JP2015150643A - Rotation type gripping unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small-sized and lightweight rotation type gripping device.SOLUTION: A hollow rotary shaft 40 is rotatably arranged on a bearing 30 arranged on a plate 11. A gripping mechanism 60 having two fingers 63A, 63B is mounted on a lower end part of the rotary shaft 40. The rotary shaft 40 is driven and rotated by a motor 21 through pulleys 24, 26 and a belt 25. A solenoid 51 is fixed on the plate 11 in a position of the bearing 30, and driving force of a movable iron core 52 is transmitted to the gripping mechanism 60 through a push rod 53 and a joint member 54 passing in the rotary shaft 40, and the fingers 63A, 63B come close to and separate from each other.

Description

  The present invention relates to a rotary gripping unit (apparatus), and more particularly to a rotary gripping unit that is provided at the tip of a robot and in which a gripping mechanism that grips an object is unitized so as to be rotatable.

Conventional technology

  As gripping devices (or chuck devices) for gripping an object with a pair of claws, fingers, gripping portions, and the like that approach and separate from each other, there are those described in Patent Documents 1 and 2.

JP-A-9-109081 Japanese Patent No. 4337039

  However, all the devices described in these documents achieve only the gripping function, and are not of the type in which the gripping mechanism itself rotates.

  As described above, since the conventional gripping device has only a function of gripping the target object, the gripped target object cannot be rotated. In factory automation, operations such as gripping and lifting an object, rotating it by a predetermined angle, transferring it to a different place, lowering it and releasing it are often required. In this case, a rotation mechanism for rotating the grasped object is required, and a form in which a gripping device including a gripping drive unit is attached to the tip of the rotation shaft of the rotation mechanism is employed.

  In such a configuration, since a separate rotation device and gripping device are provided at the tip of the robot, the weight of the tip becomes heavy and the speed and acceleration of the drive shaft (X, Y, Z axis, etc.) can be increased. There is no problem. Further, along with the length of the tip portion, there are problems that the apparatus becomes large and expensive, and that the cable of the gripping device is twisted by the rotating operation of the rotating shaft.

  The present invention provides a structure that can solve the above-mentioned problems by integrating a rotating shaft and a gripping mechanism.

  The rotary gripping unit according to the present invention includes a support, a bearing device fixed to the support, a rotating body supported rotatably at a predetermined position in the axial direction of the bearing device, and the bearing device of the rotating body. A gripping mechanism including at least two gripping members that are held so as to be able to approach and separate from a portion protruding from the rotation member, a rotation drive unit that is provided on the support body, and that rotates the rotating body, without interfering with the rotation of the rotating body A gripping drive unit provided on the support that includes a shaft that passes through the rotating body, and reciprocates or rotates the shaft, and reciprocating or rotating the shaft of the gripping drive unit of the gripping member of the gripping mechanism. A conversion mechanism for converting the approaching / separating motion is provided. As a result, the at least one gripping member moves, and the object is gripped and released. Further, the gripping operation and the rotation of the rotating body can be controlled independently of each other.

  According to the present invention, the gripping mechanism is provided on the rotating body. The gripping mechanism is also rotated by the rotation of the rotating body. However, the gripping drive unit of the gripping mechanism is not provided on the rotating body. Therefore, it is possible to reduce the size of the rotary gripping unit as a whole and to shorten the length thereof. In this way, it is possible to reduce the size and weight of the rotary gripping unit. As a result, the moving speed and acceleration of the robot arm that supports the rotary gripping unit can be increased. The driving force of the gripping drive unit that drives the gripping mechanism is transmitted to the gripping mechanism through the rotating body without interfering with the rotation of the rotating body. Therefore, not only the rotation drive unit but also the grip drive unit can be provided on the support. As a result, wiring for driving and controlling each drive unit can be fixed to the support, and the risk of disconnection or the like is reduced and reliability is improved.

  In a preferred embodiment, the gripping member further includes biasing means for biasing the gripping member so as to maintain at least one of a gripping position where they are approached and an open position where they are spaced apart.

  In one embodiment, the grip driving unit generates a linear reciprocating motion, and the shaft passes through the center of the rotating body and is reciprocally held. In this case, the conversion mechanism includes a link that converts the reciprocating motion of the shaft into an approaching / separating motion of the gripping member.

  In another embodiment, the grip driving unit generates a rotational motion, and the shaft thereof is rotatably held through the center of the rotating body. In this case, the conversion mechanism includes a gear mechanism that converts the rotation of the shaft into an approaching / separating motion of the gripping member.

  In one embodiment, the gripping member is movably supported on a rail fixed to the rotating body. In another embodiment, the gripping member is provided at the tip of an arm that is swingably provided on the rotating body.

  Both of the at least two gripping members may be held movably, or one of them may be fixed and the other may be held movably.

It is a front view of the whole rotation type grip unit (apparatus). It is a side view of the whole rotary holding unit. It is an expanded sectional view which follows the III-III line of FIG. It is an expanded sectional view which follows the IV-IV line of FIG. FIG. 5 is a cross-sectional view showing a part of FIG. 3 further enlarged (along line VV in FIG. 4). It is an expanded sectional view which follows the VI-VI line of FIG. It is sectional drawing which follows the VII-VII line of FIG. It is a perspective view which shows a part of conversion mechanism and a holding mechanism. This shows the gripping operation by the conversion mechanism and gripping mechanism, and shows the state where the movable part has moved. It shows a modification and is a side view of the entire rotary gripping unit. It shows a modification and is a bottom view of the entire rotary gripping unit. FIG. 12 is a cross-sectional view taken along line XII-XII in FIG. The operation | movement of the conversion mechanism and holding | grip mechanism of a modification is demonstrated. The operation | movement of the conversion mechanism and holding | grip mechanism of a modification is demonstrated. FIG. 12 is a bottom view corresponding to FIG. 11 for explaining operations of a conversion mechanism and a gripping mechanism of a modified example. It is a perspective view which shows the further another modification of a conversion mechanism and a holding mechanism.

  1 and 2 show the appearance of a rotary gripping unit (apparatus). The rotary gripping unit 10 includes a plate (support or frame) 11, and this plate 11 is attached to the tip of the robot. For example, in the case of a 3-axis orthogonal robot, a movable body that moves up and down the Z-axis, in the case of a 1-axis or 2-axis robot, in the horizontal direction of the X-axis or Y-axis, and in the case of a SCARA robot The rotary gripping unit 10 is attached to the tip of the tip arm via the plate 11. Most commonly, the unit 10 is mounted and used in such a manner that the plate 11 is horizontal, so the vertical direction is based on FIGS. 1 and 2 in the following description.

  The upper part of the plate 11 is covered with an upper cover 12, and the lower part is covered with a lower cover 13. A cable outlet 14 is formed in a part of the upper cover 12, and a cable (not shown) including a power line and a signal line for driving and controlling a motor and a solenoid to be described later is drawn out from the cable outlet 14. A gripping mechanism (grip part) 60 projects downward from the opening of the lower cover 13. Fingers (gripping members) 63A and 63B are provided in the gripping portion 60 so as to be movable in the horizontal direction, and these fingers 63A and 63B are driven in directions toward and away from each other, as will be described later. If necessary, grippers (chucks, gripping claws) (shown by chain lines) 73a and 73b suitable for the object to be gripped are attached to the fingers 63A and 63B.

  3 and 4 are enlarged cross-sectional views showing the internal structure of the rotary gripping unit 10.

  A concave portion 11A is formed in the plate 11 at one half of the rotary gripping unit 10 (right half in FIG. 3), and the motor unit (rotary drive unit) 20 is fixed with the rotary shaft 22 facing downward. Has been. The motor unit 20 includes a motor 21 and a rotary encoder 23 that detects the rotation amount or the rotation angle position thereof. A hole is formed in the center of the recess 11A to which the motor unit 20 is attached, and the rotating shaft (output shaft) 22 of the motor 21 projects to the lower side of the plate 11 through this hole. A pulley 24 is fixed to the rotary shaft 22 below the plate 11. Teeth are formed on the pulley 24 and a timing belt 25 is hung thereon.

  In the place of the other half (left half in FIG. 3) of the rotary gripping unit 10, the plate 11 rises in a cylindrical shape, and an embossed part (or boss part, convex part) 11B is formed. A bearing (rotary bearing portion) (bearing device) 30 is arranged and fixed in a cylindrical space inside the lower surface of the embossed portion 11B. The bearing 30 is a ball bearing, and is composed of a ball 31, its retainer, upper and lower bearing holders 32, 33, and the like, and a rotating shaft (rotating body) 40 therein is rotatable and does not move in the axial direction. I support it.

  The rotating shaft 40 has a hollow cylindrical portion (cylindrical portion), the upper end of the cylindrical portion protrudes slightly from the upper surface of the embossed portion 11B of the plate 11, and the lower portion protrudes below the bearing 30. A pulley 26 is fixed to a portion protruding from the lower surface of 11. A timing belt 25 is hung on the pulley 26. Accordingly, the rotary shaft 40 is rotationally driven by the motor 21 via the pulleys 24 and 26 and the timing belt 25.

  The lower part of the rotating shaft 40 protrudes further downward than the position where the pulley 26 is provided, and a space for placing a conversion mechanism and a gripping mechanism (grip part) 60, which will be described later, is formed in this downward projecting part. Thus, two opposing holding walls 41 are integrally formed (see FIG. 3). The gap between the inner surfaces of the holding wall 41 is larger than the inner diameter of the space in the cylinder of the rotating shaft 40. Further, the flange portion 42 passed between the upper ends of the holding walls 41 is integrally provided at a position corresponding to the lower end of the cylindrical portion of the rotating shaft 40 (see FIGS. 4 and 7). Both ends of the holding wall 41 are closed by side covers 61. A disc 27 is fixed between the pulley 26 and the holding wall 41 (upper surface of the flange portion 42) to prevent the abrasion powder and the like from dropping downward from the belt 25.

  A slide bearing 43 is fixedly provided on the inner surface of the lower half of the cylindrical portion of the rotary shaft 40, and a joint member 54 is housed in the slide bearing 43 so as to be movable in the vertical direction. This joint member 54 is indirectly biased upward by the force of a spring 69 described later.

  A gripping drive unit 50 is provided on the embossed part 11B in which the bearing 30 of the plate 11 is housed. That is, the solenoid mounting frame 55 is fixed to the flat surface at the upper end of the embossed portion 11B, and the plunger-type solenoid 51 constituting the gripping drive unit 50 is fixedly mounted in a vertical posture in the mounting frame 55. Yes. A push rod 53 is attached to the lower end of the movable iron core 52 of the solenoid 51, and extends downward in the axial direction in the hollow space of the rotary shaft 40 with a gap between the inner wall and the inner wall. A synthetic resin cap 53 a is attached to the lower end of the push bar 53. The cap 53 a is in contact with the upper end surface of the joint member 54.

  The joint member 54 rotates together with the rotating shaft 40 and the gripping mechanism 60. On the other hand, the solenoid 50 is fixed to the mounting frame 55, and the mounting frame 55 is fixed to the plate 11 (embossed portion 11B). The movable iron core 52 of the solenoid 50 moves in the axial direction. Even if the movable iron core 52 is rotatable, it is preferable not to rotate. The cap 53 a having a smoothly projecting surface contacts the upper end surface of the joint member 54, so that the rotational force is hardly transmitted to the movable iron core 52 even when the joint member 54 rotates.

  The configuration of the conversion mechanism and the gripping mechanism 60 will be described with reference to FIGS.

  Two rails (guides) 62 are fixed in parallel to the lower portions of the two holding walls 41. Fingers 63A and 63B are disposed between the rails 62 and supported so as to be movable along the rails 62 via balls 62a. Further, two pivot pins 66 are fixed between the two holding walls 41 at a position close to the side cover 61 from the center. These pivot pins 66 are above the positions of the fingers 63A and 63B. Links (conversion mechanisms) 65A and 65B are rotatably attached to the pivot pins 66, respectively. Each of the links 65A and 65B has a short arm portion extending inward and downward (in a direction orthogonal to each other) from the position of the pivot pin 66, and U-shaped notches 66a and 66b are respectively provided at the distal ends of the arm portions. Is formed.

  On the other hand, a drive pin 64 passes through and is fixed to the lower end portion of the joint member 54. The drive pin 64 protrudes on both sides of the joint member 54, and is rotatably fitted in the U-shaped notch 66a of the arm portion extending inward of the links 65A and 65B. A driven pin 67 is fixedly inserted into the action parts 63a and 63b extending above the fingers 63A and 63B. These follower pins 67 are rotatable in U-shaped notches 66b formed in the arm portions extending below the links 65A and 65B.

  A recess 68 is formed in one side cover 61, and a spring (biasing member) 69 is accommodated in the recess 68. The spring 69 hits the side surface of the acting portion 63a of the opposing finger 63A at the height position of the driven pin 67, and pushes the finger 63A inward (urging). If necessary, a recess may be formed in the other side cover 61, and a spring (urging member) for pressing the other finger 63B may be housed in the recess.

  When the exciting coil of the solenoid 51 is energized, the iron core 52 descends downward, and the joint member 54 also reaches the lower position (the position shown in FIGS. 3 to 8). At this time, the fingers 63A and 63B are in the most distant state.

  When the energization of the exciting coil of the solenoid 51 is stopped, no magnetic force acts on the iron core 52. Since the spring 69 pushes one finger 63A inward, the finger 63A moves inward along the rail 62. Along with this, as shown in FIG. 9, the link 65A rotates around the pivot pin 66, and the drive pin 64 rises. The urging force of the spring 69 is strong enough to lift the joint member 54 and the movable iron core 52 against the gravity. The upper end of the movable iron core 52 hits the top plate (acting as a stopper) 55a of the mounting frame 55 to determine the upper limit position. A rubber sheet 55b is attached to the lower surface of the top plate 55a to suppress the generation of impact sound when the movable iron core 52 hits the top plate 55a. When the drive pin 64 rises, the other link 65B also rotates about the pivot pin 66, and the finger 63B moves inward. That is, the two fingers 63A and 63B move to a position closest to each other. If there is an object between the two fingers 63A and 63B (or between the claws 73a, 73b, etc. attached thereto), the object is sandwiched (ie, grasped) by the two fingers. The gripping force depends on the strength of the spring 69.

  When the solenoid 51 is energized, the iron core 52 and the joint member 54 are lowered, and the drive pin 64 is lowered. As a result, the links 65A and 65B are rotated about the pivot pin 66 in the opposite direction. Fingers 63A and 63B move away from each other along rail 62. This means releasing the gripped object (canceling release).

  In contrast to the above, when the solenoid 51 is energized, the drive pin 64 may be raised to bring the two fingers 63A and 63B closer. Further, if the position of the drive pin 64 is fixed and the position of the pivot pin 66 is interlocked with the joint member 54, the movement is the reverse of the above.

  Since the above gripping operation and the rotation operation of the rotary shaft 40 are independent of each other and do not affect each other, it is possible to rotate the gripping mechanism 60 while gripping the object, The gripping mechanism 60 can also be rotated.

  As described above, since the conversion mechanism and the gripping mechanism are provided on the rotating shaft (rotating body), the overall size can be reduced. By reducing the size of the rotary gripping unit, the weight can be reduced and the speed and acceleration can be increased. The driving force of the gripping drive unit that drives the gripping mechanism is transmitted to the gripping mechanism through the conversion mechanism in the rotating shaft 40 regardless of the rotation. Therefore, not only the rotation drive unit 20 but also the grip drive unit 50 can be fixed to the plate 11. As a result, the power and control cables for the gripping drive unit can be fixed, the risk of disconnection and the like is reduced, and the reliability is improved.

  Various variations are possible. For example, the gripping drive unit is realized by a motor instead of a solenoid, and the rotational force is transmitted to the gripping mechanism through the rotating shaft (rotating body). The drive mechanism is provided with a mechanism for converting rotation into linear motion of the fingers. Alternatively, the gripping mechanism may be realized by an arm (grip member) whose one end or an intermediate portion is rotatably pivoted instead of a finger moving on the rail, and the arm may be rotated by the above-described rotational force. At this time, the pair of arms may be rotatable, or one arm may be fixed and the other arm may be rotated. Also in the above embodiment, one finger may be fixed and only the other finger may be moved. Furthermore, if necessary, three or more gripping members may be provided.

  Some specific forms of such modifications will be described below. The same reference numerals are given to substantially the same parts as those in the above-described embodiment (those that function in the same manner even if the shapes are slightly different), and a duplicate description is avoided.

  First, referring to FIG. 10 to FIG. 12, the rotating shaft (rotating body) 40 is held by the bearing 30 on the embossed portion 11B of the plate 11 so as to be rotatable and not moved in the axial direction. 40 is rotated through the pulley 24, the belt 25, and the pulley 26 by the motor 21 fixed to the plate 11, as in the case of the above embodiment.

  In this modification, the gripping drive unit, the gripping mechanism, and the conversion mechanism are different from those in the above embodiment. The gripping drive unit is a gripping motor 80, and is fixed on the embossed part 11B. A joint member (rotating shaft) 83 held rotatably at the center of the rotating shaft 40 is coupled (fixed) to the rotating shaft 81 of the motor 80 by a joint 82 at its upper end. Therefore, the joint member 83 is rotationally driven by the motor 80 and is held so as not to fall.

  Two rails 86 are fixed in parallel to each other at the portion of the rotating shaft 40 that protrudes below the bearing 30, and each of these rails 86 has a sliding member (rack member) (moving member) ( Conversion mechanism) 85 is supported slidably (movable). Racks (toothes) 85A are formed on the surfaces of the sliding member 85 facing each other. Fingers 63A and 63B are attached to one end of the two sliding members 85 opposite to each other. On the other hand, a pinion (conversion mechanism) 84 is fixed to the lower end of the joint member 83 and meshes with the racks 85A on both sides. Accordingly, by rotating the motor 80 forward and backward, the pinion 84 rotates through the joint member 83, and the two sliding members 85 having the rack 85A meshing with the pinion 84 move in the opposite directions along the rail 86, and the fingers 63A, 63B. Approach and separate from each other. The sliding member 85 having the rack 85A and the pinion 84 constitute a conversion mechanism. A gripping mechanism is constituted by the sliding member 85 having the rack 85A, the rail 86, the fingers 63A, 63B, and the like.

  With reference to FIGS. 13 to 15, the gripping operation by the fingers 63 </ b> A and 63 </ b> B and the rotation operation of the rotating shaft (rotating body) will be described in a unified manner.

  FIG. 13 shows a state in which the fingers 63A and 63B are separated from each other, that is, in an open state. When the motor 80 is rotated, the fingers 63 </ b> A and 63 </ b> B move in a direction approaching each other by the rotation of the pinion 84. The target portion is gripped directly by the fingers 63A and 63B which are close to each other, or by a gripping tool attached to the fingers 63A and 63B. This is the gripping state shown in FIG. The gripping state is maintained by continuously applying torque to the motor 80 (biasing means).

  When the motor 21 for rotation driving is driven, the rotating shaft (rotating body) 40 rotates via the pulley 24, the belt 25, and the pulley 26. FIG. 15 shows a state in which the rotary shaft 40 is rotated by 90 ° (however, the fingers 63A and 63B are shown in a separated state). When the rotary shaft 40 is rotated, the rack 85A also rotates around the pinion 84 by the same angle. As a result, the sliding member 85 slides in the direction in which the fingers 63A and 63B are separated. In order to prevent such a situation from occurring, the gripping motor 80 is rotated in the opposite direction to the rotation motor 21. As a result, the fingers 63A and 63B are maintained in the gripping state (the closest state).

  However, by adjusting the rotation direction and rotation angle of the gripping motor 80 during the rotation of the rotating shaft (rotating body) 40 by the rotating motor 21, the object can be separated while the rotating shaft (rotating body) rotates. , It can also be controlled to grasp.

  FIG. 16 shows still another modification of the conversion mechanism and the gripping mechanism. The above-described modification is that the conversion mechanism includes a pinion 84 fixed to the lower end of the rotationally driven joint member 83 and a sliding member 85 having a rack 85A meshing with the pinion 84 and guided by the rail 86. Is the same.

  The gripping mechanism includes two arms 91. These arms 91 are pivotally connected by a pivot pin 93 in the vicinity of the middle. The pivot pin 93 is preferably fixed to the lower part (not shown) of the rotating shaft (rotating body) 40. An elongated hole 91A is formed in the upper part of the arm 91, and a drive pin 92 fixed to the end of the sliding member 85 is relatively movable in the elongated hole 91A. The lower ends of the arms 91 are fingers 63A and 63B.

  The pinion 84 is rotated by the rotation of the joint member 83, and the sliding member 85 having the rack 85A slides in the opposite directions along the rail 86. The pin 92 fixed to the sliding member 85 moves the upper end of the arm 91 toward or away from each other, and the fingers 63A and 63B at the lower end of the arm 91 also move toward or away from each other. The arm 91 can be opened and closed by the reciprocating joint member of the above embodiment. In this case, the arm 91 may be opened or held in the holding position by a spring or the like.

10 Rotary gripping unit (Rotary gripping device)
11 Plate (support) (frame)
20 Motor unit (rotary drive)
30 Bearing (Rotating bearing) (Bearing device)
40 Rotating shaft (Rotating body)
50 Grip drive
51 Solenoid
52 Movable iron core
53 Push rod
54,83 Joint member (shaft)
55 Solenoid mounting frame
60 Grip mechanism (gripping part)
62, 86 rails
63A, 63B Finger (gripping member)
65A, 65B link (conversion mechanism)
69 Spring (biasing member) (biasing means)
80 Gripping motor (gripping drive) (biasing means)
84 Pinion (conversion mechanism) (gear mechanism)
85 Sliding member (moving member) (rack member)
85A rack (conversion mechanism) (gear mechanism)
91 Arm (gripping mechanism)

Claims (8)

Support,
A bearing device fixed to the support,
A rotating body rotatably supported by the bearing device at a predetermined position in the axial direction thereof;
A gripping mechanism including at least two gripping members held so as to be able to approach and separate from a portion of the rotating body protruding from the bearing device;
A rotation drive unit provided on the support and configured to rotate the rotating body;
Including a shaft passing through the rotating body without interfering with the rotation of the rotating body, and reciprocating or rotating the shaft, and a reciprocating motion of the shaft of the gripping driving section, A conversion mechanism for converting rotation into an approaching / separating motion of the gripping member of the gripping mechanism;
Rotary gripping unit.   2. The rotary gripping unit according to claim 1, further comprising a biasing unit that biases the gripping member so as to maintain at least one of a gripping position in which they are approached and an open position in which they are separated. The shaft of the gripping drive unit is held so as to freely reciprocate through the center of the rotating body,
The conversion mechanism includes a link for converting the reciprocating motion of the shaft into an approaching / separating motion of the gripping member,
The rotary gripping unit according to claim 1 or 2. The shaft of the gripping drive unit is rotatably held through the center of the rotating body,
The conversion mechanism includes a gear mechanism that converts the rotation of the shaft into an approaching / separating movement of the gripping member,
The rotary gripping unit according to claim 1 or 2.   The rotary gripping unit according to any one of claims 1 to 4, wherein the gripping member is movably supported by a rail fixed to the rotating body.   The rotary gripping unit according to any one of claims 1 to 4, wherein the gripping member is provided at a distal end portion of an arm swingably provided on the rotating body.   The rotary gripping unit according to any one of claims 1 to 6, wherein the at least two gripping members are movably held together.   The rotary gripping unit according to any one of claims 1 to 6, wherein one of the at least two gripping members is fixed and the other is movably held.

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