JP7440082B2 - Actuators and robots - Google Patents

Description

The present invention relates to an actuator and a robot.

An actuator that uses a ball screw to linearly move an actuating rod in an axial direction has been put into practical use. For example, Cited Document 1 discloses an actuator in which an actuating rod is provided in the center, and when the ball screw shaft is rotated by a motor, a nut screwed onto the ball screw shaft moves the actuating rod in the axial direction.

Publication number 2-5143

In the actuator of Patent Document 1, as the amount of movement set for the actuating rod increases and the length of the actuator in the longitudinal direction increases, the bending rigidity of a single actuating rod tends to be insufficient and vibrations tend to occur. On the other hand, although FIG. 6 of Cited Document 1 discloses an actuator provided with a pair of rods, the bending rigidity in directions other than the direction in which the rods are lined up can be greater than that of a single actuating rod. It is not enough to suppress the vibrations of objects, and vibrations still tend to occur.

The present invention was made in order to solve the above-mentioned problems, and an object of the present invention is to provide an actuator and a robot that can suppress vibration during operation by increasing the bending rigidity of the rod. .

The actuator according to the present invention includes a ball screw shaft that rotates by transmitting the rotational motion of an output shaft of a motor, a ball screw nut provided on the ball screw shaft, and a first holder to which the ball screw nut is attached. and a second holding part overlapping the first holding part, and a sliding part that moves linearly in accordance with the rotational movement of the ball screw shaft, and a tubular member having one end held by the first holding part. a first rod, a tubular second rod having one end held by the second holding portion, and a tip bracket connecting the first rod and the second rod at their other ends, and The screw shaft passes through the first holding portion, and one end thereof is rotatably supported by the inner circumferential surface of the first rod.

The second holding part has a through hole connected to the hollow part formed in the second rod, and the tip bracket has an opening connected to the hollow part formed in the second rod. A passage may be formed for passing wiring from the second holding part, through the second rod, and through the tip bracket.

The slide portion may be provided with a wiring fixture for fixing an intermediate portion of the wiring passing through the passage.

It further includes a tubular third rod whose one end is held by the second holding part, and when viewed from the direction in which the sliding part moves linearly, the first rod, the second rod, and the third rod each have may be arranged so that the center of is located at the vertex of the isosceles triangle.

The second holding part has a through hole connected to the hollow part formed in the third rod, and the tip bracket has an opening connected to the hollow part formed in the third rod. A passage may be formed for passing wiring from the second holding part, through the third rod, and through the tip bracket.

The slider may further include a base body that supports the slide portion in a linearly movable manner, and a rolling element may be interposed between the slide portion and the base body to be continuous and roll along the moving direction of the slide portion. .

The one end of the ball screw shaft may be provided with a steadying member that comes into contact with an inner circumferential surface of the first rod to suppress vibration of the first rod.

The robot according to the present invention includes the above-mentioned actuator in which a second actuator is attached to the tip bracket, and the wiring of the second actuator is led from the tip bracket through at least a hollow part of the second rod. .

According to the present invention, it is possible to provide an actuator and a robot that can suppress vibration during operation by increasing the bending rigidity of the rod.

FIG. 1 is a perspective view of a robot to which an actuator according to an embodiment of the present invention is applied. FIG. 1 is an exploded perspective view of an actuator according to an embodiment of the present invention. FIG. 3 is a cross-sectional view of the actuator taken along section line III-III in FIG. 2. FIG. 3 is a cross-sectional view of the actuator taken along section line IV-IV in FIG. 2. FIG. 2 is a perspective view of a drive mechanism included in an actuator according to an embodiment of the present invention. FIG. 6 is a side view of the drive mechanism as seen from arrow VI in FIG. 5; FIG. 2 is an exploded perspective view of a drive mechanism included in an actuator according to an embodiment of the present invention. FIG. 2 is an exploded perspective view of a drive mechanism included in an actuator according to an embodiment of the present invention. FIG. 8 is an exploded perspective view of the drive section shown in FIG. 7; FIG. 8 is an exploded perspective view of the urging section shown in FIG. 7; FIG. 8 is a sectional view of the mainspring mechanism shown in FIG. 7 in a released state. FIG. 8 is a sectional view of the mainspring mechanism shown in FIG. 7 in a winding state. FIG. 8 is an exploded perspective view of the speed increasing section shown in FIG. 7; 7 is a cross-sectional view of the drive mechanism taken along section line XIV-XIV in FIG. 6. FIG. 7 is a cross-sectional view of the drive mechanism taken along cutting line XV-XV in FIG. 6. FIG. 7 is a cross-sectional view of the drive mechanism taken along section line XVI-XVI in FIG. 6. FIG. FIG. 4 is an enlarged view of the "XVII" section in FIG. 3. FIG. 4 is an enlarged view of the "XVIII" section in FIG. 3. FIG. 3 is a perspective view of the slide portion shown in FIG. 2; An enlarged view of the "XX" section in FIG. 4. FIG. 5 is an enlarged view of the "XXI" section in FIG. 4. 3 is a sectional view of the actuator taken along section line XXII-XXII in FIG. 2. FIG. FIG. 3 is a diagram for explaining the operation of the actuator, and is a side view showing how the rod gradually protrudes ((a) to (c)).

DESCRIPTION OF THE PREFERRED EMBODIMENTS An actuator and a robot according to embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, orthogonal coordinates are defined in which the X, Y, and Z axes are defined, and the description will be made with reference to these orthogonal coordinates as appropriate. Here, the +Z-axis direction is upward, and the -Z-axis direction is downward. That is, the X-axis and Y-axis are parallel to the horizontal direction, and the Z-axis is parallel to the vertical direction.

(Overview of robot 1 to which Z-axis actuator 100 is applied)
As shown in FIG. 1, a robot 1 to which an actuator 100 according to an embodiment of the present invention is applied includes an X-axis actuator 10 whose longitudinal direction is arranged along the X-axis, and an X-axis actuator 10 whose longitudinal direction is arranged along the Y-axis. a Y-axis actuator 20 arranged along the Z-axis; a Z-axis actuator 100 whose longitudinal direction is arranged along the Z-axis; a wrist unit 30 provided at one end of the Z-axis actuator 100; A gripper 40 provided in the unit 30 is provided. Further, in this embodiment, the wrist unit 30 and the gripper 40 are installed, but the present invention is not limited to this. It may also be a wrist unit, another tool other than a gripper, an electronic device, or an air-powered device.

The X-axis actuator 10 includes an X-axis ball screw (not shown) arranged along the X-axis direction, and an X-axis motor (not shown) that drives the X-axis ball screw. The XY bracket 11 is fixed to an X-axis ball screw nut (not shown), and the XY bracket 11 can be moved along the X-axis by controlling the rotation direction and rotation amount of the output shaft of the X-axis motor. It can be moved in a straight line and stopped at a desired position. Note that the XY bracket 11 holds an actuator 20 for the Y axis. Thereby, by moving the XY bracket 11 along the X-axis direction, the Y-axis actuator 20 can be moved along the X-axis direction.

The Y-axis actuator 20 includes a Y-axis ball screw (not shown) arranged along the Y-axis direction, and a Y-axis motor (not shown) that drives the Y-axis ball screw. The YZ bracket 21 is fixed to a Y-axis ball screw nut (not shown), and by controlling the rotation direction and rotation amount of the output shaft of the Y-axis motor, the YZ bracket 21 can be moved along the Y-axis. It can be moved in a straight line and stopped at a desired position. Note that the YZ bracket 21 holds a Z-axis actuator 100. Thereby, by moving the YZ bracket 21 along the Y-axis direction, the Z-axis actuator 100 can be moved along the Y-axis direction.

As shown in FIGS. 3 and 4, the Z-axis actuator 100 includes a Z-axis ball screw shaft 101 that is arranged along the Z-axis direction, and a Z-axis that drives the Z-axis ball screw shaft 101. It has inside thereof a motor 120 and a slide portion 160 to which a ball screw nut 188 screwed onto the ball screw shaft 101 is attached. The slide portion 160 includes a first rod 175, a second rod 176, and a third rod 177 (hereinafter these rods will be collectively referred to as rods), each of which has a cylindrical shape and whose ends in the -Z axis direction are connected by a tip bracket 190. 175, 176, 177). Note that the wrist unit 30 shown in FIG. 1 is attached to the tip bracket 190. As a result, the motor 120 rotationally drives the ball screw shaft 101, so that the slide portion 160 moves along the Z-axis direction. As the slide portion 160 moves in the Z-axis direction, the plurality of rods 175, 176, 177 and the wrist unit 30 shown in FIG. 1 move along the Z-axis direction.

As shown in FIG. 1, the wrist unit 30 is attached to the lower end of the Z-axis actuator 100. For example, the wrist unit 30 rotates in the R direction. This rotation in the R direction is rotation around the Z axis. Furthermore, the wrist unit 30 has a rotating portion 30a that is rotatable in the B direction (around the X axis).

As shown in FIG. 1, the gripper 40 is attached to the rotating portion 30a of the wrist unit 30 so as to be rotatable in the T direction (around the Z axis). Therefore, the gripper 40 is controlled to move arbitrarily within the three-dimensional space of the X-axis, Y-axis, and Z-axis by the actuator 10 for the X-axis, the actuator 20 for the Y-axis, and the actuator 100 for the Z-axis. , are rotated by the wrist unit 30 in the R direction, B direction, and T direction. Furthermore, the gripper 40 has two claws 41 and 42 for gripping an article. By changing the distance between the two claws 41 and 42, it is possible to grip an article or release a gripped article. The robot 1 operates, for example, as a transport robot that transports an article gripped by a gripper 40 to a desired position using various actuators.

(Configuration of Z-axis actuator 100)
Next, the configuration of the Z-axis actuator 100 will be described in detail. As shown in FIG. 2, the actuator 100 includes a base 180 on which various parts are installed, and a cover 181 that is attached to the base 180 and covers the various parts. The base 180 and the cover 181 constitute the casing 50 of the actuator 100, and form an accommodation space for accommodating various parts of the actuator 100. As will be described later, the base 180 supports an accommodating section 198 that accommodates the biasing section 112 (FIGS. 3 and 4) and a slide section 160 that moves along the Z-axis direction so as to be movable along the Z-axis direction. It includes a base body 199 and a housing 200 that supports a plurality of rods 175, 176, 177 so as to be movable along the Z-axis direction.

As shown in FIG. 3, the actuator 100 includes a drive mechanism 110 that rotationally drives the ball screw shaft 101 in a portion on the +Z-axis direction side (the upper part of the actuator 100). As shown in FIGS. 5 and 6, the drive mechanism 110 includes a drive section 111 that outputs power for rotationally driving the ball screw shaft 101 (FIG. 3), and a drive section 111 that urges the ball screw shaft 101 in a predetermined rotational direction. and a speed increasing part 113 that speeds up the rotation of the urging part 112.

As shown in FIGS. 7 and 8, the drive section 111 includes a motor 120, a pulley 121 connected to the motor 120, and a fitting 122 for attaching the motor 120 to the speed increasing section 113.

As shown in FIG. 9, the motor 120 is, for example, a stepping motor, and includes a rotor, a stator, an encoder, and the like. Electric power is supplied to the motor 120 from a power source via a cable of a cable unit (not shown). The cable unit also includes a cable for supplying power to the motor 120 from the outside, inputting/outputting control signals, etc., and a cable guide for protecting the cable. By supplying electric power to the motor 120, the rotor of the motor 120 rotates. This rotational motion of the rotor is output to an output shaft 123 extending along the Z-axis direction.

The pulley 121 is fixed to the output shaft 123 by a screw 124 screwed in from the outside. Thereby, the pulley 121 rotates together with the output shaft 123.

The fixture 122 is formed by bending a metal plate, for example. The mounting fixture 122 includes a rectangular flat plate portion 122a fixed to the motor 120 by screws 125, two standing portions 122b standing perpendicularly from opposite sides of the flat plate portion 122a, and an outer side extending from the end of the standing portion 122b. The flange portion 122c is formed toward the flange portion 122c. An opening 122d is formed in the center of the flat plate portion 122a. The pulley 121 is attached to the output shaft 123 of the motor 120, passing through the opening 122d. As a result, the pulley 121 is accommodated in a space surrounded by the flat plate portion 122a, the two upright portions 122b, and the speed increasing portion 113 shown in FIG. Furthermore, as shown in FIG. 9, two elongated holes 122e whose longitudinal directions face the X-axis direction are formed in each of the two flange portions 122c in parallel in the X-axis direction. As shown in FIGS. 7 and 8, the flange portion 122c is fixed in contact with the speed increasing portion 113 by screws 126 inserted through the elongated holes 122e. By making the hole through which the screw 126 is inserted into the elongated hole 122e in this way, the mounting position of the drive section 111 relative to the speed increasing section 113 can be adjusted in the direction along the X-axis direction. Thereby, the tension of the timing belt 166, which will be described later and spans the pulley 121, can be adjusted.

As shown in FIGS. 7 and 8, the biasing section 112 is arranged in the +Z-axis direction relative to the driving section 111. The biasing section 112 includes a mainspring mechanism 127 , a pulley 128 connected to the mainspring mechanism 127 , and a mounting plate 129 for attaching the mainspring mechanism 127 to the speed increasing section 113 .

As shown in FIG. 10, the mainspring mechanism 127 includes a cylindrical outer cylinder part 130, a first flange 131 attached to the end of the outer cylinder part 130 in the -Z axis direction, and a +Z axis of the outer cylinder part 130. The second flange 132 attached to the axial end is assembled to house and hold various parts inside. Specifically, the mainspring mechanism 127 includes a rotating shaft 133, a first mainspring spring 134, a partition plate 135, and a second mainspring spring 136 as various parts.

The outer cylinder part 130 is arranged so that the direction in which the cavity passes along the Z-axis direction. A plurality of screw holes 130a are formed on the circumference at the end of the outer cylindrical portion 130 on the −Z-axis direction side. These screw holes 130a are for screwing the first flange 131. Similarly, a plurality of screw holes (not shown) are formed on the circumference at the end of the outer cylinder portion 130 on the +Z-axis direction side. These screw holes are for screwing the second flange 132. Furthermore, an L-shaped groove 130c is formed along the entire length of the inner circumferential surface 130b of the outer cylinder portion 130 along the Z-axis direction. This L-shaped groove 130c locks one end of the first mainspring spring 134 and the second mainspring spring 136, as described later.

The first flange 131 is formed into a circular shape as shown in FIG. It is screwed on. A circular opening 131b is formed in the center of the first flange 131, and the first flange 131 has a bearing 138 that rotatably supports the rotating shaft 133 at the location where the opening 131b is formed. .

The second flange 132 is formed in a circular shape, and is screwed to the +Z-axis end of the outer cylindrical portion 130 by passing a screw 139 through a through hole 132a formed on the circumference. A circular opening 132b is formed in the center of the second flange 132, and a bearing 140 that rotatably supports the rotating shaft 133 is housed in the opening 132b.

As shown in FIG. 10, the rotating shaft 133 is a rod-shaped member with a circular cross section, and includes a large diameter portion 133a formed in the center and small diameter portions smaller in diameter than the large diameter portion 133a at both ends of the large diameter portion 133a. 133b and 133c. Furthermore, a groove 133d, which is formed by notching the outer peripheral surface of the large diameter portion 133a, is formed along the longitudinal direction. The rotating shaft 133 passes through the outer cylindrical portion 130, the small diameter portion 133b on the side in the -Z axis direction is fitted in a bearing 138 and rotatably supported, and the small diameter portion 133c on the side in the +Z axis direction is fitted in a bearing 140. It is rotatably supported on the shaft.

As shown in FIGS. 11 and 12, the first mainspring spring 134 is formed by processing a metal strip material into a spiral shape. A first hook portion 134a is formed at the outer end of the first spiral spring 134 by bending. The first hook portion 134a is inserted into the groove 130c of the outer cylinder portion 130 and locked. On the other hand, as shown in FIGS. 11 and 12, a second hook portion 134b is formed at the inner end of the first mainspring spring 134 by bending. The second hook portion 134b comes into contact with the groove 133d of the rotating shaft 133 and is locked therein.

As shown in FIG. 10, the second mainspring spring 136 is arranged on the +Z direction side opposite to the first mainspring spring 134 with the partition plate 135 in between. The second mainspring spring 136 has the same configuration as the first mainspring spring 134, and the first hook portion 136a is inserted and locked into the groove 130c of the outer cylinder portion 130 shown in FIG. 11. On the other hand, the second hook portion 136b abuts and is locked in the groove 133d of the rotating shaft 133.

In this way, the rotating shaft 133 is connected to the outer cylinder part 130 via the first mainspring spring 134 and the second mainspring spring 136 arranged along the Z-axis. As a result, as the rotating shaft 133 is rotated clockwise in the figure from the state shown in FIG. 11 in which the mainspring releases energy, energy is accumulated in the mainspring, and eventually as shown in FIG. The strips of material that make up the mainspring are rolled up and brought together in the center. When the external force acting on the rotating shaft 133 is removed from the state shown in FIG. 12, the mainspring spring gradually releases the accumulated energy while rotating the rotating shaft 133 counterclockwise in the figure. Eventually, the mainspring returns to its energy released state as shown in FIG.

As shown in FIG. 10, the mounting plate 129 is composed of a rectangular plate, and includes an opening 129a through which the rotating shaft 133 is inserted, four through holes 129b arranged around the opening 129a, and a mainspring mechanism 127. Four through holes 129c are formed for mounting. The four through holes 129c are elongated holes, and are formed so that their longitudinal directions face the same direction. The mounting plate 129 is screwed to the first flange 131 by screws 141 passed through the through holes 129b. The mounting plate 129 is larger than the first flange 131, and a portion thereof protrudes to the side of the mainspring mechanism 127, as shown in FIGS. 7 and 8. A through hole 129c is formed in this protruding portion. The mainspring mechanism 127 is screwed to the speed increasing part 113 by a screw 142 inserted into the through hole 129c. Note that by making the through hole 129c into which the screw 142 is inserted an elongated hole, the attachment position of the urging portion 112 to the speed increasing portion 113 can be adjusted. Thereby, the tension of the timing belt 152, which will be described later and spans the pulley 128, can be adjusted. Further, the longitudinal direction of the through hole 129c is aligned with the direction in which the axis of the pulley 128 and the axis of a pulley 151 (FIGS. 13 and 14), which will be described later and is spanned by the timing belt 152, are connected in the XY plane. We are doing so. However, it is optional whether the two directions match. Thereby, the tension of the timing belt 152 can be easily adjusted.

The pulley 128 is connected to the rotating shaft 133 via a mounting member 143, as shown in FIG. The mounting member 143 is fixed to the small diameter portion 133b of the rotating shaft 133 with a screw 144. Pulley 128 is fixed to mounting member 143 by screw 145. As a result, the pulley 128 rotates together with the rotating shaft 133 about the Z-axis.

As shown in FIGS. 5 and 6, the speed increasing section 113 is provided between the driving section 111 and the urging section 112, which are arranged in the Z-axis direction. The speed increasing section 113 transmits the motion output by the drive section 111 to the ball screw shaft 101 shown in FIG. introduce. As shown in FIGS. 7 and 8, the speed increasing section 113 includes a first plate 146, a second plate 147, and a third plate 148 arranged at intervals in the Z-axis direction. A spacing member 149, which is a rod-shaped member, is disposed between the first plate 146 and the second plate 147, so that they are spaced apart from each other in the Z-axis direction. Further, a spacing member 150, which is a rod-shaped member, is disposed between the second plate 147 and the third plate 148, so that they are spaced apart from each other in the Z-axis direction. In this way, various parts of the speed increasing section 113, which will be described below, are attached to the three plates arranged at intervals in the Z-axis direction.

As shown in FIGS. 8 and 13, the first plate 146 has screws 109 inserted thereinto and is screwed to a spacing member 149 fixed to the second plate 147. As shown in FIG. 8, the first plate 146 holds the biasing portion 112 by attaching the mounting plate 129 with the screws 142 from the +Z-axis direction side. Furthermore, a fan-shaped notch 146a is formed in the first plate 146, and this allows the pulley 128 of the biasing section 112 to be placed between the second plate 147 on the −Z-axis direction side. can do. Between the first plate 146 and the second plate 147, as shown in FIG. A belt 152 is arranged. As a result, the rotational motion of the pulley 128 connected to the rotating shaft 133 is increased in speed and transmitted to the pulley 151 via the timing belt 152.

As shown in FIG. 13, the second plate 147 is screwed to a spacing member 150 fixed to the third plate 148 by inserting screws 156 therein. The second plate 147 has a through hole 147a for passing the rotating shaft 154 along the Z-axis direction and accommodating a bearing 162a on the +Z-axis side of the rotating shaft 154, and a through-hole 147a for housing the bearing 162a on the +Z-axis side of the rotating shaft 161. A housing hole 147b for housing the bearing 161a is formed. A pulley 151 is connected by a screw 153 to a rotating shaft 154 passing through the through hole 147a. Thereby, the rotational motion of pulley 151 is transmitted to rotating shaft 154. Furthermore, between the second plate 147 and the third plate 148, as shown in FIG. 158, a timing belt 157 spanned between pulleys 155 and 158, and an idler 159 that contacts and guides the timing belt 157. The rotational motion of a pulley 155 connected to a rotating shaft 154 is increased in speed and transmitted to a pulley 158 via a timing belt 157.

As shown in FIG. 13, the third plate 148 has a spacing member 150 fixed to its surface on the +Z-axis direction side. The third plate 148 has an accommodation hole 148a for accommodating the bearing 162b on the -Z axis direction side of the rotating shaft 154, and an accommodation hole 148b for accommodating the bearing 161b on the -Z axis direction side of the rotating shaft 161. is formed. The rotating shaft 161 passes through a housing hole 148b formed in the third plate 148 and protrudes in the −Z-axis direction. A pulley 164 and a shaft coupling 165 are attached to the portion of the rotating shaft 161 that protrudes in the −Z-axis direction.

The pulley 164 is fixed to the rotating shaft 161 by a screw 119 screwed in from the outer peripheral surface. Further, on the −Z-axis direction side of the third plate 148, as shown in FIG. 16, a timing belt 166 is arranged, which is stretched between the pulley 164 and the pulley 121 of the drive unit 111. The timing belt 166 is arranged in a direction perpendicular to the output shaft 123 of the motor. Note that pulley 121 and pulley 164 of drive unit 111 have the same diameter. Thereby, the rotational motion output by the drive unit 111 is transmitted to the pulley 164 via the timing belt 166.

As shown in FIG. 13, the shaft joint 165 is attached to the rotating shaft 161 by a screw 167 screwed in from the outer peripheral surface. As shown in FIG. 17, this shaft joint 165 is connected to a shaft joint 168 provided at the end of the connection shaft 169 on the +Z-axis direction side. Thereby, the rotational motion of the rotating shaft 161 (FIG. 13) is transmitted to the connecting shaft 169.

As shown in FIG. 17, the connecting shaft 169 is a rotating shaft extending along the Z-axis direction, and has a screw 172 into which the small-diameter portion 101b of the ball screw shaft 101 is screwed from the outer peripheral surface at the end on the −Z-axis direction side. Fixed by

As shown in FIG. 17, the ball screw shaft 101 includes a ball screw shaft main body 101a in which a spiral thread is formed on the outer peripheral surface, and a small diameter portion 101b formed at the end of the ball screw shaft main body 101a on the +Z direction side. It has Further, as shown in FIG. 18, the ball screw shaft 101 further includes a small diameter portion 101c formed at the end on the −Z direction side, and a steady rest member 102 fitted into the small diameter portion 101c. As shown in FIGS. 3 and 18, the ball screw shaft 101 is arranged so that the axis A coincides with the first rod 175 having a hole 175a formed in the center, and at least a portion in the length direction is shaped like a circular tube. The first rod 175 is inserted into the first rod 175 of the first rod 175 . The diameters of the small diameter portions 101b and 101c are smaller than that of the ball screw shaft body 101a. As described above, since the small diameter portion 101b of the ball screw shaft 101 is connected to the connecting shaft 169, the ball screw shaft 101 rotates around the Z-axis as the connecting shaft 169 rotates.

As shown in FIG. 18, the steady rest member 102 includes a ring-shaped steady rest member main body 102a with a groove 102b formed on the outer peripheral surface, and an elastic member 102c accommodated in the groove 102b. The ball screw shaft 101 is inserted into a hole 175a formed in the first rod 175 with the steady rest member body 102a fitted into the small diameter portion 101c. The elastic member 102c is, for example, an O-ring made of fluororubber. Note that the diameter of the elastic member 102c in cross section is larger than the depth of the groove 102b. Therefore, the elastic member 102c protrudes from the outer peripheral surface of the steady rest member main body 102a, and is elastically deformed to contact the inner peripheral surface of the first rod 175. Thereby, the deflection of the first rod 175 that moves in the Z-axis direction can be suppressed.

As shown in FIG. 17, the bearing housing 170 has a through hole 170a along the Z-axis direction, and is fixed to a base 180. A part of the ball screw shaft 101 on the +Z-axis direction side and a part of the connecting shaft 169 connected to the ball screw shaft 101 on the -Z-axis direction side are accommodated in the through hole 170a. On the other hand, the connecting shaft 169 has a portion that protrudes from the end of the bearing housing 170 in the +Z-axis direction. Further, the bearing housing 170 has a bearing 171 in the through hole 170a. The bearing 171 rotatably supports the vicinity of the end of the ball screw shaft 101 on the +Z-axis direction side. Further, a brake 173 is screwed to the end of the bearing housing 170 on the +Z-axis direction side by a screw 174.

The brake 173 is, for example, a non-excitation type brake that applies the brake when power is cut off, and has an opening formed in the center through which the connecting shaft 169 passes. The brake 173 is provided between a disc-shaped plate 173a, a disc-shaped rotor 173b holding the connecting shaft 169, a stator 173c provided with a spring and a coil (not shown), and the rotor 173b and the stator 173c. and a disc-shaped armature 173d. A spring (not shown) provided on the stator 173c applies a force that pushes up the armature 173d in the +Z-axis direction. When the brake 173 is de-energized, the armature 173d pushed up by a spring (not shown) sandwiches the rotor 173b with the plate 173a. Thereby, it is possible to stop the rotation of the connecting shaft 169 or to maintain the stopped state of the connecting shaft 169 in a state where the power supply is cut off. On the other hand, when the brake 173 is energized, a coil (not shown) provided on the stator 173c attracts the armature 173d toward the stator 173c (-Z-axis direction side), and the rotor 173b, which is no longer pinched by the armature, becomes freely rotatable.

As shown in FIG. 2, the ends of a first rod 175, a second rod 176, and a third rod 177 on the +Z-axis direction side are respectively attached to the slide portion 160. The slide portion 160 moves along the Z-axis direction together with these rods 175, 176, and 177. As shown in FIG. 19, the slide section 160 includes a first holding section 186, a second holding section 187 that overlaps the surface of the first holding section 186 in the +X direction, and wiring lines 214 and 216 arranged in the Y-axis direction. (FIG. 2), a second wiring fixture 183 for fixing the wires 215, 217 (FIG. 2) lined up in the Y-axis direction, and a first holding part 186. It includes wiring holding parts 184a, 184b, 185a, and 185b attached to the corners, respectively. Note that the wirings 214, 215, 216, and 217 include power lines and signal lines.

As shown in FIG. 19, the first holding portion 186 is formed with a through hole 186a that extends in the Z-axis direction. A female thread 186b is formed on the inner circumferential surface of the through hole 186a on the −Z-axis direction side. A male thread 175b formed at the end of the first rod 175 in the +Z direction shown in FIG. 3 is screwed into the female thread 186b. Thereby, the first holding part 186 holds the end of the first rod 175 on the +Z direction side. Further, as shown in FIGS. 3 and 17, a ball screw nut 188 is provided on the +Z-axis direction side of the through hole 186a. In this way, the first holding part 186 has a function as a nut holder that holds the ball screw nut 188. As shown in FIG. 17, the ball screw nut 188 is screwed onto the ball screw shaft body 101a, and has a ball screw portion formed on its inner peripheral surface. This ball screw nut 188 is fitted into the ball screw shaft main body 101a via a metal sphere. As a result, the rotational motion of the ball screw shaft 101 is converted into a linear motion of the ball screw nut 188, and the first holding portion 186 that holds the ball screw nut 188 moves linearly. The first rod 175 is directly attached to a first holding portion 186 that holds a ball screw nut 188 with its axis aligned with the ball screw shaft 101 . Therefore, the force converted into linear motion between the ball screw shaft 101 and the ball screw nut 188 is directly transmitted to the first rod 175. For this reason, the first rod 175 functions as a main rod when moving up and down the tip bracket 190 to which the wrist unit 30 and the like shown in FIG. 1 are attached.

As shown in FIG. 19, in the second holding portion 187, through holes 187a and 187c penetrating in the Z-axis direction are formed side by side in the Y-axis direction. Female threads 187b and 187d are formed on the inner circumferential surfaces of the through holes 187a and 187c on the −Z-axis direction side, respectively. As shown in FIG. 20, a male thread 177a formed at the end of the third rod 177 on the +Z direction side is screwed into the female thread 187d. Thereby, the second holding part 187 holds the end of the third rod 177 on the +Z direction side, and the through hole 187c and the through hole 177b formed in the third rod 177 are connected. Similarly, a male thread (not shown) formed at the end of the second rod 176 in the +Z direction shown in FIG. 3 is screwed into the female thread 187b shown in FIG. Thereby, the second holding part 187 holds the end of the second rod 176 on the +Z direction side. Thereby, the through hole 187a formed in the second holding part 187 shown in FIG. 19 and the through hole (not shown) of the second rod 176 are connected. Note that the second holding part 187 is shorter in the Z-axis direction than the first holding part 186 because it does not have a ball screw nut, and the second holding part 187 is shorter in the Z-axis direction than the first holding part 186. It functions as a rod bracket that overlaps the 1 holding part 186. Therefore, the axes of the second rod 176 and the third rod 177 are not aligned with the ball screw shaft 101, and the force converted into linear motion between the ball screw shaft 101 and the ball screw nut 188 is It is indirectly transmitted to the second rod 176 and the third rod 177 via the holding part 187. Therefore, the second rod 176 and the third rod 177 function as auxiliary rods that assist the first rod 175 when moving up and down the tip bracket 190 to which the wrist unit 30 and the like shown in FIG. 1 are attached.

In this way, when the rods 175, 176, 177 held by the first holding part 186 and the second holding part 187 are viewed from the -Z-axis direction, as shown in FIG. The distance from the first rod 175 to the third rod 177 is equal. That is, the rods 175, 176, and 177 are arranged so that their respective centers are located at the apexes of the isosceles triangle. That is, the rods 175, 176, and 177 are arranged so as not to be biased within the housing 50.

As shown in FIG. 22, the first wiring fixture 182 has a first fixing part 182a and a second fixing part 182b arranged in the Y-axis direction, which sandwich the wiring and fix the intermediate part. The first fixing part 182a fixes the middle part of the wiring 216 provided on the +Y side, and the second fixing part 182b fixes the middle part of the wiring 214 provided on the -Y side.

As shown in FIG. 19, the second wiring fixture 183 has a first fixing part 183a and a second fixing part 183b arranged in the Y-axis direction, which sandwich the wiring and fix the intermediate part. The first fixing part 183a fixes the middle part of the wiring 217 provided on the +Y side, and the second fixing part 183b fixes the middle part of the wiring 215 provided on the -Y side.

The wiring holding part 184a is attached to a corner of the first holding part 186 on the -Z-axis direction from the -Y-axis direction via a screw 189, and protrudes from the first holding part 186 in the -Z-axis direction. It has a mounting member 191a extending from the end in the -X-axis direction, and a roller 192a provided at the tip of the mounting member 191a extending in the -X-axis direction. Further, a wiring holding portion 184b is attached to the first holding portion 186 from the −Y-axis direction via a screw 189 at a corner portion on the +Z-axis direction side. The wiring holding part 184b has the same configuration as the wiring holding part 184a, and includes a mounting member 191b and a roller 192b (FIG. 20).

A return 194a is installed between the portion of the attachment member 191a extending in the −X-axis direction and the end surface of the first holding portion 186 in the −Z-axis direction. A return 194b is similarly installed on the end face of the first holding part 186 in the +Z-axis direction. A groove 186c having a curved concave surface is formed along the Z-axis direction on the side surface of the first holding portion 186 facing the −Y-axis direction. Further, in the returns 194a, 194b, openings 194c, 194d communicating with a reversing path (not shown) formed inside the returns 194a, 194b are formed at both ends of the groove 186c. Furthermore, a passage (not shown) extending in the Z-axis direction is formed inside the first holding part 186 and is connected to a reversing path (not shown) of the returns 194a and 194b. These reversal paths (not shown) and passages (not shown) form part of a circulation path for the rolling balls 193. As a result, the ball 193 is placed along the oval track T and rolls on the track T. Further, a scooping portion is formed in the openings 194c and 194d to introduce the ball 193 from the groove 186c to a reversing path (not shown).

As shown in FIG. 19, the roller 192a has a cylindrical shape, and its rotation axis is directed toward the Y-axis. The roller 192a attached to the mounting member 191a partially protrudes from the mounting member 191a in the -Z-axis direction, and also partially projects from the mounting member 191a in the -X-axis direction, as shown in FIG. Similarly, a portion of the roller 192b (FIG. 20) attached to the attachment member 191b protrudes from the attachment member 191b.

The wiring holding part 185a has the same configuration as the wiring holding part 184a, and the only difference is the mounting direction with respect to the first holding part 186, as shown in FIG. That is, the wiring holding portion 185a includes a mounting member 195a and a roller 196a provided on the mounting member 195a. Further, the wiring holding part 185b has the same configuration as the wiring holding part 184b, and the only difference is the mounting direction with respect to the first holding part 186. That is, the wiring holding portion 185b includes a mounting member 195b and a roller (not shown) provided on the mounting member 195a. Further, a return 197a is installed between the part of the mounting member 195a extending in the -X-axis direction and the end face of the first holding part 186 in the -Z-axis direction, and the return part 197a extends in the -X-axis direction of the mounting member 195b. A return (not shown) is installed between the portion and the end face of the first holding portion 186 in the +Z-axis direction. Note that a groove (not shown) similar to the groove 186c on the side surface facing the −Y-axis direction is also provided along the Z-axis direction on the side surface of the first holding portion 186 facing the +Y-axis direction. A reversing path (not shown) formed in the return 197a provided on the axial side and a return (not shown) provided on the +Z-axis direction, and a groove (not shown) on the side surface of the first holding part 186 facing the +Y-axis direction. ) and a passage (not shown) extending in the Z-axis direction formed inside the first holding part 186 form a track that serves as a circulation path for a plurality of rolling balls. As shown in FIG. 2, the slide portion 160 configured in this manner is supported movably in the Z-axis direction by a base body 199 that extends along the Z-axis direction.

As shown in FIG. 22, the base body 199 includes a bottom wall 201 whose longitudinal direction is in the Z-axis direction (direction perpendicular to the drawing), side walls 202 formed on the +Y side and the -Y side of this bottom wall 201, 203. The base body 199 is formed by extruding aluminum, for example.

A protrusion 201a extending in the longitudinal direction (Z direction) is formed at the center in the transverse direction (Y direction) on the bottom wall 201, and a protrusion 201a extends in the Z axis direction on the +Y side and -Y side of the protrusion 201a. Recesses 201b and 201c are formed. The recess 201b is formed over the entire length of the bottom wall 201, and is used as a space for laying the wiring 217 or the wiring 216 (FIG. 2) depending on its position in the Z direction. Further, the recess 201c is formed over the entire length of the bottom wall, and is used as a space for laying the wiring 215 or the wiring 214 depending on the position in the Z-axis direction.

Recesses 202a and 203a are formed in the -Y side surface of the side wall 202 and the +Y side surface of the side wall 203, respectively. Steel rails 206 and 207 formed into substantially rectangular parallelepipeds whose longitudinal direction is in the Z-axis direction are attached to the recesses 202a and 203a. Grooves 206a and 207a are formed in the −Y side surface of the steel rail 206 and the +Y side surface of the steel rail 207 along the Z-axis direction, respectively. The grooves 206a, 207a are formed to face each other, and the inner surfaces of the grooves 206a, 207a are configured as substantially curved surfaces. Specifically, the inner surface of the groove 207a is formed into a curved surface that holds the ball 193 shown in FIG. 19. Similarly, the inner surface of the groove 206a is formed into a curved surface that holds a ball (not shown) provided on the side surface of the first holding portion 186 facing the +Y-axis direction.

As shown in FIG. 19, the base body 199 includes a plurality of balls 193 provided on the −Y-axis direction side of the first holding portion 186 and a plurality of balls (not shown) provided on the +Y-axis direction side. The slide portion 160 is attached via. When the slide part 160 is attached to the base body 199, there is a gap between the groove 207a of the steel rail 207 of the base body 199 shown in FIG. 22 and the groove 186c on the -Y axis direction side of the first holding part 186 shown in FIG. Balls 193 that are continuous in the Z-axis direction are sandwiched between. Similarly, there are balls ( (not shown) is pinched. In this way, by interposing the balls, which are rolling elements connected in the Z-axis direction, between the slide part 160 and the base body 199, the slide part 160 is supported movably in the Z-axis direction by the base body 199. ing.

As shown in FIG. 2, the housing 200 constitutes a part of the base 180 and is attached to the −Z side end of the base body 199. Housing 200 is formed by die casting, for example. Further, as shown in FIG. 18, a through hole 200a for passing the first rod 175 is formed in the housing 200, and a bearing 208b whose axis coincides with the center of the through hole 200a is inserted into the housing 200. It is press-fitted into a flange portion 208a that is integrally installed on the +Z-axis direction side surface. The bearing 208b is, for example, an oilless bearing. Thereby, the first rod 175 is supported movably in the Z-axis direction by the bearing 208b.

Further, as shown in FIG. 2, the housing 200 is formed with a through hole 200b for passing the second rod 176 and a through hole 200c for passing the third rod 177, which are arranged side by side in the Y-axis direction. There is. As shown in FIG. 21, a bearing 210b whose axis coincides with the center of the through hole 200c is press-fitted into a flange portion 210a that is integrally installed on the +Z-axis side surface of the housing 200. Similarly, as shown in FIG. 18, a bearing 209b whose axis coincides with the center of the through hole 200b is press-fitted into a flange portion 209a that is integrally installed on the +Z direction side surface of the housing 200. The bearings 209b and 210b are also oilless bearings, for example. Thereby, the second rod 176 and the third rod 177 are supported movably in the Z-axis direction by bearings 209b and 210b, respectively.

As shown in FIG. 2, the tip bracket 190 is formed from a rectangular plate, and the -Z side ends of each of the rods 175, 176, and 177 are connected to the tip bracket 190. Of these, the first rod 175 and the tip bracket 190 are connected via a screw member 211, as shown in FIG. The screw-in member 211 is a cylindrical member having a flange portion 211a on the −Z-axis direction side, and a thread 211b is formed on the +Z-axis direction side. The screw-in member 211 is inserted through the opening 190a of the counterbore end bracket 190, and is screwed into an internal thread 175c formed on the inner peripheral surface of the first rod 175. Thereby, the first rod 175 and the tip bracket 190 are connected.

As shown in FIG. 21, the third rod 177 is screwed from the outer periphery, with a ring-shaped flange 213 fitted into the -Z-axis direction end. As a result, the flange 213 is fixed to the end of the third rod 177. A screw 218 is screwed into the flange 213 from the -Z axis side of the tip bracket 190 with the end on the -Z axis side in contact with the tip bracket 190. As a result, the tip bracket 190 is attached to the flange 213. Note that, as shown in FIG. 18, the second rod 176 is also fixed to the tip bracket 190 with a flange 212 attached to its end on the −Z-axis direction side.

Furthermore, as shown in FIG. 2, the tip bracket 190 has circular openings 190b and 190c formed at locations where the second rod 176 and the third rod 177 are attached. As shown in FIG. 21, the opening 190c is formed at a position whose center coincides with the through hole 177b of the third rod 177 having a circular tubular shape. Similarly, the opening 190b is formed at a position whose center coincides with the through hole 176a of the second rod 176 (FIG. 22). Thereby, the wiring passed inside the second rod 176 and the third rod 177 can be brought out from the openings 190b and 190c formed in the tip bracket 190.

The actuator 100 includes various types of wiring for operating the motor 120 and brake 173 shown in FIG. 17, as well as wiring for the wrist unit 30 and gripper 40 that are directly or indirectly held by the actuator 100 shown in FIG. provided. The wiring is divided and laid at different locations so that each bundle does not become too thick.

The wirings 214 and 215 shown in FIG. 2 provided on the -Y direction side of the actuator 100 extend from the Y-axis actuator 20 as shown in FIG. It passes through the insertion hole 199a and into the actuator 100. Of the wires 214 and 215 passed through the insertion hole 199a, the wire 214 is laid in the -Z axis direction within the recess 201c (FIG. 22) formed in the base body 199, and then bent 180 degrees. The wire extends in the +Z-axis direction, and as shown in FIG. 20, the intermediate portion is fixed to a first wiring fixture 182 provided on the slide portion 160. The wiring 214 extending from the first wiring fixture 182 is bent 180 degrees again and passed from the through hole 187c of the slide portion 160 to the through hole 177b of the third rod 177. The wiring 214 passed through the through hole 177b of the third rod 177 exits from the opening 190c formed in the tip bracket 190 as shown in FIG. ). In this way, the actuator 100 has a continuous path for passing the wiring from the slide portion 160, through the third rod 177, and through the tip bracket 190.

On the other hand, the wiring 215 is laid in the recess 201c (FIG. 22) formed in the base body 199 in the +Z-axis direction, and then bent 180 degrees and installed in the slide portion 160 as shown in FIG. The intermediate portion is fixed to a second wiring fixture 183. The wiring 215 extending from the second wiring fixture 183 is passed together with the wiring 214 from the through hole 187c of the slide portion 160 to the through hole 177b of the third rod 177, and is formed in the tip bracket 190 as shown in FIG. It exits from the opening 190c and extends to the wrist unit 30 (FIG. 1) attached to the tip bracket 190. Note that a portion of the wiring 215 branches midway and becomes wiring for operating the motor 120 and the brake 173.

Similarly, the wirings 216 and 217 shown in FIG. 2 provided on the +Y direction side of the actuator 100 pass through the insertion hole (not shown) made in the recess 201b (FIG. 22) of the base body 199, and are inserted into the inside of the actuator 100. Passed. As shown in FIG. 2, the wires 216 and 217 pass through the same route as the wires 214 and 215, and as shown in FIG. 3, they are passed through the inside of the second rod 176. The wires 214 and 215 passed through the second rod 176 exit from the tip bracket 190 and extend to the wrist unit 30 (FIG. 1) attached to the tip bracket 190. In this way, the actuator 100 is provided with a continuous path for passing the wiring from the slide portion 160, through the second rod 176, and through the tip bracket 190.

In this way, the second rod 176 and the third rod 177 form a path for passing the wiring for the wrist unit (FIG. 1) provided on the tip bracket 190.

(Operation of Z-axis actuator 100)
Next, the specific operation of the Z-axis actuator 100 will be explained. The actuator 100 shown in FIG. 23 is arranged such that the +Z direction is upward and the -Z axis direction is downward. Although the second rod 176 is not shown in FIGS. 23(a) to 23(c), since it is arranged at the same position on the back side of the third rod 177, it is adjacent to the reference numeral of the third rod 177. The reference numeral 176 for the second rod is given in parentheses at the location where the rod 176 is inserted. Further, in order to understand the internal state of the actuator 100, the cover 181 (FIG. 2) is omitted in FIGS. 23(a) to 23(c).

In the actuator 100 shown in FIG. 23(a), the slide portion 160 is in the uppermost position within the movable range, and the rods 175, 176, and 177 are in the most retracted state. At this time, if power is not supplied to the actuator 100, the brake 173 shown in FIG. 17 is activated, and the rotation of the ball screw shaft 101 can be maintained in a stopped state. Further, as shown in FIG. 11, the mainspring mechanism 127 is in a state in which all energy is released, or in a state in which only a part of the total amount of energy that can be stored by the mainspring mechanism 127 is stored.

When power is supplied to the actuator 100 from the state shown in FIG. 23(a), the brake 173 (FIG. 17) is released. Then, when the output shaft 123 (FIG. 16) of the motor 120 rotates in a direction (first output direction) that moves the slide portion 160 downward, the rotational movement is transmitted via the pulley 121 and timing belt 166 shown in FIG. , to the pulley 164. In this way, the rotational motion transmitted to the pulley 164 is transmitted to the coaxially located ball screw shaft 101, as shown in FIG. 17. As a result, the ball screw shaft 101 rotates in the first rotation direction, and the slide portion 160 supporting the ball screw nut 188 moves downward on the base body 199. As the slide section 160 moves, the rods 175, 176, 177, one end of which is held by the slide section 160, and the tip bracket 190 attached to the other end of the rods 175, 176, 177 move downward, and eventually The state shown in FIG. 23(b) is reached. When the slide portion 160 moves downward in this way, the wiring 214 whose intermediate portion is fixed to the first wiring fixture 182 moves in the −Z-axis direction, as shown in FIGS. 23(a) to 23(b). It is pushed back and laid on the base body 199. On the other hand, the wiring 215 whose intermediate portion is fixed to the second wiring fixture 183 is pulled in the −Z-axis direction, and the wiring laid on the base body 199 rises. Note that the state shown in FIG. 23(b) is a state in which the slide portion 160 is at an intermediate position within the range in which it can move up and down.

In this manner, energy is accumulated in the mainspring mechanism 127 shown in FIG. 7 as the actuator 100 moves the slide portion 160 downward. That is, the rotational motion output from the motor 120 is transmitted to the pulley 128 via the speed increasing section 113. As a result, as shown in FIG. 10, the rotating shaft 133 of the mainspring mechanism 127 to which the pulley 128 is connected rotates, winding up the first mainspring spring 134 and the second mainspring spring 136. As a result, energy is gradually accumulated in the mainspring mechanism 127. The energy accumulated in the mainspring mechanism 127 in this manner acts on the ball screw shaft 101 with an urging force to rotate it in the second rotation direction. This second rotational direction is the rotational direction of the ball screw shaft 101 that moves the slide portion 160 upward.

When the output shaft 123 of the motor 120 is further rotated in the first output direction from the state shown in FIG. 23(b), as shown in FIG. , and the rods 175, 176, and 177 are in a state where they protrude the most from the housing 50. In this way, even when the state changes from FIG. 23(b) to FIG. 23(c), the energy of the mainspring mechanism 127 is accumulated, and when the state of FIG. maximum energy is stored. In this way, the actuator 100 moves the slide portion 160 downward while winding up the mainspring mechanism 127 (while accumulating energy).

From the state shown in FIG. 23(c), when the output shaft 123 (FIG. 16) of the motor 120 rotates in the direction of moving the slide portion 160 upward (second output direction), the ball screw shaft 101 rotates in the second rotation direction. , and the slide portion 160 moves upward on the base body 199. During this time, the ball screw shaft 101 is urged in the second rotation direction by the mainspring mechanism 127. That is, the motor 120 moves the slide portion 160 upward while being assisted by the urging force output by the mainspring mechanism 127. As a result, the rods 175, 176, 177 gradually retract. Eventually, the actuator 100 will be in the state shown in FIG. 23(b), and by further operating the motor 120, the slide portion can be placed in the uppermost position as shown in FIG. 23(c).

When the slide portion 160 moves upward in this way, the wiring 214 whose intermediate portion is fixed to the first wiring fixture 182 moves in the +Z-axis direction, as shown in FIGS. 23(c) to 23(a). The wiring laid on the base body 199 is pulled up. On the other hand, the wiring 215 whose intermediate portion is fixed to the second wiring fixture 183 is pushed back in the +Z-axis direction and laid on the base body 199. Note that the wires 216 and 217 move in the same way as the wires 214 and 215 while the slide portion 160 moves.

Note that, as shown in FIG. 22, various types of wiring are laid in the recesses 201b and 201c of the base body 199 adjacent to the slide section 160, and are pulled or pushed by the movement of the slide section 160 as described above. Moving. At this time, the various wirings laid on the base body 199 are pressed by rollers 192a, 192b, and 196a (the remaining roller is not shown) provided at the corners of the slide portion 160, so that the various wirings are moved. can be kept constant without any variation. In addition, by using rollers 192a, 192b, and 196a (the remaining roller is not shown) as the parts that hold down the various wirings, damage to the wirings 214, 215, 216, and 217 can be prevented, and the sliding part 160 can be moved. can be prevented from being disturbed.

The actuator 100 that operates in this manner can move the slide portion 160 to a desired position by controlling the rotation direction and the number of steps of the output shaft 123 of the motor 120.

(effect)
According to the embodiment described above, the slide portion 160 and the tip bracket 190 are connected by three rods 175, 176, and 177 at intervals. As a result, bending rigidity can be increased and vibrations during operation can be reduced compared to, for example, a case where only one rod 175 is used for connection.

Further, the rods 175, 176, 177 connecting the slide portion 160 and the tip bracket 190 are arranged so that their centers are located at the apexes of the isosceles triangle when viewed from the −Z-axis direction. In this way, by arranging the rods 175, 176, and 177 so that they are not biased within the housing 50, bending rigidity can be increased in any direction orthogonal to the Z-axis (direction of linear motion). . Thereby, vibration during operation can be reduced.

Furthermore, the wiring for the wrist unit 30 attached to the tip bracket 190 can be passed through the hollow portions of the second rod 176 and the third rod 177, and can be brought out from the openings 190b and 190c formed in the tip bracket 190. Leading to 30. Thereby, the wiring of the actuator attached to the tip of the actuator 100 can be easily arranged.

Further, the slide portion 160 is provided with a first wiring fixture 182 and a second wiring fixture 183 that fix the intermediate portion of the wiring passing through the hollow portions of the second rod 176 and the third rod 177. Thereby, the wiring can be moved linearly together with the slide part 160, and the wiring does not interfere with the movement of the slide part 160.

Additionally, rollers 192a, 192b, and 196a (the remaining roller is not shown) are provided at each corner of the slide portion 160. The wiring arranged on the actuator 100 moves and deforms while being pulled or pushed as the slide portion 160 moves. At this time, the wiring laid on the base body 199 is held down by the rollers 192a, 192b, and 196a (the remaining roller is not shown), so that the movement of the wiring can be made constant without variation. Furthermore, by using the rollers 192a, 192b, and 196a (the remaining roller is not shown) as the portions that hold down the wiring, damage to the wiring can be prevented, and movement of the slide portion 160 can be prevented from being obstructed. can.

Further, a non-excitation type brake 173 is provided that brakes the ball screw shaft 101 when the actuator 100 is de-energized. This can prevent the rods 175, 176, 177, etc. from unintentionally moving downward due to gravity when the power to the actuator 100 is turned off or there is a power outage.

Further, a ball, which is a rolling element, is interposed between the slide portion 160 and the base body 199 and extends in the Z-axis direction (the direction of movement of the slide portion 160). This ball is sandwiched between grooves extending in the Z-axis direction, and when the slide portion 160 moves, it rolls along the Z-axis direction, which is the moving direction of the slide portion 160. In this way, the slide portion 160 is capable of linear movement due to the interposition of the rolling elements that are continuous and roll along the direction in which the slide portion 160 can move. Therefore, the slide portion 160 resists a force acting from a direction different from the direction of movement of the slide portion 160, such as torque caused by rotation of a motor, and vibrations are less likely to be transmitted to the rod. This makes it possible to suppress the occurrence of runout at the tip of the work shaft.

This invention is not limited to the embodiments described above, and various modifications and applications are possible. In the above embodiment, in addition to the first rod 175 as one main rod, two rods, the second rod 176 and the third rod 177, are provided as auxiliary rods in the slide portion 160. The number is arbitrary, for example, it may be one, or it may be three or more. Note that the arrangement of the rods is not limited to the arrangement in which the center is located at the apex of the isosceles triangle as described above. For example, if many auxiliary flanges are to be arranged, the auxiliary rods may be arranged on the circumference around the main rod. By arranging the rods without being biased in a predetermined direction in this manner, the bending rigidity in various directions perpendicular to the axis of the rods can be increased. Moreover, three rods may be arranged so that the center is located at the vertex of an equilateral triangle as a special shape of an isosceles triangle. This makes it possible to arrange the rods without bias.

Further, in the above embodiment, wiring is arranged on all of the two auxiliary rods, but it is not necessary to arrange wiring on all of the auxiliary rods, and wiring may be arranged on only some of the auxiliary rods. Moreover, in the above-mentioned wiring route, not only wiring but also piping such as air piping can be similarly installed.

Furthermore, although the rod has been described as having a circular tube shape, the cross-sectional shape of the rod may be arbitrary, and a rod made of a square tube may be employed, or a rod having an elliptical cross-sectional shape may be employed.

Further, although the robot 1 has been described in which the rods 175, 176, 177 of the actuator 100 move in the vertical direction, the actuator 100 can be installed in any direction, and the rods 175, 176, 177 can move horizontally. The actuator 100 may be placed at.

Moreover, although the actuator 100 has been described as having a configuration in which the motor 120 is attached therein, the actuator itself may have a configuration in which the motor is detachable and the actuator itself does not have a motor. In this case, the user may connect the output shaft of the attached motor and the ball screw using a known transmission means.

1: Robot 10: Actuator 11: XY bracket 20: Actuator 21: YZ bracket 30: Wrist unit 30a: Rotating section 40: Gripper 41, 42: Claw section 50: Housing 100: Actuator 101: Ball screw shaft 101a: Ball screw Shaft bodies 101b, 101c: Small diameter portion 102: Steady rest member 102a: Steady rest member body 102b: Groove 102c: Elastic member 110: Drive mechanism 111: Drive portion 112: Urging portion 113: Speed increasing portion 120: Motor 121: Pulley 122: Mounting tool 122a: Flat plate part 122b: Upright part 122c, 211a: Flange part 122e: Long hole 123: Output shaft 127: Mainspring mechanism 128: Pulley 129: Mounting plate 130: Outer cylinder part 130b: Inner peripheral surface 130c: Groove 131: First flange 132: Second flange 133: Rotating shaft 133a: Large diameter portions 133b, 133c: Small diameter portion 133d: Groove 134: First mainspring spring 136: Second mainspring spring 134a, 136a: First hook portion 134b , 136b: Second hook part 135: Partition plate 138, 140: Bearing 143: Mounting member 146: First plate 146a: Notch 147: Second plate 148: Third plate 149, 150: Spacing member 151: Pulley 152 , 157: Timing belt 154: Rotating shaft 155, 158: Pulley 159: Idler 160: Slide portion 161: Rotating shaft 162a, 162b: Bearing 164: Pulley 165, 168: Shaft joint 166: Timing belt 169: Connection shaft 170: Bearing Housing 171: Bearing 173: Brake 175: First rod 175a: Hole 176: Second rod 177: Third rod 180: Base 181: Cover 182: First wiring fixtures 182a, 183a: First fixing parts 182b, 183b: Second fixing part 183: Second wiring fixture 184a, 184b, 185a, 185b: Wiring holding part 186: First holding part 187: Second holding part 188: Ball screw nut 190: Tip bracket 191a, 191b: Mounting member 192a , 192b, 196a: Roller 193: Ball 194a, 194b, 197a: Return 195a, 195b: Mounting member 198: Accommodating part 199: Base body 199a: Insertion hole 200: Housing 201: Bottom wall 201a: Projecting part 201b, 201c: Recessed part 202, 203: Side walls 202a, 203a: Recesses 214, 215, 216, 217: Wiring 206, 207: Steel rails 206a, 207a: Grooves 208a, 209a, 210a: Flange portions 208b, 209b, 210b: Bearing 211: Screwed member 212, 213: Flange

Claims (8)

a ball screw shaft that rotates by transmitting the rotational motion of the output shaft of the motor;
a ball screw nut provided on the ball screw shaft;
a sliding part that has a first holding part to which the ball screw nut is attached and a second holding part that overlaps the first holding part, and that moves linearly in accordance with the rotational movement of the ball screw shaft;
a tubular first rod having one end held by the first holding part;
a tubular second rod having one end held by the second holding part;
a tip bracket that connects the first rod and the second rod at their other ends,
The ball screw shaft passes through the first holding part, and one end is rotatably supported by the inner circumferential surface of the first rod.
actuator. A through hole is formed in the second holding part and connects to a hollow part formed in the second rod,
The tip bracket is formed with an opening that connects to a hollow part formed in the second rod,
A passage is formed for passing wiring from the second holding part, through the second rod, and through the tip bracket;
The actuator according to claim 1. The sliding portion is provided with a wiring fixture for fixing an intermediate portion of the wiring passing through the passage.
The actuator according to claim 2. further comprising a tubular third rod having one end held by the second holding part,
When viewed from the direction in which the slide portion moves linearly, the first rod, the second rod, and the third rod are arranged such that their respective centers are located at vertices of an isosceles triangle.
The actuator according to any one of claims 1 to 3. A through hole connected to a hollow part formed in the third rod is formed in the second holding part,
The tip bracket is formed with an opening that connects to a hollow portion formed in the third rod,
A passage is formed for passing wiring from the second holding part, through the third rod, and through the tip bracket;
The actuator according to claim 4. further comprising a base body that supports the slide portion so as to be capable of linear movement;
A rolling element that is continuous and rolls along the moving direction of the slide part is interposed between the slide part and the base main body.
The actuator according to any one of claims 1 to 5. The one end of the ball screw shaft is provided with a steadying member that comes into contact with the inner circumferential surface of the first rod to suppress swinging of the first rod.
An actuator according to any one of claims 1 to 6. The actuator according to any one of claims 1 to 7, wherein a second actuator is attached to the tip bracket,
The wiring of the second actuator is led from the tip bracket through at least a hollow part of the second rod.
robot.

Images