Laser tool and method for adjusting the focal position of a laser

Abstract

In order to provide a laser tool (100), in particular for forming a working surface of a cylinder, which provides the feasibility of guiding a laser beam (10a) of the laser tool (100) in a process-reliable manner, it is proposed that the laser tool (100) has a laser source (10) for generating the laser beam (10a), which is guided through a lens tube (18) located in a hollow shaft (20), wherein a lens (12) is fastened in the lens tube (18), through which a laser beam (10a) is guided, and wherein the hollow shaft (20) is rotatably designed as a hollow shaft motor (19), and wherein a spindle (13) is fastened to the hollow shaft (20), on which spindle an optical device for deflecting the laser beam (10a) onto a workpiece surface is fastened, the hollow shaft (20) is rotatable independently of the lens (12).

Description

[0001] This application is a divisional application of the invention application filed on September 14, 2017, with application number 201780081768.8 and entitled "Laser tool having a hollow shaft drive device and a non-rotating lens; method for adjusting the focal position of a laser beam in a laser tool".

[0002] The present invention relates to a laser tool, particularly for constructing or structuring the working surface of a cylinder, the laser tool having a fixed lens and a lead screw or shaft driven by a hollow shaft drive device that can rotate independently of the lens. The present invention also relates to a method for adjusting the focal position of a laser beam in the laser tool. Existing technology

[0003] Laser tools are used in the field of automotive technology for machining and constructing workpiece surfaces. In particular, laser tools are used to machine fine structures on the working surfaces or running surfaces of cylinders. In laser tools known in the prior art, a laser beam generated in a laser source is guided to the workpiece surface by sequentially arranged optical elements, wherein the laser beam is rotated by a rotatable device. Here, the correct position of the laser beam focal point is crucial for optimal machining results; this position should be adjusted and formed as accurately as possible and reproducibly. The guidance of the laser beam in the optical elements of the laser tool influences the focal point position, and these optical elements should be positioned as accurately as possible in the optical path. It is particularly advantageous that the optical components can move independently of the lead screw.

[0004] A laser tool for precision machining the inner surface of workpiece holes, particularly the working surface of cylinders, is known from patent document DE 10 2008 015 403 A1. This laser tool is mounted on a rotatable, and particularly height- and height-adjustable, hollow machine tool spindle. An optical device for deflecting the laser beam onto the workpiece surface is adjustable relative to the machine tool spindle, allowing the laser beam to move independently of the spindle's motion. Specifically, it is specified that a rotational motion of the optical device, opposite to the rotational motion of the machine tool spindle, can be superimposed using an adjustment device. This extends the interaction time between the laser beam and the workpiece surface, enabling the machining of free-form structures.

[0005] Summary of the Invention: Technical Problem, Solution, Advantages

[0006] The technical problem to be solved by the present invention is to provide a laser tool that provides the feasibility of reliably guiding the laser beam of the laser tool in a process. This technical problem is solved by an apparatus having the features of claim 1 and a method having the features of claim 11.

[0007] The present invention provides a laser tool, particularly for constructing the working surface of a cylinder, having a laser source for generating a laser beam, the laser beam being guided through a lens tube located in a hollow shaft, wherein the lens is fixed in the lens tube and the laser beam is guided through the lens, wherein the hollow shaft is rotatably designed as a hollow shaft motor, wherein a lead screw is fixed at the hollow shaft, and an optical device for deflecting the laser beam onto the workpiece surface is fixed on the lead screw, wherein the hollow shaft is rotatable independently of the lens.

[0008] Because the lens is not fixed to the lead screw or hollow shaft and therefore does not rotate with the lead screw or hollow shaft, process accuracy is improved, thereby avoiding laser focus shift caused by lens rotation. The lens is advantageously arranged in the hollow shaft, allowing the hollow shaft to rotate around the lens.

[0009] Suitable design options for the invention are given in the dependent claims.

[0010] According to an advantageous design, the laser tool has a collimator arranged in the optical path after the laser source, the collimator being movable parallel to the laser beam by means of a driving device.

[0011] This is achieved advantageously by moving the collimator along the laser beam direction using a drive mechanism, allowing the focal position of the laser beam to be adapted or adjusted without manual intervention from the operator. Furthermore, the collimator provides stable guidance within the optical path.

[0012] According to a suitable extended design, the drive unit can be an electric drive unit, a pneumatic drive unit, or a hydraulic drive unit. The drive unit is particularly preferably a servo motor.

[0013] In another advantageous design, the lens is fixed to a lens tube, which in turn is fixed to a collimator. The lens, lens tube, and collimator thus form a unit that can be moved parallel to the laser beam by means of a drive device and thereby used to adjust the focal position of the laser beam. By firmly arranging the collimator and lens together in this configuration, the guidance of the laser beam is optimized, and more accurate positioning of the laser focal point is achieved.

[0014] In one advantageous embodiment, the drive unit has a length measuring system as an external position sensor for detecting the position of the collimator. Movement of the collimator parallel to the laser beam direction can be achieved, for example, by a ball screw. The length measuring system is connected to or integrated into the drive unit.

[0015] In another advantageous embodiment, the drive unit has a control device for controlling the movement of the collimator. This allows the movement of the collimator to be controlled according to at least one preset parameter. Furthermore, the control device processes signals from the length measurement system.

[0016] By controlling the movement of the collimator through preset parameters, process reliability and repeatability are advantageously improved. Furthermore, the focal position can be adjusted with particular precision for different cylinder diameters. It is particularly feasible to store parameters for different cylinder diameters in a memory located in the control device, thereby enabling direct retrieval of these parameters during operation without manual equipment changes.

[0017] In another embodiment, at least one parameter may be the collimator feed toward the optical device or the collimator feed toward the laser source. Feeding the collimator toward the optical device here indicates that the focal point moves forward toward the workpiece surface, and feeding the collimator toward the laser source similarly indicates that the focal point moves away from the workpiece surface.

[0018] According to another advantageous design, the laser tool has at least one lower stop that limits the movement of the collimator toward the optical device. Furthermore, according to another embodiment, the laser tool has at least one upper stop that limits the movement of the collimator toward the laser source.

[0019] According to another advantageous design, the optical device is a steering prism, or a reflecting prism or mirror. The steering prism is fixed to the end of the lead screw furthest from the laser source and thus rotates with the lead screw to move away from the workpiece surface by rotation. The steering prism or mirror is threadedly connected to a holding device connected to the lead screw by a plurality of screws. However, other optical elements designed for deflecting the laser beam, such as mirrors, are also conceivable.

[0020] Furthermore, according to a suitable design, the laser tool includes an adjustment unit that adjusts the movement of the collimator based on signals from a sensor. This sensor, for example, measures the intensity of the laser spot and compares it to a rated value or threshold. When the intensity exceeds or falls below this rated value or threshold, the drive automatically readjusts the position of the collimator, thereby readjusting the position of the laser beam focus. The result is a better surface structure according to pre-selected parameters. Furthermore, the system's economics are improved because the intensity of the laser source can be adapted to environmental influences and the system is continuously calibrated.

[0021] In addition, the present invention relates to a method for adjusting the focal position of a laser beam in a laser tool according to the invention. The laser tool has a laser source for generating a laser beam and a collimator for generating a parallel optical path of the laser beam. The laser beam is guided through a lens, wherein the lens is arranged within a rotatable leadscrew. The laser beam is then guided through an optical device located at the end of the leadscrew opposite to the laser source and deflecting the laser beam onto the surface of a workpiece. The collimator can be moved parallel to the laser beam by means of a drive device, and at least one parameter is preset by means of a control device that controls the movement of the collimator, wherein the collimator moves toward or opposite to the direction of the optical device according to the at least one parameter.

[0022] According to an advantageous design of the method, the at least one parameter is the collimator feed toward the optical device or the collimator feed toward the laser source.

[0023] Furthermore, according to an advantageous design of the method, the lens is fixedly arranged in a lens tube, which is fixed to the collimator, so that the lens moves with the collimator. Attached Figure Description

[0024] The embodiments of the present invention are described in detail below with reference to the accompanying drawings. In the drawings:

[0025] Figure 1 A cross-sectional view of the laser tool is shown.

[0026] Preferred embodiments of the present invention

[0027] Figure 1 A laser tool (100) is shown in a cross-sectional view. The fiber of the laser source (10) is connected to the laser tool (100) via a collimator (11). The collimator (11) is fixed to a fixed sleeve (26), which is connected to a drive unit (15) via an adjusting bracket (25). The drive unit (15) moves along a guide shaft (23) by means of a ball screw (21). A lens tube (18) is also fixed to the sleeve (26), and a lens (12) is fixed to the end of the lens tube away from the sleeve (26). The optical path of the laser beam (10a) from the laser source (10) extends here through the collimator (11), the sleeve (26), the lens tube (18), and the lens (12) to the optical device (14).

[0028] The unit, consisting of a laser source (10), collimator (11), sleeve (26), lens tube (18), and lens (12), is connected to the drive device (15) via an adjusting bracket (25) and is thus able to move as a unit parallel to the laser beam. The movement of this focusing unit is limited by an upper stop (17) and a lower stop (16).

[0029] The laser tool (100) also has a control device, not shown in detail in the figure, for controlling the movement of the collimator (11). To control the movement of the collimator (11), one or more parameters can be preset, thus, for example, the feed of the collimator (11) toward the optical device (14) or the feed of the collimator toward the laser source (10) can be preset. The laser tool (100) also has an adjustment unit, not shown in detail, which adjusts the movement of the collimator (11) and thereby adjusts the focal position in the process according to, for example, signals from sensors, and calibrates the system in terms of focal position.

[0030] To rotate the laser beam, the laser tool (100) has a lead screw (13) fixed to and driven by the hollow shaft (20) of a hollow shaft motor (19). A lens tube (18) and a lens (12) are arranged inside the hollow shaft (20). All components of the hollow shaft motor (19) are supported by bearings (24).

[0031] An optical device (14) is fixed at the end of the lead screw (13) away from the hollow shaft motor (19). The optical device (14) rotates together with the lead screw (13). The optical device (14) includes a deflecting prism (28) that deflects the laser beam (10a) onto the workpiece surface (30). In addition, a sensor (22) with a read head is arranged in the area of ​​the lead screw, which detects the position of the lead screw and thereby detects the position of the laser beam (10a).

[0032] List of reference numerals

[0033] 100 laser tools

[0034] 10 laser sources

[0035] 10A laser beam

[0036] 11 Collimator

[0037] 12 lenses

[0038] 13-screw

[0039] 14 Optical Devices

[0040] 15 drive units

[0041] 16 lower stop

[0042] 17 upper stop

[0043] 18 lens tube

[0044] 19 Hollow Shaft Motor

[0045] 20 hollow shafts

[0046] 21 ball screw

[0047] 22 sensors

[0048] 23 guide axes

[0049] 24 bearings

[0050] 25 Adjustable Angle Fittings

[0051] 26 sleeve

[0052] 28 Steering Prisms / Mirrors

[0053] 30 workpiece surface

Claims

1. A laser tool (100), in particular for structuring a cylinder working surface, having a laser source (10) for generating a laser beam (10a), which is guided through a lens tube (18) located in a hollow shaft (14), wherein A lens (12) is fixed on the lens tube (18), through which the laser beam (10a) is guided, wherein the hollow shaft (19a) is designed as a hollow shaft motor (19) which is rotatable, wherein a spindle (13) is fixed at the hollow shaft (19a) for deflecting the laser beam (10a) onto the workpiece surface (30), and an optical device (14) for deflecting the laser beam (10a) onto the workpiece surface (30) is fixed on the spindle (13), characterized in that the laser tool (100) has a collimator (11) which is arranged in the beam path behind the laser source (10), which collimator can be moved parallel to the laser beam (10a) by means of a drive device (15), wherein the lens tube (18) is fixed on the collimator (11) and the lens (12) does not rotate with the spindle (13), and the hollow shaft (19a) can be rotated independently of the lens (12).

2. The laser tool (100) according to claim 1, characterized in that The drive device (15) is an electric drive device, in particular a servo motor, a hydraulic drive device or a pneumatic drive device.

3. Laser tool (100) according to one of the preceding claims, characterized in that The collimator (11) and the lens tube (18) are fixedly connected to a sleeve (26).

4. Laser tool (100) according to one of the preceding claims, characterized in that The drive device (15) has an external position sensor.

5. Laser tool (100) according to one of the preceding claims, characterized in that The drive device (15) has a control device for controlling the movement of the collimator (11) depending on at least one predefinable parameter.

6. Laser tool (100) according to one of the preceding claims, characterized in that The at least one parameter is the feed of the collimator (11) in the direction of the optical device (14) or the feed of the collimator (11) in the direction of the laser source (10).

7. Laser tool (100) according to one of the preceding claims, characterized in that The laser tool (100) has at least one lower stop (16) and / or an upper stop (17) which limits the movement of the collimator (11).

8. Laser tool (100) according to one of the preceding claims, characterized in that The optical device (14) is a turning prism or a mirror (28).

9. Laser tool (100) according to one of the preceding claims, characterized in that The laser tool (100) has an adjustment unit which adjusts the movement of the collimator (11) depending on a signal of a sensor.

10. A method for adjusting a focal point position of a laser beam (10a) in a laser tool (100), the laser tool having a laser source (10) for generating a laser beam (10a) and a collimator (11) for generating a parallel run of the laser beam (10a) from the laser source (10), the collimator (11) being arranged in the optical path after the laser source (10), the laser beam being guided through a lens (12), wherein, The lens (12) is arranged in a rotatable spindle (13), wherein an optical device (14) for deflecting the laser beam (10a) onto the workpiece surface (30) is fixed on the end of the spindle (13) which faces away from the laser source (10) and the collimator (11) can be moved parallel to the laser beam (10a) by means of a drive device (15), wherein at least one parameter is predefined by means of a control device which controls the movement of the collimator (11), wherein the collimator (11) is moved in the direction of the optical device (14) or in the opposite direction of the optical device (14) depending on the at least one parameter, wherein the collimator (11) can be moved parallel to the laser beam (10a) by means of the drive device (15), wherein the lens (12) and the collimator (11) are fixedly secured to one another and the lens (12) does not rotate with the spindle (13).

11. The method of claim 10, wherein, The at least one parameter is the feed of the collimator (11) in the direction of the optical device (14) or the feed of the collimator (11) in the direction of the laser source (10).

12. The method of claim 10 or 11, wherein, The lens (12) is fixedly arranged in a lens tube (18), which is fixed on the collimator (11).

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