JPH089153B2 - Industrial robot arm - Google Patents

Description

Description: “Industrial field of application” The present invention relates to an arm of an industrial robot whose wrist is driven by a direct drive motor disposed inside, and is particularly suitable for coating work. Regarding the robot arm.

"Prior Art" Conventionally, an industrial robot capable of flexibly adapting to various works by changing an operation program has been used as an automatic machine for performing work such as painting and welding on behalf of a human.

By the way, when such an industrial robot is used in a flammable atmosphere, the robot main body has an explosion-proof structure (a special structure is used so that the atmosphere does not ignite even if sparks or the like are generated from the electrical components of the robot main body. It is indispensable.

Particularly in the painting work, since the robot body is placed in an atmosphere in which a solvent floats, conventionally, a hydraulic robot has been used because it is easy to realize an explosion-proof structure.

"Problems to be solved by the invention" However, since a hydraulic robot requires a hydraulic unit and it takes a great deal of time to manage oil, etc., an electric painting robot has recently been provided. It's coming.

However, in the case of the electric type, a large number of electric parts such as a motor or an electric wire for the electric field that are to be explosion-proof must be arranged in the robot body, so that the conventional electric painting robot has various types of explosion-proof structures. Had disadvantages.

That is, when the internal pressure explosion-proof structure is adopted as the form of the explosion-proof structure, a scavenging gas such as air is blown into the space in the robot body where the electrical components are arranged to apply an internal pressure, and the gas is exhausted to exhaust the space. The scavenging must be such that the outside atmosphere does not come into contact with the electrical items inside. However, the conventional internal-explosion-proof robot has the problems that the gas flow path is complicated, the pressure loss is large, the scavenging time is long, and the gas flow is apt to stagnant and the explosion-proof reliability is low. Was.

In particular, in a robot arm equipped with a wrist mechanism at its tip, in which a motor for driving the wrist mechanism is arranged, the above-mentioned problem is remarkable, and the scavenging gas is placed at the place where the motor is arranged. There has not been provided a device capable of efficiently flowing water.

The present invention has been made in view of the above conventional problems,
An arm of an industrial robot with an internal pressure explosion-proof structure that uses a direct drive motor that does not require a reducer, and provides explosion-proof protection for all motors at once with a single stream of scavenging gas. It is an object of the present invention to provide an arm of an industrial robot that can achieve the above and has a low flow path resistance for flowing scavenging gas.

[Means for Solving the Problems] The arm of the industrial robot according to claim 1 is provided with a wrist portion having a plurality of degrees of freedom at a tip portion, and a plurality of direct drives for driving the wrist portion in a base end portion. An arm of an industrial robot in which a motor is arranged in series on an axis, wherein the base end portion includes a rotor and a stator of at least one direct drive motor of the plurality of direct drive motors. In addition, an air chamber whose internal pressure is increased by introducing gas is provided, and the rotor included in the air chamber has a transmission member attached to one end of the rotor and protruding from the air chamber. The pressure receiving area on the transmitting member disposition side in the extending direction of the transmitting member is smaller than that on the non-disposing side, and the bevel gear is provided on the side of the transmitting member protruding from the air chamber. The bevel gear is provided and meshed with the bevel gear on the wrist side.

The arm of the industrial robot according to claim 2 is the arm of the industrial robot according to claim 1, wherein the base end portion includes a rotor and a stator of the plurality of direct drive motors. A chamber is provided, and the air chamber includes a plurality of motor chambers formed so as to respectively include the direct drive motor inside a hollow member that constitutes a body of the arm, and an axial line of the direct drive motor. Each motor chamber is made to communicate with the hollow portion included in the motor chamber through the gap, and the motor chambers are sequentially connected to the hollow portion included in the motor chamber adjacent to the motor chamber. It is characterized in that they are communicated with each other, whereby the air chamber forms a flow path that sequentially communicates the gap between the rotor and the stator.

Further, the industrial robot arm according to claim 3 is the industrial robot arm according to claim 1 or 2, wherein a surface of the base end portion is provided with a supply port that communicates with both ends of the flow path. A discharge port is provided.

Further, an industrial robot arm according to a fourth aspect is the industrial robot arm according to the first or second aspect, wherein the bearing forming the direct drive motor is arranged outside the flow path. It is characterized by that.

[Operation] According to the arm of the industrial robot of claim 1, the rotor included in the air chamber is provided with a transmission member protruding from the air chamber at one end thereof for transmission. Since the pressure receiving area on the transmitting member disposition side in the extending direction of the member is smaller than that on the non-disposing side, the pressure receiving area difference causes the pressure to be pushed toward the transmitting member side by the pressure in the air chamber. The bevel gear provided on the side of the working member that projects from the air chamber is pressed in the direction of the bevel gear on the wrist side that meshes with the bevel gear.

Further, according to the arm of the industrial robot of claim 2, since the air chamber includes the rotor and the stator and forms a flow path that sequentially connects the gaps between them, If the scavenging gas is blown into the room, the scavenging gas can be collectively flowed into the space where the rotor and the stator of each motor are arranged and the gap therebetween. Moreover, since the air chamber is composed of the chamber formed inside the hollow member forming the body of the arm and the hollow portion formed on the axis of the direct drive motor, the flow path resistance is reduced. , The pressure of the supplied scavenging gas can be lowered.

Further, according to the arm of the industrial robot according to the third aspect, only by connecting the pipes to the supply port and the discharge port provided on the outer surface of the arm, the scavenging gas is supplied to each motor to exert the explosion-proof effect. It is not necessary to install a hose inside the arm. Therefore, the piping work for the explosion-proof structure becomes very easy in the arm assembling process.

Further, in the arm of the industrial robot according to claim 4, since the bearing of the direct drive motor is not exposed to the flow of the scavenging gas, the lubricant of the bearing is not blown by the flow of the scavenging gas, resulting in poor lubrication. .

[Embodiment] An embodiment of the present invention will be described below with reference to FIGS.

In FIG. 1, reference numeral 1 as a whole is a robot body of an electric coating robot equipped with the arm of the present invention.

The robot body 1 includes a fixed base 2 which is a base member for installing the robot body 1, and a swivel which is provided on the fixed base 2 and is driven by a motor 3 to be rotated about an axis perpendicular to the installation surface. Base 4
A first arm 6 mounted on the upper part of the swivel base 4 and driven by a motor 5 to rotate about an axis parallel to the installation surface; and an axis line parallel to the installation surface at the tip of the first arm 6. The second arm 7 is rotatably mounted about the center of the arm, and the links 9 and 10 for transmitting the rotation of the motor 8 to the second arm to rotate the second arm.

Then, the robot main body 1 is controlled by the control device (not shown) to control the operation of the motor.
A painting gun attached to a wrist portion 11 having three axes provided at the tip of the arm is moved to a desired position and posture to perform painting work.

The second arm 7, which is an embodiment of the present invention, will be described in detail below with reference to FIGS.

FIG. 4 is a sectional view of the second arm 7. In the figure, reference numeral 12 is an arm body (hollow member) forming the body of the second arm 7. The arm body 12 is shown in FIG.
As shown in FIG. 4, it comprises a box-shaped portion 12a and a cylindrical portion 12b protruding from the box-shaped portion 12a and having the wrist portion 11 arranged at the tip thereof.

The inside of the box-shaped portion 12a of the arm body 12 is partitioned, so that the motor chambers 13, 14, 15 and the gas introduction chamber 16 are sequentially arranged on the axis of the arm body 12 as shown in FIG. Are arranged. The motor chamber 13 is open inside the cylindrical portion 12b. In addition, a wall that separates the motor chamber 13 and the motor chamber 14 from each other
17 or a wall 18 partitioning the motor chamber 14 and the motor chamber 15 is provided with openings 19 and 20 respectively located on the axis of the arm body 12.

The gas introducing chamber 16 is formed along the end surface of the box-shaped portion 12a, and the wall 21 that separates the gas introducing chamber 16 and the motor chamber 15 is located on the axis of the arm body 12. The opening 22 is formed. Further, holes 18a and 21a are formed in the walls 18 and 21 along the inner surface of the box-shaped portion 12a. Further, the gas introduction chamber 1 is provided on the end face of the box-shaped portion 12a.
A supply port 12c communicating with 6 is formed, and a discharge port 12d communicating with the inside of the motor chamber 13 is formed at a position on the side surface of the box-shaped portion 12a and close to the cylindrical portion 12b.

A motor 23 is arranged in the motor chamber 13 with its axis aligned with the axis of the arm body 12.

The motor 23 is a direct drive motor having a high torque characteristic at a low rotation speed, and as shown in FIGS. 2 and 3, the stator 24 is arranged concentrically with a gap 25 on the outside thereof. The rotor 26, a bearing 27 located near one end of the stator 24 and the rotor 26 and interposed therebetween to rotatably support each other, and the bearing 27 opposite to the one end. It is composed of an oil seal 28 which is disposed close to the side and seals between the stator 24 and the rotor 26, and a hollow portion 29 whose both ends are open is formed on the axis line thereof.

The rotor 26 of the motor 23 has a bearing for the oil seal 28.
A plurality of holes 30 for communicating the gap 25 between the stator 24 and the rotor 26 and the surface of the rotor 26 are provided at a position close to the side opposite to the side 27.

The motor 23 is arranged so that the bearing 27 side faces the wall 17 and the stator 24 is located at the periphery of the opening 19.
By fixing the stator 24 to the wall 17, the box-shaped portion 12
It is attached to a.

A motor 31 is arranged in the motor chamber 14 with its axis aligned with the axis of the arm body 12. Where the motor
Since 31 has the same structure as the motor 23, the same reference numerals are given to the constituent elements and the description thereof will be omitted. This motor 31
Like the motor 23, the bearing 27 side faces the wall 18 and the stator
24 are arranged so as to be positioned on the peripheral edge of the opening 20, and the stator 24 is fixed to the wall 18 so that it is attached to the box-shaped portion 12a.

A motor 32 is arranged in the motor chamber 15 with its axis aligned with the axis of the arm body 12. Where the motor
Since 32 has the same configuration as the motor 23, the same reference numerals are given to the constituent elements and the description thereof will be omitted. The motor 32 is arranged such that the bearing 27 side faces the wall 21 and the stator 24 is located at the peripheral edge of the opening 22, and the stator 24 is fixed to the wall 21 so that the box-shaped portion 12a. Is attached to.

On the axis of the arm body 12, a hollow shaft 33, which is a driving force transmission means for the wrist 11, and a hollow shaft (transmission member) 34.
And a shaft (transmission member) 35 is concentrically arranged.

Among these, the hollow shaft 33 is arranged at the outermost side, and the base end portion 33a thereof is fixed to the end portion of the rotor 26 of the motor 23. Further, the hollow shaft 34 is arranged between the hollow shaft 33 and the shaft 35, and the base end portion 34 a thereof is the hollow portion 2 of the motor 23.
It extends through the opening 9 of the wall 9 and the wall 9 and is fixed to the end of the rotor 26 of the motor 31. In addition, the shaft 35 is arranged on the innermost side, and the base end portion 35a thereof has a hollow portion 2 of the motor 23.
9, wall 19 opening 19, motor 31 hollow 29, wall 18 opening 20
Extends through and is fixed to the end of the rotor 26 of the motor 32. The rotor 26 to which the hollow shaft 34 is attached is
By mounting the hollow shaft 34, the hollow shaft 34
In the extending direction of the hollow shaft 34, the pressure receiving area on the side where the hollow shaft 34 is disposed is made smaller than that on the side where the shaft is not disposed. Similarly, the rotor 26 to which the shaft 35 is attached is The pressure receiving area on the side where the shaft 35 is arranged in the extending direction of the shaft 35 is made smaller than that on the side where the shaft 35 is not arranged.

Here, gaps 36, 37, 38 are formed between the base end portions 33a, 34a, 35a of each shaft and the stator 24 of each motor. An oil seal 39 is interposed between the hollow shaft 33 and the arm body 12 so that the interior of the motor chamber 13 and the interior of the cylindrical portion 12b do not communicate with each other. In addition, between the hollow shaft 33 and the hollow shaft 34 or the hollow shaft
Oil seals 40 and 41 are respectively interposed between the shaft 34 and the shaft 35, whereby the hollow portion 29 of the motor 23 and the inside of the hollow shaft 33, or the hollow portion 29 of the motor 31 and the hollow shaft 34. It does not communicate with the inside of the. Further, the base end portion 35a of the shaft 35 covers the hollow portion 29 of the motor 32.

As is clear from the above description, in the box-shaped portion 12a,
Gas introduction chamber 16, hollow part 29 of motor 32, motor chamber 15, motor 3
Hollow 29 of 1, motor chamber 14, hollow 29 of motor 23, motor chamber
13 are successively communicated with each other through the openings 22, 20, 19 or the gaps 36, 37, 38 or the gap 25 to form one air chamber 42.

Then, in the air chamber 42, for power supply or signal transmission, electric wires 43, 44, 45 which are inserted into the inside from the supply port 12c of the box-shaped portion 12a and connected to each motor are provided. There is.

That is, the electric wire 45 for the motor 32 is connected to the stator 24 of the motor 32 through the inside of the gas introducing chamber 16, and the electric wire 44 for the motor 31 is inside the gas introducing chamber 16 and the hole 21a formed in the wall 21,
It is connected to the stator 24 of the motor 31 via the inside of the motor chamber 15 sequentially. The electric wire 43 for the motor 23 passes through the inside of the gas introduction chamber 16, the hole 21a formed in the wall 21, the inside of the motor chamber 15, the hole 18a formed in the wall 18, and the inside of the motor chamber 14 in order. Connected to the stator 24 of the motor 23.

Here, packings 46 and 47 as shown in FIGS. 5 and 6 are attached to the holes 18a and 21a formed in the wall 21 or the wall 18, respectively. These packings 46, 47 are holes 46a, 47a for passing the electric wire 43 or the electric wire 44 in a sealed state.
Respectively, and seals between the electric wires 43, 44 and the holes 18a, 21a.

The wrist 11 includes a case 49 attached to the tip of a hollow shaft 33 supported in the cylindrical portion 12b by a bearing 48, and an axis of the arm body 12 supported by the case 49 via bearings 50 and 51. A case that can be rotated around orthogonal axes
52, and a gun mounting portion 55 which is supported by the case 52 via bearings 53, 54 and is rotatable about an axis parallel to the axis of the arm body 12 and forms a basic configuration.

The case 52 has a bevel gear 56 fixed to the tip of the hollow shaft 34, and the bevel gear 56 formed at the base end of the case 52.
The rotation of the hollow shaft 34 is transmitted by the bevel gear 57 that meshes with. Further, the gun mounting portion 55 is formed with a bevel gear 58 fixed to the tip of the hollow shaft 35, a bevel gear 59 arranged on the rotation center line of the case 52 and meshing with the bevel gear 58 at one end, and at the other end. A transmission shaft 61 having a bevel gear 60 formed therein and a bevel gear formed at the base end of the gun mounting portion 55 and meshing with the bevel gear 60.
The rotation of the shaft 35 is transmitted by 62.

In FIG. 4, reference numerals 70a, 70b, 71a, 71b, 72a, 72
What is shown by b is a stopper, which limits the movement range of each axis of the wrist.

Next, the second part of the painting robot configured as described above
The operation of the arm 7 will be described.

First, when the motor 23 operates, the hollow shaft 33 rotates together with the rotor 26, and the case 49 rotates together with the hollow shaft 33. The case 52 attached to the case 49 or the gun mounting portion 55.
The whole rotates around the axis of the arm body 12.

When the motor 31 operates, the hollow shaft 34 rotates together with the rotor 26, whereby the case 52 and the entire gun 55 attached to the case 52 rotate about an axis orthogonal to the axis of the arm body 12. To do.

When the motor 32 operates, the rotor 35 and the shaft 35
Rotates, which causes the gun mounting portion 55 to rotate about an axis parallel to the axis of the arm body 12.

Then, when the wrist portion 11 operates as described above, if the scavenging gas is sent to the supply port 12c at a predetermined pressure, the scavenging gas enters the air chamber 42 of the second arm 7 as follows. The flammable substances such as solvent in the atmosphere, which are introduced and circulated inside, are exhausted, so that the electric products (specifically, motors 23, 31, 32 or electric wires 43, 44, 45) in the second arm 7 The flammable substance is removed from a certain space, or the inflammable substance is prevented from entering the space, so that the flammable substance is prevented from igniting even if a spark or the like is generated from the electric article.

That is, the gas sent into the gas introduction chamber 16 from the supply port 12c flows into the hollow portion 29 of the motor 32 through the opening 22. Then, the gas flowing into the hollow portion 29 of the motor 32 flows into the motor chamber 15 through the gap 38, the gap 25 of the motor 32, and the through hole 30. Then, the gas flowing into the motor chamber 15 flows into the hollow portion 29 of the motor 31 through the opening 20, and further passes through the gap 37 and the gap 25 of the motor 31 through the hole 30 to pass through the motor chamber. Inflow into 14. Then, the gas flowing into the motor chamber 14 is
It flows through the opening 19 into the hollow portion 29 of the motor 23, further through the gap 36, through the gap 25 of the motor 23 and through the hole 30, into the motor chamber 13. And this motor room 13
The gas flowing in is discharged from the outlet 12d.

The arm 7 of the painting robot of this embodiment has the following effects.

First, at one end of the rotor 26 included in the box-shaped portion 12a,
Since the hollow shaft 34 protruding from the box-shaped portion 12a is attached, and the bevel gear 56 is provided on the side of the hollow shaft 34 protruding from the box-shaped portion 12a, the bevel gear 56 has a bevel gear 57 direction that meshes with the bevel gear 56. It is pressed by the gas pressure. Similarly, a shaft 35 protruding from the box-shaped portion 12a is attached to one end of the rotor 26 included in the box-shaped portion 12a, and a bevel gear 58 is provided on the side of the shaft 35 protruding from the box-shaped portion 12a. Therefore, the bevel gear 58 is pressed by the gas pressure in the direction of the bevel gear 59 meshing with the bevel gear 58. Therefore, the backlash between the bevel gears 56 and 57 and between the bevel gears 58 and 59 can be reduced.

Further, in the second arm 7, there is one air chamber 42 having a hollow portion 29 formed in each motor and a gap 25 between the stator 24 and the rotor 26 in order to communicate with each other and having a blow-through structure inside. Has been formed. The air chamber 42 is provided in the second arm 7.
A supply port 12c and a discharge port 12d are provided at both ends of the flow path formed by, and a scavenging gas is supplied to the supply port 12c to discharge the discharge port 12d.
It is possible to flow the scavenging gas without stagnation into the space where the three motors for driving the wrist portion 11 are arranged and the gap 25 thereof only by discharging the scavenging gas.

Therefore, there is an effect that explosion protection in the arm can be performed very efficiently and highly reliably.

In addition, since the flow path of the scavenging gas is large and very simple, the resistance of the scavenging gas is very small, and the pressure for supplying the scavenging gas can be lowered and the time required for the scavenging gas can be reduced. It has the effect of shortening,
There is an effect that the scavenging gas spreads sufficiently to each part.

Further, there is also an effect that the flow rate and the pressure of the scavenging gas may be managed collectively for all the motors.

Further, since it is not necessary to provide piping such as a hose for supplying scavenging gas inside, there is an effect that piping work during assembly is very easy.

Furthermore, the bearings 27 of each motor are arranged outside the flow path so that the bearings 27 are not exposed to the flow of scavenging gas. Therefore, the lubricant of the bearing 27 is not blown off by the flow of the scavenging gas, and the lubrication does not become defective.

[Advantage of the Invention] According to the arm of the industrial robot of claim 1, the rotor contained in the air chamber has a transmission member attached to one end of the rotor so as to project from the air chamber. Since the pressure receiving area on the transmitting member disposing side in the extending direction of the transmitting member is made smaller than that on the non-disposing side, the pressure receiving area difference causes the pressure in the air chamber to be pressed to the transmitting member side. The bevel gear provided on the side of the transmission member that projects from the air chamber is pressed in the direction of the bevel gear on the wrist side that meshes with the bevel gear. Therefore, backlash can be reduced.

Further, according to the arm of the industrial robot according to the second aspect, when the scavenging gas is blown into the air chamber, the scavenging gas is collectively contained in the space in which the rotor and the stator of each motor are arranged and the gap therebetween. Can be flushed. Therefore, there is an effect that the explosion protection inside the arm can be performed very efficiently and highly reliably. Moreover, since the flow path of the scavenging gas is large and very simple, the resistance of the scavenging gas is very small, the pressure for supplying the scavenging gas can be lowered, and the time required for the scavenging gas can be shortened. In addition to the effect, there is an effect that the scavenging gas sufficiently spreads to each part, and the explosion-proof reliability is further enhanced.

Further, according to the arm of the industrial robot according to the third aspect, only by connecting the pipes to the supply port and the discharge port provided on the outer surface of the arm, the scavenging gas is supplied to each motor to exert the explosion-proof effect. Therefore, there is an effect that the piping work for the explosion-proof structure becomes extremely easy in the arm assembling process.

Further, in the arm of the industrial robot according to claim 4, since the bearing of the direct drive motor is not exposed to the flow of the scavenging gas, the lubricant of the bearing is not blown by the flow of the scavenging gas, resulting in poor lubrication. Has the effect.

[Brief description of drawings]

1 to 6 are views showing one embodiment of the present invention,
1 is a perspective view of a robot body, FIG. 2 is a perspective view of a direct drive motor, FIG. 3 is a sectional view of a direct drive motor, FIG. 4 is a sectional view of an arm, FIG. 5 and FIG.
The figures are views showing packings. 7 ... Arm (second arm), 11 ... Wrist part, 12 ... Hollow member (arm body), 12c ... Supply port, 12d ... Discharge port, 13, 14, 15 ... Motor chamber, 23, 31,32 …… Direct drive motor (motor), 24 …… Stator, 25 …… Gap,
26 …… Rotor, 27 …… Bearing, 29 …… Hollow part.

Claims (4)

[Claims] 1. An industrial robot arm in which a wrist portion having a plurality of degrees of freedom is provided at a distal end portion, and a plurality of direct drive motors for driving the wrist portion are arranged in a base end portion in a continuous manner on an axis. There is provided, in the base end portion, an air chamber that includes a rotor and a stator of at least one direct drive motor of the plurality of direct drive motors and that has an internal pressure increased by introducing gas. The rotor contained in the air chamber has a pressure receiving member on the transmission member disposition side in the extending direction of the transmission member, with a transmission member protruding from the air chamber being attached to one end of the rotor. The area is smaller than the non-arranged side, a bevel gear is provided on the side of the transmitting member that projects from the air chamber, and the bevel gear is meshed with the bevel gear on the wrist side. Arm of the industrial robot according to claim. 2. An air chamber containing a rotor and a stator of the plurality of direct drive motors is provided in the base end portion, and the air chamber is a hollow member constituting a body of an arm. It is composed of a plurality of motor chambers formed so as to include the direct drive motors inside, and hollow portions formed respectively on the axes of the direct drive motors. Each motor chamber is included in the motor chambers. The air chamber is communicated with the hollow portion through the gap and is sequentially communicated with the hollow portion included in the motor chamber adjacent to the motor chamber, whereby the air chamber forms a gap between the rotor and the stator. The arm of an industrial robot according to claim 1, characterized in that it forms a flow path that is communicated in sequence. 3. The industry according to claim 1 or 2, wherein the surface of the base end portion is provided with a supply port and a discharge port that communicate with both ends of the flow channel. Robot arm. 4. The arm of an industrial robot according to claim 1, wherein the bearing forming the direct drive motor is arranged outside the flow path.