JPH11254377A - Robot - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve dustproofing and waterproofing at a joint part having a reduction gear and reduce the size of the joint part. SOLUTION: The second arm 16 is connected to the upper end of the first arm 13 through the second joint J2. The second joint J2 includes a reduction gear 17, and rotates the second arm 16 around an axis extending in the horizontal direction with drive of a second shaft motor 18. The reduction gear 17 is basically constituted of a hollow harmonic drive having a web generator 32, a flex spline 34, and a circular spline 40 around a hollow shaft 28. The wiring 43 is passed through the inside of the hollow shaft 28, and an oil seal 44 is provided on a bearing 33 fitted the outmost periphery part of the reduction gear 17.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a robot for transmitting a driving force of a motor to an arm via a speed reducer provided at a joint.

[0002]

In some robots, for example, articulated industrial robots, the driving force of a servomotor is transmitted to an arm via a speed reducer provided at a joint. FIG. 10 shows a configuration of a joint between the first arm 1 and the second arm 2 of this type of articulated robot. Here, a servomotor 3 is disposed at an upper end portion in the first arm 1, and a lower end portion of the second arm 2 is horizontally interposed via a speed reducer 4 on an upper right wall in the drawing of the first arm 1. It is connected so as to be able to rotate (turn) about an axis.

The speed reducer 4 is composed of, for example, a well-known harmonic drive (trade name). The wave generator 5 is connected to a rotating shaft 3a of the servo motor 3, and a flex spline 6 (only a tip portion is shown) ) And a circular spline 7 attached to the frame 1a of the first arm 1 at the outer periphery thereof. Further, a tip end of the flexspline 6 is connected to an output rotation unit 8, and the output rotation unit 8 is
The arm 2 is connected to the frame 2a. At this time, although not shown, a bearing is provided between the outer periphery of the output rotation unit 8 and the frame 1a of the first arm 1.

A wire 9 (indicated by a two-dot chain line) from the first arm 1 to the second arm 2 is routed on the outer peripheral side (lower part in the figure) of the speed reducer 4. I have.
Further, a sliding portion on the outer peripheral side of the speed reducer 4 between the frame 1a of the first arm 1 and the frame 2a of the second arm 2 includes:
Except for a substantially ring-shaped portion through which the wiring 9 passes, the sealing material 1
0 is provided.

On the other hand, a pair of a nipple 102 for supplying grease to the speed reducer 101 in the first arm 1 and a drain 103 for discharging old grease are provided. It is covered with a cover 104 during normal use. Also, the cover 10
A rubber packing 105 formed in a cylindrical shape is provided between the first arm 4 and the first arm 1 to ensure waterproofness.

By the way, in this type of robot,
As the size of the device increases, the size of the rubber packing also increases, making assembly work difficult. That is, the deformation of the shape of the elastic rubber packing increases with the size of the packing, and it is difficult to shape and assemble the deformed rubber packing.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a robot in which packing can be easily assembled.

[0008]

According to a first aspect of the present invention, there is provided a robot according to the first aspect, wherein a cover for closing an opening of an outer wall of the arm is attached via a waterproof packing. Instead of the conventional whole rubber packing, a metal frame portion and a rubber seal portion fixed to a side portion of the frame portion and having a thickness larger than the thickness of the frame portion. It has features.

According to this, since the shape of the packing is maintained by the metal frame portion, the mounting operation of the packing is facilitated, and the amount of tightening and, consequently, the amount of compression of the seal portion can be kept constant by the frame portion. It is possible to prevent excessive tightening and insufficient tightening.

At this time, in the packing, a side portion of the seal portion may be formed into a curved surface concave at an intermediate portion in a thickness direction (the invention of claim 2). Thereby, the stress when the seal portion of the packing is compressed in the thickness direction is absorbed by the concave portion, and the crack of the seal portion can be prevented.

By the way, during maintenance, for example, it is necessary to refuel the sliding parts of the speed reducer. This refueling was generally performed by removing a cover closing the maintenance opening. On the other hand, if the oil supply port for supplying oil to the sliding portion of the speed reducer is provided on the outer wall of the arm (the invention of claim 3), it is not necessary to remove the cover for oil supply. In addition, the refueling operation is facilitated, and refueling can be performed while preventing dust and water from entering the inside of the robot body even in a bad environment.

Further, at this time, the speed reducer provided at the joint portion for transmitting the driving force of the motor to the arm is formed in a hollow shape so that the wiring is passed through the inside thereof, and the bearing provided in the speed reducer is provided. An oil seal may be provided on the fin (claim 4).

According to this, the intrusion of dust, water, etc. into the inside can be prevented by the oil seal provided in the speed reducer, and as a result, the dust and water resistance at the joint can be improved. At this time, since the portion through which the wiring passes is on the inner peripheral side of the oil seal, the portion through which the wiring passes does not adversely affect the dustproof and waterproof properties. In addition, since the wiring passes through the inside of the reduction gear, the diameter of the joint can be reduced. Further, the operation of the arm is not restricted by the wiring, and the operation range of the arm can be expanded.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention is described as an articulated type (6 axes).
FIGS. 1 to 9 show an embodiment applied to a robot.
This will be described with reference to FIG. 2 to 4 show the external configuration of the main body 11 of the robot according to the present embodiment. The robot body 11 has a six-axis arm on a base 12 in this case, and a tool such as a hand (not shown) is attached to a tip of the arm.

Specifically, on the base 12, a first
A first arm 13 extending upward is connected via a joint J1. The first joint J1 is provided with a speed reducer 14 as shown in FIGS.
First axis motor 15 composed of C servo motor (see FIG. 5)
Is driven to rotate the first arm 13 coaxially about a vertical axis.

An upper end of the first arm 13 is connected to a lower end of a second arm 16 extending upward through a second joint J2. The second joint J2 includes a speed reducer 17 as shown in FIGS. 1 and 5, and is driven by a second shaft motor 18 (see FIG. 1) provided in the first arm 13. Is turned around an axis extending in the horizontal direction (the left-right direction in FIG. 3).

A lower end of a third arm 19 is connected to a distal end of the second arm 16 via a third joint J3. Although not shown, similarly, the third joint J3 includes a speed reducer, and the third arm 19 is driven by a third axis motor.
Is turned around an axis extending in the horizontal direction (the left-right direction in FIG. 3).

A proximal end of a fourth arm 21 is coaxially rotatably connected to a distal end (the left side in FIG. 2) of the third arm 19 via a fourth joint J4. The fourth arm 21 extends to the left in FIG.
The fifth arm 22 is pivotally connected via the joint J5. A sixth arm 23 is coaxially rotatably connected to the fifth arm 22 via a sixth joint J6. A tool such as a hand is detachably connected to the tip of the sixth arm 23. At this time, although the inside is not shown, the fourth to sixth joints J4 to J6 are provided with similar speed reducers, and reduce the driving force of the motor to transmit to the fourth to sixth arms 21 to 23. It has become.

The first to fourth arms 13, 1
Openings for maintenance are formed in the frames constituting the outer wall portions 6, 19, and 21. These openings are closed and opened by a cover via a waterproof packing, as will be described in detail later. It has become so. Specifically, a cover 24 is provided on the back surface (left side in FIGS. 1 and 3) of the first arm 13, and a cover 25 is provided on the front surface (right side in FIGS. 1 and 3) of the second arm 16. A cover 26 is provided on the back (left side in FIG. 3) of the third arm 19, and covers 27, 27 are provided on both front and rear sides (left and right sides in FIG. 3) of the fourth arm 21. It has become.

The construction of the speed reducers 14 and 17 provided in the joints J1 to J6 will be described below. In this case, since the speed reducers provided at the joints J1 to J6 have substantially the same configuration, the second joint connecting the first arm 13 and the second arm 16 is mainly described with reference to FIG. The description will be made with the reduction gear 17 of J2 as a representative.

The speed reducer 17 is arranged in a circular mounting opening formed at the upper end of the right wall portion in FIG. 1 of the frame 13a of the first arm 13, and has a hollow shape. It is constructed based on the harmonic drive (product name). The speed reducer 17 has a cylindrical hollow shaft 28 provided at the center so as to penetrate the mounting opening in the left-right direction in FIG. The right end of the hollow shaft 28 in FIG. 1 is connected to the frame 16 a of the second arm 16.

A pulley 29 is rotatably provided around the left end of the hollow shaft 28 in FIG. 1 with respect to the hollow shaft 28. A pulley 30 is attached to a rotating shaft of a second shaft motor 18 provided in the first arm 13, and a timing belt 31 is stretched between the pulley 30 and the pulley 30. Thus, the rotational driving force of the second shaft motor 18 is transmitted to the pulley 29. The right side of the pulley 29 in FIG. 1 is connected to a substantially cylindrical wave generator 32 which is disposed around the hollow shaft 28 with a slight gap.

On the other hand, the frame 13 of the first arm 13
A bearing 33 made of, for example, a cross roller bearing is disposed at the outermost periphery in the assembling opening a, and the outer ring 33a, the cup-shaped flex spline 34, and the support member 35 are superimposed in close contact with each other. Frame 13
a is fixed in a jointed state with respect to a. The wave generator 32 is rotatably supported via a ball bearing 36 provided on an inner peripheral portion of the support member 35. A ball bearing 37 is interposed between the wave generator 32 and the flex spline 34. An oil seal 38 is provided between the outer peripheral portion of the wave generator 32 and the inner peripheral portion of the support member 35 on the left side of the ball bearing 36 in FIG.

On the other hand, the frame 16a of the second arm 16 has a ring-shaped closing member 39, a circular spline 40, and an inner ring 33 of the bearing 33.
The three members b and b are placed in close contact with each other, and are fixed in the jointed state. At this time, the teeth on the inner circumference of the circular spline 40 mesh with the teeth on the outer circumference of the flexspline 34. The ball bearing 4 is also provided between the inner peripheral portion of the closing member 39 and the wave generator 32.
1 and an oil seal 42 is provided.

As a result, the rotational driving force (high speed) of the second shaft motor 18 is transmitted through the pulley 29 to the wave generator 3.
2 and decelerated by the action of the wave generator 32, the flex spline 34, and the circular spline 40 and transmitted to the circular spline 40 (slow rotation).
The second arm 16 connected to the circular spline 40 rotates with respect to the first arm 13.

At this time, as shown in FIG. 1, the inside of the hollow shaft 28 is
The wiring 43 (shown by imaginary lines) is passed inward. An oil seal 44 is provided on a side of the bearing 33 facing the gap between the first arm 13 and the second arm 16 (the right side in FIG. 1). The oil seal 44 allows dust, water, and the like from the outside of the robot body 11 to pass through the bearing 33 and reduce the speed of the reduction gear 17.
It is prevented from entering the inside and thus into the first arm 13. Further, the oil seal 44 and the oil seals 38 and 42 prevent grease (lubricating oil) injected into a sliding portion in the speed reducer 17 from leaking out of the speed reducer 17.

By the way, for example, during maintenance, it is necessary to supply grease to the sliding parts of the reduction gears 14, 17, 2 of the joints J1 to J6. In the present embodiment, a frame constituting the outer wall of each of the arms 13, 16, 19, 21, 22, 23 is provided with a fuel supply port for refueling the frame as follows. In this case, the filler port includes a pair of a nipple for supplying new grease and a drain for discharging old grease.

That is, as shown in FIG. 2 (and FIG. 6), a nipple 45 and a drain 4 for the first joint J1 (reduction gear 14) are provided on the right front of the frame 13a of the first arm 13.
6 are provided side by side. 2 and 3
And the frame 16 of the second arm 16 as shown in FIG.
The nipple 47 and the drain 48 for the second joint J2 (reduction gear 17) are respectively provided at the lower portions of the right and left sides of the “a”.
Is provided. Also, the frame 1 of the second arm 16
6a, on the right and left side portions, a third
A nipple 49 and a drain 50 for the joint J3 are provided.

Further, as shown in FIGS. 2 and 4, the third arm 19 is provided with a nipple 51 for the fourth joint J4 located at the left part of the front surface and at the left part of the upper surface. A drain 52 for the fourth joint J4 is provided at a position. The fourth arm 21 is provided with a nipple 53 for the fifth joint J5 located on the upper left side and a drain 54 for the fifth joint J5 located on the lower left side. The fifth arm 22 has a sixth arm located on the upper left side.
A nipple 55 for the joint J6 is provided, and a drain 56 for the sixth joint J6 is provided at the left side of the bottom surface.

FIGS. 5 and 6 show a part of a structure for supplying grease. As shown in FIG. 5, an oil supply passage 16b is formed in the frame 16a (right side) of the second arm 16 so as to communicate with the nipple 47 for J2, and an oil supply pipe 57 is provided at the end of the oil supply passage 16b. It is connected. The end of the oil supply pipe 57 is connected to the closing member 3.
9 is connected to an oil supply hole 39a. Thus, the grease supplied from the nipple 47 is supplied to the oil supply passage 1
6b and the oil supply pipe 57 in order, and are injected into the inside of the reduction gear 17 from the oil supply hole 39a of the closing member 39.

Similarly, an oil drain hole 39b is provided in the closing member 39, and grease in the speed reducer 17 drains through an oil drain pipe 58 and an oil drain passage 16c connected to the oil drain hole 39b. 48.
Also, as for the supply and discharge of grease to the first joint J1 (reduction gear 14), as shown in FIGS.
An oil supply pipe 59 connected to the one nipple 45 and an oil drain pipe 60 connected to the drain 46 substantially perform the same operation. Although detailed description is omitted, refueling and draining are performed with substantially the same configuration for the other joints J3 to J6.

Further, as described above, the covers 24, 25, 26, and 27 for closing the openings of the first to fourth arms 13, 16, 19, and 21 are respectively provided with waterproof packings. In this embodiment, the packing is modified as follows. In this case as well, since the configuration of the mounting portion of each of the covers 24 to 27 is substantially the same, the cover 27 on the front surface of the fourth arm 21 will be described with reference to FIGS. It shall be.

First, as shown in FIG.
Bolt holes 21b are formed at a plurality of locations at intervals on an end surface of the frame 21a around the opening. A flange 27a, which is addressed to the end surface of the frame 21a via a packing 61, is formed on the entire periphery of the cover 27, and the flange 27a is formed in a manner corresponding to the bolt hole 21b. A bolt insertion hole 27b is formed. The cover 27 is
The first arm 21 is attached to the fourth arm 21 by tightening the bolt 62 through the bolt insertion hole 27b with respect to the bolt hole 21b in a state where 1 is sandwiched.

FIGS. 7 and 8 show the structure of the packing 61. FIG. This packing 61
A rubber seal portion 64 is fixed to the entire outer periphery of a sheet metal frame portion 63 having a shape conforming to the outer shape of the end face portion a by, for example, bonding or the like. At this time, a bolt insertion hole 63a is formed in the inner peripheral portion of the frame portion 63 so as to correspond to the bolt insertion hole 27b and the bolt hole 21b. As shown in FIGS. 8 and 9, the seal portion 64 is formed to be thicker than the thickness of the frame portion 63, and has a side portion (outer surface portion) extending in the thickness direction (see FIG. (Left-right direction) A concave groove 63a having an arc-shaped cross section is formed at an intermediate portion.

As shown in FIG. 9, the packing 61 constructed as described above is provided with a bolt insertion hole 63a of the frame portion 63.
When the bolt 62 is passed through and the bolt 62 is tightened in this state, the rubber seal portion 64 is sandwiched between the flange portion 27a and the end face of the frame 21a and is compressed and deformed. Between the seals. At this time, the tightening amount of the bolt 62 is regulated by the metal frame 63, and the stress when the seal 64 is compressed in the thickness direction is absorbed by the concave groove 64a. It has become.

In the above configuration, the reduction gear 17 and the like are formed in a hollow shape and the wiring 43 is passed through the inside thereof, so that the oil seal 44 is provided on the bearing 33 on the outer periphery of the second joint J2 and the like. Became possible. Accordingly, even when the robot is used in a bad environment where dust and water easily enter the robot body 11 such as a machining factory, dust and water inside the speed reducer 17 and the arms 13 and 16 are removed. Can be prevented, and sufficient dustproofness and waterproofness at the joints J1 to J6 can be secured.

At this time, since the portion through which the wiring 43 passes is on the inner peripheral side of the oil seal 44, unlike the conventional portion through which the wiring 43 passes adversely affects the dustproof and waterproof properties, the joints J1 to J1 are not provided. Dust and water resistance at the J6 portion can be greatly improved. Since the wiring 43 passes through the inside of the speed reducer 17 and the like, the diameter of the joints J1 to J6 can be reduced.

Further, the operation of the second arm 16 and the like is not restricted by the wiring 43, and the operating range of the second arm 16 and the like can be expanded. By the way, taking the second arm 16 as an example, a conventional arm (see FIG. 10)
, The operation range of the second arm 2 is 85 degrees to the right (clockwise direction) and 100 degrees to the left (counterclockwise direction), with the vertical upper part having an angle of 0 degree. With the second arm 16 of the embodiment, an operation range of 90 degrees to the right and 135 degrees to the left could be obtained.

During maintenance of the robot body 11, oil is supplied to sliding parts such as the speed reducer 17. In this case, conventionally, the cover that closes the maintenance opening is removed to supply the fuel. In contrast, in the present embodiment, the covers 24 to 27
Without removing each arm, each arm 13, 16, 1
The fueling work (nipples 45, 47, 49, 51, 53, 55) provided on the outer wall portions of 9, 21, 22 makes it possible to easily perform refueling work from the outside. Also, it is possible to prevent dust and water from entering the inside of the robot body 11.

In this embodiment, each arm 13, 1
6, 19, 21 openings and covers 24, 25, 26, 2
7 are formed of a metal frame 63 and a rubber seal 64, so that the packing 61 is different from the conventional packing which is entirely made of rubber.
Since the predetermined shape of the packing 61 is held by the frame portion 63, the mounting work and the replacement work of the packing 61 become extremely easy. In addition, the frame 63 allows the amount of tightening when the bolt 62 is tightened, and thus the amount of compression of the seal 64, to be kept constant, thereby preventing over tightening or insufficient tightening. Further, the sealing portion 64
Is provided with a concave groove portion 64a, so that the stress generated when the seal portion 64 is compressed can be absorbed.
Cracks can be prevented from occurring.

As described above, according to the present embodiment, each arm 1
3, 16, 19, 21 openings and covers 24, 25, 2
Since the packings 61 interposed between the packings 61 and 27 are composed of the metal frame portion 63 and the rubber sealing portion 64, it is possible to prevent the packing 61 from being excessively tightened and to prevent the mounting of the packing 61 and the like. An excellent practical effect that the replacement work becomes easy can be obtained.

In this embodiment, each arm 13, 1
Nipple 45, 47, on the outer wall of 6,19,21,22
With the provision of 49, 51, 53, and 55, lubrication can be performed without opening the covers 24 to 27, and the merit that lubrication work is facilitated can also be obtained.

Further, in this embodiment, the speed reducers 14 and 17
And the like are formed in a hollow shape to allow the wiring 43 to pass therethrough, and the oil seal 44 is provided on the bearing 33 provided on the outer peripheral portion of the speed reducers 14 and 17, so that the joints J1 to J6 In this case, it is possible to improve the dustproof and waterproof properties of the armature, and to reduce the size of the joints J1 to J6 and extend the operating range of the arms 13, 16, 19, 21, 22, 23. You can do it.

It should be noted that the present invention is not limited to the above embodiment, and the nipples 45, 47, 49, 51, 5
3, 55 and drains 46, 48, 50, 52, 54, 5
6 may be provided as needed, and the configuration of the speed reducer may be the same as the conventional one, and may be appropriately changed and implemented without departing from the gist. is there.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention, and is a longitudinal left side view of a main part.

FIG. 2 is a front view of a robot body.

FIG. 3 is a left side view of the robot body.

FIG. 4 is a top view of the robot body.

FIG. 5 is a cross-sectional plan view of a state in which the second joint is crossed

FIG. 6 is a longitudinal rear view of a first joint part.

FIG. 7 is a front view of a packing.

FIG. 8 is a longitudinal sectional side view taken along line AA of FIG. 7;

FIG. 9 is a vertical right side view showing a tightened state of the packing.

FIG. 10 is a diagram corresponding to FIG. 1 showing a conventional example.

[Explanation of symbols]

In the drawing, 11 is a robot body, 12 is a base, 13, 1
6, 19, 21, 22, 23 are arms, 13a, 16
a and 21a are frames (outer wall portions), 14 and 17 are reduction gears, 15 and 18 are motors, 24, 25, 26 and 27 are covers, 28 is a hollow shaft, 33 is a bearing, 43 is a wiring,
44 is an oil seal, 45, 47, 49, 51, 53,
55 is a nipple (fuel filler), 61 is packing, 63 is a frame, 64 is a seal, 64a is a groove, J1 to J
Reference numeral 6 denotes a joint.

Claims (4)

[Claims] 1. A robot in which the driving force of a motor is transmitted to an arm via a speed reducer provided at a joint, wherein an opening for inspection or the like is provided on an outer wall of the arm. The opening is closed by a cover via a waterproof packing so as to be openable and closable. The packing is fixed to a metal frame portion and a side portion of the frame portion. A rubber seal portion having a thickness greater than the thickness of the portion. 2. The robot according to claim 1, wherein a side portion of the seal portion has a curved surface that is concave at an intermediate portion in a thickness direction. 3. The robot according to claim 1, wherein a lubrication port for lubricating a sliding portion of the speed reducer is provided on an outer wall of the arm. 4. The reduction gear is formed in a hollow shape so that wiring is passed through the reduction gear, and an oil seal is provided on a bearing provided in the reduction gear. The robot according to any one of the above.