Machine tool, especially for the manufacture of balls, ball-like objects or switching balls

Abstract

Machine tool (1), in particular for the manufacture of balls or ball-like objects, in particular switching balls, comprising: - a processing chamber (5), - a workpiece spindle (55) that rotates a workpiece around a central axis, - a robot (20), characterized by the following additional features: - the robot (20) has a gripper arm (21) wherein a motor spindle (25) is arranged on the gripper arm (21), - the robot (20) or at least the gripper arm (21) of the robot (21) enters the processing space (5), - A tool with a geometrically undefined cutting edge is inserted into the motor spindle (25) for grinding or polishing the workpiece within the machining area.

Description

[0001] The invention relates to a machine tool, in particular for the manufacture of spheres, sphere-like objects or switching spheres according to the features of the preamble of claim 1 and an associated manufacturing method as well as a switching sphere produced by such a manufacturing method.

[0002] The production of spherical surfaces, such as those of switching balls, requires numerous work steps. One of the most complex steps is vibratory finishing, described in DIN 8589. Vibratory finishing, preferably drum vibratory finishing, involves a grinding process as well as a lapping and polishing process, resulting in a workpiece that is deburred, ground, and polished at the end of the process. In vibratory finishing, the workpieces to be processed are placed in a work container as bulk material along with abrasive media and usually an aqueous solution. A rotating or oscillating movement along the longitudinal axis of the work container creates a relative motion between the workpiece and the abrasive, which removes material from the workpiece, particularly from its edges. After this step, the workpieces must be manually removed from the bulk material.

[0003] The disadvantages of vibratory finishing are therefore the long process times and the commitment of personnel resources.

[0004] This problem is solved by a machine tool for manufacturing balls or ball-like objects, in particular switching balls, with the features of claim 1 and a method for manufacturing a workpiece, in particular a switching ball, according to the features of claim 15.

[0005] Advantageous embodiments and further developments of the invention are specified in the dependent subclaims.

[0006] According to the invention, a machine tool, particularly for the production of spheres or sphere-like objects, especially switching balls, is provided, comprising a machining chamber, a workpiece spindle that rotates the workpiece about a central axis, and a robot, wherein the robot has a gripper arm on which a motor spindle, also referred to as a spindle motor, is arranged. The robot, or at least the gripper arm of the robot, can be moved into the machining chamber. A tool with a geometrically undefined cutting edge is inserted into the motor spindle for grinding or polishing the workpiece within the machining chamber.

[0007] The invention is based on the idea of ​​performing a multitude of machining steps within a machine tool when manufacturing a spherical surface, particularly when manufacturing a switching ball. Specifically, the time-consuming drum vibratory finishing process is carried out by a robot within the machining area of ​​a machine tool.

[0008] Preferably, the robot's gripper arm is movable in at least two, and preferably in all three, spatial directions. The gripper arm can perform a linear movement, a rotation, a joint movement, or a combination of two or all three movements.

[0009] In a preferred embodiment of the invention, the robot's gripper arm comprises a front, middle, and rear gripper arm section, which are preferably connected to one another via a joint connection. The front gripper arm section is mechanically connected to the motor spindle. The rear gripper arm section is connected to a base frame, with the middle gripper arm section connecting the front and rear gripper arm sections. The motor spindle is preferably rotatably mounted on the front gripper arm section.

[0010] The rear gripper arm section can be connected to the base frame, which is preferably mechanically connected to the machine tool, via a hinged connection. A carousel can also be arranged between the rear gripper arm section and the base frame. The carousel performs a rotational movement around an axis.

[0011] The robot can also have only two gripper arms. A rear gripper arm section, preferably mounted to the base frame via a carousel, is connected to the front gripper arm section via a joint. The motor spindle is arranged on the front gripper arm section, preferably rotatably mounted.

[0012] The motor spindle includes a stator, a rotor, a tool holder, a tool interface, a tool clamping system, and a bearing.

[0013] The stator has an electrical winding, preferably made of copper or aluminum. The stator can have one or more poles. The number of poles significantly influences the speed and torque of the motor spindle. Preferably, the speed range of the motor spindle is between 0 and 3000 rpm, particularly preferably between 0 and 1500 rpm.

[0014] The rotor of a motor spindle can be self-excited or separately excited. A separately excited rotor has a coil that is energized with a direct current, thereby generating a magnetic field that follows the field of the stator synchronously. However, the rotor can also contain permanent magnets or consist entirely of ferromagnetic material. The rotor can follow the magnetic field of the stator synchronously or asynchronously.

[0015] According to a preferred embodiment of the invention, the motor spindle has a floating bearing, preferably an air bearing or a rolling bearing.

[0016] The rolling bearing can be designed as a ball bearing or a roller bearing. Preferably, the bearings are arranged at the end of the rotor. Double-row angular contact ball bearings are preferably used to support the motor spindle, with the double-row angular contact ball bearing always located at the end of the rotor. A benefit of double-row angular contact ball bearings is that they offer higher load-carrying capacity due to the two rows. They also exhibit greater stiffness and stability, which particularly improves precision and reliability. Another advantage is that double-row angular contact ball bearings can accommodate a certain amount of axial displacement between the shaft and the housing.

[0017] The motor spindle can also be mounted using an air bearing system. In this system, air nozzles are preferably arranged symmetrically around the circumference of the motor spindle, creating an air cushion between the rotor and stator. The advantage of air bearings is that they offer support in both axial and radial directions. Furthermore, air bearings can be used to cool the rotor. Preferably, a tool holder is arranged at one end of the motor spindle. The tool holder has a receiving system for holding a tool. The workpiece can then be machined using the mounted tool.

[0018] According to an advantageous embodiment of the invention, the robot has a tool holder arranged on the motor spindle and equipped with a grinding tool and / or a polishing tool. The robot can also accommodate other tools for machining a workpiece.

[0019] A grinding tool, such as a grinding wheel, is considered a tool with a geometrically indeterminate or undefined cutting edge. In a grinding wheel, the individual abrasive grains have different shapes and positions relative to the workpiece. Polishing tools are also considered tools with undefined cutting edges.

[0020] Preferably, the grinding tool, in particular the tool holder into which the grinding tool can be inserted, is arranged to float or be gimbal-mounted on the motor spindle.

[0021] In a gimbal mounting, the tool holder is relatively movable relative to the motor spindle in several degrees of freedom. A gimbal mounting has an inner joint component and an outer joint component, which are connected to each other via a joint element.

[0022] According to an advantageous embodiment of the invention, the motor spindle is connected to the tool holder via a ball joint. The ball joint has a ball head and a ball socket. The ball head is preferably arranged at the end of the motor spindle facing the tool holder. The ball socket is preferably formed on the tool holder. The ball head is positively engaged in the ball socket and allows rotational movement in three axes. Additionally, a chamber is provided so that the ball head and ball socket can disengage from each other, allowing the tool holder, relative to the motor spindle, to perform a stroke movement along the longitudinal axis of the motor spindle. The stroke movement is preferably 10 mm long.

[0023] In a particularly preferred embodiment of the invention, the motor spindle is connected to the tool holder via a bellows coupling. A bellows coupling comprises a bellows, which is an elongated, corrugated tube or sleeve. The bellows coupling is preferably made of a metal, particularly preferably stainless steel or aluminum. The bellows coupling is designed to compensate for radially acting forces. Forces in axial, lateral, or angular directions can also be compensated by the bellows coupling. The bellows coupling connects the motor spindle to the tool holder. Torque is transmitted from the motor spindle to the tool holder via the bellows coupling. At its ends, the bellows coupling is usually fastened to the components to be coupled by means of hubs.

[0024] Advantageously, the contact force of the grinding tool and / or polishing tool on the workpiece can be adjusted by means of a pneumatic or spring mechanism. A spring is arranged between the motor spindle and the tool holder system.

[0025] The motor spindle also advantageously features a tool changing system. Tool changes can be performed manually. Alternatively, a quick-change system can be used, employing collets, hydraulics, pneumatics, or magnets to quickly and precisely release the tool. This quick-change system can be semi-automatic or fully automatic. A robot can also assist the tool changing system.

[0026] Preferably, the motor spindle has a tool changing system, preferably a zero-point clamping system. The zero-point clamping system has a clamping element that is hydraulically, pneumatically, or mechanically operated and clamps the tool securely. A zero point is defined on the worktable at which the tool change preferably takes place.

[0027] According to an advantageous embodiment of the invention, the motor spindle has an HSK quick-change system.

[0028] According to a particularly preferred embodiment of the invention, the machine tool has a tool turret with a cutting tool, a milling tool, a drilling tool, a brushing tool and / or a turning tool. The tool turret can also accommodate other tools.

[0029] Preferably, the motor spindle is lightweight, preferably less than or equal to 10 kilograms, and particularly preferably less than or equal to 7 kilograms. However, the motor spindle can also weigh more than 10 kilograms. In this case, the payload capacity of the robot's gripper arm must be taken into account. Due to the limited installation space within the machine tool, only smaller robot models can be used, which generally have a lower payload capacity.

[0030] According to a particularly preferred embodiment of the invention, the robot can be moved completely out of the machining chamber and is preferably physically decoupled from the machining chamber by means of a cover. This protects the robot, in particular from chips and other contaminants, during the machining process. The robot is moved into and out of the machining area of ​​the machine tool on a rail.

[0031] The machine tool used is preferably a standard machine tool. The machine tool comprises a machining area, a workpiece spindle, a tool turret, a pick-up spindle, preferably a bar feeder and / or fine filtration system, and an unloading device.

[0032] The machine tool has a machining area and a protective chamber, the machining area and the protective chamber being separable from each other by a cover. When closed, no chips or liquids can enter the protective chamber from the machining area.

[0033] The machine tool has a machine bed as its base, which supports all other components.

[0034] In the machining process, the workpiece spindle holds the workpiece and rotates it. By bringing a tool close to the rotating workpiece spindle and workpiece, manufacturing processes such as milling, drilling, turning, or grinding can be carried out.

[0035] The tool turret holds the various tools for the different machining processes. For example, a milling cutter, drill, or tap is stored inside the tool turret when not needed for the respective machining step.

[0036] The pick-up spindle serves to remove the workpiece previously machined in the workpiece spindle and transfer it to an unloading device, or to hold the workpiece in place to perform the grinding and / or polishing process before transferring the workpiece to the unloading device. The unloading device transports the finished workpieces out of the machine tool.

[0037] Advantageously, a second workpiece spindle is arranged within the machining area. The transfer spindle moves the workpiece from the first workpiece spindle to the second workpiece spindle, where the grinding and / or polishing and / or deburring process can be carried out.

[0038] Advantageously, a bar feeder is provided to supply the material to the machine tool. The bar feeder inserts the material into the machine tool and transfers it to the workpiece spindle. The bar feeder has a linear rail, a carriage, and bearings. The workpieces or material can also be manually inserted or placed into the machine tool.

[0039] Preferably, the robot can be controlled and / or regulated via a robot panel.

[0040] Advantageously, a fine filtration system is integrated into the machine tool to remove the chips generated during the machining process. The primary function of this system is to purify the coolant by removing impurities and returning it to the cooling circuit. Grinding processes, in particular, produce extremely fine chips, making the filtration process both complex and crucial. The filtration system comprises a filter unit, a pump system, a reservoir, and a control system.

[0041] According to the invention, a method for manufacturing a workpiece with a machine tool is used, in which a workpiece that is at least partially or approximately spherical is provided. Subsequently, the motor spindle, attached to a gripper arm of the robot, is moved into the machining chamber, and the workpiece is ground and polished using the robot with a motor spindle and a tool with a geometrically undefined cutting edge arranged on the motor spindle.

[0042] Advantageously, after the robot enters the tool holder of the motor spindle, a roughing tool is inserted. The workpiece is then roughed. Afterward, the roughing tool is replaced with a finishing tool, and the workpiece is subsequently finished. The roughing and finishing processes are integral parts of the grinding process. Finally, the finishing tool is replaced with a polishing tool, and the workpiece is polished. The polishing tool is then transferred to the tool turret, and the robot moves out of the machining chamber.

[0043] Advantageously, the spherical workpiece is produced by removing material from a rod-shaped workpiece using one or more tools, whereby tools with a geometrically defined cutting edge are used, in particular tools for turning, milling, parting off, or drilling processes. The workpiece is rigidly clamped in the workpiece spindle and rotates. The tool is rigid and is brought into contact with the rotating workpiece, and a material removal process takes place.

[0044] Preferably, the robot is positioned within a protective chamber during the machining processes, which is separated from the machining area by a cover. Only when the machining process, which includes milling, turning, and drilling, is completed, does the cover open and the robot move into the machining area on a rail guide.

[0045] According to an advantageous step of the invention, the motor spindle is attached to a front gripper arm section of the robot, wherein the gripper arm of the robot, preferably the entire robot, is moved into the machining chamber. The motor spindle is movably arranged on the front gripper arm section.

[0046] In a further advantageous process step, the workpiece is ground using one or more grinding tools, wherein the grinding tool can be attached to the motor spindle, which has a floating bearing. The grinding tool preferably comprises a grinding wheel with a geometrically undefined cutting edge. Different grinding tools can be used. For example, one grinding tool can be used for roughing and another for finishing.

[0047] Advantageously, the robot performs a rotational movement during the grinding process, with the workpiece at the center of rotation and the radius of rotation being variable. In addition, the motor spindle can perform a further rotational movement and variably adjust the contact pressure on the workpiece. The rotational movement can be executed in different paths, with the path of rotation varying within a single rotational movement.

[0048] The tool's contact pressure on the workpiece is advantageously adjustable with high dynamics via a pneumatic system or a spring mechanism. For example, the air pressure within a pressure chamber directly adjacent to the tool holder can be adjusted. Guide elements stabilize movement in the axial direction. Preferably, the stroke range in the axial direction is between 0 and 20 millimeters, and particularly preferably between 0 and 10 millimeters.

[0049] Following the fine grinding process, the workpiece is preferably polished. For this purpose, the grinding tool, which is stored in the tool holder located on the motor spindle, is placed in the tool turret, and the polishing tool is inserted into the tool holder. The motor spindle preferably has a tool changing system for this purpose, preferably a zero-clamping system or an HSK tool changing system.

[0050] According to an advantageous step of the invention, the workpiece material is fed into the machine tool in bar form via a bar feeder. The workpiece material fed into the machine tool can also have a shape other than that of a bar. The fed workpiece material is transferred to the workpiece spindle. Before or after this, the tool bar is cut to the required workpiece size.

[0051] In another advantageous process step, a machining process with a defined cutting edge, such as turning, and a machining process, such as grinding, take place simultaneously within the machining area. This significantly increases production speed. For this purpose, the robot is positioned in the machining chamber while machining one workpiece with a defined cutting edge and simultaneously machining another workpiece with a tool with an undefined cutting edge.

[0052] In a further advantageous process step, the workpiece provided has indentations and / or cavities. Preferably, the cavities and / or indentations are first deburred before the grinding process.

[0053] In a further advantageous process step, after machining the workpiece with a defined cutting edge, the workpiece is transferred to a picking spindle.

[0054] The workpiece to be machined is held by the pick-up spindle while it is separated from the workpiece by the main spindle. The pick-up spindle must operate synchronously with the workpiece spindle to ensure smooth picking and holding of the workpiece.

[0055] The pick-up spindle then transfers the workpiece to an unloading device, which transports the finished workpiece from the machine tool. After the workpiece is transferred to the pick-up spindle, one or more machining processes with an undefined cutting edge can also be performed. For example, a grinding and / or polishing process can be carried out. The workpiece is then transferred to the unloading device, which transports the finished workpieces from the machine tool.

[0056] The pick-up spindle can also transfer the workpiece to a second workpiece spindle for subsequent machining operations using a tool with an undefined cutting edge. The workpiece can then be directly transferred to an unloading device, or the pick-up spindle can grip the workpiece and transfer it to the unloading device.

[0057] In a preferred process step, the lubricant is cleaned of chips and other contaminants by means of a filtration system and returned to the lubricant circuit. The chips are transported out of the machine tool, preferably by means of a conveyor belt.

[0058] According to the invention, a spherical workpiece, in particular a switching ball, is used.

[0059] An embodiment of the invention will be explained in detail below with reference to the following figures: The figures show Fig. 1. A side view of the entire system with bar feeder, machine tool with robot and unloading device, Fig. 2 an interior view of the machine tool, wherein the robot is arranged in the machine tool outside the machining area, Fig. 3 A view of the machine tool in which the robot is performing a grinding or polishing process, Fig. Figure 4 shows a cross-section through a first embodiment of a motor spindle and a tool holder connected to the motor spindle via a bellows coupling, on which a grinding tool is clamped, and Fig. Figure 5 shows a cross-section through a second embodiment of the motor spindle, wherein the motor spindle is floatingly mounted with the tool holder via a ball joint.

[0060] In all figures, identical reference numerals denote identical or functionally equivalent parts, although for the sake of clarity not all reference numerals are shown in all figures.

[0061] Fig. Figure 1 shows the side view of the entire system 100, which includes a bar loader 40, a machine tool 1 with robot 20 and an unloading device 50.

[0062] The bar feeder 40 is designed to feed workpiece material into the machine tool 1 via an access point. The workpiece material is transferred to the machine tool 1 in the form of long bars. Preferably, the workpiece bars are two to three meters long. The workpiece bars can also be longer or shorter. The workpiece material can also have a different shape; for example, it can be cuboid.

[0063] The machine tool 1 has a machine frame 2 and an outer casing 3. A machining chamber 5 is formed within the machine tool 1. A protective chamber 7 (not shown) is located directly adjacent to the machining chamber 5. The machining chamber 5 and the protective chamber 7 can be separated from each other by a cover 6. The cover 6 (not shown) can be opened and closed by means of a motor, preferably an electric motor. When closed, the protective chamber 7 is sealed off from the machining chamber 5 in such a way that no chips or liquids from the machining chamber 5 can enter the protective chamber 7.

[0064] Inside the machine tool 1 are arranged a robot 20, a workpiece spindle 55, a second workpiece spindle 60, a tool spindle 65, a pick-up spindle 70, a tool turret 30, a fine filtration system 35 (not shown), a control unit 75 and parts of an unloading device 50.

[0065] The unloading device 50 removes the finished workpieces from the machine tool 1. The workpieces can also be removed from the machine tool 1 manually or by means of a robot 20. The unloading device 50 preferably has a conveyor belt 51 on which the workpieces are transported out of the machine tool 1. Preferably, a conveyor belt 51 with knobs and / or dividers is used so that the preferably spherical workpieces do not roll onto each other.

[0066] In Fig. Figure 2 shows the machine tool 1 without its outer casing 3. The robot 20 is positioned in a first position, in which the robot 20 does not perform any machining process.

[0067] The robot 20 has three gripper arms 21, namely a front gripper arm section 22, a rear gripper arm section 24, and a gripper arm section 23. The middle gripper arm section 23 connects the front gripper arm section 22 with the rear gripper arm section 24. The gripper arm sections 22, 23, 24 are preferably connected to each other via a joint 45. The joint 45 allows the gripper arm sections 22, 23, 24 to be movable relative to each other in three spatial directions. The robot 20 can also have only two gripper arm sections 22, 24, namely a front and a rear gripper arm section 22, 24. These can also be connected to each other via a joint 45.

[0068] The rear gripper arm section 24 is connected to a base frame 18 via a carousel 19. The carousel 19 is rotatably mounted. The rear gripper arm section 24 can also be connected to the base frame 18 by a joint connection 45.

[0069] The base frame 18 of the robot 20 preferably includes a rail element 17 (not shown). The rail element 17 engages in a complementary rail guide 16, which is attached to the machine tool 1. The rail guide 16 is located within the machining area 5 and the protective chamber 7. The robot 20 can be moved from a first position in the protective chamber 7 to a second position in the machining chamber 5 and vice versa via a rail device 15, which consists of the rail element 17 and the rail guide 16, by means of an electrical or mechanical drive. The robot 20 can be fully retracted into the protective chamber 7.

[0070] A motor spindle 25 is arranged on the front gripper arm section 22. The motor spindle 25 is rotatably mounted on the front gripper arm section 22. The motor spindle 25 can also be connected to the front gripper arm section 22 via a joint connection 45. Alternatively, the motor spindle 25 can be rigidly connected to the front gripper arm section 22.

[0071] A workpiece spindle 55 is arranged within the machining chamber 5. The workpiece spindle 55 is rotatably mounted. For this purpose, the workpiece spindle 55 comprises a motor, preferably an electric motor, a workpiece holder, a spindle shaft, and a spindle housing. The drive system of the workpiece spindle can also be hydraulic or pneumatic. The workpiece spindle can be rigidly arranged within the machining chamber 5 or be movable in all three or two spatial directions. The workpiece spindle 55 can also be movable in only one spatial direction. Electric motors are preferably used for this purpose. The workpiece spindle 55 can also have a collet and a tool change system 27.

[0072] The tool turret 30 is located below the workpiece spindle 55. The tool turret 30 has a turret body that is mounted on the machine tool. The tool turret 30 also has tool holders. For example, a milling, turning, or grinding tool can be inserted into the tool holder. The tool turret 30 also has a drive system, in particular for rotating around its own axis and positioning the required tool. The drive system can be pneumatic, hydraulic, or electric. The tool turret 30 also has a tool clamping system to prevent the tools from unintentionally falling out of the tool holders. Sensors can also be integrated to monitor the positioning and condition of the tools.

[0073] The pick-up spindle 70 is arranged at 180 degrees relative to the workpiece spindle 55. The pick-up spindle 70 is movable in all three spatial directions within the machining chamber 5 of the machine tool 1.

[0074] The pick-up spindle 70 comprises a spindle housing, a spindle shaft, collets or clamping jaws, a drive system, and sensors. The pick-up spindle 70 holds the workpiece during the separation process from the workpiece material while it is clamped in the workpiece spindle 55 and transfers it to the second workpiece spindle 60 or the unloading device 50. Machining of the workpiece with a tool having an undefined cutting edge can also be performed while the workpiece is held by the pick-up spindle 70.

[0075] Below the pick-up spindle 70, a second workpiece spindle 60 is arranged. This is designed almost identically to the workpiece spindle 55. The second workpiece spindle 60 clamps the workpiece during the machining process(s) using one or more tools having an undefined cutting edge.

[0076] Fig. Figure 3 shows the robot 20 in its second position. In this position, the robot 20 processes the workpiece with a tool that has an undefined cutting edge. During the processing, the workpiece, which is clamped in the second workpiece spindle 55, rotates. The workpiece can also be clamped in the pick-up spindle 70.

[0077] Fig. Figure 4 shows a first embodiment of a motor spindle 25. The motor spindle 25 is arranged on the gripper arm 21, preferably on the front gripper arm section 22 of the robot 20. The motor spindle 25 is preferably rotatably mounted on the front gripper arm section 22.

[0078] The motor spindle 25 has a stator 85, a rotor 86 and a bearing.

[0079] The motor spindle 25 is mounted as a rolling bearing, specifically a double-row angular contact ball bearing 87. The double-row angular contact ball bearing 87 is located at each end of the rotor 86. The motor spindle 25 can also be mounted as an air bearing.

[0080] An HSK quick-change system 80 is formed at one end of the motor spindle 25.

[0081] The motor spindle 25 incorporates a pneumatic system 88. The pneumatic system 88 regulates the pressure in a pressure chamber 89, which is formed at the connection point with a tool holder 90. By adjusting the air pressure within the pressure chamber 89, the contact force on the workpiece can be dynamically adjusted. The contact force can also be adjusted by means of a spring mechanism.

[0082] The motor spindle 25 also has guide elements 91 that stabilize the stroke in the axial direction. The stroke range is necessary due to the different contact forces on the workpiece.

[0083] The motor spindle 25 and the tool holder 90 are connected to each other via a bellows coupling 92. The bellows coupling 92 is connected to both the motor spindle 25 and the tool holder 90 via hubs. The bellows coupling 92 is preferably made of metal.

[0084] A grinding tool with a grinding wheel is inserted into the tool holder 90. Grinding tools for finishing or polishing tools can also be inserted into the tool holder 90.

[0085] Fig. Figure 5 shows a second embodiment of a motor spindle 25. The motor spindle 25 is arranged on the gripper arm 21, preferably on the front gripper arm section 22 of the robot 20. The motor spindle 25 is preferably rotatably mounted on the front gripper arm section 22.

[0086] The motor spindle 25 has a stator 85, a rotor 86 and a bearing.

[0087] The motor spindle 25 is mounted as a rolling bearing, specifically a double-row angular contact ball bearing 87. The double-row angular contact ball bearing 87 is located at each end of the rotor 86. The motor spindle 25 can also be mounted as an air bearing.

[0088] An HSK quick-change system 80 is formed at one end of the motor spindle 25.

[0089] The motor spindle 25 incorporates a pneumatic system 88. The pneumatic system 88 regulates the pressure in a pressure chamber 89, which is formed at the connection point with a tool holder 90. By adjusting the air pressure within the pressure chamber 89, the contact force on the workpiece can be dynamically adjusted. The contact force can also be adjusted by means of a spring mechanism.

[0090] The motor spindle 25 also has guide elements 91 that stabilize the stroke in the axial direction. The stroke range is necessary due to the different contact forces on the workpiece.

[0091] The motor spindle 25 and the tool holder 90 are connected to each other via a ball joint 95. The motor spindle 25 has a ball head 97 of the ball joint 95 at its end facing the tool holder 90. The tool holder 90 has a ball socket 96 into which the ball head 97 of the ball joint 95 of the motor spindle 25 can be positively inserted. The ball joint 95 allows rotational movement in three axes.

[0092] Additionally, a lifting movement of the tool holder 90 along the longitudinal axis of the motor spindle 25 is possible. The connection between the tool holder 90 and the motor spindle 25 is designed such that the ball head 97 can be extended from the ball socket 96. The distance between the ball socket 96 and the ball head 97 is limited by the design of the tool holder 90 and the motor spindle 25. Preferably, a lifting movement of 10 mm is possible.

[0093] A grinding tool with a grinding wheel is inserted into the tool holder 90. Grinding tools for finishing or polishing tools can also be inserted into the tool holder 90. Reference symbol list 1 machine tool 2 machine frames 3 Exterior cladding 5 processing chamber 6 Cover 7 Protective chamber 15 Rail device 16 Rail guide 17 rail element 18 Base frame 19 Carousel 20 robots 21 Gripper arm 22 Front gripper arm 23 Middle gripper arm 24 Rear gripper arm 25 Motor spindle 27 Exchange system 30 tool turrets 31 Grinding tool 35 Fine filtration system 40 bar loaders 45 Joint connection 50 unloading device 51 Conveyor belt 55 workpiece spindle 60 Second workpiece spindle 65 Tool spindle 70 Pickup spindle 75 Control unit 80 HSK exchange system 85 Stator 86 Rotor 87 Angular contact ball bearings 88 Pneumatic system 89 Pressure chamber 90 tool holders 91 guide elements 92 Bellows coupling 95 ball joint 96 ball pan 97 Ball head 100 Total system

Claims

[1] Machine tool (1), in particular for the manufacture of balls or ball-like objects, in particular switching balls, comprising: - a processing chamber (5), - a workpiece spindle (55) that rotates a workpiece around a central axis, - a robot (20), characterized by the other features: - the robot (20) has a gripper arm (21) wherein a motor spindle (25) is arranged on the gripper arm (21), - the robot (20) or at least the gripper arm (21) of the robot (21) can be moved into the processing chamber (5), - A tool with a geometrically undefined cutting edge is inserted into the motor spindle (25) for grinding or polishing the workpiece within the machining chamber (5). [2] Machine tool (1) according to claim 1, characterized by that the gripper arm (21) of the robot (20) is movable in at least two, preferably three, spatial directions. [3] Machine tool (1) according to claim 1 or 2, characterized by , that the gripper arm (21) of the robot (20) has a front, middle and rear gripper arm section (22, 23, 24) which are preferably connected to each other via a joint connection (45). [4] Machine tool (1) according to any one of claims 1 to 3, characterized by that the motor spindle (25) has a floating bearing, preferably an air bearing or a rolling bearing. [5] Machine tool (1) according to any one of claims 1 to 4, characterized by , that the robot (20) has a tool holder (90) connected to the motor spindle (25) and is equipped with a grinding tool and / or a polishing tool. [6] Machine tool (1) according to claim 5, characterized by , that the grinding tool is mounted floating or gimbal-mounted on the motor spindle (25) or on the tool holder (90). [7] Machine tool (1) according to any one of the preceding claims, characterized by that the motor spindle (25) has a tool changing system (27), preferably a zero-point clamping system or HSK changing system. [8] Machine tool (1) according to any one of claims 5 to 7, characterized by , that the motor spindle (25) is connected to the tool holder (90) via a ball joint (95). [9] Machine tool (1) according to any one of claims 5 to 8, characterized by , that the motor spindle (25) is connected to the tool holder (90) via a bellows coupling (92). [10] Machine tool (1) according to any one of claims 5 to 9, characterized by , that a contact force of the grinding tool and / or the polishing tool on the workpiece is adjustable by means of a pneumatic system (88) or a spring mechanism. [11] Machine tool (1) according to any of the preceding claims, characterized by, that the machine tool has a tool turret (30) with a cutting tool, a milling tool, a drilling tool, a brushing tool and / or a turning tool. [12] Machine tool (1) according to any of the preceding claims, characterized by that the robot (20) is fully movable out of the processing chamber (5) and is preferably physically decoupled from the processing chamber (5) by means of a cover (6). [13] Machine tool (1) according to any of the preceding claims, characterized by , that a bar feeder (40) is provided through which the workpiece material is fed to the machine tool (1). [14] Machine tool (1) according to any of the preceding claims, characterized by , that a fine filtration system (35) is provided which removes the chips produced in the grinding process from the machine tool (1). [15] Method for producing a workpiece with a machine tool (1) according to any one of claims 1 to 14 comprising the following method steps: - Providing a workpiece that is at least partially or approximately spherical, - Insertion of the motor spindle (25) attached to a gripper arm (21) of the robot (20) into the machining chamber (5), - Grinding and / or polishing of the workpiece using the robot (20) with a motor spindle (25) and a tool with a geometrically undefined cutting edge arranged on the motor spindle (25). [16] Method according to any of the preceding claims, characterized by , that the motor spindle (25) is attached to a front gripper arm section (22) of the robot (20), wherein the front gripper arm section (22) of the robot (20), preferably the robot (20) as a whole, is moved into the machining chamber (5). [17] Method according to any of the preceding claims, characterized by, that the grinding of the workpiece is carried out using one or more grinding tools (31) which are floatingly mounted on the motor spindle (25). [18] Method according to any of the preceding claims, characterized by , that the provision of the spherical workpiece is carried out by removing material from a rod-shaped material using one or more tools. [19] Method according to any of the preceding claims, characterized by , that the workpiece is polished after fine cylindrical grinding. [20] Spherical workpiece, in particular switching ball, manufactured according to one of the methods according to 14 to 18.

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