspect in which the second position detecting unit 624 and the correction value storing unit 625 are provided on the second substrate 622 is described. However, the present invention may have an aspect in which the second position detecting unit 624 and the correction value storing unit 625 are provided on the outside, similar to the controller 70. Furthermore, the present invention may have an aspect in which the controller 70 is provided together with the second position detecting unit 624 and the correction value storing unit 625 on the second substrate 622.

[0120] A computer system is provided in the internal portion of the above-described control device 70. Furthermore, the control process of the above-described control device 70 is stored in a computer-readable storage medium according to a program type, and control is performed by reading and executing the program using the computer. Here, the computer-readable storage medium includes a magnetic floppy disk, a magneto-optical floppy disk, a CD-ROM, a DVD-ROM, a semiconductor memory, or the like. Furthermore, the computer program is transmitted to the computer via a communication line, and the computer receiving the transmission can execute the program.

[0121] Furthermore, in a robot or machine tool (hereinafter referred to as a robot device) having an arm, a narrow width and a reduction in the size of the arm, if possible, are necessary because a tip side of the arm is placed in a narrow area due to an operating characteristic of the robot device. For example, when an additional part such as an output-side encoder (for example, the second encoder) is mounted, the additional part should generally be mounted on the output side / driven side because the additional part is the output-side encoder, and the output side of the arm of the robot device is the tip side, therefore, it is necessary that the output-side encoder be mounted on the arm on the tip side. Accordingly, an increase in the volume of the tip-side arm cannot be avoided, and a reduction in its size cannot be achieved.However, in the present embodiment, since the second encoder 62 can be positioned on the base-side arm that is on the same side as the first encoder 61 due to the use of the hollow drive shaft formed in / with a hollow shape (the detection unit of the second encoder 62 is fixed to the base-side arm and is not rotated together with the tip-side arm), the second encoder 62 is not mounted on the tip-side arm, and therefore a double encoder configuration can be achieved in which a reduction in the volume of the tip-side arm is achieved.

[0122] Furthermore, since the output-side encoder is generally mounted on the outside of the tip-side arm so that it is not rotated together with the tip-side arm to detect the rotation angle of the output side while mounted on the tip-side arm, the detection unit of the output-side encoder is exposed to the outside environment. Considering that the environment of the robot device is not always free of dust or oil, the detection unit of the output-side encoder is likely to become contaminated. However, according to the structure of the present embodiment, the output-side encoder can be mounted on the base-side arm similarly to the input-side encoder. Here, the base-side arm on which the input-side encoder is mounted serves as the base of the joints thereof, and therefore the base-side arm is not rotated.Accordingly, the output-side encoder is housed in the inner portion of the arm, similar to the input-side encoder, so the detection unit can be protected from environmental dirt or oil. Therefore, the output-side encoder of the present invention, similar to the input-side encoder, is not easily contaminated, thus increasing its resistance to contamination and the like. Description of reference symbols

[0123] 1: drive device, 20: second arm, 27: output shaft, 41: driver, 41a: non-rotating surface, 42: drive shaft, 42a: hollow section, 50: torque limiting mechanism, 60: encoder, 61: first encoder, 62: second encoder, 70: control device, 100: robot device, 600: position reference unit, 600a: outer peripheral surface (position reference), 601: positioning device, 601a: outer peripheral surface, 601b: inner peripheral surface, 611: first disk, 612: first substrate, 612b: recessed section, 616: rear yoke, 621: second disk, 622: second substrate, 622b: recessed section, 631: light-reflecting pattern, 632: magnetic pattern, 641: light-reflecting pattern, 651: first adjusting device, 652: second adjusting device, 691: first frame device, 692: second frame device, C: axial line

Claims

[1] A drive device (1) comprising a driver (41), a rotary shaft (42) rotatable about a predetermined axial line (C) by being driven by the driver (41), an output shaft (27) which is rotatable about the predetermined axial line (C) and which can output at least part of the rotation of the rotary shaft (42), and an encoding device (60) configured to detect rotation information of the rotary shaft (42) and the output shaft (27), the encoding device (60) comprising: a first encoder (61) comprising: a first rotating device (611) which is attached to the rotating shaft (42) and which has a first pattern (631), a first substrate (612) supported by a first frame means (691), wherein the first frame means (691) is supported by a non-rotating surface (41a) of the driver (41), wherein a portion of the housing of the driver (41) has the non-rotating surface (41a), and the non-rotating surface (41a) is formed in a circular shape when viewed in the axial direction, wherein the first substrate (612) has a detection surface (612a) facing the first rotating device (611), and wherein a through-hole (612f) is formed in a central portion of the first substrate (612) and the output shaft (27) extends in the axial direction through the through-hole (612f), a light emitting and receiving element (613) and a magnetism detecting element (614) installed on the first substrate (612), wherein the light emitting and receiving element (613) and the magnetism detecting element (614) are provided on the detecting surface (612a) of the first substrate (612), a first detector unit (617) positioned on a non-rotating device and arranged to detect the first pattern (631), a second encoder (62) comprising: a second rotating device (621) which is attached to the output shaft (27) and which has a second pattern (641), a second substrate (622) supported by a second frame means (692), wherein the second frame means (692) is supported by the non-rotating surface (41a) of the driver (41), wherein the second substrate (622) has a detection surface (622a) directed towards the second rotating device (621), a light emitting and receiving element (623) installed on the second substrate (622), wherein the light emitting and receiving element (623) is provided on the detection surface (622a) of the second substrate (622), a second detector unit (624) positioned on the non-rotating device and configured to detect the second pattern (641), and a reference unit (600) which is attached to the non-rotating surface (41a) of the driver (41) and which has a common position reference (600a), wherein the reference unit (600) is formed in a ring shape, wherein the common position reference (600a) is provided on a cylindrical surface whose center forms the predetermined axial line (C) and which is an outer peripheral surface (600a) of the reference unit (600), wherein an inner surface (691a) of the first frame means (691) faces and adjoins the outer peripheral surface of the reference unit (600) and an inner surface (692a) of the second frame means (692) faces and adjoins the outer peripheral surface of the reference unit (600), so that the reference unit (600) positions the first detector unit (617) and the second detector unit (624) by means of the common position reference (600a), wherein the inner surface (691a) of the first frame means (691) has the same diameter as the outer peripheral surface (600a), and wherein the inner surface (692a) of the second frame means (692) has the same diameter as the outer peripheral surface (600a). [2] The drive device (1) according to claim 1, wherein a first shaft, which is either the rotary shaft (42) or the output shaft (27), has a hollow portion (42a), wherein a second shaft, which is the other of the rotary shaft (42) and the output shaft (27) and is different from the first shaft and is arranged to protrude into the hollow portion (42a), is provided so as to protrude from one end of the first shaft, wherein the first rotating means (611) is provided at one end of the first shaft, and wherein the second rotating means (621) is provided at a portion of the second shaft protruding from the first shaft. [3] The drive device (1) according to one of claims 1 to 2, further comprising: a first adjusting device (651) configured to adjust an abutment position between the first detector unit (617) and the reference unit (600) adjacent to the first detector unit (617). [4] The drive device (1) according to claim 3, wherein the first adjusting device (615) comprises a first recess portion (612b) provided at one of the reference unit (600) and the first detector unit (617), and a first projection portion (691b) provided on the other of the reference unit (600) and the first detector unit (617), and fitted into the first recess portion (612b). [5] The drive device (1) according to one of claims 1 to 4, further comprising: a second adjusting device (652) configured to adjust an abutment position between the second detector unit (624) and the reference unit (600) adjacent to the second detector unit (624). [6] The drive device (1) according to claim 5, wherein the second adjusting device (652) comprises a second recess portion (622b) provided at one of the reference unit (600) and the second detector unit (624), and a second projection portion (692b) provided on the other of the reference unit (600) and the second detector unit (624), and fitted into the second recess portion (622b). [7] The drive device (1) according to one of claims 1 to 6, wherein the non-rotating device comprises a magnetic field generator (615), and wherein the encoding device (60) comprises a yoke (616) configured to shield a magnetic field to the first pattern (631) and the second pattern (632) from the driver (41). [8] The drive device (1) according to any one of claims 1 to 7, wherein the output shaft (27) is independently supported by means of a bearing (66) between the output shaft (27) and the rotary shaft (42). [9] The drive device (1) according to any one of claims 1 to 8, further comprising a connecting portion configured to connect the rotary shaft (42) and the output shaft (27) and to displace the rotary shaft (42) and the output shaft (27) relative to each other when the torque transmitted from the rotary shaft (42) to the output shaft (27) exceeds a predetermined value. [10] A robot device (100) comprising one arm (20) and a drive device (1) adapted to drive the arm (20), wherein the drive device (1) according to one of claims 1 to 9 is used as the drive device (1).

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