JPH08141968A - Wrist mechanism of industrial robot - Google Patents

Abstract

PURPOSE: To provide a wrist mechanism of an industrial robot wherein a rotating motor and an oscillating motor in a wrist mechanism are directly connected to each other without using an intermediate transmission means. CONSTITUTION: A wrist mechanism of an industrial robot is provided with a casing 3 for rotatably supporting a flange 4 to which a tool is to be attached, a rotating motor 32 for rotating the flange 4, an arm 2 for supporting the casing 3 so that the casing may be freely oscillated, and an oscillating motor 31 for oscillating the case 3. The rotating motor 3 is attached in the casing 3 and approximately coaxially connected to a rotary shaft 49 of the flange 4 thorough a speed reducing means 34, and the oscillating motor 31 is approximately coaxially connected to an oscillating shaft 38 of the arm 2 through a speed reducing means 34. Driving force of the rotating motor 32 and the oscillating motor 31 can be transmitted to the rotary shaft 49 and the oscillating shaft 38 through the speed reducing means 34, 44.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wrist mechanism that is rotatably attached to the tip of an arm of an industrial robot and has three degrees of freedom including this rotation.

[0002]

2. Description of the Related Art As a conventional example of this type of wrist mechanism, one shown in the schematic view of FIG.
-197387 or JP-A-3-208584). The wrist mechanism 100 is an arm 1 of an industrial robot.
02 is rotatably connected via a motor 103 and a speed reducer 104 as indicated by an arrow a. This wrist mechanism includes a rotating arm 10 that is rotatable with respect to the arm 102.
5, a casing 106 swingably connected to the rotating arm 105, and a flange 107 swingably connected to the casing 106 and to which a tool (not shown) is attached.

A deceleration means 109 and a pulley 110 are connected to a swing shaft 108 of the casing 106, and the rotating arm 1
The pulley 1 of the rotation motor 111 mounted in
A belt 113 is hung between 12 and the pulley 110. The driving force of the rotation motor 111 is pulley 112 → belt 113 → pulley 110 → reduction means 10.
9 is transmitted to the rotary shaft 108, and the casing 106 is swingable as indicated by an arrow b.

On the other hand, the rotating shaft 114 of the flange 107 is coaxially connected to the rotating motor 116 via the speed reducing means 115, and the flange 107 is rotatable as shown by arrow c. Then, the rotating shaft 117 of the arm 105 and the flange 1
The rotating shaft 114 of 07 is coaxial in the basic posture as shown in FIG. 5, and the swing shaft 108 is orthogonal to the rotating shafts 114 and 117 on the same plane.

On the other hand, the rotary shaft 1 of the flange 107
There is also known a wrist mechanism 101 as shown in FIG. 6 in which a space M is provided between the rotary shaft 117 and the rotary shaft 117 of the arm 105, and the swing shaft 108 is orthogonal to the rotary shafts 114 and 117. 5 is different from that shown in FIG. 5 in that the bevel gear 118 is used instead of the pulley and belt transmission means.
17 and the swing shaft 108 are made orthogonal to each other. And swing axis 1
The casing 106 is cantilevered with respect to 08.

[0006]

In the conventional wrist mechanisms 100 and 101 shown in FIGS. 5 and 6, the casing 106 is used.
The driving force of the swinging motor 111 for swinging the gear reaches the speed reducing means 109 via the belt transmitting means by the pulleys 110, 112 and the belt 113 or the gear transmitting means by the bevel gear 118. The belt transmission means and the gear transmission means are merely intermediate transmission means, and as compared with the case where the swinging motor 111 is directly connected to the speed reduction means 109, the probability of rattling or vibration is increased and the number of parts is increased. There was a problem that the assembling efficiency deteriorates.

The wrist mechanism 1 shown in either FIG. 5 or FIG.
Also in 00 and 101, the rotation motor 116 has the casing 106.
It is installed inside. Most of the weight of the casing 106 is occupied by the rotation motor 116, and considering the balance when the casing 106 swings, the swing shaft 108 is positioned so as to be positioned in the middle of the rotation motor 116 as illustrated.
Will be provided. Then, the protrusion length N of the casing 106 in the direction opposite to the flange 107 becomes long, and there is a problem that the welding cable, hose and the like that cross over the casing 106 are easily pinched by the protrusion portion.

The present invention has been made in view of the above problems of the prior art, and an object of the present invention is to provide an intermediate conduction means for both the rotating motor and the swinging motor in the wrist mechanism. An object of the present invention is to provide a wrist mechanism of an industrial robot that can be directly connected without using it, has a large space in the direction opposite to the flange of the casing, and has a cable that is not easily pinched.

[0009]

A wrist mechanism of an industrial robot according to the present invention which achieves the above object has a flange 4 to which a tool is attached, a casing 3 for rotatably supporting the flange 4, and the flange 4. A rotating motor 32 for rotating the casing 3, an arm 2 for swingably supporting the casing 3, and a swinging motor 31 for swinging the casing 3.
A wrist mechanism of an industrial robot comprising: a rotation motor 32 mounted in the casing 3 and connected to a rotation shaft 49 of the flange 4 via a reduction gear 44 in a substantially coaxial manner. The oscillating motor 31 is mounted in the casing 3 and is connected to the oscillating shaft 38 of the arm 2 through the speed reducing means 34 substantially coaxially.

The rotary shaft 49 and the swing shaft 38
Are orthogonal to each other on the same plane, and the rotation motor 32 and the swinging motor 31 in the casing 3 are mounted so as not to interfere on the same plane. 49 and the swing shaft 38 have a distance H.
In some cases, the rotating motor 32 and the swinging motor 32 in the casing 3 are mounted so as to overlap each other when viewed from the direction of the interval H.

[0011]

The rotating motor is mounted in the casing and is connected to the rotating shaft of the flange substantially coaxially via the speed reducing means. Similarly, the swinging motor is mounted in the casing. Since the arm is connected to the swing shaft of the arm substantially coaxially through the speed reducing means, the driving force of the rotating motor and the swing motor does not pass through the intermediate transmitting means but the rotating shaft or the swinging motor through the speed reducing means. Can be directly connected to the drive shaft.

The rotation shaft and the swing shaft are orthogonal to each other on the same plane, and the rotation motor and the swing motor in the casing are attached so as not to interfere with each other on the same plane. The wrist mechanism is of a type in which the pivot axis of the arm, the pivot axis of the flange, and the pivot axis intersect at one point. Further, the rotating shaft and the swing shaft are orthogonal to each other with a space,
If the rotation motor and the swing motor in the casing are mounted so as to overlap each other when viewed in the spacing direction, the rotation shaft of the arm and the rotation shaft of the flange are separated from each other, and the rotation shaft of the flange and the swing shaft are rocked. The wrist mechanism is of a type that intersects the axis at right angles.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a lateral sectional view of a wrist mechanism according to a first embodiment of the present invention, and FIG. 2 is a side view of a wrist mechanism according to the first embodiment of the present invention.

In FIG. 1, the wrist mechanism 1 includes a rotating arm 2 that is rotatable with respect to a fixed arm 11, a casing 3 that is swingable with respect to the rotating arm 2, and a casing 3. It consists of three parts of a rotatable flange 4. The rotating arm 2 of the wrist mechanism 1 is rotatably supported by a fixed arm 11, and the rotating arm 2 and the fixed arm 11 form a horizontal arm of an industrial robot. The horizontal arm is tiltably supported by a vertical arm (not shown) which is a tilting arm. The vertical arm is tiltably supported by a swivel base that can swivel with respect to the base. This type of industrial robot uses a vertical arm swing (S
1), tilting of the vertical arm (S2), tilting of the horizontal arm (S3), turning of the turning arm 2 of the wrist mechanism 1 (S4),
Swinging of the casing 3 of the wrist mechanism 1 (S5) and the wrist mechanism 1
The flange 4 has 6 degrees of freedom of rotation (S6).

The rotating arm 2 is rotatably supported by the fixed arm 11 via a motor 12, a speed reducer 13 and a rotating shaft 14 in a directly connected state. The base 15 of the rotating arm 2 has a cylindrical shape, but the base is torn into U-shapes to form left and right housing portions 16a and 16b.
A bearing 18a is fitted in the cylindrical portion 17a of the housing portion 16a, and a sleeve 17b is fitted in the housing portion 16b.
Is rotatably slidably fitted, and a bearing 18b is fitted in the sleeve 17b. The sleeve 17b and the housing portion 16b are fixed by a bolt 20 via a friction plate 19. The hole of the sleeve 17b for the bolt 20 is an arc-shaped long hole, and due to an excessive force, the sleeve 17b
b is slidable with respect to the housing portion 16b. Reference numerals 21 and 22 are lids for inspection.

The casing 3 includes a first cylindrical portion 25 rotatably supported by bearings 18a and 18b, and a first cylindrical portion 25.
The second cylindrical portion 26 projects at a right angle to the cylindrical portion 25 and forms a motor housing space inside. A bearing 27 is held by a pressing plate 28 at the tip of the second cylindrical portion 26. The flange 4 is rotatably supported by the bearing 27.

Next, the swing motor 31 and the swing motor 32 mounted in the motor housing space of the casing 3.
The drive structure of will be described. The swing motor 31 is fixed to the side plate portion 25b of the first cylindrical portion 25 with a bolt 33. A wave generator 34 of a harmonic speed reducer, which is a speed reducer, is fitted into the output shaft of the swinging motor 31, and the wave spline 39 bends the flex spline 39 in an elliptical shape, and the sleeve 17
The circular spline 35 disposed on the inner peripheral side of b is engaged with the circular spline 35, and the flex spline 39 is disposed on the side plate portion 25b of the casing 3.
It meshes with the spline 36. The driving force of the swing motor 31 is generated by the wave generator 34 and the circular
The orbital motion of the flexspline 39 between the splines 36 is converted, and the orbital motion of the flexspline 39 is transmitted to the rotary arm 2 via the circular spline 35.
As a result, the casing 3 swings relatively. That is, the wave generator 34 and the flexspline 3
9, the circular spline 35, and the circular spline 36 constitute a speed reducing means. The speed reduction means is not limited to the harmonic speed reduction mechanism, but may be a planetary speed reduction mechanism or a cyclo speed reduction mechanism. Further, reference numeral 38 is a swing shaft, and the speed reducing means 34, 39 ...
35 and 36 and a swinging motor 31 are attached.

On the other hand, the swinging motor 32 has the second cylindrical portion 26.
It is fixed by a bolt 42 to a ring portion 41 provided on the. A wave generator 44 of a harmonic speed reducer, which is a speed reducing means, is fitted into the output shaft of the swinging motor 32. The wave spline 45 bends the flex spline 50 into an elliptical shape, and the circular spline 45.・ 46 is engaged. The driving force of the swinging motor 32 is the flexspline 5 between the wave generator 44 and the circular spline 45.
The orbital motion of the flexspline 50 is transmitted to the flange 4 via the circular spline 46, so that the flange 4 relatively rotates.
That is, the wave generator 44, the flexspline 50, the circular spline 45, and the circular spline
The spline 46 constitutes a speed reducer. The speed reduction means is not limited to the harmonic speed reduction mechanism, but may be a planetary speed reduction mechanism or a cyclo speed reduction mechanism.

Since there is nothing in the rotating arm 2, a wall 29 is formed near the root 15. Figure 2
As shown in FIG.
b, and has a vertically symmetrical shape of the rotating shaft 14. And, as shown in the figure, the casing 3 is 40 ° to 3 °
Controlled rocking in the range A up to 20 ° is possible.

Next, the operation of the wrist mechanism 1 described above will be described below. By the controlled drive of the motor 12, the rotating arm 2 rotates about the rotating shaft 14 in a predetermined rotation (S
4) is possible. Then, by the controlled drive of the swinging motor 31, a predetermined swinging (S5) about the swinging shaft 38 of the casing 3 is performed in a direct connection state only via the speed reducing means 34, 35, 36. Further, by the controlled drive of the rotation motor 32, the rotation shaft 4 of the flange 4 is rotated.
The predetermined rotation (S6) about 8 is the speed reducing means 44, 4
It is performed in a direct connection state only through 5,46. Eventually, the wrist mechanism 1 has three degrees of freedom when directly connected to the motor, and there is no intermediate transmission means from the motor to the speed reduction means. The absence of this intermediate conduction means eliminates rattling and vibrations due to the intermediate conduction means, reducing the number of parts and the number of assembly steps.

Further, the rotating shaft 14 of the rotating arm 2 and the rotating shaft 49 of the flange 4 are located on the same straight line in the basic posture as shown in FIG. 49
The wrist mechanism 1 has a straight shape and is compact, and is orthogonal to the same plane. Further, since the rotating motor 32 and the swinging motor 31 are arranged in a T-shape inside the casing 3, there is nothing inside the rotating arm 2, and the first cylindrical portion 25 of the casing 3 and the wall 29. A sufficient space is secured between and. Therefore, it is less likely that welding cables, hoses, and the like that cross over the casing 3 will be caught between the rotating arm 2 and the casing 3 due to the swinging of the casing 3.

Next, a second embodiment of the present invention will be described with reference to the drawings. FIG. 3 is an external view of a wrist mechanism according to a second embodiment of the present invention, and FIG. 4 is a sectional view of a main part of a wrist mechanism according to the second embodiment of the present invention. The parts different from the first embodiment shown in FIGS. 1 and 2 will be mainly described.

FIG. 3A is a side view of the wrist mechanism 10, and FIG. 3B is a view of the wrist mechanism 10 taken along arrow X in FIG. Also,
4A is a sectional view taken along the line YY of FIG.
(B) is a ZZ sectional view of FIG. In the figure, the rotating arm 2 is long, and the swing shaft 38 of the rotating arm 2 and the rotating shaft 49 of the flange 4 are provided orthogonally with a space H. Then, the swinging motor 31 and the swinging motor 32 in the casing 2 are vertically overlapped with each other in a space H. As a result, the thickness of the casing 3 in the vertical direction is increased, but the length is shortened.

That is, the casing 3 is the rotation motor 3
1 has a shape in which the center of the second cylindrical portion 52 for accommodating the swinging motor 32 is vertically displaced from the first cylindrical portion 51 for accommodating the first cylinder 51 so that the centers thereof are orthogonal to each other. ing. The mechanism by which the rotating motor 32 rotates the flange 4 is the same as that described in FIG. 1, and the mechanism by which the swing motor 31 swings the casing 3 is also the same as that described in FIG. Therefore, the wrist mechanism 10 also has the advantage that the swinging motor 31 as well as the swinging motor 32 is directly connected.
As described above, the present invention is also applicable to a type in which the swing shaft 38 of the rotary arm 2 and the rotary shaft 49 of the flange 4 are orthogonal to each other with a distance H. This type of wrist mechanism 10 is suitable as a wrist mechanism for an industrial robot that works in a narrow space by reducing the diameter of the flange 4 and attaching a small tool to the flange 4.

Further, as shown in FIG. 4, the rotary arm 2 is provided with a conical recessed wall 53, and the wall 5 is provided.
There is a sufficient space between the casing 3 and the casing 3, and there is little possibility that welding cables, hoses, etc. that cross over the casing 3 will be caught between the rotating arm 2.

[0026]

The industrial robot wrist mechanism of the present invention is
Since both the flange rotating motor and the casing swinging motor are mounted in the casing, they do not project outside the rotating arm 2 along the line of the swinging shaft 38, and the rotating motor and swinging motor are It is possible to connect the rotary shaft and the swing shaft without using the intermediate transmission means, eliminate rattling and vibration due to the intermediate transmission means, reduce the number of parts, and reduce the number of assembly steps. Further, since the rotation motor and the swing motor are attached to the casing, there is no motor in the arm that swingably supports the casing, and the space between the casing and the flange side is enlarged, or the casing By rounding the shape on the side opposite to the flange, it becomes possible to prevent the welding cable, hose, etc. that cross over the casing from being caught between the casing and the arm.

Further, a wrist mechanism of a type in which the pivot axis of the arm, the pivot axis of the flange and the pivot axis intersect at a single point, or the pivot axis of the arm and the pivot axis of the flange are separated from each other to pivot the flange. This is a highly flexible wrist mechanism that can be applied to any type of wrist mechanism in which the axis and the swing axis are orthogonal to each other.

[Brief description of drawings]

FIG. 1 is a lateral sectional view of a wrist mechanism according to a first embodiment of the present invention.

FIG. 2 is a side view of the wrist mechanism according to the first embodiment of the present invention.

FIG. 3 is an external view of a wrist mechanism according to a second embodiment of the present invention.

FIG. 4 is a sectional view of a main part of a wrist mechanism according to a second embodiment of the present invention.

FIG. 5 is a schematic view of a wrist mechanism according to a first conventional example.

FIG. 6 is a schematic view of a wrist mechanism according to a second conventional example.

[Explanation of symbols]

 1, 10 Wrist mechanism 2 Rotating arm (arm) 3 Casing 4 Flange 11 Fixed arm 14 Rotating shaft 31 Swinging motor 32 Swinging motor 34 Wave generator 35 Circular spline 36 Circular spline 38 Swinging shaft 44 Wave Generator 45 Circular spline 46 Circular spline 49 Rotation axis

Claims (3)

[Claims] 1. A flange 4 to which a tool is attached, a casing 3 for rotatably supporting the flange 4, a rotating motor 32 for rotating the flange 4, and a casing 3 for swingably supporting the casing 3. A wrist mechanism of an industrial robot having an arm 2 and a swinging motor 31 for swinging the casing 3, wherein the rotating motor 32 is mounted in the casing 3, and a deceleration means 44 is provided. Is connected to the rotary shaft 49 of the flange 4 substantially coaxially, the swinging motor 31 is mounted in the casing 3, and is substantially coaxial with the swinging shaft 38 of the arm 2 via the speed reducing means 34. Wrist mechanism of an industrial robot characterized by being connected. 2. The rotation shaft 49 and the swing shaft 38 are orthogonal to each other on the same plane, and the rotation motor 32 and the swing motor 31 in the casing 3 do not interfere on the same plane. The wrist mechanism of the industrial robot according to claim 1, wherein the wrist mechanism is attached as follows. 3. The rotation shaft 49 and the swing shaft 38 are orthogonal to each other with a gap H, and the rotation motor 32 and the swing motor 32 in the casing 3 are in the direction of the gap H. The wrist mechanism of the industrial robot according to claim 1, wherein the wrist mechanism is attached so as to overlap with each other when viewed from above.