JP2017151072A - Actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an actuator capable of preventing the non-uniform contact of a strain element from occurring while improving the detection accuracy.SOLUTION: An actuator 1 includes: a first rotor 11 rotatable around an input shaft 15 and having a first groove part 21 extending in a first direction; a second rotor 12 having a second protrusion part 31 rotatable around the output shaft and extending in a second direction substantially orthogonal to the first direction; a first bearing for supporting the first rotor 11 to a housing; a second bearing for supporting a second rotor 12 to the housing; a first protrusion part 22 engageable via an interval in a direction vertical to the first grove part 21 and the input shaft; and a second groove part 32 engageable with the second protrusion part 31 via the interval in the direction vertical to an output shaft. The actuator 1 further includes: a strain element 13 for transmitting a rotational torque of the input shaft to the output shaft; and a detection element 14 mounted on the strain element 13 and measuring a strain of the strain element 13 due to a rotation torque.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an actuator having a torque sensor.

  Generally, a torque sensor is applied to an actuator that controls a rotational drive system. The torque sensor is attached to a rotating body supported by a bearing, and has a strain generating portion that generates distortion due to a torsional moment. The torque of the rotating body is detected by measuring the distortion of the strain generating portion. In order to realize highly accurate control, accurate measurement of torque is required, and various techniques have been developed.

  Patent Document 1 has a split structure of a first rotating body (inner ring) and a second rotating body (outer ring) formed of a pair of concentric circular bodies having different diameters, and a strain generating body. A torque sensor is disclosed that transmits torque from an inner ring to an outer ring via a ring. The strain body is a shaft (beam) that is formed integrally with the inner ring and protrudes from the outer periphery of the inner ring toward the inner periphery of the outer ring.

  The strain body is movable relative to the outer ring in the axial direction, radial direction, and rotational direction, and has an engaging portion that can be engaged in the rotational direction. This torque sensor has a predetermined degree of freedom in the above three directions, thereby reducing the influence of vibration generated in the rotating body and enabling highly accurate torque detection.

  Patent Document 2 discloses a torque sensor that measures torque transmitted from a primary side fastening member (input side) to a secondary side fastening member (output side). The torque sensor includes a first structure coupled to the primary-side fastening member, a second structure coupled to the secondary-side fastening member, and a strain generating unit that couples the first structure and the second structure. And a strain sensor capable of detecting the deformation amount of the strain generating portion. The first structure is coupled to the primary side fastening member by bolt joining. The first structure and the primary side fastening member have a play smaller than the play of the bolt joint in the torque acting direction (circumferential direction) as the direction in which the torque acts by the combination of the projecting part and the groove part that accommodates the projecting part. Are mating with each other.

  Patent Document 3 discloses a torque sensor in which a load member that receives a load and a torque member that receives torque are independently configured. The torque member cross-section secondary moment is maximized in the rotation direction (minimum in the axial direction), and the load member cross-section secondary moment is maximized in the axial direction (minimum in the rotation direction). Thus, highly accurate torque detection can be performed while preventing the load received by the load member from affecting the torque member.

JP 2011-209099 A JP 2013-061305 A JP 2007-040774 A

  In Patent Document 1, in the torque sensor built in the actuator, the engaging portions of the four strain-generating bodies are separated from the engaging recesses of the outer ring via a predetermined gap. As a result, transmission of force / torque in directions other than the torque around the axis to be detected is interrupted, and detection accuracy is improved. However, there is a limit to the processing accuracy of the engagement recess of the outer ring, the processing accuracy of the width of the engaging portion of the strain generating body, and the processing accuracy of the gap between the engaging recess and the engaging portion to be engaged.

  If the widths of the gaps are not uniform, the four engaging portions do not evenly hit the respective engaging recesses and transmit torque, but only one place is hit depending on the magnitude of the torque. It is conceivable that a place will be hit. In this case, the deformation states of the four strain generating bodies are all different, the bridge balance of the resistance of the detection element for detecting the torque is lost, and it is very difficult to improve the torque detection accuracy.

  In addition, the strain body is supported by the housing by the first and second bearings via the rotation transmitting member and the speed reducer, and the outer ring is supported by the housing via different bearings. As described above, the strain generating body and the outer ring are supported by the housing by different bearings, and the shaft center of the bearing may be displaced. When the rotational axes of the input side (reduction gear and inner ring) and the output side (outer ring and output shaft) of the torque sensor are shifted, the widths of the gaps between the engaging portion and the engaging recess are equalized. There is a risk that only one part of the four engaging parts hits the corresponding engaging concave part, and one-sided contact may occur. For this reason, a uniform rotational torque is not applied to the strain generating body (a uniform strain does not occur in the strain generating body), and the torque detection accuracy is deteriorated.

  The present invention has been made against the background of the above problems, and an object of the present invention is to provide a technique capable of suppressing the contact of the strain generating element and improving the detection accuracy. is there.

  The actuator according to the embodiment includes a first rotating body having a first engaging portion extending in a first direction and rotatable around an input shaft, and the first direction rotatable around an output shaft. A second rotating body having a second engaging portion extending in a second direction substantially orthogonal to the first rotating body, a first bearing that supports the first rotating body with respect to the housing, and the first bearing with respect to the housing. A second bearing that supports the two-rotor, a first engagement receiving portion that can be engaged with the first engagement portion through a gap perpendicular to the input shaft, the second engagement portion, and the A second engagement receiving portion that is engageable via a gap in a direction perpendicular to the output shaft, and a strain generating body that transmits the rotational torque of the input shaft to the output shaft, and is attached to the strain generating body. And a detection element for measuring the strain of the strain generating body due to the rotational torque.

In the actuator described above,
At least a portion of the side surface of the first engagement portion and the side surface of the first engagement receiving portion facing each other around the input shaft are in surface contact with each other,
At least a part of the side surface of the second engagement portion and the side surface of the second engagement receiving portion facing each other around the output shaft may be in surface contact.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the actuator which can suppress the contact | abutting of the strain body and can improve detection accuracy.

FIG. 3 is a cross-sectional view showing the configuration of the actuator according to the first embodiment. 1 is a perspective view illustrating a configuration of a torque sensor according to a first embodiment. 3 is a diagram illustrating a configuration of a strain generating body according to Embodiment 1. FIG. It is IV-IV sectional drawing of FIG. It is VV sectional drawing of FIG. FIG. 5 is a cross-sectional view showing an engagement relationship between the first groove portion of the first rotating body and the first projecting portion of the strain generating body in the first embodiment. It is a figure explaining the torque sensor of a comparative example. It is a figure explaining the torque sensor of a comparative example. It is a figure explaining the torque sensor of a comparative example. It is a figure explaining the torque sensor of a comparative example. 6 is a perspective view showing a configuration of a torque sensor according to Embodiment 2. FIG. FIG. 9 is a cross-sectional view showing an engagement relationship between a first groove portion of a first rotating body and a first projecting portion of a strain generating body in Embodiment 2.

<Embodiment 1>
The first embodiment will be described below with reference to the drawings. In the following drawings, components having the same action are denoted by the same reference numerals. In addition, the dimensional relationship in each figure does not reflect the actual dimensional relationship. For the sake of explanation, in each figure, three axes (x axis, y axis, z axis) that are orthogonal to each other are shown as appropriate.

  The present embodiment relates to an actuator having a built-in torque sensor that is incorporated in a joint portion such as a hand, foot, or neck of an articulated robot and drives the robot. As the configuration of the robot, any configuration can be applied as long as a predetermined work can be performed.

  FIG. 1 is a cross-sectional view showing the configuration of the actuator according to the present embodiment. As shown in FIG. 1, the actuator 1 includes a housing 2, an encoder 3, a rotor 4, a stator 5, a speed reducer 6, a first bearing 7, a second bearing 8, and a torque sensor 10. The encoder 3, the rotor 4, the stator 5, the speed reducer 6, the first bearing 7, the second bearing 8, and the torque sensor 10 are accommodated in the housing 2.

  The rotor 4 and the stator 5 constitute an electric motor. As the motor having the rotor 4 and the stator 5, a general three-phase AC synchronous motor (DC brushless motor) can be used. The motor is controlled according to a control signal supplied from a control unit (not shown). The rotor 4 is fixed to a motor shaft (drive shaft) extending in the x-axis direction within the housing 2 and rotates integrally. The stator 5 includes a core, a coil, and the like that are disposed to face the rotor 4, and is attached to the inside of the housing 2. The stator 5 generates a rotating magnetic field and rotationally drives the rotor 4.

  The encoder 3 is connected to the motor shaft of the motor. The encoder 3 detects the rotation angle of the motor and supplies the encoder information to a control unit (not shown).

  The torque sensor 10 detects the rotational torque generated when the rotational driving force is transmitted to the output shaft, and supplies the detected information to a control unit (not shown). The motor is controlled using the encoder information and the detection information of the torque sensor 10. The torque sensor 10 will be described in detail later.

  The speed reducer 6 is connected to the motor shaft of the motor. The speed reducer 6 decelerates the rotational speed input from the motor shaft by a predetermined reduction ratio, and generates a rotational driving force having a predetermined rotational torque. As the speed reducer 6, various types of speed reducers can be applied. For example, a wave gear speed reducer is used.

  FIG. 2 is a perspective view showing a configuration of the torque sensor 10 of FIG. As shown in FIG. 2, the torque sensor 10 includes a first rotating body 11, a second rotating body 12, a strain generating body 13, a detection element 14 (FIG. 3), an input shaft 15, and an output shaft 16. In FIG. 2, the configuration of the strain generating body 13 is illustrated in a simplified manner. In FIG. 2, only the 1st protrusion part 22 and the 2nd groove part 32 of the strain body 13 are shown. FIG. 3 is a diagram showing the configuration of the strain body 13 in detail. 4 is a sectional view taken along line IV-IV in FIG. 3, and FIG. 5 is a sectional view taken along line VV in FIG. FIG. 6 is a cross-sectional view illustrating an engagement relationship between the first groove portion of the first rotating body and the first projecting portion of the strain generating body. 2, 4, and 5 show a state in which the strain generating body 13, the first rotating body 11, and the second rotating body 12 are not engaged for the sake of explanation.

  The input shaft 15 of the torque sensor 10 is formed coaxially with the speed reducer output shaft 9, and is fastened by a screw or the like (not shown), whereby the first rotating body 11 is fixed to the speed reducer output shaft 9. The first rotating body 11 rotates with the input shaft 15 using the reduction gear output shaft 9 as an input shaft 15. The output shaft 16 is formed coaxially with the input shaft 15. The input shaft 15 and the output shaft 16 are the rotation shafts of the torque sensor 10.

  The first rotating body 11 is a disk-shaped member. The upper surface and the lower surface of the first rotating body 11 are arranged in a direction perpendicular to the x axis, that is, a direction parallel to the yz plane. An input shaft 15 is connected to one surface of the first rotating body 11. On the other surface of the first rotating body 11, a first groove portion 21 that serves as a “first engaging portion” is provided. The 1st groove part 21 is formed along the direction orthogonal to the rotating shaft of a torque sensor. The shape of the cross section orthogonal to the longitudinal direction of the first groove portion 21 is a substantially rectangular shape. As shown in FIG. 5, the first groove portion 21 is formed in a pair with the input shaft 15 in between in the central portion of the first rotating body 11. The first rotating body 11 rotates with the input shaft 15 with respect to the housing 2 by the first bearing 7.

  The second rotating body 12 is a disk-like member similar to the first rotating body 11. The upper surface and the lower surface of the second rotating body 12 are arranged in a direction perpendicular to the x axis, that is, a direction parallel to the yz plane. An output shaft 16 is connected to one surface of the second rotating body 12. On the other surface of the second rotating body 12, a second projecting portion 31 serving as a “second engaging portion” is provided. The 2nd protrusion part 31 is formed along the direction orthogonal to the rotating shaft of a torque sensor. The shape of the cross section orthogonal to the longitudinal direction of the second protrusion 31 is substantially rectangular. As shown in FIG. 4, the second projecting portion 31 is formed in a pair on the outer peripheral portion of the second rotating body 12 with the output shaft 16 interposed therebetween. The second rotating body 12 rotates together with the output shaft 16 with respect to the housing 2 by the second bearing 8.

  A strain generating body 13 is disposed between the first rotating body 11 and the second rotating body 12. The strain body 13 is also a disk-like member similar to the first rotating body 11 and the second rotating body 12. The material of the 1st rotary body 11, the 2nd rotary body 12, and the strain body 13 is not specifically limited, Various structural materials, such as a steel material and a nonferrous metal material, can be used.

  As the strain body 13, for example, a material that is elastically deformed by receiving rotational torque generated by the speed reducer 6 is used. As the 1st rotary body 11 and the 2nd rotary body 12, the thing with the favorable slip of the surface which contacts in contrast with the strain body 13 is used suitably. For example, the first rotating body 11 and the second rotating body 12 can be plated with Kaniflon (registered trademark) or the like. It is desirable that the first rotating body 11 and the second rotating body 12 are not deformed.

  Here, the strain body 13 will be described in detail with reference to FIG. As illustrated in FIG. 3, the strain body 13 includes a first structure 17, a second structure 18, a strain body 19, a first protrusion 22, and a second groove 32. Referring to FIGS. 2 and 5, a first protrusion that can be engaged with a surface of the strain generating body 13 facing the first rotating body 11 through a gap in a direction perpendicular to the first groove portion 21 and the input shaft 15. A portion 22 is provided. The first projecting portion 22 becomes a “first engagement receiving portion”. 2 and 4, the surface of the strain generating body 13 facing the second rotating body 12 can be engaged with the second projecting portion 31 through a gap perpendicular to the output shaft 16. A second groove portion 32 is provided. The second groove portion 32 becomes a “second engagement receiving portion”.

  The first groove 21 and the first protrusion 22 constitute the first torque transmission mechanism 20, and the second protrusion 31 and the second groove 32 constitute the second torque transmission mechanism 30. The torque sensor 10 is input to the input shaft 15 from the speed reducer 6 via the first rotating body 11, the first torque transmitting mechanism 20, the strain generating body 13, the second torque transmitting mechanism 30, and the second rotating body 12. Rotational torque is transmitted to the output shaft 16.

  The 1st protrusion part 22 is formed along the 1st direction orthogonal to the rotating shaft of a torque sensor. The first projecting portions 22 are formed at positions corresponding to the first groove portions 21, and are formed in pairs at the center portion of the strain body 13 with the input shaft 15 interposed therebetween. The shape of the cross section orthogonal to the longitudinal direction of the first protrusion 22 is substantially rectangular. The first protrusion 22 is formed corresponding to the shape of the first groove 21. By housing the first protrusion 22 in the first groove 21, the first structure 17 is coupled to the first rotating body 11.

  The 2nd groove part 32 is formed along the 2nd direction orthogonal to the rotating shaft of a torque sensor. The second groove portion 32 is formed at a position corresponding to the second projecting portion 31, and is formed in a pair on the outer peripheral portion of the strain body 13 with the output shaft 16 interposed therebetween. The shape of the cross section orthogonal to the longitudinal direction of the second groove portion 32 is a substantially rectangular shape. The second groove 32 is formed corresponding to the shape of the second protrusion 31. The second direction is orthogonal to the first direction. That is, the angle formed between the direction in which the first protrusion 22 extends and the direction in which the second groove 32 extends is approximately 90 degrees. By housing the second protrusion 31 in the second groove 32, the second structure 18 is coupled to the second rotating body 12.

  The first protrusion 22 is accommodated in the first groove 21. A predetermined gap is formed between the inner surface of the first groove 21 and the outer surface of the first protrusion 22. That is, a gap is formed between the top surface of the first protrusion 22 and the bottom surface of the first groove portion 21 in a direction perpendicular to the x-axis. Further, as shown in FIG. 6, a gap G is formed between the side surface of the first protrusion 22 and the side surface of the first groove portion 21 in the direction around the x axis (rotation direction).

  The second protrusion 31 is accommodated in the second groove 32. A predetermined gap is formed between the inner surface of the second groove 32 and the outer surface of the second protrusion 31. That is, a gap is formed between the top surface of the second protrusion 31 and the bottom surface of the second groove 32 in a direction perpendicular to the x-axis. Further, a gap is formed between the side surface of the second protrusion 31 and the side surface of the second groove 32 in the direction around the x axis (rotation direction).

  As shown in FIG. 3, the strain generating portion 19 connects the first structure 17 and the second structure 18. In the example shown in FIG. 3, four strain generating portions 19 are provided at equal intervals. A detection element 14 is attached to the strain body 13. The detection element 14 is a thin film strain sensor capable of detecting the deformation amount of the strain generating portion 19. A plurality of detection elements 14 are patterned on the strain generating portion 19 by sputtering. A torque acting between the first structure 17 and the second structure 18 is calculated based on the output values of the plurality of detection elements 14.

  Here, before describing the effect of the actuator 1 according to the present embodiment, a torque sensor of a comparative example will be described with reference to FIGS. The comparative example shown in FIGS. 7 to 10 is a torque sensor having a structure in which a torque sensor is divided into an inner ring 101 and an outer ring 102 as in Patent Document 1. The four strain bodies 103 are accommodated in the four engagement recesses 104 formed in the outer ring 102 via gaps G1 to G4, respectively.

  As shown in FIG. 8, only when the axes of the inner ring 101 and the outer ring 102 are completely coincident with each other and the gaps G1 to G4 are exactly the same, the four strain generating bodies 103 are simultaneously formed on the side surfaces of the engaging recess 104. The bridge balance of the resistance of the detection element for detecting the torque is maintained.

  However, in actuality, due to variations in processing accuracy, a piece of the strain generating body 103 hits the engaging recess 104 and a piece hit occurs. Although the axes of the inner ring 101 and the outer ring 102 coincide with each other, but the gaps G1 to G4 are different from each other, the strain generating body 103 and the engaging recess 104 come into contact with each other only at the smallest gap. For example, as shown in FIG. 9, only the upper strain generating body 103 is in contact with the engaging recess 104, and the other three strain generating bodies 103 are not in contact with the engaging recess 104. Further, as shown in FIG. 10, even when the axes of the inner ring 101 and the outer ring 102 are deviated, the strain generating body 103 and the engaging recess 104 come into contact with each other only at the smallest gap.

  In this way, when only one part of the four strain generating bodies 103 hits the corresponding engaging recess 104, and one piece contact occurs, the deformation state of the four strain generating bodies is different, and it is very important to improve the torque detection accuracy. It becomes difficult.

  Next, effects of the torque sensor 10 according to the present embodiment will be described with reference to FIGS. As described above, it is conceivable that the input shaft and the output shaft of the torque sensor are shifted depending on the component processing accuracy and the assembly accuracy. Due to the deviation between the rotation shafts (input shaft and output shaft), a force in the direction other than the torque (other shaft force) is applied to the detection element of the torque sensor, and the accuracy of the torque to be detected is reduced. In general, the reducer often has a vibration component in the axial direction (x-axis direction) and the radial direction (direction perpendicular to the x-axis), and the torque sensor input shaft has an axial direction from the reducer, Radial force is applied. Further, another axial force from a load link coupled to the output shaft is applied to the input shaft of the torque sensor. For this reason, the torque detection accuracy similarly decreases.

  Further, if the rigidity of the bearings (the first bearing 7 and the second bearing 8) that support the input side (first rotating body 11) and the output side (second rotating body 12) is increased, the frictional force increases. It is not practical to increase the bearing rigidity to such an extent that no other axial force is transmitted.

  Therefore, in the present embodiment, the torque sensor 10 has a divided structure of the first rotating body 11, the second rotating body 12, and the strain body 13. The first projecting portion 22 is separated from the first groove portion 21 through a gap in the radial direction and the rotational direction. Further, the second projecting portion 31 is separated from the second groove portion 32 in the radial direction and the rotational direction via a gap. In addition, the magnitude | size of the clearance gap between the 1st protrusion part 22 and the 1st groove part 21, and the gap | interval between the 2nd protrusion part 31 and the 2nd groove part 32 is not specifically limited, It can set suitably.

  Further, the extending direction of the first projecting portion 22 (first engagement receiving portion) formed on the strain body 13 and the extending direction of the second groove portion 32 (second engagement receiving portion) are substantially orthogonal to each other. . The angle formed by the direction in which the first protrusion 22 extends and the direction in which the second groove 32 extends is approximately 90 degrees. For this reason, the extending direction of the first groove portion 21 (first engaging portion) of the first rotating body 11 that houses the first protrusion 22 and the second rotating body 12 housed in the second groove portion 32. The extending direction of the two protruding portions 31 (second engaging portion) is substantially orthogonal.

  Since the torque sensor has the divided structure of the first rotating body 11, the second rotating body 12, and the strain generating body 13, the degree of freedom of the strain generating body 13 in the direction in which the gap is formed is increased. For this reason, it is possible to suppress the torque sensor 10 from being applied with the other axial force in the direction other than the torque from the speed reducer 6 and the other axial force from the output shaft 16, and to increase the torque detection accuracy. Become.

  That is, since the first projecting portion 22 is separated from the first groove portion 21 via a gap, the strain-generating body 13 can be moved up and down even if the rotation axes of the first rotating body 11 and the strain-generating body 13 are shifted. By shifting to the left and right, the contact of each of the first protrusions 22 with the first groove 21 becomes uniform. Further, since the second projecting portion 31 is separated from the second groove portion 32 via a gap, even if the rotational axes of the strain generating body 13 and the second rotating body 12 are deviated, the strain generating body 13 is moved up and down. By shifting to the left and right, the manner in which each of the second protrusions 31 contacts the second groove 32 becomes uniform.

  In this way, the strain generating body 13 can move in a direction other than the rotational direction with respect to the input shaft 15 and the output shaft 16, and as a result, only the rotational torque is applied to the strain generating body 13, and the strain generating body 13 is subjected to strain generation. The bridge balance of the detection element attached to the body 13 is not lost. As a result, it is possible to improve the detection accuracy of the rotational torque by suppressing the contact of the strain generating element and blocking the other axial force.

  As described above, according to the present embodiment, since the torque sensor 10 has the divided structure of the first rotating body 11, the second rotating body 12, and the strain generating body 13, the rotational torque to be detected is detected. It is possible to eliminate the influence of other axial forces other than the above, and to realize highly accurate torque detection.

  Further, according to the present embodiment, since the strain generating body 13 is engaged with each of the first rotating body 11 and the second rotating body 12 with a gap, there is a rotation axis deviation. However, it is possible to alleviate the contact between the engaging portions and improve the torque detection accuracy.

  In the example shown in the drawing, the first groove 21 is formed in the first rotating body 11, the second projecting portion 31 is formed in the second rotating body 12, the first projecting portion 22, and the first projecting portion 22 in the strain generating body 13. Although the two groove part 32 is formed, it is not limited to this.

  For example, a protrusion may be formed on the first rotating body 11 and a groove may be formed on the second rotating body 12. In this case, a groove portion can be formed on the surface of the strain body 13 facing the first rotating body 11, and a protruding portion can be formed on the surface facing the second rotating body 12. Moreover, you may form a protrusion part in any of the 1st rotary body 11 and the 2nd rotary body 12. FIG. In this case, groove portions are formed on both surfaces of the strain body 13. Furthermore, a groove portion may be formed in either the first rotating body 11 or the second rotating body 12. In this case, protrusions are formed on both sides of the strain body 13.

<Embodiment 2>
In the first embodiment, the shape of the cross section orthogonal to the longitudinal direction of the first protrusion 22 is substantially rectangular, and the first groove 21 is formed corresponding to the shape of the first protrusion 22. A gap is formed between the side surface of the first protrusion 22 and the side surface of the first groove portion 21 in the direction around the x axis. In the first embodiment, the shape of the cross section orthogonal to the longitudinal direction of the second protrusion 31 is substantially rectangular, and the second groove 32 is formed corresponding to the shape of the second protrusion 31. In addition, a gap is formed between the side surface of the second protrusion 31 and the side surface of the second groove 32 in the direction around the x axis.

  However, when the first rotating body 11, the strain generating body 13 and the second rotating body 12 rotate, the actuator has a backlash around the x axis of the first rotating body 11, the strain generating body 13 and the second rotating body 12. The structure which can suppress sticking may be sufficient.

  Therefore, the first torque transmission mechanism of the present embodiment is configured such that at least a part of the side surface of the first projecting portion and the side surface of the first groove portion facing each other around the x-axis are substantially in surface contact. In addition, the second torque transmission mechanism of the present embodiment is configured such that at least a part of the side surface of the second projecting portion and the side surface of the second groove portion facing each other around the x-axis are substantially in surface contact. In addition, since the actuator of this Embodiment is set as the structure substantially the same as the actuator 1 of Embodiment 1, the overlapping description is abbreviate | omitted and it demonstrates using the same code | symbol to an identical component.

  For example, as shown in FIG. 11, the shape of the cross section orthogonal to the longitudinal direction at the tip of the first protrusion 23 is formed in a substantially trapezoidal shape. On the other hand, the cross-sectional shape orthogonal to the longitudinal direction of the first groove portion 24 is formed in a substantially trapezoidal shape. And as shown in FIG. 12, the inclined surface 23a of the 1st protrusion part 23 and the inclined surface 24a of the 1st groove part 24 are substantially surface-contacting. That is, the first protrusion 23 and the first groove 24 are engaged with no gap around the x axis.

  Moreover, as shown in FIG. 11, the shape of the cross section orthogonal to the longitudinal direction in the front-end | tip part of the 2nd protrusion part 33 is formed in the substantially trapezoid shape. On the other hand, the cross-sectional shape orthogonal to the longitudinal direction of the second groove 34 is formed in a substantially trapezoidal shape. The inclined surface 33a of the second projecting portion 33 and the inclined surface 34a of the second groove portion 34 are substantially in surface contact. That is, the 2nd protrusion part 33 and the 2nd groove part 34 are engaged without the clearance gap around the x-axis.

  With such a configuration, when the torque sensor rotates, rattling around the x-axis of the first rotating body 11, the strain generating body 13, and the second rotating body 12 can be suppressed. Therefore, the detection accuracy of the torque sensor can be improved.

  Moreover, as described above, the tip of the first protrusion 23 is formed in a substantially trapezoidal shape, the first groove 24 is formed so as to correspond to the shape of the first protrusion 23, and the tip of the second protrusion 33 is formed. The portion is formed in a substantially trapezoidal shape, and the second groove portion 34 is formed so as to correspond to the shape of the second protruding portion 33. Therefore, when the amount of pushing of the strain body 13 in the x-axis direction by the second rotating body 12 is adjusted, the inclined surface 23a of the first protrusion 23, the inclined surface 24a of the first groove 24, and the second The inclined surface 33a of the protruding portion 33 and the inclined surface 34a of the second groove portion 34 can be brought into substantially surface contact.

  Here, for example, referring to FIG. 1, the second rotating body 12 includes a flange portion 12 a that protrudes outward from the outer peripheral surface of the second rotating body 12, and the x-axis of the second rotating body 12. When the position in the direction is configured to depend on the thickness of the spacer 41 and the shim 42 arranged between the flange portion 12a of the second rotating body 12 and the first bearing 7, the spacer 41 and the shim By adjusting the thickness of 42, the pushing amount of the strain body 13 in the x-axis direction by the second rotating body 12 may be adjusted. Incidentally, the position of the second rotating body 12 in the x-axis direction is fixed by the flange portion 12a of the second rotating body 12 being sandwiched between the second bearing 8 and the spacer 41. Thereby, by adjusting the thickness of the spacer 41 and the shim 42, the inclined surface 23a of the first protruding portion 23, the inclined surface 24a of the first groove portion 24, and the inclined surface 33a of the second protruding portion 33 The inclined surface 34a of the second groove 34 can be brought into substantially surface contact.

  In addition, although the 1st protrusion part 23 and the 2nd protrusion part 33 of this Embodiment have formed the front-end | tip part in substantially trapezoid shape, the 1st rotary body 11, the strain body 13, and the 2nd rotary body 12 are the same. In a state where the rotation axis is arranged on the x-axis, the inclined surfaces are arranged symmetrically about the axis extending in the radial direction when viewed from the x-axis direction, and the first protrusion 23 and the second protrusion What is necessary is just the shape where the space | interval of the opposing inclined surface in 33 becomes narrow in an axial direction. Further, the first groove portion 24 has an inclined surface substantially in surface contact with the inclined surface of the first protruding portion 23, and the second groove portion 34 has an inclined surface substantially in surface contact with the inclined surface of the second protruding portion 33. If you do.

  The present invention is not limited to the above-described embodiment, and can be changed as appropriate without departing from the spirit of the present invention. The shapes and combinations of the constituent members shown in the embodiments are merely examples, and various changes can be made based on design requirements and the like.

DESCRIPTION OF SYMBOLS 1 Actuator 2 Housing | casing 3 Encoder 4 Rotor 5 Stator 6 Reducer 7 1st bearing 8 2nd bearing 9 Reducer output shaft 10 Torque sensor 11 1st rotary body 12 2nd rotary body, 12a Flange part 13 Strain body 14 Detection Element 15 Input shaft 16 Output shaft 17 First structure 18 Second structure 19 Straining portion 20 First torque transmission mechanism 21 First groove portion 22 First protrusion portion 23 First protrusion portion, 23a Inclined surface 24 First groove portion, 24a inclined surface 30 second torque transmission mechanism 31 second protruding portion 32 second groove portion 33 second protruding portion, 33a inclined surface 34 second groove portion, 34a inclined surface 41 spacer 42 shim

Claims (2)

A first rotating body having a first engaging portion extending in a first direction and rotatable around an input shaft;
A second rotating body having a second engaging portion that is rotatable around an output shaft and extends in a second direction substantially orthogonal to the first direction;
A first bearing that supports the first rotating body with respect to a housing;
A second bearing that supports the second rotating body with respect to the housing;
A first engagement receiving portion engageable via a gap in a direction perpendicular to the first engagement portion and the input shaft; and a gap in a direction perpendicular to the second engagement portion and the output shaft. A strain generating body that has a second engagement receiving portion that can be engaged, and transmits a rotational torque of the input shaft to the output shaft;
A detection element attached to the strain body and measuring the strain of the strain body due to the rotational torque;
An actuator. At least a portion of the side surface of the first engagement portion and the side surface of the first engagement receiving portion facing each other around the input shaft are in surface contact with each other,
2. The actuator according to claim 1, wherein at least a part of a side surface of the second engagement portion and a side surface of the second engagement receiving portion facing each other around the output shaft are in surface contact.

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