JP2002239968A - Articulation part structure of robot - Google Patents

Abstract

PROBLEM TO BE SOLVED: To expand a rotation range of a robot arm, while preventing enlargement in the diametrical direction of an articulation part in a device having a hole part to be a wiring passage in the outer circumference of a shaft part. SOLUTION: A rotor 28 rotated by a servomotor and a speed reducer and having a second arm 14 (housing 31) attached thereto is provided in a front edge face of a third arm 15, and a circumferentially long hole part 33 for letting a wire 34 to pass through is formed in an end plate 23 provided in its outer circumference. A movable side first stopper 35 and a second stopper 36 are provided in both sides of the hole part 33 in such a state that the trajectories a and b are diametrically deviated. The housing 31 of the second arm 14 is provided with a fixing side first stopper 37, on which the movable side first stopper 35 abuts when clockwise rotating the third arm 15, and a fixing side second stopper 38, on which the movable side second stopper 36 abuts when counterclockwise rotating the third arm in positions deviated circumferentially. A frame 31 is provided with a constricted part 31a escaping from lapped with the hole 33. This constitution can enlarge the rotation range B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a joint structure of a robot in which a second arm is relatively rotatably connected to a first arm by a shaft.

[0002]

For example, in an articulated robot in which a plurality of arms are rotatably connected in order,
In order to protect the wiring passing through the inside of the arm (or to ensure the safety), software regulation is performed so that the rotation range of the second arm with respect to the first arm is within a predetermined range. In order to enhance the reliability, a mechanical stopper mechanism is provided at the joint portion, and the rotation range is mechanically regulated.

FIG. 4 shows an example of the structure of a conventional joint, in which a housing 2 constituting a joint of a first arm 1 is shown.
Is formed in a substantially disc shape, and a shaft portion 5 to which a distal end portion of the housing 4 of the second arm 3 is connected is provided at a central portion thereof. The shaft 5 is rotated by a motor and a speed reducer (not shown) incorporated in the first arm 1. In this case, the first arm 1 rotates clockwise with respect to the second arm 3 in the figure. And rotated counterclockwise.

Further, an outer peripheral portion of the shaft portion 5 of the housing 2 (a position of the second arm 3 deviated from the housing 4).
Is provided with, for example, a circular hole 6 for passing a wiring (wire harness). In this case, the hole 6 is
The wiring is formed large enough to allow a connector provided at the end of the wiring to pass therethrough, and to allow the wiring to shift and move with the rotation of the first arm 1. Further, a cover 10 is provided on the second arm 3, and the end face 3 of the housing 2 is covered with the cover 10. In the second arm 3, wiring is passed through the cover 10.

[0005] A first stopper 7 is provided on the right side of the hole 6 of the housing 2 in the rotation direction, and a second stopper 8 is provided on the left side of the hole 6 in the rotation direction. On the other hand, the housing 4 of the second arm 3 is provided with a block-shaped stopper 9 located on the rotation track of the first and second stoppers 7 and 8. Thus, as shown by the imaginary line in the figure, when the first arm 1 rotates in one direction (clockwise in the figure), the first stopper 7 comes into contact with the right end face in the figure of the stopper 9. When the rotation range is restricted, and when rotating in the opposite direction (counterclockwise in the figure), the second stopper 8 comes into contact with the left end face in the view of the stopper 9 to restrict the rotation range.

However, in the above-described conventional configuration, the stoppers 7 and 8 are moved to the holes 6 due to the presence of the holes 6 serving as the wiring passages.
4, the rotation range of the first arm 1 is limited to the range indicated by A in FIG. 4 and cannot be further expanded. In this case, the hole 6 and the stoppers 7, 8 may be provided at different positions in the diametric direction, such as by providing stoppers 7, 8 on the outer peripheral side of the hole 6. This leads to an increase in size, which is in conflict with recent demands for downsizing robots.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to form a hole serving as a wiring passage located on the outer periphery of a shaft, and to increase the diameter of a joint in the diameter direction. Another object of the present invention is to provide a joint structure of a robot capable of expanding the rotation range of the arm while preventing the occurrence of the arm.

[0008]

In order to achieve the above object, a joint structure of a robot according to the present invention is characterized in that when a second arm relatively rotates in one direction with respect to a first arm, a second arm is provided.
The first stopper on the arm side of the second arm contacts the first stopper on the first arm side to restrict the rotation range, and when the second arm relatively rotates in the opposite direction, the second stopper on the second arm side Are configured to abut the second stopper on the second arm side to regulate the rotation range. At this time, the positions of the two sets of stoppers are shifted in a diametrical direction so as to be stepped, and The relative trajectory of the stopper and the relative trajectory of the second stopper are shifted in the diametrical direction (the invention of claim 1).

According to this, a hole serving as a wiring passage is formed at the outer periphery of the shaft of the housing of the first arm,
Even if there is a situation where the first stopper and the second stopper on the first arm side are provided on both sides in the circumferential direction of the hole,
By setting the positions of the first stopper and the second stopper on the second arm side as required, the rotation ranges in one direction and the opposite direction can be freely set. In this case, since the trajectory of the first stopper and the trajectory of the second stopper are displaced in the diametrical direction, for example, when the second arm rotates in one direction, the first stopper on the second arm side moves to the first arm side. It is also possible to arrange the two stoppers so as to abut on the first arm-side first stopper at a position past the circumferential direction. As a result, the arm can be prevented from being enlarged in the diameter direction, and Can be extended.

At this time, the hole forming the wiring passage can be provided in a long slot shape along the circumferential direction (the invention of claim 2). According to this, the length of the hole in the diameter direction is reduced while the function required for the hole such as the connector provided at the leading end of the wiring is passed and further, the wiring is allowed to shift. Thus, the size of the entire joint can be further reduced.

[0011] In the housing of the second arm,
The portion overlapping with the hole can be formed in a constricted shape by the relative rotation of the second arm (the invention of claim 3). According to this, it is possible to prevent the hole and the second arm from wrapping as much as possible, and it is possible to further widen the relative rotation range of the second arm with respect to the first arm.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described with reference to a vertical articulated type (6).
One embodiment applied to an (axis) robot will be described with reference to FIGS. FIG. 3 shows the external configuration of the robot main body 11 in the present embodiment in a state where the robot main body 11 is at the origin position. First, the overall configuration of the robot main body 11 will be briefly described.

That is, the base 1 installed on the installation surface of the equipment
2, the first arm 13 has an axis J1 extending in the vertical direction.
Are connected so as to be rotated (turned) around the center. A second arm 14 is connected to the distal end of the first arm 13 so as to be rotated (turned) about a horizontally extending axis J2. At the tip of the second arm 14,
The third arm 15 is connected so as to be rotated (turned) around a horizontally extending axis J3.

A fourth arm 16 is connected to the distal end of the third arm 15 so as to be coaxially rotated about an axis J4. A fifth arm 17 is connected to the tip of the fourth arm 16 so as to be rotated (turned) about the axis J5. A sixth arm 18 is connected to the end of the fifth arm 17 so as to be coaxially rotated about an axis J6. Although not shown, a tool such as a hand is attached to the flange surface at the tip of the sixth arm 18.

Each of the axis arms 13 to 18 is driven by a servomotor (only a part is shown later), and these servomotors are controlled by a robot controller (not shown) including a microcomputer or the like. It is supposed to be. Further, a teaching pendant or the like is connected to the robot controller.

Next, FIG. 1 and FIG.
Of the axis J3 connecting the second arm 14 and the third arm 15 at the origin position
2 shows a configuration of a portion, and the joint has a joint structure according to the present embodiment. In this case, the third arm 15
However, the second arm 14 functions as the first arm according to the present invention, and the second arm 14 functions as the second arm according to the present invention. Hereinafter, this joint structure will be described.

FIG. 1 shows the second arm 15 of the third arm 15.
The configuration of the end face of the portion to which the arm 14 is connected is shown from the front, and FIG. 2 schematically shows a cross-sectional structure of the third arm 15 along the line II in FIG. Here, this third
The arm 15 is provided with a housing 19 having a shape such that an upper rectangular tube-shaped portion and a lower cylindrical portion are horizontally displaced by 90 degrees in the axial direction, and the internal portions thereof are connected to each other.

Then, as shown in FIG.
5 incorporates a 4-axis servomotor 20 for rotating and driving the fourth arm 14 and a speed reducer (not shown) in the upper part of the housing 19 and the second 3-axis servo motor 21 for rotating itself (third arm 15) with respect to arm 14
And a speed reducer unit 22.
As shown in FIG. 2, the opening at the rear end face of the lower part of the housing 19 is closed by a cover 15a. As shown in FIG. 1, the rear end face of the upper part of the housing 19 (right end face in FIG. 1). The opening in () is closed by the cover 15b.

Here, as shown in FIG. 2, a circular opening 19a is provided in a lower front wall of the housing 19, and the reduction gear unit 22 is provided in the opening 19a.
Is attached, and on the front wall of the housing 19,
As shown in FIG. 1, a ring-shaped end plate 23 is attached so as to surround the opening 19a (reduction gear unit 22). The reduction gear unit 22 is composed of, for example, a well-known harmonic drive, and has a wave generator 24 having a ball bearing on the outer periphery of an elliptical cam, a cup-shaped flex spline (elastic gear) 25 arranged on the outer periphery, It is provided with a circular spline (internal gear) 26 that meshes.

At this time, the wave generator 24
Is connected to a rotary shaft 21a of a three-axis servo motor 21 mounted in the housing 19, and the circular spline (internal gear) 26 is
9, and a rotating body 28 serving as a shaft is connected to a distal end of the flexspline 25 via a mounting member 27. In this case, the rotating body 28 also serves as an inner ring of a bearing (cross roller bearing) 29, and two outer rings of the bearing 29 are fixed to the housing 19 in a so-called co-tightened state. An oil seal 30 is provided between the inner and outer rings at the tip of the bearing 29.

Then, as shown in FIG.
8 is provided with a housing 3 of the second arm 14.
1 (the outer shape is indicated by an imaginary line) is fixed by bolting. As a result, when the three-axis servo motor 21 is driven to rotate, the rotation is reduced by the speed reducer unit 22 and transmitted to the rotating body 28, whereby the third arm 15 is moved relative to the second arm 14. It is to be rotated about the axis J3. The housing 31 of the second arm 14 is covered by a cover 32 (the outer shape is indicated by an imaginary line).
The distal end portion of the cover 32 is formed in a circular shape having a size to cover the end plate 23.

As shown in FIG. 1, the end plate 23 has a hole formed in the outer periphery of the rotating body 28 (bearing 29) at a position slightly upper left in FIG. Part 33
Are formed. In the present embodiment, the hole 33 is provided in the shape of a long hole extending in the circumferential direction, and a wiring (wire harness) 34 (shown by imaginary lines) is provided in the hole 33.
From the inside of the second arm 14 (cover 32).
5 (housing 19).
In this case, a connector (not shown) provided at the end of the wiring 34 passes through the hole 33 and the third arm 1
The wiring 34 is formed in such a size (width) and length that the wiring 34 can be relatively shifted in the circumferential direction with the rotation of 5. The front end face of the housing 19 is also provided with the hole 3.
Of course, an opening part wrapped around 3 is formed.

Then, as shown in FIG.
A movable first stopper 35 serving as a first arm-side first stopper and a movable second stopper 36 serving as a first arm-side second stopper are provided on the front surface of the first arm. The movable-side first stopper 35 is provided on the right side in the circumferential direction of the hole 33 and on the outer peripheral side.
Is provided on the left side and the inner side of the hole 33 in the circumferential direction, that is, the two stoppers 35 and 36 are provided at positions diametrically displaced on both sides of the hole 33 in the circumferential direction. It is being done.

On the other hand, on the inner surface side of the housing 31 of the second arm 14, a fixed first stopper 37 serving as a first stopper on the second arm side and a fixed second stopper 37 serving as a second stopper on the second arm side. 38 are provided. Among them, the fixed side first stopper 37 is configured such that the third arm 15
When the arm 14 is rotated in one direction (clockwise direction in FIG. 1), it is located on the rotation path of the movable-side first stopper 35, and the movable-side first stopper 35 comes into contact with the arm 14. The rotation range on one side of the three arms 15 is mechanically restricted. In FIG. 1, the rotation trajectory of the movable-side first stopper 35 from the origin position of the third arm 15 to the contact with the fixed-side first stopper 37 is indicated by a.

The fixed-side second stopper 38 is provided at the movable-side second stopper when the third arm 15 rotates in a direction opposite to the second arm 14 (counterclockwise in FIG. 1). The third arm 1 is positioned on the rotation trajectory of the third arm 1 when the movable-side second stopper 36 abuts thereon.
The rotation range on the opposite side of 5 is mechanically regulated. In FIG. 1, from the origin position of the third arm 15,
The rotation trajectory of the movable second stopper 36 until it comes into contact with the fixed second stopper 38 is indicated by b. Therefore, the fixed-side first stopper 37 and the fixed-side second stopper 38
Are also provided at positions shifted in the diameter direction.

Further, at this time, the fixed-side first stopper 37 and the fixed-side second stopper 38 are provided such that the fixed-side first stopper 37 comes to a position shifted in the circumferential direction (the fixed-side first stopper 37 is on the left side in the figure). Have been. Therefore, when the third arm 15 rotates in one direction, the movable-side first stopper 35 comes into contact with the fixed-side first stopper 37 at a position passing the fixed-side second stopper 38 in the circumferential direction. It is becoming. Thus, the rotatable range of the third arm 15 with respect to the second arm 14 is mechanically restricted to the range indicated by B in FIG. 1 by the fixed-side stoppers 35 and 36 and the movable-side stoppers 37 and 38. It is like that.

Further, in this embodiment, a portion 31a of the housing 31 of the second arm 14 which overlaps with the hole 33 by the rotation of the third arm 15 is formed as a narrow portion 31a curved in a curved manner from the left and right. Have been. The robot controller is provided with a so-called software limit for restricting a rotation range of the third arm 15 with respect to the second arm 14 by software. A rotation range B regulated by the stoppers 35 to 38 is provided. Is slightly larger than the rotation range by the soft limit (for example, each is larger by 2 ° in both directions).

Next, the operation of the above configuration will be described. In the joint structure for connecting the second arm 14 and the third arm 15 described above, the housing 19 of the third arm 15 is used.
Since the wiring 34 passes through the inside of the hole 33 formed in the (end plate 23), the second arm 14
It is necessary to prevent the wiring 34 from being pinched between the edge of the hole 33 and the housing 31 of the second arm 14 due to the rotation of the third arm 15 with respect to.

Therefore, by providing a mechanical stopper mechanism in addition to the soft rotation range control in the robot controller, the second arm 1 of the third arm 15 is provided.
In this embodiment, when the third arm 15 rotates in one direction (clockwise direction in FIG. 1), the movable first stopper 35 moves to the fixed side. When the third arm 15 rotates in the opposite direction (counterclockwise direction in FIG. 1), the movable second stopper 36 is fixed to the fixed second stopper 38 when the third arm 15 rotates in the opposite direction (counterclockwise direction in FIG. 1). And the rotation range is regulated.

At this time, the positions of the two sets of stoppers 35 to 38 are displaced in the diametrical direction so that they are stepped, so that the track a of the movable-side first stopper 35 and the movable-side second stopper 36
And the fixed side first stopper 37 and the fixed side second stopper 38 are provided at positions also shifted in the circumferential direction, so that the third arm 15 rotates in one direction. At this time, the movable-side first stopper 35 comes into contact with the fixed-side first stopper 37 at a position passing the fixed-side second stopper 38 in the circumferential direction. As a result,
The rotation range B was able to be increased as compared with the rotation range A in the above-described conventional one.

By reducing the size of the hole 33 in the circumferential direction, the movable stoppers 35 and 36 on both sides can be provided closer to each other. It is considered that a rotation range equivalent to that of the present embodiment can be secured with the same configuration as that of the first embodiment. However, as described above, the hole 33 needs to have a function of allowing the connector at the tip of the wiring 34 to pass therethrough or permitting the wiring 34 to shift. Therefore, the hole 33 cannot be simply reduced in size.
If it is formed in a long hole shape in the diameter direction, the above function can be achieved, but then the entire joint becomes large in the diameter direction, which makes it impossible to meet the demand for the miniaturization of the robot. .

On the other hand, in the present embodiment, the hole 33 is provided in the shape of a long slot along the circumferential direction, so that the function required for the hole 33 is secured and the diameter of the hole 33 is maintained. Length in the direction, and thus the end plate 23 (end surface of the housing 19)
The diameter of the joint can be reduced, so that the joint can be prevented from increasing in size, and of course, the joint can be further reduced in size.

When the third arm 15 is rotated in one direction or the other direction to almost full with respect to the second arm 14, the hole 33 and the frame 31 of the second arm 14 overlap. However, in the present embodiment, the constricted portion 31 escapes from the frame 31 wrapping with the hole 33.
Since a is provided, the rotation range can be further widened as compared with the case where the portion is not constricted but straight.

As described above, according to the present embodiment, two sets of holes 33 are formed in the end plate 23 of the housing 19 on the outer periphery of the rotating body 28 (shaft) and serve as wiring passages. The positions of the stoppers 35 to 38 are displaced in the diametric direction so as to be stepped, so that the track a of the first stopper 35 and the second
Since the track b of the stopper 37 is displaced in the diameter direction, the hole 6 is restricted and the rotation range A of the arm 3 is reduced. There is an excellent effect that the rotation range B of the third arm 15 can be expanded while preventing the rotation.

Further, in the present embodiment, the hole 33 is provided in the shape of a long slot along the circumferential direction, so that the function required for the hole 33 is secured, Can be reduced in length, and thus the entire joint can be further reduced in size. Further, in the present embodiment, since the constricted portion 31a is provided in a portion of the housing 31 of the second arm 14 that overlaps with the hole 33, it is minimized that the hole 33 and the housing 31 of the second arm 14 overlap. The third arm 1
The rotation range B of the fifth arm 14 with respect to the second arm 14 can be further expanded.

The positions at which the fixed-side first stopper 37 and the fixed-side second stopper 38 are provided are not limited to the relationship described in the above embodiment, but may be set as necessary. The rotation range B in one direction and the opposite direction 15 can be freely set. In the above embodiment, the hole 33 has a long hole shape. However, the hole 33 may have a circular shape or the like as long as it fulfills a required function. Further, the constricted portion 31a is provided as necessary. What should I do?

In the above embodiment, the second arm 14
The present invention is applied to the joint that connects the first arm and the third arm 15. However, the same configuration can be adopted for other joints, and the overall arm of the robot body can be used. The present invention has been implemented by appropriately changing the configuration, the configuration of each arm, the arrangement of the servomotors, the configuration of the reduction gears, and other detailed configurations such as various modifications are possible without departing from the gist. What you get.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention and is a front view showing a configuration of a joint portion of a third arm.

FIG. 2 is a longitudinal sectional side view taken along line II of FIG. 1;

FIG. 3 is a front view showing the appearance of the robot body.

FIG. 4 is a diagram corresponding to FIG. 1 showing a conventional example.

[Explanation of symbols]

In the drawing, 11 is a robot body, 14 is a second arm (second arm).
15) are the third arm (first arm), 19
Is a housing, 21 is a 3-axis servomotor, 22 is a speed reducer unit, 23 is an end plate, 28 is a rotating body (shaft), 31
Is a housing, 31a is a constricted portion, 33 is a hole, 34 is a wiring, 35 is a movable-side first stopper (first arm-side first stopper), and 36 is a movable-side second stopper (first arm-side second stopper). , 37 are fixed-side first stoppers (second arm-side first stoppers), 38 is fixed-side second stoppers (second arm-side second stoppers), and B is a rotation range.

Continued on the front page (72) Inventor Yuji Kito 1-1-1 Showa-cho, Kariya-shi, Aichi F-term in DENSO Corporation (reference) 3C007 BS12 BT08 CV08 CW08 CX03 CX09 CY02 CY03 CY05

Claims (3)

[Claims] 1. A joint structure of a robot in which a second arm is relatively rotatably connected to a first arm by a shaft, wherein the joint is located on an outer periphery of the shaft of a housing of the first arm. In the part, while providing a hole forming a wiring passage,
A first arm-side first stopper and a second stopper are provided at diametrically shifted positions on both circumferential sides of the hole, and when the second arm rotates in one direction on the second arm, A second arm-side first stopper that abuts on the first arm-side first stopper to regulate the rotation range, and abuts against the first arm-side second stopper when the second arm rotates in the opposite direction. A joint part structure for a robot, wherein a second arm-side second stopper for restricting a rotation range in contact with the second arm-side second stopper is provided at a position shifted in a diametrical direction. 2. The joint structure for a robot according to claim 1, wherein the hole forming the wiring passage is provided in a long slot shape along a circumferential direction. 3. The housing according to claim 1, wherein a portion of the housing of the second arm, which overlaps the hole by the relative rotation of the second arm, is formed in a constricted shape. Robot joint structure.