JP2013240843A - Finger mechanism for robot hand, and robot hand provided with the finger mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a finger mechanism for a robot hand that has achieved both a high degree of gripping force and a high speed opening and closing of fingers, and to provide a robot hand that can be downsized having this mechanism.SOLUTION: Upon motors 5a, 5b being driven, pinion gears 7a, 7b are brought to rotate in a direction of an arrow A by output shafts 6a, 6b of the motors 5a, 5b, while, further engaging with racks 8a, 8b, move in the horizontal direction (in a direction of an arrow B). In accompanying driving of the motors 5a, 5b, finger parts 4a, 4b fixed on the output shafts 6a, 6b respectively rotate in a direction of approaching a to-be-gripped object O (in a direction of an arrow C). Meanwhile, horizontal movement of pinion gears 7a, 7b with respect to the racks 8a, 8b brings gear boxes 3a, 3b, together with the output shafts 6a, 6b and motors 5a, 5b, to be moved in directions in which they mutually approach each other (in a direction of an arrow D). This brings the finger parts 4a, 4b also to be moved in directions of mutually approaching each other.

Description

  The present invention relates to a finger mechanism for a robot hand and a robot hand equipped with the finger mechanism.

  For example, Patent Document 1 discloses a gripper-type robot hand that grips various gripping objects by controlling the opening and closing of a plurality of finger portions.

JP 2011-240421 A

  In order to reduce the size of a robot hand capable of gripping objects of different sizes, it is necessary to reduce the size of the motor that drives opening and closing of the fingers. Since it decreases, the gripping force of the robot hand becomes small. On the other hand, the gripping force of the robot hand can be increased even if a small motor is used by connecting the fingers to the output shaft of the motor via a reduction mechanism such as a rack and pinion meshing mechanism or a planetary gear mechanism. The opening / closing speed of the finger portion is slowed by the deceleration mechanism, and the work efficiency is lowered. That is, it has been difficult to achieve both increase in gripping force and high-speed opening / closing of the finger portion in a robot hand to be miniaturized.

  The present invention has been made to solve such problems. A finger mechanism for a robot hand that achieves both high gripping force and high-speed opening / closing of a finger portion, and a miniaturizable robot hand including the finger mechanism. The purpose is to provide.

The finger mechanism of the robot hand according to the present invention includes a housing, a movable member provided to be movable with respect to the housing, a motor provided in the movable member, and a pinion gear connected to the output shaft of the motor. And a rack that is fixed to the housing and meshes with the pinion gear, a finger portion that is fixed to the output shaft and rotates by driving the motor, and the pinion gear that moves by meshing with the rack by driving the motor moves the finger together with the movable member. Department moves. When the pinion gear moves while meshing with the rack, the finger part rotates to open and close the finger part, and the movable member moves to give a gripping force to the finger part.
The finger portion may include a parallel link mechanism.
A robot hand according to the present invention includes a plurality of finger mechanisms for the robot hand described above, and when a plurality of finger mechanisms grip a gripping object, the movable member is rotated when the finger portion rotates in a direction approaching the gripping object. Moves in a direction in which the finger portion approaches the grasped object.

  According to this invention, when the pinion gear moves while meshing with the rack, the finger part rotates to open and close the finger part and the movable member moves to give the finger part a gripping force. Both high-speed finger opening and closing can be achieved.

It is a perspective view of the robot hand provided with the finger mechanism which concerns on Embodiment 1 of this invention. It is sectional drawing of the state in which the finger part of the robot hand provided with the finger mechanism which concerns on Embodiment 1 opened. It is sectional drawing of the state in which the finger part of the robot hand provided with the finger mechanism which concerns on Embodiment 1 was closed. FIG. 6 is a configuration diagram in a gear box of a modified example in which a speed reduction mechanism is provided between a motor and a pinion gear in the robot hand including the finger mechanism according to the first embodiment. It is sectional drawing of the state in which the finger part of the robot hand provided with the finger mechanism which concerns on Embodiment 2 opened. It is sectional drawing of the state in which the finger part of the robot hand provided with the finger mechanism which concerns on Embodiment 2 was closed. FIG. 9 is a perspective view of a robot hand provided with a finger mechanism according to a third embodiment.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
Embodiment 1 FIG.
As shown in FIG. 1, the robot hand 1 has a rectangular parallelepiped housing 2. Inside the housing 2, gear boxes 3a and 3b, which are two movable members, are provided so as to be movable by the configuration described later. The gear boxes 3a and 3b are respectively provided with finger portions 4a and 4b so as to be rotatable by a configuration described later.

  As shown in FIG. 2, motors 5a and 5b such as ultrasonic motors and DC motors are provided in the gear boxes 3a and 3b, respectively. Pinion gears 7a and 7b are connected to the output shafts 6a and 6b of the motors 5a and 5b, respectively, and finger portions 4a and 4b are fixed. Further, racks 8a and 8b with which the pinion gears 7a and 7b in the gear boxes 3a and 3b are respectively engaged are fixed to the housing 2. Inside the housing 2, a gap 9 is formed between the gear boxes 3a, 3b.

Next, the operation of the robot hand provided with the finger mechanism according to the first embodiment of the present invention will be described.
As shown in FIG. 2, when the motors 5a and 5b are driven, the pinion gears 7a and 7b are rotated in the direction of arrow A by the output shafts 6a and 6b of the motors 5a and 5b, and further meshed with the racks 8a and 8b. Move in the horizontal direction (direction of arrow B). As the motors 5a and 5b are driven, the finger portions 4a and 4b fixed to the output shafts 6a and 6b rotate in the direction approaching the grasped object O (the direction of the arrow C), respectively. On the other hand, by the horizontal movement of the pinion gears 7a and 7b with respect to the racks 8a and 8b, the gear boxes 3a and 3b move together with the output shafts 6a and 6b and the motors 5a and 5b in the direction approaching each other (direction of arrow D). Thereby, the finger parts 4a and 4b move in a direction in which the finger parts 4a and 4b approach each other, that is, in a direction in which the finger parts 4a and 4b approach the grasped object O.

  As a result, as shown in FIG. 3, the gripping operation of the robot hand 1 that grips the gripping object O between the finger portions 4a and 4b is performed. Specifically, the finger portions 4a and 4b each perform a closing operation (an operation that rotates in a direction approaching the object to be grasped O), and the gear boxes 3a and 3b move in a direction to reduce the gap 9 to move the finger portions. The distance between 4a and 4b becomes small. Thereby, the gearboxes 3a and 3b (finger portions 4a and 4b) are driven by the force in the rotation direction when the finger portions 4a and 4b are rotated in the direction approaching the grasped object O and the motors 5a and 5b are driven. A horizontal force by moving in a direction approaching each other is applied.

  By rotating the motors 5a and 5b in the reverse direction, that is, by rotating the pinion gears 7a and 7b in the direction opposite to the arrow A, the fingers 4a and 4b are opened (turned away from the object to be grasped O). Operation). Further, the gearboxes 3a and 3b move away from each other (the direction opposite to the arrow D) by the horizontal movement (the direction opposite to the arrow B) accompanying the rotation of the pinion gears 7a and 7b. The distance between the parts 4a and 4b is increased. As a result, the fingers 4a and 4b return to the non-gripping state as shown in FIG.

  In other words, the outputs of the motors 5a and 5b are transmitted to the fingers 4a and 4b that perform the opening and closing operations via the output shafts 6a and 6b, and the pinion gears 7a and 7b are connected to the racks 8a and 8b by the outputs of the motors 5a and 5b. The force resulting from the movement of 7b in the horizontal direction is transmitted.

  In the above configuration, for example, when a small ultrasonic motor (torque: 3.0 kgf · cm, rotation speed: 100 rpm) is used as the motors 5a, 5b, and the pinion gears 7a, 7b are 10 mm in diameter, The opening / closing speed of 4b is 100 rpm, and the gripping force by the fingers 4a, 4b is about 60N. That is, even when a small ultrasonic motor is used, the gripping force of the robot hand 1 can be increased without providing a reduction mechanism having a large reduction ratio. Further, since the robot hand 1 is not provided with a speed reduction mechanism having a large speed reduction ratio, the opening / closing speed of the finger portions 4a and 4b is not increased.

  Thus, when the pinion gears 7a and 7b move while meshing with the racks 8a and 8b, the finger portions 4a and 4b rotate to open and close the finger portions 4a and 4b, and the gear boxes 3a and 3b move. Since a gripping force is applied to the finger portions 4a and 4b, both a high gripping force and high-speed opening and closing of the finger portions 4a and 4b can be achieved.

  In the first embodiment, the two gear boxes 3a and 3b are provided in the housing 2. However, the present invention is not limited to this configuration. One gear box is provided in the housing 2 (therefore, one finger portion) and a fixing member such as a plate is provided so as to face the one finger portion. A form in which the object to be grasped is grasped by the fixing member may be employed. In this case, the shape of the fixing member is not limited to a plate shape, and may be any shape and size.

  In the first embodiment, the finger portions 4a and 4b are respectively fixed to the pinion gears 7a and 7b connected to the output shafts 6a and 6b of the motors 5a and 5b. However, the present invention is not limited to this configuration. As shown in FIG. 4, the output of the motor 5 a may be transmitted to the pinion gear 7 a via the reduction gears 31 and 32 that are reduction mechanisms. In this case, the reduction gear 32 and the pinion gear 7 a share the rotation shaft 33, and the finger portion 4 a is fixed to the rotation shaft 33. Here, the rotation shaft 33 transmits the rotation of the output shaft 6a to the pinion gear 7a via the reduction gears 31 and 32, and thus constitutes the output shaft of the motor 5a. Although not shown in the drawing, the same configuration is applied to the case where there is a speed reduction mechanism in the middle of power transmission from the motor 5b to the pinion gear 7b.

Embodiment 2. FIG.
Next, a robot hand provided with a finger mechanism according to Embodiment 2 of the present invention will be described. In the following embodiments, the same reference numerals as those in FIGS. 1 to 4 are the same or similar components, and thus detailed description thereof is omitted.
The robot hand according to Embodiment 2 of the present invention is configured such that the fingers 4a and 4b have parallel links with respect to Embodiment 1.

  As shown in FIG. 5, the finger portion 4a of the robot hand 10 includes two parallel links 4a1 and 4a2 and a gripping claw 15a that is rotatably connected to the respective tip portions of the parallel links 4a1 and 4a2. Have. Here, the parallel links 4a1 and 4a2 and the gripping claws 15a constitute a parallel link mechanism. One end of one parallel link 4a1 of the two parallel links 4a1 and 4a2 is fixed to the output shaft 6a of the motor 5a. One end of the other parallel link 4a2 is provided with a rotating shaft 17a serving as a rotation center of the parallel link 4a2. The rotating shaft 17a moves in the direction in which the gear box 3a moves, that is, in the horizontal direction (the direction of arrow E). It is possible. The other finger 4b of the robot hand 10 also has a parallel link mechanism composed of two parallel links 4b1 and 4b2 and a grip claw 15b having the same configuration as described above. Other configurations are the same as those of the first embodiment.

Next, the operation of the robot hand provided with the finger mechanism according to Embodiment 2 of the present invention will be described.
As shown in FIG. 5, when the motor 5a is driven, the parallel link 4a1 fixed to the output shaft 6a rotates in a direction approaching the grasped object O (direction of arrow C). As the parallel link 4a1 rotates, the gripping claws 15a connected to the parallel link 4a1 also rotate in the direction approaching the object to be gripped O (the direction of the arrow C ′). Further, along with the rotation of the gripping claw 15a, the parallel link 4a2 connected to the gripping claw 15a also rotates in the direction approaching the gripping object O (the direction of the arrow C ") around the rotation shaft 17a. As the parallel link 4a2 rotates, the shaft 17a moves in the horizontal direction in the direction approaching the rotation shaft 17b of the finger portion 4b (the direction of the arrow E. The same applies to the rotation of the finger portion 4b. As shown in FIG. 6, the fingers 4a and 4b can be closed while the two gripping claws 15a and 15b are in parallel so that the gripping object O can be gripped between the parallel gripping claws 15a and 15b. Note that the gripping force by the finger portions 4a and 4b is given by the same operation as that described in the first embodiment.

  Also in the second embodiment, when the pinion gears 7a and 7b move while meshing with the racks 8a and 8b, the finger portions 4a and 4b rotate to open and close the finger portions 4a and 4b, and the gear boxes 3a and 3b Since it moves and gives a gripping force to the finger parts 4a and 4b, the same effect as the first embodiment can be obtained. In the second embodiment, when the finger portions 4a and 4b are rotated, the gripping claws 15a and 15b of the finger portions 4a and 4b are maintained in a parallel state, so that the gripping object O and the gripping claws 15a and 15b Since the contact area with 15b becomes large, stable gripping becomes possible.

  Also in the second embodiment, a modification of the first embodiment, that is, a modification in which one gear box is provided in the housing 2 and a fixing member such as a plate is provided so as to face the finger portion, or a deceleration A modification in which a mechanism is provided is also applicable.

Embodiment 3 FIG.
Next, a robot hand provided with a finger mechanism according to Embodiment 3 of the present invention will be described.
The robot hand according to Embodiment 3 of the present invention is obtained by changing the arrangement form of a plurality of gear boxes with respect to Embodiment 1.

  As shown in FIG. 7, the robot hand 20 has three housings 22 each provided with one gear box 23, and each housing 22 is arranged in parallel with the longitudinal direction of the housing 22. ing. Of the three housings 22, the finger portion 24 extending from the gear box 23 in the housing 22 arranged in the middle is opposite to the two finger portions 24 extending from the gear box 23 in the other housing 22. Is provided. In each housing 22, a gap 29 is formed between the gear box 23 and the wall portion 22 a of the housing 22 provided on the side opposite to the finger portion 24. As 23 moves, the gap 29 becomes larger or smaller. Other configurations, in particular, the configuration in the gear box 23 are the same as those in the first embodiment.

  By the same operation as in the first embodiment, each finger unit 24 rotates and each gear box 23 moves in the housing 22 so that each gap 29 becomes small. The object can be gripped. When releasing the object to be grasped, an operation opposite to this operation may be performed.

  Also in the third embodiment, the pinion gears 7a and 7b move while meshing with the racks 8a and 8b, so that each finger 24 rotates and each finger 24 opens and closes, and the gear box 23 moves to move the finger. Since the gripping force is applied to the portion 24, the same effect as in the first embodiment can be obtained. Further, in the third embodiment, each finger portion 24 grips the gripping object at three positions that are positioned non-linearly, so that stable gripping is possible.

  In the third embodiment, the number of finger portions 24 is three. However, the present invention is not limited to the form of three finger portions. It may be in the form of two fingers or in the form of four or more fingers.

  In the first to third embodiments, when a plurality of gearboxes and finger portions are provided, it is not necessary that all gearboxes and finger portions operate in the same manner. For example, in the first and second embodiments, when the gear box 3a does not move in the horizontal direction and the finger portion 4a does not rotate, the gear box 3b moves in the horizontal direction and the finger portion 4b rotates, The movement distances of the boxes 3a and 3b and the rotation angles of the finger portions 4a and 4b may be different. For example, also in the third embodiment, the movement distances of the three gear boxes 23 and the rotation angles of the three finger portions 24 may be operated differently.

  1,10,20 Robot hand, 2,22 Case, 3a, 3b, 23 Gear box (movable member), 4a, 4b, 24 Finger part, 4a1, 4a2, 4b1, 4b2 Parallel link (parallel link mechanism), 5a , 5b Motor, 6a, 6b Output shaft, 7a, 7b Pinion gear, 8a, 8b Rack, 15a, 15b Holding claws (parallel link mechanism), 33 Rotating shaft (output shaft), O Holding object.

Claims (3)

A housing,
A movable member provided movably with respect to the housing;
A motor provided in the movable member;
A pinion gear connected to the output shaft of the motor;
A rack fixed to the housing and meshed with the pinion gear;
A finger portion fixed to the output shaft and rotated by driving of the motor;
A finger mechanism for a robot hand in which the finger portion moves together with the movable member when the pinion gear moves while meshing with the rack by driving of the motor.   The finger mechanism for a robot hand according to claim 1, wherein the finger portion includes a parallel link mechanism. A plurality of finger mechanisms for the robot hand according to claim 1 or 2,
When gripping an object to be grasped by the plurality of finger mechanisms, when the finger part rotates in a direction approaching the object to be grasped, the movable member moves in a direction in which the finger part approaches the object to be grasped. Robot hand.

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