Torque Meters and Measurement Systems

Abstract

To reduce the hysteresis of the measurement carried out by a torque meter.SOLUTION: Provided is a torque meter 1 comprising a first disc part 12 in which the flange of a first revolving shaft 3 is fastened by a bolt, a second disc part 13 in which the flange of a second revolving shaft 4 is fastened by a bolt, and a strain part 11 that connects the second disc part 13 and the first disc part 12, with a strain gauge 15 detecting the strain occurring to the strain part 11 due to a torque transmitted between the first revolving shaft 3 and the second revolving shaft 4. The bolt periphery of the first disc part 12 and the second disc part 13 is formed into a shape protruding in the flange direction so as to come into contact with the flanges to be fastened in only the bolt periphery.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a technique for measuring torque transmitted by a rotating shaft. [Background technology]

[0002] A torque meter 9 shown in FIG. 10a is known as a technique for measuring the torque transmitted by a rotating shaft (for example, see Patent Document 1). FIG. 10a is a side view of the torque meter 9 with a part cut away, and the hatched area represents the cross section after cutting away. As shown in the figure, this torque meter 9 has a drive side flange 92 provided at one axial end of a hollow cylindrical body 91, and a load side flange 93 provided at the other end. The central portion in the axial direction of the hollow body 91 is formed thin, and a strain gauge 94 is fixed to the thin portion of the inner peripheral surface of the hollow body 91.

[0003] As shown in FIG. 10b, a flange 101 of a drive side rotating shaft 100 is fastened to a drive side flange portion 92 of the torque meter 9 with bolts, and a flange 111 of a load side rotating shaft 110 is fastened to a load side flange portion 93 with bolts.

[0004] In such a torque meter 9, the torque transmitted between the drive side rotating shaft 100 and the load side rotating shaft 110 is measured by the strain gauge 94 as strain in the thin-walled portion of the inner circumferential surface of the hollow body portion 91. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2005-321335 A Summary of the Invention [Problem to be solved by the invention]

[0006] The torque meter 9 shown in Figures 10a and 10b has a problem in that hysteresis occurs in the measurement, and the characteristics of the hysteresis that occurs change depending on the rigidity of the flange 101 of the rotating shaft 100 on the drive side and the rigidity of the flange 111 of the rotating shaft 110 on the load side.

[0007] F1 and F2 in FIG. 11a show an example of the load torque-error characteristics when the load torque applied to the torque meter is changed successively from 0 to a predetermined positive value, from the predetermined positive value to a predetermined negative value, and from the predetermined negative value to 0, and hysteresis is generated.

[0008] In FIG. 11a, F1 shows the characteristics when the flange thickness is thinner than F2, and as shown in FIGS. 10b and 10c, when the thickness d1 of flange 101 and the thickness d2 of flange 111, which are factors related to rigidity, differ, the hysteresis characteristics that occur will differ.

[0009] Also, Fig. 11b shows an example of the flange thickness-sensitivity characteristic, and as shown in Fig. 10b and 10c, if the thickness d1 of flange 101 and the thickness d2 of flange 111, which are elements related to rigidity, differ, the sensitivity of the torque meter measurement will differ. Note that Fig. 11b shows the flange thickness-sensitivity characteristic, with the sensitivity set to 0 when the flange thickness is a predetermined reference thickness.

[0010] As described above, the torque meter 9 shown in FIGS. 10a and 10b has a problem in that the sensitivity varies depending on the rigidity of the flange 101 of the driving shaft 100 and the rigidity of the flange 111 of the load shaft 110.

[0011] Such measurement hysteresis and changes in sensitivity and hysteresis characteristics depending on the flange rigidity of the rotating shaft to be fastened have been obstacles to high-precision torque measurement in torque meters. An object of the present invention is to perform torque measurement with higher accuracy. [Means for solving the problem]

[0012] In order to achieve the above object, the present invention provides a torque meter for detecting torque, the torque meter comprising a first disk part connected by a bolt to a first flange which is a flange of a first rotating shaft, a second disk part connected by a bolt to a second flange which is a flange of a second rotating shaft, a strain-flexing part connecting the first disk part and the second disk part, and a strain detection means for detecting a strain generated in the strain-flexing part, wherein at least a part of an area around a bolt hole or a screw hole through which a bolt connecting the first disk part and the first flange is inserted on a surface of the first disk part which faces the first flange when the first flange is connected has a shape that protrudes in the direction of the first flange so that the only place where the first disk part and the first flange abut in the axial direction when the first flange is connected is the part in question.

[0013] In such a torque meter, at least a portion of the area around a bolt hole or screw hole through which a bolt connecting the second disk portion and the second flange is inserted on the surface of the second disk portion that faces the second flange when the second flange is connected may be shaped to protrude toward the second flange so that the only point where the second disk portion and the second flange abut in the axial direction when the second flange is connected is the said portion.

[0014] In order to achieve the above object, the present invention provides a measurement system including a first rotating shaft, a second rotating shaft, and a torque meter for detecting torque transmitted between the first rotating shaft and the second rotating shaft, the torque meter including a first disk portion, a second disk portion, a strain-flexing portion connecting the first disk portion and the second disk portion, and a strain detection means for detecting strain generated in the strain-flexing portion. A first flange is provided at an end of the first rotating shaft, which is a flange connected to the first disk portion by a bolt, and a second flange is provided at an end of the second rotating shaft, which is a flange connected to the second disk portion by a bolt, and at least a part of an area around a bolt hole or a screw hole, through which a bolt connecting the first disk portion is inserted, on a surface of the first flange facing the first disk portion, is shaped to protrude toward the first disk portion so that the first flange and the first disk portion come into axial contact only at the part.

[0015] In this measurement system, at least a portion of the area surrounding a bolt hole or screw hole through which a bolt connecting the second disk portion is inserted on the surface of the second flange facing the second disk portion may be shaped to protrude toward the second disk portion so that this portion is the only point where the second flange and the second disk portion abut in the axial direction.

[0016] In order to achieve the above object, the present invention provides a measurement system including a first rotating shaft, a second rotating shaft, and a torque meter for detecting torque transmitted between the first rotating shaft and the second rotating shaft, the torque meter including a first disk portion, a second disk portion, a strain-flexing portion connecting the first disk portion and the second disk portion, and a strain detection means for detecting strain generated in the strain-flexing portion. Also, a first flange that is a flange connected to the first disk portion with a bolt is provided on an end of the first rotating shaft, and a second flange that is a flange connected to the second disk portion with a bolt is provided on an end of the second rotating shaft. Furthermore, the measurement system is provided with a first annular member, which is an annular member having a hole, and the first annular member is disposed between the first flange and the first disk portion so that the first flange and the first disk portion do not directly abut in the axial direction, and the first flange and the first disk portion are connected in a manner such that a bolt connecting the first flange and the first disk portion is passed through a hole in the first annular member between the first flange and the first disk portion.

[0017] In such a measurement system, a second annular member which is an annular member having a hole may be provided, and the second annular member may be disposed between the second flange and the second disk portion so that the second flange and the second disk portion do not directly abut in the axial direction, and the second flange and the second disk portion may be connected in such a manner that a bolt connecting the second flange and the second disk portion is passed through a hole in the second annular member between the second flange and the second disk portion.

[0018] According to the torque meter and measurement system described above, the points where the first disk and the first flange come into axial contact and the points where the second disk and the second flange come into axial contact are concentrated in small areas around the bolt, so that it is possible to suppress changes in stress distribution according to differences in thickness and rigidity of the first flange and the second flange and the magnitude of the applied torque. This makes it possible to keep the measurement hysteresis of the torque meter small, and also to suppress changes in measurement hysteresis and measurement sensitivity due to differences in thickness and rigidity of the first flange and the second flange, thereby achieving high-precision torque measurement. Effect of the Invention

[0019] As described above, according to the present invention, torque measurement can be performed with higher accuracy. [Brief description of the drawings]

[0020] [Figure 1] 1 is a diagram showing a configuration of a torque measuring device and a measurement system according to an embodiment of the present invention; [Diagram 2] FIG. 1 is a diagram showing a torque meter according to an embodiment of the present invention. [Diagram 3] FIG. 2 is a diagram showing a configuration for detecting rotation of a torque measuring device according to an embodiment of the present invention. [Figure 4] FIG. 2 is a diagram showing a structure for coupling a rotating shaft to a torque meter according to an embodiment of the present invention. [Diagram 5] FIG. 2 is a diagram showing the periphery of a bolt hole of the torque meter according to the embodiment of the present invention. [Figure 6] 1 is a diagram showing the periphery of a screw hole and a through hole of a torque meter according to an embodiment of the present invention. FIG. [Figure 7] FIG. 11 is a diagram showing another example of the configuration of a torque meter according to an embodiment of the present invention. [Figure 8] FIG. 11 is a diagram showing another example of the configuration of a torque meter according to an embodiment of the present invention. [Figure 9] FIG. 11 is a diagram showing another example of the configuration of a torque meter according to an embodiment of the present invention. [Figure 10] FIG. 1 shows a known torque meter. [Figure 11] FIG. 1 illustrates a problem to be solved by the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] An embodiment of the present invention will be described. FIG. 1a shows the configuration of a torque measuring device according to this embodiment. In FIG. 1a, FIG. 1a1 shows a front view of the torque measuring device, FIG. 1a2 shows a side view of the torque measuring device, and FIG. 1a3 shows a rear view of the torque measuring device. As shown in the figure, the torque measuring device is composed of a torque meter 1 and a stator 2. The stator 2 has an annular ring portion 21. Using the torque measuring device, for example, a measurement system as shown in FIG. 1b is configured. In the measurement system of Fig. 1b, a first flange 31 which is a flange provided at an end of a first rotating shaft 3 is connected to the front side of the torque meter 1, and a second flange 41 which is a flange provided at an end of a second rotating shaft 4 is connected to the rear side of the torque meter 1. The second rotating shaft 4 is rotated by a driving device 6 such as an engine or an electric motor, the first rotating shaft 3 is connected to a load device 5 such as a dynamometer, and the torque measuring device measures the torque acting between the driving device 6 and the load device 5. However, it is also possible to configure the second rotating shaft 4 to be connected to the load device 5, and the first rotating shaft 3 to be rotated by the driving device 6.

[0022] Here, in the measurement system, the torque meter 1 is supported by a first rotating shaft 3 and a second rotating shaft 4 connected to the torque meter 1 so that a portion of the axial direction is located within the hollow of the ring portion 21 and in a non-contact manner with the ring portion 21 of the stator 2.

[0023] The ring portion 21 of the stator 2 forms a one-turn coil that functions both as a power transmission coil for wireless power supply and as a wireless communication antenna, and the stator 2 can transmit power to the torque meter 1 wirelessly and communicate with the torque meter 1 wirelessly.

[0024] FIG. 2 shows the configuration of the torque meter 1. FIG. 2a1 shows a front view of the torque meter 1, FIG. 2a2 shows a side view of the torque meter 1, and FIG. 2a3 shows a rear view of the torque meter 1. As shown in Figures 2a1 and 2a3, the phase angle going from 0 degrees to 360 degrees clockwise as seen from the front is defined, and Figure 2b shows a cross section taken along the cutting line AA at a phase angle of 0 degrees shown in Figure 2a1. Here, where i is an integer from 0 to 7, the cross section taken along the cutting line at a phase angle of 0+(45×i) degrees is the same as Figure 2b.

[0025] Also, Fig. 2c shows a cross-sectional view taken along the cutting line BB at a phase angle of 22.5 degrees shown in Fig. 2a3, where the cross-section taken along the cutting line at a phase angle of 22.5+(45xi) degrees is the same as Fig. 2c. Also, Fig. 2d shows a cross-sectional view taken along line CC at a phase angle of 11.25 degrees shown in Fig. 2a3, where the cross-section taken along the line at a phase angle of 11.25+(45xi) degrees is the same as Fig. 2d. As shown in each figure, the torque meter 1 has a hollow cylindrical strain-flexing part 11, a disk-shaped first disk portion 12 with a central hole and provided in the form of a flange on the front side of the strain-flexing part 11, a disk-shaped second disk portion 13 with a central hole and provided in the form of a flange on the back side of the strain-flexing part 11, and an auxiliary flange 14 provided on the outer peripheral surface of the second disk portion 13.

[0026] In addition, the central portion of the strain-generating part 11 in the axial direction is made thin so that it can be easily deformed, and as shown in Figure 2d, a strain gauge 15 is fixed at a phase angle of 11.25 + (45 × i) degrees in this thin portion.

[0027] The first disk portion 12 has eight bolt holes 121 arranged at equal phase angle intervals along the circumference, and each bolt hole 121 is provided at a position at a phase angle of 0+(45×i) degrees. The second disk portion 13 has eight screw holes 131 arranged at equal phase angle intervals along the circumference, and each screw hole 131 is provided at a position having a phase angle of 22.5+(45×i) degrees. The second disk portion 13 has eight through holes 132 arranged at equal phase angle intervals along the circumference, and each through hole 132 is provided at a position corresponding to a phase angle of 0+(45×i) degrees. A coil 16 is wound around the outer circumferential end of the first disk portion 12, and serves as both a power receiving coil for wireless power supply and a wireless communication antenna. Here, as shown in FIG. 1a, the first disk portion 12 is disposed within the hollow of the ring portion 21 of the stator 2, and the torque meter 1 can wirelessly receive power from the stator 2 via the coil 16 wound around the outer peripheral end of the first disk portion 12, and can communicate with the stator 2 wirelessly.

[0028] The strain gauge 15 detects the strain of the strain-flexing part 11 using power supplied to the coil 16, and the strain detected by the strain gauge 15 is transmitted to the stator 2 via the coil 16 by wireless communication.

[0029] As shown in the side view of Fig. 3a and the rear view of Fig. 3b, an annular gear 17 used for rotation detection can be attached to the torque meter 1 by using the auxiliary flange 14 provided on the outer circumferential surface of the second disk portion 13. When rotation detection is performed using the gear 17, a magnetic sensor 22 that detects magnetic changes caused by the passage of teeth of the gear 17 is provided on the stator 2, and the rotation angle and rotation speed of the torque meter 1 are calculated from the output of the magnetic sensor 22. However, instead of the gear 17, an annular disk with slits arranged in the circumferential direction may be attached to the torque meter 1 by using the auxiliary flange 14, and instead of the magnetic sensor 22, an optical sensor that detects optical changes caused by the passage of the slits may be provided on the stator 2, and the rotation angle and rotation speed of the torque meter 1 may be calculated from the output of the optical sensor.

[0030] Next, the structure of connections between the first rotating shaft 3, the second rotating shaft 4, and the torque meter 1 when configuring the measurement system will be described. As shown diagrammatically in FIG. 4a, a first flange 31 at the end of a first rotating shaft 3 is connected to the front side of the torque meter 1, and a second flange 41 at the end of a second rotating shaft 4 is connected to the rear side of the torque meter 1. The torque meter 1 detects the torque transmitted between the second rotating shaft 4 and the first rotating shaft 3 as a strain in the strain-flexing part 11 using a strain gauge 15.

[0031] The first flange 31 is connected to the torque meter 1 by fastening the first disk portion 12 and the first flange 31 with bolts as shown in the side view of Fig. 4b. The second flange 41 is connected to the torque meter 1 by fastening the second disk portion 13 and the second flange 41 with bolts as shown in the side view of Fig. 4b.

[0032] The first rotating shaft 3 and the second rotating shaft 4 are connected to the torque meter 1 in the following procedure. First, as shown in FIG. 4c1, a bolt is passed through the through hole 132 of the second disk portion 13 and inserted into the bolt hole 121 of the first disk portion 12, and the bolt inserted into the bolt hole 121 is screwed into the connecting screw hole 311 provided in the first flange 31 of the first rotating shaft 3, thereby fastening the first disk portion 12 and the first flange 31.

[0033] Next, as shown in Figure 4c2, the second disk portion 13 and the second flange 41 are fastened together by screwing a bolt inserted into a connecting bolt hole provided in the second flange 41 of the second rotating shaft 4 into the screw hole 131 of the second disk portion 13.

[0034] In this manner, in the torque meter 1 according to this embodiment, both the first flange 31 and the second flange 41 can be fastened to the torque meter 1 from the rear surface side. Next, FIG. 5a1 shows a schematic perspective view of the periphery of bolt hole 121 of first disk portion 12 as viewed from the front side, and FIG. 5a2 shows a schematic cross section of the periphery of bolt hole 121 of first disk portion 12.

[0035] The front end face of first disk portion 12 forms the same plane with the axial direction as the normal line, except for the periphery of bolt hole 121, but as shown in the figure, the periphery of bolt hole 121 protrudes (is convex) slightly toward the front in an annular shape with bolt hole 121 as the central hole, from the plane outside the periphery of bolt hole 121. For example, the shape of the convex portion is such that bolt hole 121 has a diameter of φ19, the height of the portion protruding from the plane around bolt hole 121 is 0.1 mm, and the diameter is φ29.

[0036] On the other hand, the end face of the first flange 31 of the first rotating shaft 3, which faces the front end face of the first disk portion 12, is formed into a flat surface. Therefore, when the first flange 31 is fastened to the first disk portion 12 with bolts, the area of ​​the first disk portion 12 that comes into axial contact with the first flange 31 is only the area around the bolt hole 121, which is shown in gray in Figure 5b.

[0037] Next, FIG. 6a1 shows a schematic perspective view of the periphery of the screw hole 131 of the second disk portion 13 as viewed from the rear side, and FIG. 6a2 shows a schematic cross section of the screw hole 131 of the second disk portion 13. The rear end face of the second disk portion 13 forms the same plane with the axial direction as the normal line, except for the periphery of the screw hole 131, but as shown in the figure, the periphery of the screw hole 131 protrudes (is convex) slightly toward the rear in a circular shape with the screw hole 131 as the central hole from the plane outside the periphery of the screw hole 131. For example, the shape of the convex portion is M18 for the screw hole 131, the height of the portion protruding from the plane around the screw hole 131 is 0.1 mm, and the diameter is φ29.

[0038] As shown in Figs. 6b1 and 6b2, the periphery of the through hole 132 of the second disk portion 13 does not protrude in the rear direction. On the other hand, the end face of the second flange 41 of the second rotating shaft 4 that faces the rear end face of the second disk portion 13 is formed into a flat surface. Therefore, when the second flange 41 is fastened to the second disk portion 13 with bolts, the area of ​​the second disk portion 13 that is in axial contact with the second flange 41 is only the area around the screw hole 131 shown in gray in Figure 6c.

[0039] With such a torque meter 1, the area of ​​the contact region where the first disk portion 12 and the first flange 31 come into axial contact and the area of ​​the contact region where the second disk portion 13 and the second flange 41 come into axial contact can be reduced by concentrating the contact areas only in the area around the bolt.

[0040] The inventors have confirmed through experiments that such a reduction in the contact area reduces the measurement hysteresis of the torque meter 1 and also suppresses changes in the measurement hysteresis due to differences in the thickness and rigidity of the first flange 31 and the second flange 41.

[0041] It is believed that such an effect is obtained for the following reasons. When the entire front end surface of the first disk portion 12 is brought into contact with the first flange 31 as a contact surface and the first disk portion 12 and the first flange 31 are fastened together, if the first flange 31 is deformed by the applied torque and the contact area between the first disk portion 12 and the first flange 31 changes, the stress distribution in the first flange 31 changes so that the stress is concentrated on the contact surface as the contact area decreases. Since the deformation of the first flange 31 depends on the magnitude of the applied torque, the stress distribution in the first flange 31 also changes according to the magnitude of the applied torque. Furthermore, since the stress is generated as a force against the torque, the stress changes in the opposite directions when the torque increases and when it decreases.

[0042] Such changes in the stress distribution and the direction of the stress change in the first flange 31 due to changes in the contact area between the first disk portion 12 and the first flange 31 in response to the applied torque cause hysteresis in the measurement of the strain gauge 15.

[0043] On the other hand, in the torque meter 1 of this embodiment, the contact points between the first disk portion 12 and the first flange 31 are concentrated only around the bolt, and the contact area is also small. Therefore, the change in the contact area between the first disk portion 12 and the first flange 31 due to the change in the applied torque is small, and the difference in this change due to differences in the thickness and rigidity of the first flange 31 is also small.

[0044] As a result, the measurement hysteresis of the torque meter 1 can be kept small, and changes in the measurement hysteresis due to differences in the thickness and rigidity of the first flange 31 can be suppressed.

[0045] The same is true for the second disk portion 13 and the second flange 41; the hysteresis can be kept small, and changes in the hysteresis of the torque meter 1 due to differences in the thickness and rigidity of the second flange 41 can be kept small.

[0046] Furthermore, the inventors have confirmed through experiments that the reduction in the contact area as described above also suppresses changes in sensitivity of the torque meter 1 caused by differences in the thickness and rigidity of the first flange 31 and the second flange 41.

[0047] It is believed that such an effect is obtained for the following reasons. When the first disk portion 12 and the first flange 31 are fastened together with the entire front end surface of the first disk portion 12 abutting against the first flange 31 as a contact surface, the stress distribution of the contact surface of the first disk portion 12 in the fastened state changes depending on the thickness and rigidity of the first flange 31, and the torque transmission path between the first disk portion 12 and the first flange 31 becomes different. Therefore, depending on the thickness and rigidity of the first flange 31, the stress distribution of the strain-generating portion 11 when torque is applied and the type of strain generated become different, and different strains are detected by the strain gauge 15. As a result, the sensitivity of the torque meter 1 becomes different depending on the thickness and rigidity of the first flange 31.

[0048] On the other hand, in the torque meter 1 of this embodiment, the contact points between the first disk portion 12 and the first flange 31 are concentrated only around the bolt, and the contact area is also small. Therefore, even if the thickness and rigidity of the first flange 31 are different, the change in stress distribution on the contact surface of the first disk portion 12 in the fastened state is small, and as a result, the change in sensitivity of the torque meter 1 due to the difference in thickness and rigidity of the first flange 31 can be suppressed to a small value.

[0049] The same is true for the second disk portion 13 and the second flange 41, and the change in sensitivity of the torque meter 1 due to differences in the thickness and rigidity of the second flange 41 can be suppressed to a small value. The embodiment of the present invention has been described above. In the above embodiment, the periphery of the bolt hole 121 on the front end face of the first disk portion 12 is protruded in the front direction so that the area in which the first disk portion 12 and the first flange 31 of the first rotating shaft 3 contact in the axial direction is limited to the area around the bolt hole 121. However, the front end face of the first disk portion 12 may be formed flat without protruding the periphery of the bolt hole 121 on the front end face, and instead, as shown in the schematic oblique view of the first rotating shaft 3 and the first flange 31 in Figure 7a1 and the schematic oblique view of the area around the connecting screw hole 311 of the first flange 31 in Figure 7a2, the area in which the first disk portion 12 and the first flange 31 of the first rotating shaft 3 contact in the axial direction may be limited to the area around the bolt.

[0050] In addition, in the above embodiment, the periphery of the screw hole 131 on the rear end face of the second disk portion 13 is protruded toward the rear, so that the area in which the second disk portion 13 and the second flange 41 of the second rotating shaft 4 contact in the axial direction is limited to the area around the screw hole 131. However, this may be achieved by forming the rear end face as a flat surface without protruding the periphery of the screw hole 131 on the rear end face of the second disk portion 13, and instead, by slightly protruding the periphery of the connecting bolt hole of the second flange 41 of the second rotating shaft 4 in the front direction, as shown in the schematic oblique view of the second rotating shaft 4 and the second flange 41 in Figure 7b1 and the schematic oblique view of the periphery of the connecting bolt hole of the second flange 41 in Figure 7b2, so that the area in which the second disk portion 13 and the second flange 41 of the second rotating shaft 4 contact in the axial direction is limited to the area around the bolt.

[0051] In addition, in another embodiment, the front end face of the first disk portion 12 may be formed flat without protruding the periphery of the bolt hole 121 on the front end face, and instead, a circular ring member may be used as a washer for the bolt used to connect the first disk portion 12 and the first flange 31 of the first rotating shaft 3.

[0052] In this case, as shown in the schematic diagram of Figure 8a1 and the cross-sectional view of Figure 8a2, the bolt used to connect the first disk portion 12 and the first flange 31 is passed through the central hole of the circular member 7 between the front end face of the first disk portion 12 and the first flange 31, and screwed into the connecting screw hole 311 of the first flange 31.

[0053] As shown in Figure 8a2, where the circular ring member 7 is painted black, even when the circular ring member 7 is used in this manner, the area of ​​axial contact between the first disk portion 12 and the first flange 31 can be limited to the area around the bolt, thereby reducing the contact area between the first disk portion 12 and the first flange 31.

[0054] Similarly, the rear end face of the second disc portion 13 may be formed flat without protruding the periphery of the screw hole 131 thereon, and instead the annular member 7 may be used as a washer for the bolt used to connect the second disc portion 13 and the second flange 41 of the second rotating shaft 4.

[0055] In this case, as shown in Figures 8b1 and 8b2, the bolt used to connect the second disc portion 13 and the second flange 41 is passed through the central hole of the circular member 7 between the rear end face of the second disc portion 13 and the second flange 41 and screwed into the screw hole 131 of the second disc portion 13.

[0056] As shown in Figure 8b2, where the circular ring member 7 is painted black, even when the circular ring member 7 is used in this manner, the area of ​​axial contact between the second disk portion 13 and the second flange 41 can be limited to the area around the bolt, thereby reducing the contact area between the second disk portion 13 and the second flange 41.

[0057] In the above embodiment, the first disk portion 12 and the first flange 31 are configured to contact only around the bolt hole 121, but as long as the area of ​​axial contact is limited to the area around the bolt hole 121, there may be an area other than the area around the bolt hole 121 where the first disk portion 12 and the first flange 31 contact.

[0058] The area where the first disk portion 12 and the first flange 31 contact each other other than around the bolt hole 121 may be an area where the first disk portion 12 and the first flange 31 contact each other in the radial direction in a structure provided for centering the first disk portion 12 and the first flange 31.

[0059] Similarly, the second disk portion 13 and the second flange 41 are configured to contact only around the screw hole 131, but as long as the area of ​​axial contact is limited to the area around the screw hole 131, there may be areas other than the area around the screw hole 131 where the second disk portion 13 and the second flange 41 contact.

[0060] The area where the second disc portion 13 and the second flange 41 contact each other other than around the screw hole 131 may be an area where the second disc portion 13 and the second flange 41 contact each other in the radial direction in a structure provided for centering the second disc portion 13 and the second flange 41.

[0061] For example, as shown in the rear view of FIG. 9a1 and the oblique view seen from the rear direction of FIG. 9a2, a ring-shaped protrusion 81 protruding in the rear direction may be provided around the central hole of the second disk portion 13, as shown in FIG. 9b1, a circular protrusion 82 that fits into the central hole of the first disk portion 12, and as shown in FIG. 9b2, a circular recess 83 that fits into the protrusion 81 of the second disk portion 13 may be provided in the second flange 41. As shown in the cross-sectional view of FIG. 9c, the first flange 31 and the first disk portion 12 are loosely fitted together with the protrusion 82 of the first flange 31 inserted into the central hole of the first disk portion 12, and the second flange 41 and the second disk portion 13 are loosely fitted together with the protrusion 81 of the second disk portion 13 inserted into the recess 83 of the second flange 41.

[0062] However, the shape of the convex portion 82 of the first flange 31 is set so that the first flange 31 and the first disc portion 12 do not come into contact in the axial direction when they are fastened, and the shapes of the protruding portion 81 of the second disc portion 13 and the concave portion 83 of the second flange 41 are set so that the second flange 41 and the second disc portion 13 do not come into contact in the axial direction when they are fastened. [Explanation of symbols]

[0063] Reference Signs List: 1...torque meter, 2...stator, 3...first rotating shaft, 4...second rotating shaft, 5...load device, 6...drive device, 7...ring member, 9...torque meter, 11...strain-flexing portion, 12...first disk portion, 13...second disk portion, 14...auxiliary flange, 15...strain gauge, 16...coil, 17...gear, 21...ring portion, 22...magnetic sensor, 31...first flange, 41...second flange, 81...projecting portion, 82...convex portion, 83...concave portion, 91...hollow body portion, 92...drive side flange portion, 93...load side flange portion, 121...bolt hole, 131...screw hole, 132...through hole, 311...connecting screw hole.

Claims

1. A measurement system comprising a first rotating shaft, a second rotating shaft, and a torque meter for detecting a torque transmitted between the first rotating shaft and the second rotating shaft, The torque meter includes a first disk portion, a second disk portion, a strain generating portion connecting the first disk portion and the second disk portion, and a strain detection means for detecting a strain generated in the strain generating portion, A first flange is provided at an end of the first rotating shaft, the first flange being a flange connected to the first disk portion by a bolt, The end of the second rotating shaft is provided with a second flange which is a flange connected to the second disk portion by a bolt. A measurement system characterized in that at least a portion of the area around a bolt hole or screw hole through which a bolt connecting the first disk portion is inserted on the surface of the first flange facing the first disk portion has a shape that protrudes toward the first disk portion so that the only point where the first flange and the first disk portion abut in the axial direction is the said portion.

2. The measurement system according to claim 1, A measurement system characterized in that at least a portion of the area around a bolt hole or screw hole through which a bolt connecting the second disk portion is inserted on the surface of the second flange facing the second disk portion has a shape that protrudes toward the second disk portion so that the only point where the second flange and the second disk portion abut in the axial direction is the said portion.

3. A measurement system comprising a first rotating shaft, a second rotating shaft, and a torque meter for detecting a torque transmitted between the first rotating shaft and the second rotating shaft, The torque meter includes a first disk portion, a second disk portion, a strain generating portion connecting the first disk portion and the second disk portion, and a strain detection means for detecting a strain generated in the strain generating portion, a first flange is provided at an end of the first rotating shaft, the first flange being a flange connected to the first disk portion by a bolt; The end of the second rotating shaft is provided with a second flange which is a flange connected to the second disk portion by a bolt. The measurement system includes a first annular member that is an annular member having a hole; the first annular member is disposed between the first flange and the first disk portion such that the first flange and the first disk portion do not directly contact each other in the axial direction, a bolt connecting the first flange and the first disk portion being passed through a hole in the first annular member between the first flange and the first disk portion, thereby connecting the first flange and the first disk portion.

4. The measurement system according to claim 3, a second annular member that is an annular member having a hole; the second annular member is disposed between the second flange and the second disk portion such that the second flange and the second disk portion do not directly contact each other in the axial direction, A measurement system characterized in that the bolt connecting the second flange and the second disk portion is passed through a hole in the second annular member between the second flange and the second disk portion, connecting the second flange and the second disk portion.

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