JP2010023194A - Stopper device for robot - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent not only shearing of a stopper bolt but also damage of a partner member side fixed with the stopper bolt in a stopper device for suppressing movement of an arm exceeding a set range by colliding the arm to the stopper bolt. <P>SOLUTION: On the partner member 11 fixed with the stopper bolt 12, a narrow groove 15 extending from a penetration hole of the stopper bolt 12 in a collision direction of the arm is formed, and the stopper bolt 12 intrudes from the penetration hole into the groove 15 while deforming both side parts of the groove 15 when the stopper bolt 12 collides to the arm and is deformed exceeding a predetermined amount. Therefore, shearing of the stopper bolt 12 and damage of the partner member 11 side thread-attached with the stopper bolt 12 can be prevented. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a stopper device for a robot that prevents movement of an arm beyond a movable range.

For example, in an articulated robot, a plurality of arms are connected by a joint structure, and each arm rotates (turns) around the joint. Each arm has a pre-set movable range. Normally, it is controlled to rotate within the movable range by controlling the rotational speed of the motor that is the drive source, but for some reason the arm exceeds the movable range. In order to prevent the rotation mechanically, a stopper device is provided (for example, Patent Document 1).
JP 2007-50499 A

  In the stopper device of the above-mentioned Patent Document 1, a stopper bolt is fixed to one arm among one arm and the other arm rotatably supported by this arm, and an impact member is attached to the other arm. When the other arm is fixed by a bolt and the other arm exceeds the movable range, the abutting member collides with the stopper bolt to restrict the other arm from rotating further.

  In the stopper device of Patent Document 1, when the arm rotates beyond the movable range, the abutting member collides with the head of the stopper bolt. At the time of the collision, a large impact force acts on the abutting member and the stopper bolt. In this case, in order to prevent the fixing bolt of the impacting member from being sheared by the impact force, the inner diameter of the through hole of the fixing bolt formed in the impacting member is partially enlarged to When a large impact force acts on the member, the fixing bolt is bent at the inner diameter enlarged portion of the through hole to absorb the impact force.

  Although the impact absorbing structure of Patent Document 1 is effective in preventing shearing of the fixing bolt of the impact member, the counterpart stopper bolt that receives the impact member is directly screwed to the arm. The impact force acting on the stopper bolt is finally received by the screw hole portion of the arm to which the screw portion of the stopper bolt is screwed, so that an unreasonable force acts on the screw hole portion and the screw hole There is a risk of damage to the surrounding area.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a robot stopper capable of preventing not only the stopper bolt from being sheared but also damage to the counterpart member to which the stopper bolt is fixed. To provide an apparatus.

  According to the first aspect of the present invention, a narrow groove extending in the collision direction of the arm from the through hole of the stopper bolt is formed in the mating member for fixing the stopper bolt, and the stopper bolt is collided with the arm. When the deformation exceeds the fixed amount, both sides of the groove are deformed and penetrated from the through hole into the groove. Therefore, the impact force applied to the stopper bolt is affected by the deformation of the stopper bolt itself and the stopper bolt. It is absorbed by the deformation of both sides of the groove accompanying the deformation, and shearing of the stopper bolt is prevented. At the same time, with respect to the mating member to which the stopper bolt is fixed, the screw hole into which the stopper bolt is screwed and its peripheral portion are prevented from being damaged.

  In the invention of claim 2, since the depth of the groove is equal to or larger than the diameter of the stopper bolt, when the stopper bolt receives an impact force, the stopper bolt is easily deformed, and thus acts on the stopper bolt. The impact force is easily absorbed by the deformation of both side portions of the groove, and as a result, shearing of the stopper bolt and damage to the threaded hole of the mating member and its periphery can be effectively prevented.

In the third aspect of the invention, the length of the groove from the open end to the front end of the groove in the through hole is approximately ½ or more of the width of the groove. Therefore, the length of the groove corresponding to the amount of deformation of the stopper bolt Can be secured.
In the invention of claim 4, since the width W of the groove is 0.7 times or more the shaft diameter d of the stopper bolt and less than the diameter d, when the stopper bolt is deformed, it easily enters the groove from the through hole. Become.

  In the invention of claim 5, since the width of the groove becomes narrower as it goes away from the through hole, the deformation amount of both sides of the groove acting to prevent the deformation gradually increases as the deformation amount of the stopper bolt increases. Therefore, it is possible to more effectively prevent shearing of the stopper bolt and damage to the threaded hole of the counterpart member and its peripheral portion.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. For example, in a 6-axis vertical articulated robot, as shown in FIG. 4, first to sixth links 2 to 7 are sequentially connected to a base 1 via joints. Specifically, the first link 2 is provided on the base 1 so as to be rotatable (turnable) by a first joint having a rotation axis J1, and the second link 3 is provided on the first link 2 and has a rotation axis J2. The second link 3 is provided to be able to rotate (turn), and the third link 4 is provided to the second link 3 to be rotatable (turned) by the third joint having the rotation axis J3. The link 5 is provided to be rotatable (turned) by a fourth joint having a rotation axis J4, and the fifth link 6 is provided to the fourth link 5 to be rotatable by a fifth joint having a rotation axis J5. The sixth link 7 is rotatably provided on the fifth link 6 by a sixth joint having a rotation axis J6.

  Among the first to sixth links 2 to 7, for example, a stopper mechanism 8 for regulating the rotation range of the third link 4 is provided between the second link 3 and the third link 4. Is provided. The stopper mechanism 8 includes a stopper block 10 attached to the outer shell 9 of the third link 4 and a stopper bolt 12 provided on the outer shell 11 of the second link 3. When the third link 4 attempts to rotate (overrun) over a predetermined angular range, for example, approximately one rotation, with respect to the second link 3, the stopper mechanism 10 is configured so that the stopper block 10 is stopped with a stopper bolt. 12 is configured to prevent overrun of the third link 4 by colliding with 12.

  The outer shell 11 of the second link 3 which is a mating member for fixing the stopper bolt 12 is made of, for example, aluminum, and a through hole 13 of the stopper bolt 12 is formed at a predetermined position as shown in FIGS. Has been. The through hole 13 is for passing the stopper bolt 12 and is formed in a circular shape that is slightly larger than the diameter d of the shaft portion 12 a of the stopper bolt 12. A screw hole 14 for screwing the screw portion 12 b of the stopper bolt 12 is formed at the bottom of the through hole 13. In addition, the diameter D of the through hole 13 may be equal to the diameter d of the shaft portion 12a of the stopper bolt 12. In short, the diameter D may be equal to or larger than the diameter d of the shaft portion 12a.

  Furthermore, a groove 15 extending in the collision direction of the stopper block 10 from the through hole 13 to the stopper bolt 12 is formed in the outer shell 11 of the second link 3. In this embodiment, since the rotation of the third link 4 exceeding one rotation is stopped by one stopper bolt 12, the stopper block 10 collides with the stopper bolt 12 from the clockwise direction, Or it collides from a counterclockwise direction. For this reason, two grooves 15 are formed so as to extend in opposite directions from the through holes 13.

  Here, the depth, width, and length of the groove 15 will be described. First, the depth of the groove 15 indicated by H in FIG. 1A is equal to or greater than the diameter d of the stopper bolt 12, and in this embodiment, the depth is equal to the depth of the through hole 13 that is equal to or larger than the diameter d of the stopper bolt 12. Has been. The width of the groove 15 indicated by W in FIG. 3 is not less than 0.7 times the diameter of the shaft portion 12a of the stopper bolt 12 indicated by d in FIG. 2, and does not exceed the diameter d (0.7d ≦ W < d). Further, the distance from the center of the through hole 13 indicated by L in FIG. 3 to the tip of the groove 15 is determined to satisfy the following equation (1).

L> W / 2 + [(d / 2) ² − (W / 2) ² ] ^1/2 (1)
Next, the operation of the above configuration will be described. When the third link 4 overruns for some reason, the stopper block 10 collides with the head 12c of the stopper bolt 12 as shown in FIG. At this time, depending on the impact force, a portion of the shaft portion 12a of the stopper bolt 12 located in the through hole 13 is bent and deformed as shown in FIG. 1 (b), and when the deformation exceeds a predetermined amount, The shaft portion 12 a enters the groove 15.

  When the shaft portion 12 a enters the groove 15, the shaft portion 12 a deforms both side portions of the groove 15. Since considerable energy is required for the deformation of both sides of the groove 15, the impact applied to the stopper bolt 12 due to the collision of the stopper block 10 is mitigated, and excessive deformation of the shaft portion 12a is suppressed. As a result, shearing of the stopper bolt 12 is prevented, and the screw hole 14 to which the screw portion 12b is screwed is prevented from being damaged, and the periphery of the screw hole 14 is prevented from being damaged.

  In this case, since the diameter D of the through hole 13 is slightly larger than the diameter d of the shaft portion 12a of the stopper bolt 12, the shaft portion 12a is initially deformed, so that the impact at the time of collision of the stopper block 10 is absorbed. Then, the shaft portion 12a is deformed with deformation of both side portions of the groove 15. As a result, the impact at the time of collision of the stopper block 10 is absorbed, so that the diameter D of the through hole 13 is equal to the diameter d of the shaft portion 12a, and the deformation of the shaft portion 12a immediately deforms both sides of the groove 15. Compared with the case where the shock absorption is accompanied, the tendency that the shock absorbing power gradually increases is obtained, and the shock is effectively mitigated.

  Further, since the depth H of the groove 15 is equal to or greater than the diameter d of the stopper bolt 12, the minimum length of the shaft portion 12a of the stopper bolt 12 from the bottom of the through hole 13 that is easily bent and deformed. The above can be ensured. For this reason, it can prevent more effectively that the bolt 12 for stoppers is damaged by the impact at the time of the collision of the above-mentioned stopper block 10, and the circumference of screw hole 14 and screw hole 14 is damaged.

  Furthermore, the width W of the groove 15 is set to be 0.7 times or more and less than d of the diameter d of the shaft portion 12a of the stopper bolt 12. When the opening width of the groove 15 into the through hole 13 is expressed by an arc angle with the center O of the through hole 13 as the center, it is approximately 90 ° or more and less than 180 °. The minimum arc angle of 90 ° is the minimum angle at which the shaft portion 12a of the stopper bolt 12 is likely to enter the groove 15 when the shaft portion 12a of the stopper bolt 12 is deformed. However, it is possible to enter the groove 15 relatively easily while deforming both side portions of the groove 15.

In addition, the distance L from the center O of the through hole 13 to the tip of the groove 15 is determined as in the equation (1). In this equation (1), the square root of (d / 2) ² − (W / 2) ² is substantially equal to the distance t from the center O of the through hole 13 to the open end of the groove 15 into the through hole 13. The expression (1) means that the length s from the opening end of the groove 15 to the through hole 13 to the tip of the groove 15 is W / 2 or more. If s is equal to or greater than W / 2, the length range in which the side portion of the groove 14 can be deformed in accordance with the bending deformation of the shaft portion 12a of the stopper bolt 12 is approximately the length corresponding to W / 2. If there is such a bending deformation, the impact of the stopper block 10 can be sufficiently absorbed.

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 groove 15 may be tapered as shown in FIG. In this case, the width W of the groove 15 is represented by the opening width into the through hole 13.
The through hole 13 is not limited to a circle, and may be a quadrangle or a polygon.
The head portion 12c of the stopper bolt 12 is not limited to a diameter larger than that of the shaft portion 12a, and may be equal in diameter to the shaft portion 12a or smaller than the shaft portion 12a.

  In the present invention, the screw hole into which the threaded portion of the stopper bolt is screwed is formed with a thread groove so as to surround the entire circumference of the threaded portion of the stopper bolt, and the thread of the threaded portion of the stopper bolt This refers to the part that is locked. Therefore, the screw portion 12b of the stopper bolt 12 is formed in the entire vertical direction of the shaft portion 12a, and a thread groove that is screwed to the screw portion 12b of the stopper bolt 12 is formed on the inner periphery of the through hole 13. However, since this thread groove does not surround the entire circumference of the thread of the threaded portion, it is excluded from the screw hole of the present invention.

The main part in one Embodiment of this invention is shown, (a) is sectional drawing at the time of normal, (b) is sectional drawing when the bolt for stoppers deform | transforms by the collision of a stopper block. Sectional drawing which follows the II-II line of Fig.1 (a) Top view of through holes, screw holes and grooves Robot perspective view FIG. 2 equivalent view showing another embodiment of the present invention

Explanation of symbols

  In the drawings, 1 is a base, 2 to 7 are first to sixth links, 8 is a stopper mechanism, 10 is a stopper block, 11 is an outer shell (a mating member), 12 is a stopper bolt, 13 is a through hole, 14 Indicates a screw hole, and 15 indicates a groove.

Claims (5)

In a robot stopper device that prevents movement of an arm exceeding a set range by causing the arm to collide with the head of a stopper bolt fixed at a predetermined position,
Formed in a mating member for fixing the stopper bolt, and a through hole for passing the stopper bolt;
A screw hole formed at the bottom of the through hole and screwing the screw portion of the stopper bolt;
The counterpart member is formed to extend in the collision direction of the arm from the through hole to the stopper bolt, and has a groove narrower than the shaft diameter of the stopper bolt,
When the stopper bolt is collided with the arm and deforms beyond a predetermined amount, the stopper device of the robot enters into the groove from the through hole while deforming both side portions of the groove.   The robot stopper device according to claim 1, wherein a depth of the groove is equal to or greater than a diameter dimension of the stopper bolt. 2. The distance L from the center of the through hole to the tip of the groove satisfies the following expression, where d is the axial diameter of the stopper bolt and W is the width of the groove. Or the stopper apparatus of the robot of 2.
L> W / 2 + [(d / 2) ² − (W / 2) ² ] ^1/2 4. The robot stopper device according to claim 1, wherein the width W of the groove satisfies the following expression when the shaft diameter of the stopper bolt is d. 5.
0.7d ≦ W <d   5. The robot stopper device according to claim 1, wherein a width of the groove is formed to become narrower as the distance from the through hole increases. 6.

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