JP2015044262A - Rotation drive mechanism and joint mechanism of robot provided with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotation drive mechanism which can suppress breakage of a motor or the like even when an overload is applied on the motor or the like without increasing the number of components.SOLUTION: A rotation drive mechanism 9 includes a pair of V-belts 94A, 94B which transmit rotation of motors 91A, 91B to side gears 92A, 92B by connecting output shafts 91A1, 91B1 of the motors 91A, 91B and input shafts 92A1, 92B1 of the side gears 92A, 92B. These V-belts 94A, 94B are designed so as to slide and spin out when the overload is applied on the output shafts 91A1, 91B1 of the motors 91A, 91B or the side gears 92A, 92B.

Description

  The present invention relates to a rotation drive mechanism that rotates a rotating body with a motor and a joint mechanism of a robot including the rotation drive mechanism.

2. Description of the Related Art Conventionally, a rotary drive mechanism that includes a motor and a rotating body that is rotated by the motor is known.
For example, a drive mechanism (rotation drive mechanism) described in Patent Document 1 is configured by connecting a motor, a plate cylinder (rotary body) rotated by the motor, an output shaft of the motor, and a plate cylinder. And a timing belt for transmitting the rotation of the drum to the plate cylinder. According to such a drive mechanism, since the rotation of the output shaft of the motor is transmitted to the plate cylinder via the timing belt, the motor can rotate the plate cylinder.
The drive mechanism described in Patent Document 1 includes an overload protection device such as a torque limiter provided between the output shaft of the motor and the timing belt. Since this overload protection device idles when an overload is applied to the output shaft or plate cylinder of the motor, it is possible to suppress damage to the motor or the like.

JP 2002-127581 A

  However, the drive mechanism described in Patent Document 1 has a problem in that the overload protection device has to be newly provided in order to suppress damage to the motor and the like, resulting in an increase in the number of parts and an increase in size.

  An object of the present invention is to provide a rotary drive mechanism capable of suppressing damage to a motor or the like even when an overload is applied to the motor or the like without increasing the number of parts, and a joint mechanism of a robot having the same It is to be.

  The rotation drive mechanism of the present invention is a rotation drive mechanism including a motor and a rotating body that is rotated by the motor, and the rotation of the motor is rotated by connecting the output shaft of the motor and the rotating body. The friction transmission belt is designed to slip and idle when an overload is applied to the output shaft or the rotating body of the motor.

Here, the friction transmission belt is a belt such as a flat belt or a V belt that uses a frictional force to transmit power. When such a friction transmission belt is employed in the rotational drive mechanism, the belt is designed with a sufficient margin so that the friction transmission belt does not run idle in order to reliably transmit power.
According to the present invention, the friction transmission belt is designed to slip and idle when an overload is applied to the output shaft or rotating body of the motor. Therefore, the rotational drive mechanism is used when an overload is applied to the motor or the like. Even if it exists, damage to a motor etc. can be suppressed. Further, since it is not necessary to newly provide a torque limiter or the like in order to suppress breakage of the motor or the like, the number of parts of the rotary drive mechanism is not increased.

  In the present invention, a sensor for detecting the rotation angle of the rotating body is provided, and the sensor is preferably provided in contact with the rotating body.

Here, in a conventional rotational drive mechanism including a motor and a rotating body rotated by the motor, when detecting the rotation angle of the rotating body, by attaching a sensor such as a potentiometer to the output shaft of the motor, A method of indirectly detecting the rotation angle of the rotating body is common. This is because when the speed reducer is interposed between the output shaft of the motor and the rotating body, the rotational speed of the motor is faster than the rotating speed of the rotating body, so the sensor is attached to the output shaft of the motor. This is because the rotation angle of the rotating body can be detected with higher resolution than when the sensor is attached to the rotating body. Further, by attaching the sensor to the output shaft of the motor, it is easier to route the cable such as the signal line as compared with the case where the sensor is attached to the rotating body.
However, if the friction transmission belt is designed so that it slips and slips when an overload is applied to the output shaft or rotating body of the motor as in the present invention, the friction transmission belt that has detected the rotation angle of the motor is idling. There is a problem that the rotation angle of the rotating body cannot be reliably detected.

  According to the present invention, since the sensor is provided in contact with the rotating body, the rotation angle of the rotating body can be reliably detected even when the friction transmission belt is idling. Therefore, the rotational drive mechanism can suppress damage to the motor or the like even when an overload is applied to the motor or the like without increasing the number of parts, and the friction drive belt is idle. Also, the rotation angle of the rotating body can be reliably detected.

  The joint mechanism of the robot according to the present invention includes the above-described rotation drive mechanism, and a control object that is provided on the rotating body and rotates with the rotation of the rotating body.

According to such a configuration, since the joint mechanism of the robot includes the above-described rotation drive mechanism, it is possible to achieve the same effects as the above-described rotation drive mechanism.
In addition, since the joint mechanism of the robot is equipped with the rotation drive mechanism described above, the motor, the rotating body, and the controlled object can be spaced apart and the limited space such as the arm can be used effectively. can do.
Since the robot joint mechanism needs to be positioned with high accuracy, high accuracy is required when detecting the rotation angle of the controlled object. According to the present invention, the joint mechanism of the robot can reliably detect the rotation angle of the rotating body with high accuracy even when the friction transmission belt is idled by providing the sensor in contact with the rotating body. it can.

The perspective view which shows the external appearance of the robot provided with the joint mechanism which concerns on one Embodiment of this invention. An enlarged view of the vicinity of the camera in the hand The figure which exposed the inside of the body part and the cover of the support part. Sectional drawing which cut | disconnected the rotational drive mechanism so that it might pass along the center axis | shaft of three spur gears

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view showing an appearance of a robot including a joint mechanism according to an embodiment of the present invention.
As shown in FIG. 1, the robot 1 is a manipulator placed on a traveling vehicle V that travels on the road. The robot 1 includes an attachment portion 2 for attachment to the traveling vehicle V, a columnar arm 3 provided on the attachment portion 2, a columnar arm 4 connected to the tip of the arm 3, and a tip of the arm 4. And a hand 5 connected to the.

The arm 3 is rotatably attached to the attachment portion 2 with an axis in the vertical direction of the paper surface as a rotation axis, and is rotatably attached to the attachment portion 2 with an axis orthogonal to this axis as a rotation axis.
The arm 4 is rotatably attached to the arm 3 with an axis orthogonal to the central axis of the arm 3 as a rotation axis.
The hand 5 includes a main body 51, two grippers 6 provided at the end of the main body 51 on the arm 4 side, and a camera 7 provided at the end of the main body 51 opposite to the gripper 6. I have.

  The robot 1 can move the work area by running the traveling vehicle V, and can drive the grippers 6 closer to the work object by driving the arms 3 and 4. Then, the robot 1 can perform a predetermined work by grasping or turning the work object with the gripper 6. At this time, the robot 1 can perform work with reference to an image captured by the camera 7.

FIG. 2 is an enlarged view of the vicinity of the camera 7 in the hand 5. In FIG. 2, the upper direction in the drawing is the + Z-axis direction, and of the two axes orthogonal to the Z-axis, the axis parallel to the central axis of the main body 51 is the X-axis, and Is described as the Y axis. The same applies to the following drawings.
The main body 51 and the camera 7 of the hand 5 are connected to each other via a joint mechanism 8 as shown in FIG.

  The joint mechanism 8 is provided on each side of the main body 51 in the Y-axis direction, and extends from the camera 7 toward the −Z-axis direction, and two extending portions 51A extending toward the −X-axis direction. In addition, a support portion 71 that supports the camera 7 is connected. Specifically, the support portion 71 is connected to the main body portion 51 so as to be sandwiched between the two extending portions 51A. The joint mechanism 8 connects the camera 7 to the main body 51 so as to be rotatable about the Y axis and to be rotatable about the Z axis.

FIG. 3 is a view in which the inside of the body portion 51 and the cover of the support portion 71 is seen through, and the inside is exposed. In FIG. 3, only the components that constitute the main part of the present invention are shown, and the other components are not shown.
As shown in FIG. 3, the main body 51 and the support 71 are connected to the main body 51 via a rotation driving mechanism 9 that rotates and bends and stretches the camera 7.

The rotation drive mechanism 9 is provided on the + X-axis direction side of the main body 51, and is provided on a pair of motors 91A and 91B provided on both sides in the Y-axis direction, and the support portion 71, and on the motors 91A and 91B A pair of side gears 92A and 92B as rotating bodies that are rotated in this manner, and a pinion 93 disposed between the side gears 92A and 92B so as to mesh with the side gears 92A and 92B, respectively. That is, the rotation drive mechanism 9 includes a differential gear device that includes side gears 92 </ b> A and 92 </ b> B and a pinion 93, and the pinion 93 is fixed to the end of the camera 7 on the −Z axis direction side.
In the present embodiment, the motor disposed on the left side of FIG. 3 is 91A, and the side gear is 92A. Further, the motor arranged on the right side of FIG. 3 is 91B, and the side gear is 92B. The side gears 92A and 92B and the pinion 93 employ bevel gears.

The rotation drive mechanism 9 transmits the rotation of the motors 91A and 91B to the side gears 92A and 92B by connecting the output shafts 91A1 and 91B1 of the motors 91A and 91B to the input shafts 92A1 and 92B1 of the side gears 92A and 92B. And a pair of V belts 94A and 94B as friction transmission belts.
Motor 91A and output shaft 91A1 are connected to each other via worm gear 91A2, and motor 91B and output shaft 91B1 are connected to each other via worm gear 91B2.

These V belts 94A and 94B are designed to slip and idle when an overload is applied to the output shafts 91A1 and 91B1 or the side gears 92A and 92B of the motors 91A and 91B.
In other words, when the overload is not applied to the output shafts 91A1 and 91B1 or the side gears 92A and 92B of the motors 91A and 91B, the side gear 92A can be rotated via the V belt 94A by rotating the motor 91A. it can. Further, the side gear 92B can be rotated via the V belt 94B by rotating the motor 91B.

According to such a joint mechanism 8, by rotating the pair of side gears 92 </ b> A and 92 </ b> B in the opposite directions, the pinion 93 can be rotated around the rotation axis of the pinion 93, and as a result, the camera can be moved with respect to the main body 51. 7 can be rotated around the Z axis.
Further, by rotating the pair of side gears 92A and 92B in the same direction, the camera 7 can be rotated around the rotation axis (Y axis) of the side gears 92A and 92B without rotating the pinion 93. The camera 7 can be bent and stretched with respect to 51.
Therefore, in the present embodiment, the camera 7 is a control target that is provided on the pair of side gears 92A and 92B serving as a rotating body and rotates with the rotation of the pair of side gears 92A and 92B.

  The rotation drive mechanism 9 is provided in contact with the input shaft 92B1 of the side gear 92B, and includes a potentiometer 95 as a sensor for detecting the rotation angle of the side gear 92B. Specifically, the potentiometer 95 is provided so as to mesh with a gear formed on the input shaft 92B1 of the side gear 92B, and to be engaged with the spur gear 95A, and is fixed to the input shaft of the potentiometer 95. Thus, a spur gear 95B that rotates the input shaft of the potentiometer 95 with its own rotation is provided. Therefore, the rotation of the input shaft 92B1 of the side gear 92B is transmitted to the input shaft of the potentiometer 95 via the spur gears 95A and 95B.

  Further, the rotation drive mechanism 9 includes a potentiometer 96 that detects the rotation angle of the camera 7. Specifically, the potentiometer 96 is fixed to a shaft body 97 inserted in a hole formed so as to penetrate along the rotation shafts of the side gears 92A and 92B and the pinion 93, thereby rotating the shaft body 97. A spur gear 96A that rotates with the rotation of the potentiometer 96, and a spur gear 96B that is fixed to the input shaft of the potentiometer 96 to rotate the input shaft of the potentiometer 96 with its own rotation. And a spur gear 96C provided so as to mesh with the gear. Therefore, the rotation of the shaft body 97 is transmitted to the input shaft of the potentiometer 96 via the spur gears 96A to 96C.

FIG. 4 is a cross-sectional view of the rotary drive mechanism 9 cut through the central axes of the three spur gears 96A to 96C.
As shown in FIG. 4, the shaft body 97 is a hollow shaft body having a T-shaped cross section that is slidably inserted into a hole formed so as to penetrate along the rotation shafts of the side gears 92A and 92B and the pinion 93. is there.
A cable C connected to the camera 7 passes through the shaft body 97. Since the cable C is connected to the camera 7 via the slip ring SR, the camera 7 can rotate indefinitely around the rotation axis of the pinion 93.

  Here, the rotation angle around the rotation axis of the side gears 92A and 92B in the camera 7 cannot be detected by the potentiometer 95 that detects the rotation angle of the input shaft 92B1 of the side gear 92B. This is because the side gear 92B is rotated even when the camera 7 is rotated around the rotation axis of the pinion 93 or when the camera 7 is bent or stretched around the rotation axis of the side gears 92A and 92B.

  On the other hand, since the shaft body 97 is slidably inserted in a hole formed so as to penetrate along the rotation shafts of the side gears 92A and 92B and the pinion 93, the camera 7 is connected to the rotation shaft of the pinion 93. When rotating around, the camera 7 does not rotate but only rotates when the camera 7 is bent and stretched around the rotation axis of the side gears 92A and 92B. Therefore, the rotation drive mechanism 9 can detect the rotation angle of the side gear 92A, 92B around the rotation axis in the camera 7 by detecting the rotation angle of the shaft body 97 with the potentiometer 96.

According to the present embodiment as described above, the following operations and effects can be achieved.
(1) Since the V-belts 94A and 94B are designed to slip and idle when an overload is applied to the output shafts 91A1 and 91B1 or the side gears 92A and 92B of the motors 91A and 91B, the rotary drive mechanism 9 includes the motor 91A. , 91B and the like can be prevented from being damaged even if an overload is applied. Further, since it is not necessary to newly provide a torque limiter or the like in order to suppress damage to the motors 91A, 91B, etc., the number of parts of the rotary drive mechanism 9 is not increased.

(2) Since the potentiometer 95 is provided in contact with the side gear 92B, the rotation angle of the side gear 92B can be reliably detected even when the V-belt 94B is idling. Therefore, the rotation drive mechanism 9 can suppress damage to the motors 91A, 91B, etc. even when an overload is applied to the motors 91A, 91B, etc., without increasing the number of parts, and the V belt 94A. , 94B can be reliably detected with high accuracy even when the rotation angles of 92A, 92B are idle.
(3) Since the joint mechanism 8 of the robot 1 includes the rotation drive mechanism 9, the motors 91A and 91B, the side gears 92A and 92B, and the camera 7 can be disposed apart from each other. The limited space can be used effectively.

Note that the present invention is not limited to the above-described embodiment, and modifications, improvements, and the like within a scope in which the object of the present invention can be achieved are included in the present invention.
For example, in the above-described embodiment, the potentiometer 95 is provided in contact with the side gear 92B. However, the potentiometer 95 may not be provided in contact. For example, by attaching a sensor such as a potentiometer to the output shaft of the motor, You may detect the rotation angle of a rotary body indirectly. Moreover, when it is not necessary to detect the rotation angle of a rotary body, the rotation drive mechanism does not need to be provided with a sensor.

  In the above-described embodiment, the camera 7 is used as the control target. However, a camera other than this may be used. For example, the gripper 6 may be adopted as a control target. In short, the control target may be provided as long as it is provided on the rotating body and rotates with the rotation of the rotating body.

  As described above, the present invention can be suitably used for a rotation drive mechanism and a joint mechanism of a robot including the rotation drive mechanism.

DESCRIPTION OF SYMBOLS 1 Robot 2 Mounting part 3, 4 Arm 5 Hand 6 Gripper 7 Camera (control object)
DESCRIPTION OF SYMBOLS 8 Joint mechanism 9 Rotation drive mechanism 51 Main body part 51A Extension part 71 Support part 91A, 91B Motor 91A1, 91B1 Output shaft 91A2, 91B2 Worm gear 92A, 92B Side gear (rotary body)
92A1, 92B1 Input shaft 93 Pinion 94A, 94B V-belt (friction drive belt)
95 Potentiometer (sensor)
95A, 95B Spur Gear 96 Potentiometer 96A-96C Spur Gear 97 Shaft C Cable SR Slip Ring V Traveling Vehicle

Claims (3)

A rotational drive mechanism comprising a motor and a rotating body rotated by the motor,
A friction transmission belt that transmits rotation of the motor to the rotating body by connecting the output shaft of the motor and the rotating body;
The rotary drive mechanism is characterized in that the friction transmission belt is designed to slip and idle when an overload is applied to the output shaft of the motor or the rotating body. In the rotation drive mechanism according to claim 1,
A sensor for detecting a rotation angle of the rotating body;
The rotation driving mechanism, wherein the sensor is provided in contact with the rotating body. The rotational drive mechanism according to claim 1 or 2,
A robot joint mechanism comprising a control object that is provided on the rotating body and that rotates with the rotation of the rotating body.

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