Rotary shaft structure and robot

Abstract

Provided are: a rotary shaft structure comprising a configuration capable of facilitating wiring work of a wire body from a side opposite to the side where a member for fixing the wire body is provided, with respect to a hollow section; and a robot having the rotary shaft structure. The rotary shaft structure comprises: a base section; a rotary section attached to the base section so as to be rotatable about an axis; a hollow section that includes the axis; a wire body that extends into the hollow section; and the fixing member that holds the wire body and is fixed to the base section. The fixing member is attached to a fixing member attachment portion of the base section, the portion being visible from the rotary section side through the hollow section.

Description

Rotating shaft structure and robot

[0001] The present disclosure relates to a rotating shaft structure and a robot having the rotating shaft structure.

[0002] In a rotating shaft structure such as a joint of a robot, a hollow speed reducer may be provided, and a linear body such as a cable or a tube may be inserted into the speed reducer.

[0003] At that time, in order to facilitate the insertion operation of the linear body, a technique of providing an opening in the casing of the robot is known. Also, a technique of facilitating the assembly operation by giving a certain margin to the length of the linear body and fixing the linear body at a predetermined position of the member constituting the hollow portion is known.

[0004] Japanese Patent Application Laid-Open No. 07-124883, Japanese Patent Application Laid-Open No. 2021-079494, Japanese Patent Application Laid-Open No. 2017-185597

[0005] When passing a linear body through the hollow portion of the rotating shaft structure, in order to limit the behavior of the linear body within a certain range, the linear body may need to be fixed to a fixing member such as sheet metal provided near the entrance or exit of the hollow portion. For example, when the rotating shaft structure is a joint of a robot, the sheet metal may be fixed with bolts or the like from the bottom side of the robot. In that case, the wiring operation of the linear body cannot be easily performed unless it is also from the bottom side.

[0006] However, for example, when the robot is large and heavy, it is difficult to lay the robot on its side or invert it up and down, and it is also difficult to perform the wiring operation from the bottom side. Depending on the size, shape, or weight of the machine having the rotating shaft structure, it may be difficult to perform the wiring operation from the side where the fixing member such as sheet metal is provided.

[0007] Therefore, a rotating shaft structure provided with a configuration that can easily perform the wiring operation of the linear body from the side opposite to the side where the member for fixing the linear body is provided with respect to the hollow portion is desired.

[0008] One aspect of the present disclosure is a rotating shaft structure comprising a base, a rotating part rotatably mounted to the base about an axis, a hollow part including the axis, a wire extending within the hollow part, and a fixing member holding the wire and fixed to the base, wherein the fixing member is attached to a fixing member mounting portion of the base that can be seen from the rotating part side through the hollow part.

[0009] Another aspect of this disclosure is a robot having the above-described rotating axis structure.

[0010] This is a schematic diagram of a robot having a rotating axis structure according to an embodiment. This is an axial cross-sectional view showing one example of the rotating axis structure. This is a view of the rotating axis structure of Figure 2 from the J1 arm side. This is a diagram showing one example of the configuration of a wire clamp. This is a diagram showing an example of a wire attached to the clamp of Figure 4.

[0011] Figure 1 is a schematic diagram of an industrial robot as an example of an industrial machine including a rotary axis structure according to one embodiment of the present disclosure. The illustrated robot 10 is a horizontal articulated robot also called a SCARA robot, and has a base 12, a first arm (J1 arm) 14 rotatably mounted on the base 12 about an axis 15, and a second arm (J2 arm) 16 rotatably mounted on the D1 arm 14.

[0012] The first arm 14 is configured to rotate relative to the base 12 via a reduction gear 20 by a motor 18 located inside the base 12, and the second arm 16 is configured to rotate relative to the first arm 14 by a motor 24 located inside the second arm 16. The robot 10 also has a wire body 22 which bundles cables for supplying power to the motors 18 and 24, and an air tube (described later) for supplying air to the tip of the second arm 16.

[0013] The following describes an example of the rotation axis structure of the robot 10, including the base 12 and the joint portion including the first arm (rotating part) 14. Figure 2 is an axial cross-sectional view of the rotation axis structure including the base 12, the first arm 14 and the reduction gear 20. The reduction gear 20 is configured to reduce the rotational speed of the motor 18 using gears (not shown) and transmit torque corresponding to the reduction ratio to the first arm 14. The reduction gear 20 according to this embodiment has a hollow portion 26 including the axis 15, and a wire body 22 is inserted into the hollow portion 26. As will be described later, the wire body 22 extends within the hollow portion 26 and is held or fixed to a fixing member 28 such as sheet metal, and the fixing member 28 is fixed to a fixing member mounting portion 27 which is part of the base 12.

[0014] Figure 3 is a view of the rotation axis structure around the hollow section 26 from the first arm 14 side (upper side in Figure 2). The fixing member 28 that holds the wire body 22 (not shown in Figure 3) is fixed to part 27 of the base 12 using a bolt 50 or the like to prevent it from falling off. The first arm 14 may also be provided with a plate 30 for fixing a motor 32, etc. Furthermore, a fixing member 34 made of sheet metal or the like to fix and hold the wire body connected to the motor 32 before it enters the hollow section 26 may be provided on the plate 30. The fixing member 34 can stabilize the behavior of the wire body when the first arm 14 rotates.

[0015] The fixing member 28 is attached to a portion 27 of the base 12 (base part) that can be seen from the first arm 14 (rotating part) side through the hollow portion 26. In other words, portion 27 of the base 12 can be seen from the first arm 14 side through the hollow portion 26. As a result, the fixing work of the fixing member 28 to portion 27 can be performed by inserting a tool or the like into the hollow portion 26 from the first arm 14 side, rather than from the base 12 side (the lower side in Figure 2).

[0016] A specific example of how to insert the wire body 22 into the rotating shaft structure of the robot 10 will be described below with reference to Figures 2 to 5. First, as shown in Figure 5, the wire body 22 is fixed to the fixing member 28. Here, the wire body 22 has at least one tube (in this case, an air tube for supplying air) 46 for supplying fluid to the second arm 16, etc., and at least one cable 48 for supplying power to the motors 18, 24, etc.

[0017] Next, as shown in Figure 5, the fixing member 28 with the wire body 22 fixed is inserted into the hollow portion 26 from the first arm 14 side. At this time, as shown in Figure 4, a female thread 38 is formed on the part of the fixing member 28 that is to be fixed to the part 27 of the base 12 (in this case, the flange-shaped part 36 connected to the flat plate-shaped part 40), and the bolt 50 is screwed into the female thread 38, thereby preventing the bolt 50 from falling out of the fixing member 28 during the work.

[0018] Next, the fixing member 28 is fixed to the base 12, in this case, the flange-shaped portion 36 is fixed to the portion 27 of the base 12. At this time, it is preferable to form a counterbore hole 52 in the portion 27 with an inner diameter larger than the maximum outer diameter of the male thread of the bolt 50 to a predetermined depth, and further, to form a female thread 54 into which the male thread of the bolt 50 can be screwed over a predetermined distance from the tip of the counterbore hole 52. With this configuration, the fixing work of the fixing member 28 with the bolt 50 can be performed smoothly.

[0019] In this embodiment, the portion 27 of the base 12 to which the fixing member 28 should be attached can be seen from the first arm 14 side through the hollow portion 26. Therefore, the worker attaching the wire body 22 to the robot 10 can fix the wire body 22 to the base 12 without having to perform large-scale operations such as tilting or inverting the entire robot 10. The size of the hollow portion 26 does not need to be large enough for a worker's hand to fit inside, but it is large enough to insert a tool such as a screwdriver for fastening the bolt 50.

[0020] Typically, since the air tube 46 and the cable 48 differ in thickness, rigidity, etc., it is preferable that they be fixed to different parts of a single fixing member 28. For example, the fixing member 28 has a first flat plate portion 40 and a second flat plate portion 41 formed perpendicular to each other, and as shown in Figure 4, the first flat plate portion 40 has a hole 44 into which a fastener 62 such as a cable tie can be inserted. Similarly, the second flat plate portion 41 has a hole 42 into which a fastener 60 such as a cable tie can be inserted. With this structure of the fixing member 28, the air tube 46 and the cable 48 can be fixed to different parts of the fixing member 28, while the whole can be handled as essentially a single bundle of wires.

[0021] In the illustrated example, the two flat portions 40 and 41 are formed to be approximately perpendicular, but this is not limited to this. For example, the angle between the flat portions 40 and 41 can be 30 degrees or more, 45 degrees or more, or 60 degrees or more. Also, the angle between the flat portions 40 and 41 can be 120 degrees or less, 135 degrees or less, or 150 degrees or less. Within this angle range, the linear body 22 can be treated in roughly the same way as in the illustrated example where the two flat portions 40 and 41 form an angle of approximately 90 degrees.

[0022] The rotating shaft structure according to this embodiment has a reduction gear 20 with a hollow section 26, but the disclosure is not limited thereto. For example, it is also possible to provide a motor with a hollow section and pass a wire through the hollow section of the motor. Furthermore, in the above description, the base 12 corresponds to the base and the first arm 14 corresponds to the rotating section, but the disclosure can also be applied to a rotating shaft structure in which the first arm 14 corresponds to the base and the second arm 16 corresponds to the rotating section.

[0023] According to the above embodiment, the operator can perform the work while visually inspecting the mounting location of the fixing member through the hollow section from the rotating part side. Therefore, even when the fixing member should be fixed to the base side, the work can be performed from the rotating part side without reversing the robot or other machine. In this case, horizontal articulated robots often have a structure that makes it difficult to access from the base side, and therefore this disclosure is particularly useful. Furthermore, by engaging the bolt for attaching the fixing member to the base with a female thread formed on the fixing member, the bolt can be prevented from falling out during work. In addition, if the filament includes a tube and a cable, attaching each to a different part of the fixing member makes handling the filament easier.

[0024] The following additional information is disclosed regarding the above embodiments and modifications.

[0025] (Note 1) A rotating shaft structure comprising a base, a rotating part rotatably mounted to the base about an axis, a hollow part including the axis, a wire extending within the hollow part, and a fixing member that holds the wire and is fixed to the base, wherein the fixing member is attached to a fixing member mounting portion of the base that can be seen from the rotating part side through the hollow part.

[0026] (Note 2) The rotary shaft structure described in Note 1, having a reduction gear equipped with the hollow section.

[0027] (Note 3) The rotating shaft structure according to Note 1 or 2, wherein the fixing member has a female thread and is attached to the fixing member mounting portion by a bolt engaged with the female thread.

[0028] (Note 4) The rotating shaft structure according to any one of Notes 1 to 3, wherein the linear body has a tube for fluid supply and a cable for power supply, and the fixing member has a first flat plate portion to which the tube is fixed and a second flat plate portion to which the cable is fixed.

[0029] (Note 5) The rotational shaft structure according to Note 4, wherein the angle between the first flat plate portion and the second flat plate portion is 30 degrees or more and 150 degrees or less.

[0030] (Note 6) A robot having a rotating shaft structure as described in any one of Notes 1 to 5.

[0031] (Note 7) The robot is a horizontal articulated robot, as described in Note 6.

[0032] 10 Robot 12 Base 14 First Arm 16 Second Arm 18, 24 Motor 20 Reducer 22 Wire Body 26 Hollow Section 27 Mounting Part for Fixing Member 28 Fixing Member 36 Flange-shaped Section 40, 41 Flat Plate-shaped Section 46 Air Tube 48 Cable 50 Bolt 60, 62 Cable Tie

Claims

1. A rotating shaft structure comprising: a base; a rotating part rotatably mounted to the base about an axis; a hollow part including the axis; a linear body extending within the hollow part; and a fixing member holding the linear body and fixed to the base, wherein the fixing member is attached to a fixing member mounting portion of the base that can be seen from the rotating part side through the hollow part.

2. The rotary shaft structure according to claim 1, comprising a reduction gear having the hollow portion.

3. The rotating shaft structure according to claim 1 or 2, wherein the fixing member has a female thread and is attached to the fixing member mounting portion by a bolt engaged with the female thread.

4. The rotating shaft structure according to any one of claims 1 to 3, wherein the linear body has a tube for fluid supply and a cable for power supply, and the fixing member has a first flat plate portion to which the tube is fixed and a second flat plate portion to which the cable is fixed.

5. The rotational shaft structure according to claim 4, wherein the angle between the first flat plate portion and the second flat plate portion is 30 degrees or more and 150 degrees or less.

6. A robot having the rotating axis structure according to any one of claims 1 to 5.

7. The robot according to claim 6, wherein the robot is a horizontal articulated robot.

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