Conveyance method and conveyance apparatus
A conveyance method of conveying a conveyance target object by loading the conveyance target object on a slider, wherein the slider is connected to a ball nut threadably engaged with a ball screw shaft, includes a step of rotating the ball screw shaft by an electric motor, a step of applying a braking force which is a rotation resistance to the ball screw shaft by a non-electric resistance changing unit, and a step of setting at least one of a driving force of the electric motor and the braking force of the resistance changing unit so that the slider will stop when a predetermined external force acts on the slider during conveyance and changes the slider to an overload state regardless of the presence/absence of the conveyance target object loaded on the slider and a weight of the conveyance target object.
1. A conveyance method of conveying a conveyance target object by loading the conveyance target object on a slider, wherein the slider is connected to a ball nut threadably engaged with a ball screw shaft, and the conveyance method comprises:
a step of rotating the ball screw shaft by an electric motor;
a step of applying a braking force which is a rotation resistance to the ball screw shaft by a non-electric resistance changing unit;
a step of setting at least one of a driving force of the electric motor and the braking force of the resistance changing unit so that the slider will stop when a predetermined external force acts on the slider during conveyance and changes the slider to an overload state regardless of the presence/absence of the conveyance target object loaded on the slider and a weight of the conveyance target object; and
a step of unidirectionally controlling, by using a one-way rotation transmission mechanism, a transmission direction of a rotation force toward the ball screw shaft by the electric motor when the slider is to move in a vertical direction,
wherein in the step of unidirectionally controlling,
when the balls screw shaft is rotated so as to move the slider in an upward direction, the one-way rotation transmission mechanism cuts off transmission of the rotation force of the electric motor and the braking force of the resistance changing unit, and
when the ball screw shaft is rotated so as to move the slider in a downward direction, the one-way rotation transmission mechanism allows the transmission of the rotation force of the electric motor and the braking force of the resistance changing unit.
2. The conveyance method according to claim 1 , wherein in the step of applying, the resistance changing unit which includes a collar-like disk body, which is fixed to a shaft body coaxially connected to one of the ball screw shaft and the driving shaft, and a pair of magnetic bodies arranged on both sides of the disk body is used to apply the braking force to one of the ball screw shaft and the driving shaft by changing the relative positions of magnetic poles in a circumferential direction of the pair of magnetic bodies to change the magnitude of line of magnetic forces acting on the disk body.
3. The conveyance method according to claim 1 , wherein the external force falls within a range of not less than 50 [N] and not more than 150 [N].
4. A conveyance method of conveying a conveyance target object by loading the conveyance target object on a slider, wherein the slider is connected to a ball nut threadably engaged with a ball screw shaft, and the conveyance method comprises:
a step of rotating the ball screw shaft by an electric motor;
a step of applying a braking force which is a rotation resistance to the ball screw shaft by a non-electric resistance changing unit;
a step of setting at least one of a driving force of the electric motor and the braking force of the resistance changing unit so that the slider will stop when a predetermined external force acts on the slider during conveyance and changes the slider to an overload state regardless of the presence/absence of the conveyance target object loaded on the slider and a weight of the conveyance target object; and
a step of unidirectionally controlling, by using a one-way rotation transmission mechanism, a transmission direction of a rotation force toward the ball screw shaft by the electric motor when the slider is to move in a vertical direction,
wherein in the step of unidirectionally controlling,
when the ball screw shaft is rotated to move the slider in an upward direction, the one-way rotation transmission mechanism cuts off transmission of the rotation force of the electric motor and the braking force of the resistance changing unit, and
when the ball screw shaft is rotated to move the slider in a downward direction and a rotation torque which exceeds a predetermined torque acts on the one-way rotation transmission mechanism, the one-way rotation transmission mechanism allows the transmission of the rotation force of the electric motor and the braking force of the resistance changing unit.
5. A conveyance method of conveying a conveyance target object by loading the conveyance target object on a moved member, wherein the moved member is connected to an endless traveling body to be engaged with a rotated member to be rotated by a driving shaft connected to an electric motor, and the conveyance method comprises:
a step of rotating the driving shaft by the electric motor;
a step of applying a braking force which is a rotation resistance to the driving shaft by a non-electric resistance changing unit; and
a step of setting at least one of a driving force of the electric motor and the braking force of the resistance changing unit so that the moved member will stop when a predetermined external force acts on the moved member during conveyance and changes the moved member to an overload state regardless of the presence/absence of the conveyance target object loaded on the slider and a weight of the conveyance target object; and
a step of unidirectionally controlling, by using a one-way rotation transmission mechanism, a transmission direction of a rotation force toward the driving shaft by the electric motor when the moved member is to move in a vertical direction,
wherein in the step of unidirectionally controlling,
when the rotated member is rotated so as to move the moved member in an upward direction, the one-way rotation transmission mechanism cuts off transmission of the rotation force of the electric motor and the braking force of the resistance changing unit, and
when the rotated member is rotated so as to move the moved member in a downward direction, the one-way rotation transmission mechanism allows the transmission of the rotation force of the electric motor and the braking force of the resistance changing unit.
6. A conveyance method of conveying a conveyance target object by loading the conveyance target object on a moved member, wherein the moved member is connected to an endless traveling body to be engaged with a rotated member to be rotated by a driving shaft connected to an electric motor, and the conveyance method comprises:
a step of rotating the driving shaft by the electric motor;
a step of applying a braking force which is a rotation resistance to the driving shaft by a non-electric resistance changing unit; and
a step of setting at least one of a driving force of the electric motor and the braking force of the resistance changing unit so that the moved member will stop when a predetermined external force acts on the moved member during conveyance and changes the moved member to an overload state regardless of the presence/absence of the conveyance target object loaded on the slider and a weight of the conveyance target object; and
a step of unidirectionally controlling, by using a one-way rotation transmission mechanism, a transmission direction of a rotation force toward the driving shaft by the electric motor when the moved member is to move in a vertical direction,
wherein in the step of unidirectionally controlling,
when the rotated member is rotated to move the moved member in an upward direction, the one-way rotation transmission mechanism cuts off transmission of the rotation force of the electric motor and the braking force of the resistance changing unit, and
when the rotated member is rotated to move the moved member in a downward direction and a rotation torque which exceeds a predetermined torque acts on the one-way rotation transmission mechanism, the one-way rotation transmission mechanism allows the transmission of the rotation force of the electric motor and the braking force of the resistance changing unit.
7. A conveyance method of conveying a conveyance target object by loading the conveyance target object on a slider, wherein the slider is connected to a ball nut threadably engaged with a ball screw shaft, and the conveyance method comprises:
a step of rotating the ball screw shaft by an electric motor;
a step of applying a braking force which is a rotation resistance to the ball screw shaft by a non-electric resistance changing unit; and
a step of adjusting, to stop the slider when an external force having an excessive load which exceeds a predetermined value acts on the slider during conveyance regardless of the presence/absence of the conveyance target object loaded on the slider and a weight of the conveyance target object, the braking force of the resistance changing unit, and setting a difference between a driving force of the electric motor and the predetermined external force to be not more than a sum of the weight of the conveyance target object, a weight of the slider, and the braking force of the resistance changing unit.
8. The conveyance method according to claim 7 , wherein in the step of setting, the driving force of the electric motor is further adjusted.
9. A conveyance method of conveying a conveyance target object by loading the conveyance target object on a moved member, wherein the moved member is connected to an endless traveling body to be engaged with a rotated member to be rotated by a driving shaft connected to an electric motor, and the conveyance method comprises:
a step of rotating the driving shaft by the electric motor;
a step of applying a braking force which is a rotation resistance to the driving shaft by a non-electric resistance changing unit; and
a step of adjusting, to stop the moved member when an external force having an excessive load which exceeds a predetermined value acts on the moved member during conveyance regardless of the presence/absence of the conveyance target object loaded on the moved member and a weight of the conveyance target object, the braking force of the resistance changing unit, and setting a difference between a driving force of the electric motor and the external force to be not more than a sum of the weight of the conveyance target object, a weight of the moved member, and the braking force of the resistance changing unit.
10. The conveyance method according to claim 9 , wherein in the step of setting, the driving force of the electric motor is further adjusted.
11. The conveyance method according to claim 9 , wherein in the step of setting, the driving force of the electric motor is fixed, and only the braking force of the resistance changing unit can be changed.
12. A conveyance apparatus comprising:
an electric motor;
a ball screw shaft to be connected to the electric motor;
a ball nut to be threadably engaged with the ball screw shaft;
a moved member to be connected to the ball nut, loaded with a conveyance target object, and moved in a vertical direction;
a non-electric resistance changing unit to be connected to the ball screw shaft and configured to apply, to the ball screw shaft, a braking force which is a rotation resistance to the ball screw shaft and to be capable of adjusting the braking force; and
a one-way rotation transmission mechanism configured to unidirectionally control a transmission direction of a rotation force toward the ball screw shaft by the electric motor,
wherein when the ball screw shaft is to be rotated in one direction, the one-way rotation transmission mechanism runs idly to cut off transmission of the rotation force of the electric motor and the braking force of the resistance changing unit, and
when the ball screw shaft is to be rotated in the other direction, the one-way rotation transmission mechanism is rotated to allow the transmission of the rotation force of the electric motor and the braking force of the resistance changing unit.
13. The conveyance apparatus according to claim 12 , wherein when one of the ball screw shaft and the rotated member is rotated in the other direction and a rotation torque which exceeds a predetermined torque acts on the one-way rotation transmission mechanism, the one-way rotation transmission mechanism allows the transmission of the rotation force of the electric motor and the braking force of the resistance changing unit.
14. The conveyance apparatus according to claim 12 , wherein the resistance changing unit is a non-contact torque control apparatus.
15. The conveyance apparatus according to claim 14 , wherein the non-contact torque control apparatus includes
a collar-like disk body fixed to a shaft body coaxially connected to one of the ball screw shaft and the driving shaft and a pair of magnetic bodies arranged on both sides of the disk body, and
applies the braking force to one of the ball screw shaft and the driving shaft by changing relative positions of magnetic poles in a circumferential direction of the pair of magnetic bodies to change the magnitude of lines of magnetic forces acting on the disk body.
16. The conveyance apparatus according to claim 12 , wherein one of the force of the electric motor and the braking force of the resistance changing unit is adjusted so as to stop the moved member when a predetermined external force acts on the moved member during the conveyance and the moved member changes to an overload state, and
the predetermined external force falls within a range of not less than 50 [N] and not more than 150 [N].
17. A conveyance apparatus comprising:
an electric motor;
a driving shaft to be connected to the electric motor;
a rotated member to be rotated by the driving shaft;
an endless traveling body to be engaged with the rotated member;
a moved member to be connected to the endless traveling body, loaded with a conveyance target object, and move in a vertical direction;
a non-electric resistance changing unit to be connected to the driving shaft and configured to apply, to the driving shaft, a braking force which is a rotation resistance to the ball screw and to be capable of adjusting the braking force; and
a one-way rotation transmission mechanism configured to unidirectionally control a transmission direction of a rotation force toward the driving shaft by the electric motor,
wherein when the rotated member is to be rotated in one direction, the one-way rotation transmission mechanism runs idly to cut off transmission of the rotation force of the electric motor and the braking force of the resistance changing unit, and
when the rotated member is to be rotated in the other direction, the one-way rotation transmission mechanism is rotated to allow the transmission of the rotation force of the electric motor and the braking force of the resistance changing unit.
18. A conveyance apparatus comprising:
an electric motor;
a ball screw shaft to be connected to the electric motor;
a ball nut to be threadably engaged with the ball screw shaft;
a moved member to be connected to the ball nut and loaded with a conveyance target object; and
a non-electric resistance changing unit to be connected to the ball screw shaft and configured to apply, to the ball screw shaft, a braking force which is a rotation resistance to the ball screw shaft and to be capable of adjusting the braking force,
wherein to stop the moved member when an external force having an excessive load which exceeds a predetermined value acts on the moved member during conveyance regardless of the presence/absence of the conveyance target object loaded on the moved member and a weight of the conveyance target object, the braking force of the resistance changing unit is adjusted so a difference between a driving force of the electric motor and the external force will not be more than a sum of the weight of the conveyance target object, a weight of the moved member, and the braking force of the resistance changing unit.
19. The conveyance apparatus according to claim 18 , wherein the driving force of the electric motor is further adjusted so the difference between the driving force of the electric motor and the external force will not be more than the sum of the weight of the conveyance target object, the weight of the moved member, and the braking force of the resistance changing unit.
20. A conveyance apparatus comprising:
an electric motor;
a driving shaft to be connected to the electric motor;
a rotated member to be rotated by the driving shaft;
an endless traveling body to be engaged with the rotated member;
a moved member to be connected to the endless traveling body and loaded with a conveyance target object; and
a non-electric resistance changing unit to be connected to the driving shaft and configured to apply a braking force, to the driving shaft, which is a rotation resistance to the ball screw shaft and to be capable of adjusting the braking force,
wherein to stop the moved member when an external force having an excessive load which exceeds a predetermined value acts on the moved member during conveyance regardless of the presence/absence of the conveyance target object loaded on the moved member and a weight of the conveyance target object, the braking force of the resistance changing unit is adjusted so a difference between a driving force of the electric motor and the external force will not be more than a sum of the weight of the conveyance target object, a weight of the moved member, and the braking force of the resistance changing unit.
21. The conveyance apparatus according to claim 20 , wherein the driving force of the electric motor is further adjusted so the difference between the driving force of the electric motor and the external force will not be more than the sum of the weight of the conveyance target object, the weight of the moved member, and the braking force of the resistance changing unit.