JP2599188B2 - Electric robot - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric robot, and more particularly, to a motor case in which a motor is housed and a space inside the robot which is sealed, and the space has an internal pressure structure of a predetermined pressure. Related to electric robots.

2. Description of the Related Art Conventionally, various types of electric robots in which each movable part is driven by a motor have been developed.

Since this type of electric robot has a structure in which each movable part is driven by a motor, it is necessary to use an explosion-proof structure when used in, for example, a highly flammable atmosphere. For example, in an electric robot for painting which sprays a flammable paint, it is considered that an electric system in which sparks easily occur has an internal pressure explosion-proof structure.

As an internal pressure explosion-proof structure employed in a conventional electric robot, there is the following structure. As disclosed in, for example, Japanese Utility Model Publication No. 61-175389, a motor is housed in a sealed motor case, and a cable for supplying power to a terminal box and a cable for connecting the terminal box to each motor are provided. There is an internal pressure explosion-proof structure in which a protective gas of a predetermined pressure is supplied into the inside of a tube having a sealed structure and a motor case, and when the gas in the tube leaks and the pressure drops, the power supply is cut off.

Further, there is an internal pressure explosion-proof structure in which a sealed internal pressure chamber is provided in an arm and a plurality of motors are housed in the internal pressure chamber.

However, in the internal pressure explosion-proof structure employed in the above-described conventional electric robot, since the tubes connected to the respective motors protrude to the outside in a slack state, the movable parts operate. However, there is a problem that the tube is likely to be caught by other devices or protruding objects in the surroundings. In addition, in the case of (1), since each tube needs to be equal in number to the number of motors, the number of tubes is large, and the operation of connecting the tubes is complicated, and the possibility of connection error is high.

In the above case, since a plurality of motors are arranged in the internal pressure chamber provided in the arm, the moment of inertia of the arm becomes extremely large depending on the position of the internal pressure chamber, and the operation accuracy of the arm is significantly reduced. Inconveniences such as
Further, there is a problem that it is difficult to perform maintenance of the motors, and it is not possible to assemble each motor as a single unit at the time of assembly, which leads to a reduction in production efficiency.

Therefore, an object of the present invention is to provide an electric robot that has solved the above-mentioned problems.

Means for Solving the Problems The present invention provides an electric robot configured to rotatably support a movable portion on a fixed base and drive the movable portion by a motor housed in a motor case, A sealed space is formed inside each of the base, the movable part, and the motor case. The motor case is sealed by a flange coupled to the fixed base and the movable part, and the motor is connected to the flange. A connector connected to the fixed base and the movable part, and a cable connected to the connector is mounted in a space of the fixed base and the movable part, and the fixed base and the movable part are provided. Gas is supplied into the space portion from the space portion of the motor case and the ventilation hole of the flange, and the inside of each space portion is maintained at a predetermined pressure. .

According to the present invention, since the connector and the ventilation hole are provided on the flange that seals the motor case, the motor case with the built-in motor can be mounted when the motor is mounted. Can be easily performed. Further, the cables and tubes do not protrude to the outside of the robot in a slack state, so that when the robot operates, the cables and tubes do not get caught by peripheral devices or protrusions. Furthermore, since multiple cables can be routed collectively using the connector provided on the flange,
The wiring work of the cable can be easily performed, and the malfunction due to the incorrect connection of the cable can be prevented.

In addition, since the supply of the protective gas can be performed using the motor case having a small pressure loss or the internal space of the robot movable part,
Protective gas exchange can be performed in a short time, and the pressure in the motor case and the space of each movable part is kept below the atmospheric pressure, effectively preventing dust generated in the robot from being discharged into the clean room. Therefore, the present invention can be applied to a robot used in a clean room.

Embodiment FIGS. 1 to 3 show an embodiment of an electric robot according to the present invention.

In each of the figures, the electric robot generally includes a fixed base 1, a horizontal turning portion 2 rotatably provided on the fixed base 1, a support 3 standing up from the horizontal turn 2, and an arm supported on the upper end of the support 3. 4

5 is a motor unit for driving the horizontal swivel unit 2 in the arrow theta ₁ direction, provided on the fixed base 1. 6 is a motor unit for driving the column 3 in the arrow theta ₂ direction, it is provided on the side surface 2a of the horizontal swivel unit 2. A motor unit 7 for driving the arm 4 in the direction of the arrow θ _{3 is} provided at the upper end of the support 3.
And a motor unit 8 for driving a wrist mechanism is provided at a rear portion of the arm 4. Wrist mechanism provided at the tip of the arm 4 9 arrows theta _4, theta _5, first to rotate the theta ₆ direction, the second, third rotating portion 9a, 9b, have 9c, the The motor unit 8 accommodates three motors (shown in FIG. 3) for driving the rotating parts 9a, 9b, 9c.

Each of the motor units 5, 6, 7, 8 has a motor case 5a, 6a, 7a, 8a having a sealed structure, and the motor case 5a, 6a, 7a, 8a Part 2, strut 3,
An internal pressure explosion-proof structure to be described later is formed together with each internal space of the arm 4. As shown in FIG. 2, the motor unit 5 on the fixed base 1 has a connector 12 with a tube 12 through which cables 10 (10 ₁ to 10 ₆ ) connected to the respective motors for the θ _{1 to} θ ₆ directions are inserted. Connected through. A motor 14 and a differential eccentric reduction gear (hereinafter referred to as a reduction gear) 15 for reducing the rotation of the motor 14 are housed in the case 5a of the motor unit 5, and the reduction gear 15 is mounted on the flange 5b of the motor unit 5. Fixed. The shaft 15a of the speed reducer 15 is supported by a bearing 17 and hermetically sealed with the fixed base 1 by an oil seal 18. A gear 15b is provided at the tip of the shaft 15a, and the gear 15b meshes with a gear 2c provided at the lower part of the horizontal turning section 2. Thus, the gear 15b after rotation of the motor 14 whose speed is reduced by the reduction gear 15 is transmitted to the horizontal swivel part 2 through 2c, the horizontal swivel unit 2, a post 3, in the horizontal direction (arrow theta ₁ direction) together with the arm 4 Rotate.

Another cable 10 ₂ to 10 ₆ with the exception of the cable 10 ₁ connected to the motor 14 is inserted into the space portion 1a formed as a cable passage in the fixed base 1 via a connector 16. This space 1a extends horizontally like a duct and extends horizontally.
Is connected to the hollow portion 2b of the
The oil seal 20 hermetically seals the gap between the air gap and the hollow portion 2b. Therefore, the cable 10 (10 ₂ to 10 ₆ ) passes through the space 2d formed in the hollow portion 2b of the horizontal turning portion 2, and
It is inserted into the motor case 6a of the motor unit 6 for driving the support column via the connector 22.

The motor case 6a houses a motor 23 and a speed reducer 24 for reducing the rotation of the motor 23. Another cable 10 ₃ to 10 _6, except for the cable 10 ₂ connected to the motor 23 is inserted into the upper space 2e of the horizontal turn portion 2 via a connector 26 provided in the flange portion 6b of the casing 6a. This upper space 2e
And the above-mentioned space 2d are defined by a partition 2f.

The output shaft 31 of the speed reducer 24 is connected to a shaft 32 of the column 3 via a coupling 28, and the shaft 32 is fixed to a flange 33 in the column 3. Note that the shaft 31 is supported by a bearing 25, and the space between the shaft 31 and the horizontal turning portion 2 is sealed by an oil seal 27.
An annular shaft 3b having a hollow portion 3a protrudes laterally from the lower end of the column 3. The shaft 3b and the horizontal turning portion 2 are sealed by an oil seal 29, and the shaft 3b is supported via a bearing 30.

With the inside the hollow portion 3a the shaft 32 is inserted, the cable 10 ₃ to 10 ₆ from the upper space 2e is inserted. Further, the cable 10 ₃ to 10 ₆ is inserted into the case 7a of the motor unit 7 provided on the upper end side of the column 3 via the connector 34 is mounted to the space portion 3d along the inner wall 3c of the strut 3 You.

A motor 35 for driving the arm 4 is provided in the case 7a.
The reduction gear 36 is housed, and the shaft 36a of the reduction gear 36 is housed.
A bearing 37 and an oil seal 38 are provided between the support 3 and the support 3. This shaft 36a is connected to the shaft 40 of the arm 4 via a coupling 39. Also, shaft
The shaft 40 is inserted into the hollow portion 4b of the shaft 4a projecting from the side surface of the arm 4, and the shaft 4a is supported by a bearing 41.
The space between the shaft 4a and the support 3 is sealed by an oil seal 42.

Arm other cables 10 ₄ to 10 _6, except cables 10 ₂ connected to the motor 35 through the hollow portion 4b of the upper space portion 3e and shaft 4a of the arm 3 via the connector 43 from the casing 7a 4
Is inserted into the space 4c. The upper space of the arm 3
3e is defined by the space 3d of the column 3 and the partition 3f.

As shown in FIG. 3, the arm 4 is connected via the connector 43.
The cable 10 ₄ -10 ₆ inserted into the space portion 4c of the motor 44 for driving the respective rotation portions 9a of the wrist mechanism 9 is inserted into the case 8a of the motor unit 8, 9b, and 9c through the connector 43 ' ~
Connected to 46. Also, as described above, a plurality of cables 10 ₁
10 to ₆ are fixedly mounted on the fixed base 1, the horizontal revolving unit 2, the support 3, and the respective spaces 1a, 2b, 2c, 3d, 3e, and 4c in the arm 4, and the case of each motor unit 5 to 8 Since it is inserted in 5a-8a, it is not exposed at all outside the electric robot. Therefore, in the electric robot described above, the occurrence of an accident such as a cable, a tube, or the like that is slackened outside and gets caught in a peripheral device or the like when the movable portions operate as in the related art is completely prevented. Also, the wiring work is completed only by connecting the cables 10 ₁ to 10 ₆ to the respective cases 5a to 8a via the connectors 12, 16, 22, 27, 34, 43, 43 '. Wiring is easier and more efficient than connecting. Further, since the motor units 5 to 8 can be removed simply by removing the connectors, maintenance work such as maintenance and inspection is easy.

The motors 44 to 46 are provided in the case 8a of the motor unit 8.
In addition, although reduction gears 47 to 49 for reducing the rotation of each of the motors 44 to 46 are provided, since the balance with the wrist mechanism 9 is maintained, the inertia moment is small and no operation error occurs. .

The shafts 47a to 49a of the speed reducers 47 to 49 have bevel gears 50 to 52 at their ends, and the bevel gears 50 to 52 are connected to the wrist mechanism 9.
The bevel gear 53c of the cylindrical shaft 53, the bevel gear 54a of the cylindrical shaft 54, and the bevel gear 56 of the shaft 55 for transmitting the rotational driving force to the respective rotating parts 9a, 9b, 9c
Are engaged with each other. Therefore, the motors 44 to 46
53, 54, each of the rotating parts 9a, 9b, 9c via the shaft 55 and the like with arrows θ ₄ ,
Drive in the θ ₅ and θ ₆ directions. In addition, between the output shafts 47a to 49a and the wall of the arm 4, bearings 57 to 59 for bearing the output shafts 47a to 49a and an oil seal 60 for hermetically sealing the two are provided.
To 62 are provided. Further, the case 8a of the motor unit 8 has a hole 8b, but since the hole 8b is closed by the stopper 8c, the inside of the case 8a has a closed structure.

The cylindrical shaft 53 is supported by bearings 65, 66 on partition walls 63, 64 including the space 4c of the arm 4, and supports 63, 64 on the support portion.
Oil seals 67 and 68 are provided to hermetically seal between the spaces 64. Therefore, the space 4c in the arm 4 also has a closed structure.

Here, before describing the flow of the protective gas related to the internal pressure explosion proof of the electric robot having the above configuration, the details of each of the motor units 5, 6, 7, and 8 will be described with reference to FIGS. 4 and 5. explain.

Since the motor units 5, 6, 7, and 8 have substantially the same configuration, the motor unit 7 that drives the arm 4 will be described here as an example.

As shown in FIGS. 4 and 5 in an enlarged manner, the motor 35 and the speed reducer 36 are housed in the case 7a of the motor unit 7 as described above.
Are stored, and the speed reducer 36 is fixed to the flange 7b.

The center shaft insertion hole is provided in the flange 7b of the case 7a.
A pair of vent holes 69 and 70 in addition to the protection gas 7b ₁ passes is drilled. One vent hole 69 is provided below the speed reducer 36, and the other vent hole 70 is provided above the speed reducer 36, and the protective gas enters the case 7a from the lower vent hole 69 as shown by the arrow in FIG. It is supplied, fills the case 7a, and flows out from the upper ventilation hole 70.

In addition to the vent holes 69 and 70, the flange 7b has a bolt insertion hole 71 for mounting the motor unit 7 on the support column 3, a bolt insertion hole 72 for mounting the speed reducer 36, and a connector half 34a of the connectors 34 and 34. , 43a are inserted. The flange 7b has a stepped portion 76 for mounting an oil seal 75 on the peripheral edge thereof for hermetically sealing the space between the column 3 and the flange 7b.

The connector halves 34a and 43a are connected to connector halves 34b and 43b (shown by dashed lines in FIG. 4) connected to the cable 10.

Here, supply of the protective gas in the electric robot having the above configuration will be described.

As shown in FIG. 2, a gas supply hole 5c is formed in the upper part of the case 5a of the motor unit 5, and the protective gas is provided in this hole.
It is supplied into the case 5a from 5c. As the protective gas, for example, an inert gas or compressed air is considered.

The protective gas filled in the case 5a flows into the space 1a of the fixed base 1 through the hole corresponding to the ventilation hole 70 of the flange 5b as described with reference to FIG.
Inside the space 2b. Further, the protective gas in the space 2b flows into the case 6a of the motor unit 6 through a hole corresponding to the vent 69 shown in FIG. It is supplied into the upper space 2e. In this way, the protective gas filled in the upper space 2e passes through the hollow portion 3a of the shaft 3b of the support 3 and the space 3d of the support 3
And flows into the case 7a of the motor unit 7 through the vent hole 69. The protective gas filled in the case 7a is supplied to the space 4c in the arm 4 through the ventilation hole 70, the upper space 3e of the column 3, and the hollow 4b of the arm 4.
Subsequently, the protective gas is supplied to the motor unit 8 as shown in FIG.
In case 8a.

When the protective gas is an inert gas, the stopper of case 8a is initially
8c is removed from the hole 8b, and after evacuation of the residual air is completed after a certain time from the start of supply of the protective gas, the hole 8b is closed. When the protective gas is continuously supplied as described above, the fixed base 1, the horizontal turning part 2, the support 3, and the respective spaces 1a, 2d, 2 of the arm 4 are formed.
e, 3d, 3e, 4c and each motor unit 5-8 case 5a-8a
The pressure inside rises. When the pressure of the protective gas reaches a predetermined pressure (atmospheric pressure or higher), the supply of the protective gas is stopped. As described above, since the protective gas is supplied through the space portions 1a, 2d, 2e, 3d, 3e, and 4c having a larger flow path area than the tube or the like, the protective gas reaches the predetermined pressure in a relatively short time. Therefore, the supply or replacement of the protective gas can be performed more efficiently than before.

Further, for example, in the unlikely event that the cable 10 ₁ to 10 ₆ by breakage of the oil seal is leaked from the protective gas part of a portion which is mounted is connected to a conventional manner a gas supply hole 5c tube (Not shown) or the above space parts 1a, 2
A pressure switch (not shown) for detecting a pressure drop is provided in b, 2c, 3d, 3e, 4c and the like, and the pressure switch detects the leakage of the protective gas and turns off the power switch. Therefore, the worker who knows that the protection gas has leaked checks each part of the electric robot and repairs the leaked portion.
Thereby, the safety of the electric robot in a flammable atmosphere is ensured.

In the above embodiment, the gas supply hole 5c of the motor unit 5 is used.
Although the protective gas is supplied more, the present invention is not limited to this, and it goes without saying that the protective gas may be supplied through the hole 8b provided in the motor unit 8.

In the above embodiment, the painting robot has been described as an example. However, the present invention is not limited to the above. For example, a clean robot used in a clean room that dislikes even a small amount of dust, such as a room where precision machines are arranged. Also applicable to When the present invention is applied to this clean robot, an internal pressure structure is used in which the gas pressure in the space such as the movable part of the clean robot and the motor case is maintained at or below the atmospheric pressure by a vacuum pump. That is, in the clean room, it is necessary to prevent dust generated inside the clean robot from being discharged into the clean room. The above object is achieved by using the configuration of the present invention and keeping each space of the robot below the atmospheric pressure to prevent dust in the robot from being diffused into the clean room even if the robot is partially damaged. be able to.

Effect of the Invention As described above, according to the present invention, since the connector and the ventilation hole are provided on the flange that seals the motor case, when the motor is mounted, the motor case with the built-in motor may be mounted. Therefore, the attachment and detachment work is easy, and the assembling process and maintenance can be performed efficiently.

Moreover, unlike the conventional case, the cable and the tube do not protrude to the outside of the robot in a slack state, and an accident such as the cable being caught by a peripheral device or a protruding object when the movable part operates can be eliminated. Safety can be ensured and reliability can be further improved. Further, instead of connecting a plurality of cables one by one as in the related art, a plurality of cables can be collectively wired using a connector or the like, so that the cable wiring work is easy and the workability is improved. It is also possible to prevent the occurrence of an accident caused by a connection error or the like. In addition, since a plurality of cables can be collectively wired, the motor unit can be easily mounted, and the cables can be easily handled during maintenance and inspection of the motor, so that maintenance can be improved. Also, since each motor is not housed in the arm, the moment of inertia of the arm is small, the operation accuracy is improved, and the supply of the protective gas can be performed using each space instead of the tube through which the cable is inserted. Therefore, it is possible to replace the protective gas in a short time, and it can also be applied to a clean robot used in a clean room. In this case, the space in each part of the robot and the inside of the motor case are kept at a predetermined pressure lower than the atmospheric pressure. By maintaining the pressure, dust generated in the robot can be effectively prevented from being discharged into the clean room.

[Brief description of the drawings]

FIG. 1 is a perspective view of an embodiment of the electric robot according to the present invention, FIG. 2 is a longitudinal sectional view of the electric robot, FIG. 3 is a transverse sectional view of a motor unit provided at a rear portion of the arm, and FIG. FIG. 5 is an enlarged longitudinal sectional view showing the inside of the motor unit, and FIG. 5 is a front view for explaining a flange of the motor case. DESCRIPTION OF SYMBOLS 1 ... Fixed base, 1a, 2d, 3d, 4c ... Space part, 2 ... Horizontal turning part, 2e, 3e ... Upper space, 3 ... Support, 4 ... Arm, 5, 6, 7, 8 …… Motor unit, 9 …… Wrist mechanism, 1
0,10 ₁ to 10 ₆ …… Cable, 13,16,22,27,34,43,43 ′ ……
Connector, 14,23,35,44,45,46 ... Motor.

Claims (1)

(57) [Claims] 1. An electric robot, wherein a movable portion is rotatably supported on a fixed base, and the movable portion is driven by a motor housed in a motor case. A closed space is formed inside each of the cases, the motor case is sealed by a flange coupled to the fixed base and the movable portion, and the flange has a connector connected to the motor, and an internal A cable connected to the connector is mounted in a space of the fixed base and the movable part, and the motor is provided in a space of the fixed base and the movable part. An electric robot, wherein gas is supplied from a space of a case and a ventilation hole of the flange, and the inside of each space is maintained at a predetermined pressure.