JP2006231484A - Robot arm - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a robot arm, capable of improving precision in position control of an arm without enlarging the arm. <P>SOLUTION: This robot arm is provided with a first arm having a first transmission mechanism, a work means having a second transmission mechanism, and a first connection means for connecting the first and the second transmission mechanism to each other. The first connection means comprises a first power transmission member comprising a hard member, a second power transmission member, and a connection part comprising a hard member for connecting these to each other. The diameter of the first transmission mechanism is larger than the diameter of the second transmission mechanism. The length of the second power transmission member is shorter than the length of the first power transmission member. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a robot arm. More specifically, the present invention relates to an improvement in the structure of a robot arm in an articulated robot that moves a workpiece such as a semiconductor wafer or a liquid crystal transfer robot between process devices such as a cassette or a film attaching device.

  The robot arm is configured such that a first arm and a working means are connected to each other so as to be able to rotate. The robot arm is configured to transmit a rotational force of a rotational drive source to perform operations such as expansion and contraction. The robot arm is mounted on an articulated robot that moves a workpiece such as a semiconductor wafer or liquid crystal between process devices such as a cassette or a film-attaching device.

  For example, the robot arm 203 shown in FIG. 8 is a so-called belt direct drive type, and includes a first arm 205 that can rotate around a first timing pulley 207 fixed to a base 204 of the robot body, A second arm 206 rotatably connected to the tip of the first arm 205 via a second timing pulley 208, and a hand 202 attached to the hand side pulley 210 at the tip of the second arm 206. And a timing belt 211 stretched over the first timing pulley 207 and the second timing pulley 208.

The first arm 205 is provided with a drive shaft 213 that can rotate to a position that is concentric with the first timing pulley 207, and the first arm 205 is attached to the base 204 and the first timing pulley 207. It is pivotally supported. The drive shaft 213 is rotated by a motor (not shown) built in the base 204.
The second timing pulley 208 and the second arm 206 are fixed by a connecting cylinder 214. A connecting shaft 215 is housed in the connecting cylinder 214 so as to be rotatable.
The connecting shaft 215 is fixed to the first arm 205 and the third timing pulley 209.

  The first arm 205 and the second arm 206 have the same length, the first arm 205 accommodates two timing pulleys 207, 208 and one long timing belt 211, and the second arm 206 has two timings. The pulleys 209 and 210 and one long timing belt 212 are accommodated.

  In this robot arm 203, the ratio of the diameter (number of teeth) between the first pulley 207 and the second pulley 208 is 2: 1, and the ratio of the diameter (number of teeth) between the third pulley 209 and the fourth pulley 210 is 1. : 2 For this reason, the rotation angle ratio of the first pulley 207, the second pulley 208, and the fourth pulley 210 is 1: 2: 1.

The robot arm 203 rotates the first arm 205 with respect to the base 204 by driving a motor. At this time, the first belt 211 that rotates relative to the fixed first pulley 207 causes the second pulley 208 to rotate relative to the first arm 205. By the rotation of the second pulley 208 relative to the first arm 205, the second arm 206 rotates relative to the first arm 205 and the third pulley 209 rotates relative to the second arm 206.
Furthermore, when the third pulley 209 rotates with respect to the second arm 206, the fourth pulley 210 rotates with respect to the second arm 206 and the hand 202 rotates.

  Here, the first arm 205 and the second arm 206 have the same length, and the base side pulley 207 and the hand side pulley 208 (that is, the base side pulley 209 of the second arm 206) of the first arm 205 and the first arm 205. Since the rotation angle ratio between the two arms 206 and the hand side pulley 210 is 1: 2: 1, turning the first arm 205 changes the angle between the first arm 205 and the second arm 106. The hand 202 moves on a straight line connecting the center of the base side pulley 207 of the first arm 205 and the center of the hand side pulley 210 of the second arm 206 while keeping the direction constant.

  By the way, in the robot arm 203, when a semiconductor wafer or liquid crystal glass becomes large in recent years and the arm size and weight increase, the force applied to the timing belt increases and the rigidity of the timing belt is insufficient, so that the position accuracy of the work is lowered. There was a problem of doing.

Therefore, it is disclosed that a timing belt in which a connecting portion made of a metal plate is connected to an area that does not come into contact with the pulley during rotation is used instead of using a single long timing belt stretched between pulleys. Yes.
Thus, by interposing a connecting portion using a metal plate, the length of the timing belt is shortened to increase its rigidity, thereby preventing a decrease in position accuracy when the robot arm is rotated (for example, Patent Documents). 1).

JP 2004-160568 A

  However, in the robot arm shown in Patent Document 1, the rigidity is increased by using a timing belt connected to a connecting portion made of a metal plate, but the area not contacting the pulley during rotation is 50% or less of the whole, As before, the ratio of the timing belt is higher than that of the connecting portion made of a metal plate.

  Moreover, since the timing belt to be used is made of a composite material mainly composed of rubber, it is a material having elasticity. For this reason, the robot arm remains greatly affected by the elongation of the timing belt, the hysteresis, and the like, and affects the rotation of the robot arm. Therefore, there is a problem that it is difficult to ensure high positional accuracy of the robot arm.

  In order to increase the rigidity of the timing belt, when the strength, for example, the width of the timing belt is increased, the width of the timing pulley having a tooth portion that meshes with the tooth surface needs to be wide as well.

  For this reason, increasing the rigidity of the timing belt has a problem that the robot arm becomes larger and the installation space of the robot arm has to be widened.

  Accordingly, an object of the present invention is to provide a robot arm that can increase the accuracy of arm position control without increasing the size of the arm.

  The present invention includes a first arm that is rotatably attached to a robot body via a first transmission mechanism, and a working means that is rotatably attached to a distal end portion of the first arm via a second transmission mechanism. And a first connecting means for connecting the first transmission mechanism and the second transmission mechanism to transmit power, wherein the first connection means is connected to the first transmission mechanism. A first power transmission member made of a first rigid member for transmitting and receiving power or power to the first transmission mechanism; and a second for transmitting and receiving power from the second transmission mechanism or power to the second transmission mechanism. The first transmission unit includes a power transmission member, and a first coupling part and a second coupling part made of a second rigid member that connect the first power transmission member and the second power transmission member. The diameter of the mechanism is that of the second transmission mechanism. Greater than, and the length of the second power transmission member is characterized by less than the length of the first power transmission member.

  According to this invention, the first connection mechanism that transmits the power by connecting the first transmission mechanism and the second transmission mechanism constituting the robot arm is the power from the first transmission mechanism or the first transmission mechanism. A first power transmission member composed of a first rigid member that transmits and receives power to the second power transmission member, a second power transmission member that transmits and receives power from the second transmission mechanism or power to the second transmission mechanism, and The first transmission mechanism is composed of a first connecting portion and a second connecting portion made of a second rigid member that connect the one power transmission member and the second power transmission member, and the diameter of the first transmission mechanism is the second Since the diameter of the transmission mechanism is larger and the length of the second power transmission member is shorter than the length of the first power transmission member, the size of the conventional robot arm is maintained while maintaining the size of the first power transmission member. The rigidity of one connecting means can be increased, It is possible to minimize the influence of elongation and hysteresis. For this reason, position control of the robot arm can be ensured with high accuracy.

  According to this invention, the first power transmission member made of the first rigid member having the same width as that of the first transmission member can be used for the large-diameter first transmission member having a small bending stress. The rigidity of the first connecting means can be increased. Moreover, since the 1st transmission member does not have the structure by meshing | fitting, it can suppress friction and can suppress dust generation. Moreover, since the length of the 2nd power transmission member hung over the small diameter 2nd transmission member can be shortened conventionally, the dust generation which arises by meshing with a 2nd transmission member can be suppressed. .

  Further, according to the present invention, the working means is fixed to the first arm concentrically with the second transmission mechanism, a second arm fixed to the second transmission mechanism and rotatable with respect to the first arm. The third transmission mechanism and a hand rotatably attached to the tip of the second arm via a fourth transmission mechanism, and the third transmission mechanism and the fourth transmission mechanism A robot arm comprising second connecting means for connecting and transmitting power, wherein the second connecting means transmits and receives power from the fourth transmission mechanism or power to the fourth transmission mechanism. A fourth power transmission member made of a rigid member; a third power transmission member for transmitting / receiving power from or to the third transmission mechanism; the third power transmission member and the fourth power transmission A third consisting of a fourth rigid member connecting the members The fourth transmission mechanism has a diameter larger than that of the third transmission mechanism, and the third power transmission member has a length equal to that of the fourth power mechanism. It is preferable that the rotation angle ratio among the first transmission mechanism, the second transmission mechanism, and the fourth transmission mechanism is 1: 2: 1 shorter than the length of the transmission member.

  According to the present invention, the second connecting means includes a fourth power transmission member made of a third rigid member that transmits and receives power from the fourth transmission mechanism or power to the fourth transmission mechanism, and the second power transmission member. A third power transmission member that transmits and receives power from the three transmission mechanisms or power to the third transmission mechanism, and a fourth rigid member that connects the third power transmission member and the fourth power transmission member. The fourth transmission mechanism is larger in diameter than the third transmission mechanism, and the third power transmission member is longer than the fourth power transmission member. As with the first arm, while maintaining the size of the conventional robot arm, it is possible to increase the rigidity of the second connecting means and suppress the effects of elongation, hysteresis, etc. as much as possible. be able to. Therefore, when the robot arm is rotated, the hand provided at the tip of the second arm can move on a straight line with high accuracy while keeping the direction constant.

  Further, since the rotation angle ratio of the first transmission mechanism, the second transmission mechanism, and the fourth transmission mechanism is 1: 2: 1, the first arm and the second arm can be rotated by rotating the first arm. By changing the angle with the arm, the hand can move while keeping the direction constant on a straight line connecting the center of the first transmission mechanism of the first arm and the center of the fourth transmission mechanism of the second arm. For this reason, position control of the robot arm can be ensured with high accuracy.

In the present invention, it is preferable that the tension of the power transmission member is adjustable at least in the first connecting portion and the third connecting portion.
Thereby, it can set to these 1st, 3rd connection parts, adjusting predetermined tension.

Further, according to the present invention, in the first connecting portion and the second connecting portion, the center line position in the thickness direction of the first power transmission member and the center line position in the thickness direction of the second power transmission member are substantially the same. It is preferable to connect so that it may become a position. Similarly, in the third connecting portion and the fourth connecting portion, the center line position in the thickness direction of the third power transmission member and the center line position in the thickness direction of the fourth power transmission member are substantially the same position. It is preferable that they are connected as described above.
According to the present invention, when the first power transmission member and the second power transmission member having different materials and thicknesses are connected by the first and second connection portions, or the third power transmission member and the fourth power transmission member are connected to each other. When connecting at the third and fourth connecting parts, the center line position in the thickness direction is substantially the same, so the direction in which the tension applied to these power transmission members acts is almost the same position, so smooth belt transport operation It can be carried out.

  The present invention includes a first arm that is rotatably attached to a robot body via a first transmission mechanism, and a working means that is rotatably attached to a distal end portion of the first arm via a second transmission mechanism. And a first connecting means for connecting the first transmission mechanism and the second transmission mechanism to transmit power, the first transmission mechanism and the second constituting the robot arm. A first power transmission member comprising a first rigid member, wherein a first coupling means for coupling the transmission mechanism to transmit power transmits and receives power from the first transmission mechanism or power to the first transmission mechanism; A second power transmission member that transmits and receives power from the second transmission mechanism or power to the second transmission mechanism, and a second rigid member that connects the first power transmission member and the second power transmission member A first connecting portion comprising: The first transmission mechanism is larger in diameter than the second transmission mechanism, and the length of the second power transmission member is the length of the first power transmission member. Therefore, the rigidity of the first connecting means can be increased while maintaining the size of the conventional robot arm, and the influence of elongation, hysteresis and the like can be suppressed as much as possible. For this reason, position control of the robot arm can be ensured with high accuracy.

  Hereinafter, the configuration of the present invention will be described in detail based on the best mode shown in the drawings.

(Robot arm configuration)
FIG. 1 is a longitudinal sectional side view showing a main part of a robot arm. FIG. 2 is a plan view showing the main part of the robot arm.

A robot arm 1 shown in FIGS. 1 and 2 includes a first arm 50 that is rotatably attached to a base 200 of a robot body via a first transmission mechanism 2, and a second arm at the tip of the first arm 50. It mainly comprises working means 500 that is rotatably attached via the transmission mechanism 4.
The working means 500 includes a second arm 100 fixed to the second transmission mechanism 4 and rotatable with respect to the first arm 50, and a third arm fixed to the first arm 50 concentrically with the second transmission mechanism 4. The transmission mechanism 52 and a hand 252 (see FIG. 7) rotatably attached to the distal end portion of the second arm 100 via a fourth transmission mechanism 54.
Furthermore, the first transmission mechanism 2 and the second transmission mechanism 4 are connected to the robot arm 1 to transmit power by connecting the first transmission mechanism 2 and the second transmission mechanism 4, and similarly, the third transmission mechanism 52 and the fourth transmission mechanism 54 are connected. Thus, second connecting means 60 for transmitting power is provided.

(First arm)
On the base side in the first arm 50, the first transmission mechanism 2 is fixed to the base 200 of the robot body. In the present embodiment, the first transmission mechanism 2 has a flat outer peripheral surface. It is the first flat pulley.
Further, the diameter R1 of the first flat pulley 2 is larger than the diameter R2 of the second transmission mechanism 4, and in a state where the first connecting means 10 is installed, a relationship of R1: R2 = 2: 1. It has become.

The second transmission mechanism 4 is fixed to the second arm 100 by using a screw at the distal end in the first arm 50, that is, on the second arm 100 side.
In the present embodiment, the second transmission mechanism 4 is constituted by a second timing pulley having a tooth portion on the outer peripheral surface thereof.
Further, the connecting cylinder 3 is accommodated in the second timing pulley 4, and the wiring is accommodated in the connecting cylinder 3. One end of the connecting cylinder 3 is fixed to the first arm 50, and the other end is accommodated in the second arm 100. Thus, the first arm 50 and the second arm 100 are interlocked.

  Further, in the present embodiment, in the vicinity of the second timing pulley 4, there are a motor 150 as a rotational drive source, a speed reducer 151 attached to the motor 150, and a drive pulley 152 attached to the speed reducer 151. A driving belt 154 is provided between the driving pulley 152 and the second timing pulley 4.

  The first connecting means 10 includes a first power transmission member 11 made of a first rigid member, a second power transmission member 12, and a second power linking the first power transmission member 11 and the second power transmission member 12. It is comprised by the 1st connection part 20 and the 2nd connection part 25 which consist of a rigid member.

The first power transmission member 11 is formed of a first rigid member, and is formed of a steel belt in the present embodiment. The first rigid member may be a member having excellent ductility and toughness, and may be a belt other than a steel belt.
The first steel belt 11 is wound around the plane of the first flat pulley 2, and the intermediate position of the entire length is fixed to the first flat pulley 2 with a plurality of screws 16.

One end side of the first steel belt 11 is fixed to the first connecting portion 20, and the other end side is fixed to the second connecting portion 25.
The second power transmission member 12 is configured by a timing belt having a tooth surface, and the second timing belt 12 is disposed so that the tooth surface meshes with a tooth portion of the second timing pulley 4. The total length is set to a necessary minimum length calculated from the transport distance of the robot arm 1.

  In the present embodiment, the first steel belt 11, the second timing belt 12, the first connecting portion 20, and the second connecting portion 25 have substantially the same width in the axial direction.

  FIG. 3 is a plan view showing first connection means for transmitting power by connecting the first transmission mechanism and the second transmission mechanism in the first arm. FIG. 5 is a side view showing the first connecting portion (third connecting portion). FIG. 6 is a side view showing the second connecting portion (fourth connecting portion).

The first connecting portion 20 is an adjustment-side connecting portion that sandwiches one end portion of the first steel belt 11 and one end portion of the second timing belt 12 so that the interval can be adjusted.
The second connecting portion 25 is a fixed-side connecting portion that sandwiches and fixes the other end portion of the first steel belt 11 and the other end portion of the second timing belt 12.

  As shown in FIG. 5, the first connecting portion 20 includes plates 30, 31, and 32 that fix one end portions of the first steel belt 11 and the second timing belt 12, the first steel belt 11, and the second steel belt 11. The adjustment screw 145 for adjusting the tension with the timing belt 12 is a main component, and the plates 30, 31, and 32 are made of a second rigid member.

Specifically, the plate 32 is made of aluminum in the present embodiment, and is thicker than the first steel belt 11 and the second timing belt 12 in order to maintain its strength. On the aluminum plate 32, a groove portion 32a is formed on one end side thereof, and the groove portion 32a is arranged so that a tooth surface of one end portion of the second timing belt 12 is engaged with the groove portion 32a.
Further, the second timing belt 12 is sandwiched between an aluminum plate 32 and a stainless steel plate 31 and fixed using a plurality of screws.

On the other end side of the aluminum plate 32, a stainless steel plate 30 is fixed using a plurality of screws. The stainless steel plate 30 is formed with a long hole 30b along the longitudinal direction through which a plurality of screws pass. Thereby, the overlap margin of the stainless steel plate 30 and the aluminum plate 32 can be adjusted.
In FIG. 5, a plurality of screws are formed in one row in the width direction. However, in order to clarify the relationship between the screws and the long holes 30 b, the plurality of screws are limited to one row in the width direction. Is not to be done.

  Further, the other end of the stainless steel plate 30 is screwed to one end of the first steel belt 11 with a shim 40 interposed. The shim 40 adjusts the height in the thickness direction between the first steel belt 11 and the second timing belt 12, and the center line C between the first steel belt 11 and the second timing belt 12. The distance from is about the same. The number of shims 40 is not limited.

  Further, the stainless steel plates 30 and 31 are formed with rising portions 30a and 31a on opposite sides, and an adjusting screw 145 is screwed to the rising portions 30a and 31a. The adjustment screw 145 makes it possible to adjust the distance between the stainless steel plates 30 and 31, and the first steel belt 11, the second timing belt 12, and the like along the long holes 30 b formed in the stainless steel plate 30. The tension can be adjusted.

  As shown in FIG. 6, the second connecting portion 25 mainly includes plates 33 and 34 that sandwich and fix the other ends of the first steel belt 11 and the second timing belt 12. Consists of a second rigid member. In addition, the 2nd rigid member should just be a member excellent in ductility and toughness.

  In the present embodiment, the plate 33 is made of stainless steel, and the first steel belt 11 and the second timing belt 12 are fixed to both ends of the stainless steel plate 33 using a plurality of screws, respectively. The first steel belt 11 is fixed to the stainless steel plate 33 with a shim 40 interposed therebetween. The shim 40 adjusts the height in the thickness direction, and is adjusted so that the distance from the center line C to the second timing belt 12 is substantially the same using one or a plurality of shims 40. ing.

  The second timing belt 12 is sandwiched between an aluminum plate 34 and a stainless steel plate 33 and fixed using a plurality of screws. As shown in FIG. 6, the flat side of the second timing belt 12 is disposed on a stainless steel plate 33, and an aluminum plate 34 with grooves is formed on the tooth surface side of the second timing belt 12. Has been placed. The toothed surface of the second timing belt 12 is fixed to the groove of the aluminum plate 34 using a plurality of screws.

Returning to FIG. 3, the first arm 50 rotates clockwise (CW direction) or counterclockwise (CCW direction) with respect to the fixed first flat pulley 2 by driving the motor 150. However, the positions when the first connecting means 10 is rotated clockwise (CW direction) and when it is rotated counterclockwise (CCW direction) are indicated by dotted lines.
When the 1st connection means 10 rotates counterclockwise (CCW direction), the 1st steel belt 11 rotates to the code | symbol 16A, the 1st connection part 20 moves to the code | symbol 20A, and the 2nd connection part 25 moves to 25A.
Moreover, when the 1st connection means 10 rotates clockwise (CW direction), the 1st steel belt 11 rotates to the code | symbol 16B, the 1st connection part 20 moves to the code | symbol 20B, and a 2nd connection The unit 25 moves to the reference numeral 25B.

  As described above, the first flat pulley 2 and the second timing pulley 4 are formed in the first flat pulley 2 because the ratio of the diameters (the number of teeth) is R1: R2 = 2: 1. The first flat pulley 2 rotates about 1/4 until the fixed portion 16 reaches 16A. During this time, the second timing pulley 4 rotates about ½. Therefore, the length of the second timing belt 12 is a length that moves in the clockwise direction (CW direction) and the counterclockwise direction (CCW direction) to the length (about ½ rotation) that meshes with the second timing pulley 4. The total length is about 3/2 rotations. That is, the total length is set to a necessary minimum length calculated from the transport distance of the robot arm 1.

As shown in FIG. 2, a plurality of ribs 219 are formed in the first arm 50 at predetermined intervals, so that cross-sectional deformation can be suppressed, and the vertical rigidity of the first arm 50 shown in the figure is increased. Can be done.
Further, by forming these ribs 219, the thickness of the first arm 50 is reduced and the weight is reduced.

Each rib 219 is formed with three holes 220, 220, and 221 in the longitudinal direction, and the middle hole 221 is a through hole for wiring in the first arm 50 for arranging an electric wire or the like. Further, on both sides of the wiring through hole, the first steel belt 11, the second timing belt 12, and the through holes 220 and 220 through which the first and second connecting portions 20 and 25 pass are formed.
In the state where one of the first and second connecting portions 20 and 25 is cut off, the first connecting means 10 passes through the through holes 220 and 220 and connects the connecting portions cut off after the penetration. ing.
Further, the first flat pulley 2 is formed with a plurality of holes 2a penetrating in the axial direction evenly in the circumferential direction, and the weight of the first arm 50 is reduced by reducing the weight. .

(Working method)
The working means 500 provided at the distal end of the first arm 50 is fixed to the second timing pulley 4 and is rotatable with respect to the first arm 50. The second timing pulley 4 A third transmission mechanism 52 concentrically fixed to the first arm 50, a hand 252 (see FIG. 7) rotatably attached to the tip of the second arm 100 via a fourth transmission mechanism 54, The third transmission mechanism 52 and the fourth transmission mechanism 54 are connected to each other to constitute a second connection means 60 for transmitting power.

A connecting cylinder 3 concentric with the second timing pulley 4 and extending from the first arm 50 is housed on the base side (first arm 50 side) in the second arm 100. A third transmission mechanism 52 is fixed to the other end.
In the present embodiment, the third transmission mechanism 52 is composed of a timing pulley having a tooth portion on its outer peripheral surface.

A fourth transmission mechanism 54 is provided at the distal end of the second arm 100 so as to be rotatable with respect to the second arm 100 via a bearing.
A hand 525 (see FIG. 7) for transporting a workpiece is attached to the distal end portion of the fourth transmission mechanism 54 so as to be rotatable integrally with the fourth transmission mechanism 54.
In the present embodiment, the fourth transmission mechanism 54 is a flat pulley whose outer peripheral surface is a flat surface.
Furthermore, the diameter R4 of the fourth flat pulley 54 is larger than the diameter R3 of the third timing pulley 52, and in a state where the second connecting means 60 is installed, R3: R4 = 1: 2. It has become a relationship.

  The second connecting means 60 includes a fourth power transmission member 62 made of a third rigid member, a third power transmission member 61, and a fourth power transmission member 61 and a fourth power transmission member 62. The third connecting portion 70 and the fourth connecting portion 75 are made of a rigid member.

  The third power transmission member 61 is configured by a timing belt having a tooth surface, and the third timing belt 61 is disposed so that the tooth surface meshes with a tooth portion of the third timing pulley 52, The total length is set to a necessary minimum length calculated from the transport distance of the robot arm 1.

The fourth power transmission member 62 is formed of a rigid member having excellent ductility and toughness, and is formed of a steel belt in the present embodiment. The fourth steel belt 62 is wound around the plane of the fourth flat pulley 54, and an intermediate position of the entire length thereof is fixed on the outer peripheral surface of the fourth flat pulley 54 with a plurality of screws 66.
One end side of the fourth steel belt 62 is fixed to the third connecting portion 70, and the other end side is fixed to the fourth connecting portion 75.

FIG. 4 is a plan view showing second connection means for transmitting power by connecting the third transmission mechanism and the fourth transmission mechanism in the second arm constituting the working means.
FIG. 5 is a side view showing the first connecting portion (third connecting portion). FIG. 6 is a side view showing the second connecting portion (fourth connecting portion).
The third connecting portion 70 and the fourth connecting portion 75 have substantially the same configuration as the first connecting portion 20 and the second connecting portion 25 of the first arm 50 described above, and therefore are parenthesized in FIGS. It is filled in as the code inside. Therefore, detailed description here is omitted.
Further, as shown in FIG. 4, in the second arm 100, the lengths of the third connecting portion 70 and the fourth connecting portion 75, that is, the length of the connecting portion made of the plate is the connection of the first arm 50. It is longer than the length of the part. That is, when the second arm 100 is rotated, the length is such that it does not contact the third timing pulley 52 and the fourth flat pulley 54, the length of the third timing belt 61 is shortened, and the strength of the second connecting means 60 is increased. Is high.

Returning to FIG. 4, the second arm 100 receives the rotation of the first arm 50, and rotates clockwise (CW direction) or counterclockwise (CCW direction) with respect to the connecting cylinder 3 and the fixed third timing pulley 52. ), But the position when the second connecting means 60 is rotated clockwise (CW direction) and when it is rotated counterclockwise (CCW direction) is indicated by a dotted line. Yes.
When the second connecting means 60 rotates clockwise (CW direction), the fourth steel belt 62 rotates to the reference numeral 66A, the third connecting part 70 moves to the reference numeral 70A, and the fourth connecting part 75. Moves to 75A.
When the second connecting means 60 rotates counterclockwise (CCW direction), the fourth steel belt 62 rotates to the reference numeral 66B, and the third connecting portion 70 moves to the reference numeral 70B. The connecting portion 75 moves to the reference numeral 75B.

  As described above, the third timing pulley 52 and the fourth flat pulley 54 are formed on the fourth flat pulley 54 because the ratio of the diameters (the number of teeth) is R3: R4 = 1: 2. When the fixed portion 66 rotates about 1/4, the third timing pulley 52 rotates about 1/2. Therefore, the length of the third timing belt 61 is a length that moves in the clockwise direction (CW direction) and the counterclockwise direction (CCW direction) to the length (about 1/2 rotation) that meshes with the third timing pulley 52. The total length is about 3/2 rotations. That is, the total length is set to a necessary minimum length calculated from the transport distance of the robot arm 1.

As shown in FIG. 2, a plurality of ribs 210 are formed in the second arm 100 at predetermined intervals, so that cross-sectional deformation can be suppressed, and the rigidity of the second arm 100 in the illustrated vertical direction is increased. Can be done. Further, by forming these ribs 210, the thickness of the second arm 100 is reduced and the weight is reduced.
Each rib 210 is formed with three holes 211, 211, 212 in the longitudinal direction, and the middle hole 212 is a through hole for wiring in which an electric wire or the like is arranged in the arm. Furthermore, the third timing belt 61, the fourth steel belt 62, and the through holes 211, 211 through which the third and fourth connecting portions 70, 75 pass are formed on both sides of the wiring through hole.
The second connecting means 60 passes through the through holes 211 and 211 in a state where one of the third and fourth connecting parts 70 and 75 is cut off, and connects the connecting parts cut off after the penetration. It has become.

  Further, as shown in FIG. 2, the fourth flat pulley 54 has a plurality of holes 54a penetrating in the axial direction evenly in the circumferential direction, and the weight of the second arm 100 can be reduced by reducing the weight. It tries to make it.

(Robot arm movement)
The operation of the robot arm 1 described above will be described below.
The robot arm 1 is driven by a motor 150 disposed in the vicinity of the second timing pulley 4 in the first arm 50. The rotation of the motor 150 is transmitted to the drive pulley 152 via the speed reducer 151.
The rotation of the drive pulley 152 is transmitted to the second timing pulley 4 via the drive belt 154. The rotation of the second timing pulley 4 is transmitted to the first flat pulley 2 via the first connecting portion 20 and the second connecting portion 25.

Further, as the second timing pulley 4 rotates, the second arm 100 rotates relative to the first arm 50 and the third timing pulley 52 rotates relative to the second arm 100.
When the third timing pulley 52 rotates with respect to the second arm 100, the fourth flat pulley 54 rotates with respect to the second arm 100 and the hand 252 rotates.

  Here, the distance between the rotation centers of the first flat pulley 2 and the second timing pulley 4 and the distance between the rotation centers of the third timing pulley 52 and the fourth flat pulley 54 are the same length.

Further, the first flat pulley 2 and the second timing pulley 4 have a ratio of diameter (number of teeth) of 2: 1 in a state where the first steel belt 11 and the second timing belt 12 are wound. It is provided to become.
Similarly, the third timing pulley 52 and the fourth flat pulley 54 have a ratio of diameter (number of teeth) of 1: 3 in a state where the third timing belt 61 and the fourth steel belt 62 are wound. 2 is provided. For this reason, the rotation angle ratio of the first flat pulley 2, the second timing pulley 4, and the fourth flat pulley 54 is 1: 2: 1.

  From the above, the first flat pulley 2 and the second timing pulley 4 of the first arm 50 (that is, the third timing pulley 52 of the second arm 100) and the fourth flat pulley 54 of the second arm 100. The rotation angle ratio between the first arm 50 and the second arm 100 is changed by rotating the first arm 50 so that the first arm 50 has a first rotation angle ratio of 1: 2: 1. The hand 252 moves on a straight line connecting the center of the flat pulley 2 and the center of the fourth flat pulley 54 of the second arm 100 while keeping the direction constant.

FIG. 7 is a plan view showing a double arm type articulated robot using a robot arm to which the present invention is applied.
In this double arm type multi-joint robot, the above-described robot arm 1 is arranged on the base 200 of the robot body, for example, as shown in FIG. According to this double-arm type articulated robot, one robot arm is in a load state that is an operation for picking up a workpiece, and the other robot arm is in an unload state that is an operation for pulling out another workpiece. These two operations can be performed simultaneously.

  In addition, as described above, the two robot arms have a rotation angle ratio of 1: 2: 1 between the first transmission mechanism of the first arm 50, the second transmission mechanism, and the fourth transmission mechanism of the second arm 100. By rotating the first arm 50, the angle between the first arm 50 and the second arm 100 changes, and the center of the first transmission mechanism of the first arm 50 and the fourth transmission mechanism of the second arm 100 are changed. The hand 252 moves on a straight line connecting the center with a constant direction.

  Further, in FIG. 7, the double arm type articulated robot is provided so that the robot arm can be moved up and down and the articulated robot can run.

(Other embodiments)
The above-described embodiment is an example of a preferred embodiment of the present invention, but is not limited thereto, and various modifications can be made without departing from the gist of the present invention.
For example, although the timing belt is used for the second power transmission member 12 and the third power transmission member 61 in the present embodiment, the present invention is not limited to this, and a chain or the like may be used.

  In the above-described embodiment, the arms 50 and 100 are provided with the ribs 219 and 210. However, the ribs 219 and 210 are not limited to the shape of the ribs, and are not provided when the load is not so large. Also good.

  In the present embodiment, the first to fourth connecting portions 20, 25, 70, and 75 are provided to adjust the tension of the first connecting means 10 and the second connecting means 60. Without using, an idler pulley may be provided on the steel belts 11 and 62 side to adjust the tension. When the idler pulley is provided, the first flat pulley 2 and the fourth flat pulley are increased by increasing the angle of the steel belts 11 and 62 that are in contact with the first flat pulley 2 and the fourth flat pulley 54. The rotation angle of 54 increases and the transport distance of the arm increases.

Furthermore, although the motor 150 is provided in the vicinity of the second timing pulley 4 of the first arm 50 in the above-described embodiment, the present invention is not limited to this, and the motor 150 may be built in the robot body. In this case, the first arm 50 is driven by the motor 150 to transmit power from the first flat pulley 2 to the second timing pulley 4, the third timing pulley 52, and the fourth flat pulley 54. Alternatively, the motor 150 may be provided on the second arm 100 to drive the fourth flat pulley 54.
In this case, power is transmitted from the fourth flat pulley 54 to the third timing pulley 52, the second timing pulley 4, and the first flat pulley 2.

  Moreover, in this Embodiment, although the 2nd connection part 25 and the 4th connection part 75 were the fixed side connection parts which did not give the adjustment function, the 1st connection part 20 and the 3rd connection part 70, Similarly, it may be an adjustment side connecting portion having a tension adjusting function.

(Effect of this embodiment)
According to the present embodiment, the first connecting means 10 for transmitting the power by connecting the first flat pulley 2 and the second timing pulley 4 constituting the robot arm 1 is The first steel belt 11 made of the first rigid member that transmits and receives power or power to the first flat pulley 2 and power from the second timing pulley 4 or power to the second timing pulley 4 It comprises a second timing belt 12 to be exchanged, and a first connecting portion 20 and a second connecting portion 25 made of a second rigid member for connecting the first steel belt 11 and the second timing belt 12. In addition, the diameter of the first flat pulley 2 is larger than the diameter of the second timing pulley 4, and the length of the second timing belt 12 is shorter than the length of the first steel belt 11. Runode, while maintaining the size of the conventional robot arm 103, it is possible to increase the rigidity of the first coupling means 10, it is possible to minimize the influence of the elongation and hysteresis. For this reason, the position control of the robot arm 1 can be ensured with high accuracy.

  In addition, according to the present embodiment, the second connecting means 60 is the fourth steel made of the third rigid member that transmits or receives the power from the fourth flat pulley 54 or the power to the fourth flat pulley 54. A belt 62, a third timing belt 61 that transmits and receives power from the third timing pulley 52 or power to the third timing pulley 52, and the third timing belt 61 and the fourth steel belt 62. It is composed of a second connecting portion 70 and a fourth connecting portion 75 made of a fourth rigid member to be connected, and the diameter of the fourth flat pulley 54 is larger than the diameter of the third timing pulley 52, and Since the length of the fourth timing belt 61 is shorter than the length of the third steel belt 62, the size of the conventional robot arm 103 must be maintained in the same manner as the first arm 50. , It is possible to increase the rigidity of the first coupling means 60, I am possible to minimize the influence of the elongation and hysteresis. For this reason, when the robot arm 1 is rotated, the position of the hand 252 provided at the tip of the second arm 100 can be controlled with high accuracy while keeping the direction on a straight line constant.

Further, since the rotation angle ratio among the first flat pulley 2, the second timing pulley 4, and the fourth flat pulley 54 is 1: 2: 1, the first arm 50 is turned to turn the first The angle between the arm 50 and the second arm 100 changes, and the hand moves on a straight line connecting the center of the first flat pulley 2 of the first arm 50 and the center of the fourth flat pulley 54 of the second arm 100. 252 can move while keeping the direction constant. As a result, it is possible to increase the positional accuracy of the work placed and transported on the hand 252 and to perform stable transport.
Furthermore, since the rigidity of the 1st connection means 10 and the 2nd connection means 60 can be improved, the hand 252 can move on a straight line with a sufficient precision.

  In the present embodiment, it is preferable that at least the first connecting portion 20 and the third connecting portion 75 are each provided with an adjusting portion that adjusts the tension of each power transmission member. Thereby, these 1st, 3rd connection parts 20 and 75 can be set, adjusting predetermined tension.

  According to the present embodiment, the first steel belt 11 having a width substantially the same as that of the first flat pulley 2 having a small bending stress and a large diameter can be wound around the first flat pulley 2. The rigidity of the connecting means 10 can be increased. In addition, since the length of the third timing belt 12 stretched to the small-diameter second timing pulley 4 side can be made shorter than the conventional belt, the meshing with the small-diameter second timing pulley 4 is possible. It is possible to suppress dust generation caused by.

Further, in the present embodiment, the first connecting portion 20 and the second connecting portion 25 are arranged such that the center line C position in the thickness direction of the first steel belt 11 and the center line C position in the thickness direction of the second timing belt 12. Are preferably connected so as to be in substantially the same position. Similarly, the third connecting portion 70 and the fourth connecting portion 75 are substantially in the same position as the center line C position in the thickness direction of the third timing belt 61 and the center line C position in the thickness direction of the fourth steel belt 62. It is connected so that
With this configuration, when the first steel belt 11 and the second timing belt 12 of different materials and thicknesses are connected by the first connecting portion 20 and the second connecting portion 25, or the third timing belt 61 and the fourth timing belt 12 are connected. When the steel belt 62 is connected by the third connecting portion 70 and the fourth connecting portion 75, the center line C position in the thickness direction is substantially the same, so these power transmission members (steel belts 11, 62, timing belt) 12, 61), the direction in which the tension is applied is substantially the same position, so that the direction of the tension and the direction in which the power transmission member moves are substantially the same, and a smooth belt conveyance operation can be performed.

  According to the present embodiment, the first steel belt 11 is hung on the large-diameter first flat pulley 2 side having a small bending stress so as to have the same length as the rotation range of the first arm 50. This increases the rigidity of the power transmission system. Further, since the first steel belt 11 is fixed on the outer peripheral surface of the first flat pulley 2, there is no deviation in the rotation of the first steel belt 11, and the power transmission member (steel belt 11 62, and the timing belts 12, 61) are equally applied, so that power can be transmitted efficiently and durability can be improved.

  In the present embodiment, the width of the first steel belt 11 and the second timing belt 12 and the width of the first flat pulley 2 and the second timing pulley 4 can be made substantially the same. In addition, the width of the third timing belt 61 and the fourth steel belt 62 and the width of the third timing pulley 52 and the fourth flat pulley 54 can be made substantially the same. For this reason, the moment excess concerning the member which supports each transmission mechanism can be made constant.

  In addition, according to the present embodiment, the lengths of the second timing belt 12 and the third timing belt 61 can be set to the necessary minimum length calculated from the transport distance of the robot arm 1. Dust generation that occurs when the second timing belt 12 moves while meshing with the second timing pulley 4 when the arm 1 rotates, or when the third timing belt 61 moves while meshing with the third timing pulley 52. Can be suppressed.

  Since the second timing belt 12 and the third timing belt 61 to be used are made of a composite material mainly composed of rubber, there is a problem that harmful gas is generated in a vacuum environment. Since the lengths of the second and third timing belts 12 and 61 are set to the minimum necessary length, generation of harmful gas can be suppressed as compared with the conventional case.

  In the present embodiment, at least the first connecting portion 20 and the third connecting portion 70 are provided with adjustable tensions of the power transmission members (steel belts 11 and 62, timing belts 12 and 61). The tension can be easily adjusted so that the power transmission members (steel belts 11, 62, timing belts 12, 61) do not come off from the transmission mechanisms (flat pulleys 2, 54, timing pulleys 4, 52). it can.

It is a longitudinal cross-sectional side view which shows the principal part of a robot arm. It is a general view which shows the principal part of a robot arm. It is a top view which shows a 1st connection means. It is a top view which shows a 2nd connection means. It is a side view which shows a 1st connection part (3rd connection part). It is a side view which shows a 2nd connection part (4th connection part). It is a top view which shows the double arm type | mold articulated robot using the robot arm to which this invention is applied. It is a longitudinal cross-sectional side view which shows the conventional robot arm.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Robot arm 2 1st transmission mechanism 4 2nd transmission mechanism 10 1st connection means 11 1st power transmission member 12 2nd power transmission member 20 1st connection part 25 2nd connection part 50 1st arm 60 2nd connection means 61 Third power transmission member 62 Fourth power transmission member 70 Third connection portion 75 Fourth connection portion 100 Second arm 250 Base 500 Working means

Claims (5)

The first arm is rotatably attached to the robot body via the first transmission mechanism, and the working means is rotatably attached to the tip of the first arm via the second transmission mechanism. In addition, in the robot arm comprising the first connecting means for connecting the first transmission mechanism and the second transmission mechanism to transmit power,
The first coupling means includes a first power transmission member made of a first rigid member that transmits and receives power from the first transmission mechanism or power to the first transmission mechanism, and power from the second transmission mechanism. Alternatively, a second power transmission member that transmits and receives power to the second transmission mechanism, and a first coupling portion that includes the second rigid member that connects the first power transmission member and the second power transmission member, and the second And a diameter of the first transmission mechanism is larger than a diameter of the second transmission mechanism, and a length of the second power transmission member is larger than a length of the first power transmission member. Short robot arm A second arm fixed to the second transmission mechanism and rotatable with respect to the first arm; and a third transmission mechanism concentric with the second transmission mechanism and fixed to the first arm. And a hand rotatably attached to the tip of the second arm via a fourth transmission mechanism, and the third transmission mechanism and the fourth transmission mechanism are connected to transmit power. A robot arm comprising second connecting means for
The second connecting means is a fourth power transmission member comprising a third rigid member for transmitting / receiving power from the fourth transmission mechanism or power to the fourth transmission mechanism, and power from the third transmission mechanism. Alternatively, a third power transmission member for transmitting and receiving power to the third transmission mechanism, and a third connecting portion and a fourth fourth member made of a fourth rigid member for connecting the third power transmission member and the fourth power transmission member. And a diameter of the fourth transmission mechanism is larger than a diameter of the third transmission mechanism, and a length of the third power transmission member is larger than a length of the fourth power transmission member. The robot arm according to claim 1, wherein the rotation angle ratio of the first transmission mechanism, the second transmission mechanism, and the fourth transmission mechanism is 1: 2: 1.   3. The robot arm according to claim 1, wherein a tension of the power transmission member is adjustable at least in the first connection part and the third connection part. 4.   The first connecting portion and the second connecting portion are connected such that the center line position in the thickness direction of the first power transmission member and the center line position in the thickness direction of the second power transmission member are substantially the same position. The robot arm according to any one of claims 1 to 3, wherein The third connecting portion and the fourth connecting portion are connected so that the center line position in the thickness direction of the third power transmission member and the center line position in the thickness direction of the fourth power transmission member are substantially the same position. The robot arm according to claim 2 or 3, wherein

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