DE102011000097B4 - Arm coupling device for robots - Google Patents

Abstract

Arm coupling device (9) for robot (1) which connects two arms rotatably, comprising: a driving source (12) arranged in one arm of the two arms, which generates a driving force for rotating the other arm of the two arms,a Rotary joint (37) composed of a body (17) having a cylindrical shape and fixed to a frame of one arm, and a shaft (15) rotatably inserted in a central part of the body (17). , a bearing (16) which is provided on the side of one arm and rotatably supports the end of the shaft (15), the body (17) of the rotary joint (37) having a cylindrical shape and having a flange part (19) at a end at which it is fixed to the frame of one arm, the body (17) being attached to the frame of one arm via a collar screw (54) which can be screwed into a hole (51) made in the flange part (19). is formed, is inserted, is fastened,wherein an elastic Ba u part (53) is interposed between a part of a stem part (54b) of the collar screw (54) and an inner wall of the hole (51), and the elastic member (53) contacts the inner wall with a first gap between a part different from the part of the trunk part (54b) and the inner wall of the hole (51), and wherein a second gap smaller than the first gap is provided between the part of the trunk part (54b) and the elastic member (53).

Description

BACKGROUND OF THE INVENTION

Technical field of the invention

This invention relates to an arm coupling device for robots, which has an arm connected at an origin where a driving source is arranged and another arm connected at an end connected by the Power source is rotated, connects.

DESCRIPTION OF THE RELATED ART

An arm coupling device which connects an initial arm on which a driving source (a motor and reduction gear) is arranged and an ending arm rotated by the driving source is provided for, for example, a connecting portion of an industrial robot ( for example be on the JP 2002 - 239 967 A referenced).

A shaft (crankshaft) having a crank part is used for the arm coupling device disclosed in US Pat JP 2002 - 239 967 A is used to transmit the driving force from the driving source to the end arm.

A hollow part such as a pipe is provided in such a way that in this case it penetrates through an inner part of the above-mentioned crank part, and thus a structure which is piping for supplying compressed air etc. and wiring for transmitting electrical signals into the pipe.

According to the above-mentioned structure, the piping and the wiring are drawn out from a different position from the driving source (a position on the arm near a base rather than on the initial arm).

For this reason, a space extending in an axial direction is required in the vicinity of a rotating center of the crankshaft only for passage of piping and wiring.

Furthermore, in a case where the arm rotates, a space for allowing movements of the piping and wiring (a movement space) is also required.

In particular, since the wiring is twisted lengthwise with the rotation, it is necessary to secure the space for the movement.

Usually, there are at least ten or more wires in the robot, which must be routed from the base side to a hand side.

From such a situation, as the number of wirings increases, it is necessary to provide a large space extending in the above-mentioned axial direction, while a length of the crankshaft in an axial direction has to be lengthened in connection therewith, whereby the arm gets longer.

Now, it is desirable that the robot has a size as small as possible in order to suppress the possibility of the robot colliding with surrounding equipments.

It is also desirable for the robot to have its joint movable range wider to realize the diversification of operations so that the robot can respond to various operations that a user demands.

From the above, the robot is required to be downsized or miniaturized, as well as the expanded range of movement of the joint.

In order to meet such a requirement, there has been a limitation with the structure mentioned above.

Then, in order to respond to the above-mentioned requirements, it is possible to employ a cavity-like rotating shaft as an axis that transmits the driving force (for example, refer to International Publication No. WO 2004/078423 A1).

When the cavity-like rotating shaft shown in International Publication No. WO 2004/078423 A1 is employed, the length of an arm can be shortened compared with a case where the crankshaft is employed.

However, the tubing and wiring runs down the center of the cavity-like rotating shaft.

For this reason, it becomes difficult to expand the range of motion of the joint due to limitation of rotation which caused by twisting of the piping and wiring.

That is, when the cavity-like rotating shaft is employed, the requirement for miniaturization can be achieved, but the requirement for diversification of operations cannot be achieved.

the JP 2004 - 90 135A discloses the following: A range for rotating a second arm to a first arm is to be sufficiently expanded even with a comparatively simple structure. A second arm frame is connected to the tip of a third arm frame to rotate on a shaft, and the arm is driven to rotate by a servo motor, a reduction gear, an output shaft and a connecting plate. An air tube passed through a connecting part is formed of a flexible tube and spirally and gently wound around the inner peripheral side of the tip of an output shaft. A wire formed of a plurality of wires, which is passed through the connecting part, is formed of a flexible flat cable and gently wound around the outer peripheral side of the tip of the output shaft. A cylindrical partition plate dividing into the inner and outer peripheral sides between a winding part of the flexible tube and a winding part of the flat cable is provided, and a cylindrical cover is provided on the outer peripheral side of the winding part of the flat cable.

JP H05-293788 A discloses the following: In order to prevent the occurrence of slack, pull up and slack an air hose, a control signal line and a current collecting cable for welding, which are positioned near the wrist of a robot. STRUCTURE: A rotary joint mechanism is provided to include a rotary joint body which follows a movement of an output driving part for a wrist and is provided at a tip part with a mounting bracket for a cylinder, and a rotary joint body which surrounds part of the outer periphery of the rotary joint body and is integral attached to an exit fitting for a wrist. The connection fixing body is provided with an air inlet port for introducing working air, a signal wire insertion port 14 through which electric wiring for transmitting a control signal is inserted, and a cable mounting part to which a power collecting cable for welding. Even if a wrist is rotated widely, an air hose protruding from the joint rotating body is prevented from occurring with a peripheral device and contact thereof with each other, and absorption of welding heat and welding spatter is minimized as much as possible.

the DE 199 56 176 A1 relates to a gripping or actuating arm with at least two links, each of which can be moved, in particular rotated and/or pivoted, relative to one another and/or to a base by means of an electric motor drive, the drives for carrying out defined movements of the links being controllable separately and wherein furthermore, a sensor arrangement is provided in each case for determining the relative position of two adjacent members. According to the invention, the drives are designed as drive units, each of which has at least one electric motor, the motor control necessary for actuating the electric motor, optionally a gear and the sensor arrangement. Furthermore, the drives of all the elements are connected in series in the manner of a bus arrangement in such a way that the energy required to actuate the drives and the control signals can be transmitted via the bus arrangement.

the DE 34 10 637 A1 discloses an electrical cable routing in the swivel joint of an industrial robot. The electrical ribbon cable in the rotary joint of an industrial robot is wound around the rotary shaft in the form of a spiral, so that movement angles > 360° can also be carried out.

SUMMARY OF THE INVENTION

The present invention was made to solve the above-described problem and has an object to provide an arm-coupling device for robots, which reduces the size thereof as well as expands the range of motion of a link.

This object is solved by the subject matter of claim 1.

In an arm-coupling device for robots according to a first aspect, the arm-coupling device for robots has a driving source arranged in one arm (hereinafter called “initial arm”) of the two arms, which generates a driving force for rotating another arm ( hereinafter referred to as “end arm”) producing two arms, a rotary joint composed of a body having a cylindrical shape and fixed to a frame of the start arm, a shaft rotatable in a middle part (an inner space of the cylinder) of the body, a bearing which is provided on the beginning arm side and rotatably supports the end of the shaft, and a cylindrical housing arranged to enclose at least part of a peripheral portion of a body of the rotary joint.

The rotary joint transmits the driving force of the driving source to the end arm via the shaft while releasing a gas (compressed air, for example) flowing to the end arm side from the leading arm side through a gas passage which or which is provided between the body and the shaft.

With such an arrangement or construction, compressed air etc. can be supplied to the end arm from the start arm without using conventional piping technology.

Accordingly, it becomes unnecessary to secure a space for allowing movements of the piping (a movement space) as in the conventional technology, whereby downsizing of the apparatus can be achieved.

A rotary flat cable unit is provided, which transmits the electric signal (e.g., a control signal and an electric power supply signal) supplied to the end arm side from the start arm side through the flat cable.

A belt-like flat cable longer than a circumference of the case is accommodated in the case where the flat cable is wound at least once in conformity with an inner circumference of the case.

That is, the space for accommodating the flat cable is arranged in a position overlapping in the axial direction of the rotary joint.

Usually, such a flat cable is very compact in comparison with wiring for transmitting signals of the same number.

Furthermore, a space for enabling operation of the flat cable (moving space) at the time of rotating the arm turns into a space on the circumference side of the rotary joint body.

That is, the movement space for the flat cable is also arranged in the position overlapping in the axial direction of the rotary joint.

Accordingly, it becomes unnecessary to secure a larger space for accommodating the wiring which transmits an electric signal and the movements of operation in the axial direction as in the conventional technology, whereby the miniaturization of the device can be achieved. In particular, the length in the axial direction can be shortened.

According to the above-mentioned structure, a wide range of angles in which the arm can rotate can be achieved as compared with a structure of conventional technology.

That is, the angular range in which the end arm can rotate is determined depending on the length of the flat cable.

For this reason, the range of movement of the connection can be expanded as the flat cable becomes longer.

According to the above-mentioned structure, only the number of turns of the flat cable at the time of accommodating the flat cable in the inner periphery of the housing increases even if the flat cable becomes longer.

As a flat cable which is accommodated in accordance with the inner periphery of the housing in this way, for example, a flexible printed circuit board (FPC=Flexible Printed Circuit) or a flexible flat cable (FFC=Flexible Flat Cable) is used because the length in the thickness direction is usually short compared to an ordinal cable (very thin compared to the ordinal cable).

For this reason, only additional accommodation space and operating space are necessary for the increased thickness of the flat cable, and it is not necessary to greatly increase these spaces even if the number of turns of the flat cable increases.

Accordingly, there will be no problem for downsizing of the arm even if the flat cable is lengthened to expand the range of movement of the connection.

Thus, according to this arrangement, downsizing of the robot is realized while expansion of the moving range of the linkage becomes possible.

In the device according to the first aspect, the shaft of the rotary joint is in a state of being supported only by the bearing provided in the initial arm (so-called cantilever state).

A large load is applied to the shaft of the cantilever state mentioned above when the robot is operated with the highest load.

The distance between the shaft and the body (an inner diameter of the body and an outer diameter of the shaft) is designed such that airtightness can be ensured after considering a gap of the shaft by the load applied to the shaft at the time of operation applied with the highest load.

However, if the shaft displaces greatly more than expected due to, for example, deterioration of the bearing due to aging etc., a situation will arise in which the gas passing through the gas passages leaks outside (gas leakage).

Although such a problem is solvable by employing the structure that provides the bearing in both sides of the shaft of the slewing ring (at the beginning arm side and the end arm side), employing this structure with the purpose of realizing do not correspond to a reduction in the size of the robot.

In the arm-coupling device for robots according to a second aspect, the body of the rotary joint has a cylindrical shape and is provided with a flange part in one end at which it is fixed to the frame of the initial arm, the body being fixed to the frame of the initial arm is fixed via a collar bolt inserted into a hole formed in the flange portion, an elastic member being interposed between a part of a trunk portion of the collar bolt and an inner wall of the hole, and the elastic member having the inner wall, wherein a first gap is provided between a portion other than the portion of the stem portion and the inner wall of the hole, and wherein a second gap smaller than the first gap is provided between the portion of the stem portion and the elastic member.

character list

• 1 eine perspektivische Ansicht eines Roboters, gezeigt in einer ersten Ausführungsform;
• 2 eine Teilschnittansicht einer Struktur bzw. eines Aufbaus eines Drehverbindungsabschnitts;
• 3 eine vergrößerte Darstellung eines Teiles der 2;
• 4 eine Schnittansicht einer Verdrahtungseinrichtung für die Drehverbindung;
• 5 eine perspektivische Ansicht eines Flachkabels;
• 6 eine Schnittansicht einer schwimmend-abstützenden Struktur;
• 7 eine Figur äquivalent zu 2, wenn eine Anordnung bzw. Ausrichtung verschoben wird, und
• 8 eine Figur äquivalent zu 6 für die zweite Ausführungsform.

In the attached drawings shows:

• 1 a perspective view of a robot shown in a first embodiment;
• 2 12 is a partial sectional view of a structure of a rotary joint portion;
• 3 an enlarged view of part of the 2 ;
• 4 a sectional view of a wiring device for the rotary joint;
• 5 a perspective view of a flat cable;
• 6 a sectional view of a floating-supporting structure;
• 7 a figure equivalent to 2 , when an arrangement or orientation is moved, and
• 8th a figure equivalent to 6 for the second embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Some embodiments of the present disclosure will be described hereinafter with reference to the accompanying drawings.

(First embodiment)

Hereinafter, the first embodiment of the present invention will be explained with reference to FIG 1 until 5 explained.

1 shows a structure of a conventional industrial robot.

A robot 1, which in 1 shown is constructed as a perpendicular-multi-joint-type robot having, for example, six axes.

The robot 1 has a base 2 , a shoulder part 3 , a lower arm 4 , a first upper arm 5 , a second upper arm 6 , a wrist 7 and a flange 8 .

The shoulder part 3 is rotatably supported by the base 2 in a horizontal direction. The lower arm 4 is rotatably supported by the shoulder part 3 in a vertical direction. The first upper arm 5 is rotatably supported by the lower arm 4 in a vertical direction. The second upper arm 6 is rotatably supported by the first upper arm 5 . The joint 7 is rotatably supported by the second upper arm 6 in a vertical direction. The flange 8 is rotatably supported by the joint 7 . An end effector (a hand) is attached to the flange 8, which is a tip of an arm.

The base 2, the shoulder part 3, the lower arm 4, the first upper arm 5, the second upper arm 6, the joint 7 and the flange 8 function as arms of the robot 1, and each arm except the base 2 is one after the another rotatably connected to the lower position arm by a pivot connection.

The rotary joint connecting these arms has a structure of providing a shaft rotatably in the former arm and connecting the latter arm to the shaft. The rotary joint is constructed in such a way that the latter arm rotates in unison with the shaft.

Each arm other than the above-mentioned base 2 has, for example, an actuator or a motor (neither of which is shown) for a drive source.

To provide power to these motors, to provide a control signal from a robot controller (not shown) to a control circuit of the motor, or to to transmit to the robot controller a rotation detection signal from a rotary encoder (not shown) provided near the motor, cables (not shown) are connected inside the robot 1 from the base 2 to the wrist 7 led to a tip.

When the final robotic actuator attached to the flange 8 is a hand, the cable is used for supplying power to the motor related to the actuator of the hand, or for transmitting and receiving a control signal A control signal and a rotation detection signal are passed between the hand motor and the robot controller inside the robot 1 .

If the end robot agent is a camera, a vision monitor unit, the cable for powering the camera or transmitting a photographic image signal from the camera is led to the robot controller inside the robot 1.

2 Fig. 12 shows mainly the structure of the rotary joint which rotatably connects the second upper arm 6, which is a latter arm, to the first upper arm 5, which is a preceding arm. 3 shows an enlarged view of a construction or a structure of the slewing ring.

In the rotary joint 9 (equivalent to the arm-coupling device for robots), a driving source 11 which generates the driving force for rotating the first upper arm 5 in the vertical direction is in a rear end part of a housing 10 which is a first upper arm frame 5 (equivalent to an arm) is arranged.

A driving source 12 which generates the driving force for rotating the second upper arm 6 (equivalent to another arm) is arranged in a central part of the housing 10. As shown in FIG.

A reduction gear 13 constituting the drive source 12 is disposed within the intermediate portion of the case 10. As shown in FIG.

A rotary shaft of the motor 14 constituting the drive source 12 is connected to a feed shaft (not shown) of the reduction gear 13. As shown in FIG. A shaft 15 is connected to an output shaft (not shown) of the reduction gear 13 .

The second upper arm 6 is connected to the shaft 15 via a connecting member 18 . The shaft 15 is rotatably supported by a bearing 16 in one end side of the reduction gear 13 . The bearing 16 is fixed to the housing 10 .

Accordingly, the shaft 15 has a function of transmitting an output torque of the reduction gear 13 to the second upper arm 6 and a function of cantilever support of the second upper arm 6.

With such a construction, when the motor 14 is operated, its rotation is decelerated by the reduction gear 13 and then transmitted to the shaft 15, and the second upper arm 6 rotates.

A sleeve 17 (equivalent to a body) is formed in an outside of the shaft 15 . The bush 17 has a cylindrical shape, and the shaft 15 is rotatably fitted (sleeved) in a cylinder (middle part) of the bush 17 . The socket 17 has a flange portion 19 in a rear end (right end in Fig 2 ).

The flange portion 19 is fixed to the bearing 16 which is fixed to the housing 10 by a floating support structure which will be mentioned later. A wiring device for rotary unions 20 is formed such that a peripheral part of the bushing 17 other than the flange part 19 is surrounded.

The wiring device for rotary joints 20 is used for wiring passing through a rotary joint portion (details will be mentioned later) among the wirings of the cables for transmitting each electric signal mentioned above and routed inside the robot.

Now, an air pressure actuator which moves the hand, for example, is arranged as the end robot actuator at the tip part of the flange 8 (not shown). Compressed air for operation (equivalent to gas) is provided to the air pressure actuator. The compressed air provided to the air pressure actuator is discharged from the air pressure actuator after operation.

In the present embodiment, an air supply passage for supplying compressed air to the air pressure actuator and an air discharge passage for routing the air discharged from the air pressure actuator to a predetermined discharge location are arranged such that the passages run along the inside of the housing of each arm.

Since the air supply passage and the air exhaust passage must absorb the rotation of the second upper arm 6 to the first upper arm 5, a part of the passages are formed using the shaft 15 and the bushing 17 of the rotary joint 9.

Namely, in the liner 17, two relay passages having positions changed in an axial direction, i.e., an air inlet side relay passage 21 and an air outlet side relay passage 22 are formed in the liner 17.

The air-inlet-side relay passage 21 and the air-outlet-side relay passage 22 are formed by penetrating the sleeve 17 in an inside-outside direction, and below end openings at both ends are the air supply passage and the air outlet passage (neither of which are shown) leading to the latter lower arm 4 lead connected to an end opening formed in an outer periphery of the bushing 17 .

Although not shown, the air supply passage and the air exhaust passage are extended to one of the arms, for example, an arm inside the base 2 via air passages formed in each arm, and led out from the base 2 to the outside.

An end part of the air supply passage is connected to an air compressor (not shown) which is a compressed air supply source, and an end part of the air discharge passage is extended to a predetermined discharge location.

Two annular grooves separated in the axial direction, i.e. an annular groove for air supply 23 and an annular groove for air outlet 24 are formed in an outer periphery of the shaft 15 such that the grooves 23 and 24 go around the outer periphery of the shaft 15.

A formation position of the air supply annular groove 23 and the air outlet annular groove 24 in the axial direction coincides with a formation position of the air inlet side relay passage 21 and the discharge side relay passage 22 of the liner 17 .

Accordingly, the air-inlet-side transfer passage 21 opens to the annular air-supply groove 23 and is maintained in a state where the annular air-supply groove 23 and the air-inlet-side transfer passage 21 are continuously connected.

In addition, the air-discharge-side transfer passage 22 opens to the annular air-outlet groove 24 and is maintained in the state where the annular air-outlet groove 24 and the air-discharge-side transfer passage 22 are continuously connected.

In the shaft 15, two relay passages, i.e., an air supply outlet side relay passage 25 and an air outlet inlet side relay passage 26 are formed in an L-shape.

End openings of the air supply outlet side relay passage 25 and the air outlet inlet side relay passage 26 open to the annular groove for air supply 23 and the annular groove for air outlet 24.

Other end openings of the air supply outlet side relay passage 25 and the air outlet inlet side relay passage 26 open to the external surface of the shaft 15, for example, an end surface of the second upper arm side.

An air supply connection pipe 29 and an air outlet connection pipe 30 are connected to the other end openings of the air supply outlet side relay passage 25 and the air outlet inlet side transfer passage 26 via pipe connections 27 and 28 connected.

The air supply connection pipe 29 and the air outlet connection pipe 30 are connected to an air supply passage and an air outlet passage (neither shown) after the second upper arm 6 .

The air supply passage and the air discharge passage after the second upper arm 6 are connected to the air inlet/outlet of the air pressure actuator.

A first O-ring groove 31, a second O-ring groove 32 and a third O-ring groove 33 are formed in the outer periphery of the shaft 15. As shown in FIG. The O-ring grooves 31, 32 and 33 are arranged on both sides of the annular groove for air supply 23 and the annular groove for air outlet 24.

The second O-ring groove 32 in the center serves as an O-ring groove of one side of the air supply annular groove 23 and the air outlet annular groove 24.

The O-rings 34, 35 and 36 are inserted into the first O-ring groove 31, the second O-ring groove 32 and the third O-ring groove 33, respectively. Between the shaft 15 and the bushing 17 is sealed with the O-rings 34, 35 and 36 and air is prevented from entering the annular groove to the air supply 23 and the annular groove to the air outlet 24 through a narrow gap between the shaft 15 and of the socket 17 enters or exits from these.

The shaft 15, the bushing 17 and the O-rings 34, 35 and 36 form a rotating connection 37 in the present embodiment.

4 shows the structure of the wiring device for slewing rings 20.

Housing a belt-like long flat cable 42 in a case 41 constitutes the wiring device for rotary joints 20 (equivalent to a rotary flat cable unit).

The housing 41 has a cylindrical shape with both ends wide open.

The housing 41 is relatively rotatably attached to the sleeve 17 so that the peripheral portion of the sleeve 17 is surrounded. A slit 41a is formed on the case 41 by drawing a circular arc from an inner periphery of the case 41 toward an outer periphery. The slit 41a opens in the outer periphery of the case 41 with a predetermined width.

An end part of the flat cable 42 housed in the case 41 is supported on the outer periphery of the socket 17 via a support member (not shown). Another end part of the flat cable 42 is inserted into the slit 41a of the case 41 .

The other end part of the flat cable 42, which is inserted into the slit 41a of the housing 41, is pressed onto an inner surface of the slit 41a by a pressing member 44 fixed to the housing 41 to form an opening of the slit 41a in the outer periphery of the Housing 41 to close.

Thus, the flat cable 42, both ends of which are attached to the housing 41 and the bushing 17, is in a state of being loosely wound around the circumference of the bushing 17 by the necessary number of times (at least once) in a spiral shape is.

In other words, the flat cable 42 is accommodated in a loosely wound manner in a spiral state in conformity with the inner periphery of the case 41 .

That is, a space for accommodating the flat cable 42 is arranged in the position overlapping the bushing 17 in the axial direction.

5 shows the structure of the flat cable.

In the present embodiment, a flexible printed circuit (FPC) is used as the flat cable 42 . A flexible flat cable (FFC=Flexible Flat Cable) can be used as the flat cable 42 .

Usually such a flat cable 42 becomes very compact compared to a cable for transmitting the signal of the same number.

The flat cable 42 has extended parts 42a and 42b at both ends, which are mutually extended in different directions at right angles. Connection terminals 45 and 46 are attached in tip parts and end parts, respectively, of the extended parts 42a and 42b. Such a configuration makes it possible for both ends of the flat cable 42 to be pulled out of the housing 41 .

As in 2 As shown, the wiring device for rotary joints 20 is arranged on the rotary joint 9 about a center of relative rotation of the housing 41 and the bushing 17 with a center of relative rotation of the second upper Arm 6 and the first upper arm 5 to match.

The housing 41 is attached to the housing 47 of the second upper arm 6 via an attachment mechanism (not shown).

Although not shown, the extended portion 42a of the flat cable 42 drawn from the case 41 is accommodated in the first upper arm 5, and the connection terminal 45 is fixed to a predetermined portion of the first upper arm 5. As shown in FIG.

The connection terminal 45 is connected to a cable wired in the first upper arm 5 via another connection terminal.

The extended part 42b of the other side of the flat cable 42 drawn out of the case 41 is accommodated in the second upper arm 6 and the connection terminal 46 is connected to a predetermined part of the second upper arm 6 .

The connection terminal 46 is connected to a cable wired in the second upper arm 6 via another connection terminal.

As described above, the cable wired in the first upper arm 5 and the cable wired in the second upper arm 6 are connected via the rotary joint wiring device 20 .

6 Figure 12 shows the floating support structure for attaching bushing 17 to bearing 16.

As in 6 1, a penetration hole 51 is formed in the flange portion 19 of the bushing 17. As shown in FIG. A protruding portion 51a is formed in a central part of an inner wall of the penetrating hole 51 . On the other hand, a screw hole 52 is formed on the bearing 16 .

An elastic member 53 side (the second upper arm 6 side or left side in 6 ), which has a cylindrical shape in which elastic deformation is possible, is in the first upper arm 5 side (right side in 6 ) of the penetration hole 51 of the part 19 where the inner wall is touched.

Another side of the elastic member 53 (the first upper arm 5 side or right side in 6 ) protrudes from the penetrating hole 51.

The flange portion 19 is inserted into the penetrating hole 51 and fixed to the bearing 16 with a collar screw 54 screwed into the screw hole 52 of the bearing 16 .

The collar screw 54 is composed of a head 54a, a cylindrical stem portion 54b and a screw portion 54c.

The head 54a of the collar bolt 54 is in contact with a surface of the protruding portion 51a of the penetration hole 51 on the second upper arm 6 side (left side in Fig 6 ).

A head 54a-side portion of the stem portion 54b of the collar bolt 54 faces an inner wall surface of the protruding portion 51a across a first gap D1.

A screw part 54c-side portion of the root part 54b of the collar screw 54 faces an inner wall surface of the elastic member 53 across a second gap D2.

A relationship between the first gap D1 and the second gap D2 is expressed by the following formula (1). $$\text{D}1>\text{<figure-callout id="2" label="D" filenames="DE102011000097B4\_0002.png" state="{{state}}">D</figure-callout>}2$$

A screw part 54C of the collar screw 54 is screwed into the screw hole 52 of the bearing 16 .

A length of the elastic member 53 in an axial direction (horizontal direction in 6 ) is chosen to an extent that when the flange part 19 is fastened to the bearing 16 by means of the collar screw 54, the first upper arm 5 side (right side in Fig 6 ) of the elastic member 53 contacts the bearing 16.

The structure, which 6 shown, a plurality of locations (e.g., three locations) of the flange portion 19 and the bearing 16 (only one location is shown in Fig 2 shown) provided.

This secures the bushing 17 to the bearing 16, i.e. the housing 10 of the first upper arm 5.

According to the structure mentioned above, the following operations and effects are obtained.

The compressed air provided by the air compressor is supplied to the air pressure actuator through the air supply passage including the air passage (equivalent to the gas passage) connected between the bushing 17 and the shaft 15 in the rotary joint 9 connecting the first upper arm 5 and connecting the second upper arm 6 is provided.

The air pressure actuator performs predetermined operations by being supplied with the compressed air.

On the other hand, the air discharged from the air pressure actuator in accordance with the operation of the air pressure actuator is discharged through the air discharge passage including the air passage (equivalent to the gas passage) formed between the sleeve 17 and the shaft 15 in the rotary joint 9 , guided to a predetermined outlet location and discharged at the outlet location.

Accordingly, the first upper arm 5 side of the air supply passage and the air outlet passage and the second upper arm 6 side of the air supply passage and the air outlet passage can be connected in a state where the rotation of the second upper arm 6 relative to the first upper arm 5 is without use conventional tubing (e.g., rubber hose, etc.) is absorbable.

For this reason, to make twists, twists or turns, durability increases while restrictions in the turning angle of the second upper arm 6 are not obtained.

Downsizing of the parts from the first upper arm 5 to the second upper arm 6 can be contributed. As a result, the robot 1 is downsized.

In the rotary joint wiring device 20, when the second upper arm 6 rotates relative to the first upper arm 5, the flat cable 42 is wound around the bushing 17 or bent between both ends to be wound, or the bending depends on the Stretched in the direction of relative rotation. As a result, relative rotation of the housing 41 and the sleeve 17, i.e. the second upper arm 6 and the first upper arm 5, is absorbed.

Thus, a space for enabling operation of the flat cable 42 at the time of rotation of the second upper arm 6 is a space on the peripheral side of the bushing 17.

Since the case 41 can be comparatively small, which can accommodate the flat cable 42 in the spiral shape, the wiring device for rotary joints 20 which performs such an operation allows wiring in a small space. Accordingly, enlargement is not required for a small robot which does not have excessive space, or only slight enlargement is required.

Since the wiring device for rotary joints 20 has the large space in the axial direction (horizontal direction in 2 ) to allow the space in which the flat cable 42 is accommodated and need not ensure its operation, the length of the first upper arm 5 can also be shortened in the axial direction.

According to the wiring device for rotary joints 20 of the present embodiment, a large angular range through which the second upper arm 6 can rotate can be obtained compared with a structure of conventional technology.

That is, the angular range through which the second upper arm 6 can rotate is determined depending on the length of the flat cable 42.

For this reason, as the flat cable 42 becomes longer, the range of movement of the connection can be expanded.

According to the structure mentioned above, only the number of windings of the flat cable 42 at the time of housing the flat cable 42 in the inner periphery of the case 41 increases even if the flat cable 42 becomes longer.

Since the thickness of the flat cable 42 is remarkably thinner compared to a conventional cable, additional accommodation space and operational space become necessary only for the increased thickness of the flat cable 42, and it is not necessary to greatly increase these spaces even if the number of turns of the flat cable 42 increases.

Accordingly, there will be no problem in downsizing the facility even if the flat cable 42 is lengthened to expand the range of movement of the joint.

Thus, according to the wiring device for rotary joints 20 of the present embodiment, downsizing of the robot 1 is realized while expansion of the movable range of the joint becomes possible.

Now, in the rotary joint 9, the shaft 15 is in the state of being supported only by the bearing 16 provided in the first upper arm 5 (so-called cantilever state).

A large load is applied to the shaft 15 of the above lever arm state when the robot 1 is operated with the highest load.

The clearance between the shaft 15 and the bushing 17 (an inner diameter of the bushing 17 and an outer diameter of the shaft 15) is formed such that the airtightness of the air passage can be ensured after a gap of the shaft 15 by the load applied the shaft 15 is applied at the time of operation with the highest load is taken into consideration.

However, if the shaft 15 shifts (tilts) much more than expected due to the reasons such as deterioration of the bearing 16 with age, etc., for example, a situation will arise where the compressed air passing through the air passage to the outside or leaks (air leak).

In the present embodiment, the floating support structure is as shown in FIG 6 shown, inserted in the portion which attaches the bushing 17 to the bearing 16 attached to the housing 10 of the first upper arm 5.

At this time, when an arrangement of the shaft 15 is shifted due to deterioration of the bearing 16 with age, etc., as shown in FIG 7 As shown, the entire assembly, which is positioned on the second upper arm 6 side, displaces from the bearing 16 only by the same amount as the shaft 15.

In 7 a double-dot chain line shows the state before the shift, and a solid line shows the state after the shift.

For this reason, when shaft 15 translates, only the same circumference moves in the same direction as bushing 17.

A range in which the bushing 17 can move through the floating support structure is the range until the stem part 54b presses the bushing 17 by elastic deformation of the elastic member 53 leading to the stem part 54b of the collar bolt 54 is pressed.

Namely, in the above-mentioned floating support structure, only the area which subtracts the second gap D2 from the first gap D1 is the area by which the bushing 17 can move.

Accordingly, even if a backlash such as shifting of the shaft 15 originating from deterioration of the bearing 16 with age, etc. occurs, if the backlash is within the range by which the bushing 17 slides the floating support structure mentioned above can move the components including the bushing 17 only by the same amount as the gap of the shaft 15.

Thereby, since the physical relationship of the sleeve 17 and the shaft 15 does not change, occurrence of the air leak in the air passage can be suppressed.

Furthermore, the second gap D2 between the root part 54b of the collar screw 54 and the inner surface of the elastic member 53 is made smaller than the first gap D1 between the root part 54b of the collar screw 54 and the inner surface of the protruding portion 51a.

For this reason, when the bushing 17 moves in accordance with the above-mentioned floating support structure, the stem portion 54b of the collar screw 54 contacts the elastic member 53 before the bushing 17 does.

Thereby, the stem portion 54b of the collar bolt 54 contacts the bushing 17 after the elastic member 53 absorbs an impact in response to the damping action of the elastic member 53.

For this reason, contact with the collar screw 54 and the bushing 17 is not strong, and it is only a weak collision, so that noise does not occur.

Accordingly, it becomes difficult for the expansion of the above-mentioned displaced arrangement to occur due to the deformation of the components by the collision.

Thus, since the floating supporting structure which makes occurrence of the backlash expansion difficult due to the movement of the bushing 17 is employed, operation and effects which the displaced arrangement of the wave 15 mentioned above can be surely obtained.

(Second embodiment)

Hereinafter, the second embodiment, which has a floating supporting structure for fixing the bushing 17 to the bearing 16 different from the first embodiment, will be referred to with reference to FIG 8th explained. In the second embodiment, the components identical to or similar to those in the first embodiment are given the same reference numerals for the sake of omission of explanation.

8th is a figure for the second embodiment equivalent to the first embodiment shown in FIG 6 is shown.

As for the floating support structure, which in 8th shown differs from the structure of the first embodiment shown in FIG 6 shown is that a collar screw 71 is used to replace collar screw 54 .

As in 8th As shown, the collar screw 71 is made up of a bolt 72 and a sleeve 73 . The bolt 72 has a head 72a and a screw portion 72b. The cuff 73 has a cylindrical shape with both ends wide open. The collar bolt 71 is constructed by inserting the bolt portion 72b of the bolt 72 into a cylinder of the collar 73.

Thus, the collar bolt 71, which has the same configuration as the collar bolt 54 in the first embodiment, is constructed by combining the bolt 72 and the collar 73. The collar 73 is equivalent to the trunk part of the collar bolt 71 in this case.

Accordingly, the same operation and effect as in the first embodiment can also be obtained by the structure of the present embodiment.

(Other embodiments)

This invention is not limited to each embodiment described above and shown in the figures, and the following modifications or extensions may be possible.

Although each of the above-mentioned embodiments has explained the structure of the rotary joint 9 rotatably connected to the first upper arm 5 with the second upper arm 6, it is possible to adopt a structure with the same rotary joint ( Arm coupling device) to use, which is rotatably connected to other arms.

Although the bushing 17 is indirectly fixed to the housing 10 of the first upper arm 5 via the bearing 16, the bushing 17 may be fixed to the housing 10 of the first upper arm 5 directly or indirectly. The bushing 17 may be a purely cylindrical structure without having the flange portion 19.

However, as it becomes impossible to support the floating support structure, which is 6 shown, in this case it is necessary to separately insert the structure that fixes the bushing 17 to the housing 10 of the first upper arm 5 directly or indirectly.

The structure of fixing the bushing 17 to the housing 10 of the first upper arm 5 directly or indirectly is not limited to the floating supporting structure shown in 6 is limited, but other floating support structures capable of absorbing the displaced placement of the shaft 15 may be employed.

Furthermore, when the shifted arrangement of the shaft 15 does not become a problem, a structure which fixes only the bushing 17 may be employed.

Claims (1)

Arm coupling device (9) for robot (1) which connects two arms rotatably, comprising: a driving source (12) arranged in one arm of the two arms, which generates a driving force for rotating the other arm of the two arms, a Rotary joint (37) composed of a body (17) having a cylindrical shape and fixed to a frame of one arm, and a shaft (15) rotatably inserted in a central part of the body (17). , a bearing (16) which is provided on the side of one arm and rotatably supports the end of the shaft (15), the body (17) of the rotary joint (37) having a cylindrical shape and having a flange part (19). one end at which it is fixed to the frame of one arm, the body (17) being attached to the frame of one arm via a collar screw (54) which can be screwed into a hole (51) made in the flange part (19 ) is formed, is inserted, is fastened, with an elasticisc hes member (53) is attached between a portion of a stem portion (54b) of the collar bolt (54) and an inner wall of the hole (51). is arranged, and the elastic member (53) contacts the inner wall, with a first gap being provided between a part other than the part of the trunk part (54b) and the inner wall of the hole (51), and with a second gap, smaller as the first gap, is provided between the part of the trunk part (54b) and the elastic member (53).

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