JP5817371B2 - Torque measuring device - Google Patents

Description

  The present invention relates to a torque measuring device.

  As this type of technology, Patent Document 1 discloses a load cell including a strain generating body and a strain gauge. The strain generating body includes an outer ring that is bolted to one of the input side or the output side, an inner ring that is bolted to the other of the input side or the output side, and a spoke part that connects the outer ring and the inner ring to form a strain generating part. , Is composed of. A strain gauge is provided in the spoke part.

JP 2009-288187

  However, the load cell of Patent Document 1 may cause a slight slip when transmitting high torque from the input side to the output side. This is because the bolt joint has an inevitable gap between the bolt and the bolt hole.

  An object of the present invention is to provide a technique for reducing the effect of slippage due to the adoption of bolt joints.

  According to a first aspect of the present invention, there is provided a torque measuring device for measuring torque transmitted from an input side to an output side, wherein the first counterpart member that is one of the input side or the output side is used. A first structure to be coupled; a second structure coupled to a second mating member that is the other of the input side or the output side; and a coupling that connects the first structure and the second structure. And a deformation amount detecting means capable of detecting a deformation amount of the strain generating portion, wherein the first structure is coupled to the first mating member by bolt joining, and The first structure and the first mating member are fitted together with a play smaller than the play of the bolt joint in the torque acting direction as the direction in which the torque acts, due to the combination of the protrusion and the groove. A torque measuring device is provided. According to the above configuration, it is possible to reduce the influence of slipping due to the use of bolt joining for coupling the first structure and the first mating member.

  The second structure is coupled to the second mating member by bolt joining, and the second structure and the second mating member are combined with a protrusion and a groove, They are engaged with each other with a play smaller than the play of the bolt joint in the torque acting direction. According to the above configuration, it is possible to reduce the influence of slipping due to the use of bolt joint for coupling the second structure and the second mating member.

  The protrusion or the groove formed in the first structure so that the first structure and the first mating member are fitted to each other is formed to extend in a first direction, and The protrusion or the groove formed in the second structure so that the second structure and the second mating member fit together is a second direction orthogonal to the first direction. It is extended and formed. According to the above configuration, when viewed from the torque measuring device, the first mating member is slidable in the first direction, and the second mating member is orthogonal to the first direction. Since it is slidable in the second direction, alignment work of the first mating member, the torque measuring device, and the second mating member, which is performed before the bolt joining, is easy.

  According to a second aspect of the present invention, there is provided a torque measuring device for measuring torque transmitted from the input side to the output side, wherein the first counterpart member that is one of the input side or the output side is used. A first structure to be coupled; a second structure coupled to a second mating member that is the other of the input side or the output side; and a coupling that connects the first structure and the second structure. And a deformation amount detecting means capable of detecting a deformation amount of the strain generating portion, wherein the first structure is coupled to the first mating member by bolt joining, and The first structure and the first mating member are wedge-engaged so as to eliminate play in the torque acting direction as the direction in which the torque acts by combining a tapered projecting portion and a tapered groove portion. A measuring device is provided. According to the above configuration, it is possible to solve the influence of slipping due to the use of bolt joining for coupling the first structure and the first mating member.

  The second structure is coupled to the second mating member by bolt joining, and the second structure and the second mating member are formed by a tapered protrusion and a tapered groove. By the combination, wedge engagement is performed so as to eliminate play in the torque acting direction as the direction in which the torque acts. According to the above configuration, it is possible to solve the influence of slipping due to the use of bolt joint for coupling the second structure and the second mating member.

  The tapered protrusion or the tapered groove formed in the first structure for wedge engagement between the first structure and the first mating member is formed extending in the first direction. The tapered protrusion or the tapered groove formed in the second structure so that the second structure and the second mating member are wedge-engaged with respect to the first direction. And extending in a second direction orthogonal to each other. According to the above configuration, when viewed from the torque measuring device, the first mating member is slidable in the first direction, and the second mating member is orthogonal to the first direction. Since it is slidable in the second direction, alignment work of the first mating member, the torque measuring device, and the second mating member, which is performed before the bolt joining, is easy.

  According to the invention of the present application, it is possible to reduce the influence of slipping due to the use of bolt joining for coupling the first structure and the first mating member.

FIG. 1 is a cross-sectional view of a principal part of a joint portion of a robot. (First embodiment) FIG. 2 is a front view of the torque sensor. (First embodiment) 3 is a cross-sectional view taken along line III-III in FIG. (First embodiment) 4 is a cross-sectional view taken along line IV-IV in FIG. (First embodiment) 5 is a cross-sectional view taken along line VV in FIG. (First embodiment) FIG. 6 is a view similar to FIG. 5 and showing the second embodiment.

(First embodiment)
Hereinafter, the first embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 shows an example in which the torque sensor 1 of the present embodiment is incorporated in the joint 3 of the robot 2. As shown in FIG. 1, the joint part 3 of the robot 2 includes a first joint mechanism 4 corresponding to the upper arm, a second joint mechanism 5 corresponding to the forearm, a servo driver 6, and a servo motor 7 (torque generating means, Drive source) and a speed reducer 8.

  The servo motor 7 and the speed reducer 8 are supported at the tip of the first joint mechanism 4 so as not to rotate.

  The servo motor 7 rotates a rotating shaft (not shown) based on a torque command signal received from the servo driver 6. The servo motor 7 has an absolute encoder 9 that detects the rotation angle of the rotating shaft. The absolute encoder 9 feeds back the detected rotation angle of the rotating shaft to the servo driver 6.

  The speed reducer 8 is for amplifying the torque output from the servo motor 7. The speed reducer 8 has a primary side fastening member 10 (first counterpart member). The primary side fastening member 10 is coupled to the torque sensor 1.

  The second joint mechanism 5 has a secondary side fastening member 11 (second counterpart member). The secondary side fastening member 11 is coupled to the torque sensor 1.

  The torque sensor 1 measures the torque transmitted from the primary side fastening member 10 (input side) to the secondary side fastening member 11 (output side). The torque sensor 1 feeds back the measured torque to the servo driver 6 as a torque signal.

  With the above configuration, the servo motor 7 generates torque based on the torque command signal generated by the servo driver 6, and the generated torque is amplified by the speed reducer 8 and then the second joint mechanism via the torque sensor 1. 5 is output.

  Next, the configuration of the torque sensor 1 will be described in detail. As shown in FIG. 2, the torque sensor 1 includes a first structure 12, a second structure 13, and four strain generating portions 14.

  The first structure 12 in FIG. 2 is a portion that is coupled to the primary side fastening member 10. A plurality of female screws 15 for bolt joining are formed in the first structure 12. The first structure 12 can be attached to the primary-side fastening member 10 by passing a bolt through a bolt-joining bolt through-hole formed in the primary-side fastening member 10 and screwing the bolt into the bolt-joining female screw 15. Bolted.

  As shown in FIG. 4, a first direction 17 (first direction orthogonal to the rotation axis C of the torque sensor 1) is formed on the first joint surface 16 that is a surface on the primary side fastening member 10 side of the first structure 12. The elongated first protrusions 18 (protrusions) are formed in pairs so as to sandwich the rotation axis C. As shown in FIG. 5, the shape of the cross section orthogonal to the longitudinal direction of the 1st protrusion 18 is a substantially rectangular shape. And the 1st protrusion body 18 of the 1st structure 12 is accommodated in the 1st protrusion body accommodation groove | channel 30 currently formed in the primary side fastening member 10. FIG. At this time, the gap g between the first ridge body 18 and the first ridge body housing groove 30 in the circumferential direction of the torque sensor 1 (that is, the torque acting direction Td) is a bolt joint in the torque acting direction Td. It is set smaller than play. Accordingly, it is possible to reduce the influence of slipping due to the use of bolt joining for the connection between the first structure 12 and the primary side fastening member 10.

  The second structure 13 in FIG. 2 is a portion that is coupled to the secondary side fastening member 11. The second structure 13 is annularly arranged on the outer peripheral side of the first structure 12. In the second structure 13, a plurality of female screws 19 for bolt connection are formed. The second structure 13 is attached to the secondary side fastening member 11 by passing the bolt through the bolt joining bolt through hole formed in the secondary side fastening member 11 and screwing the bolt into the bolt joining female screw 19. It is bolted to it.

  As shown in FIG. 3, the second joint surface 20, which is the surface on the secondary side fastening member 11 side of the second structure 13, is orthogonal to the rotational axis C of the torque sensor 1 and the first protrusion. The elongated second ridge body accommodation groove 22 (groove) along the second direction 21 (second direction) orthogonal to the longitudinal direction of the body 18 (first direction 17) sandwiches the rotation axis C. A pair is formed. The shape of the cross section orthogonal to the longitudinal direction of the second protrusion housing groove 22 is substantially rectangular. And the 2nd protrusion body accommodation groove | channel 22 of the 2nd structure 13 accommodates the 2nd protrusion body 31 currently formed in the secondary side fastening member 11. FIG. At this time, the gap between the second protrusion 31 and the second protrusion accommodating groove 22 in the circumferential direction of the torque sensor 1 (that is, the torque acting direction Td) is the first protrusion 18 in FIG. And a gap between the first protrusion body housing groove 30 and the bolt joint play in the torque acting direction Td. Therefore, it is possible to reduce the influence of slipping due to the use of the bolt joint for coupling the second structure 13 and the secondary side fastening member 11.

  As shown in FIG. 2, each strain generating portion 14 connects the first structure 12 and the second structure 13. A plurality of thin film strain sensors 32 (deformation amount detection means) capable of detecting the deformation amount of the strain generation portion 14 are patterned in the strain generation portion 14 by sputtering. The servo driver 6 in FIG. 1 calculates the torque acting between the first structure 12 and the second structure 13 based on the output values of the plurality of strain sensors 32 and feedback-controls the servo motor 7.

  Although the first embodiment of the present invention has been described above, the first embodiment basically has the following features.

(1) The torque sensor 1 (torque measuring device) is for measuring the torque transmitted from the primary side fastening member 10 (input side) to the secondary side fastening member 11 (output side). The torque sensor 1 includes a first structure 12 coupled to a primary side fastening member 10 (a first counterpart member that is one of the primary side fastening member 10 or the secondary side fastening member 11), and a secondary side fastening member 11. The second structure 13 coupled to (the second mating member that is the other of the primary side fastening member 10 or the secondary side fastening member 11), and the strain generation that connects the first structure 12 and the second structure 13. Part 14 and a strain sensor 32 (deformation amount detecting means) capable of detecting the deformation amount of the strain generating part 14. The first structure 12 is coupled to the primary side fastening member 10 by bolt joining. The first structure 12 and the primary side fastening member 10 have a torque action as a direction in which a torque acts by a combination of the first protrusion 18 (protrusion) and the first protrusion housing groove 30 (groove). They are engaged with each other with a smaller play than the above-described bolt joint play in the direction Td. According to the above configuration, it is possible to reduce the influence of slipping due to the use of the bolt joint for coupling the first structure 12 and the primary side fastening member 10.

  Note that, when slippage occurs between the first structure 12 and the primary side fastening member 10, stepped vibration is generated at the distal end portion of the second joint mechanism 5, for example, provided at the distal end portion of the second joint mechanism 5. The delicate movement of the hand is obstructed. In this regard, in the above embodiment, the slip between the first structure 12 and the primary side fastening member 10 is reduced, which contributes to the delicate movement of the hand.

(2) The second structure 13 is coupled to the secondary side fastening member 11 by bolt joining. The second structure 13 and the secondary side fastening member 11 are bolt-bonded in the torque acting direction Td by the combination of the second protrusion 31 (protrusion) and the second protrusion accommodating groove 22 (groove). They fit together in a smaller play than play. According to the above configuration, it is possible to reduce the influence of slippage due to the use of bolt joining for the coupling between the second structure 13 and the secondary side fastening member 11.

  Note that when slippage occurs between the second structure 13 and the secondary side fastening member 11, stepped vibration is generated at the distal end portion of the second joint mechanism 5, for example, at the distal end portion of the second joint mechanism 5. The delicate movement of the provided hand is obstructed. In this regard, in the above embodiment, the slip between the second structure 13 and the secondary side fastening member 11 is reduced, which contributes to the delicate movement of the hand.

(3) The first protrusion 18 formed in the first structure 12 so that the first structure 12 and the primary side fastening member 10 are fitted to each other is formed to extend in the first direction 17. The second projecting body accommodation groove 22 formed in the second structure 13 so that the second structure 13 and the secondary side fastening member 11 are fitted to each other is perpendicular to the first direction 17. It extends in two directions 21. According to the above configuration, when viewed from the torque sensor 1, the primary side fastening member 10 is slidable in the first direction 17, and the secondary side fastening member 11 is in the second direction 21 orthogonal to the first direction 17. Therefore, alignment work of the primary side fastening member 10, the torque sensor 1, and the secondary side fastening member 11 performed before the bolt joining is easy.

  In other words, as shown in FIG. 2, the longitudinal direction of the first protrusion 18 and the longitudinal direction of the second protrusion housing groove 22 are orthogonal to each other. Thereby, even if the center axis | shaft of the primary side fastening member 10 and the center axis | shaft of the secondary side fastening member 11 do not correspond, the torque sensor 1 is satisfactory with respect to the primary side fastening member 10 and the secondary side fastening member 11. Can be combined.

  That is, according to the first embodiment, there is provided a solution that simultaneously satisfies the fastening function capable of reliably transmitting torque without causing a positional shift and the aligning function following the primary side central axis and the secondary side central axis. Will be.

  Although the first embodiment of the present invention has been described above, the first embodiment can be modified as follows.

  In the first embodiment, as shown in FIG. 4, the first protrusion 18 is provided in the first structure 12, and the first protrusion accommodation groove 30 is provided in the primary side fastening member 10. However, instead of this, the first protrusion 12 may be provided in the first structure 12, and the first protrusion 18 may be provided in the primary side fastening member 10.

  In the first embodiment, as shown in FIG. 3, the second projecting body accommodation groove 22 is provided in the second structure 13, and the second projecting body 31 is provided in the secondary side fastening member 11. However, instead of this, the second ridge body 31 may be provided in the second structure 13, and the second ridge body accommodation groove 22 may be provided in the secondary side fastening member 11.

  In the first embodiment, the first structure 12 is coupled to the primary side fastening member 10, and the second structure 13 is coupled to the secondary side fastening member 11. However, instead of this, the first structure 12 may be coupled to the secondary side fastening member 11 and the second structure 13 may be coupled to the primary side fastening member 10.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG. Here, the present embodiment will be described with a focus on differences from the first embodiment, and overlapping descriptions will be omitted as appropriate. In addition, in principle, the same reference numerals are assigned to components corresponding to the respective components of the first embodiment.

  As shown in FIG. 5, in the first embodiment, the first structure 12 of the torque sensor 1 is formed with a first protrusion 18 having a substantially rectangular cross section, and the primary side fastening member 10. The first protrusion housing groove 30 having a substantially rectangular cross section is formed. However, instead of this, in the present embodiment, the first structure 12 of the torque sensor 1 is formed with a tapered first protrusion 50, and the primary-side fastening member 10 has a tapered first protrusion. A strip accommodation groove 51 is formed. The tapered first protrusion 50 has a pair of tapered surfaces 50 a that are inclined with respect to the first joint surface 16 of the first structure 12. Similarly, the tapered first protrusion housing groove 51 has a pair of tapered surfaces 51a. And as shown in FIG. 6, each taper surface 50a of the 1st protrusion body 50 with a taper makes surface contact in a taper shape with respect to each pair of taper surface 51a of the 1st protrusion body accommodation groove | channel 51 with a taper. Thus, the first structure 12 and the primary side fastening member 10 are wedge-engaged, and the play in the torque acting direction Td between the first structure 12 and the primary side fastening member 10 disappears. That the play in the torque acting direction Td disappears, that is, there is no gap corresponding to the gap g in FIG.

  Similarly, the second structure 13 and the secondary-side fastening member 11 include a tapered protrusion (corresponding to the tapered first protrusion 50 in FIG. 6) and a tapered groove (the tapered first in FIG. 6). (Corresponding to the projecting body accommodating groove 51), the wedge is engaged so as to eliminate play in the torque acting direction Td. Thereby, the play in the torque acting direction Td between the second structure 13 and the secondary side fastening member 11 disappears. That the play in the torque acting direction Td disappears, that is, there is no gap corresponding to the gap g in FIG.

  The second embodiment of the present invention has been described above. In short, the second embodiment has the following features.

(4) The torque sensor 1 (torque measuring device) is for measuring the torque transmitted from the primary side fastening member 10 (input side) to the secondary side fastening member 11 (output side). The torque sensor 1 includes a first structure 12 coupled to a primary side fastening member 10 (a first counterpart member that is one of the primary side fastening member 10 or the secondary side fastening member 11), and a secondary side fastening member 11. The second structure 13 coupled to (the second mating member that is the other of the primary side fastening member 10 or the secondary side fastening member 11), and the strain generation that connects the first structure 12 and the second structure 13. Part 14 and a strain sensor 32 (deformation amount detecting means) capable of detecting the deformation amount of the strain generating part 14. The first structure 12 is coupled to the primary side fastening member 10 by bolt joining. The first structure 12 and the primary-side fastening member 10 are provided with torque by combining a tapered first protrusion 50 (tapered protrusion) and a tapered first protrusion receiving groove 51 (tapered groove). The wedge is engaged so as to eliminate play in the acting direction Td. According to the above configuration, it is possible to solve the influence of slipping due to the use of bolt joining for coupling the first structure 12 and the primary side fastening member 10.

(5) Moreover, the 2nd structure 13 is couple | bonded with the secondary side fastening member 11 by bolt joining. The second structure 13 and the secondary side fastening member 11 correspond to a tapered protrusion (corresponding to the tapered first protrusion 50) and a tapered groove (tapered first protrusion housing groove 51). ) To engage the wedge so as to eliminate play in the torque acting direction Td. According to the above configuration, it is possible to solve the influence of slipping due to the use of the bolt joint for coupling the second structure 13 and the secondary side fastening member 11.

(6) Further, since the first structure 12 and the primary side fastening member 10 are wedge-engaged, the tapered first protrusion 50 formed in the first structure 12 extends in the first direction 17. The tapered first protrusion 50 (or the tapered first protrusion) formed in the second structure 13 so that the second structure 13 and the secondary fastening member 11 are wedge-engaged. The body accommodating groove 51) is formed so as to extend in the second direction 21 orthogonal to the first direction 17. According to the above configuration, when viewed from the torque sensor 1, the primary side fastening member 10 is slidable in the first direction 17, and the secondary side fastening member 11 is in the second direction 21 orthogonal to the first direction 17. Therefore, alignment work of the primary side fastening member 10, the torque sensor 1, and the secondary side fastening member 11 performed before the bolt joining is easy.

  That is, the second embodiment also provides a solution that simultaneously satisfies the fastening function capable of reliably transmitting torque without causing a positional shift and the aligning function based on the primary side central axis and the secondary side central axis. It will be.

DESCRIPTION OF SYMBOLS 1 Torque sensor 2 Robot 3 Joint part 4 1st joint mechanism 5 2nd joint mechanism 10 Primary side fastening member 11 Secondary side fastening member 12 First structure 13 Second structure 14 Strain generation part

Claims (4)

A torque measuring device for measuring torque transmitted from a primary side fastening member to a secondary side fastening member,
A first structure engaged with the primary side fastening member;
A second structure disposed on the outer peripheral side of the first structure and engaged with the secondary side fastening member;
A strain generating portion connecting the first structure and the second structure;
Deformation amount detecting means capable of detecting the deformation amount of the strain generating portion;
With
The first joint surface, which is the surface on the primary-side fastening member side of the first structure, is disposed so as to sandwich the rotation shaft in a first direction orthogonal to the rotation shaft of the torque measuring device, A pair of protrusions or grooves extending along the first direction is formed,
The protruding portion or the groove portion of the first structure can be engaged with a groove portion or a protruding portion that the primary side fastening member has,
The strain generating portion extends substantially along a second direction orthogonal to the first direction, and connects the first structure and the second structure,
Torque measuring device. The torque measuring device according to claim 1,
The second joint surface, which is the surface on the secondary side fastening member side of the second structure, is disposed so as to sandwich the rotating shaft in the second direction, and extends along the second direction. A pair of protrusions or grooves are formed,
The projecting portion or the groove portion of the second structure can be engaged with a groove portion or a projecting portion of the secondary side fastening member.
Torque measuring device. The torque measuring device according to claim 1 or 2,
The cross-sectional shape of the protruding portion or the groove portion of the first structure body is a substantially rectangular shape or a tapered shape for wedge engagement.
Torque measuring device. The torque measuring device according to claim 2,
The cross-sectional shape of the projecting portion or the groove portion of the second structure is a substantially rectangular shape or a tapered shape for wedge engagement.
Torque measuring device.

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