Power transmission device and power transmission unit

Abstract

This invention provides a technology that allows for easy identification of misalignment between the main body of a power transmission device and its mating component. [Solution] A power transmission device comprising a main body 30 connected to a mating member 28 located outside the power transmission device, and a device-side alignment mark 72 provided on the main body 30 and cooperating with a mating-side alignment mark 70 provided on the mating member 28 to identify the misalignment between the main body 30 and the mating member 28. By recognizing the relative positions of the mating-side alignment mark 70 and the device-side alignment mark 72, the misalignment between the main body 30 and the mating member 28 can be easily identified.

Description

Technical Field

[0001] The present disclosure relates to a power transmission device and a power transmission unit.

Background Art

[0002] Patent Document 1 discloses a power transmission device including a main body portion connected to a mating member.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When a strong impact load or the like is applied to the main body portion or the mating member of the power transmission device, displacement between the main body portion and the mating member may occur. In the case where such displacement between the main body portion and the mating member occurs, a power transmission device that takes measures to easily identify it has not yet been proposed.

[0005] Therefore, one object of the present disclosure is to provide a technique that can easily identify displacement between the main body portion and the mating member of a power transmission device.

Means for Solving the Problems

[0006] One aspect of the present disclosure is a power transmission device. This power transmission device includes a main body portion connected to a mating member disposed outside the power transmission device, and a device-side mating mark portion provided on the main body portion and cooperating with a mating-side mating mark portion provided on the mating member to identify displacement between the main body portion and the mating member.

[0007] Another aspect of the present disclosure is a power transmission unit. This power transmission unit comprises a power transmission device as described above and a mating member connected to the main body and provided with the mating mark portion. [Effects of the Invention]

[0008] According to this disclosure, it becomes possible to easily identify the misalignment between the main body of the power transmission device and the mating member. [Brief explanation of the drawing]

[0009] [Figure 1] This is a perspective view showing a power transmission device according to an embodiment. [Figure 2] This is a perspective view showing a power transmission unit of an embodiment. [Figure 3] Figure 2 is a partial cross-sectional side view showing a portion of the power transmission unit. [Figure 4] Figure 4(A) is a side cross-sectional view of the area around section A in Figure 2, and Figure 4(B) is a cross-sectional view of section BB in Figure 4(A). [Figure 5] This is a perspective view of the area around section B in Figure 2, from a different viewpoint. [Figure 6] This is a view of the area around section B in Figure 2, seen from the radially inner side. [Figure 7] This diagram shows the state in which the first mating side alignment mark and the first device side alignment mark are misaligned from their reference positions. [Figure 8] This figure shows the state in which the second mating side alignment mark and the second device side alignment mark are misaligned from their reference positions. [Modes for carrying out the invention]

[0010] Embodiments for implementing the power transmission device of this disclosure are described below. The same or equivalent elements are denoted by the same reference numerals, and redundant descriptions are omitted. For the sake of clarity, components are omitted, enlarged, or reduced in each drawing. The drawings should be viewed in accordance with the orientation of the reference numerals.

[0011] Refer to Figure 1. Hereinafter, the direction along the rotational centerline of the output body 38 (described later) of the power transmission device 10 will be referred to as the axial direction, and the radial and circumferential directions relative to that rotational centerline will be referred to as the radial direction and circumferential direction, respectively. The power transmission device 10 is incorporated into the master machine. The power transmission device 10 transmits the power generated by the prime mover and can drive the driven elements (not shown) of the master machine by outputting that power. The master machine is, for example, (1) robots such as industrial robots and service robots, (2) industrial machinery such as machine tools and construction machinery, (3) transportation equipment such as conveyors, and (4) various machines such as vehicles.

[0012] The parent machine in this embodiment is a robot, more specifically, an articulated robot. An articulated robot comprises multiple joints and multiple link members connected at the joints. The power transmission device 10 in this embodiment connects adjacent link members at the joints and outputs rotation to one of them, thereby enabling them to rotate relative to each other. The power transmission device 10 in this embodiment is incorporated into each of the multiple joints.

[0013] The power transmission device 10 in this embodiment comprises a prime mover 12 and a reduction gear 14 that reduces and outputs the rotation input from the prime mover 12. The prime mover 12 is, for example, a motor. The specific motor is not particularly limited, and various motors such as AC motors and DC motors may be used. The prime mover 12 comprises a prime mover output shaft (not shown), a prime mover body (not shown) that rotates the prime mover output shaft, and a prime mover casing 16 that houses these. The prime mover body is composed of, for example, a stator and a rotor (not shown).

[0014] The gearbox 14 comprises a gearbox input shaft (not shown) to which rotation is input from the prime mover output shaft, a reduction mechanism (not shown) that reduces the rotation input to the gearbox input shaft, a gearbox casing 18 that houses the reduction mechanism, etc., and an inner member 20 arranged inside the gearbox casing 18. The specific example of the reduction mechanism is not particularly limited and may be an eccentric oscillating type reduction mechanism, a flexible meshing type reduction mechanism, a simple planetary reduction mechanism, etc. The specific example of the eccentric oscillating type reduction mechanism is not particularly limited and may be a center crank type or a split type. The specific example of the flexible meshing type reduction mechanism is not particularly limited and may be a cup type, a top hat type, a cylindrical type, etc. In addition to a gear mechanism, the reduction mechanism may also be a traction drive, etc. The gearbox casing 18 is connected to the prime mover casing 16 by bolts, etc.

[0015] Refer to Figures 2 and 3. The power transmission device 10 constitutes part of the power transmission unit 26. The power transmission unit 26 comprises the power transmission device 10 and a mating member 28 which is the connecting partner of the power transmission device 10 and is located outside the power transmission device 10. The mating member 28 includes a first mating member 28A and a second mating member 28B. Each of the first and second mating members 28A and 28B is composed of a link member which is connected, for example, at a joint of a robot. Specific examples of the first and second mating members 28A and 28B are not particularly limited.

[0016] The power transmission device 10 includes a main body 30 connected to a mating member 28. The main body 30 includes a first main body 30A connected to a first mating member 28A and a second main body 30B connected to a second mating member 28B. The second main body 30B is rotatable relative to the first main body 30A. In this embodiment, an example is described in which the first main body 30A is the aforementioned gearbox casing 18 and the second main body 30B is the aforementioned inner member 20.

[0017] In this embodiment, the first mating member 28A serves as the support member 32 that supports the power transmission device 10, and the second mating member 28B serves as the driven member 34 driven by the power transmission device 10. The driven member 34 forms part of the driven element of the parent machine. In this embodiment, the first main body portion 30A serves as the supported body 36 connected to the support member 32, and the second main body portion 30B serves as the output body 38 connected to the driven member 34. A rotation decelerated from the rotation of the input shaft of the speed reducer is transmitted to the output body 38 via the speed reduction mechanism. The output body 38 can output rotation to the driven member 34, thereby driving the driven element including the driven member 34. A main bearing 40 that supports the output body 38 is disposed between the supported body 36 and the output body 38.

[0018] The mating member 28 includes a connected portion 44 connected to a connecting portion 42 provided on the main body portion 30. In this embodiment, the connecting portion 42 of each of the main body portions 30A and 30B is provided on the axial end face portion on one axial side (the left side in the drawing of FIG. 3) of each of the main body portions 30A and 30B. In this embodiment, the connected portion 44 of each of the mating members 28A and 28B is disposed on one axial side with respect to the connecting portion 42 of each of the main body portions 30A and 30B. In this embodiment, the connected portions 44 of the first and second mating members 28A and 28B are annular, and the connecting portions 42 of the first and second main body portions 30A and 30B are annular. The connecting portion 42 of the first main body portion 30A is disposed radially outside the connecting portion 42 of the second main body portion 30B. Also, the connected portion 44 of the first mating member 28A is disposed radially outside the connected portion 44 of the second mating member 28B. The positions of the connected portion 44 of the mating member 28 and the connecting portion 42 of the main body portion 30 are not particularly limited.

[0019] The connected part 44 of the mating member 28 and the connecting part 42 of the main body part 30 are connected by being fastened with a screw member 46. The screw member 46 is inserted into a main body hole 48 provided in the connecting part 42 of the main body part 30. At least a part of the main body hole 48 of this embodiment is provided with an internal thread part. The screw member 46 of this embodiment fastens the mating member 28 and the main body part 30 by being screwed into the internal thread part of the main body hole 48. In addition to this, the screw member 46 may fasten the mating member 28 and the main body part 30 by being screwed into a nut provided separately from the connecting part 42 of the main body part 30. In this embodiment, a plurality of main body holes 48 are provided at intervals in the circumferential direction in the connecting part 42 of the main body part 30, and the mating member 28 and the main body part 30 are connected by a plurality of screw members 46 inserted into each of the main body holes 48.

[0020] The mating member 28 includes a through hole 52 through which the shaft part 46a of the screw member 46 is inserted, and the shaft part 46a is provided with a gap 50. The gap 50 is provided in the entire circumferential range around the shaft part 46a of the screw member 46 when the mating-side mating mark part 70 of the mating member 28 and the device-side mating mark part 72 of the main body part 30, which will be described later, are in the reference positions.

[0021] The mating member 28 and the main body part 30 include a pair of inro surfaces 54 provided on the circumferential surfaces facing each other in the radial direction and fitting in an inro manner. The mating member 28 and the main body part 30 are connected in a state where the respective inro surfaces 54 are inro-fitted.

[0022] The first mating member 28A includes a cover part 56 that covers the first main body part 30A, and a window part 58 formed in the cover part 56. The cover part 56 of this embodiment includes an axial cover part 56A that covers the axial side surface of the first main body part 30A from the axial direction, and a radial cover part 56B that covers the outer peripheral surface of the first main body part 30A from the radial direction. In this embodiment, the aforementioned connected part 44 is provided in the axial cover part 56A. The radial cover part 56B of this embodiment has a cylindrical shape such as a cylindrical shape, for example, and a part thereof is provided with the aforementioned inro surface 54. The window part 58 of this embodiment is formed in the radial cover part 56B. The shape of the radial cover part 56B is not limited to a cylindrical shape, and may have various cylindrical shapes such as an elliptical cylindrical shape or a rectangular cylindrical shape.

[0023] The second main body portion 30B may have a hollow portion 60 that penetrates in the axial direction. The second mating member 28B may have a through hole 62 that forms a continuous internal space together with the hollow portion 60 of the second main body portion 30B. In addition, the second main body portion 30B may have a solid structure without a hollow portion 60.

[0024] Refer to Figures 4(A), 4(B), 5, and 6. The mating member 28 is provided with a mating side alignment mark portion 70. In this embodiment, the mating side alignment mark portion 70 includes a first mating side alignment mark portion 70A provided on the first mating member 28A and a second mating side alignment mark portion 70B provided on the second mating member 28B.

[0025] The power transmission device 10 includes a device-side alignment mark portion 72 provided on the main body portion 30. In this embodiment, the device-side alignment mark portion 72 includes a first device-side alignment mark portion 72A provided on the first main body portion 30A and a second device-side alignment mark portion 72B provided on the second main body portion 30B.

[0026] The device-side alignment mark 72 works in cooperation with the corresponding mating-side alignment mark 70 to identify the positional misalignment between the mating member 28 and the main body 30 in the pre-determined direction of misalignment. The mating-side alignment mark 70 and the device-side alignment mark 72 can also be said to be for identifying the positional misalignment between the mating member 28 and the main body 30 in the pre-determined direction of misalignment. Specifically, the first device-side alignment mark 72A corresponds to the first mating-side alignment mark 70A and works in cooperation with the first mating-side alignment mark 70A to identify the positional misalignment between the first mating member 28A and the first main body 30A in the pre-determined direction of misalignment. The second device-side alignment mark 72B corresponds to the second mating-side alignment mark 70B and works in cooperation with the second mating-side alignment mark 70B to identify the positional misalignment between the second mating member 28B and the second main body 30B in the pre-determined direction of misalignment. In this embodiment, an example in which the pre-determined direction of misalignment is the circumferential direction will be described.

[0027] The mating mark portion 70 and the device-side alignment mark portion 72, which correspond to each other, are provided at adjacent locations on the mating member 28 and the main body portion 30. In this embodiment, the first mating mark portion 70A and the first device-side alignment mark portion 72A are provided at radially adjacent locations on the first main body portion 30A and the first mating member 28A. To achieve this, as in this embodiment, the first mating mark portion 70A and the first device-side alignment mark portion 72A may be provided at the corner portion 74 formed by the first mating member 28A and the first main body portion 30A. In this embodiment, the second mating mark portion 70B and the second device-side alignment mark portion 72B are provided at axially adjacent locations on the second main body portion 30B and the second mating member 28B. In this embodiment, the second device side alignment mark portion 72B and the second mating side alignment mark portion 70B are provided at locations where they are flush with the second main body portion 30B and the second mating member 28B.

[0028] The mating mark portion 70 and the device-side mating mark portion 72, which correspond to each other, are provided on the surfaces of the mating member 28 and the main body portion 30. Here, "surface" refers to the combined concept of the outer and inner surfaces of the members being referred to. In this embodiment, the first mating mark portion 70A is provided on the inner surface of the first mating member 28A, more specifically on the inner surface of the axial cover portion 56A of the first mating member 28A. In this embodiment, the first device-side mating mark portion 72A is provided on the outer surface of the first main body portion 30A, more specifically on the outer surface of its outer periphery. In this embodiment, the second mating mark portion 70B is provided on the inner surface of the second mating member 28B, more specifically on the inner surface of its through hole 62. In this embodiment, the second device-side mating mark portion 72B is provided on the inner surface of the second main body portion 30B, more specifically on the inner surface of its hollow portion 60.

[0029] The mating mark portion 70 may be composed of a recess or protrusion provided on the mating member 28. Here, a recess or protrusion refers to a portion formed integrally with other parts of the mating member 28 on its surface. The device-side mating mark portion 72 may be composed of a recess or protrusion provided on the surface of the main body portion 30. Here, a recess or protrusion refers to a portion formed integrally with other parts of the main body portion 30 on its surface. In this embodiment, each mating mark portion 70, 72 is composed of a linear recess, that is, a groove. In addition, each mating mark portion 70, 72 may be composed of a linear protrusion, that is, a ridge. The recesses constituting each mark portion 70, 72 may be provided by cutting or otherwise cutting a part of the surface of the mating member 28 or the main body portion 30.

[0030] In this embodiment, the mating mark portion 70 and the device-side alignment mark portion 72, which correspond to each other, are continuous with the boundary portion 76 between the mating member 28 and the main body portion 30. The first device-side alignment mark portion 72A is continuous with the boundary portion 76 between the first mating member 28 and the first main body portion 30 and comprises a first portion 72Aa that is recognizable from the outside and a second portion 72Ab that is continuous with the boundary portion 76 and is covered by the first mating member 28A. The second portion 72Ab of the first device-side alignment mark portion 72A is covered by the first mating member 28A and is therefore not recognizable from the outside.

[0031] In this embodiment, the mating mark portion 70 and the device-side mating mark portion 72 are linear in shape, extending from the boundary portion 76 between the mating member 28 and the main body portion 30. Specifically, the first mating mark portion 70A is linear in shape, extending radially from the boundary portion 76 between the first mating member 28A and the first main body portion 30A, and the first device-side mating mark portion 72A is linear in shape, extending axially from its boundary portion 76. The second mating mark portion 70B is linear in shape, extending axially from the boundary portion 76 between the second mating member 28B and the second main body portion 30A, and the second device-side mating mark portion 72B is linear in shape, extending axially from its boundary portion 76. In this embodiment, all mark portions 70 and 72 are linear in shape.

[0032] The mating mark portion 70 and the device-side mating mark portion 72, which correspond to each other, form lines with equivalent line widths L70 and L72. The line width L70 of the mating mark portion 70 and the line width L72 of the device-side mating mark portion 72 are equivalent. Here, line widths L70 and L72 refer to the dimensions of the mark portions 70 and 72 in the width direction perpendicular to the length direction of the line formed by the mark portions 70 and 72. This width direction is also the direction in which the mark portions 70 and 72 are adjacent to other parts of the surface of the mating member 28 or the main body portion 30. Here, "equivalent" is a concept that includes identical or nearly identical.

[0033] Refer to Figures 7 and 8. Figure 7 shows the first mating side alignment mark 70A and the first device side alignment mark 72A as seen from arrow V in Figure 4(A) through the window 58 of the first mating member 28A. The mating side alignment mark 70 and the device side alignment mark 72, which correspond to each other, are aligned to be placed at predetermined reference positions. In Figures 7 and 8, the state in which each mark 70 and 72 are placed at the reference position is shown by a dashed line, and the state in which they are misaligned from the reference position is shown by a solid line.

[0034] In this embodiment, each mark portion 70 and 72 is linear in shape with the same line width. The reference position in this embodiment is the position where the positions of both sides 78 of each mark portion 70 and 72 in the assumed displacement direction (here, the circumferential direction) align at the boundary portion 76 between the mating member 28 and the main body portion 30. Alternatively, each of the corresponding mark portions 70 and 72 may be formed by dividing a predetermined shape (e.g., a circular shape, a polygonal shape, etc.) into two parts, and the position where the combination of each mark portion 70 and 72 exhibits the predetermined shape may be used as the reference position. Alternatively, the position where the positions of the predetermined parts indicated by each mark portion 70 and 72 (e.g., the arrowhead of an arrow mark) coincide in the assumed displacement direction may be used as the reference position. Thus, the shape of each mark portion 70 and 72, and the conditions that each mark portion 70 and 72 must satisfy when they are at the reference position, are not particularly limited, and various shapes and conditions may be adopted.

[0035] By recognizing that the relative positions of the mating side alignment mark 70 and the device side alignment mark 72 are at the reference position, it is possible to determine that there is no misalignment between the main body 30 and the mating member 28 in the assumed misalignment direction. Furthermore, by recognizing that the relative positions of the mating side alignment mark 70 and the device side alignment mark 72 are misaligned from the reference position in the assumed misalignment direction, and by recognizing the degree of that misalignment from the reference position, it is possible to determine whether there is misalignment between the main body 30 and the mating member 28 in the assumed misalignment direction, and to determine the degree of that misalignment. In other words, by recognizing the relative positions of the corresponding mating side alignment mark 70 and the device side alignment mark 72, it becomes possible to determine whether there is any misalignment between the main body 30 and the mating member 28 and the degree of that misalignment. The specific means for recognizing the relative positions of the corresponding mating side alignment mark 70 and the device side alignment mark 72 are not particularly limited. For example, these relative positions may be recognized by visual inspection by an operator, or they may be recognized by image processing of images captured by an imaging device such as a camera.

[0036] An example of how to assemble the power transmission unit 26 described above will be explained. We will consider the case where the mating member 28 is connected to the main body 30. In this case, the main body 30 and the mating member 28 are aligned in the assumed misalignment direction so that the mating mark portion 70 and the device side mating mark portion 72, which are corresponding to each other, are positioned at the reference position. After this, the relative positions of the two are fixed by connecting the mating member 28 to the main body 30.

[0037] In this embodiment, the screw member 46 is screwed into the female threaded portion of the main body hole 48 of the main body 30 with the shaft portion 46a of the screw member 46 passed through the through hole 52 of the mating member 28. At this time, the tightening of each of the multiple screw members 46 is loosened to allow slight adjustment of the relative position of the mating member 28 with respect to the main body 30. In this state, the main body 30 and the mating member 28 are aligned in the assumed misalignment direction so that the mating side alignment mark portion 70 and the device side alignment mark portion 72 are positioned at the reference position. After this, the mating member 28 is connected to the main body 30 by tightening the screw member 46, and the relative position of the two is fixed.

[0038] The effects of the power transmission device 10 and power transmission unit 26 described above will now be explained.

[0039] When a strong impact load is applied to the main body 30 or mating member 28 of the power transmission device, a misalignment between the main body 30 and the mating member 28 may occur, accompanied by a misalignment in the expected direction of the mating-side alignment mark 70 and the device-side alignment mark 72 from a predetermined reference position. Even when such a misalignment occurs, by recognizing the relative positions of the mating-side alignment mark 70 and the device-side alignment mark 72, it becomes possible to easily identify the presence and degree of misalignment between the main body 30 and the mating member 28 of the power transmission device 10. When it is necessary to control the position of the driven element of the master machine with high precision, it is desirable to identify and correct a large misalignment between the mating member 28 and the main body 30 as early as possible. According to this embodiment, there is an advantage in that such misalignment can be identified early and correction work to eliminate the misalignment can be performed early. In particular, when power transmission units 26 are incorporated in multiple locations on the master machine as in this embodiment, there is an advantage in being able to quickly identify which power transmission unit 26 is experiencing the misalignment.

[0040] If the alignment marks 70 and 72 were made of ink, paint, etc., there would be a problem in that the ink, etc. would easily wear out over time. In this embodiment, each of the alignment marks 70 and 72 is made of a recess. Therefore, compared to the case in which the alignment marks 70 and 72 are made of ink, paint, etc., they are less likely to wear out over time, so that the alignment marks 70 and 72 can be recognized for a long period of time. A similar effect can be obtained if at least one of the alignment marks 70 and 72 is made of a convex part instead of a recess. However, in order to reduce the burden required for processing to provide the alignment marks 70 and 72, it is preferable to make at least one of the mating side alignment mark 70 and the device side alignment mark 72 of a recess.

[0041] Since the power transmission device 10 outputs rotation, torque acts on each main body 30. For example, when rotational torque is transmitted by the power transmission device 10 to the second main body 30B, which becomes the output body 38, that rotational torque acts on it. Also, when rotational torque is transmitted by the power transmission device 10 to the first main body 30A, which becomes the supported body 36, a reaction torque acts on it due to the effect of the reaction. Due to this effect, when a large torque is acted on each main body 30 due to impact or the like, a circumferential misalignment of the mating member 28 and the main body 30 from the reference position may occur. In addition, a circumferential misalignment of the mating member 28 and the main body 30 may also occur due to the loosening of the screw member 46 due to the effects of vibration or the like. The device-side alignment mark portion 72 in this embodiment works in cooperation with the corresponding mating-side alignment mark portion 70 to identify the circumferential misalignment of the mating member 28 and the main body 30. Therefore, even when a misalignment occurs in the circumferential direction between the mating member 28 and the main body 30, there is the advantage that the misalignment can be identified using the respective alignment marks 70 and 72.

[0042] The device-side alignment mark section 72 in this embodiment includes a first device-side alignment mark section 72A for identifying the misalignment between the first mating member 28A and the first main body section 30A, and a second device-side alignment mark section 72B for identifying the misalignment between the second mating member 28B and the second main body section 30B. Therefore, by recognizing the relative positions of the first mating member-side alignment mark section 70A and the first device-side alignment mark section 72A, it becomes possible to identify the misalignment between the first mating member 28A and the first main body section 30A in the assumed misalignment direction. Furthermore, by recognizing the relative positions of the second mating member-side alignment mark section 70B and the second device-side alignment mark section 72B, it becomes possible to identify the misalignment between the second mating member 28B and the second main body section 30B in the assumed misalignment direction. Consequently, by using these, when the rotational position of the driven element, including the driven member 34, deviates from the correct position, it becomes possible to quickly identify whether the positional misalignment in the expected direction is occurring in the pair of the first mating member 28A and the first main body 30A, or in the pair of the second mating member 28B and the second main body 30B. The correct position here refers to the relative position of the driven element in the rotational direction with respect to the output body 38 of the power transmission device 10, which is the position where the driven element should be when each of the alignment marks 70 and 72 is in the reference position.

[0043] The alignment mark portion 72 on the device side and the alignment mark portion 70 on the mating side extend from the boundary portion 76 between the mating member 28 and the main body portion 30, forming a linear shape with equivalent line width. As a result, the position where the positions of both sides 78 of each alignment mark portion 70 and 72 are aligned at the boundary portion 76 between the mating member 28 and the main body portion 30 becomes the reference position. When a misalignment occurs from this reference position, the positions of both sides 78 of each mark portion 70 and 72 at the boundary portion 76 between the mating member 28 and the main body portion 30 will shift, making it easier to recognize the misalignment.

[0044] The mating member 28 is provided with a through hole 52 through which the shaft portion 46a of the screw member 46 is inserted with a gap 50. As a result, a positional misalignment of 50 can occur between the mating member 28 and the main body portion 30. Even if such a positional misalignment occurs between the mating member 28 and the main body portion 30 due to the gap 50, the misalignment between the two can be identified using the alignment marks 70 and 72 provided on the mating member 28 and the main body portion 30, respectively.

[0045] Next, other features of the power transmission device 10 and power transmission unit 26 described above will be explained. Refer to Figures 4 and 7. The first device side alignment mark portion 72A is provided on the outer circumference of the first main body portion 30A. The cover portion 56 (radial cover portion 56B) of the first mating member 28A covers at least a part of the outer circumference of the first main body portion 30A. The cover portion 56 covers at least a part of the first device side alignment mark portion 72A, assuming that the cover portion 56 does not have a window portion 58. In this embodiment, it covers the entire first device side alignment mark portion 72A. In this embodiment, the first device side alignment mark portion 72A is provided at the axial end 30Aa of the outer circumference of the first main body portion 30A (see also Figure 1).

[0046] The alignment mark portion 72A on the first device side and the alignment mark portion 70A on the first mating side are provided in a position where at least a part of them can be recognized from the outside through the window portion 58. Here, "position recognizable from the outside" may be a position recognizable by visual inspection by an operator from the outside, or a position recognizable in an image captured by an imaging device from the outside. Here, "outside" means the outside of the power transmission unit 26, which is a combination of the power transmission device 10 and the mating member 28. In order to satisfy this condition of "recognizable from the outside," if there are other members covering the power transmission unit 26, it is sufficient that the alignment marks 70 and 72 can be recognized when the power transmission unit 26 is inspected from the outside, assuming that there are no other members. In this embodiment, the window portion 58 connects the internal space between the cover portion 56 and the first main body portion 30A of the first mating member 28A with the external space outside the cover portion 56. In addition, the window portion 58 may be covered with a transparent cover material. In this case, the alignment mark portion 72 on the side of the device becomes visible from the outside through the transparent cover material and window portion 58.

[0047] When the first device side alignment mark portion 72A is covered by the cover portion 56 of the first mating member 28A, or when the first mating side alignment mark portion 70A is provided on the inner surface of the first mating member 28A, the alignment marks 70A and 72A become unrecognizable from outside the power transmission unit 26. Even in this case, the alignment marks 70A and 72A can still be recognized from the outside through the window portion 58 of the first mating member 28A.

[0048] Let us consider the case where the first device side alignment mark portion 72 is provided on the outer periphery of the first main body portion 30A, and the cover portion 56 of the first mating member 28A covers the outer periphery of the first main body portion 30A. In this case, if the first mating member 28A does not have a window portion 58, in order to make the first device side alignment mark portion 72A of the first main body portion 30A recognizable from the outside, it is necessary to expose the first device side alignment mark portion 72A from the cover portion 56 of the first mating member 28A. Here, the axial dimension of the cover portion 56 of the first mating member 28A can vary in various ways depending on the installation location of the power transmission unit 26, etc. In this case, regardless of the axial dimension of the cover portion 56 of the first mating member 28A, in order to expose the first device side alignment mark portion 72A, it is necessary to make the axial dimension of the first device side alignment mark portion 72A excessively long. In this respect, this embodiment has the advantage that the alignment mark portion 72A on the side of the first device can be recognized from the outside through the window portion 58 without increasing the axial dimension of the alignment mark portion 72A on the side of the first device.

[0049] Next, we will describe the transformation forms of each component described so far.

[0050] The power transmission device 10 described here includes an example comprising a prime mover 12 and a reduction gear 14. However, it is not limited to this, and the power transmission device 10 may include only a reduction gear 14. In this case, the prime mover 12 is not limited to a motor, but may be an engine or the like. The power transmission unit 26 only needs to include one mating member 28 from among the first mating member 28A and the second mating member 28B, which is provided with at least one mating side alignment mark portion 70.

[0051] Up to this point, we have described an example in which the pair of the first mating member 28A and the first main body 30A, and the pair of the second mating member 28B and the second main body 30B, are each provided with corresponding mating side alignment marks 70 and device side alignment marks 72. However, we are not limited to this, and the corresponding mating side alignment marks 70 and device side alignment marks 72 may be provided in only one of the former pair or the latter pair.

[0052] The first mating member 28A may become the driven member 34, and the second mating member 28B may become the support member 32. In this case, the first main body 30A becomes the output unit 38 that drives the driven member 34, and the second main body 30B becomes the supported member 36 that is supported by the support member 32.

[0053] Each of the alignment marks 70 and 72 does not necessarily have to be composed of a recess or a protrusion. For example, each of the alignment marks 70 and 72 may be composed of ink, paint, etc. applied to the surface of the mating member 28 or the main body 30. Alternatively, at least one of the mating side alignment marks 70 and the device side alignment marks 72 may be composed of a recess or a protrusion, and the other may be composed of ink, paint, etc. Alternatively, one of each of the alignment marks 70 and 72 may be composed of a recess or a protrusion, and ink or paint may be applied to that recess or protrusion.

[0054] The direction of misalignment (assumed misalignment direction) between the mating member 28 and the main body 30, as specified by the corresponding device-side alignment marks 72 and mating-side alignment marks 70, is not limited to the circumferential direction. For example, this assumed misalignment direction may be axial or radial.

[0055] The mating member 28 and the main body 30 may be connected using a method other than the screw member 46. For example, they may be connected by friction fastening.

[0056] When the mating mark portion 70 and the device-side mating mark portion 72 are linear, the line widths of the mark portions 70 and 72 may be different. In this case, for example, at the boundary portion 76 between the mating member 28 and the main body portion 30, a reference position may be set at which the position of the mark portion with a smaller line width aligns with a portion of the mark portion with a larger line width in the assumed direction of overall misalignment.

[0057] In this embodiment, an example was described in which the window portion 58 of the first mating member 28A is provided in the radial cover portion 56B. However, it is not limited to this, and the window portion 58 of the first mating member 28A may be provided in, for example, the axial cover portion 56A.

[0058] Any combination of the above components is also valid. For example, any explanatory items described in the embodiments may be combined, or any explanatory items described in the embodiments and modified forms may be combined. For example, features relating to the first mating side alignment mark portion 70A and the first device side alignment mark portion 72A (for example, features relating to the corner portion 74) may be applied to the second mating side alignment mark portion 70B and the second device side alignment mark portion 72B. Also, features relating to the first mating member 28A (for example, features relating to the cover portion 56 and the window portion 58) may be applied to the second mating member 28B.

[0059] The contents of each component described in the embodiments above are illustrative. The abstract technical ideas derived from these should not be interpreted restrictively to the contents of this specification. Many design changes, such as modifications, additions, and deletions, are possible for the contents of each component described in the embodiments. Such design changes are emphasized by the notation "this form" or "embodiment." However, design changes are also permitted for contents without such notation. The structures and numerical values ​​mentioned in the embodiments and variations naturally include those that can be considered identical when considering manufacturing tolerances, etc. Components composed of a single member in the description in this specification may be composed of multiple members. Similarly, components composed of multiple members may be composed of a single member. [Explanation of Symbols]

[0060] 10...Power transmission device, 26...Power transmission unit, 28...Mating member, 28A...First mating member, 28B...Second mating member, 30...Main body, 30A...First main body, 30B...Second main body, 46...Screw member, 46a...Shaft, 50...Gap, 52...Through hole, 56...Cover part, 58...Window part, 70...Mating side alignment mark part, 70A...First mating side alignment mark part, 70B...Second mating side alignment mark part, 72A...First device side alignment mark part, 72B...Second device side alignment mark part.

Claims

1. A power transmission device, A main body that is connected to a mating member located outside the power transmission device, A power transmission device comprising: a device-side alignment mark portion provided on the main body portion and cooperating with a mating-side alignment mark portion provided on the mating member portion to identify the misalignment between the main body portion and the mating member portion.

2. The power transmission device according to claim 1, wherein the device side alignment mark portion is formed by a recess or protrusion provided on the main body portion.

3. The power transmission device according to claim 1, wherein the device-side alignment mark portion cooperates with the mating-side alignment mark portion to identify the circumferential positional misalignment between the main body portion and the mating member.

4. The main body includes a first main body connected to a first mating member and a second main body connected to a second mating member and rotatable relative to the first main body. The power transmission device according to claim 1, wherein the device side alignment mark portion includes a first device side alignment mark portion that works in cooperation with a first mating side alignment mark portion provided on the first mating member to identify the misalignment between the first mating member and the first main body portion, and a second device side alignment mark portion that works in cooperation with a second mating side alignment mark portion provided on the second mating member to identify the misalignment between the second mating member and the second main body portion.

5. A power transmission device according to any one of claims 1 to 4, A power transmission unit comprising: a mating member connected to the main body and having a mating mark portion on the mating side.

6. The mating member is fastened to the main body by a screw member. The power transmission unit according to claim 5, wherein the mating member has a through hole through which the shaft portion of the screw member is inserted with a gap.

7. The power transmission unit according to claim 5, wherein each of the mating side alignment mark portion and the device side alignment mark portion extends from the boundary portion between the main body portion and the mating member and has a linear shape having the same line width.

8. The mating member comprises a cover portion that covers the main body portion and a window portion formed in the cover portion, The power transmission unit according to claim 5, wherein the device-side alignment mark portion and the mating side alignment mark portion are provided in a position that can be recognized from the outside through the window portion.

9. The device side alignment mark portion is provided on the outer circumference of the main body portion, The power transmission unit according to claim 8, wherein the cover portion covers the outer periphery of the main body portion.

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