JP4165019B2 - Robot joint device and assembly method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a joint device for a robot in which a second arm is rotatably connected to a first arm and an assembling method thereof.
[0002]
[Prior art]
FIG. 8 shows an example of the structure of a joint device for connecting the arms of a conventional articulated robot. In FIG. 8, a servo motor 3 is built in a frame 2 that forms the housing of the first arm 1, and the connecting body 5 rotates via the speed reducer 4 according to the rotation of the servo motor 3. It is like that. The connecting body 5 is formed by integrating a shaft portion 5 a and an annular flange portion 5 b, the shaft portion 5 a is fixed to the output portion of the speed reducer 4, and the annular flange portion 5 b is opened at the front end opening of the frame 2 by the cross roller bearing 6. Is rotatably supported. In this case, a bearing retainer flange 7 is fixed to the front end opening of the frame 2 of the first arm 1 with a plurality of bolts 8, whereby the bearing 6 is mounted in a positioned state on the front end opening of the frame 2. Yes.
[0003]
A frame 10 that forms a casing of the second arm 9 is fixed to the annular flange portion 5 b of the connecting body 5 with bolts 11. Accordingly, the connecting body and thus the second arm 9 is rotated in accordance with the rotation of the servo motor 3. A cylindrical cable support 12 is attached to the center of the annular flange portion 5 b of the connecting body 5, and the second arm 9 with respect to the first arm 1 with the cable passing through the cable support 12. In order to be able to rotate, the connecting body 5 is formed in a curved shape in which the shaft portion 5a cantilever-supports the annular flange portion 5b.
[0004]
By the way, in order to assemble the robot joint apparatus having the above-described configuration, the connecting body 5 is inserted into the frame 2 from the front end opening of the frame 2 of the first arm 1, and the shaft portion 5 a is integrally formed with the frame 2. It is inserted into and supported by a bearing 14 mounted in the cylindrical support portion 13.
[0005]
Subsequently, the bearing retainer flange 7 is fixed to the front end opening of the frame 2 with bolts 8 in a state where the cross roller bearing 6 is sandwiched between the annular flange 5 b of the connecting body 5 and the front end opening of the frame 2. Thereby, since the bearing 6 can be attached to the front end opening of the frame 2 in a positioned state, the coupling body 5 can be rotatably supported on the frame 2.
[0006]
Subsequently, the frame 10 of the second arm 9 is fixed to the annular flange portion 5b of the connecting body 5 with bolts 11 from the annular flange 5b side. Here, a window portion 15 is formed on the side surface of the frame 2 of the first arm 1 as shown in FIG. 9, and the assembling operator makes a ring in a state where a hand enters the frame 2 from the window portion 15. After inserting the bolt 11 into the bolt hole formed in the flange portion 5b, the frame 10 of the second arm 9 is fixed to the connecting body 5 by turning the bolt 11 with a hexagon wrench.
[0007]
When the connection between the connecting body 5 and the second arm 9 is completed as described above, the output portion of the speed reducer 4 and the shaft portion 5a of the connecting body 5 are fixed with the bolts 16, and then the servo motor 3 The servo motor 3 is fixed to the cylindrical support portion 13 with the input portion of the speed reducer 4 fixed to the shaft meshing with the output portion.
[0008]
Then, after a cable or the like is wired, the joint device that connects the first arm 1 and the second arm 9 can be assembled by attaching the cover 17 to the frame 2 of the first arm 1.
[0009]
[Problems to be solved by the invention]
However, with such a configuration, the frame 10 of the second arm 9 is formed on the frame 2 of the first arm 1 to fix the frame 10 of the second arm 9 to the annular flange portion 5b of the connecting body 5 of the first arm 1 with the bolts 11. The bolt 11 must be turned with a hexagon wrench by entering the hand from the narrow window 15 and is very troublesome, and the angle at which the bolt 11 can be turned in one operation is small and the work efficiency is poor. . Furthermore, it is necessary to form a window 15 on the frame 2 of the first arm 1 and to produce a cover that closes the window 15, which is expensive and poor in appearance.
[0010]
The present invention has been made in view of the above circumstances, and the object thereof is to increase the work efficiency of connecting the first arm and the second arm, reduce the cost, and improve the appearance of the arm. It is an object of the present invention to provide a robot joint device and an assembly method thereof.
[0011]
[Means for Solving the Problems]
According to the present invention, the bolt hole formed for fixing the bearing pressing member to the first arm with the bolt is formed on the first arm with the second arm rotated by a predetermined angle with respect to the first arm. Since the formed bolt holes emerge from the opposed state to the second arm so as to be visible , the rotating body is supported on the first arm by a bearing in a state where the rotating body is connected in advance to the second arm. be able to. Accordingly, the operation of connecting the rotating body to the second arm with the bolt in the first arm can be eliminated, the working efficiency can be improved, and the window portion for performing the bolting operation in the first arm is formed. This eliminates the need to reduce the cost and improves the appearance.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment in which the present invention is applied to an articulated robot will be described with reference to FIGS. FIG. 2 shows the external configuration of the robot. In FIG. 2, the robot body 21 is configured as a 6-axis small vertical articulated robot for assembly. That is, the shoulder 23 is connected to the base 22 so as to be rotatable in the horizontal direction about the vertical axis J1. A base end portion of the lower arm 24 is connected to the shoulder 23 so as to be rotatable in the vertical direction about the axis J2. An upper arm (corresponding to a first arm) 25 is connected to the tip of the lower arm 24 so as to be rotatable in the vertical direction about the axis J3. A base end portion of a wrist (corresponding to a second arm) 26 is coupled to the distal end portion of the upper arm 25 so as to be rotatable about an axis J4. A hand attachment 27 is connected to the tip of the wrist 26 so as to be rotatable about J5. A disk-shaped flange 28 is connected to the hand mounting body 27 so as to be rotatable about J6. Bolt holes 28a are formed in the flange 28 as shown in FIG. 4, and a hand and various tools (not shown) can be detachably attached.
[0014]
The shoulder 23, the lower arm 24, the upper arm 25, the wrist 26, the hand mounting body 27, and the flange 28 are connected to each other by joint devices, and a servo motor and a speed reducer are provided for each joint device. When the joint devices are driven according to the drive of the servo motor, the shoulder 23, the lower arm 24, the upper arm 25, the wrist 26, the hand attachment body 27, and the flange 28 are rotated around the axes J1 to J6. It is like that. In this case, a robot controller (not shown) is connected to the robot body 21, and various operations are executed by being controlled by the robot controller.
[0015]
FIG. 3 is a broken sectional view showing a structure of a joint device for connecting the upper arm 25 and the wrist 26. In FIG. 3, the upper arm 25 has a frame 29 as a casing, and the rotation of a servo motor (corresponding to a drive source) 31 fixed to a cylindrical support 30 integrally formed in the frame 29 is reduced by a speed reducer 32. The wrist 26 is rotated around the axis J4 shown in FIG. 2 by outputting in a decelerated state. As the speed reducer 32, a harmonic drive (trade name) is used.
[0016]
FIG. 5 is an exploded perspective view showing the speed reducer 32. In FIG. 5, the speed reducer 32 includes a wave generator 33, a flex spline 34, and a circular spline 35. The wave generator 33 is formed by mounting a ball bearing 37 configured to be elastically deformable on the outer periphery of an elliptical cam 36 attached to an input shaft. The inner ring of the ball bearing 37 is fixed to the elliptical cam 36, and the outer ring is elastically deformed according to the rotation of the elliptical cam 36. The flexspline 34 is made of a bottomed cylindrical metal having thin cup-like elasticity, and a predetermined number of teeth are formed on the outer periphery of the opening. The diaphragm at the bottom of the flexspline 34 is fixed to the output shaft. The circular spline 35 has teeth formed on the inner periphery, and the number of teeth is two more than the number of teeth formed on the flexspline 34.
[0017]
In the speed reducer 32 configured as described above, the flex spline 34 and the circular spline 35 are engaged with each other only at two 180-degree symmetrical positions. When the wave generator 33 rotates, the flex spline 34 and the circular spline 35 are engaged. The meshing position rotates and moves. In this case, since the number of teeth of the flex spline 34 is two less than the number of teeth of the circular spline 35, the flex spline 34 is equivalent to two sheets having a difference in the number of teeth in the direction opposite to the rotation direction of the wave generator 33. The rotation is the output. According to the reduction gear 32 having such a configuration, a large reduction ratio can be obtained with a simple configuration.
[0018]
Returning to FIG. 3, a connecting body 38 is connected to the speed reducer 32, and the connecting body 38 rotates according to the rotation of the servo motor 31. The connecting body (corresponding to a rotating body) 38 is formed by integrally forming an annular flange portion 38b at the tip of a curved shaft portion 38a. A shaft portion 38 a of the coupling body 38 is supported by a bearing 39 mounted in the cylindrical support portion 30, and a flex spline 34 of the speed reducer 32 is fixed to the shaft portion 38 a by a bolt 40.
[0019]
In addition, a circular spline 35 of a speed reducer 32 is fixed to the cylindrical support portion 30 with bolts 41. An elliptical cam 36 of the wave generator 33 of the speed reducer 32 is fixed to the shaft 31a of the servo motor 31 fixed to the cylindrical support 30 with bolts 42, and the wave generator 33 is placed in the flex spline 34. positioned. In this state, the two portions of the flex spline 34 that are opposed to each other by 180 ° are pushed from the inside by the wave generator 33, and the external teeth formed at the position corresponding to the pushed portion are inside the circular spline 35. Engage with teeth.
[0020]
On the other hand, the annular flange portion 38 b of the coupling body 38 is attached to the tip opening portion of the frame 29. A cable support 44 is attached to the center of the annular flange portion 38b. In order to enable the wrist 26 to rotate with respect to the upper arm 25 with the cable passing through the cable support 44, a connecting body 38 is provided. The shaft portion 38a is formed in a curved shape in which the annular flange portion 38b is cantilevered.
[0021]
In this case, a bearing pressing flange (corresponding to a bearing pressing member) 45 is fixed to the front end opening of the frame 29 of the upper arm 25 with a plurality of bolts 46, whereby the cross roller bearing 43 is fixed to the frame 29. It is mounted in a positioning state at the tip opening.
[0022]
The wrist 26 is fixed to the connecting body 38. That is, the annular flange portion 38b of the connecting body 38 and the base end portion of the frame 47 forming the casing of the wrist 26 are connected by screwing a plurality of bolts 48 from the annular flange portion 38b side.
[0023]
An oil seal 49 is mounted between the bearing retainer flange 45 and the frame 47 of the wrist 26 to prevent dust from entering the joint device.
With the configuration as described above, when the servo motor 31 rotates, the rotation of the servo motor 31 is transmitted to the list 26 via the coupling body 38 while being decelerated by the speed reducer 32, so the list 26 rotates. .
[0024]
Here, FIG. 4 is a front view of the list 26. In FIG. 4, the frame 29 of the upper arm 25 and the frame 47 of the wrist 26 are formed to have a rectangular cross section. As shown in FIG. The bolts 46 for fixing 45 to the frame 29 of the upper arm 25 and the bolt holes 29a of the frame 29 are concealed by the wrist 26.
[0025]
Next, a method for assembling the joint device for connecting the upper arm 25 and the wrist 26 in the robot main body 21 will be described.
First, the base 22, the shoulder 23, and the lower arm 24 of the robot main body 21 are assembled in this order, and then the frame 29 of the upper arm 25 is assembled to the tip of the lower arm 24.
[0026]
Next, the annular flange portion 38b and the frame 47 of the wrist 26 are joined to the annular flange portion in a state where the cross roller bearing 43 is interposed between the frame 47 of the wrist 26 and the annular flange portion 38b of the coupling body 38 that have been assembled. It fixes with the volt | bolt 48 from the 38b side (refer FIG. 6). At this time, a bearing holding flange 45 and an oil seal 49 are interposed between the cross roller bearing 43 and the frame 47 of the wrist 26. Further, a cable (not shown) or the like led out from the list 26 passes through the cable support 44.
[0027]
Subsequently, the shaft portion 38a of the coupling body 38 is inserted into the bearing 39 mounted in the cylindrical support portion 30 integrally formed in the frame 29 of the upper arm 25, and the bolt hole 45a of the bearing pressing flange 45 and The bearing retainer flange 45 is fitted into the tip opening of the frame 29 with the bolt holes 29 a (see FIG. 4) formed in the frame 29 of the upper arm 25 aligned.
[0028]
At this time, as shown in FIG. 4, when the bolt hole 45 a of the bearing holding flange 45 is obstructed by the wrist 26 and concealed from the outside, the wrist 26 is 45 ° in any direction with respect to the upper arm 25. Rotate. Then, as shown in FIG. 1, a pair of opposing bolt holes 45a out of the concealed state by the wrist 26 appears out of the concealed state by the wrist 26, so that the bolts 46 appear in the bolt holes 45a. Is inserted and screwed into the upper frame 29.
[0029]
Subsequently, the wrist 26 is further rotated by 45 ° in the same direction as the rotation direction with respect to the upper arm 25 or 90 ° in the opposite direction to the rotation direction. Then, as shown in FIG. 7, the remaining pair of bolt holes 45a out of the concealed state by the wrist 26 appears out of the concealed state by the wrist 26 among the bolt holes 45a of the bearing holding flange 45, so that the bolts 46 are inserted into the bolt holes 45a. Is inserted and screwed into the upper frame 29.
[0030]
By fixing the bearing pressing flange 45 to the frame 29 of the upper arm 25 by the above operation, the cross roller bearing 43 can be mounted on the frame 29 in a positioned state. It can be movably connected.
[0031]
Then, the circular spline 35 of the speed reducer 32 is fixed to the cylindrical support portion 30 of the frame 29 of the upper arm 25 with the bolt 41, and the flex spline 34 is inserted into the circular spline 35, and then the diaphragm of the flex spline 34 is attached. The shaft 38 a of the coupling body 38 is fixed with bolts 40.
[0032]
Subsequently, after the wave generator 33 fixed to the shaft 31 a of the servo motor 31 is inserted into the flexspline 34, the servo motor 31 is fixed to the cylindrical support portion 30 with the bolts 42. As a result, the outer teeth of the flexspline 34 and the inner teeth of the circular spline 35 are engaged with each other at two positions facing each other by 180 °.
[0033]
Subsequently, after the cables are wired, the cover 50 is attached to the frame 29 of the upper arm 25, whereby the joint device that connects the upper arm 25 and the wrist 26 can be assembled.
[0034]
According to such an embodiment, the sectional shapes of the upper arm 25 and the wrist 26 are substantially the same rectangular shape, and the bearing pressing flange 45 of the bearing retainer 45 is rotated with the wrist 26 rotated by a predetermined angle with respect to the upper arm 25. Since the bolt hole 45a and the bolt hole 29a formed in the frame 29 of the upper arm 25 escape from the state facing the wrist 26 and appear so as to be visible, the bearing retainer flange 45 is inserted into the bolt 46 in the appearance state. Thus, it can be fixed to the frame 29 of the upper arm 25. Therefore, the bearing flange is fixed to the frame of the upper arm with a bolt so that the annular flange of the coupling body is rotatably supported by the bearing, and the annular flange and the wrist are placed in the frame in the frame of the upper arm. Unlike the conventional example in which a hand is inserted and fixed with bolts from the annular flange side, it is possible to fix in advance the connecting body 38 for transmitting the rotation of the servo motor 31 to the wrist 26. Therefore, the work of bolting in the frame 29 of the upper arm 25 is not required, and the workability can be greatly improved, and it is not necessary to form a working window in the frame 29 of the upper arm 25. The cost can be reduced and the appearance of the upper arm 25 can be improved.
[0035]
In addition, since such a configuration can be implemented without significantly changing the structure of the upper arm 25, it can be easily implemented without making a significant design change.
[0036]
The present invention is not limited to the above embodiment, and can be modified or expanded as follows.
The present invention is not limited to a joint device that connects the upper arm 25 and the wrist 26, and can be applied to a joint device that connects each arm.
The speed reducer 32 is not limited to a harmonic drive, and may be a combination of spur gears or a configuration using planetary gears.
The present invention is not limited to an articulated robot, and may be applied to a scalar type robot.
[Brief description of the drawings]
FIG. 1 is a front view of an upper arm showing a list rotated by a predetermined angle in an embodiment of the present invention. FIG. 2 is a side view of a robot body. FIG. 3 is a cutaway side view of the upper arm. FIG. 5 is an exploded perspective view of the speed reducer. FIG. 6 is a broken side view of the list shown in a connected state of the connecting body. Fig. 8 Equivalent view Fig. 8 Equivalent to Fig. 3 Fig. 9 Side view of upper arm showing window
21 is a robot body, 22 is a base, 23 is a shoulder, 25 is an upper arm (first arm), 26 is a wrist (second arm), 29 is a frame, 29a is a bolt hole, 31 is a servo motor (drive source), Reference numeral 38 denotes a connecting body (rotating body), 43 denotes a cross roller bearing, 45 denotes a bearing pressing flange (bearing pressing member), 45a denotes a bolt hole, and 46 denotes a bolt.

Claims (2)

A second arm is rotatably connected to a first arm having a polygonal shape having substantially the same cross-sectional outer shape ,
A rotating body rotatably supported by a bearing on the first arm and rotated by a drive source;
A bearing pressing member that positions the bearing on the first arm by being fixed to the first arm with a bolt;
In a joint device for a robot in which the rotating body and the second arm are connected,
Before Symbol bolt hole formed in for fixing the member for the bearing retainer with bolts to the first arm, and the second arm in a state where the second arm is rotated by a predetermined angle relative to the first arm A robot joint device that emerges from a facing state so as to be visible. The second arm is rotatably connected to the first arm,
A rotating body rotatably supported by a bearing on the first arm and rotated by a drive source;
A bearing pressing member that positions the bearing on the first arm by being fixed to the first arm with a bolt;
In a joint device for a robot in which the rotating body and the second arm are connected,
Connecting the rotating body to the second arm;
The second arm is moved to the first arm until a bolt hole formed to fix the bearing pressing member to the first arm with a bolt emerges from the facing state with respect to the second arm. Rotate with respect to
A method for assembling a robot joint device, wherein the bearing pressing member is screwed onto the first arm with a bolt to mount the bearing on the first arm in a positioning state.

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