JPH03125055A - Actuator for robot - Google Patents

Abstract

PURPOSE:To arrange a lead wire not to be on the outside of an arm by providing with a hollow part in a motor output shaft, and fixedly securing a cylindrical armature coil on the inner circumferential surface of a stator core through a permanent magnet and air gap. CONSTITUTION:Circular spline 3 is provided on the inner circumference of an actuator frame 1, and the output shaft of an actuator 32 is constituted. A motor output shaft is constituted on the inner circumference of flex spline 4, and provided with a cylindrical rotor yoke 8 having a hollow part 81. On the outer circumference of the rotor yoke 8, a permanent magnet 9 is fixed to constitute rotor. A stator core 10 is not provided with a slot to be mounted with a coil, and fixedly secured with an armature coil 11, therefore, loss can be reduced and the inner diameter can be increased by about 50%. Consequently, the outer diameter of the rotor yoke 8 becomes large and a plurality of lead wires can be set in the interior.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an actuator with a built-in reduction gear, and particularly to an actuator that drives joints of industrial robots and the like.

[Prior Art] Conventionally, in a harmonic reducer built into an actuator, a circular spline is provided inside the frame of the actuator via a bearing, and a cup-shaped flex spline is provided in contact with the inner circumference of the circular spline. A wave generator is provided on the inner periphery of the flex spline, and the input shaft of the harmonic reduction gear is fixed to the wave generator. This Is-
An actuator was constructed by connecting the input shaft of the monic reducer with the output shaft of a motor that drives the arm of the robot, and fixing the output shaft of the harmonic reducer to the arm of the robot. Publication No.).

Further, the motor coupled to the harmonic reducer is a fourth motor.
As shown in the figure, a wave generator 5 is placed inside a cup-shaped flex spline 4 that contacts the inner periphery of a circular spline 3, and a flange portion 13 is provided at the end of a frame 12 of a motor 6. There is one in which the actuator is fixed at 1 and the length direction of the actuator is shortened.

In the case of the actuator that drives the wrist installed at the end of the arm of an articulated robot, it is required that the actuator be built into each arm so as not to interfere with the movement of each arm. Connecting lead wires and the like are routed along the outside of the arm.

[Problems to be Solved by the Invention] Incidentally, the armature winding of a motor is generally fixed by being inserted into a slot provided in a stator core.

In this case, from the relationship between the stator core shape and the generated loss,
As a condition for minimizing the generated loss, the ratio of the inner diameter of the stator core lO and the outer diameter D0 shown in FIG. 5 is approximately 0. 5～
0. It is said to be in the range of 6. For example, the outer diameter is 10
When the diameter is 0 mm, the inner diameter D1 is approximately 60 mm. Since a permanent magnet 9 is provided inside the outer circumference of the output shaft 7 of the motor 6, the outer diameter of the motor output shaft 7 is approximately 20 to 30 mm.
It would be very difficult to make it hollow and pass the multiple lead wires connected to the motor of each arm in terms of strength and work.

Therefore, when wiring lead wires from the robot body to the motors installed on each multi-jointed arm, the wires must be routed along the outside of each arm, which not only restricts the movement of the arms and wrists, but also There were drawbacks such as the risk of causing a major accident if it came into contact with other equipment or workpieces.

The present invention eliminates restrictions on robot operation by changing the armature winding system of the motor, making the motor output shaft hollow, and passing the lead wire through the actuator so that it does not come out outside the arm. The purpose is to

[Means for Solving the Problems] The present invention provides a ring-shaped circular spline that is provided on the inner periphery of an actuator frame via a bearing and that fixes a load on an end face, and a ring-shaped circular spline that is provided in contact with the inner periphery of the circular spline. In the robot actuator, the actuator includes a flex spline, an elliptical wave generator provided in contact with an inner circumference of the flex spline, and a motor having a motor output shaft fixed to the wave generator. a motor frame disposed inside the wave generator; a motor output shaft fixed to the inner periphery of the wave generator and consisting of a cylindrical rotor yoke with a hollow portion; a permanent magnet fixed to the outer periphery of the rotor yoke; a stator core arranged to face the outer periphery of the magnet with a gap in between and fixed to the inner periphery of the motor frame; The robot actuator includes a cylindrical armature winding fixed to the motor frame, and a bearing supporting the rotor yoke on the motor frame.

[Function] On the inner circumference of the wave generator of the harmonic reducer,
A cylindrical rotor yoke that constitutes the motor output shaft is fixed, a permanent magnet is fixed to the rotor yoke to form a rotor, and a stator core arranged around the outer circumference has slots for mounting armature windings ( A cylindrical armature winding is fixed to the smooth inner surface of the stator core using resin or the like.

For this purpose, the inner diameter and outer diameter D0 of the stator core of the motor are
The ratio is approximately 0. 8 to 0.9, and if the outer diameter D0 of the stator core IO is constant, the inner diameter D can be increased by about 50% compared to a conventional stator core with slots.

Therefore, the inner diameter of the rotor yoke can also be increased. A hollow portion through which a plurality of lead wires can be passed can be provided in the rotor yoke.

Therefore, by passing the lead wire of the actuator provided at the tip of each arm into the hollow part of the actuator provided at the base of each arm, the lead wire of the actuator can be routed to the outside of each arm. There's no need to send it out.

[Example] The present invention will be described with reference to embodiments shown in the drawings.

FIG. 1 is a side sectional view of an embodiment of the present invention, in which a ring-shaped circular spline 3 is provided on the inner periphery of the actuator frame l via a bearing 2, and a hole 31 is provided on the outer end surface for mounting to fix the load. This constitutes the output shaft 32 of the actuator. Further, a silk hat-shaped flex spline 4 is provided in contact with the inner periphery of the circular spline 3, and a flange portion 41 of the flex spline 4 is fixed to the actuator frame 1. Furthermore, an elliptical wave generator 5 is provided on the inner periphery of the flexspline 4 and is brought into contact with the flexspline 4 via a bearing 42 . A cylindrical rotor yoke 8 having a hollow portion 81 and integrally forming the motor output shaft 7 of the motor 6 is fixed to the inner periphery of the wave generator 5 . A permanent magnet 9 that constitutes the field of the motor 6 is fixed to the outer periphery of the rotor yoke 8.
It constitutes a rotor. A cylindrical stator core 10 is arranged so as to face the outer periphery of the permanent magnet 9 with a gap therebetween,
A cylindrical armature winding 11 is provided on the inner peripheral surface of the stator core lO.
is fixed so as to face the permanent magnet 9 with an air gap in between. A silk hat-shaped motor frame 12 is provided between the outer periphery of the stator core IO and the flex spline 4, and the stator core IO is provided on the inner periphery of the motor frame 12.
is fixed, and the flange portion 13 is attached to the actuator frame l.
It is fixed to . Further, an anti-load side bracket 14 is provided on the flange portion 13 of the motor frame 12, an anti-load side bearing 15 that supports the anti-load side of the rotor yoke 8 is provided, and a rotation detector 16 directly connected to the motor 6 is fixed. has been done. A load-side bearing 17 is provided between the load-side end of the motor frame 12 and the wave generator 5, and the rotor yoke 8 is connected to the motor frame 12 via the wave generator 5.
supports the load side of the

Here, to explain the cylindrical stator core 10 and the cylindrical armature winding 11, the stator core 10 has no slots for mounting the armature winding, and as shown in FIG.
A cylindrical armature winding 11 is fixed to the smooth inner surface of the stator core IO with resin or the like.

In a stator with such a configuration, as a condition for minimizing the generated loss, the ratio of the inner diameter of the stator core IO to the outer diameter D0 is approximately 0. 8 to 0.9, and assuming that the outer diameter D0 of the stator core lO is constant, the inner diameter D1 is about 50% thicker than that of a conventional stator core with slots (it is possible to can.

Therefore, the outer diameter of the rotor yoke 8 can also be increased proportionally, so the rotor yoke 8 can be formed into a cylindrical shape and have a hollow part through which a plurality of lead wires can be passed. .

FIG. 3 shows an example in which the actuator for driving a multi-joint robot is built into the arm of the robot. That is, the lead wire L1 of the actuator C that drives the gripping device B provided at the tip of the arm A is passed through the hollow part of the rotor yoke of the actuator D that swings the gripping device B with respect to the arm A. Sent to the root of A. An actuator E is provided at the base of arm A to rotate the tip of arm A around the axis of arm A, and the lead wires of actuators C and D are connected to the hollow part of actuator E. Pass. An actuator F that swings the arm A is fixed to the tip of the arm G, and the lead wires, SL, and the wires of the actuators C1D and E are passed through the hollow part of the actuator F, and sent to the base of the arm G.

In this way, the lead wire of the actuator provided at the tip of each arm can be passed through each arm and the hollow portion of the actuator provided at the base.

In addition, it is possible to pass not only the lead wire of the actuator but also the fluid piping used for each arm and the tip.

[Effects of the Invention] As described above, according to the present invention, the lead wires of the actuators provided on each arm of an articulated robot can be wired inside each arm and at the base of the arm without being wired outside the arm. The wiring can be wired inside the hollow part of the actuator provided in the actuator.

Therefore, the operation of the arm and wrist mechanism is not obstructed by the lead wire (this has the effect of providing a highly reliable multi-jointed robot with a simple appearance).

[Brief explanation of the drawing]

FIG. 1 is a front sectional view showing an embodiment of the present invention, FIG. 2 is a front sectional view of a motor, and FIG. 3 is a front view of the motor as applied to an articulated robot, partially shown in cross section. FIG. 4 is a side sectional view showing a conventional motor, and FIG. 5 is a front sectional view of the conventional motor. l... Actuator frame, 2... Bearing, 3...
...Circular spline, 4...Flex spline, 41...Flange part, 42...Bearing, 5...
- Wave generator, 6... Motor, 7... Motor output shaft, 8... Rotor yoke, 81... Hollow part, 9... Permanent magnet, IO... Stator core, 11...
・Armature winding, 12...Motor frame, 13...
Flange part, 14... Anti-load side bracket, 15...
・Anti-load side bearing, 16... Rotation detector, 17... Load side bearing Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1. A ring-shaped circular spline that is provided on the inner periphery of the actuator frame via a bearing and fixes a load to the end face, and a flex spline that is provided in contact with the inner periphery of the circular spline. , an actuator for a robot comprising: an elliptical wave generator provided in contact with the inner periphery of the flex spline; and a motor having a motor output shaft fixed to the wave generator; a motor frame fixed to the inner periphery of the wave generator, a motor output shaft consisting of a cylindrical rotor yoke having a hollow portion, a permanent magnet fixed to the outer periphery of the rotor yoke, and an air gap around the outer periphery of the permanent magnet. a stator core arranged to face the permanent magnets and fixed to the inner periphery of the motor frame; and a cylinder fixed to the inner periphery of the stator core so as to face the permanent magnets with a gap in between. An actuator for a robot, comprising: an armature winding having a shape; and a bearing supporting the rotor yoke on the motor frame.