JPH0349716B2 - - Google Patents

Description

[Detailed description of the invention] [Technical field to which the invention pertains]

The present invention relates to a drive mechanism for an articulated manipulator for a nuclear reactor, which is intended for use as a manipulator that is inserted into the reactor through a standpipe installed at the top of the reactor to perform various inspections, simple repairs, etc. inside the reactor.

[Prior art and its problems]

As shown above, the manipulator is inserted into the furnace, and the work unit attached to the end of the arm is connected to the manipulator.
Articulated manipulators are known that are equipped with a TV camera to visually inspect the inside of the furnace using a monitor, or are further equipped with a workpiece such as a grab mechanism to perform various operations inside the furnace. An outline of the multi-joint manipulator used in the above-mentioned principle furnace will now be described with reference to FIG. 3.
In the figure, 1 is a pressure vessel of the principle reactor that houses the reactor core, 2 and 3 are primary and secondary shields, 4 is a stand pipe that penetrates the primary shield 2 and is installed on the top surface of the pressure vessel 1, 5 1 is a charge plate inside the reactor, 6 is a fuel control rod loaded into the reactor core through the stand pipe 4, and 7 is an articulated manipulator to which the present invention is applied. The manipulator 7 is loaded into the furnace from the floor of the secondary shield 3 through a guide pipe 8 installed in the stand pipe 4, and is remotely operated via a drive device 9 in response to a command given to an operation panel (not shown). be steered. As is well known, the manipulator 7 constitutes an articulated manipulator arm with multiple stages of links interconnected in series through joints, and a servo motor built into the casing of each link serves as an actuator. The work unit 10, such as a TV camera attached to the end link of the arm, can be routed within the furnace by rotating the end link and rotating the joints between each link via the joint drive mechanism. Move around and perform various inspections and work. Note that the illustration shows a state in which the situation inside the high-temperature gas duct 1a of the pressure vessel 1 is being monitored by a TV camera. Incidentally, this type of multi-joint manipulator is widely used not only for use in nuclear reactors but also as arms for industrial robots. Furthermore, in the unlikely event that a failure occurs during operation, the manipulators incorporated in these industrial robots can stop the operation of the robot and allow maintenance personnel to approach the machine and carry out necessary repair measures. However, with the articulated manipulator shown in Figure 3, which is inserted into the nuclear reactor and used, even if a failure occurs in the drive system during use, maintenance personnel cannot access the manipulator. In order to repair a malfunctioning part, the manipulator must be pulled out of the furnace through a standpipe. For this reason, manipulators for principle reactors are designed to automatically correct the arm's posture in the event of a failure, regardless of the arm's posture during use, and to be able to pull it out of the reactor through the standpipe of the reactor and recover it. It is necessary.

[Purpose of the invention]

This invention was made in consideration of the above points, and even if a failure occurs in the drive system of the manipulator while the manipulator is inserted into the reactor and used, the arm of the manipulator will be able to operate on its own. The purpose of the present invention is to provide a highly reliable drive mechanism for a multi-jointed manipulator for use in a nuclear reactor, in which the manipulator can be corrected to a recoverable posture and pulled out of the reactor through a standpipe to be recovered.

[Key points of the invention]

In order to achieve the above object, the present invention interposes a non-excitation operated electromagnetic clutch and a non-excitation operated electromagnetic brake in series between the output shaft of a servo motor, which is the actuator of the drive mechanism, and the reduction mechanism. It is composed of With this configuration, if the servo motor becomes inoperable due to seizure, galling, etc. that causes the motor to lock while the manipulator is inserted into the reactor, the electromagnetic By opening the clutch and disconnecting the servo motor from the drive system, and further loosening the electromagnetic brake, the driven link can move freely and the manipulator can be pulled out of the furnace through the stand pipe and recovered. Also, by setting the maximum output torque of the servo motor to be greater than the braking torque of the brake, even if a failure occurs in the electromagnetic brake or its power supply system and it becomes impossible to release the brake, By increasing the output torque of the servo motor beyond the braking torque and forcibly driving the driven link to rotate, it becomes possible to correct the link's posture, and as before, the manipulator is pulled out of the reactor through the stand pipe. It can be recovered.

[Embodiments of the invention]

1 and 2 show an embodiment of the present invention, and the same members corresponding to FIG. 3 are given the same reference numerals. Here, FIG. 1 shows a joint between a tip link 7a holding a work unit 10 and a next stage link 7b among the multi-stage links constituting the manipulator arm. The drive mechanism is shown. That is, the links 1a and 1b are hinged together through a pin serving as a rotating shaft between the hinges 11a extending from each link casing 11, and the tip link 7a on the driven side is built into the casing 11 of the drive link 7b. A rotation drive mechanism 12 is installed, and the hinge is transmission-coupled so as to be driven to rotate in the direction of arrow A around the axis of rotation of the hinge. Here, the swing drive mechanism 12 uses a servo motor 13 as an actuator, and operates in a non-excited manner between this output shaft and a reduction gear of a Harmonic Drive (a product name of Harmonic Drive Systems Inc.) indicated by the reference numeral 14. A type electromagnetic clutch 15 and a non-excitation type electromagnetic brake 16 are installed in series, and a bevel gear 17 is connected to the output shaft of the reducer 14, and this gear 17 is integrated with the hinge on the link 7a side. It is constructed by directly connecting the bevel gear 18. Among the parts mentioned above, the electromagnetic clutch 15 has a built-in solenoid coil, and when it is not energized, the clutch plate is connected to transmit the power of the servo motor, and when the coil is energized, the clutch plate is separated by electromagnetic force. It is a non-excited electromagnetic clutch that operates to cut off power transmission. On the other hand, the electromagnetic brake 16 is a non-excitation type brake that releases braking when the built-in solenoid coil is energized, and that braking works in other non-energized states.
When the link 1a is driven to swing, the brake is released by excitation to transmit the power of the servo motor 13 to the driven link, and when the servo motor 13 is stopped, the excitation is released and the brake is applied to stop and hold the driven link at that position. . The braking torque of the electromagnetic brake 16 is set to a value larger than the normal driving torque of the servo motor 13, but smaller than the large torque of the servo motor. Next, a description will be given of the rotation drive operation of the interlink joint with the above configuration, and the procedure for dealing with a failure in the drive system during use. First, in order to drive the inter-link joint in a normal state, the electromagnetic clutch 15,
Bevel gear 17 via electromagnetic brake 16 and reducer 14
The gear 18 is rotated by the rotational driving force transmitted thereto, and the tip link 1a is thereby driven to rotate in the direction of arrow A around the rotation axis of the hinge. In this case, the turning angle of the tip link 7a is between the link 7a and the link 7a.
It is detected by a potentiometer 19 directly connected to the hinge rotation axis between the Also link 7a
When the link 7a is turned to a desired angle, the servo motor 13 is stopped, and at the same time, the electromagnetic brake 16 is applied to control the link 7a, so that the link 7a is stopped and held at that position. On the other hand, if the manipulator is used in a nuclear reactor with its arm bent as shown in Fig. 3, and the servo motor 13 seizes, galls, or otherwise malfunctions and becomes inoperable. First, the electromagnetic clutch 15 is energized by an external command to disengage the clutch and disconnect the servo motor 13 from the drive system. Next, in this state, by applying excitation to the electromagnetic brake 16 and loosening the brake, the tip link 7
A can move freely without restraint. If the link 7b is pivoted to a vertical position along the stand pipe 4 shown in FIG. The link posture is automatically corrected to a vertical posture by being aligned on a line, and as a result, the manipulator can be pulled out of the furnace through the stand pipe and recovered. In this case, by using the harmonic drive reducer described above as the reducer 14, the reduction gear can be rotated freely even from the driven side without causing self-lock unlike the worm gear type reducer. It's convenient. Further, the work unit 10 supported by the tip link 7a is disconnected from the tip link 7a and separated before the manipulator 7 is pulled out of the furnace, and is left on the charge plate 5 inside the furnace. In addition to the above-mentioned failure of the servo motor 13,
If the electromagnetic brake 1 should fail while the manipulator is in use.
If a failure occurs in 6 or its power supply system and the braking is not released even if excitation is applied, the output torque of the servo motor 13 is increased to drive with a torque higher than the braking torque of the electromagnetic brake 16. This makes it possible to overcome the braking force of the brake 16 and swing the tip link 7a to a desired position.

【Effect of the invention】

As described above, according to the present invention, a non-excitation type electromagnetic clutch and a non-excitation type electromagnetic clutch are provided between the output shaft of the servo motor that is the actuator of the joint drive mechanism between the links and the speed reduction mechanism. By installing an electromagnetic brake in series, even if a servo motor malfunctions while the manipulator is inserted into the reactor, the clutch and brake can be released. By freeing the movement between the links, the manipulator can be pulled out of the reactor and recovered through the standpipe. This makes it possible to provide an articulated manipulator for use in nuclear reactors that is highly reliable in handling. can.

[Brief explanation of drawings]

FIGS. 1 and 2 are a perspective view and a side view, respectively, showing the drive mechanism of the joint between links of an articulated manipulator for a nuclear reactor according to an embodiment of the present invention, and FIG. 3 is a state in which it is loaded into a nuclear reactor. 1 is a schematic configuration diagram of the entire articulated manipulator in FIG. In the figure, 1: Reactor pressure vessel, 4: Stand pipe,
7: Manipulator, 7a, 7b: Links of each stage, 10: Work unit, 11: Link casing, 12: Joint drive mechanism, 13: Servo motor, 14: Reducer, 15: Non-excitation operated electromagnetic clutch, 16 :Non-excitation type electromagnetic brake, 17,
18: Gear, A: Turning drive direction of driven link.

Claims (1)

[Claims] 1. An articulated manipulator that is used by being inserted into the reactor through a standpipe placed at the top of the reactor, and the manipulator arm is formed by multiple stages of links in series, each link being articulated. In this structure, the rotational drive of the joints between each link is performed via a drive mechanism built into the link casing on the drive side. A drive mechanism for an articulated manipulator for a nuclear reactor, comprising a non-excitation operated electromagnetic clutch and a non-excitation operated electromagnetic brake interposed in series. 2. In the drive mechanism set forth in claim 1, the braking torque of the electromagnetic brake is set to a value greater than the normal drive torque of the servo motor and smaller than the large output torque of the servo motor. Features a drive mechanism for an articulated manipulator for nuclear reactors.