Press brake

Patent metadata

Field	Value
Publication number	US-10919248-B2
Application number	US-201716343693-A
Country	US
Kind code	B2
Filing date	Sep 28, 2017
Priority date	Oct 27, 2016
Publication date	Feb 16, 2021
Grant date	Feb 16, 2021

Abstract

A press brake includes a ram to which an upper or lower tool can be attached; a movable ram driver; and a controller that controls the ram driver, wherein the ram driver includes a rotation/linear motion converter composed of a screw fixed to the ram and moves upward and downward as the ram moves upward and downward, and a nut screw-coupled with the screw; a drive rotation body arranged rotatably about a rotation axis of the nut; a first motor arranged in a fixed state; a first power transmitter that transmits rotation of the first motor to the nut at high speed and with low torque; a second motor arranged in a fixed state; a second power transmitter that transmits rotation of the second motor to the drive rotation body at low speed and with high torque; and a clutch provided between the nut and the drive rotation body.

First claim

The invention claimed is:

1. A press brake that performs bending work on a workpiece by holding the workpiece between an upper tool and a lower tool, the press brake comprising:
a ram to which the upper tool or the lower tool can be attached;
a ram driver that moves the ram upward and downward; and
a controller that controls the ram driver, wherein the ram driver includes:
a rotation/linear motion converter composed of a screw fixed to the ram and moves upward and downward as the ram moves upward and downward, and a nut screw-coupled with the screw;
a drive rotation body arranged apart from the nut in an axial direction of the screw and arranged rotatably about a rotation axis of the nut;
a first motor arranged in a fixed state;
a first power transmitter that transmits rotation of the first motor to the nut at high speed and with low torque;
a second motor arranged in a fixed state;
a second power transmitter that transmits rotation of the second motor to the drive rotation body at low speed and with high torque; and
a clutch provided between the nut and the drive rotation body and that couples the nut and the drive rotation body into an integrated rotation body.

2. The press brake according to claim 1 , wherein
the controller includes a synchronous rotation controller that controls the first motor so that the upper tool or the lower tool descends within a range that includes at least a part of an approaching-workpiece stroke among strokes including the approaching-workpiece stroke, a contacting-workpiece stroke, and an ending-bending-work stroke, and
matches a rotation speed of the nut being rotated by the first motor with a rotation speed of the drive rotation body being rotated by the second motor, during the approaching-workpiece stroke to couple the nut and the drive rotation body by the clutch after the synchronous rotation controller has matched the rotation speed of the nut with the rotation speed of the drive rotation body.

3. The press brake according to claim 2 , wherein the synchronous rotation controller controls the first motor so that the rotation speed of the nut is reduced to the rotation speed of the drive rotation body being rotated or scheduled to be rotated at low speed by the second motor.

4. The press brake according to claim 1 , wherein the drive rotation body has an accommodating part that accommodates at least a part of the nut; an outer circumferential part thereof is a power receiver that receives power transmitted from the second power transmitter; and an inner circumferential part thereof is opposed to a part of an outer circumferential part of the nut via a bearing, and
the drive rotation body is rotatably supported in an axial direction thereof via a reaction force receiver held on a frame arranged in a fixed state.

5. The press brake according to claim 1 , wherein the controller has a use/non-use selector that selects between use and non-use of the clutch.

6. The press brake according to claim 1 , wherein the clutch couples the nut and the drive rotation body by reaction force generated when work is performed on a workpiece.

7. The press brake according to claim 1 , wherein the clutch includes a driver that moves at least one of the nut and the drive rotation body, which are apart from each other, to couple the nut and the drive rotation body.

8. A press brake that performs bending work on a workpiece by holding the workpiece between an upper tool and a lower tool, the press brake comprising:
a ram to which the upper tool or the lower tool can be attached;
a frame installed on a floor surface and that guides the ram in a vertical direction;
a ram driver that moves the ram upward and downward; and
a controller that controls the ram driver, wherein the ram driver includes:
a rotation/linear motion converter composed of a screw and a nut screw-coupled with the screw, one of the screw and the nut is fixed to the ram, and the other one of the screw and the nut is fixed to the frame;
a first motor fixed to the ram or the frame;
a second motor fixed to the ram or the frame, to which the first motor is fixed;
a drive rotation body arranged apart in an axial direction of the screw from the nut or the screw rotated by the first motor while being able to rotate about a rotation axis of the nut or the screw, and is rotated by the second motor; and
a clutch provided between the nut or the screw rotated by the first motor and the drive rotation body, and couples the nut or the screw and the drive rotation body into an integrated rotation body.

9. The press brake according to claim 2 , wherein
the drive rotation body has an accommodating part that accommodates at least a part of the nut; an outer circumferential part thereof is a power receiver that receives power transmitted from the second power transmitter; and an inner circumferential part thereof is opposed to a part of an outer circumferential part of the nut via a bearing, and
the drive rotation body is rotatably supported in an axial direction thereof via a reaction force receiver held on a frame arranged in a fixed state.

10. The press brake according to claim 3 , wherein
the drive rotation body has an accommodating part that accommodates at least a part of the nut; an outer circumferential part thereof is a power receiver that receives power transmitted from the second power transmitter; and an inner circumferential part thereof is opposed to a part of an outer circumferential part of the nut via a bearing, and
the drive rotation body is rotatably supported in an axial direction thereof via a reaction force receiver held on a frame arranged in a fixed state.

11. The press brake according to claim 2 , wherein the clutch couples the nut and the drive rotation body by reaction force generated when work is performed on a workpiece.

12. The press brake according to claim 3 , wherein the clutch couples the nut and the drive rotation body by reaction force generated when work is performed on a workpiece.

13. The press brake according to claim 4 , wherein the clutch couples the nut and the drive rotation body by reaction force generated when work is performed on a workpiece.

14. The press brake according to claim 5 , wherein the clutch couples the nut and the drive rotation body by reaction force generated when work is performed on a workpiece.

15. The press brake according to claim 2 , wherein the clutch includes a driver that moves at least one of the nut and the drive rotation body, which are apart from each other, to couple the nut and the drive rotation body.

16. The press brake according to claim 3 , wherein the clutch includes a driver that moves at least one of the nut and the drive rotation body, which are apart from each other, to couple the nut and the drive rotation body.

17. The press brake according to claim 4 , wherein the clutch includes a driver that moves at least one of the nut and the drive rotation body, which are apart from each other, to couple the nut and the drive rotation body.

18. The press brake according to claim 5 , wherein the clutch includes a driver that moves at least one of the nut and the drive rotation body, which are apart from each other, to couple the nut and the drive rotation body.

Assignees

• Murata Machinery Ltd

Inventors

• Hattori Katsumasa

Classifications

• B30B1/18

  by screw means {(B30B9/3064 takes precedence)} · CPC title

• B21D5/02

  on press brakes without making use of clamping means · CPC title

• B30B15/142

  controlling the brake or the clutch · CPC title

• B30B1/186 Primary

  Control arrangements · CPC title

• F16H2025/2081

  Parallel arrangement of drive motor to screw axis · CPC title