JP5035216B2 - Electric hand - Google Patents

Description

  The present invention relates to an electric hand configured to open and close a pair of gripping members with a motor to grip a gripping target.

As an electric hand configured to open and close a pair of gripping members by a motor, there is one disclosed in Patent Document 1. This includes a stepping motor, a rotary shaft directly connected to the output shaft of the stepping motor and having a threaded portion at the tip, a linear motion member having a screw screwed into the rotary shaft, and the pair of gripping members. An opening / closing mechanism for performing the operation, and a transmission shaft for transmitting the driving force of the linear motion member to the opening / closing mechanism, the transmission shaft being movable by a certain distance with respect to the linear motion member; When the gripping member grips an object to be gripped by being biased by a spring in the direction in which the gripping operation is performed and assembled to the linear motion member, the gripping object is gripped via the spring.
JP 2001-113486 A

Electric hands are widely used for gripping and transporting various components. In this electric hand, the gripping force disappears at the time of a power failure. However, in the electric hand of Patent Document 1, when the gripping object is gripped by the gripping member, the gripping object is gripped by the spring force of the spring. Therefore, even when a power failure occurs, the gripping force can be maintained.
However, when used by attaching to the tip of a robot arm, a small electric hand is desired. However, in the electric hand of Patent Document 1, the rotating shaft having a screw portion is used as the output shaft of the stepping motor. Since it is directly connected, the length of the electric hand as a whole becomes longer in the axial direction of the rotary shaft, which tends to increase in size.

  Further, in the electric hand of Patent Document 1, the gripping target is gripped when the pair of gripping members move in the closing direction, but depending on the gripping target, for example, in the hole of the gripping target In some cases, it is preferable to grip the object to be gripped by inserting a pair of gripping members and moving them in the opening direction. However, in gripping in the opening direction, the urging force of the spring does not act as gripping force, and in the event of a power failure, the gripping force is lost due to the backs of the screws that are screwed together.

  The present invention has been made in view of the above circumstances, and its purpose is to avoid the increase in size and to grip the object to be gripped by any movement in the closing direction and the opening direction of the pair of gripping members, and at the time of a power failure Another object is to provide an electric hand that does not lose its gripping force.

  In the present invention, since the motor and the rotating shaft are arranged in parallel, the entire electric hand is not long and can be configured in a small size. In addition, the movement of the pair of linear motion members is transmitted to the pair of gripping members, but the object to be gripped is moved by the movement of the pair of gripping members in the closing direction by changing the partner that transmits the movement of each of the pair of linear motion members. The gripping object can be gripped by moving in the opening direction, and the biasing force of the spring member can be applied as the gripping force regardless of which direction is gripped.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings by applying it to an electric hand attached to the tip of a robot arm. The robot referred to in this embodiment is a Cartesian robot, vertical articulated robot, horizontal articulated robot, and a movable body provided on one rail so as to be able to reciprocate. It is assumed that a configuration in which a shaft (arm) is provided so as to be movable in a direction orthogonal to the moving direction of the moving body is also included.

  FIG. 1 shows the entire electric hand. This electric hand uses, for example, a servo motor 1 as an electric drive source, transmits the rotation of the servo motor 1 to a single rotary shaft 2, and the rotational movement of the rotary shaft 2 is converted into a pair of linear motion members 3, 4 by conversion means. Convert to linear motion. That is, when the rotating shaft 2 rotates in one direction, the pair of linear motion members 3 and 4 linearly move in a direction approaching each other, and the rotating shaft 2 rotates in the other direction opposite to the one direction. The pair of linear motion members 3 and 4 are configured to move linearly in directions away from each other, and the pair of linear motion members 3 and 4 are intended to open and close the pair of gripping members. It is.

  The first feature of the electric hand of the present embodiment is that the object to be grasped can be grasped by movement in the closing direction (approach direction) of the pair of grasping members, and also by the movement in the opening direction (separation direction) of the pair of grasping members. The gripping object can be gripped. The second feature is that the spring member that urges the pair of linear motion members 3 and 4 in one of the directions in which the pair of linear motion members 3 and 4 approach each other and the direction in which they are separated from each other, for example, in the direction in which they approach each other. The third feature is that when the pair of linear motion members 3 and 4 move in the direction urged by the spring member, the pair of linear motion members 3 and 4 and the pair of gripping members The pair of gripping members can be moved both in the closing direction and in the opening direction depending on how they are connected to each other. Even when the gripping object is gripped by the movement of the pair of gripping members in the closing direction, the pair of gripping members Even when the object to be grasped is grasped by movement in the opening direction, the spring force of the spring member can be applied as the grasping force.

  As an example of gripping the gripping object by moving the pair of gripping members in the opening direction, for example, a hole is formed in the gripping object, and the pair of gripping members are inserted into the holes and moved in the opening direction. Thus, it is conceivable to hold the pair of gripping members by pressing them against opposite sides of the inner peripheral surface of the hole. In addition, when there are a pair of convex portions on the object to be gripped, various cases are conceivable, such as gripping by inserting a pair of gripping members between the pair of convex portions and moving them in the opening direction.

  The pair of gripping members may be used both when gripping in the closing direction and when gripping in the opening direction, or may be different. In the present embodiment, different gripping members are used in the closing direction and the opening direction, the pair of first gripping members 5 and 6 in FIG. 2 are used in the closing direction gripping, and the pair of second gripping members in FIG. The gripping members 7 and 8 are used for gripping in the opening direction. Note that the second gripping members 7 and 8 used for gripping in the opening direction are different from the first gripping members 5 and 6 used for gripping in the closing direction in that the side surface pressed against the inner peripheral surface of the hole of the gripping object is a hole. Are formed on the arc-shaped side surfaces 7a and 8a in accordance with the arc of the inner peripheral surface.

  As shown in FIG. 4, the servo motor 1 described above includes a rotary encoder (rotation sensor) 10 for detecting the rotational position of the output shaft 9, and is mounted in a rectangular box-shaped main body 11 of an electric hand. It has been. A control unit (not shown) of the servo motor 1 controls the servo motor 1 using the rotational position detection signal output from the rotary encoder 10 as a feedback signal.

  The rotating shaft 2 is disposed in the main body 11 so as to be parallel to the output shaft 9 of the servo motor 1, and both ends thereof are rotatably supported by bearings 12. The rotary shaft 2 and the output shaft 9 of the servomotor 1 both have one end projecting outward from the side surface of the main body 11, and a transmission mechanism such as a belt transmission mechanism is provided between the rotary shaft 2 and one end of the output shaft 9. 13 are connected. That is, toothed pulleys 14 and 15 are attached to one end portions of the rotary shaft 2 and the output shaft 9, respectively. And the toothed belt 16 is spanned between the pulleys 14 and 15 with both teeth. Therefore, when the servo motor 1 is activated, the rotation of the output shaft 9 is transmitted to the rotating shaft 2 by the belt transmission mechanism 13. The belt transmission mechanism 13 is covered with a cover 17 attached to the main body 11.

  The rotary shaft 2 is formed with a right screw 18 and a left screw 19 as conversion means. The right-hand screw 18 and the left-hand screw 19 of the rotary shaft 2 are respectively provided with the linearly-moving members (balls) containing balls (not shown) as screw means that are screwed into the right-hand screw 18 and the left-hand screw 19 inside. Nuts) 3 and 4 are fitted. Therefore, when the rotary shaft 2 rotates, the linear motion members 3 and 4 linearly move in directions opposite to each other.

  The mutually opposing end surface portions of the linear motion members 3 and 4 are formed as large-diameter portions 3a and 4a. Then, compression coil springs 20, 21 as spring members are wound around the linear motion members 3, 4, and the compression coil spring 20 on the linear motion member 3 side has both ends of the large diameter portion 3 a and one of the linear motion members 3, 4. The compression coil spring 21 on the linear motion member 4 side is pressed against the bearing 12, and both ends are pressed against the large diameter portion 4 a and the other bearing 12. The compression coil springs 20 and 21 provided in this manner urge the linear motion members 3 and 4 in the approaching directions that are opposite to each other.

  A guide member 22 is attached to the outer surface of the main body 11 near the linear motion members 3 and 4. The guide member 22 is formed with a guide groove 23 extending in the same direction as the linear motion members 3 and 4 and a pair of sliders 24 and 25 are slidably fitted into the guide groove 23. . The outer surface of the main body 11 and the guide member 22 are formed with elongated openings 26 and 27 that allow communication between the inside of the main body 11 and the guide groove 23.

  The pair of sliders 24 and 25 are coupled to the pair of linear motion members 3 and 4 by the pair of first coupling members 28 and 29 in FIG. 2 or the pair of second coupling members 30 and 31 in FIG. The Specifically, when the first connecting members 28 and 29 are used, as shown in FIG. 4, one linear motion member 3 is connected to one slider 24 by one first connecting member 28, The other linear motion member 4 is coupled to the other slider 25 by the other first coupling member 29. Further, when the second connecting members 30 and 31 are used, as shown in FIG. 5, one linear moving member 3 is connected to the other slider 25 by one second connecting member 30 and the other direct connecting member 3 is connected. The moving member 4 is connected to one slider 24 by the other second connecting member 30.

  Here, specific forms of the first connecting members 28 and 29 and the second connecting members 30 and 31 will be described. Both the first connecting members 28 and 29 have attachment portions 28b and 29b that bend in an arc shape on one end side of the leg portions 28a and 29a, and both the second connecting members 30 and 31 include the leg portions 30a and 29a, Similarly, one end of 31a has connecting portions 30b and 31b that bend in an arc shape. As shown in FIG. 4A, the connecting portion 28 b of one of the first connecting members 28, 29 of the first connecting member 28 is formed of the large-diameter portion 3 a of one linear motion member 3. The connecting portion 29b of the other first connecting member 29 is detachably attached to the end surface of the large-diameter portion 4a of the other linear motion member 4 by the screw 32.

  Further, as shown in FIG. 5A, the connecting portion 30 a of one of the second connecting members 30, 31 of the second connecting member 30 is the same as the large-diameter portion 3 a of one linear motion member 3. The connecting portion 31a of the other second connecting member 30 is detachably attached to the end surface of the large-diameter portion 4a of the other linear motion member 4 by another screw 32.

  As shown in FIG. 4, the other end portions of the leg portions 28 a, 29 a of both the first connecting members 28, 29 in the state of being attached to both the linear motion members 3, 4 are in the opening portion 27 of the guide member 22. In addition, short L-shaped attachment portions 28c and 29c extending in directions away from each other are formed at the other end portions of the leg portions 28a and 29a. The attachment portion 28 c is detachably attached to the slider 24 with a screw 33, and the attachment portion 29 c is detachably attached to the slider 25 with another screw 33.

  On the other hand, as shown in FIG. 5, the other end portions of the leg portions 30 a and 31 a of the second connecting members 30 and 31 are attached to the linear motion members 3 and 4, and the opening portion 27 of the guide member 22. A long L-shaped attachment portion 30c that is located on one side and the other side in the width direction of the opening 27 so as not to interfere with each other and extends in a direction approaching the other end of the leg portion, 31c is extended. The attachment portion 30c is detachably attached to the slider 25 with a screw 33, and the attachment portion 31c is detachably attached to the slider 24 with a screw 33.

  By selectively using the first connecting members 28 and 29 and the second connecting members 30 and 31 as described above, the pair of linear motion members 3 and 4 and the pair of sliders 24 and 25 are connected to each other. Due to the movement of the moving members 3 and 4 in the direction approaching each other, the sliders 24 and 25 are moved in the direction approaching each other (when the first connecting members 28 and 29 are used), or the sliders 24 and 25 are separated from each other. It moves in the direction (when the second connecting members 30, 31 are used).

The first gripping members 5 and 6 or the second gripping members 7 and 8 are selectively attached to the sliders 24 and 25. That is, when the linearly moving members 3 and 4 and the sliders 24 and 25 are connected using the first connecting members 28 and 29, the first holding members 5 and 6 are connected to the sliders 24 and 25 in FIG. When the second connecting members 30 and 31 are used for attachment, the second gripping members 7 and 8 are attached to the sliders 24 and 25 detachably using another screw 34.
In addition, in order to replace the member that connects the linear motion members 3 and 4 and the sliders 24 and 25, the detachable side plate 11a of the main body 11 is removed. Although the side plate 11a is attached to both sides of the main body 11, the side plate on the opposite side is omitted in FIG.

  Next, the operation of the above configuration will be described. First, when using a pair of first gripping members 5 and 6 for gripping a gripping object from the outside, the side plates 11a on both sides of the main body 11 can be removed so that the linear motion members 3 and 4 can be seen from both sides of the main body 11. Keep it. Then, the pair of sliders 24, 25 are removed from the guide member 22, the mounting portion 28 c of one first connecting member 28 is attached to one slider 24 with a screw 33, and the other first connecting member is attached to the other slider 25. 29 attachment portions 29c are attached by screws 33.

  Subsequently, the pair of sliders 24 and 25 are inserted into the guide groove 23 so that the connection portions 28 b and 29 b of both the first connection members 28 and 29 pass through the opening 27 of the guide member 22 and the opening 26 of the main body 11. Fit. Then, the connecting portion 28 b of one first connecting member 28 inserted into the main body 11 is attached to the end surface of the large diameter portion 3 a of one linear motion member 3 with a screw 32, and the other first connecting member 29 is similarly attached. The connecting portion 29 b is attached to the end surface of the large diameter portion 4 a of the other linear motion member 4 with a screw 32. Thereafter, the first holding members 5 and 6 are attached to the sliders 24 and 25 by screws 34. Further, the both side plates 11 a are attached to the main body 11.

  In this state, when the servo motor 1 is started and the output shaft 9 rotates forward and backward, the rotating shaft 2 is rotated in one direction and the other direction. Then, the rotation of the rotary shaft 2 in one direction causes the pair of linear motion members 3 and 4 to move toward each other, and in conjunction with this, the sliders 24 and 25 also move toward each other. At the time of this movement, the linear motion members 3 and 4 are given urging forces in a direction approaching each other by the compression coil springs 20 and 21, so that as shown in FIG. 4 and the right screw 18 and the left screw 19 of the rotating shaft 2 exist on the biasing direction side of the compression coil springs 20 and 21 when viewed from the threads of the right screw 18 and the left screw 19. The screw means of the linear motion members 3 and 4 are balls and not threads, but are shown as threads in FIG. 6 for the sake of clarity (the same applies to FIG. 7 described later).

  When the object to be grasped W1 is grasped between the pair of first grasping members 5 and 6, the sliders 24 and 25 and the linear motion members 3 and 4 stop there. However, the rotary shaft 2 and thus the servo motor 1 rotate slightly after that amount of G, and when the rotation shaft 2 rotates by the amount of G, the servo motor 1 becomes overloaded and stops. Then, since the rotary encoder 10 does not detect rotation, a control unit (not shown) cuts off the servo motor 1.

  In this state, as shown in FIG. 6B, the rattling G between the linear motion members 3, 4 and the left screw 19 and the right screw 18 is viewed from the thread of the right screw 18 and the left screw 19. It exists in the opposite side to the urging | biasing direction of the compression coil springs 20 and 21. FIG. For this reason, even if the servo motor 1 is disconnected, the urging force applied to the linear motion members 3 and 4 from both compression coil springs 20 and 21 is not received by the threads of the right screw 18 and the left screw 19. The pair of first gripping members 5, 6 reach the pair of first gripping members 5, 6, and the pair of first gripping members 5, 6 regulates the rotation of the rotating shaft 2 by the urging force of the compression coil springs 20, 21 and grips the object to be gripped. Continue to hold W1.

Next, when using the pair of second gripping members 7 and 8 that grip the gripping object from the inside, the side plates 11a on both sides of the main body 11 are removed as described above. Then, the connecting portions 5b and 6b of the first holding members 5 and 6 are removed from the linear motion members 3 and 4, the sliders 24 and 25 are removed from the guide member 22, and the first holding members 5 and 6 are moved to the sliders 24 and 25. Remove from.
Thereafter, the mounting portion 31 c of the other second connecting member 30 is attached to one slider 24 with a screw 33, and the attaching portion 30 c of one second connecting member 30 is attached to the other slider 25 with a screw 33. Subsequently, the pair of sliders 24, 25 are inserted into the guide groove 23 so that the connection portions 30 b, 31 b of both the second connection members 30, 31 are passed through the opening 27 of the guide member 22 and the opening 26 of the main body 11. Fit. Next, the connecting portion 30b of one second connecting member 30 inserted into the main body 11 is attached to the end face of the large-diameter portion 3a of one linear motion member 3 with a screw 32, and the other second connecting member 30 is also the same. The connecting portion 31b is attached to the end surface of the large diameter portion 4a of the other linear motion member 4 with a screw 32. Thereafter, the second gripping members 7 and 8 are attached to the sliders 24 and 25 with screws 34. Further, the both side plates 11 a are attached to the main body 11.

In this state, when the servo motor 1 is started and the output shaft 9 rotates forward and backward, the rotary shaft 2 is rotated in one direction and the reverse direction. Then, when the pair of linear motion members 3 and 4 move in a direction approaching each other by rotation in one direction of the rotary shaft 2, the sliders 24 and 25 move in a direction away from each other in conjunction with this, and the second gripping The members 7 and 8 move in the opening direction. During this movement, as described above, as shown in FIG. 7A, the rattling G between the linear motion members 3 and 4 and the right screw 18 and the left screw 19 is the right screw 18 and the left screw 19. Is present on the urging direction side of the compression coil springs 20 and 21.
When the object to be grasped W2 is grasped between the pair of second grasping members 7 and 8, the sliders 24 and 25 and consequently the linear motion members 3 and 4 stop there. However, the rotating shaft 2 (servo motor 1) stops after rotating slightly by the amount of G after that. Then, since the rotation of the rotary encoder 10 is not detected, the control unit (not shown) cuts off the servo motor 1.

  In this state, the rattling G between the linear motion members 3 and 4 and the left screw 19 and the right screw 18 is viewed from the threads of the right screw 18 and the left screw 19 as shown in FIG. It exists in the opposite side to the urging | biasing direction of the compression coil springs 20 and 21. FIG. Therefore, the urging force applied to the linear motion members 3 and 4 from both compression coil springs 20 and 21 is not received by the threads of the right screw 18 and the left screw 19, and the pair of second gripping members 7 and 8 are applied. Therefore, even if the servo motor 1 is disconnected, the pair of second gripping members 7 and 8 continue to grip the gripping target object W2 by restricting the rotation of the rotating shaft 2.

Thus, according to this embodiment, since the rotating shaft 2 is arranged in parallel with the servomotor 1, the main body 11 is different from the case where the rotating shaft 2 is directly connected to the output shaft 9 of the servomotor 1. It is not so long and can be downsized.
In the present embodiment, the object to be grasped can be grasped by either the movement in the closing direction or the movement in the opening direction of the grasping member. In addition, the spring force of the compression coil springs 20 and 21 can be applied as a gripping force regardless of whether the gripping object is gripped by either the closing direction movement or the opening direction movement of the gripping member. Even if the power is cut off, the gripping of the gripping object is not released.

The present invention is not limited to the embodiment described above and shown in the drawings, and can be expanded or changed as follows.
The motor as the drive source may be a stepping motor.
The servo motor 1 to the rotary shaft 9 may be configured to transmit rotation by a gear transmission mechanism.
A compression coil spring is interposed between the pair of linear motion members 3 and 4 to urge the linear motion members 3 and 4 in directions away from each other. The object to be grasped may be grasped by moving in the closing direction or the opening direction.
The sliders 24 and 25 are omitted, and the linear members 3 and 4 are connected to the first holding members 5 and 6 or the second holding members 7 and 8 by the first connecting members 28 and 29 or the second connecting members 30 and 31, respectively. It is good also as a structure connected to.
The spring member is not limited to a compression coil spring, and a tension coil spring may be used. Moreover, it is not restricted to a coil spring.
The use of the electric hand is not limited to that attached to the robot.

The perspective view which shows one Embodiment of this invention and shows it partially disassembled The perspective view which decomposes | disassembles and shows a part different from FIG. Perspective view showing parts used when gripping by moving in the opening direction The case of gripping in the closing direction is shown, (a) is a cross-sectional view, (b) is a cross-sectional view taken along the line Aa of (a). The case of gripping in the opening direction is shown, (a) is a sectional view, (b) is a sectional view taken along the line II in (a). Sectional drawing for demonstrating the effect | action of the urging | biasing force of a compression coil spring in the case of hold | gripping in a closing direction Sectional drawing for demonstrating the effect | action of the urging | biasing force of a compression coil spring in the case of hold | gripping in an opening direction

Explanation of symbols

  In the drawings, 1 is a servo motor, 2 is a rotating shaft, 3 and 4 are linear motion members, 5 and 6 are first gripping members, 7 and 8 are second gripping members, 11 is a main body, and 13 is a belt transmission mechanism. , 18 is a right screw, 19 is a left screw, 20 and 21 are compression coil springs (spring members), 22 is a guide member, 24 and 25 are sliders, 28 and 29 are first gripping members, and 30 and 31 are second screws. The holding member is shown.

Claims (2)

In an electric hand that grips an object to be gripped by converting the rotation of a motor provided in the hand body into an opening / closing operation of a pair of gripping members,
The hand body is rotatably provided so as to be parallel to the output shaft of the motor, and a rotation shaft having a right screw and a left screw formed on the outer periphery,
A transmission mechanism for transmitting rotation of the output shaft of the motor to the rotating shaft;
Screw means for screwing into the right screw and the left screw of the rotating shaft, respectively, and a direction approaching each other with rotation in one direction of the rotating shaft and rotation in the other direction opposite to the one direction; A pair of linear motion members that move away from each other;
A spring member that urges the pair of linear motion members in one of a direction approaching each other and a direction separating from each other;
A coupling means for coupling one and the other of the pair of linear motion members to the pair of gripping members so that the coupling destination can be changed;
The movement of the spring member in the same direction as the biasing direction of the movement of the pair of linear motion members in the approaching direction and the movement of the pair of linear motion members in the direction away from each other is performed by changing the contact address by the connecting means. The pair of gripping members is converted into a movement in the closing direction or a movement in the opening direction to grip the object to be gripped, and either the gripping by the movement in the closing direction or the gripping by the movement in the opening direction of the pair of gripping members is performed. An electric hand characterized in that the pair of gripping members grip the urging force of the spring member on the gripping object. The connecting means is provided between a pair of sliders provided so as to be slidable in a linear direction by a guide member provided on the main body and to which the pair of gripping members are attached, and between the pair of linear motion members and the pair of sliders. A pair of exchangeable first coupling members and a pair of second coupling members for coupling,
The pair of first connecting members are between one linear member of the pair of linear members and one slider of the pair of sliders and between the other linear member and the other slider. The pair of second connecting members connect between the one linear motion member and the other slider and between the other linear motion member and the one slider. The electric hand according to claim 1.

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