JP2801643B2 - Stop device for industrial robot - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a stop device for preventing a movable member of an industrial robot from further moving beyond a predetermined “lower limit position”.

(Prior Art) In the above-mentioned robot, usually, a movable member is supported on a base as a base member so as to be able to move up and down in a vertical direction. The lower set position of the movable member is determined by an electronic control device. When the movable member moves down to reach the lower set position, for example, the movable member is automatically set at the set position. It can be stopped or automatically raised from the set position.

In the above configuration, in a case where the control device is broken down and the movable member further descends beyond the set position, some inconvenience may occur,
At a predetermined "lower limit position" beyond the set position, a stop device for emergency-stopping the movable member is provided.

Conventionally, as the above-mentioned stopping device, for example, there is a device configured as follows.

That is, the position sensor is attached to the base side,
An object to be detected is attached to the movable member. When the movable member descends and reaches the “lower limit position”, the object to be detected that descends together with the movable member corresponds to an area that can be detected by the position sensor (hereinafter simply referred to as “ ), The position sensor outputs a detection signal. Further, a brake for inputting this signal and braking the movable member is provided.

Therefore, when the movable member reaches the "lower limit position", the movable member is automatically stopped at that position by the brake.

By the way, if the movable member is stopped at the “lower limit position” as described above, it is necessary to inspect and repair the movable member, so that the movable member is temporarily raised from this position and returned to the origin position of the robot. Although it is necessary, if the object to be detected corresponds to the position sensor, the movable member is kept stopped by the braking action of the brake, and therefore, the movable member is raised in this state. Can not do.

Therefore, in this case, conventionally, the switch of the position sensor is once turned off (off) to release the braking action of the brake, thereby raising the movable member.

On the other hand, if the movable member descends beyond the “lower limit position” for some reason, the movable member may collide with some other object. A stopper for forcibly stopping the lowering of the movable member beyond the “lower limit position” is attached to the base member.

(Problems to be Solved by the Invention) By the way, as described above, when the switch of the position sensor is turned off in order to raise the movable member stopped at the “lower limit position”, After raising the members or completing the repair work, it is necessary to return the switch to the original ON state, but such work is easy to forget, and if you forget this, When the movable member exceeds the "lower limit position", its lowering is stopped by the stopper. However, this stop is forcible and may cause unnecessary external force to be applied to the movable member and the like. For this reason, stopping the movable member by the above-described stopper should be avoided as much as possible, and is not preferable.

(Object of the Invention) The present invention has been made in view of the above-mentioned circumstances, and has been described in which the movable member reaches a predetermined "lower limit position" and is automatically stopped by a brake. When the work for returning to the home position is performed, due to this work, the movable member is thereafter moved to the “lower limit position”.
Is reached, the moving member is further lowered, and the lowered movable member is forcibly stopped by the stopper, so that the inconvenience that unnecessary external force is applied to the movable member does not occur. The purpose is to:

(Structure of the Invention) A feature of the present invention for achieving the above object is that the movable member 4 is supported on the base member 2 so as to be able to move up and down in the vertical direction, and the position sensor 43 and the detected object are detected by the base member 2. body
One of the two components 45 (position sensor 43) is attached, and the other component (detected body 45) of the movable member 4 is attached. When the position reaches, the other component (detected body 45) lowered together with the movable member 4 causes the position sensor 43 to output a detection signal corresponding to the one component (position sensor 43), and A brake 33 for inputting this signal to stop the movable member 4 is provided, and a stopper 38 is attached to the base member 2 to stop the movable member 4 that has been lowered beyond the “lower limit position” by contacting the base member 2. (1) While the movable member 4 is stopped by the brake 33 at the “lower limit position”, the base member 2
The position of the one part (position sensor 43) can be changed in a vertical "predetermined range" including at least below the mounting position, and (2) the mounting position is changed to a lowermost portion in the "predetermined range". The position of the movable member 4 stopped by the brake 33 in correspondence with the one component (the position sensor 43) and the other component (the detection object 45) comes into contact with the stopper 38 and stops. The point is that it is located above the position of the movable member 4 to be made.

(Operation) The operation of the above configuration is as follows.

When the movable member 4 descends and reaches a predetermined "lower limit position", the other component (detected body 45) descended together with the movable member 4 is attached to one component (position sensor 43) attached to the base member 2. Correspondingly, the position sensor 43 outputs a detection signal, and the brake 33 that has received this signal operates to control the movable member 4. As a result, the movable member 4 is automatically stopped at the “lower limit position”, so that the movable member 4 descends beyond the “lower limit position”, which may cause some inconvenience. Be avoided.

When the movable member 4 is to be lifted from the above state, one component (position sensor) for the base member 2 is required.
The mounting position of 43) is changed downward in the “predetermined range” from the mounting position corresponding to the above “lower limit position”. Then, the correspondence between the two components (the position sensor 43 and the detection object 45) is released, and the operation of the brake 33 is released, so that the movable member 4 can be raised. In addition, even if the movable member 4 is raised from this state, the other component (detected body 45) that rises together with the movable member 4 does not correspond to the one component (the position sensor 43). ,
The upward movement of the movable member 4 is not braked by the brake 33. Therefore, the movable member 4 is moved to the “lower limit position”.
Thus, the movable member 4 can be raised and returned to the original state from the state stopped by the brake 33.

After the movable member 4 is raised as described above or after the repair work is completed, it is required that the one component (the position sensor 43) be changed back to the original mounting position. Even if this mounting position is forgotten, when the movable member 4 further descends from the "lower limit position", the other component (detected body 45) descending together with the movable member 4 is moved to the above position. The brake 33 is operated in the same manner as described above in response to one of the components (the position sensor 43) again, and the movable member 4 is stopped.

Also, as described above, one of the components (position sensor 4
When the mounting position of 3) is changed below the mounting position corresponding to the "lower limit position", the one component (position sensor 43) whose mounting position has been changed to the lowermost position in the "predetermined range" is changed. , The other part (detected object 4
5) corresponds to the position of the movable member 4 stopped by the brake 33 (indicated by a two-dot chain line in FIG. 1). 1 (dashed line in FIG. 1).

For this reason, as described above, even if the mounting position of one component (the position sensor 43) is changed below the mounting position corresponding to the “lower limit position” to the lowermost portion of the “predetermined range”, Before the movable member 4 descending beyond the “lower limit position” is forcibly stopped by contacting the stopper 38, the other component (detected body 45) descending with the movable member 4 is one of the components. Parts (position sensor
43), the lowering of the movable member 4 corresponds to the brake
It will be stopped by 33.

Therefore, the occurrence of the inconvenience that the movable member 4 descending beyond the “lower limit position” is forcibly stopped by the stopper 38 and an unnecessary external force is applied to the movable member 4 is suppressed.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

In FIG. 2, reference numeral 1 denotes an industrial robot. The robot 1 has a base member 2, and a cylindrical movable member 4 on a Z axis 3 whose axis extends in a vertical direction is supported on the base member 2 so as to be able to move up and down along the Z axis 3. I have. A first arm 5 is pivotally supported on the upper end of the movable member 4 so as to be rotatable around the Z-axis 3, and a second arm 6 is parallel to the Z-axis 3 at a rotating end of the first arm 5. It is pivotally supported so as to be rotatable around a major axis. A tool 7 is attached to the rotating end of the second arm 6, and the movable member 4, the first arm 5, and the second arm 6 are automatically operated by automatically controlling the robot 1. Thus, the tool 7 performs a predetermined operation on the workpiece.

3 to 5. The base member 2 has a case-shaped cast base body 10 and a base case 11 screwed onto the base body 10. The base case 11 is divided into two parts in plan view, and one of the divided parts is a cast thick part 12 and the other is a sheet metal part 13 which is screwed to each other.

A ball screw 16 is supported on the base case 11 by a bearing 15 so as to be rotatable about an axis parallel to the Z-axis 3. A bearing for preventing the bearing 15 from coming off is provided on the upper surface of the base body 10. The presser 17 is screwed by a bolt screw 18.

Reference numeral 20 denotes a bracket, and a nut 21 is screwed to the bracket 20 with a bolt 22. The nut 21 is fitted around the ball screw 16 to form a large number of balls (not shown).
And the ball screw 16 is screwed together. Therefore, when the ball screw 16 is rotated around its axis, the nut 12 screwed to the ball screw 16 moves up and down, and the bracket 20 moves up and down accordingly.

A pair of guide rails 24, 24 extending parallel to the Z-axis 3 are screwed to bolts 25 on the inner surface of the thick portion 12 of the base case 11.
26 are fitted slidably up and down, and each slider 26 is screwed to the bracket 20 by a bolt 27.

Therefore, as described above, when the bracket 20 moves up and down, the bracket 20 is guided by each guide rail 24 and moves accurately in parallel with the Z axis 3. Then, the movable member 4 is provided on the bracket 20 with bolts 28.
The movable member 4 is moved up and down by moving the bracket 20 up and down.

In the above case, the pair of sliders 26, 26 are vertically displaced from each other. The upper end of the ball screw 16 passes through a through hole 29 formed at the lower end of the movable member 4 and is housed in the movable member 4.

On the base body 10, an electric motor 32 and a brake 33 are supported. Ball screw 16 in the base body 10
, An output shaft 34 of the electric motor 32, and an input shaft 35 of the brake 33 are respectively provided with pulleys 36, and a belt 37 is wound around these pulleys 36. When the electric motor 32 operates, the rotation of the output shaft 34 is accurately transmitted to the ball screw 16 and the input shaft 35 of the brake 33 via the belt 37 and the like, and the operation of the electric motor 32
The movable member 4 can be moved up and down accurately through the connection member 20. The brake 33 functions as an emergency. When the brake 33 operates, the movable member 4 is stopped from moving up and down. The belt 37 may be a chain or the like in addition to the toothed belt.

In FIGS. 1, 3 and 5, if the movable member 4 is excessively lowered, the bracket 20 may collide with the upper surface of the base body 10 and cause mechanical damage.
Therefore, an elastic stopper 38 made of urethane rubber is jointly fastened to the bolt 18 for the bearing retainer 17. The three stoppers 38 are provided on the bearing retainer 17 at equal intervals in the circumferential direction of the bearing retainer 17, and each of them protrudes upward. For this reason, when the movable member 4 is lowered to the lowermost position indicated by the dashed line in FIG. 1, the lower surface of the nut 21 is pressed against the stopper 38, and the impact at the time of the collision is absorbed.

In FIG. 1 and FIGS. 3 to 6, when the movable member 4 descends and reaches a predetermined “lower limit position” indicated by a solid line in each figure, the movable member 4 is emergency stopped. A stop device 39 is provided. The stop device 39 will be described below.

A long hole 40 extending parallel to the Z axis 3 is formed in the thick portion 12, and a pair of upper and lower mounting bolts 41, 41 are inserted into the long hole 40 from the outer surface side of the thick portion 12. On the other hand, a support plate 42 is provided on the inner surface side of the thick portion 12 so as to be vertically slidable. The support plate 42 is detachably screwed to the thick portion 12 by the mounting bolts 41, 41. A position sensor 43, which is a proximity switch, is attached to the support plate 42, and the position sensor 43 forms a component of the stop device 39.

Loosen the mounting bolts 41, 41 a little, and
If the support plate 42 and the position sensor 43 are integrally moved up and down along the long hole 40, the support plate 42
, The position of the position sensor 43 can be changed. That is, the mounting position of the position sensor 43 with respect to the base member 2 can be changed within a “predetermined range” in the vertical direction corresponding to the length of the long hole 40.

In the state shown by the solid line in each figure, the position sensor 43 is
In other words, the position of the position sensor 43 with respect to the base member 2 is the uppermost part of the “predetermined range”. Can be changed in the above-mentioned "predetermined range" in the up-down direction including below the above-mentioned mounting position.

On the other hand, a detection object 45 which is a magnetic bolt is screwed to the bracket 20 serving as the movable member 4 side.
Constitute a part of the stop device 39. In addition, as shown in FIG. 4, the electric motor 32, the brake 33, and the position sensor 43 are connected to each other by an electronic control unit 46.

By the operation of the electric motor 32, the movable member 4 is lowered as described above, and this is the "lower limit position" indicated by a solid line in each figure.
Is reached, the detected object 45 descending with the movable member 4 corresponds to the position sensor 43. At this time, the position sensor 43 is
A detection signal is output via 46 and this is
And input to the brake 33.

Then, the motor 32 stops its operation and its output shaft 34
At the same time, the brake 33 is actuated and the movable member 4 is braked via the belt 37, the ball screw 16 and the bracket 20, and the movable member 4 is automatically stopped at the "lower limit position". . That is, the mounting position of the position sensor 43 is a mounting position corresponding to the “lower limit position” of the movable member 4.

In the above case, the mounting position of the position sensor 43 with respect to the base member 2 can be changed in the "predetermined range" while the movable member 4 is stopped by the brake 33 at the "lower limit position". ing. More specifically, the mounting bolts 41, 41 are slightly loosened and moved downward to the lower end of the elongated hole 40 as shown by the two-dot chain line in FIGS. 1, 5, and 6. Here, when the mounting position of the position sensor 43 is changed, that is, when the mounting position of the position sensor 43 is changed to the lowermost part in the “predetermined range”,
The detection object 45 indicated by the solid line is released from corresponding to the position sensor 43. Then, in this manner, the operation of the electric motor 32 becomes possible via the control device 46, and the operation of the brake 33 is stopped, whereby the rotation of the ball screw 16 becomes possible.

Therefore, when the electric motor 32 is operated from this state, the movable member 4 is raised, whereby the inspection and repair of the robot 1 can be performed. Further, in this case, since the position sensor 43 is located below the detected object 45,
When the movable member 4 is raised, the detected object 45 that rises with the movable member 4 does not correspond to the position sensor 43, and therefore, the movable member 4 is raised without being braked by the brake 33.

After the movable member 4 is lifted or after the repair work is completed, the position sensor 43 is required to be changed back to the original mounting position. If so, the movable member 4 is further moved from the "lower limit position" indicated by a solid line in each of FIGS.
5 and 6, when the detection object 45 descending together with the movable member 4 corresponds to the position sensor 43 again, the brake 33 is moved in the same manner as described above. Operates, and the movable member 4 is stopped.

Further, as described above, when the mounting position of the position sensor 43 is changed below the mounting position corresponding to the “lower limit position”, the position where the mounting position is changed to the lowest position in the “predetermined range” is changed. The position (the two-dot chain line in FIG. 1) of the movable member 4 at which the detection object 45 is stopped by the brake 33 in correspondence with the sensor 43 is brought into contact with the stopper 38 and stopped. The position is higher than the position of the member 4 (the dashed line in FIG. 1).

Therefore, as described above, the mounting position of the position sensor 43 is below the mounting position corresponding to the "lower limit position",
Even if the movable member 4 is lowered to the lowermost part of the "predetermined range", the movable member 4 descending beyond the "lower limit position" is forcibly stopped by contacting the stopper 38. The detection object 45 descending with the position sensor 43 corresponds to the position sensor 43, and the lowering of the movable member 4 is stopped by the brake 33.

Therefore, the occurrence of the inconvenience that the movable member 4 descending beyond the “lower limit position” is forcibly stopped by the stopper 38 and an unnecessary external force is applied to the movable member 4 is suppressed. That is, fail-safe is considered.

Although the above description is based on the illustrated example, the position sensor 43
The position sensor 43 may be attached to the movable member 4, and the object 45 may be attached to the base member 2. Further, the stopping device 39 includes the movable member 4 and the first arm 5.
May be provided between the first arm 5 and the second arm 6. Further, the robot 1 may be of any type other than the articulated type, such as a cylindrical coordinate type.

(Effects of the Invention) According to the present invention, the movable member is supported on the base member so as to be able to move up and down in the vertical direction, and one of the two components of the position sensor and the object to be detected is attached to the base member. Attach the other part to the member, and when the movable member reaches a predetermined "lower limit position" during its lowering, the other part lowered together with the movable member moves the position sensor corresponding to the one part. Output detection signal,
Further, a brake for inputting this signal to stop the movable member is provided, and a stopper for abutting and stopping the lowered movable member exceeding the “lower limit position” is attached to the base member. In the stopping device, (1) in a state where the movable member is stopped by the brake at the “lower limit position”, a “predetermined vertical” including at least a position below the mounting position of the one component with respect to the base member; The mounting position can be changed in the range.

For this reason, the movable member descends and the “lower limit position”
When the position of the movable member is reached, the other component that has descended together with the movable member corresponds to one of the components attached to the base member, and the position sensor outputs a detection signal, and the brake that receives the signal is actuated to move. The member is braked. Since the movable member is automatically stopped at the “lower limit position” by this, it is avoided that the movable member descends beyond the “lower limit position” to cause any inconvenience. You.

When trying to raise the movable member from the above state, the mounting position of the one component with respect to the base member is changed to be lower than the mounting position corresponding to the "lower limit position" by "a predetermined range". Then, the correspondence between the two parts is released, and the operation of the brake is released, so that the movable member can be raised. Also, even if the movable member is raised from this state, the other component that rises with the movable member does not correspond to the one component, and therefore, the rise of the movable member is braked by the brake. There is no. Therefore, it is possible to raise the movable member from the state where the movable member is stopped by the brake at the “lower limit position” and return the movable member to the original state.

Also, after raising the movable member as described above,
After completion of the repair work, it is required to change the one of the above-mentioned parts to the original mounting position, but even if this mounting position is forgotten, the movable part is thereafter moved to the above-mentioned "lower limit position". From the above, the other component descending with the movable member again corresponds to the one component, the brake is operated in the same manner as described above, and the movable member is stopped.

Therefore, as described above, even if the user forgets to reset the mounting position of the movable member, it is possible to prevent the movable member from descending greatly and causing any inconvenience.

(2) The position of the movable member, which is stopped by the brake corresponding to the one component whose mounting position has been changed to the lowermost portion in the “predetermined range”, corresponds to the stopper. The movable member is positioned above the position of the movable member to be stopped by contact.

For this reason, as described above, even if the mounting position of one of the components is changed below the mounting position corresponding to the “lower limit position” to the lowest portion of the “predetermined range”, the “lower limit position” is not changed. Before the movable member descending beyond the stopper is forcibly stopped by contacting the stopper, the other component descending together with the movable member corresponds to the one component, and the descending of the movable member corresponds to the one component. It will be stopped by the brake.

Therefore, the occurrence of the inconvenience that the movable member descending beyond the “lower limit position” is forcibly stopped by the stopper and an unnecessary external force is applied to the movable member is suppressed.

[Brief description of the drawings]

1 shows an embodiment of the present invention. FIG. 1 is a partially enlarged view of FIG. 5, FIG. 2 is an overall side view, FIG. 3 is a partially enlarged sectional view of FIG. 2, and FIG. 5 is a sectional view taken along the line IV-IV of FIG. 5, FIG. 5 is a sectional view taken along the line VV of FIG. 3, and FIG. 6 is a perspective view of the proximity switch. 1 ... Robot, 2 ... Base member, 3 ... Z axis, 4 ... Movable member, 33 ... Brake, 39 ... Stop device, 43 ... Position sensor (one part), 45 ... Detected Body (the other part).

Claims (1)

(57) [Claims] A movable member is supported on a base member so as to be able to move up and down in a vertical direction, and one of two parts of a position sensor and an object to be detected is attached to the base member, and the other part is attached to the movable member. Attachment, when the movable member reaches a predetermined lower limit position in the middle of its lowering, the other part that has been lowered together with the movable member outputs a detection signal corresponding to the one part, and the position sensor outputs a detection signal, A stop device for an industrial robot having a brake for inputting this signal and stopping the movable member, and a stopper attached to the base member for stopping the movable member which has descended beyond the lower limit position by contacting the movable member. (1) At least the mounting position of the one component with respect to the base member in a state where the movable member is stopped by the brake at the lower limit position The mounting position can be changed in a predetermined range in the vertical direction including the lower part. (2) The one part whose mounting position has been changed to the lowermost part in the predetermined range corresponds to the other part and is stopped by the brake. A stopping device for an industrial robot, wherein a position of the movable member is higher than a position of the movable member stopped by contacting the stopper.