JPH0829513B2 - Industrial robots - Google Patents

Description

TECHNICAL FIELD The present invention relates to an industrial robot having first and second pivotable arms.

[Conventional technology]

BACKGROUND ART Conventionally, an industrial robot called a horizontal articulated type is widely known. As a robot of this type, a first arm supported so as to be rotatable with respect to a base and a first arm are provided. It is generally provided with a second arm that can be turned with respect to the second arm, and a working member such as a chuck and a mechanism for operating the working member are attached to the tip of the second arm.

As a means for driving the arm, a speed reducer capable of obtaining a high speed reduction ratio in one stage is interposed between the arm supported rotatably and the drive motor, and a motor output of high rotation speed is provided in the power transmission system. There is one that decelerates with to convert to low speed and high torque before transmitting to the arm. By the way, in the combination of reduction gear and drive motor,
There are problems peculiar to the speed reducer, such as wear and vibration associated with backlash, and therefore, there has been a limit to speeding up the arm rotation speed and improving mechanical positioning accuracy.

Therefore, recently, the above-mentioned arm is directly driven by a high-torque direct drive motor (hereinafter referred to as a DD motor) in which a rotor is arranged between the stators having a double structure.
Drive-type robots have been developed and are attracting attention as ones that can solve the problems of low noise and maintenance-free operation, including high-speed and high-precision operation.

[Problems to be Solved by the Invention]

By the way, the first in the horizontal articulated robot
When trying to drive each of the arms and the second arm by the above DD motors, since the DD motors are relatively large, how to rationally deploy the two motors that drive both the above arms The problem remains in that respect.
That is, for example, the motor that drives the second arm
If it is attached to the tip of the arm, the moment of inertia of the swiveling portion increases, and the speeding up and accuracy of the operation are impaired. Further, if the motor is arranged to project above the arm, it becomes difficult to make the robot compact while ensuring a sufficient working range in the height direction below the arm turning portion.

In view of the above circumstances, the present invention provides a first arm and a second arm.
In each arm driven by a DD motor, it is possible to reduce the moment of inertia of the swiveling part and to secure a working range in the height direction below the swiveling part of the arm, and to have a compact structure. It is an object of the present invention to provide an industrial robot whose function can be improved.

[Means for solving the problem]

In order to achieve the above object, the present invention provides a first arm pivotally supported on a base, a second arm pivotable with respect to the first arm, and a second arm. Both of the motors are provided with a work member mounting portion provided at the tip of the arm, a first arm drive motor for driving the first arm, and a second arm drive motor for driving the second arm. Which are industrial robots each configured with a high torque direct drive motor,
The first arm drive motor is arranged on the base, and the second arm is formed smaller than the first arm drive motor.
The arm drive motor is coaxially disposed above the first arm drive motor, and the first arm is disposed above the second arm drive motor, and the arm drive motor is connected to the rotor of the first arm drive motor. The second arm drive motor is supported by the support member, and the first arm drive motor is connected to the first arm drive motor via the support member.
The second arm drive motor is connected to the turning shaft portion of the second arm via a transmission means provided in the first arm, and is connected to the support member to be connected to the inside of the first arm drive motor. The shaft body extending through the shaft is led out below the first arm drive motor, and the brake means is provided around the lower end of the shaft body in the base.

[Action]

According to the present invention, since the first arm drive motor and the second arm drive motor are installed on the base, the moment of inertia of the swiveling portion is smaller than that in the case where the motor is attached to the tip of the first arm. Get smaller.
Further, both motors are incorporated between the base portion and the base of the first arm in a state where the first arm is positioned at an appropriate height so as to secure a working space below the arm, The motor does not take up extra space above the arm.

Also, the first arm drive motor has a relatively large diameter and the second arm drive motor has a relatively small diameter due to the required drive torque, but the positional relationship of these motors below the first arm is lower. Large diameter first arm drive motor,
By disposing the small-diameter second arm drive motor on the upper side, it is advantageous for expanding the effective operating range when the distal end side of the second arm operates close to the proximal end side of the first arm, and The stability of the motor arrangement part is also improved.
The support member supports the second arm drive motor on the first arm drive motor and connects the first arm drive motor and the first arm.

Further, since the brake means for braking the first arm is provided in the base, an action of preventing unnecessary turning of the arm when the first arm drive motor is stopped is obtained, and the brake means is also compact. Laid out.

〔Example〕

An industrial robot according to an embodiment of the present invention will be described with reference to FIGS. 1 to 3.

In FIG. 1, reference numeral 1 is a cylindrical base, and a first arm drive motor 2 (hereinafter referred to as a first DD motor) composed of a direct drive motor is fixed to the upper surface thereof. Since the first DD motor 2 generates a high torque at a low rotation speed, a large-diameter outer stator 4 and a smaller-diameter inner stator 5 are coaxially arranged inside the housing 3 thereof. The rotor 6 is arranged between the children 4 and 5. An output flange 7 for extracting a rotational force is connected to the upper end surface of the rotor 6, and the output flange 7 is axially supported via a bearing 9 on the outer periphery of a hollow motor shaft 8 that supports the inner stator 5.

A cylindrical bracket 10 as a support member is connected to the upper surface of the output flange 7. This bracket
A hollow shaft 11 is connected to the center of the bottom surface of the hollow shaft 10. The hollow shaft 11 penetrates the inside of the motor shaft 8 coaxially, and its lower end is led out to the inside of the base 1.

The bracket 10 is erected vertically from the first DD motor 2 and also serves as a base mast, and the first arm 14 is fixed to the upper end of the bracket 10 via a cylindrical cover 13. The first arm 14 has a hollow box-shaped structure and extends horizontally. The first arm 14 is directly connected to the output flange 7 of the first DD motor 2 and pivots about an X axis passing through the axis of the motor shaft 8. To be done.

A cylindrical bracket 15 protruding downward is fixed to the lower surface of the tip of the first arm 14.
A hollow driven shaft 17 is rotatably supported inside the shaft 15 via a bearing 16. A second arm 18 is connected to the lower end of the driven shaft 17, and the second arm 18 has a hollow box-shaped structure and extends horizontally below the first arm 14. ing.

In addition, inside the cover 13, a second arm drive motor 20 (hereinafter, referred to as a second DD
(Referred to as a motor) is arranged. This second DD motor 2
The diameter of 0 is smaller than that of the first DD motor 2. That is, the first DD motor 2 needs to drive the first arm 12 against the moment of inertia of the entire turning portion, and a large driving torque is required, so the diameter is relatively large. The second DD motor 20 that drives the arm 18 has a relatively small diameter because the required drive torque is smaller than that of the first DD motor 2.

The second DD motor 20 has a cover 1 on the upper end of the bracket 10.
Fixed with 3. In this way, both DD motors 2 and 20 are coaxially stacked on the base 1 while the second DD motor 20 is positioned above the first DD motor 2 and supported by the bracket 10.

Then, in a state where the first arm 14 is arranged above the DD motors 2 and 20, the output flange 7, the bracket 10 and the cover 13 and other connecting members are connected to the first DD motor 2. The first arm 14 is connected.

Since the second DD motor 20 has the same configuration as the first DD motor 2, the same components are designated by the same reference numerals and the description thereof will be omitted.

The second DD motor 20 is connected to a driven shaft 17 which is a turning shaft portion of the second arm 18 via a transmission means including a belt 24 and the like mounted in the first arm 14. That is, the hollow drive shaft 2 is attached to the output flange 7 of the second DD motor 20.
1, the drive shaft 21 is located coaxially with the motor shaft 8, and the upper ends of the drive shaft 21 and the driven shaft 17 are led out into the first arm 14 and these shafts 21, A belt 24 is installed between pulleys 22 and 23 fixed to the lead-out end of 17. Therefore, the driving force of the second DD motor 20 is transmitted to the second arm 18 via the belt 24, and the second arm 18 is driven.
Is rotated about the Y-axis passing through the axis of the driven shaft 17.

The driven shaft 17 includes the first arm 14 and the second arm.
It is located at a substantially central portion of the overlapping portion of 18, and its upper and lower end portions open into the inner spaces of both arms 14 and 18.

At the tip of the second arm 18, a working member mounting portion for mounting and driving a working member such as an air chuck described later is provided. The working member mounting portion is, for example, as follows. It has a simple structure.

That is, a tubular casing 25 is provided at the tip of the second arm 18 so as to pass through in the vertical direction, and a cylindrical tubular body 26 is inserted through the bearing 27 inside the casing 25. Has been done. A hollow cylindrical ball spline shaft 29 is inserted inside the cylindrical body 26, and a movable cylinder 30 is coaxially connected to the lower end of the ball spline shaft 29. The movable cylinder 30 is a cylinder connected to the lower end of the casing 25.
It is led out from the lower end opening of 31, and a support shaft 33 is attached to this leading end. A ball screw 34 meshes with the inside of the ball spline shaft 29 from above, and the upper end of the ball screw 34 is connected to a servomotor 36 via a speed reducer 35 that can obtain a high reduction ratio in one step. . Therefore, when the ball screw 34 is rotated by the servo motor 36, the ball spline shaft 29 slides in the vertical direction, and the support shaft 33 moves up and down along the Z axis in the vertical direction.

Another servo motor 37 is accommodated inside the second arm 18 along a direction orthogonal to the ball spline shaft 29, and this servo motor 37 is connected via a speed reducer 38 which can obtain a higher reduction ratio. The bevel gear 39 is being driven. This bevel gear 39 meshes with another bevel gear 40 provided on the outer periphery of the ball spline shaft 29, and between the bevel gear 40 and the ball spline shaft 29, the ball spline shaft 29 is provided.
Although it is allowed to slide in the axial direction, there is a bearing member 41 for transmitting the rotation in the axial direction. Therefore, when the driving force of the servo motor 37 is transmitted to the ball spline shaft 29 via the bevel gears 39, 40 and the bearing member 41, the support shaft 33
Is rotated about the R axis along the direction around the ball spline shaft 29.

If the driving force of the servomotor 37 is transmitted to the support shaft 33 by using the bevel gears 39 and 40 in this way, this power transmission path can be compactly built around the motor shaft and the ball spline shaft 29. , Second arm 18
Can fit in the interior space of. Therefore, the bevel gear
It is possible to use it in a clean room without the oil splashing outward from the meshing parts of 39 and 40. Also,
On the contrary, foreign matter does not enter from the outside into the meshing parts of the bevel gears 39, 40, and it is possible to use it in a dust-covering work environment.

Further, in this embodiment, an air chuck 45 is attached to the support shaft 33. The air chuck 45 has an air introduction port 46 for opening the chuck and an air introduction port 47 for closing the chuck, and air hoses 48, 48 are connected to the introduction ports 46, 47, respectively. Air hose 48,
48 is introduced into the internal space of the second arm 18 through a through hole 49 provided in the lower surface of the tip of the second arm 18, and then passes through the inside of the driven shaft 17 into the internal space of the first arm 14. The drive shaft 21 and the second DD motor 2 are installed from here.
A connector provided on the peripheral surface of the base 1 through the inside of the 0 motor shaft 8, the bracket 10 and the hollow shaft 11 of the first DD motor 2.
Connected to 50. This connector 50 has external air pipes 51, 51 connecting the air hoses 48, 48 and the air supply source 53.
Opening valves 52, 52 are provided in these external air pipes 51, 51. Therefore, the air chuck 45 is opened / closed by selectively opening / closing the open / close valves 52, 52.

Also, the two servo motors 36 and 37 are computer
The rotation angle and rotation direction are controlled by commands from 55, and the origin position that serves as a reference for the vertical movement and rotation of the support shaft 33 is detected, including the signal code and power cord that send control signals to the motors 36 and 37. Proximity switch 58,59
The signal cord 56 from is connected to the connector 57 through the inside of both arms 14, 18 and DD motors 2, 20 as well as the air hose 48.

On the other hand, the hollow shaft 11 that rotates integrally with the rotor 6 of the first DD motor 2 has a sleeve 60 fixed to the lower outer peripheral portion led out into the base 1, and an encoder 61 is attached to this sleeve 60. ing. Encoder 61 is sleeve 60
A large number of magnetic poles are arranged at intervals on the outer periphery of the rotary plate 62 that rotates integrally with the rotary plate 62, and the rotational position of the rotor 6 is magnetically determined by detecting the magnetic poles with the sensor 61a. The signal from the encoder 61 is fed back to the first DD motor 2 via the computer 55 for magnetic pole control and rotational position control of the first DD motor 2.

The wiring (not shown) to the encoder 61 and the first DD motor 2 is guided to the connector 50 through the inside of the hollow shaft 11, and is connected to the computer 55 and the power supply 63 from here via external wiring.

A sensor device 64 for controlling the turning range of the first arm 14 is provided on the outer periphery of the lower end of the hollow shaft 11. This sensor device 64 includes projections 65a, 65b, 65c for position detection arranged on the outer peripheral surface of the lower end portion of the hollow shaft 11, and the projections 65a, 65c.
Proximity switches 66a and 66b for detecting b and 65c, and projections 65a to 65c or a ring 67 fitted and fixed to the outer peripheral surface of the hollow shaft 11, and the proximity switches 66a and 66b.
Are arranged radially with respect to the ring 67.

Then, as shown in FIG. 3, the first arm 14 makes a swivel motion of constant angles θ ₁ and θ ₂ from the origin position S, which is the reference of swivel, to both sides in the axial direction of the X axis.
65a is located at the origin position S, the projection 65b is located at the turning limit position A on one side, and the projection 65c is located at the turning limit position B on the other side. Further, the proximity switch 66b causes the ring 67 to project at the turning limit positions A and B.
The signals from the proximity switches 66a and 66b are fed back to the first DD motor 2 via the computer 55 for controlling the turning position of the first arm 14.

A sensor device 72 for controlling the turning range of the second arm 18 is provided inside the first arm 14. This sensor device 72 has substantially the same configuration as the sensor device 64 of the first arm 14, except that a ring 75 having a protrusion 73a for detecting the origin position of the second arm 18 has an upper end portion of the driven shaft 17. The ring 76 having the projections 73b and 73c for detecting the turning limit position of the second arm 18 is fixed to the upper end portion of the drive shaft 21, and accordingly, the proximity to detect the projections 73a to 73c. Switches 74a and 74b are provided separately around both shafts 17 and 21.

Further, the boss portion 23a of the pulley 23 on the driven shaft 17 has a second DD
Encoder 70 that detects the rotational position of the rotor 6 of the motor 20
Is installed with this encoder 70 or proximity switch
The wiring 77 to the 74a and 74b is guided from the inner space of the first arm 14 to the connector 57 through the insides of the second DD motor 20 and the first DD motor 2, and is connected to the computer 55 from here through the external wiring. .

In order to prevent overrun of the second arm 18 when some trouble occurs in the proximity switch 74b,
A stopper 79 made of rubber is provided on the bottom surface of the first arm 14, and a bolt 78 provided on the pulley 22 comes into contact with the stopper 79 when the second arm 18 exceeds the turning limit position. ing.

It also prevents the arm from moving unnecessarily and making contact with surrounding parts when the power supply to the motor is cut off due to power off or power failure, and in particular, it has a large turning radius (turning around the X-axis). In order to prevent the arm from unnecessarily turning along the locus K), a braking means 92 is provided for applying a braking force to the first arm 14 when the energization is cut off.

Since this brake means 92 takes up an extra space when incorporated in the upper part of a motor or the like, for example, the brake means 92 is provided around the lower end portion of the hollow shaft 11 inside the base 1 so as to be laid out compactly. There is.
That is, the braking means 92 includes a friction plate 80 formed in a flange shape on the outer periphery of the sleeve 60 that rotates integrally with the hollow shaft 11, and an air cylinder 82 supported inside the base 1 via a bracket 81. , A brake pad 84 made of synthetic resin attached to the tip of a piston rod 83a connected to the piston 83 of the air cylinder 82.
The brake pad 84 faces below the outer peripheral portion of the friction plate 80 and is constantly urged by the return spring 90 in a direction away from the friction plate 80. An air pipe 85 connected to the air cylinder 82 is connected to an external pipe 86 communicating with the air supply source 53 via a connector 50. A normally open solenoid valve 87 and a regulator are provided in the middle of the external pipe 86. 88 is provided, and the drive unit 89 of this solenoid valve 87 is a switch 91 that works in conjunction with a power switch (not shown) of the robot.
Connected to the power supply 63 via.

Further, in order to prevent overrun of the first arm 14 when some trouble occurs in the proximity switch 66b, a stopper 96 is fixed to the inner surface of the base 1 so that the first arm 14 moves in the turning limit position. Friction plate when exceeded
Bolts 95 provided on 80 come into contact with the stoppers 96.

According to the robot of this embodiment as described above, the first arm 14 is swung by the first DD motor 2 via the bracket 10 and the cover 13 and the second DD motor 2 in response to the control signal from the computer 55. At 20, the second arm 18 is swung via transmission means such as the belt 24, and the movement of these arms 18 causes horizontal movement and position adjustment of the air chuck 45. In addition, the servo motor 36,3
The air chuck 45 is moved up and down and rotated by driving 7, and the chuck opening / closing operation is performed by supplying / discharging air to / from the air inlets 46 and 47.

Various operations are performed by controlling these operations. In this case, the swing operation of both the arms 14 and 18 is performed by the DD motors 2 and 20 by the direct drive method, and both the DD motors 2 and 20 are stacked and arranged on the base 1. Since the moment of inertia of 18 is kept as small as possible, high speed operation and high accuracy are achieved.

Further, by stacking the two DD motors 2 and 20 coaxially and arranging the first arm 14 above them,
The first arm 14 is placed at a moderately high position,
A sufficient working range in the height direction is ensured by raising and lowering the air chuck 45 below the swiveling portion of 14,18. Moreover, the motor does not project above the arms 14 and 18, and the total height of the robot does not unnecessarily increase.

Furthermore, both DD motors 2 below the first arm 14
As for the positional relationship of 20, the first DD motor 2 having a relatively large diameter is located on the lower side, and the second DD motor 20 having a smaller diameter is located on the upper side, which is advantageous in expanding the effective operating range. That is, the upper portion of the motor-arranged portion below the first arm 14, which is closer to the arm, works when the distal end side of the second arm 18 is operated to a position closer to the base end portion of the first arm 14. It becomes a portion that interferes with the member mounting portion and limits the effective operating area, and the effective operating area is expanded as the diameter of this portion is made smaller.According to the present invention in which the second DD motor 20 having a small diameter is arranged on the upper side, This means that the effective operating area is expanded as compared with the case where the large diameter first DD motor 2 is arranged on the upper side.

〔The invention's effect〕

According to the industrial robot of the present invention described above, the first
Since the arm drive motor and the second arm drive motor are coaxially stacked and arranged on the base, and the first arm is arranged above the base, the operation speed and accuracy can be increased, and the arm can be formed. Place it appropriately high and secure a sufficient working range in the height direction below the arm turning part,
Moreover, the overall height of the robot is not unnecessarily increased, and a compact structure can be achieved.

In addition, the small second arm drive motor is arranged above the first arm drive motor arranged on the base, and the first arm is arranged above the small second arm drive motor, and is connected to the rotor of the first arm drive motor. Since the second arm drive motor is supported by the support member and the first arm is connected to the first arm drive motor, the arrangement is advantageous for expanding the effective operating area, and The support and the connection with the arm can be achieved with a simple structure. Further, since the braking means for braking the first arm is arranged in the base, it is possible to prevent unnecessary turning of the arm, and at the same time, the braking means can be laid out compactly.

[Brief description of drawings]

FIG. 1 is a sectional view of the entire robot according to an embodiment of the present invention, FIG. 2 is a view seen from the direction of the line II-II in FIG. 1,
FIG. 3 is a plan view showing the turning range of the arm. 1 ... Base, 2 ... 1st DD motor, 6 ... Rotor, 10
...... Bracket, 11 ...... Hollow shaft, 14 ...... First arm,
18 …… Second arm, 20 …… Second DD motor, 92 …… Brake means.

Claims (1)

[Claims] 1. A first rotatably supported with respect to a base.
Arm, a second arm that is rotatable with respect to the first arm, a working member mounting portion provided at a tip end portion of the second arm, and a first arm that drives the first arm. 1
An arm drive motor and a second arm that drives the second arm.
An industrial robot comprising an arm drive motor, each of the motors being a high torque direct drive motor, wherein the first arm drive motor is installed on the base, and the first arm drive motor The second arm drive motor formed in a small size is coaxially arranged above the first arm drive motor, and the first arm is arranged above the second arm drive motor.
The second arm drive motor is supported by a support member connected to the rotor of the first arm drive motor, and the first arm is connected to the first arm drive motor via the support member. For the second arm drive motor,
The rotating shaft portion of the second arm is connected via a transmission means provided in the first arm, while the shaft body connected to the supporting member and penetrating the inside of the first arm drive motor is connected to the first arm driving motor. An industrial robot, characterized in that it is led out below an arm drive motor, and brake means is provided around the lower end of this shaft body in the base.