Sealing structure of torque sensor and robot

Abstract

A sealing structure for a torque sensor is fixed between a fixed part of a speed reducer and a first member, the speed reducer is provided with the fixed part and a movable part, the movable part is supported so as to be rotatable about a predetermined axis with respect to the fixed part, and the torque sensor detects a torque about the axis. The sealing structure of the torque sensor is provided with an annular sealing member surrounding the outer periphery of the torque sensor, and the sealing member is compressed in the axial direction by the fixing portion and the first member.

Description

Technical Field

[0001] The present disclosure relates to a support structure of a torque sensor and a robot. Background Art

[0002] Conventionally, there is known a torque detection device in which a sealing member is arranged between housings surrounding a torque sensor (for example, see Patent Document 1). In this device, an annular sealing member is compressed by using one housing that accommodates a reducer and another housing that fixes the torque sensor between the reducer and the output shaft.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2022-52789 Summary of the invention

[0006] Problem that the invention aims to solve

[0007] However, one housing rotates relative to the other housing around the axis of the reducer. Therefore, there is a disadvantage that the sealing resistance generated between the two housings acts on the torque sensor, resulting in a decrease in the detection accuracy of the torque sensor. Therefore, it is desirable to seal the torque sensor without reducing the detection accuracy.

[0008] Solutions for solving problems

[0009] One embodiment of the present invention is a sealing structure of a torque sensor, wherein the sealing structure of the torque sensor is fixed between a fixed part and a first component of a reducer, wherein the reducer comprises the fixed part and a movable part, wherein the movable part is supported to be rotatable around a predetermined axis relative to the fixed part, and wherein the torque sensor detects torque around the axis. The sealing structure of the torque sensor comprises an annular sealing component surrounding the outer circumference of the torque sensor, wherein the sealing component is compressed along the axial direction by the fixed part and the first component. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a partial longitudinal sectional view showing the robot according to the first embodiment of the present disclosure.

[0011] Figure 2 Yes Figure 1 A partially enlarged longitudinal sectional view illustrating the sealing structure of a torque sensor of a robot.

[0012] Figure 3 yes Figure 1 An exploded longitudinal cross-sectional view of the robot's reducer, torque sensor, and O-ring.

[0013] Figure 4 Yes means Figure 3 An exploded longitudinal sectional view of the reducer, torque sensor, O-ring assembly and the first component.

[0014] Figure 5 is Figure 2 A partially enlarged longitudinal sectional view illustrating the assembly of a reducer, a torque sensor, and a first component in a sealing structure of a torque sensor.

[0015] Figure 6 Yes means Figure 5 A partially enlarged longitudinal sectional view of a state where the torque sensor is started to be fitted into the recessed portion of the first component.

[0016] Figure 7 Yes means Figure 5 A partially enlarged longitudinal sectional view of the state in which the recessed portion and the torque sensor are fitted together.

[0017] Figure 8 It means that Figure 4 A longitudinal sectional view of a state where the assembly is assembled with the first component.

[0018] Fig. 9 1 is a partial longitudinal sectional view of a robot according to a second embodiment of the present disclosure.

[0019] Fig.10 Yes Fig. 9 A partially enlarged longitudinal sectional view illustrating the sealing structure of a torque sensor of a robot.

[0020] Fig.11 Yes means Fig. 9 An exploded longitudinal sectional view of a reducer, a torque sensor, an O-ring assembly, an adapter, an O-ring, and a base of a robot.

[0021] Fig.12 is Fig.10 A partial enlarged longitudinal sectional view illustrating the assembly of the torque sensor and the adapter in the sealing structure of the torque sensor.

[0022] Fig.13 Yes means Fig.12 A partially enlarged longitudinal sectional view of a state where the torque sensor is initially engaged with the recessed portion of the adapter.

[0023] Fig.14 Yes means Fig.12 A partially enlarged longitudinal sectional view of the state in which the recessed portion of the adapter and the torque sensor are fitted together.

[0024] Fig.15 It means that Fig.11A longitudinal sectional view of the assembled body, adapter, O-ring and base. DETAILED DESCRIPTION

[0025] Hereinafter, a sealing structure of a torque sensor 5 and a robot 1 according to a first embodiment of the present disclosure will be described with reference to the drawings.

[0026] The robot 1 of this embodiment is, for example, a vertical multi-joint robot. Figure 1 As shown, the robot 1 includes a first member 2 and a second member 3 at any joint, and the second member 3 is supported so as to be rotatable around a first axis (axis) A relative to the first member 2 .

[0027] The first component 2 has a cylindrical shape and has openings 2a and 2b opened on both sides in the direction of the first axis A. The first component 2 has a partition wall 2c that partitions the internal space in the direction along the first axis A. A speed reducer 4 is arranged between the first component 2 and the second component 3, and the speed reducer 4 drives the second component 3 to rotate around the first axis A relative to the first component 2.

[0028] In addition, a torque sensor 5 is fixed between the speed reducer 4 and the first member 2. The torque sensor 5 detects torque about the first axis A.

[0029] The speed reducer 4 is formed in a cylindrical shape and includes a housing (fixed portion) 8 and an output portion (movable portion) 7 supported rotatably relative to the housing 8 about a first axis A. The torque sensor 5 is fixed between the housing 8 of the speed reducer 4 and the partition wall 2 c of the first member 2 .

[0030] The torque sensor 5 is formed in a disk shape with a smaller outer diameter than the reducer 4. The torque sensor 5 includes an annular first portion 9 disposed radially inwardly and an annular second portion 10 disposed radially outwardly. In addition, the torque sensor 5 includes a third portion 11 connecting the first portion 9 and the second portion 10.

[0031] A sensor such as a strain gauge (not shown) for detecting torque by strain is disposed on the third portion 11. The sensor may be disposed near either the first portion 9 or the second portion 10, or may be disposed at an equal distance.

[0032] The first portion 9 of the torque sensor 5 has a plurality of through holes 9a extending in the plate thickness direction at intervals in the circumferential direction around the first axis A. The torque sensor 5 also has a circular recess 5c centered on the first axis A on one end surface 5d of the first portion 9 .

[0033] On the other hand, the housing 8 of the speed reducer 4 includes a convex portion 8b and an end surface 8c, the convex portion 8b is fitted with the concave portion 5c of the torque sensor 5, and the end surface 8c is in close contact with the end surface 5d of the torque sensor 5. The convex portion 8b of the housing 8 and the concave portion 5c of the torque sensor 5 are fitted with an extremely short fitting length, for example, 1 to 2 mm.

[0034] The bolt 12 passing through the through hole 9a is fastened to the threaded hole 8a while the convex portion 8b is fitted into the concave portion 5c and the end face 8c is in close contact with the end face 5d. Thus, the torque sensor 5 is fixed to the reducer 4. In addition, a plurality of threaded holes 10a penetrating in the plate thickness direction are provided at intervals in the circumferential direction around the first axis A on the second portion 10 of the torque sensor 5.

[0035] The first member 2 includes a fitting portion 16, which is formed of a circular recessed portion into which the outer peripheral surface 5a of the torque sensor 5 fits. Figure 2 As shown, the fitting portion (recess) 16 has an inner peripheral surface 16a which is arranged radially outward with a gap relative to the outer peripheral surface 5a of the torque sensor 5. In addition, the fitting portion 16 has a bottom surface 16b which abuts against the end surface 5b of the second portion 10 of the torque sensor 5 in the thickness direction.

[0036] The fitting portion 16 includes a concave portion 16c, and when the end face 5b of the torque sensor 5 abuts against the bottom face 16b, only one end of the outer peripheral surface 5a is fitted into the concave portion 16c. The fitting length of the concave portion 16c is set to be slightly larger than the appropriate compression amount of the O-ring 17 described later, but is preferably as short as possible. For example, when the appropriate compression amount of the O-ring 17 is 0.7 mm, the fitting length of the concave portion 16c is preferably greater than 0.7 mm and less than 2 mm.

[0037] The first member 2 has a plurality of through holes 2e opened on the bottom surface 16b of the fitting portion 16 at intervals in the circumferential direction around the first axis A. The through holes 2e are provided at positions that coincide with the screw holes 10a when the outer peripheral surface 5a of the torque sensor 5 is fitted into the fitting portion 16.

[0038] The bolt 13 that has passed through the through hole 2e of the first member 2 is fastened to the screw hole 10a of the torque sensor 5. Thus, the torque sensor 5 can be fixed to the first member 2 by the bolt 13.

[0039] like Figure 2 As shown, the first component 2 has an end face (plane) 2f extending in a direction perpendicular to the first axis A radially outward of the torque sensor 5. In addition, the end face (plane) 8c of the housing 8 faces the end face 2f of the first component 2 in the direction of the first axis A with a gap therebetween.

[0040] An O-ring (sealing member) 17 is disposed between the end surface 2f of the first member 2 and the end surface 8c of the housing 8. The gap between the end surface 2f of the first member 2 and the end surface 8c of the housing 8 has a size that allows the O-ring 17 to be crushed by an appropriate amount of compression.

[0041] The compression amount is the difference between the linear diameter of the O-ring 17 when it is not compressed and when it is compressed in the direction of the first axis A. The O-ring 17 is compressed with an appropriate amount of compression to seal the gap so as to prevent liquid and gas from passing through.

[0042] The O-ring 17 is formed into a ring shape surrounding the torque sensor 5 and, for example, Figure 4 As shown in FIG. 1 , in the unflattened state, the inner diameter dimension is greater than or equal to the outer diameter dimension of the outer peripheral surface 5a of the torque sensor 5. Figure 2 As shown, the O-ring 17 has an inner diameter dimension that does not contact or lightly contacts the outer peripheral surface 5 a of the torque sensor 5 when it is compressed.

[0043] Thus, the O-ring 17 is disposed at the edge (opening edge) around the fitting portion 16. The O-ring 17 seals the gap between the end surfaces 2f and 8c that contact the O-ring 17 from both sides in the first axis A direction.

[0044] The first component 2, the torque sensor 5, and the speed reducer 4 include a hollow hole 19, and the hollow hole 19 communicates from the first component 2 to the inside of the rotating body 3 in a space including the first axis A. Through the hollow hole 19, a linear body (not shown) introduced from one side of the partition wall 2c of the first component 2 can be wired to the second component 3 side.

[0045] Hereinafter, the sealing structure of the torque sensor 5 and the operation of the robot 1 according to the present embodiment configured in this manner will be described.

[0046] The robot 1 of the present embodiment is assembled as follows.

[0047] First, if Figure 3 As shown in the figure, the reducer 4 is arranged so that the housing 8 is at the top and the first axis A is in the vertical direction. Then, the torque sensor 5 is brought close from the top of the reducer 4. The convex portion 8b of the housing 8 is fitted into the concave portion 5c of the torque sensor 5, and the end face 5d of the torque sensor 5 is brought into close contact with the end face 8c of the housing 8.

[0048] In this state, the phase of the through hole 9a of the first part 9 of the torque sensor 5 is aligned with the phase of the threaded hole 8a of the housing 8. Figure 4As shown, the bolt 12 passing through the through hole 9a of the first portion 9 of the torque sensor 5 is fastened to the threaded hole 8a of the housing 8. Thus, the torque sensor 5 is fixed to the housing 8 of the speed reducer 4 in a state where the first axis A direction and the direction perpendicular to the first axis A are mutually positioned.

[0049] Next, an O-ring 17 is hung around the outer circumference of the torque sensor 5 fixed to the reducer 4 and arranged on the end surface 8c of the housing 8 radially outward of the outer circumferential surface 5a. Figure 4 As shown, the first component 2 is lowered from above the torque sensor 5 .

[0050] like Figure 5 As shown in FIG. 1 , the torque sensor 5 is inserted into the fitting portion 16 of the first component 2. Figure 6 As shown, the outer peripheral surface 5 a of the torque sensor 5 is fitted into the recessed portion 16 c near the bottom surface 16 b of the fitting portion 16 .

[0051] In this case, according to the present embodiment, the fitting length of the torque sensor 5 to the recessed portion 16c is set to be slightly larger than the appropriate compression amount of the O-ring 17. Figure 6 As shown, the torque sensor 5 is fitted into the recessed portion 16 c before the first member 2 and the O-ring 17 come into contact with each other.

[0052] If the first component 2 and the O-ring 17 are brought into contact before the engagement is started, the operator cannot recognize the start of the engagement by touch, which reduces the workability of the assembly operation. In contrast, by bringing the first component 2 into contact with the O-ring 17 after the engagement is started, the operator can more reliably recognize the start of the engagement. Therefore, the workability of the assembly operation is improved.

[0053] Then, if Figure 7 As shown, the outer peripheral surface 5a of the torque sensor 5 is fitted into the recessed portion 16c. By bringing the bottom surface 16b of the fitting portion 16 of the first member 2 into close contact with the end surface 5b of the torque sensor 5, the O-ring 17 is compressed by an appropriate amount.

[0054] In this state, the phases of the through hole 6a of the first component 2 and the threaded hole 10a of the torque sensor 5 are aligned. Figure 8 As shown, the bolt 13 passing through the through hole 2 e of the first component 2 is fastened to the threaded hole 10 a of the torque sensor 5 .

[0055] The torque sensor 5 is fixed to the first member 2 by tightening the bolts 13. The torque sensor 5 and the first member 2 are fixed in the direction of the first axis A and in a direction perpendicular to the first axis A so as to be positioned relative to each other.

[0056] When the bolt 13 is tightened, the gap between the housing 8 and the first component 2 becomes equal to the size of the O-ring 17 after being compressed by an appropriate amount. As a result, the gap between the housing 8 and the first component 2 is sealed by the O-ring 17 over the entire circumference of the torque sensor 5 radially outward.

[0057] According to this embodiment, the outer peripheral surface 5a of the torque sensor 5 is fitted with the first component 2 by the recessed portion 16c having a sufficiently short fitting length. By fitting the outer peripheral surface 5a of the torque sensor 5 with the recessed portion 16c, the center of the torque sensor 5 can be aligned with the center of the first component 2 with high accuracy.

[0058] In addition, by reducing the fitting length of the recessed portion 16c, it is possible to prevent the force or moment from the first member 2 from acting on the outer peripheral surface 5a of the torque sensor 5. In other words, it is possible to prevent the force or moment acting on the outer peripheral surface 5a of the torque sensor 5 from being detected as torque by the torque sensor 5. Thus, it is possible to prevent the torque detection accuracy of the torque sensor 5 from being reduced.

[0059] Furthermore, the gap between the housing 8 of the speed reducer 4 and the first member 2 is sealed by an O-ring 17 radially outward from the torque sensor 5. This prevents liquid that has entered from the outside through the gap between the first member 2 and the second member 3 from entering the torque sensor 5 side.

[0060] As a method of preventing the liquid from entering through the gap between the first component 2 and the second component 3, there is also a method of sealing the cylindrical gap between the reducer 4 and the first component 2. However, in this case, during the operation of fitting the torque sensor 5 to the first component 2, the sliding resistance of the O-ring that is compressed between the reducer 4 and the base 2 acts.

[0061] Therefore, the operator may not be able to recognize the start of the fitting by touch. In addition, there may be a problem that the fitting surface is damaged or the assembly is tilted due to tightening the bolt 13 in an inaccurately fitted state.

[0062] According to the present embodiment, the O-ring 17 is compressed between the end faces 2f and 8c that are orthogonal to the first axis A. Thus, the sliding resistance of the O-ring 17 does not work in the operation of fitting the outer peripheral surface 5a of the torque sensor 5 into the recessed portion 14 of the first member 2. Therefore, the operator can easily recognize the start of fitting by touch, and can perform assembly correctly.

[0063] In the present embodiment, the O-ring 17 between the housing 8 and the first member 2 is crushed radially outward of the torque sensor 5. The crushed O-ring 17 does not contact the outer peripheral surface 5a of the torque sensor 5 or contacts only lightly.

[0064] Therefore, no force or moment acts on the torque sensor 5 via the O-ring 17. Thus, it is possible to prevent the torque sensor 5 from detecting the force or moment acting on the torque sensor 5 via the O-ring 17 as torque.

[0065] In addition, in this embodiment, a vertical articulated robot is exemplified as the robot 1. Alternatively, it is also possible to apply to a robot 1 of any other form.

[0066] In addition, in the present embodiment, the sealing structure of the torque sensor 5 provided between the first member 2 and the second member 3 is exemplified.

[0067] For example, a rotating body may be used as the first member 2, and for example, a first arm may be used as the second member 3. Alternatively, the same structure may be adopted as a sealing structure of a torque sensor disposed between a speed reducer of another joint shaft and the first member.

[0068] Furthermore, although the O-ring 17 is used as the sealing member, any other sealing member such as an annular gasket may be used instead.

[0069] In the present embodiment, the radial position of the O-ring 17 is roughly guided by the outer peripheral surface 5a of the torque sensor 5. Alternatively, an O-ring groove may be formed in the housing 8 or the first member 2 to define the radial position of the O-ring 17.

[0070] According to the present disclosure, the torque sensor 5 can be used to accurately detect the torque acting on the first member 2 from the speed reducer 4. In addition, according to the robot 1 of the present disclosure, the torque sensor 5 capable of detecting the torque with high accuracy can perform force control with high accuracy.

[0071] Next, a sealing structure of a torque sensor 5 and a robot 1 according to a second embodiment of the present disclosure will be described below with reference to the drawings.

[0072] In the description of this embodiment, the same reference numerals are given to the same components as those of the first embodiment, and the description thereof will be omitted.

[0073] In the first embodiment, the case where the torque sensor 5 is directly fixed to the first component 2 is exemplified. Fig. 9 As shown, the case where the torque sensor 5 is fixed to the first member 2 via the adapter 6 will be described. In this embodiment, the first member 2 is a base, and the second member 3 is a rotating body. Hereinafter, they are also referred to as the base 2 and the rotating body 3.

[0074] Preferably, the adapter 6 is made of a material having higher rigidity than the material constituting the base 2 and is in a large disk shape radially outward from the torque sensor 5. When the base 2 is made of, for example, an aluminum alloy, the adapter 6 is preferably made of, for example, iron.

[0075] The adapter 6 is provided with a plurality of through holes 6a extending through the adapter 6 in the plate thickness direction at intervals in the circumferential direction. The adapter 6 is fixed to the torque sensor 5 by fastening bolts 13 passing through the through holes 6a to the threaded holes 10a of the second portion 10 .

[0076] In addition, the adapter 6 has an outer diameter dimension that is sufficiently larger than the outer diameter of the torque sensor 5. That is, the adapter 6 extends further radially outward beyond the outer peripheral surface 5a of the torque sensor 5. Fig. 9 In the example shown, the outer diameter of the adapter 6 is identical to the outer diameter of the reducer 4 .

[0077] Also, the adapter 6 has a size that covers the entire radial area of ​​the torque sensor 5 .

[0078] That is, the adapter 6 has a size that extends radially inward of the second portion 10 required for fixing the torque sensor 5. In addition, the adapter 6 has a thickness dimension that is sufficiently larger than the thickness of the torque sensor 5. Thus, the adapter 6 ensures sufficient rigidity required to suppress deformation of the first component 2.

[0079] The adapter 6 includes a first fitting portion 15 formed of a circular convex portion, and the first fitting portion 15 is fitted with a circular concave portion 14 provided on the first member 2 with the first axis A as the center. In the present embodiment, a fitting portion (hereinafter referred to as a second fitting portion) 16 is provided on the adapter 6. The outer diameter of the convex portion constituting the first fitting portion 15 and the inner diameter of the concave portion constituting the second fitting portion 16 are set to be substantially equal.

[0080] Furthermore, when the outer peripheral surface 5 a of the torque sensor 5 is fitted into the second fitting portion 16 , the through hole 6 a is provided at a position that coincides with the screw hole 10 a .

[0081] Furthermore, when the first fitting portion 15 of the adapter 6 is fitted into the recessed portion 14 , the through hole 2 e of the base 2 is provided at a position that coincides with the through hole 6 a .

[0082] The bolts 13 passing through the through holes 2e of the base 2 and the through holes 6a of the adapter 6 are fastened to the threaded holes 10a of the torque sensor 5. Thus, the torque sensor 5 and the adapter 6 can be fixed to the base 2 by fastening the bolts 13 together.

[0083] The outer portion of the adapter 6, which is radially outward of the torque sensor 5, has parallel end faces (planes) 6b and 6c on both sides in the thickness direction and are perpendicular to the thickness direction. Fig.10 As shown, the end face 2f of the base 2 and the end face 6b of the adapter 6 face each other with a gap in the direction of the first axis A. In addition, the end face 8c of the housing 8 of the speed reducer 4 and the end face 6c of the adapter 6 face each other with a gap in the direction of the first axis A.

[0084] The O-ring (second sealing member) 18 is formed in an annular shape surrounding the first fitting portion 15 and is arranged between the end surface 2f of the base 2 and the end surface 6b of the adapter 6. In addition, an O-ring 17 is arranged between the end surface 8c of the housing 8 of the speed reducer 4 and the end surface 6c of the adapter 6.

[0085] The gap between the end face 2f of the base 2 and the end face 6b of the adapter 6 has a size that can compress the O-ring 18 with an appropriate amount of compression. In addition, the gap between the flat surface 8c of the housing 8 and the flat surface 6c of the adapter 6 has a size that can compress the O-ring 17 with an appropriate amount of compression.

[0086] The O-rings 17 and 18 are compressed by an appropriate amount to seal the gap so as to prevent liquid and gas from passing through.

[0087] The O-ring 17 seals the gap between the flat surfaces 6c and 8c in contact with the O-ring 17 from both sides in the direction of the first axis A. The O-ring 18 is compressed along the axis A direction between the end surfaces 2f and 6b in contact with the O-ring 18 from both sides in the direction of the first axis A to seal the gap.

[0088] The adapter 6 also includes a hollow hole 19 , and the hollow hole 19 communicates in a space including the first axis A from the base 2 to the interior of the rotating body 3 .

[0089] Hereinafter, the sealing structure of the torque sensor 5 and the operation of the robot 1 according to the present embodiment configured in this manner will be described.

[0090] The robot 1 of the present embodiment is assembled as follows.

[0091] First, the assembly process up to the speed reducer 4 , the torque sensor 5 , and the O-ring 17 is the same as that of the first embodiment.

[0092] When the O-ring 17 is assembled, Fig.11 As shown in FIG. 5 , the adapter 6 is lowered from above the torque sensor 5. Fig.12 As shown in FIG. 1 , the torque sensor 5 is inserted into the second fitting portion 16 of the adapter 6. Then, as shown in FIG. Fig.13 As shown, the outer peripheral surface 5 a of the torque sensor 5 is fitted into the recessed portion 16 c near the bottom surface 16 b of the second fitting portion 16 .

[0093] In this embodiment, the fitting length of the torque sensor 5 to the recessed portion 16c is also set to be slightly larger than the appropriate compression amount of the O-ring 17. Fig.13 As shown, the torque sensor 5 is fitted into the recessed portion 16 c starting before the adapter 6 comes into contact with the O-ring 17 .

[0094] By bringing the adapter 6 into contact with the O-ring 17 after the start of fitting, the operator can more reliably recognize the start of fitting, thereby improving the workability of the assembly work.

[0095] Then, if Fig.14 As shown, the outer peripheral surface 5a of the torque sensor 5 is fitted into the recessed portion 16c. The bottom surface 16b of the second fitting portion 16 of the adapter 6 is brought into close contact with the end surface 5b of the torque sensor 5, so that the O-ring 17 is compressed with an appropriate amount of compression. In this state, the through hole 6a of the adapter 6 and the threaded hole 10a of the torque sensor 5 are aligned in phase.

[0096] In addition, in this state, if Fig.14 As shown in FIG. 1 , an O-ring 18 is disposed on the radially outer end surface 6 b of the first fitting portion 15 of the adapter 6. Fig.11 As shown, the base 2 is brought closer to the adapter 6 from above, and the first fitting portion 15 of the adapter 6 is fitted into the recess 14 of the base 2 .

[0097] When the bottom surface of the recessed portion 14 of the base 2 is in close contact with the end surface of the adapter 6, the phases of the through hole 2e of the base 2 and the through hole 6a of the adapter 6 are aligned. Fig.15 As shown, the bolts 13 passing through the through holes 2 e and 6 a of the base 2 and the adapter 6 are fastened to the threaded holes 10 a of the torque sensor 5 .

[0098] The torque sensor 5 and the adapter 6 are fastened together and fixed to the base 2 by the tightening bolts 13. The torque sensor 5, the adapter 6, and the base 2 are fixed in a state in which they are positioned relative to each other in the first axis A direction and in a direction perpendicular to the first axis A.

[0099] By fastening the bolts 13 together, the torque sensor 5 and the adapter 6, as well as the adapter 6 and the base 2, can be fixed at the same distance in the radial direction. Compared with a case where the fixing distances are different in the radial direction, the torque sensor 5 can be less susceptible to the influence of the moment generated around the axis orthogonal to the first axis A.

[0100] Furthermore, by fastening together, countersinking of the adapter 6, which is required when the adapter 6 is separately fixed to the torque sensor 5 and the base 2, is not required. This can prevent the rigidity of the adapter 6 from being reduced and prevent the adapter 6 from being larger than necessary.

[0101] When the fastening is completed, the gaps between the housing 8 and the adapter 6, and between the base 2 and the adapter 6, are equal to the size after the O-rings 17 and 18 are flattened by an appropriate amount of compression. As a result, the gap between the housing 8 of the speed reducer 4 and the adapter 6 is sealed by the O-ring 17 over the entire circumference on the radially outer side of the torque sensor 5. In addition, the gap between the base 2 and the adapter 6 is also sealed by the O-ring 18 over the entire circumference on the radially outer side of the first fitting portion 15 of the adapter 6.

[0102] Thus, according to the present embodiment, the torque sensor 5 is fixed to the base 2 via the adapter 6. Moreover, the adapter 6 is made of a material having higher rigidity than the base 2. Furthermore, the adapter 6 is thick and has a shape that widely extends not only in the second portion 10 of the torque sensor 5 to which it is fixed, but also in the radially inner and outer directions of the second portion 10.

[0103] Thus, the adapter 6 has sufficiently high rigidity, and can sufficiently suppress deformation of the base 2 at the bottom surface of the recess 14 to which the adapter 6 is fixed. That is, it is possible to suppress deformation of the base 2 caused by the force or torque applied from the speed reducer 4 side to the torque sensor 5, and improve the detection accuracy of the torque sensor 5.

[0104] In addition, according to the present embodiment, the outer peripheral surface 5a of the torque sensor 5 is fitted with the adapter 6 by the recessed portion 16c having a sufficiently small fitting length. By fitting the outer peripheral surface 5a of the torque sensor 5 with the recessed portion 16c, the center of the torque sensor 5 and the center of the adapter 6 can be aligned with high precision.

[0105] In addition, by reducing the fitting length of the recessed portion 16c, it is possible to prevent the force or moment from the adapter 6 from acting on the outer peripheral surface 5a of the torque sensor 5. In other words, it is possible to prevent the force or moment acting on the outer peripheral surface 5a of the torque sensor 5 from being detected as torque by the torque sensor 5. Thus, it is possible to prevent the torque detection accuracy by the torque sensor 5 from being reduced.

[0106] Furthermore, the gap between the housing 8 of the speed reducer 4 and the adapter 6 is sealed by an O-ring 17 radially outward from the torque sensor 5. This prevents the fluid that enters from the outside through the gap between the base 2 and the rotating body 3 from entering the torque sensor 5 side.

[0107] The gap between the adapter 6 and the base 2 is also sealed by the O-ring 18. This prevents the liquid that has entered from the outside through the gap between the base 2 and the rotating body 3 from entering the radially inner side of the adapter 6.

[0108] As a method of preventing the liquid from entering through the gap between the base 2 and the rotating body 3, there is also a method of sealing the cylindrical gap between the speed reducer 4 and the base 2. According to this method, a single O-ring may be used.

[0109] However, in this case, during the operation of fitting the adapter 6 to the base 2, the sliding resistance of the O-ring that is compressed between the reducer 4 and the base 2 acts. Therefore, there is a case where the operator cannot recognize the start of the fitting by touch. In addition, there is a disadvantage that the fitting surface is damaged or the assembly is tilted due to tightening the bolt 13 in an improperly fitted state.

[0110] According to the present embodiment, the O-ring 17 is compressed between the planes 6c and 8c that are orthogonal to the first axis A. Thus, the sliding resistance of the O-ring 17 does not work in the operation of fitting the first fitting portion 15 of the adapter 6 into the recessed portion 14 of the base 2. Therefore, the operator can easily recognize the start of fitting by touch, and can assemble correctly.

[0111] In this embodiment, the O-ring 17 is compressed radially outward of the torque sensor 5 between the housing 8 and the adapter 6 in the direction of the axis A to collapse the O-ring 17. This prevents the torque sensor 5 from detecting the force or moment acting on the torque sensor 5 via the O-ring 17 as torque.

[0112] In this embodiment, the base 2, the adapter 6, and the torque sensor 5 are fastened together to be fixed at the same distance around the first axis A. Alternatively, the base 2 and the adapter 6, and the adapter 6 and the torque sensor 5 may be fixed at the same distance around the first axis A, respectively.

[0113] By separating the fixing of the base 2 and the adapter 6 and the fixing of the adapter 6 and the torque sensor 5, the adapter 6 and the torque sensor 5 can be fixed in advance. Thus, the torque sensor 5 and the adapter 6 can be managed as a unit.

[0114] Alternatively, the base 2 and the adapter 6 may be fixed radially outward of the torque sensor 5. In this case, the size of the bolts 13 can be increased, and the number of the bolts 13 can be reduced.

[0115] Furthermore, although the O-rings 17 and 18 are used as the sealing members, other arbitrary sealing members such as annular gaskets may be used instead.

[0116] In this embodiment, the radial positions of the O-rings 17 and 18 are roughly guided by the inner outer peripheral surface 5a or the first fitting portion 15. Alternatively, the radial positions of the O-rings 17 and 18 may be defined by forming O-ring grooves in the adapter 6, the housing 8 or the base 2.

[0117] In addition, as the adapter 6, an adapter having sufficiently higher rigidity than the base 2 and capable of suppressing deformation of the base 2 is exemplified. Alternatively, when the rigidity of the base 2 is high, as the adapter 6, an adapter having low rigidity may be adopted.

[0118] According to the present disclosure, there is an advantage that even if the rigidity of the first member 2 to which the speed reducer 4 is fixed is low, the torque acting on the first member 2 from the speed reducer 4 can be detected with high accuracy.

[0119] The embodiments of the present disclosure have been described in detail, but the present disclosure is not limited to the above-mentioned embodiments. These embodiments can be added, replaced, changed, partially deleted, etc. in various ways without departing from the scope of the main purpose of the invention, or without departing from the idea and purpose of the present disclosure derived from the contents recorded in the claims and their equivalents. For example, in the above-mentioned embodiments, the order of each action can be changed, the order of each processing can be changed, some actions corresponding to the conditions can be omitted or added, and some processing corresponding to the conditions can be omitted or added, without being limited to the above-mentioned examples. In addition, the same applies to the case where numerical values ​​or formulas are used in the description of the above-mentioned embodiments.

[0120] Description of reference numerals:

[0121] 1: Robot

[0122] 2: First component (base)

[0123] 3: Second component (rotating body)

[0124] 4: Reducer

[0125] 5: Torque sensor

[0126] 5a: Outer surface

[0127] 6: Adapter

[0128] 7: Output part (movable part)

[0129] 8: Shell (fixed part)

[0130] 16: Fitting part (recessed part)

[0131] 16a: Inner circumference

[0132] 17: O-ring (sealing component)

[0133] 18: O-ring (second sealing component)

[0134] A: First axis (axis)

Claims

1. A sealing structure of a torque sensor, which is fixed between a fixed part and a first component of a reducer, wherein the reducer comprises the fixed part and a movable part, wherein the movable part is supported to be rotatable around a predetermined axis relative to the fixed part, wherein the sealing structure of the torque sensor is characterized in that: The torque sensor detects torque about the axis, The sealing structure of the torque sensor includes an annular sealing member surrounding the outer circumference of the torque sensor. The sealing member is compressed in the axial direction by the fixing portion and the first member.

2. The sealing structure of the torque sensor according to claim 1, characterized in that: The torque sensor is formed in a disk shape. A recessed portion is provided in one of the fixing portion or the first member, the recessed portion having an inner peripheral surface arranged radially outward of an outer peripheral surface of the torque sensor with a gap therebetween, The sealing member is compressed at the opening edge of the recessed portion.

3. A sealing structure of a torque sensor, which is fixed between a fixed part and a first component of a reducer, wherein the reducer comprises the fixed part and a movable part, wherein the movable part is supported to be rotatable around a predetermined axis relative to the fixed part, wherein the sealing structure of the torque sensor is characterized in that: The torque sensor is fixed to the first member via an adapter and detects torque around the axis. The sealing structure of the torque sensor includes an annular sealing member surrounding the outer circumference of the torque sensor. The sealing member is compressed by the fixing portion and the adapter in the axial direction.

4. The sealing structure of the torque sensor according to claim 3, characterized in that: The torque sensor is formed in a disk shape. A recessed portion is provided in one of the fixing portion or the adapter, wherein the recessed portion has an inner peripheral surface arranged radially outward of an outer peripheral surface of the torque sensor with a gap therebetween. The sealing member is compressed at the opening edge of the recessed portion.

5. The sealing structure of the torque sensor according to claim 3 or 4, characterized in that: The sealing structure of the torque sensor includes an annular second sealing member. The second sealing member is compressed by the first member and the adapter along the axial direction.

6. A robot, characterized in that: have: first component; The second component; a speed reducer that supports the second member so as to be rotatable about a predetermined axis relative to the first member; a torque sensor fixed between the speed reducer and the first member and detecting a torque about the axis; and an annular sealing member surrounding the outer circumference of the torque sensor, The speed reducer includes: a fixed portion that fixes the torque sensor; and a movable portion that is supported so as to be rotatable around the axis relative to the fixed portion. The sealing member is compressed in the axial direction by the fixing portion and the first member.

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