JP2011078227A - Power relay swivel joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power relay swivel joint for maintaining conduction without occurrence of conduction abnormality due to unstable contact between two members that relatively rotate, and for preventing interference with the other member by storing a cable, saving on the space. <P>SOLUTION: The power relay swivel joint 1 is provided with: a fixing part 10; a rotation part 11 which relatively rotates with respect to the fixing part 10; and a first cable 32a and a second cable 32b, which transmit electricity between the fixing part 10 and the rotation part 11. The first cable 32a and the second cable 32b are disposed in a shape of a swirl surrounding a center of rotational motion. When a shaft 30 normally rotates or reversely rotates, the first cable 32a and the second cable 32b are displaced in the direction where they strongly twine around the shaft 30 or in the direction where they loosely twine around the shaft 30. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a power relay rotary joint, and more particularly, to a power relay rotary joint having a structure for relaying power between a tool mounted on the tip of an industrial robot and a main body.

  An industrial robot provided with a power relay rotary joint having a structure for relaying electric power can freely rotate a tool attached to the tip of a manipulator within a predetermined range. In order to operate a tool such as a welding gun attached to the tip of the manipulator, it is necessary to supply driving power and a control signal to the tool across the rotating power relay rotary joint.

  Patent Document 1 discloses an articulated robot that attempts to realize wiring between arms by passing a wiring cable through a guide member that passes outside the joint.

  Patent Document 2 has a slip ring structure that performs electrical connection by sliding contact between a conductive fixing portion and a conductive rotating portion that rotates with the rotation of the arm during the rotation of the arm. An articulated industrial robot that attempts to achieve electrical connection without using a robot is disclosed.

JP-A 63-288692 JP 2003-117877 A

  When the cable is passed outside the joint as in Patent Document 1, the manipulator and the cable interfere with each other during the manipulator operation, so that the operation of the manipulator is restricted and the cable is easily disconnected. Furthermore, entanglement tends to occur as the number of cables increases. Furthermore, a storage space for passing the cable outside the joint is required.

  As in Patent Document 2, when the electrically conductive fixed part and the rotating part are electrically connected by sliding contact, in a harsh environment where dust or sparks are scattered, foreign matter is mixed into the contact point and an energization abnormality occurs. Cheap. Furthermore, when the conductive fixed portion and the rotating portion are brought into sliding contact, there is a possibility that the current supply becomes unstable.

  The present invention can maintain conduction between two relatively rotating members without causing energization abnormality due to unstable contacts, and further, by accommodating the cable in a space-saving manner, It is an object of the present invention to provide a power relay rotary joint that can prevent interference.

  A first power relay rotary joint according to the present invention includes a first relative rotating part, a second relative rotating part that rotates relative to the first relative rotating part, and a first relative rotating part. And a cable for transmitting electricity to and from the second relative rotating part, and the cable has a spiral part arranged in a spiral around the center of the rotational movement.

  According to the first power relay rotary joint, conduction can be maintained between the two relatively rotating parts that rotate relatively without causing an energization abnormality due to an unstable contact. Furthermore, according to the first power relay rotary joint, since the cable can be accommodated in a space-saving manner, interference between the cable and another member can be prevented. As a combination of the first relative rotation part and the second relative rotation part, a combination of a fixed part mounted on the manipulator body side and a rotation part mounted on the tool side is exemplified.

  In the second power relay rotary joint of the present invention, the cable has a substantially circular cross section in the first power relay rotary joint.

  According to the second power relay rotary joint, since the cable has a substantially circular cross section, it is not easily deformed regardless of the force applied in any direction, and there is little friction between the inner and outer cables wound in a spiral state. Therefore, the winding diameter of the spiral part of the cable can be smoothly enlarged and reduced in accordance with the rotation of the rotating part.

  The third power relay rotary joint of the present invention includes a plurality of cables in the first or second power relay rotary joint. Furthermore, the spiral portion of each cable has a first end and a second end closer to the center than the first end. The plurality of cables include a first cable and a second cable. The winding direction from the first end to the second end of the first cable is different from the winding direction from the first end to the second end of the second cable.

  According to the third power relay rotary joint, since at least two cables having different winding directions are provided, it is possible to reduce the deviation in rotational torque during forward rotation and reverse rotation. Note that the end portion of the spiral portion does not necessarily have to be the end portion of the cable, and may be one that points in the middle of the cable.

  The fourth power relay rotary joint of the present invention further includes one or more partition walls that separate the cables in layers in the third power relay rotary joint.

  According to the fourth power relay rotary joint, by separating a plurality of cables in layers, each cable wound in a spiral state can be smoothly displaced according to the rotation of the rotating portion, and a plurality of cables can be saved in a space-saving manner. Can accommodate cables.

  According to the power relay rotary joint of the present invention, conduction can be maintained between two relatively rotating members without causing abnormal conduction due to unstable contacts, and the cable can be stored in a space-saving manner. By doing so, interference with other members can be prevented.

FIG. 1 is a perspective view of the power relay swivel joint of this embodiment. FIG. 2 is a front view of the power relay swivel joint of FIG. 3A is a cross-sectional view taken along line AA of the power relay swivel joint of FIG. 2, and FIG. 3B is a cross-sectional view taken along line BB of the power relay swivel joint of FIG. 4A is a cross-sectional view taken along line AA of the power relay swivel joint of FIG. 2 rotated forward, and FIG. 4B is a cross-sectional view taken along line BB of the power relay swivel joint of FIG. 4C is a cross-sectional view taken along line AA of the power relay swivel joint of FIG. 2 rotated in the reverse direction, and FIG. 4D is a cross-sectional view taken along line BB of the power relay swivel joint of FIG. .

  FIG. 1 is a perspective view of a power relay swivel joint 1 of the present embodiment. FIG. 2 is a front view of the power relay swivel joint 1. The power relay swivel joint 1 of the present embodiment is constituted by a fixed portion 10 and a rotating portion 11 shown in FIG. In FIG. 1 and FIG. 2, the configuration of the power relay swivel joint 1 is simply illustrated for convenience of explanation. The power relay rotary joint of the present invention is not limited to the power relay swivel joint 1 of the present embodiment shown in FIGS. 1 and 2. Hereinafter, the up-down direction, the left-right direction, and the front-rear direction are used for convenience to describe the relative positional relationship.

  The fixed portion 10 has a pedestal portion 20, a foot portion 21, and a wall portion 22 integrally formed of a metal material as shown in FIG. 1, and further has a drive shaft 23 formed of a metal material shown in FIG. is doing. As shown in FIG. 1, the pedestal portion 20 has a substantially cylindrical outer shape having a central axis along the vertical direction. A donut-shaped disk-shaped upper surface 24 is formed above the pedestal 20. The foot portion 21 is integrally formed below the pedestal portion 20 and has a structure that can be attached to and detached from other members. As shown in FIG. 2, the pedestal portion 20 and the foot portion 21 have a cylindrical through hole 25 along the central axis. The drive shaft 23 is held in the through hole 25 so as to be rotatable forward and backward so as to be coaxial with the through hole 25. As shown in FIG. 1, the wall portion 22 is erected up to a predetermined height from a semicircular arc-shaped position that constitutes about half of the outer peripheral edge portion on the upper surface 24 of the pedestal portion 20.

  The rotating part 11 includes a shaft part 30 as shown in FIG. 2, seven partition walls 31, first to sixth cables 32a to 32f, six outer terminals 33, and six inner terminals 34 as shown in FIG. It is configured.

  As shown in FIG. 1, the shaft portion 30 is formed in a substantially cylindrical shape from a metal material. The shaft portion 30 has a central axis along the vertical direction, and is connected to the upper end of the drive shaft 23 of the fixed portion 10 at the lower end portion as shown in FIG. The shaft portion 30 and the drive shaft 23 are configured to be detachable. When the shaft portion 30 is connected to the drive shaft 23, the central axis of the shaft portion 30 is located on the extension of the central axis of the drive shaft 23.

  As shown in FIG. 1, each partition wall 31 is made of resin and has a donut disk shape that is slightly smaller than the upper surface 24 of the pedestal portion 20. Each partition wall 31 has a circular central hole 35 and two notches 36 formed so as to be slightly cut outward from the central hole 35. The two notches 36 are disposed opposite to each other at a position 180 ° apart on the inner periphery of the partition wall 31. Each partition wall 31 is disposed so as to surround the shaft portion 30 in a plane orthogonal to the central axis of the shaft portion 30, and is fixed to the shaft portion 30 in the vicinity of the central hole 35. The seven partition walls 31 are arranged at predetermined intervals along the direction of the central axis of the shaft portion 30. The interval between the partition walls 31 may be defined by a position fixed to the shaft portion 30, or may be maintained by inserting a spacer.

  As illustrated in FIG. 2, the first to sixth cables 32 a to 32 f are disposed between the partition walls 31 one by one in order from the lower side. The first to sixth cables 32a to 32f are configured by one or a plurality of conductive wires coated with an insulating material. The cross sections of the first to sixth cables 32a to 32f are all substantially circular. The diameters of the first to sixth cables 32 a to 32 f are slightly smaller than the interval between the partition walls 31, but are preferably larger than half the interval between the partition walls 31. This is important in that, when a cable is arranged in a space formed by two upper and lower partitions 31, the cable does not overlap in a triple layer and can maintain a spiral state in a single layer state. In addition, although the cross section of the 1st-6th cables 32a-32f is not restricted to a circle, it is preferable to have the shape which does not deform | transform easily even if it receives a pressure from which direction.

  Fig.3 (a) is AA sectional drawing of the electric power relay swivel joint 1 of FIG. One end of the first cable 32 a is attached to the rear end of the L-shaped outer terminal 33. The outer terminal 33 is fixed to the left end edge portion 40 of the wall portion 22 and is disposed so that the front end protrudes leftward from the partition wall 31.

  The other end of the first cable 32 a is attached to the rear end of the L-shaped inner terminal 34. The inner terminal 34 connected to the first cable 32a is located on the right side of the shaft portion 30 in the initial state. A branch on the rear end side of the inner terminal 34 is disposed between the partition walls 31. The other branch of the inner terminal 34 is fixed to the shaft portion 30 so as to penetrate the notches 36 of the plurality of partition walls 31 in the vertical direction. The front end of the inner terminal 34 is exposed upward from a cutout 36 on the right side of the uppermost partition wall 31 as shown in FIG.

  As shown in FIG. 3A, the first cable 32 a is wound around the shaft portion 30 from the outer terminal 33 to the inner terminal 34 in the clockwise direction. In the initial state, the first cables 32a are arranged in a spiral shape with an interval so as not to contact.

  The third cable 32c and the fifth cable 32e shown in FIG. 2 are arranged in the same manner as the first cable 32a. As with the first cable 32a, the outer terminal 33 is connected to one outer end of the third cable 32c and the fifth cable 32e, and the inner terminal 34 is connected to one inner end. The upper inner terminal 34 is configured such that the length in the vertical direction becomes shorter. As shown in FIG. 1, the three inner terminals 34 on the right side of the shaft portion 30 are arranged side by side in the rotational direction so as not to interfere with each other.

  FIG. 3B is a BB cross-sectional view of the power relay swivel joint 1 of FIG. One end of the second cable 32 b is attached to the rear end of the L-shaped outer terminal 33. The outer terminal 33 is fixed to the right edge 41 of the wall 22 and is disposed so that the front end protrudes from the partition wall 31 to the right.

  The other end of the second cable 32 b is attached to the rear end of the L-shaped inner terminal 34. The inner terminal 34 connected to the second cable 32b is located on the left side of the shaft portion 30 in the initial state. A branch on the rear end side of the inner terminal 34 is disposed between the partition walls 31. The other branch of the inner terminal 34 is fixed to the shaft portion 30 so as to penetrate the notches 36 of the plurality of partition walls 31 in the vertical direction. As shown in FIG. 1, the front end of the inner terminal 34 is exposed upward from a notch 36 on the left side of the uppermost partition wall 31.

  As shown in FIG. 3B, the second cable 32 b is wound around the shaft portion 30 counterclockwise from the outer terminal 33 to the inner terminal 34. In the initial state, the second cables 32b are arranged in a spiral shape with an interval so as not to contact.

  The fourth cable 32d and the sixth cable 32f shown in FIG. 2 are arranged in the same manner as the second cable 32b. Similarly to the first cable 32a, an outer terminal 33 is connected to each outer end of the fourth cable 32d and the sixth cable 32f, and an inner terminal 34 is connected to each inner end. The upper inner terminal 34 is configured such that the length in the vertical direction becomes shorter. As shown in FIG. 1, the three inner terminals 34 on the left side of the shaft portion 30 are arranged side by side in the rotational direction so as not to interfere with each other.

  Other cables, terminals, and other electronic components can be connected to the outer terminal 33 and the inner terminal 34. The outer terminal 33 and the inner terminal 34 are not limited to the shape of this embodiment. The outer terminal 33 may be fixed to a member other than the wall portion 22. The inner terminal 34 may be fixed to a member other than the shaft portion 30 as long as the inner terminal 34 is configured to rotate together with the shaft portion 30. The first to sixth cables 32 a to 32 f may not use the outer terminal 33 and the inner terminal 34, or the cable itself may be extended to a position away from the power relay swivel joint 1. Good.

  1 is attached to a manipulator body of an industrial robot (not shown). Between the six outer terminals 33 fixed on the left and right sides and the terminals of the manipulator body, cables for transmitting drive power and control signals are connected. A tool such as a welding gun is connected to the shaft portion 30 of the rotating portion 11. Cables that transmit drive power and control signals are connected between the six inner terminals 34 fixed to the left and right sides of the shaft portion 30 and the tool terminals. When the manipulator main body rotates the drive shaft 23 of the fixed portion 10 shown in FIG. 2, the shaft portion 30 and the tool connected to the drive shaft rotate.

  As shown in FIG. 1, in a state where the rotating part 11 is connected to the fixed part 10, the rear part of the rotating part 11 is covered with a wall part 22 and the front part is opened. When the shaft portion 30 rotates, the outer periphery of the partition wall 31 slides along the wall portion 22 of the fixed portion 10. Hereinafter, an operation in which the shaft portion 30 rotates clockwise when viewed from above is referred to as forward rotation, and an operation in which the shaft portion 30 rotates counterclockwise when viewed from above is referred to as reverse rotation. The shaft portion 30 of the present embodiment rotates 180 ° in the forward rotation direction and the reverse rotation direction, but the rotation angle may be larger or smaller.

  Fig.4 (a) is AA sectional drawing when the axial part 30 of the electric power relay swivel joint 1 of FIG. 2 rotates 180 degrees forward. FIG. 4B is a cross-sectional view taken along the line BB when the shaft portion 30 of the power relay swivel joint 1 of FIG. 2 rotates forward by 180 °. As the rotation angle increases during forward rotation, the first cable 32a gradually displaces inward so that the winding around the shaft portion 30 becomes tight as shown in FIG. 4 (a). As shown, the second cable 32b is displaced outward so that the winding around the shaft portion 30 is gradually loosened. The third cable 32c and the fifth cable 32e shown in FIG. 2 are displaced similarly to the first cable 32a, and the fourth cable 32d and the sixth cable 32f are displaced similarly to the second cable 32b. To do.

  FIG. 4C is a cross-sectional view taken along line AA when the shaft portion 30 of the power relay swivel joint 1 of FIG. FIG. 4D is a BB cross-sectional view when the shaft portion 30 of the power relay swivel joint 1 of FIG. As the rotation angle increases during reverse rotation, the first cable 32a is gradually displaced outward so that the winding around the shaft portion 30 is gradually loosened as shown in FIG. 4 (c). As shown, the second cable 32b is gradually displaced inward so that the winding around the shaft portion 30 is gradually tightened. The third cable 32c and the fifth cable 32e are displaced in the same manner as the first cable 32a, and the fourth cable 32d and the sixth cable 32f are displaced in the same manner as the second cable 32b.

  Since the first to sixth cables 32a to 32f of the present embodiment have a substantially circular cross section, they are more self-supporting than other shapes such as a flat cable and can be easily maintained in shape and are not easily deformed. However, even if the rotation is repeated, the cables 30 do not overlap with each other and can maintain the spiral state in a single layer state, so that the shaft portion 30 can maintain a smooth rotation for a long period of time. In addition, since the first to sixth cables 32a to 32f have a substantially circular cross section, the friction between the cables is less than that of other shapes such as a flat cable. By smoothly expanding and reducing the winding diameter of the spiral portion, the rotation operation of the shaft portion 30 can be realized smoothly. In addition, since the first to sixth cables 32a to 32f have a substantially circular cross section, the friction between the cable and the partition wall 31 is less, and the displacement of the winding diameter of the spiral part of the cable becomes smoother. The rotation operation of the shaft portion 30 can be performed smoothly.

  In addition, by setting the interval between the partition walls 31 to be about the diameter of each of the first to sixth cables 32a to 32f, It is possible to avoid the trouble that overlaps in the triple direction in the vertical direction in the space.

  In order to improve the service life of the first to sixth cables 32a to 32f and the partition wall 31 and reduce friction, a lubricant such as grease or wax is provided on at least one of the first to sixth cables 32a to 32f and the partition wall 31. May be applied.

  When viewed from above, the winding direction of the first cable 32a, the third cable 32c, and the fifth cable 32e is opposite to the winding direction of the second cable 32b, the fourth cable 32d, and the sixth cable 32f. Since it is a direction, the load at the time of forward rotation of the rotation part 11 can be made the same as the load at the time of reverse rotation. In order to reduce the bias of the mechanical load during forward rotation and reverse rotation, it is preferable that the winding direction of at least one of all the cables is different from the winding direction of the other cables. To equalize the mechanical load during forward rotation and reverse rotation, the number of cables whose winding direction is clockwise when viewed from above is the same as the number of cables whose winding direction is counterclockwise. It is preferable.

  Since the rotating part 11 is open to the front in a state of being attached to the fixed part 10, the first to sixth cables 32a to 32f can be exchanged from the front without removing the rotating part 11. In addition, it is preferable to attach a detachable cover to the fixed portion 10 so as to cover the front of the rotating portion 11 in order to prevent impurities such as dust from entering the rotating portion 11. Since the first to sixth cables 32a to 32f have a substantially circular cross section, they are not easily deformed as compared with other shapes such as a flat cable, and the cable can be easily replaced.

  The rotating unit 11 may be configured so that the interval between the partition walls 31 can be changed. The versatility is enhanced by changing the interval between the partition walls 31. Since the rotation part 11 has laminated | stacked the 1st-6th cables 32a-32f in the up-down direction, it can use the cable of a different shape and length simultaneously. The partition wall 31 may not be a plate shape, may be a mesh shape, may be a linear shape that spreads radially from the center, and partitions the first to sixth cables 32a to 32f. Other shapes that can be used may be used.

  Since the power relay swivel joint 1 of the present embodiment does not have unstable contact portions such as a contact combining a slip ring and a brush, it can prevent energization abnormality and transmit drive power and control signals with high efficiency. it can. Since the first to sixth cables 32a to 32f of the present embodiment are built in the power relay swivel joint 1, they are space-saving, do not interfere with the operation of the manipulator, and are not easily broken. Since the first to sixth cables 32a to 32f of the present embodiment are arranged in a spiral shape, the displacement of both ends due to the rotation operation can be absorbed without having an elastic force in the length direction. Since the first to sixth cables 32a to 32f of the present embodiment are arranged in a spiral shape, there is no abrupt bending portion, the mechanical load applied to the cable is small, and the cable is not easily broken.

  The present invention can be applied to various power relay rotary joints that transmit drive power, control signals, and other power.

DESCRIPTION OF SYMBOLS 1 Electric power relay swivel joint 10 Fixing part 11 Rotating part 20 Base part 21 Foot part 22 Wall part 23 Drive shaft 24 Upper surface 25 Through-hole 30 Shaft part 31 Bulkhead 32a-32f 1st-6th cable 33 Outer terminal 34 Inner terminal 35 Center hole 36 Notch 40 Left edge 41 Right edge

Claims (4)

A first relative rotation part;
A second relative rotating part that rotates relative to the first relative rotating part;
A cable for transmitting electricity between the first relative rotating part and the second relative rotating part,
The cable has a spiral portion disposed in a spiral around the center of the rotational movement,
Power relay rotary joint. The power relay rotary joint according to claim 1, wherein the cable has a substantially circular cross section. Comprising a plurality of said cables;
The spiral portion of each cable has a first end and a second end closer to the center than the first end,
The plurality of cables include a first cable and a second cable,
The winding direction from the first end to the second end of the first cable is different from the winding direction from the first end to the second end of the second cable. ,
The power relay rotary joint according to claim 1 or 2. And further comprising one or more partition walls separating the cables in layers.
The power relay rotary joint according to claim 3.