CN215316435U

CN215316435U - Clamping device and machine tool with such a clamping device

Info

Publication number: CN215316435U
Application number: CN202120515922.1U
Authority: CN
Inventors: T·波普
Original assignee: Trumpf Werkzeugmaschinen SE and Co KG
Current assignee: Trumpf Werkzeugmaschinen SE and Co KG
Priority date: 2020-03-11
Filing date: 2021-03-11
Publication date: 2021-12-28
Anticipated expiration: 2031-03-11
Also published as: DE202020101344U1

Abstract

The utility model relates to a clamping device (510) for clamping a pipe (550) or a profile being machined on a machine tool (548), having a non-rotatable part (530) and a rotatable part (512) for clamping the pipe (550) or the profile, wherein the rotatable part (512) has: a) chuck plate(514) -the chuck has a first clamp (516) and a second clamp (518) for clamping the pipe (550) or profile; b) a first cylinder (526a) in the form of a pneumatic cylinder for tensioning the first clamp (516), wherein the first cylinder (526a) has a first chamber (532) and a second chamber (534) which can be loaded with a first pressure (p) via a first pneumatic line (A) and a second pneumatic line (B) independently of one another₁) And a second pressure (p)₂). The utility model also relates to a machine tool having such a clamping device.

Description

Clamping device and machine tool with such a clamping device

Technical Field

The utility model relates to a clamping device for clamping a pipe or profile which is to be machined on a machine tool, wherein the clamping device has a non-rotatable part and a rotatable part for clamping the pipe or profile, wherein the rotatable part has:

a) a chuck having a first clamp and a second clamp for clamping a pipe or profile;

b) a first cylinder in the form of a pneumatic cylinder for tensioning the first clamp.

The utility model also relates to a machine tool having such a clamping device.

Background

It is known that machine tools are provided with clamping devices for clamping pipes or profiles to be machined on the machine tool. In order to be able to achieve a rapid, automated clamping, at least one clamp of the chuck can be moved by means of a first cylinder in the form of a pneumatic cylinder or a hydraulic cylinder. It has been shown that damage can occur when clamping pipes or profiles which can only withstand small clamping forces.

SUMMERY OF THE UTILITY MODEL

It is therefore the object of the present invention to provide a clamping device for clamping a pipe or profile being machined on a machine tool, said clamping device having a non-rotatable part and a rotatable part for clamping the pipe or profile, wherein the rotatable part has:

a) a chuck having a first clamp and a second clamp for clamping the pipe or profile;

b) a first cylinder in the form of a pneumatic cylinder for tensioning the first clamp;

wherein the first cylinder has a first chamber and a second chamber which can be loaded with a first pressure and a second pressure independently of one another via a first pneumatic line and a second pneumatic line,

the clamping device can realize the nondestructive clamping of the pipe fitting or the section bar. The object of the utility model is, furthermore, to provide a machine tool having such a clamping device.

According to the utility model, this object is achieved by the clamping device described at the outset. Furthermore, the object is achieved by a machine tool having such a clamping device. Advantageous embodiments are given below.

The object of the utility model is therefore achieved by a clamping device for clamping a pipe or profile to be machined on a machine tool, wherein the clamping device has a non-rotatable part and a rotatable part for clamping the pipe or profile, wherein the rotatable part has:

wherein the first cylinder has a first chamber and a second chamber which can be loaded with a first pressure and a second pressure independently of one another by means of a first pneumatic line and a second pneumatic line.

Pneumatic cylinders relate to double acting cylinders. By independently loading the two chambers with the first pressure or the second pressure, the clamping force exerted on the pipe or profile during clamping can be precisely adjusted.

For clamping the pipe or profile, the first chamber of the pneumatic cylinder may be loaded with a first pressure in order to apply a clamping force to the first clamp. The first pressure supplied to the first chamber of the pneumatic cylinder via the first pneumatic line and acting on the piston face can generally be continuously adjusted or regulated over a wide pressure range (e.g. about 2bar to about 10bar) in order to generate a clamping force that is adapted to the workpiece parameters (e.g. pipe thickness, pipe diameter, material). In order to adjust the pressure in the first chamber, which pressure is adapted to the respective pipe or profile to be clamped, and thus to adjust the corresponding clamping force, the machine tool can access workpiece parameters, which are stored, for example, in a table or the like.

It has been shown that, despite the regulation or adjustment of the pressure in the first chamber of the pneumatic cylinder, damage to the pipe or profile during clamping is still possible, since the pressure in the first chamber should not be below a minimum pressure (e.g. about 2 bar): below this minimum pressure, reliable switching of the valve through which the gaseous medium, generally compressed air, flows is no longer ensured.

In case the pipe or profile is not able to withstand the clamping force generated by the minimum pressure in the first chamber, a counter pressure is generated by loading the second chamber with the second pressure, which counter pressure acts on the piston ring surface in order to reduce the clamping force applied to the pipe or profile by the clamp.

The difference between the first pressure and the second pressure determines the clamping force with which the pipe or profile is clamped. For a gentle clamping of the pipe or profile, a pressure difference below the minimum pressure can be set.

Preferably, the clamping device has a valve assembly controllable via the third pneumatic line for jointly releasing or blocking the first and second pneumatic lines. The third pneumatic line serves as a control line for the pilot valve assembly. In the blocking state, the valve assembly simultaneously blocks both pneumatic lines in order to maintain the pressure in both chambers of the pneumatic cylinder and thus the clamping force. In the released state, the chuck may be opened or closed depending on the pressure in each chamber.

In one embodiment, the valve assembly has a first and a second directional control valve which can be controlled via a third pneumatic line. The first reversing valve is used for releasing or stopping the first pneumatic pipeline. The second reversing valve is used for releasing or stopping the second pneumatic pipeline. The two directional valves are switched synchronously by the pressure in the third pneumatic line and act as stop valves.

Preferably, the valve assembly has a throttling check valve. The throttle check valve serves to throttle the outflow compressed air, for example from the second chamber, while the compressed air flowing into the second chamber flows through the throttle check valve in the throughflow direction without being throttled. In this way, when the chuck is closed, the movement of the piston is inhibited, and when the chuck is open, the piston performs an uninhibited movement.

Preferably, the valve assembly is integrated into the first cylinder. The first cylinder has in this case three pneumatic connections for the first, second and third pneumatic lines. The throttle check valve may be arranged on the outside of the cylinder and the first and second directional valves may be integrated into the bottom of the pneumatic cylinder, for example.

In one embodiment, the chuck comprises a three-way rotary connection for connecting each section of the first, second and third pneumatic lines in the non-rotatable part of the clamping device with each section of the first, second and third pneumatic lines in the rotatable part of the clamping device. This enables the clamping force to be adjusted starting from the non-rotatable part of the clamping device.

In a further embodiment, the clamping device has a controllable pressure regulating valve for regulating the first pressure in the first pneumatic line and/or the second pressure in the second pneumatic line. The pressure regulating valve is usually electrically actuatable and can be arranged in particular in a non-rotatable part of the clamping device. By means of the pressure regulating valve, the first/second pressure can be adjusted or regulated steplessly in a large pressure range, for example in the pressure range of 2 to 10 bar. It is sufficient if the pressure in one of the two pneumatic lines is adjustable. When the respective switching valve is open, the respective other pneumatic line can be supplied with a constant pressure, for example a pressure of about 5 bar.

Preferably, the clamping device has a second cylinder in the form of a pneumatic cylinder for tensioning the second clamp. The second cylinder is preferably constructed identically to the first cylinder structure. In particular, the second cylinder may comprise a valve assembly configured identically to the valve assembly of the first cylinder.

In order to ensure a simultaneous movement of the first and second jaws, the movement of the first jaw can be mechanically coupled with the movement of the second jaw by means of a first coupling device, so that the clamping movement of the first and second jaws takes place synchronously and the pipe or profile is clamped centrally.

In one variant of the first coupling device, the first coupling device has a first ring segment with attachment points for a first and a second clamp.

In a further preferred embodiment of the utility model, the clamping device has a third clamp and a third cylinder in the form of a pneumatic cylinder for tensioning the third clamp.

The clamping device may have a fourth clamp and a fourth cylinder in the form of a fourth pneumatic cylinder for tensioning the fourth clamp. The grippers can be arranged and actuated in pairs, respectively. Preferably, the first and second gripper jaws form a first gripper jaw pair and the third and fourth gripper jaws form a second gripper jaw pair.

The third gripper jaw can be coupled to the movement of the fourth gripper jaw by means of a second coupling device, so that the clamping movements of the third gripper jaw and the fourth gripper jaw are synchronized.

The second coupling device may be structurally identical to the first coupling device. The second coupling device may have a second ring segment having attachment points for the third and fourth clamps.

Preferably, the pneumatic cylinders of the clamping device are arranged and/or constructed axisymmetrically with respect to the longitudinal axis, i.e. the rotational axis of the rotatable part of the clamping device. Alternatively or additionally, the pneumatic cylinders of the clamping device are preferably of identical design.

The clamping device can be designed to hold the pipe or profile in an axially immovable manner. Alternatively, the chuck can be designed as a push-in chuck (durchchiebefetter), wherein the jaws each have a roller at their free ends in order to be able to move the pipe or profile axially in the chuck.

The object is also achieved by a machine tool having a tool for machining pipes or profiles, wherein the machine tool has at least one clamping device which is designed as described above.

The machine tool may have a clamping device in the region of the tool, which clamping device is designed as a push-in chuck.

The machine tool may also have a feed station that is movable in the axial direction, wherein the feed station has a (further) clamping device in which the pipe or profile is held immovably in the axial direction.

The tool may be configured in the form of a laser machining tool.

The mechanical guiding means of the clamp, in particular the first and/or second coupling means, may be constructed according to CN 207521898U, CN 207521891U, CN 207521729U, CN 206677411U and/or CN 107790904 a, the contents of which (by reference) are fully incorporated in the present application.

Drawings

Further advantages of the utility model result from the description and the drawings. The features mentioned above and those yet further listed can likewise be used individually or in any combination of a plurality of them. The embodiments shown and described are not to be understood as being exhaustive in the end, but rather as having exemplary features for describing the utility model.

FIG. 1 shows an isometric view of a rotatable portion of a chuck having four jaws;

fig. 2 shows a top view of the clamping device according to fig. 1 without four clamping jaws;

FIG. 3 shows a pneumatic circuit diagram of the clamping device of FIG. 1;

fig. 4 shows a machine tool for machining pipes or profiles which can be held by two clamping devices, wherein one clamping device is configured as in fig. 1.

Detailed Description

Fig. 1 shows a clamping device 510, more precisely a rotatable part 512 of the clamping device 510. The rotatable part 512 comprises a chuck 514. The chuck 514 includes a first clamp 516, a second clamp 518, a third clamp 520, and a fourth clamp 522. The first clamp 516 is preferably opposed to the second clamp 518. The third jaw 520 is preferably opposed to the fourth jaw 522. The

clamps

516, 518, 520, 522 each have a roller 524a-d at their free ends. The chuck 514 is thus designed as a push-in chuck, wherein the pipe or profile is held immovably in the radial direction but movably in the axial direction.

The first clamp 516 is coupled to the second clamp 518 by a mechanical first coupling means. The third clamp 520 is coupled to the fourth clamp 522 by a second mechanical coupling. Thus, the

clamps

516, 518, 520, 522 are forcibly coupled in pairs, respectively, to enable a centered clamping of the chuck 514. The mechanical coupling of the

clamps

516, 518, 520, 522 is described in particular in CN 207521898U, the content of which is fully incorporated in the present description.

Fig. 2 shows a top view of the clamping device 510 according to fig. 1, wherein the illustration of the clamping

jaws

516, 518, 520, 522 is omitted. As can be seen in fig. 2, the first clamp 516 can be moved by means of a first cylinder 526a, here in the form of a pneumatic cylinder. A second cylinder 526b, also in the form of a pneumatic cylinder, is used to move the second clamp 518, a third cylinder 526c, also in the form of a pneumatic cylinder, is used to move the third clamp 520, and a fourth cylinder 526d, also configured as a pneumatic cylinder, is used to move the fourth clamp 522. The second cylinder 526b and the fourth cylinder 526d are arranged axisymmetrically to the first cylinder 526a and the third cylinder 526c, respectively, with respect to a longitudinal axis 528 of the clamping device 510. The longitudinal axis 528 is located at the center of the gripping device 510.

Fig. 3 shows a pneumatic circuit diagram of a clamping device 510 having first through fourth pneumatic cylinders 526 a-d. Each of the four pneumatic cylinders 526a-d has first, second and third connections for first, second and third pneumatic lines A, B, C. The four pneumatic cylinders 526a-d are identical in construction. The structure of the first pneumatic cylinder 526a configured as a double-acting cylinder is exemplarily described below.

The first pneumatic cylinder 526a has a first 532 and a second 534 chamber which can be loaded independently of one another with a first pressure p₁And a second pressure p₂. First pressure p in first chamber 532₁Acting on the piston face of the piston rod of the first cylinder 526 a. Second pressure p in second chamber 532₂Acting on the piston ring surface of the piston rod and generating a pressure p in the first chamber 530₁The forces generated are in opposite directions.

The first pneumatic line a is used to supply compressed air to or lead out of the first chamber 532. The second pneumatic line B is used to supply compressed air to or lead out of the second chamber 534. The valve assembly 536 is integrated into the first pneumatic cylinder 526 a. The valve assembly 536 has a first direction valve 538 with two switching states. In the first switching state, the first pneumatic line a is blocked, and in the second switching state, the first pneumatic line a is released to allow the compressed air to flow therethrough. The valve assembly 536 has a second reversing valve 540 with two switching states. In the first switching state, the second pneumatic line B is blocked and in the second switching state, the second pneumatic line B is released to let the compressed air flow through.

The two switching states of the valve assembly 536, more precisely the first direction changing valve 538 and the second direction changing valve 540, can beCan be synchronously controlled by the third pneumatic line C. At constant control pressure p without loading₃(e.g., about 9-10bar), the two directional valves 538, 540 occupy a blocked switching state such that the first pressure p in the first chamber 532 is maintained₁And a second pressure p in the second chamber 534₂Unchanged in order to maintain the clamping force for clamping the pipe or profile.

For clamping the pipe or profile, the two directional control valves 538, 540 are acted upon by the pressure p in the third pneumatic line C₃Is switched into the open switching state. First pressure p in first pneumatic line a₁Can be adjusted by means of an electrically actuable pressure control valve 544, for example, in a pressure range of 2 to 10 bar. If it is ensured that when the piston rod of the first pneumatic cylinder 526a is loaded with a first pressure p greater than about 2bar₁If the pipe or profile is not damaged during the clamping, the application of a counterforce to the piston rod can be dispensed with, i.e. the second pneumatic line B is switched to pressureless by means of a non-illustrated switching valve. When clamping a pipe or profile, the movement of the piston rod of the first pneumatic cylinder 526a is damped by means of a throttle check valve 542 arranged in the second pneumatic line B between the second chamber 534 and the second directional valve 540.

When clamping a pipe or profile with the clamping device 510 (which pipe or profile is under an adjustable minimum first pressure p of about 2bar)₁Lower damage), the second chamber 534 is loaded with a constant second pressure p, for example 5bar, by the second pneumatic line B₂. Here, the first chamber 532 is loaded with a pressure greater than the second pressure p₂First pressure p of₁. First pressure p₁By means of an electrically controllable pressure regulating valve 544, it is adjusted depending on the workpiece parameters of the pipe or profile to be clamped. First pressure p in first chamber 532₁And a second pressure p in the second chamber 534₂The difference between (taking into account the piston face geometry of the piston rod) determines the clamping force applied by the chuck 514 to the pipe or profile.

To open the chuck 514, the further reversing valve 546 in the first pneumatic line a is placed in a switching state in which compressed air can escape from the first chamber 532. Compressed air flows into the second chamber 534 via the throttling check valve 542 and the piston rod moves into the retracted position shown in fig. 3.

The three-way rotary connection 547 is used to connect the sections of the first, second and third pneumatic lines A, B, C in the non-rotatable portion 530 of the clamping device 510 with the sections of the first, second and third pneumatic lines A, B, C in the rotatable portion 512 of the clamping device 510. An electronically controllable pressure regulating valve 544 and a further reversing valve in the first pneumatic line a are arranged in the non-rotatable part 530 of the clamping device 510. For clarity, the valve members in the second and third pneumatic lines B, C are omitted from the non-rotatable portion 530.

Fig. 4 shows a machine tool 548 for machining a pipe 550 or a profile, which is shown in chain line. The tubular 550 is held by the gripping device 510 and another gripping device 552. The further gripping device 552 is structurally identical to the gripping device 510, but does not have rollers 524a-d, so that the tube 550 is held axially immovably by the further gripping device 552. The further clamping device 552 is arranged at an axially movable feed station 554. For machining the pipe 550, the machine tool 548 has a tool 556, here in the form of a laser machining tool.

The further clamping device 552 need not necessarily be configured like the clamping device 510. For example, the third pneumatic line C or the independent application of different pressures p to the two chambers 532, 534 of the pneumatic cylinders 526a-d can be omitted in the further clamping device 552₁、p₂。

The gripping device 510 or machine tool 558 has been described in terms of cylinders 526a-d in the form of pneumatic cylinders. However, both the clamping device 510 and the machine tool 558 can also be operated via corresponding hydraulic lines with cylinders in the form of hydraulic cylinders.

List of reference numerals

510 a clamping device;

512 a rotatable part of the clamping device;

514 a chuck;

516 a first clamp;

518 second clamp;

520 a third clamp;

522 a fourth jaw;

524a-d rollers;

526a-d first through fourth cylinders;

527 clamping the longitudinal axis of the device;

530 non-rotatable part of the clamping device;

532 a first chamber;

534 a second chamber;

536 a valve assembly;

538 a first direction valve;

540 a second direction valve;

542 a throttle check valve;

544 controllable pressure regulating valve;

546 another direction valve;

547 three-way rotary connector;

548 machine tool;

550 pipe fittings;

552 another clamping device;

554 a feed station;

556 tool;

a, a first pneumatic pipeline;

b, a second pneumatic pipeline;

c, a third pneumatic pipeline;

p₁a first pressure;

p₂a second pressure;

p₃third pressure

Claims

1. A clamping device (510) for clamping a pipe (550) or a profile being machined on a machine tool (548), characterized in that the clamping device has a non-rotatable part (530) and a rotatable part (512) for clamping the pipe (550) or the profile, wherein the rotatable part (512) has:

a) a chuck (514) having a first clamp (516) and a second clamp (518) for clamping the pipe (550) or profile;

b) a first cylinder (526a) in the form of a pneumatic cylinder for tensioning the first clamp (516);

wherein the first cylinder (526a) has a first chamber (532) and a second chamber (534) which can be loaded with a first pressure (p) via a first pneumatic line (A) and a second pneumatic line (B) independently of one another₁) And a second pressure (p)₂)。

2. Clamping device according to claim 1, having a valve assembly (536) controllable by a third pneumatic line (C) for jointly releasing or blocking the first and second pneumatic lines (a, B).

3. The clamping device as claimed in claim 2, wherein the valve assembly (536) has a first direction valve (538) and a second direction valve (540) controllable via the third pneumatic line (C).

4. The clamping device as claimed in claim 2 or 3, wherein the valve assembly (536) has a throttling check valve (542).

5. The clamping device as claimed in claim 2 or 3, wherein the valve assembly (536) is integrated into the first cylinder (526 a).

6. Clamping device according to claim 2 or 3, comprising a three-way rotary connection (547) for connecting sections of the first, second and third pneumatic lines (A, B, C) in a non-rotatable part (530) of the clamping device (510) with sections of the first, second and third pneumatic lines (A, B, C) in a rotatable part (512) of the clamping device (510).

7. Clamping device according to one of claims 1 to 3, having a controllable pressure regulating valve (544) for regulating a first pressure (p) in the first pneumatic line (A)₁) And/or a second pressure (p) in the second pneumatic line (B)₂)。

8. The clamping device as claimed in one of claims 1 to 3, wherein the clamping device (510) has a second cylinder (526b) in the form of a pneumatic cylinder for tensioning the second clamp (518).

9. The clamping device as recited in claim 8, wherein the second cylinder (526b) is structurally identically configured to the first cylinder (526 a).

10. The clamping device as claimed in one of claims 1 to 3 and 9, wherein a movement of the first clamp (516) is coupled with a movement of the second clamp (518) by means of a first coupling device, such that the clamping movements of the first clamp (516) and the second clamp (518) take place synchronously.

11. The clamping device as recited in claim 10, wherein the first coupling device has a first ring segment with attachment points for the first clamp (516) and the second clamp (518).

12. The clamping device as claimed in one of claims 1 to 3, 9 and 11, wherein the clamping device (510) has a third clamp (520) and a third cylinder (526c) in the form of a pneumatic cylinder for tensioning the third clamp (520).

13. The clamping device as claimed in claim 12, wherein the clamping device (510) has a fourth clamp (522) and a fourth cylinder (526d) in the form of a pneumatic cylinder for tensioning the fourth clamp (522).

14. The clamping device according to claim 13, wherein the movement of the third clamp (520) is coupled with the movement of the fourth clamp (522) by a second coupling device such that the clamping movements of the third clamp (520) and the fourth clamp (522) are synchronized.

15. The clamping device as recited in claim 14, wherein the second coupling device has a second ring segment with attachment points for the third and fourth clamps (520, 522).

16. Clamping device according to one of claims 1 to 3, 9, 11, 14 and 15, wherein the jaws (516, 518, 520, 522) each have one roller (524a-d) at their free ends in order to be able to move the tube (550) or profile axially in the chuck (514).

17. A machine tool (548) having a tool (556) for machining a pipe (550) or a profile, wherein the machine tool (548) has at least one clamping device (510) according to any one of claims 1 to 16.

18. Machine tool according to claim 17, having a clamping device (510) according to claim 16 in the region of the tool (556).

19. A machine tool according to claim 17 or 18, having an axially movable feed station (554), wherein the feed station (554) has a further clamping device (552) which is configured according to one of claims 1 to 15.

20. A machine tool according to claim 17 or 18, wherein the tool (556) is configured in the form of a laser machining tool.