JP2007190656A - Rotary part protecting mechanism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive rotary part protecting mechanism for use in a joint of a robot and a moving mechanism using wheels. <P>SOLUTION: This rotary part protecting mechanism includes: a motor 1; a plate 3 rotating with an output shaft 1a of a motor and having a plane orthogonal to the output shaft; a rotor 7 provided opposite to the plate 3 through a space A and rotatable on the same axis as the output shaft of a driving source; a steel ball 13 provided on the rotor 7 and abutted on the plate 3; a spring 15 for energizing the steel ball 13; a conical recessed part 21 formed on the plate 3; a stopper mechanism 35 for inhibiting the steel ball 13 from being released from the recessed part 21; a positional shifting detecting means 41 for detecting shifting in the rotation direction to the plate 3 of the rotor 7; and a control part entering a back drive mode for relaxing the driving torque of the driving source when the positional shifting detecting means 41 responds. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a rotating part protection mechanism used in a robot's joint, a moving mechanism using wheels, and the like.

Robot joints and moving mechanisms are roughly classified into a driving source and a rotating body that is rotationally driven by the driving source.
When a large load is applied to the rotating body, a torque limiter such as a friction clutch is provided between the output shaft of the drive source and the rotating body. When a large load is applied to the rotating body, the torque limiter slips. A load is prevented from acting on the drive source (see, for example, Patent Document 1).
JP 2000-280195 A (see paragraph 0073, FIG. 9)

  However, when a torque limiter such as a friction clutch is provided, when a large load is applied and the torque limiter is activated, only the rotating body driven by the driving source rotates, and the driving source and the rotating body are shifted. In order to remove the load and drive the rotating body again, it is necessary to return the rotating body to the position before the torque limiter operation.

In order to perform the return control, it is necessary to know the displacement (angle) of the rotating body, and an expensive sensor such as a potentiometer is required.
Even if this invention is made | formed in view of the said problem, the subject is providing the cheap rotation part protection mechanism.

  The invention according to claim 1, which solves the above problem, includes a drive source, a plate attached to the output shaft of the drive source, rotating with the output shaft, and having a plane perpendicular to the output shaft, and a plane of the plate A rotating body provided on one of the rotating body, the plate, and the rotating body. A slider capable of abutting against a plane, a biasing means for biasing the slider in a direction to abut against the other plane, and a recess formed on the other plane of the plate and the rotating body. A first inclined surface whose depth gradually increases in a clockwise direction from the edge of the recess toward the center along the circumference centered on the rotation center, and the edge of the recess Counterclockwise direction from center to center A recess having a second slope that can be brought into contact with the slider, and a recess formed on the other plane of the plate and the rotary body, the center being the center of rotation. A concave portion having a first slope and a second slope along which the depth gradually increases in the clockwise direction and the counterclockwise direction from the edge of the recess toward the center along the circumference, and the slider can come into contact therewith. A stopper mechanism that prohibits the slider from being detached from the recess, a displacement detection unit that detects a displacement of the rotating body in the rotational direction with respect to the plate, and a signal from the displacement detection unit, When the displacement detection means responds, the drive mode of the drive source is relaxed. When the displacement detection means stops responding, the drive source is controlled in the normal control mode. A control unit comprising a rotating portion protection mechanism, characterized in that it consists of.

  When no load is applied to the rotating body, the slider urged by the urging means is located at the center of the recess. Then, when the drive source is driven and the plate rotates, the rotating body is caused by the fitting force between the slider and the recess (the force determined by the frictional force generated between the slider and the groove and the biasing force of the biasing means). Rotates integrally with the plate, and the rotation of the drive source is transmitted to the rotating body.

  When a load greater than the fitting force between the slider and the recess acts on the rotating body, the slider climbs on the first slope or the second slope of the recess. That is, the rotating body is displaced from the plate. Due to the displacement of the rotating body, the displacement detection means responds, and the control unit enters a back drive mode in which the drive force of the drive source is reduced. In this specification, the “back drive mode for relaxing the drive torque of the drive source” includes, but is not limited to, servo-off, control gain change, drive source stop, and the like.

  Further, when the rotating body moves with respect to the plate until the slider is detached from the recess, the stopper mechanism prohibits the slider from being detached from the recess. The drive source can be back driven by a load.

  Next, when the load acting on the rotating body is eliminated, the slider descends the first slope and the second slope by the fitting force between the slider and the recess, and is positioned again at the center of the recess. That is, it returns to the original position, and the rotating body also returns to the position before the load is applied to the plate. When the rotating body returns to the original position, the position deviation detecting means stops responding, and the control unit returns to the normal control mode.

The invention according to claim 2 is the rotating portion protection mechanism according to claim 1, wherein the slider is one of a ball and a roller.
According to a third aspect of the present invention, the stopper mechanism is provided on one of the plate and the rotating body, the protrusion projecting toward the other plane, the plate, and the rotating body. The groove is provided on the other side, is formed along a circumference centered on the center of rotation with the protrusion engaging, and has a wall surface on which the protrusion can come into contact. The rotating part protection mechanism according to claim 1 or 2.

The rotating body can rotate with respect to the plate as long as the protrusion comes into contact with the wall surface of the end of the groove.
According to a fourth aspect of the present invention, the misregistration detection means is provided at a location other than the center of rotation of the rotating body and at a location other than the rotating body, and a detection unit is engaged with the groove. 4. The rotating part protection according to claim 1, further comprising: a microswitch that reacts when the rotating body is displaced with respect to the plate and moves away from the groove. 5. Mechanism.

  When the rotating body rotates with respect to the plate, the detection part of the microswitch is detached from the groove, and the microswitch is responsive.

  According to the first to fourth aspects of the present invention, a slider provided on one of the plate and the rotating body and capable of contacting the other plane, and a direction in which the slider abuts the other plane. And a recess formed on the other plane of the plate and the rotating body, and centered from the edge of the recess along a circumference centered on the center of rotation. A first slope on which the slider gradually contacts in the clockwise direction toward the portion, and a slider in which the depth gradually increases in the counterclockwise direction from the edge of the recess toward the center. Has a concave portion having a second inclined surface on which the slider can come into contact and a stopper mechanism for prohibiting the slider from detaching from the concave portion, a large load acts on the rotating body, and the plate and the rotating body are Even if it is misaligned, it affects the rotating body. When the load is lost, the rotating body is returned to the position of the previous state of the load to the plate acts.

Therefore, an expensive sensor such as a potentiometer for detecting the displacement (angle) of the rotating body is not required, and the rotating unit protection mechanism is inexpensive.
Further, by appropriately setting the magnitude of the urging force of the urging means and the inclination angles of the first slope and the second slope of the recess, the rigidity between the plate and the rotating body can be set high in a small space.

  Also, a displacement detection means for detecting the movement of the rotating body relative to the plate and a signal from the displacement detection means, and when the displacement detection means responds, the drive torque of the drive source is increased. When the back drive mode is relaxed and the response of the displacement detection means is lost, the drive source control has a control unit that is in a normal control mode, so that a large load does not act on the drive source, The drive source is not destroyed.

  According to the invention which concerns on Claim 2, the said slider rolls with respect to a recessed part by being either a ball | bowl or a roller. Therefore, the generation of abnormal noise is reduced compared to the slider that is in sliding contact with the recess.

  According to the invention of claim 3, the stopper mechanism prohibits rotation of the rotating body by abutment between the protrusion and the wall surface of the end of the groove. It can be carried out.

  According to the invention which concerns on Claim 4, a detection is reliable and it is cheap by using a microswitch.

  The overall configuration will be described with reference to FIGS. 1A and 1B are diagrams for explaining the entire rotating unit protection mechanism according to the present embodiment. FIG. 1A is a front view, FIG. 1B is a right side view of FIG. 1A, and FIG. FIG. 3 is a cross-sectional view taken along line AA, and FIG. 3 is a diagram for explaining the electrical configuration of this embodiment. The cutting line AA is a cutting line along the circumference centered on the rotation center of the rotating body 7.

  In the figure, the output shaft 1a of the motor 1 as a drive source is press-fitted into the hole 3a of the plate 3, and the output shaft 1a of the motor 1 and the plate 3 rotate together. The plate 3 has a plane 3b orthogonal to the output shaft 1a.

  A rotating body 7 is attached to the output shaft 1 a of the motor 1 via a bearing 5. In this embodiment, the output shaft 1 a is press-fitted into the inner ring of the bearing 5, and the outer ring of the bearing 5 is press-fitted into the hole 7 a of the rotating body 7. For this reason, the rotating body 7 is provided so as to be rotatable coaxially with the output shaft 1 a of the motor 1. The rotating body 7 has a flat surface 7 b that faces the flat surface 3 b of the plate 3 with a space A therebetween.

Four holes 11 are formed in the plane 7b of the rotating body 7 at a 90 ° pitch on the circumference centered on the rotation center.
Here, as shown in FIG. 2, a steel ball 13 as a slider capable of contacting the flat surface 3 b of the plate 3 is disposed in the opening 11 a portion of the hole 11. In the hole 11, a spring 15 is provided as an urging means whose one end abuts against the bottom surface 11 b of the hole 11 and whose other end pushes the steel ball 13. The steel ball 13 is pressed against the flat surface 3 b of the plate 3 by the urging force of the spring 15.

  The flat surface 3b of the plate 3 is formed with a recess 21 in which each steel ball 13 is engaged. The recess 21 in this embodiment is conical. On the conical surface of the recess 21, the steel ball 13 gradually becomes deeper in the clockwise direction from the edge 23 of the recess 21 toward the center 25 along the circumference centered on the rotation center of the plate 3. A first slope 27 on which the steel ball 13 can come into contact, and a second slope 29 on which the steel ball 13 can come into contact as the depth gradually increases in the counterclockwise direction from the edge 23 to the central portion 25 of the recess 21. Is formed.

  Returning again to FIG. 1, a stopper pin 31 is provided on the flat surface 3 b of the plate 3 as a protrusion protruding toward the flat surface 7 b of the rotating body 7. On the other hand, the stopper pin 31 engages with the flat surface 7b of the rotating body 7, is formed along a circumference centered on the rotation center of the rotating body 7, and a wall surface 33a on which the stopper pin 31 can come into contact with the end portion. , 33b are formed as arcuate grooves 33. Therefore, the rotating body 7 is rotatable in a range in which the stopper pin 31 contacts the wall surfaces 33a and 33b of the groove 33. The length of the groove 33 is set within a range in which the rotating body 7 rotates and the steel ball 13 does not leave the recess 21. Therefore, the stopper pin 31 and the groove 33 form a stopper mechanism 35 that prohibits the steel ball 13 from being detached from the recess 21.

Next, the positional deviation detection means 41 for detecting the rotational deviation of the rotating body 7 with respect to the plate 3 will be described. As shown in FIG. 1B, a groove 43 is formed on the peripheral surface of the rotating body 7.
Microswitches 45 are provided at locations other than the rotating body 7. The detection part 45a of the microswitch 45 is normally engaged with the groove 43, and is installed so that the detection part 45a is detached from the groove 43 and responds when the rotating body 7 is displaced with respect to the plate 3.

  Next, the electrical configuration of this embodiment will be described with reference to FIG. In the figure, 51 takes in a signal from the micro switch 45 of the position deviation detecting means 41, and when the micro switch 45 responds, the driving force of the motor 1 is reduced, and when the micro switch 45 stops responding, It is a control part which returns a driving force to the original state.

Here, the operation of the rotating portion protection mechanism of this embodiment will be described with reference to FIG. FIG. 4 is a diagram for explaining the displacement of the rotating body and the response of the microswitch due to the load acting on the rotating body.
When no load is applied to the rotating body 7, the steel ball 13 biased by the spring 15 is located at the center of the recess 21. When the motor 1 is driven and the plate 3 rotates, the rotating body 7 rotates together with the plate 3 by the fitting force between the steel ball 13 and the recess 21, and the rotation of the motor 1 is transmitted to the rotating body 7. Is done.

  Here, as shown in FIG. 4, when a load greater than the fitting force between the steel ball 13 and the recess 21 is applied to the rotating body 7, the steel ball 13 is moved to the first slope 27 or the second slope of the recess 21. 29 Start climbing up. That is, the steel ball 13 moves with respect to the concave portion 21, and the rotating body 7 starts to shift with respect to the plate 3 (time t1).

  When the rotating body 7 is further displaced, the detection part 45a of the micro switch 45 of the position deviation detecting means 41 is detached from the groove 43, and the micro switch 45 is actuated (time t2). The controller 51 is in a back drive mode in which the drive torque of the motor 1 is relaxed. In this embodiment, the motor 1 is stopped.

  Further, when the rotating body 7 moves with respect to the plate 3 until the steel ball 13 is detached from the recess 21, the stopper pin 31 of the stopper mechanism 35 comes into contact with the wall surface 33 a or the wall surface 33 b of the groove 33, and the recess 21 of the steel ball 13. Departure from is prohibited (time t3). Thereafter, the motor 1 is reversely driven (back driven) by the load.

  Next, when the load acting on the rotating body 7 is removed, the steel ball 13 starts to descend on the first slope 27 or the second slope 29 of the recess 21 (time t4). That is, the rotating body 7 starts to return toward the original position. And the detection part 45a of the micro switch 45 of the position shift detection means 41 is engaged with the groove 43 again, and the response of the micro switch 45 is stopped (time t5). The control unit 51 returns to the normal control mode before the load is applied. And the steel ball 13 is again located in the center part of the recessed part 21 (time t6). That is, the rotating body 7 returns to the position before the load is applied to the plate 3.

According to such a configuration, the following effects can be obtained.
(1) A steel ball 13 as a slider provided on the rotating body 7 and capable of contacting the flat surface 3b of the plate 3, and a biasing means for biasing the steel ball 13 in the direction of contacting the flat surface 3b of the plate 3 A spring 15 and a recess 21 formed in the flat surface 3b of the plate 3, and along the circumference centered on the rotation center of the plate 3, the depth is increased in the clockwise direction from the edge of the recess 21 toward the center. The first slope 27 on which the steel ball 13 can be brought into contact with the steel ball 13 gradually becomes deeper in the counterclockwise direction from the edge of the recess 21 toward the center, and the steel ball 13 can be brought into contact with the first slope 27. 2 and the stopper mechanism 35 for prohibiting the steel ball 13 from detaching from the recess 21, a large load acts on the rotating body 7, and the plate 3 and the rotating body 7 are Even if the position shift occurs, the negative acting on the rotating body 7 When there is no rotary member 7 returns to the position of the previous state acting load to the plate 3.

Therefore, an expensive sensor such as a potentiometer for detecting the amount of displacement of the rotating body 7 is not required, and the rotating portion protection mechanism is inexpensive.
(2) By appropriately setting the magnitude of the urging force of the spring 15 and the inclination angles of the first inclined surface 27 and the second inclined surface 29 of the recess 21, the rigidity between the plate 3 and the rotating body 7 in a small space. Can be set high.
(3) The positional deviation detecting means 41 having the micro switch 45 for detecting the movement of the rotating body 7 with respect to the plate 3 and the signal from the micro switch 45 of the positional deviation detecting means 41 are taken in, and the micro switch 45 is responsive. Then, a back drive mode for relaxing the drive torque of the motor 1 is established, and when the response of the micro switch 45 is lost, the motor 1 has a control unit 51 in which the control of the motor 1 becomes a normal control mode. It does not act and the motor 1 is not destroyed.
(4) Since the steel ball (ball) 13 is used as the slider, it rolls relative to the recess 21. Therefore, the generation of abnormal noise is reduced compared to the slider that is in sliding contact with the recess 21.
(5) The stopper mechanism 35 prohibits the rotation of the rotating body 7 by the contact between the stopper pin 31 as a protrusion and the wall surface 33a and the wall surface 33b at the end of the groove 33. 7 rotation regulation can be performed.
(6) The misregistration detection means 41 uses the microswitch 45, so that the detection is reliable and inexpensive.

  The present invention is not limited to the above embodiment. In the above embodiment, the steel ball (ball) 13 is used as the slider, but a roller 101 may be used as shown in FIG. In this case, as shown in FIG. 5, the recess 103 gradually increases in depth in the clockwise direction from the edge 105 to the center 107 of the recess 205 along the circumference centered on the rotation center of the plate. A first slope 109 on which the roller 101 can come into contact, and a second slope 111 on which the depth gradually increases in the counterclockwise direction from the edge 105 of the recess 103 toward the central portion 107 and on which the roller 101 can come into contact. Just have it. Further, in the case of such a recess 103, the slider may be a pin with a sharp tip, or a rod-shaped member having an oblique cutting plane that can be brought into sliding contact with the first slope 109 and the second slope 111, respectively. May be.

Further, although the slider is provided on the rotating body 7 and the concave portion is provided on the plate 3, the slider may be provided on the plate 3 and the concave portion may be provided on the rotating body 7.
Furthermore, although the stopper pin 31 of the stopper mechanism 35 is provided on the plate 3 and the groove 33 is provided on the rotating body 7, the stopper pin may be provided on the rotating body 7 and the groove 3 may be provided on the plate 3.

  Further, although the groove 43 and the micro switch 45 are used as the positional deviation detection means, the present invention is not limited to this. For example, one of the light emitting element and the light receiving element is provided on the rotating body, the other element is provided at a place other than the rotating body, and the light from the light emitting element is emitted toward the light receiving element. You may make it detect the shift | offset | difference of a rotary body by response.

It is a figure explaining the whole rotation part protection mechanism of a form example, (a) A figure is a front view, (b) A figure is a right view of (a) figure. It is sectional drawing in the cutting line AA of FIG.1 (b). It is a figure explaining the electrical constitution of the rotation part protection mechanism shown in FIG. It is a figure explaining the action | operation of the rotation part protection mechanism shown in FIG. It is a figure explaining the other form example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Drive source 1a Output shaft 3 Plate 7 Rotating body 13 Steel ball 15 Spring 21 Recess 35 Stopper mechanism 41 Position shift detection means 51 Control means

Claims (4)

A driving source;
A plate attached to the output shaft of the drive source, rotating with the output shaft, and having a plane perpendicular to the output shaft;
A rotating body having a plane opposed to the plane of the plate through a space, and provided rotatably on the same axis as the output shaft of the drive source;
A slider provided on one of the plate and the rotating body and capable of contacting the other plane;
An urging means for urging the slider in a direction in contact with the other plane;
A concave portion formed on the other plane of the plate and the rotating body, and deepened in a clockwise direction from an edge portion of the concave portion toward a central portion along a circumference centering on the rotation center. A first slope on which the slider can come into contact with a gradually increasing depth, and a second slope on which the slider can come into contact with a depth that gradually increases in the counterclockwise direction from the edge of the recess toward the center. A recess having
A stopper mechanism that prohibits the slider from being detached from the recess;
A displacement detection means for detecting a displacement in the rotational direction of the rotating body with respect to the plate;
When the signal from the positional deviation detection means is captured and the positional deviation detection means responds, the drive mode of the driving source is relaxed, and when the positional deviation detection means stops responding, the driving source A control unit in which control is in a normal control mode;
A rotating part protection mechanism comprising:   The rotating part protection mechanism according to claim 1, wherein the slider is one of a ball and a roller. The stopper mechanism is
A protrusion provided on one of the plate and the rotating body and protruding toward the other plane;
Provided on the other of the plate and the rotating body, the protrusion engages, is formed along a circumference centered on the rotation center, and a wall surface on which the protrusion can contact is formed at the end The rotating part protection mechanism according to claim 1, wherein the rotating part protection mechanism is a groove. The positional deviation detecting means is
A groove provided at a location other than the rotation center of the rotating body;
A micro switch provided at a location other than the rotating body, and when the detecting portion is engaged with the groove and the rotating body is displaced with respect to the plate, the detecting portion is detached from the groove and responds;
The rotating part protection mechanism according to claim 1, comprising:

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