Loading and unloading device for machine tools for machining gears

Abstract

The device (1) for loading and unloading workpieces (40, 41) into and from a machine tool (30) for machining gears, in particular a hard precision machining machine (30), comprises a base (2), a carrier (3) arranged on the base (2) and rotatable about a first axis of rotation (D1) relative to the base (2), and gripping devices (11) arranged on the carrier (3) for gripping and releasing the workpieces (40, 41), the gripping devices (11) being respectively rotatable about a second axis of rotation (D2) independently of each other. The gripping arm (13, 14, 15) has at least two pivotable gripping arms (13, 14, 15), and the gripping arms (13, 14, 15) are pivotable relative to each other about a second rotation axis (D2) so that the gripping arms (13, 14, 15) can take a gripping position for gripping a workpiece (40, 41) and a release position for releasing the workpiece (40, 41) relative to each other, and the gripping arms (13, 14, 15) are pivotable about the second rotation axis (D2) in synchronization with each other at least in the gripping position.

Description

[Technical field]

[0001] The present invention relates to an apparatus for loading and unloading a workpiece on a machine tool for machining gears, the apparatus having a base and a carrier arranged on the base, the carrier being rotatable relative to the base about a first axis of rotation and comprising a gripping device for gripping and releasing the workpiece.

[0002] The invention further relates to a machine tool for gear grinding of workpieces, the machine tool comprising a device of the above-mentioned type. Furthermore, the invention relates to a method for loading and unloading the machine tool using the device according to the invention. [Background technology]

[0003] The so-called ring loader concept is known from the prior art. Apparatuses according to the ring loader concept have a gripping device, which is usually rotatable about a rotation axis and comprises several pairs of gripping arms. Each pair of gripping arms is designed to grip or release a workpiece independently of the other pairs of gripping arms. To transport one or more workpieces, the gripping device is rotated about the rotation axis after at least one pair of gripping arms has gripped a workpiece. Thereby, all pairs of gripping arms, including the pair of gripping arms that gripped the workpiece, are pivoted about the rotation axis at the same time.

[0004] Such devices known from the prior art have the disadvantage that the position of one pair of gripping arms relative to the other pair of gripping arms is fixed or cannot be changed due to the design of the gripping device. This means that by rotating the gripping device about a rotation axis, all pairs of gripping arms pivot simultaneously. The pairs of gripping arms cannot be used flexibly to grip or release the workpieces. This leads to a slowing down or limiting of the loading and unloading speed of the known devices. Furthermore, the maintainability of the known devices is also limited, especially since the gripping device is always spatially fixed relative to the machine tool to be loaded and unloaded. Summary of the Invention

[0005] The object of the present invention is to provide an apparatus for loading and unloading machine tools which belongs to the technical field mentioned at the beginning and which overcomes the above-mentioned problems and disadvantages of the prior art, in particular to provide an apparatus for loading and unloading machine tools which allows for quick and efficient loading and unloading of workpieces and which also has improved maintainability.

[0006] To solve this problem, an apparatus according to the invention for loading and unloading workpieces into and from a machine tool comprises a base, a carrier and a gripping device, preferably suitable for loading and unloading workpieces, in particular pre-toothed workpieces such as double-tooth gear blanks, into and from hard precision machining machines.

[0007] Alternatively or additionally, the device may be suitable for loading and unloading clamping means, grinding wheels or similar means provided for the machine tool onto and from the machine tool. Therefore, for the purposes of the present invention, the term "workpiece" is not limited to an object machined by a machine tool, but rather may also include means provided for the machine tool, in particular for the operation and / or maintenance of the machine tool.

[0008] The carrier of the device according to the invention is arranged on the base and is rotatable about a first axis of rotation relative to the base. The gripping device is provided on the carrier and is designed to grip and release the workpiece. Advantageously, the gripping device is arranged on the carrier such that the gripping device pivots about the first axis of rotation when the carrier rotates about the first axis of rotation.

[0009] According to the invention, the gripping device comprises at least two gripping arms. The gripping arms are each pivotable independently of one another about a second axis of rotation. Each gripping arm is pivotable relative to the other gripping arm about a second axis of rotation such that the at least two gripping arms can assume a gripping position and a release position relative to one another. In the release position, the gripping arms are arranged relative to one another such that the gripping arms can release the workpiece. This means that the gripping arms are preferably not able to transport the workpiece in the release position. In the gripping position, the gripping arms are arranged relative to one another such that the gripping arms can grip the workpiece, preferably together. For example, the gripping arms can transport the workpiece in the gripping position, in particular can transport the workpiece together. Furthermore, the gripping arms are pivotable synchronously with one another about the second axis of rotation at least in the gripping position. Independently of this, it can also be provided that the gripping arms are pivotable synchronously with one another about the second axis of rotation in the release position.

[0010] For the purposes of the present invention, the term "gripping" is understood to mean the clamping, in particular the clamping or jamming, of a workpiece between two gripping arms. Alternatively or additionally, the term "gripping" may also include gripping underneath the workpiece by the gripping arms. Preferably, the gripping arms are connected to the workpiece in the gripping position with a frictional and / or form-fitting connection.

[0011] For the purposes of the present invention, the term "release" is understood to mean the release of contact between the gripping arms and the workpiece. For example, the contact between the gripping arms and the workpiece may be released when the gripping arms change from a gripping position to a release position. The workpiece is preferably already considered to be released when the workpiece is in contact with only one gripping arm.

[0012] For the purposes of the present invention, the term "synchronous pivoting" is understood to mean a simultaneous pivoting of the gripping arms, in which the relative positions of the gripping arms with respect to each other do not change. For example, the gripping arms can be pivoted synchronously in the gripping position such that the workpiece is transported between the gripping arms in response to the pivoting movement of the gripping arms. In other words, a workpiece arranged between two gripping arms in the gripping position pivots about a second axis of rotation when the gripping arms pivot synchronously with each other about the second axis of rotation.

[0013] The pivotability of the gripping arms relative to the second axis of rotation according to the invention means that they can be controlled flexibly and independently of one another. This has the advantage that different gripping arms can form different pairs of gripping arms as required and thus the workpieces can be loaded and unloaded more quickly from the machine tool. Furthermore, the gripping arms can be spaced apart in the release position so that the workpieces can be processed unhindered by the machine tool. For example, the gripping arms can be pivoted relative to one another about the second axis of rotation in the release position so that the distance between the gripping arms is greater than the width of the abrasive of the grinding device of the machine tool. Additionally or independently of this, arranging the gripping device on a rotatable carrier has the effect of improving the accessibility of the individual components.

[0014] This has the advantage of improving the maintainability of the entire device. In a first exemplary embodiment of the device, a workpiece spindle is arranged on the carrier. The workpiece spindle is designed to rotate the workpiece arranged on the workpiece spindle. Advantageously, the gripping device is designed to load and unload the workpiece on the workpiece spindle. For example, it can be provided that the gripping arms of the gripping device change from a gripping position to a release position or from a release position to a gripping position at the loading point in order to release or grip the workpiece. The loading point is preferably arranged in the vicinity of the workpiece spindle, in particular above the workpiece spindle.

[0015] An embodiment in which the workpiece spindle is disposed on a carrier advantageously pivots the workpiece spindle about a first axis of rotation as the carrier rotates about the first axis of rotation. This has the advantage that the workpiece spindle may be more easily accessible for improved serviceability or may be moved to a measurement position. Furthermore, when the workpiece spindle is made accessible to a user by rotating the carrier, the workpiece spindle may also advantageously be manually loaded.

[0016] The workpiece spindle is rotatable about a third axis of rotation, in particular about a third axis of rotation. Preferably, the third axis of rotation is offset parallel to the first axis of rotation. Alternatively or additionally, the third axis of rotation can be arranged parallel to the second axis of rotation.

[0017] In another exemplary embodiment, the gripping device is movable along the second axis of rotation, in particular axially. Preferably, the gripping device is moved along the second axis of rotation after the gripping arm has changed from the gripping position to the release position and / or from the release position to the gripping position. Thereby, advantageously, the workpiece is raised or lowered by the gripping device, in particular after the gripping arm has changed from the release position to the gripping position or before the gripping arm has changed from the gripping position to the release position.

[0018] Preferably, the second axis of rotation is displaced parallel to the first axis of rotation, which has the advantage that the device has a compact design and the accessibility of the individual components is improved.

[0019] Furthermore, the offset of the two rotation axes means that a large number of adjustment positions can be assumed by the device, which increases the flexibility of use of the device. In a further advantageous embodiment, the gripping device can grip or release the workpiece independently of the position of the carrier. For example, the gripping device can be designed to grip or release the workpiece independently of the position of the carrier relative to the first axis of rotation. Alternatively or additionally, it can be provided that the gripping device can grip or release the workpiece during a rotational movement of the carrier relative to the first axis of rotation. Such an embodiment advantageously allows the device to load and unload the machine tool in a very flexible manner. In particular, it is conceivable that the machine tool can be loaded by the device even if the carrier occupies a position for maintenance. This has the advantage that the operational readiness of the device can be ensured continuously, i.e. at least partially also during maintenance operations.

[0020] The device for loading and unloading the machine tool can be equipped with a drive mechanism. Preferably, the gripping device is equipped with a drive mechanism. For example, the drive mechanism is arranged on the gripping device, in particular directly on the gripping device. The drive mechanism can be designed to drive the gripping arms independently of one another. Such a drive mechanism has the advantage that the gripping arms are always pivotable independently of one another about the second axis of rotation. Preferably, the drive mechanism is designed as a rotary drive.

[0021] In a further development of the above-mentioned embodiment, the drive mechanism comprises a plurality of drive means. The drive means can be, for example, electric motors and / or synchronous motors. Each drive means can be assigned to a respective gripping arm. For example, a first drive means can be assigned to a first gripping arm and a second drive means to a second gripping arm. A drive mechanism with a plurality of drive means has the advantage that the gripping arms can always be pivotable independently of each other about the second axis of rotation. In particular, if one drive means fails, it can be ensured that the other drive means continue to drive the other gripping arms. For example, the drive means can be designed in such a way that in the event of a failure the drive means switches to an idle mode, so that the assigned gripping arm is freely pivotable about the second axis of rotation.

[0022] Each gripping arm may be arranged on a drive ring. Each drive ring is mounted so as to be rotatable about the second axis of rotation. For example, the drive rings may be supported on a base body of the gripping device so as to be rotatable relative to one another via roller and / or plain bearings. Advantageously, each gripping arm of the drive ring is pivoted about the second axis of rotation when the corresponding drive ring rotates about the second axis of rotation. Directly allocating the gripping arms to the drive ring has the advantage that the gripping arms can be driven individually and independently of one another. The drive ring may be annular, in particular circular, semi-annular or partially annular. The drive ring may be connected to the respective gripping arm in a force-fit, form-fit and / or material-fit manner. Alternatively, it is also conceivable that the drive ring and the respective gripping arm are integrally formed, in particular integrally formed with one another.

[0023] Preferably, each gripping arm is disposed on a radially outer surface of the respective drive ring relative to the second axis of rotation. In a further embodiment in which the device has drive means and drive rings, each drive ring can have internal teeth and each drive means can have a spur gear with external teeth. Advantageously, the drive means and the drive ring are arranged relative to each other such that the external teeth of the drive means engage with the internal teeth of the drive ring. Advantageously, the engagement transfers the rotational movement generated by the drive means to the corresponding drive ring such that the drive ring rotates about the second axis of rotation. In particular, this drives a gripping arm arranged on the corresponding drive ring. Such a further development has the advantage that the rotational movement generated by the drive means can be transferred substantially without loss to the drive ring and thereby also to the corresponding gripping arm.

[0024] Alternatively or additionally, the drive means can drive the drive ring via other drive connections. For example, one or more drive rings with which the respective drive means engage can be provided with external teeth. Independently of this, chain drives and / or belt drives are also conceivable as drive connections between the drive ring and the drive means. Linear motors can also be used.

[0025] Alternatively, a curved guide can be used to guide the gripping arms. It is also conceivable to provide a gearbox between the drive mechanism and the gripping arm. For example, a gearbox can be provided between each drive means and the corresponding drive ring. Alternatively, the gearbox can be arranged only between the respective drive means and the drive ring. The gearbox can be designed for speed-up driving and / or reduction of the rotational movement of the drive mechanism, in particular of the respective drive means. The use of a gearbox can be particularly advantageous if the pivoting movement of the gripping arm about the second axis of rotation has to be very fine and / or if increased gripping forces are required.

[0026] In another exemplary embodiment, one gripping means may be arranged on one, several or each of the gripping arms. Irrespective of this, several gripping means may be arranged on one gripping arm. Advantageously, the gripping means are arranged on the corresponding gripping arm so as to face towards the cooperating gripping arm, in particular towards the gripping means of the cooperating gripping arm. The gripping means are preferably designed to contact the workpiece when the gripping arm is in the gripping position. For example, the gripping means may be designed to apply a clamping force to the workpiece in the gripping position. Alternatively or additionally, the gripping means may comprise a protrusion with which the workpiece can be gripped from below. This means that the workpiece is gripped from below by the protrusion of one or more gripping means, in particular when the corresponding gripping arm is changed from the release position to the gripping position or when it is in the gripping position.

[0027] The gripping means advantageously improves the frictional and / or positive locking between the gripping arms and the workpiece in the gripping position, which has the advantage that the workpiece can be transported more safely by the gripping device and in particular that the workpiece can be safely pivoted about the second axis of rotation.

[0028] The gripping device can be designed to grip several workpieces simultaneously. Advantageously, this means that the device for loading and unloading the machine tool can load and unload the machine tool quickly and effectively.

[0029] In an exemplary embodiment, the gripping device may comprise a first gripping arm, a second gripping arm and a third gripping arm. The second gripping arm is preferably provided between the first gripping arm and the third gripping arm in the circumferential direction of the second axis of rotation. In other words, the order of the gripping arms in the circumferential direction of the second axis of rotation may be constant regardless of their respective positions (gripping position and / or release position). Advantageously, this means that the gripping device is very easy to control. This has the advantage that the device for loading and unloading machine tools can be manufactured and operated in a cost-effective and time-saving manner.

[0030] In a further development of the above-mentioned embodiment, the gripping device can be designed such that the second gripping arm can assume a gripping or release position relative to the first gripping arm. Independently of this, it can be provided that the second gripping arm can assume a gripping or release position relative to the third gripping arm. In other words, the second gripping arm can be designed such that the second gripping arm can assume a gripping and / or release position on both sides. The second gripping arm can contact the workpiece on both sides in the circumferential direction of the second axis of rotation. Such a further development advantageously means that the workpiece can be gripped between the first gripping arm and the second gripping arm, regardless of the position of the second gripping arm relative to the third gripping arm. This also applies vice versa. This means that the workpiece can be gripped between the second gripping arm and the third gripping arm, regardless of the position of the second gripping arm relative to the first gripping arm.

[0031] An advantage of the further development, in which the second gripping arm is arranged between the first and the third gripping arm in the circumferential direction, is that the gripping device can, for example, not grip and / or release a workpiece, grip and / or release a workpiece between the first and the second gripping arm, grip and / or release a workpiece between the second and the third gripping arm or grip and / or release two workpieces simultaneously, thereby ensuring fast, efficient and flexible loading and unloading.

[0032] In a further exemplary embodiment of the device, the carrier is rotatable about a first axis of rotation such that the carrier is adjustable between an operating position and a maintenance position. In particular, the carrier can be rotated about a first axis of rotation such that it can be switched between an operating position and a maintenance position. Preferably, in the operating position, the machine tool is loaded and unloaded with workpieces by the device. In the maintenance position, the machine tool and / or the device can be maintained. Alternatively or additionally, the machine tool and / or the device can be manually loaded with one or more workpieces in the maintenance position. This has the advantage that the device is easily accessible to the user.

[0033] The carrier can be hydrostatically mounted on the base. The carrier can be hydrostatically mounted on the base in order to improve the rotatability of the carrier, in particular around the first axis of rotation. This has the advantage that even with heavy loads, in particular heavy workpieces with a self-weight of more than 100 kg for example, the carrier is still rotatable, in particular smoothly rotatable, about the first axis of rotation. In addition, hydrostatic bearings can make the connection between the carrier and the base highly rigid, allowing for precise positioning.

[0034] Regardless of this, the carrier may have a carrier tower, which is preferably arranged vertically on the carrier. Regardless of this, the carrier tower may be provided eccentrically on the carrier with respect to the first axis of rotation.

[0035] The outer surface of the carrier tower may define the carrier tower radially outwardly with respect to the second axis of rotation. For example, the gripping device may be arranged on the outer surface of the carrier tower. This advantageously means that the gripping device is easily accessible for maintenance operations.

[0036] The dressing device can be provided on the carrier. The dressing device can be designed to dress the abrasive material of a grinding device of a machine tool. Preferably, the dressing device is arranged radially offset on the carrier with respect to the first axis of rotation. This has the effect that when the carrier rotates, for example, about the first axis of rotation, the dressing device pivots about the first axis of rotation. This has the advantage that, by rotating the carrier about the first axis of rotation, the dressing device can be positioned relative to the abrasive material so that the abrasive material can be dressed by the dressing device. For this purpose, the carrier can, for example, take up a dressing position. Irrespective of this, the dressing device can also be made easily accessible to the user, in particular for maintenance operations, by rotating the carrier about the first axis of rotation.

[0037] In an exemplary further development of the above-mentioned embodiment, the dressing device may be movable relative to the carrier. Preferably, the dressing device is translationally movable relative to the carrier. In particular, the dressing device may be movable relative to the carrier such that the translational movement of the dressing device changes the distance between the dressing device and the first axis of rotation. In other words, the translational movement of the dressing device may be orthogonal to the first axis of rotation. For example, the dressing device may be moved 100 mm to 200 mm, preferably 125 mm to 175 mm, particularly preferably 150 mm, relative to the carrier, in particular away from the carrier. Advantageously, this has the effect that collisions with the gripping device can be effectively prevented. Additionally or independently, by spacing the dressing device from the carrier, the soiling of the gripping device due to wear caused, for example, by dressing an abrasive material, can be significantly reduced.

[0038] Alternatively or additionally, the dressing device may be rotationally movable relative to the carrier. For example, the dressing device may be pivotable about a pivot axis of the dressing device relative to the carrier. The pivot axis of the dressing device may be arranged parallel to the first axis of rotation. If the dressing device may be translationally and rotationally movable relative to the carrier, the translational movement of the dressing device may change the distance between the pivot axis of the dressing device and the first axis of rotation.

[0039] The embodiment having the dressing device movable relative to the carrier advantageously means that the dressing device can be particularly well positioned relative to the abrasive material. This has the advantage that the abrasive material can be dressed particularly precisely by the dressing device.

[0040] In another exemplary embodiment, the apparatus includes a profiling device. The profiling device can be designed for profiling, in particular for pre-profiling, the abrasive material of the grinding device. For example, the profiling device can have a rotating cutting edge, past which the abrasive material can be rotated to introduce a profile into the abrasive material. Preferably, the profiling device is arranged on the gripping device, in particular on the drive ring, or on the base body of the gripping device. Such an arrangement of the profiling device advantageously means that the profiling device can be axially movable relative to the second axis of rotation and / or can be pivoted about the second axis of rotation. This has the advantage that the profiling device can be particularly well positioned relative to the abrasive material.

[0041] In another exemplary embodiment, the apparatus comprises a centering device. The centering device can be designed to align, in particular center, the workpiece with respect to another component of the apparatus and / or with respect to a component of the machine tool. For example, the centering device may be provided to align, in particular center, the workpiece with respect to the workpiece spindle. The centering device can additionally or alternatively be designed to support the workpiece. For example, the centering device can support the workpiece when it is driven by the workpiece spindle. The centering device is preferably a tailstock. The embodiment with the centering device has the advantage that the machine tool can be loaded very accurately by the device and / or the workpiece can be held in place during machining. This increases the accuracy of the machine tool in particular. Advantageously, manufacturing tolerances on the workpiece can be minimized.

[0042] The apparatus may have a position determining device. The position determining device is preferably designed to detect the position of the workpiece, in particular at least one tooth space of the workpiece. For example, the position determining device detects the position of the workpiece after it has been loaded into the machine tool. Alternatively or additionally, the position determining device detects the position of the workpiece after it has been placed on the workpiece spindle by the gripping device. In particular, the position determining device can be designed to determine the position of a tooth flank or a tooth space of the workpiece. Alternatively or additionally, the position determining device can be designed to determine the position of the gripping arm, in particular the position of the gripping arm relative to the second axis of rotation.

[0043] To determine the respective positions, the position determination device can comprise at least one sensor. The sensor can be an optical and / or electromagnetic sensor, in particular a distance sensor. The sensor can be, for example, a Hall sensor. The detection of the position of the workpiece by the position determination device has the advantage of improving the precision of the machine tool. For example, the abrasive material of the grinding device of the machine tool can be better aligned with the workpiece according to the determined position of the workpiece, so that the tolerances of the workpiece are regularly distributed over the circumference and the manufacturing tolerances on the workpiece can be minimized. In particular, the position determination device can be used to determine the position of the workpiece in such a way that it is ensured that the abrasive material does not collide when it comes into contact with the tooth tip of the workpiece.

[0044] According to the invention, the problem stated at the outset is also solved by a machine tool for gear grinding of workpieces, in particular for hard precision machining of pre-toothed workpieces such as gear blanks. For this purpose, the machine tool comprises a machine housing, a grinding device and an apparatus as described above. According to the invention, the grinding device is arranged on the machine housing and is designed to grind the workpieces. The machine housing of the machine tool forms a base for the apparatus according to the above-mentioned embodiment.

[0045] The machine tool according to the invention has the advantage that the workpieces can be loaded and unloaded more quickly by the device on the machine tool. In addition to that, or independently of that, the carrier which is rotatable about the first axis of rotation has the effect of improving the accessibility of the individual components of the machine tool. This has the advantage that the machine tool according to the invention is easier to maintain.

[0046] In a first exemplary embodiment, the machine tool comprises a dressing device arranged on the carrier and a workpiece spindle arranged on the carrier. The dressing device can be designed for dressing the abrasive of the grinding device, in particular for profiling and / or regrind. Preferably, the dressing device is arranged radially offset on the carrier with respect to the first axis of rotation. This has the effect that, for example, the dressing device pivots about the first axis of rotation when the carrier rotates, for example, about the first axis of rotation. The dressing device can be arranged on the carrier so that it can move, in particular so that it can move translationally and / or rotationally. Preferably, the dressing device is arranged on the side of the carrier opposite the workpiece spindle. For example, the dressing device is arranged on the carrier in a position offset by 180° with respect to the workpiece spindle with respect to the first axis of rotation.

[0047] The workpiece spindle is preferably designed to rotate the workpiece arranged on the workpiece spindle. Advantageously, the gripping device is designed to load and unload the workpiece on the workpiece spindle. The workpiece spindle can be rotatable about a third axis of rotation, in particular about a third axis of rotation. Preferably, the third axis of rotation is offset parallel to the first axis of rotation. This has the effect that when the carrier rotates about the first axis of rotation, for example, the workpiece spindle pivots about the first axis of rotation.

[0048] The carrier can rotate about a first axis of rotation such that the carrier can rotate between a grinding position and a maintenance position. Preferably, the workpiece spindle faces towards the grinding device in the grinding position. This advantageously means that the workpiece can be machined on the workpiece spindle by the grinding device in the grinding position. In the maintenance position, the dressing device can face towards the grinding device. Advantageously, this means that the abrasive of the grinding device can be maintained by the dressing device in the maintenance position.

[0049] The machine tool according to the first embodiment has the advantage that it is easy for the user to handle and maintain. Additionally or alternatively, the workpiece spindle and / or the gripping device may be more easily, in particular freely, accessible to a user in the access position. The access position of the carrier may correspond to a maintenance position of the carrier.

[0050] In an exemplary embodiment, the machine tool has a profiling device in addition to the dressing device. The profiling device can be designed for profiling, in particular for pre-profiling, the abrasive material of the grinding device. For example, the profiling device can have a rotating cutting blade, and the abrasive material can be rotated and passed against the cutting blade in order to create a profile in the abrasive material. The profiling device is preferably arranged on the gripping device. Advantageously, the profiling device faces the grinding device when the carrier is in the maintenance position. In particular, this means that the abrasive material can be pre-profiling and then dressed very quickly one after the other. The pre-profiling is preferably performed by the profiling device and the dressing is performed by the dressing device. This has the advantage that the maintenance operations of the abrasive material can be reduced to a minimum of time.

[0051] According to the invention, the problem mentioned at the beginning is also solved by a method using an apparatus according to the above embodiment. Preferably, the apparatus has a first gripping arm, a second gripping arm and a third gripping arm. A method for loading and unloading a machine tool using such an apparatus has the advantage that the machine tool can be loaded and unloaded with workpieces more quickly, in particular the exchange of several workpieces can be performed more quickly.

[0052] The method for loading and unloading a workpiece on a machine tool can include an initial loading process, i.e., initially loading the workpiece on the machine tool. As part of the initial loading process, the first gripping arm and the second gripping arm are preferably pivoted relative to each other about the second axis of rotation such that the first gripping arm and the second gripping arm assume a gripping position relative to each other to grip the first workpiece. The first gripping arm and the second gripping arm can grip the first workpiece, for example, in a pick-up position. It is conceivable that after the first workpiece is gripped by the first gripping arm and the second gripping arm, the gripping device is moved axially along the second axis of rotation. This can be useful, for example, when the first workpiece is lifted after gripping. During further process steps of the initial loading process, the first gripping arm and the second gripping arm are pivoted synchronously with each other about the second axis of rotation. During the synchronous pivoting process, the first gripping arm and the second gripping arm remain in the gripping position relative to each other. This means that the first workpiece is also pivoted about the second axis of rotation. This allows the first workpiece to be transported from the pick-up position to the loading position. Preferably, the loading position is located on or at the workpiece spindle.

[0053] Optionally, the gripping device can be moved axially along the second axis of rotation after the synchronous pivoting of the first and second gripping arms. This has the advantage that the first workpiece can be lowered or placed, for example, on the workpiece spindle. In the final process step of the initial loading process, the first and second gripping arms are pivoted relative to each other about the second axis of rotation such that the first and second gripping arms assume a release position relative to each other. As a result, the workpiece is released from the first and second gripping arms in the loading position. Preferably, the first and second gripping arms are separated in the final process step of the initial loading process such that the first workpiece can be machined by the grinding device in the loading position, particularly without being disturbed.

[0054] In an exemplary embodiment, the method includes a workpiece exchange process. Preferably, the workpiece exchange process replaces the first workpiece with a second workpiece. For example, the first workpiece may be ground by a machine tool, and may in particular be arranged on a workpiece spindle. For example, the first workpiece on the workpiece spindle must be replaced or exchanged with the second workpiece so that the second workpiece can be subsequently ground.

[0055] At the start of the workpiece exchange process, the second workpiece can be gripped by the second gripping arm and the third gripping arm. For this purpose, the second gripping arm and the third gripping arm can be pivoted relative to each other about the second axis of rotation such that the second gripping arm and the third gripping arm assume a gripping position relative to each other. During a further step of the workpiece exchange process, the first gripping arm and the second gripping arm can be pivoted relative to each other about the second axis of rotation such that the first gripping arm and the second gripping arm change relative to each other from a release position to a gripping position. For example, the first gripping arm and the second gripping arm can grip the first workpiece by changing from the release position to the gripping position.

[0056] The third gripping arm is preferably pivoted about the second axis of rotation such that the third gripping arm synchronously follows the second gripping arm, whereby advantageously the second gripping arm and the third gripping arm remain in a gripping position relative to each other and the second workpiece follows the movements of the second gripping arm and the third gripping arm.

[0057] This method means that the second workpiece can be provided right next to the first workpiece. Advantageously, this means that the gripper arm only needs to be pivoted a small amount, for example within a pivot range of <90°, preferably within a pivot range of <45°, to actually exchange the two workpieces. Such a small pivot range has the advantage of ensuring that the workpieces can be quickly and effectively exchanged during the workpiece exchange process.

[0058] If the first workpiece is gripped by the first gripping arm and the second gripping arm and the second workpiece is gripped by the second gripping arm and the third gripping arm, a transport operation can be performed as part of the workpiece exchange process, as will be explained in more detail below. During the transport operation, the first gripping arm, the second gripping arm and the third gripping arm are preferably pivoted synchronously with each other about the second axis of rotation, such that the first workpiece and the second workpiece are also pivoted synchronously with each other about the second axis of rotation. Preferably, the second gripping arm is used on both sides during the transport operation. This means that the second gripping arm is in contact with the first workpiece on the side facing towards the first gripping arm and with the second workpiece on the side facing towards the third gripping arm. The advantage of this is that as many workpieces as possible can be transported at once with the fewest possible number of gripping arms. This has the advantage that the workpieces are transported particularly efficiently.

[0059] In a further step of the workpiece exchange process, the second workpiece can be released in the loading position. For this purpose, the second gripping arm and the third gripping arm are pivoted relative to each other about the second axis of rotation such that the second gripping arm and the third gripping arm assume a release position relative to each other. The first workpiece can be transported to the storage position by synchronously pivoting the first gripping arm and the second gripping arm about the second axis of rotation. Subsequently, the first gripping arm and the second gripping arm can be pivoted relative to each other about the second axis of rotation such that the first gripping arm and the second gripping arm assume a release position relative to each other, releasing the first workpiece in the storage position.

[0060] Preferably, the method for loading and unloading a machine tool includes multiple workpiece exchange processes. In particular, the method can include a first workpiece exchange process and a second workpiece exchange process. For example, during the first workpiece exchange process, the first workpiece can be replaced with the second workpiece. This process is as described above.

[0061] During the first workpiece exchange process, the second gripping arm is preferably pivoted in a first pivot direction about the second axis of rotation, in particular during a transfer operation as part of the first workpiece exchange process, the second gripping arm is pivoted in a first pivot direction about the second axis of rotation.

[0062] Similar to the first workpiece exchange process, the second workpiece can be replaced with a third workpiece during the second workpiece exchange process. During the second workpiece exchange process, the second gripping arm can be pivoted in a second pivot direction about the second rotation axis. The second pivot direction is preferably opposite to the first pivot direction. In other words, the first and second pivot directions are preferably opposite to each other. For example, the second gripping arm is pivoted in a second pivot direction about the second rotation axis during a transfer operation as part of the second workpiece exchange process. Advantageously, this has the effect that the machine tool, in particular the workpiece spindle of the machine tool, can be loaded and unloaded from different directions, for example from the left and from the right. Such a method has the advantage that a faster and more effective exchange of the workpiece is ensured.

[0063] In an exemplary further development of the above-mentioned two embodiments of the method for loading and unloading a machine tool, the second gripping arm and the third gripping arm can be pivoted relative to each other about the second axis of rotation during the second workpiece exchange process such that the second gripping arm and the third gripping arm change relative to each other from a release position to a gripping position. For example, the second gripping arm and the third gripping arm can grip the second workpiece by changing from a release position to a gripping position. Alternatively, the second gripping arm and the third gripping arm can be pivoted relative to each other about the second axis of rotation during the workpiece exchange process such that the second gripping arm and the third gripping arm change relative to each other from a gripping position to a release position, for example to release the workpiece between the second gripping arm and the third gripping arm.

[0064] Regardless of whether the second and third gripping arms change from a release position to a gripping position or whether the second and third gripping arms change from a gripping position to a release position, the first gripping arm is preferably pivoted about the second axis of rotation during the second workpiece exchange process such that the first gripping arm synchronously follows the second gripping arm. Advantageously, this means that, for example, when the first and second gripping arms take a gripping position relative to each other and a third workpiece is placed between the first and second gripping arms, the third workpiece follows the movement of the second gripping arm. The advantage of such a method is that it is ensured that the second workpiece exchange process allows the workpiece to be exchanged quickly and effectively.

[0065] In another exemplary embodiment, the method includes a transport operation. The transport operation already indicated in the above description can be applied for two workpieces transported simultaneously. This can be particularly advantageous in the context of a workpiece exchange process. During the transport operation, for example, a first workpiece can be transported, in particular from a loading position, and at the same time, a second workpiece can be transported, in particular to a loading position. For example, during the transport operation, the first workpiece can be transported from the workpiece spindle and the second workpiece can be transported towards the workpiece spindle. Preferably, the first workpiece is arranged between the first gripping arm and the second gripping arm during the transport operation, the first gripping arm and the second gripping arm taking a gripping position relative to each other. Furthermore, the second workpiece can be arranged between the second gripping arm and the third gripping arm, the second gripping arm and the third gripping arm taking a gripping position relative to each other. In other words, the second gripping arm is preferably disposed between the first workpiece and the second workpiece during the conveying operation. To convey the workpieces, the first gripping arm, the second gripping arm and the third gripping arm can be pivoted synchronously with each other about the second axis of rotation. As a result, the workpieces are conveyed synchronously, in particular pivoted about the second axis of rotation at the same time.

[0066] The different exemplary features described above can be combined with one another in accordance with the present invention, wherever technically reasonable and appropriate. Further features, advantages and embodiments of the present invention are illustrated in the following description of exemplary embodiments, with reference to the drawings. The drawings show: [Brief description of the drawings]

[0067] [Figure 1] 1 is a perspective view of one embodiment of a grinding machine having an apparatus for loading and unloading the grinding machine; [Diagram 2] 2 is a perspective view of a gripping device according to an embodiment of the device for loading and unloading the grinding machine shown in FIG. 1; [Diagram 3]3 is a detail of a cross-sectional view of the gripping device shown in FIG. 2 . [Figure 4] 3 is a detail of another cross-sectional view of the gripping device shown in FIG. 2 . [Diagram 5] 2 shows a second embodiment of the gripping device. [Figure 6] FIG. 2 is a top view of the embodiment according to FIG. 1 during the initial loading process. [Figure 7] 2 is a top view of the embodiment according to FIG. 1 at the start of the workpiece exchange process; [Figure 8] 2 shows a top view of the embodiment according to FIG. 1 at the start of a transfer operation as part of a workpiece exchange process; [Figure 9] FIG. 2 is a top view of the embodiment according to FIG. 1 in a maintenance position or in a position for storing the workpieces at the operator's side. [Figure 10] FIG. 2 is a cross-sectional view of a portion of the embodiment according to FIG. [Figure 11] FIG. 13 is a perspective view of a portion of another embodiment of a grinding machine having a device for loading and unloading the grinding machine. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0068] 1 shows a perspective view of an embodiment of a grinding machine 30 having a device 1 for loading and unloading the grinding machine 30, in particular for loading and unloading a workpiece 40 therein. In the embodiment shown, the grinding machine 30 is a gear grinding machine 30. The gear grinding machine 30 is designed for machining, in particular for grinding, a workpiece 40. The workpiece 40 may be a pre-toothed workpiece 40, in particular a gear blank 40.

[0069] The grinding machine 30 shown here diagrammatically comprises a grinding device 32 with an abrasive material 33 for grinding a workpiece 40. The abrasive material 33 is, for example, a grinding worm 33. The grinding device 32 is arranged on a machine housing 31. The machine housing 31 also forms a base 2 for a device 1 for loading and unloading the grinding machine 30.

[0070] The device 1 for loading and unloading a grinding machine 30 comprises a carrier 3 and a gripping device 11 . The carrier 3 is connected to the base 2 and has a first vertical axis of rotation D 1 The carrier tower 4 of the carrier 3 is rotatable relative to the base 2 about a first rotation axis D. 1 and has an outer side surface 5. 2 extends into the carrier tower 4 in the illustrated embodiment and has a first axis of rotation D 1 is offset parallel to

[0071] A dressing device 6 is arranged on the carrier 3. The dressing device 6 is designed for dressing the abrasive material 33 of the grinding device 32, in particular for profiling and / or regrinding the abrasive material 33. Furthermore, a workpiece spindle 7 is arranged on the carrier 3. The workpiece spindle 7 is oriented about a third axis of rotation D 3 The workpiece spindle 7 is rotatable relative to the carrier about a third axis of rotation D 3 , in particular when a workpiece 40 is placed on the workpiece spindle 7.

[0072] The gripping device 11 is arranged on the carrier 3, in particular on the carrier tower 4, and is movable along the outer surface 5 of the carrier tower 4. In other words, the gripping device 11 is arranged on the carrier 3, in particular on the carrier tower 4, in such a way that the gripping device 11 is movable along the outer surface 5 of the carrier tower 4. 2 The gripping device 11 is designed to grip and release the workpiece 40.

[0073] The gripping device 11 has a first gripping arm 13, a second gripping arm 14, and a third gripping arm 15. Each of the gripping arms 13, 14, 15 is oriented about a second axis of rotation D independently of the other gripping arms 13, 14, 15. 2The gripping arms 13, 14, 15 are arranged in a sequence such that the second gripping arm 14 is always located between the first gripping arm 13 and the third gripping arm 15, and is pivotable about the second axis of rotation D. 2 is determined in the circumferential direction.

[0074] A gripping means 21 is arranged on each of the first and third gripping arms 13, 15. In the illustrated embodiment example, two gripping means 21 are arranged on the central second gripping arm 14. In each case, the gripping means 21 are arranged on the gripping arms 13, 14, 15 such that the gripping means 21 of the outer gripping arms 13, 15 can interact with the gripping means 21 of the central gripping arm 14 facing it. Each gripping means 21 comprises an upper part and a lower part, and the corresponding gripping arm 13, 14, 15 is arranged between the upper part and the lower part. Preferably, the upper part and the lower part of each gripping means 21 are connected to each other via a pin extending through the corresponding gripping arm 13, 14, 15. The gripping means 21 are fixedly connected to the respective gripping arm 13, 14, 15. Preferably, the connection between the gripping means 21 and the respective gripping arm 13, 14, 15 is removable to allow replacement of the gripping means 21. Both the upper and lower parts of the gripping means 21 form gripping jaws having an inner contour in the shape of a circular ring section, the diameter of which is adapted to the diameter of the workpiece 40 to be gripped.

[0075] Each gripping arm 13, 14, 15 is disposed on a drive ring 16, 17, 18 (see also FIG. 2). In the illustrated embodiment, the first gripping arm 13 is disposed on the first drive ring 16, the second gripping arm 14 is disposed on the second drive ring 17, and the third gripping arm 15 is disposed on the third drive ring 18. The drive rings 16, 17, 18 are each oriented around a second axis of rotation D 2 The connection between the drive rings 16, 17, 18 and the corresponding gripping arms 13, 14, 15 is such that each drive ring 16, 17, 18 is rotated about a second axis of rotation D. 2 When rotating about the second axis of rotation D, the corresponding gripping arms 13, 14, 15 rotate about the second axis of rotation D.2 The hub is designed to pivot about the axis of rotation.

[0076] The gripping device 11 comprises a drive mechanism 23 designed to drive the gripping arms 13, 14, 15 independently of one another. The drive mechanism 23 comprises a number of drive means 24, 25, 26, in particular a first drive means 24, a second drive means 25 and a third drive means 26, each of which drives a drive ring 16, 17, 18.

[0077] FIG. 2 shows a perspective view of the gripping device 11 according to the embodiment of FIG. As can be seen in Fig. 2, the workpiece 40 is gripped by the first gripping arm 13 and the second gripping arm 14. For this purpose, the first gripping arm 13 and the second gripping arm 14 are rotated about a second axis of rotation D such that the first gripping arm 13 and the second gripping arm 14 are in a gripping position relative to each other. 2 is pivoted about the center.

[0078] The workpiece 40 is contacted by a gripping means 21 arranged on the first gripping arm 13 and by a gripping means 21 arranged on the second gripping arm 14. The gripping means 21 cooperate to apply a clamping force to the workpiece 40. Furthermore, the gripping means 21 each have a protrusion 22, as can be seen on the gripping means 21 of the third gripping arm 15. By means of the protrusion 22 the workpiece can be gripped by the gripping means 21 from below.

[0079] In the position shown in Fig. 2, the second gripping arm 14 and the third gripping arm 15 assume a release position relative to each other. In the release position, the second gripping arm 14 and the third gripping arm 15 are apart and in particular aligned with the second axis of rotation D such that no workpiece can be gripped by the second gripping arm 14 and the third gripping arm 15. 2The distance between the second gripping arm 14 and the third gripping arm 15 is such that no clamping force can be applied to the workpiece via the gripping means 21. In addition, the distance between the second gripping arm 14 and the third gripping arm 15 is selected such that the workpiece cannot be gripped from below by the protrusions 22.

[0080] The drive rings 16, 17, 18 are aligned along a second axis of rotation D 2 axially next to each other, in particular one above the other. The base body 12 of the gripping device 11 axially limits the drive rings 16, 17, 18.

[0081] FIG. 3 shows the arrangement of the drive rings 16, 17, 18 as a detail of a vertical section of the gripping device 11. The section of FIG. 3 is taken along the second axis of rotation D. 2 was chosen to run parallel to The drive rings 16, 17, 18 are rotatably mounted relative to one another via roller bearings 19. The two outer drive rings, in particular the first drive ring 16 and the third drive ring 18, are each supported axially outwardly via roller bearings 19 on the base body 12 of the gripping device 11. The bearings shown in FIG. 3 act like angular contact ball bearings, so that axial and radial forces can be transmitted via the roller bearings 19.

[0082] The drive rings 16, 17, 18 are circular in the embodiment described herein. In alternative embodiments, the drive rings 16, 17, 18 may be semi-circular or part-circular. As shown in FIG. 3 by way of example of second gripping arm 14 and second drive ring 17, gripping arms 13, 14, 15 are arranged on drive ring 16 radially outwardly on drive rings 16, 17, 18.

[0083] Each of the drive rings 16, 17, 18 has internal teeth 20 on its inner surface. FIG. 4 shows, for example, the internal teeth 20 of the first drive ring 16 as a detail of a horizontal section of the gripping device 11. For better understanding, the second axis of rotation D2 A cross section through the gripping device 11 perpendicular to the was chosen for the cross section of FIG.

[0084] As already mentioned above, each gripping arm 13, 14, 15 is driven by a corresponding drive ring 16, 17, 18. The drive rings 16, 17, 18 are in turn driven by drive means 24, 25, 26, respectively, of the drive mechanism 23. The cross-sectional view shown in FIG. 4 shows the drive shaft of the first drive means 24, which is non-rotatably connected to a spur gear 27. The spur gear 27 is rotatably mounted in the base body 12 of the gripping device 11. The spur gear 27 has external teeth 28 which engage with the internal teeth 20 of the first drive ring 16. As a result of this engagement, when the spur gear 27 is driven by the drive means 24, the rotational movement of the spur gear 27 rotates the drive ring 16 along the second axis of rotation D. 2 Accordingly, the first gripping arm 13 arranged on the first drive ring 16 also rotates about the second axis of rotation D 2 It is pivoted about the center.

[0085] The drive of the drive ring 16 described by way of example in figure 4 can be applied analogously to all other drive rings 17, 18. Thus, the second drive ring 17 is driven by second drive means 25 and the third drive ring 18 is driven by third drive means 26.

[0086] 5 shows a second exemplary embodiment of the gripping device 11. The structure of the gripping device 11 according to the second embodiment corresponds in principle to the structure of the gripping device 11 according to the first embodiment. The only difference between the two embodiments of the gripping device 11 is that the gripping device 11 in the second embodiment comprises a position determination device 9 .

[0087] The position determination device 9 comprises two sensors 10a, which are respectively arranged on the second gripping arm 14. The sensors 10a are positioned on the second gripping arm 14 such that the sensors 10a respectively face towards the workpiece 40 when the second gripping arm 14 is in a gripping position with the first gripping arm 13 and / or the third gripping arm 15 and the workpiece 40 is arranged between the respective gripping arms.

[0088] 5, the second gripping arm 14 is in a gripping position with the first gripping arm 13, with a workpiece 40 disposed between the second gripping arm 14 and the first gripping arm 13. The second gripping arm 14 and the third gripping arm 15 are in a release position relative to each other, so that no workpiece 40 is disposed between the second gripping arm 14 and the third gripping arm 15.

[0089] The sensors 10a can be optical and / or electromagnetic sensors 10a, in particular Hall sensors. Preferably, the sensors 10a are designed to determine the position of the corresponding workpiece 40, in particular the rotational angular position of the corresponding workpiece 40. The position determination can be performed by means of the tooth flanks of the workpiece 40.

[0090] For example, starting from the gripping position shown in Figure 5, the first gripping arm 14 and the second gripping arm 15 may be moved to a release position such that the workpiece 40 can be rotated by the workpiece spindle 7, but the sensor 10a still faces the workpiece 40. This allows the sensor 10a to detect the teeth of the workpiece 40 as it rotates past the sensor 10a.

[0091] The position determination device 9 further comprises a sensor 10b designed to determine the position of the respective gripping arm 13, 14, 15 and / or the position of a workpiece 40 arranged between the respective gripping arms 13, 14, 15. Alternatively or additionally, the sensor 10b may be designed to determine the position of the workpiece 40 arranged in front of the sensor 10b, in particular the rotational angular position of the workpiece 40 arranged in front of the sensor 10b. The sensor 10b may be an optical and / or electromagnetic sensor 10b.

[0092] Alternatively, the position determination of the gripping arms 13, 14, 15 can be performed via the drive means 24, 25, 26. This is particularly advantageous if the drive means 24, 25, 26 are synchronous motors 24, 25, 26. For example, the position of the gripping arms 13, 14, 15 can be determined on the basis of the number of rotation steps performed in each case by the synchronous motors 24, 25, 26.

[0093] Figure 6 shows a top view of the grinding machine 30 according to Figure 1. With regard to the particular construction of the grinding machine 30, the device 1 for loading and unloading the grinding machine 30 and in particular the gripping device 11, reference is made to the above description. In contrast to Figure 1, a fourth axis of rotation D4 is visible in Figure 6.

[0094] The abrasive material 33 of the grinding device 32 is designed to rotate about a fourth axis of rotation D4. In the embodiment shown in Fig. 6, the device 1 for loading and unloading a grinding machine 30 is in an initial loading process. In other words, Fig. 6 shows the device 1 in a state that occurs when the device 1 loads a grinding machine 30 for the first time in a processing cycle. This can be recognized by the absence of a workpiece on the workpiece spindle 7 and no workpiece being arranged between the second gripping arm 14 and the third gripping arm 15. The second gripping arm 14 and the third gripping arm 15 are in a release position relative to each other. The first gripping arm 13 and the second gripping arm 14 are in a gripping position relative to each other and jointly grip a first workpiece 40 provided, for example, lying on a belt conveyor.

[0095] Following the position shown in FIG. 6, the first workpiece 40 is transferred to the workpiece spindle 7. To lift the first workpiece 40, the gripping device 11 is aligned with the second axis of rotation D 2 Independently, the first workpiece 40 can be moved axially along the second rotation axis D towards the viewer by the first gripping arm 13 and the second gripping arm 14 until the first workpiece 40 is positioned above the workpiece spindle 7. 2 In the illustrated example, the pivot angle is 180°. The first gripping arm 13 and the second gripping arm 14 are pivoted clockwise about the second axis of rotation D. 2 Optionally, the gripping device 11 is then pivoted synchronously about a second axis of rotation D to place the first workpiece 40 on the workpiece spindle 7. 2 To complete the initial loading process, the first gripping arm 13 and the second gripping arm 14 can each be moved axially again along the second axis of rotation D 2 , whereby the first gripping arm 13 and the second gripping arm 14 assume a release position relative to each other and release the first workpiece 40, in particular the first workpiece 40 on the workpiece spindle 7.

[0096] FIG. 7 shows the grinding machine 30, in particular the device 1, after completion of the initial loading process. This can be recognized by the fact that a first workpiece 40 is placed on the workpiece spindle 7. Furthermore, the first gripping arm 13 and the second gripping arm 14 are in a release position relative to each other. The first gripping arm 13 and the second gripping arm 14 are spaced apart such that the first workpiece 40 can be processed by the grinding device 32, in particular by the abrasive material 33, without being disturbed. The first gripping arm 13 and the second gripping arm 14 are pivoted relative to each other about the second axis of rotation such that the distance between the first gripping arm 13 and the second gripping arm 14 is greater than the axial width of the abrasive material 33.

[0097] The second gripping arm 14 and the third gripping arm 15 are also in a release position relative to each other. A second workpiece 41 is provided by the conveyor belt 34. As part of the workpiece exchange process, the second gripping arm 14 and the third gripping arm 15 are rotated around the second rotation axis D, starting from the position shown in FIG. 7, so that the second gripping arm 14 and the third gripping arm 15 are in a gripping position relative to each other and grip the second workpiece 41 in the process. 2 When the second workpiece 41 is gripped by the second gripping arm 14 and the third gripping arm 15, the gripping device 11 is pivoted about the second rotation axis D to lift the second workpiece 41. 2 , and particularly toward the viewer.

[0098] During the workpiece exchange process, the second workpiece 41 is gripped by the second gripping arm 14 and the third gripping arm 15 along the second axis of rotation D until it is positioned next to the first workpiece 40 in the circumferential direction. 2 For this purpose, the second gripping arm 14 and the third gripping arm 15 are pivoted clockwise about the second axis of rotation D 2 Optionally, the second rotation axis D of the gripping device 11 is 2, and in particular axial movement away from the viewer.

[0099] During these steps, machining of the first workpiece 40 can continue. The position of the device 1, in particular the gripping device 11, shown in Fig. 8 is an intermediate position in the workpiece exchange process. To reach this position, the first gripping arm 13 and the second gripping arm 14 are rotated relative to the second axis of rotation D such that, after completion of the machining of the workpiece 40, the first gripping arm 13 and the second gripping arm 14 take up the gripping position relative to each other and grip the first workpiece 40. 2 The third gripping arm 15 is pivoted relative to the second gripping arm 14 about the second axis of rotation D. 2 and in particular, the second gripping arm 14 is pivoted about a second axis of rotation D 2 In other words, the second gripping arm 14 and the third gripping arm 15 remain in the gripping position independent of the movement of the second gripping arm 14. The second workpiece 41 remains between the second gripping arm 14 and the third gripping arm 15.

[0100] As part of the workpiece exchange process, the position shown in FIG. 8 is preferably followed by a transport operation. During the transport operation, in particular, the first workpiece 40 is transported away from the workpiece spindle 7 and the second workpiece 41 is transported towards the workpiece spindle 7. Preferably, the first workpiece 40 remains between the first gripping arm 13 and the second gripping arm 14 during the transport operation. The same is true for the second workpiece 41 between the second gripping arm 14 and the third gripping arm 15. In other words, the first gripping arm 13 and the second gripping arm 14 remain in a gripping position relative to each other during the transport operation. The second gripping arm 14 and the third gripping arm 15 also remain in a gripping position relative to each other during the transport operation. To transport the workpieces 40, 41, the first gripping arm 13, the second gripping arm 14 and the third gripping arm 15 are rotated in a direction parallel to the second axis of rotation D. 2can be pivoted synchronously with each other about the center.

[0101] Preferably, the first gripping arm 13, the second gripping arm 14 and the third gripping arm 15 are pivoted clockwise about the second axis of rotation D2 synchronously with one another, so that the workpieces 40, 41 are conveyed synchronously, in particular at the same time, around the second axis of rotation D 2 is pivoted clockwise about the axis.

[0102] 9 shows the grinding machine 30 in a maintenance position, in particular the device 1 for loading and unloading the grinding machine 30. In the embodiment shown, a maintenance access for the grinding machine 30, which allows a user to access the components of the grinding machine 30, is located at the bottom end of FIGS. 6-9. This access can also be used for manually loading the grinding machine 30 with a workpiece.

[0103] To move the device 1 into a maintenance position, the carrier 3 is rotated relative to the machine housing 31 or relative to the base 2 along a first axis of rotation D 1 The gripping device 11 was rotated 90° clockwise around the first rotation axis D. 1 As a result, the gripping device 11 is positioned at the maintenance access point and is accessible to the user. Also, the carrier 3 is pivoted 90° clockwise about the first rotation axis D. 1 It is also conceivable that the carrier 3 may further rotate about the first axis of rotation D, for example so that the dressing device 6 is positioned at a maintenance access point or is accessible to a user. 1 so that the workpiece spindle 7 is positioned at a maintenance access point or can be accessed by a user.

[0104] FIG. 10 shows a cross-sectional view of a part of a grinding machine 30, i.e. a part of the device 1. As shown in the illustration of FIG. 10, the dressing device 6 is arranged at the lower end of the carrier tower 4 of the carrier 3. The dressing device 6 can be translated in a moving direction R indicated by the arrow. This means that the dressing device 6 can be moved in a translational manner relative to the carrier 3 or relative to a first axis of rotation D, not shown in FIG. 10. 1 The translational movement is relative to the first axis of rotation D 1 is perpendicular to

[0105] Independently of this, the dressing device is pivotable about a pivot axis S. The pivot axis S is aligned with the first axis of rotation D. 1 Parallel to the axis of rotation D 1 The translational and rotational movements of the dressing device 6 allow the dressing device 6 to be aligned particularly precisely with respect to the abrasive material 33 in the maintenance position. As a result, the dressing of the abrasive material 33 can be performed particularly precisely.

[0106] 11 shows a perspective view of a part of a further embodiment of a grinding machine 30 with a device 1 for loading and unloading the grinding machine 30. The further embodiment shown in FIG. 11 differs from the previous embodiment only in that the device 1 of the further embodiment has a profiling device 29.

[0107] The profiling device 29 is attached to the base 12 of the gripping device 11. The profiling device 29 is preferably arranged on the gripping device 11 in such a way that when the device 1, in particular the carrier 3 not shown in FIG. 11, is in the maintenance position, the profiling device 29 faces the abrasive material 33 of the grinding device 32. FIG. 11 shows the device 1 in the maintenance position. To profiling the abrasive material 33, the abrasive material 33 is rotated about the fourth rotation axis D4 and moved towards the profiling device 29. As a result, material is removed from the abrasive material 33 by the profiling device 29, and thus the abrasive material 33 is profiling processed.

Claims

1. An apparatus (1) for loading and unloading a workpiece (40, 41) on a machine tool (30) for machining gears, in particular a hard precision machining machine (30), said apparatus (1) comprising: (a) a base (2); (b) a first rotation axis (D) disposed on the base (2) and aligned with respect to the base (2); １ A carrier (3) rotatable about a center of gravity (G); (c) a gripping device (11) arranged on said carrier (3) for gripping and releasing said workpieces (40, 41); Equipped with (d) The gripping devices (11) each have a second rotation axis (D ２ at least two gripping arms (13, 14, 15) that are pivotable independently of one another about a pivot point; (d1) the gripping arms (13, 14, 15) are rotated relative to each other along the second axis of rotation (D) so that the gripping arms (13, 14, 15) can take a gripping position for gripping the workpieces (40, 41) and a release position for releasing the workpieces (40, 41). ２ ) relative to each other, (d2) The gripping arms (13, 14, 15) are synchronous with each other at least at the gripping position and rotate along the second axis of rotation (D ２ ).

2. 2. The apparatus (1) according to claim 1, characterized in that a workpiece spindle (7) for rotating the workpieces (40, 41) is arranged on the carrier (3), and the gripping device (11) is designed for loading and unloading the workpieces (40, 41) onto the workpiece spindle (7).

3. The gripping device (11) is aligned along the second axis of rotation (D ２ 3. The device (1) according to claim 1 or 2, characterized in that it is axially movable along the axis of the shaft.

4. The second rotation axis (D ２ ) is the first rotation axis (D １ 4. The device (1) according to claim 1, characterized in that the rotation of the rotor 1 is parallel to the rotation of the rotor 1.

5. Apparatus (1) according to any one of claims 1 to 4, characterized in that the gripping device (11) is designed to grip or release a workpiece (40, 41) independently of the position and / or rotational movement of the carrier (3).

6. 6. Apparatus (1) according to any one of claims 1 to 5, characterized in that the gripping device (11) comprises a drive mechanism (23) designed to drive the gripping arms (13, 14, 15) independently of one another.

7. 7. The device (1) according to claim 6, characterized in that the drive mechanism (23) comprises a plurality of drive means (24, 25, 26), preferably a plurality of synchronous motors (24, 25, 26), each drive means (24, 25, 26), preferably each synchronous motor (24, 25, 26), assigned to a respective gripping arm (13, 14, 15).

8. Each gripping arm (13, 14, 15) is in each case aligned with said second axis of rotation (D ２ Each of the gripping arms (13, 14, 15) is arranged on a drive ring (16, 17, 18) that is rotatable about a second axis of rotation (D ２ ) when rotating about the second axis of rotation (D ２ 8. The device (1) according to claim 1, characterized in that it is pivoted about a pivot point (11).

9. Device (1) according to claim 8 in combination with claim 7, characterized in that each drive ring (16, 17, 18) has internal teeth (20) and each drive means (24, 25, 26) has a spur gear (27) with external teeth (28) which engage with the internal teeth (20) of the corresponding drive ring (16, 17, 18) to drive the gripping arms (13, 14, 15) arranged on said drive rings (16, 17, 18).

10. 10. Apparatus (1) according to any one of claims 1 to 9, characterized in that at least one gripping means (21) is arranged on each of the gripping arms (13, 14, 15), the gripping means (21) being designed to apply a clamping force to the workpiece (40, 41) in the gripping position and / or having a protrusion (22) for gripping under the workpiece (40, 41).

11. 11. Apparatus (1) according to any one of claims 1 to 10, characterized in that the gripping device (11) is designed such that several workpieces (40, 41) can be gripped simultaneously by the gripping device (11).

12. The gripping device (11) comprises a first gripping arm (13), a second gripping arm (14) and a third gripping arm (15), and the second gripping arm (14) is disposed between the first gripping arm (13) and the third gripping arm (15) along the second axis of rotation (D ２ 12. The device (1) according to claim 1, characterized in that the axial direction of the rotor is axially aligned.

13. The gripping device (11) includes the second gripping arm (14), capable of assuming a gripping or release position relative to said first gripping arm (13); and 13. Device (1) according to claim 12, characterized in that it is designed to be able to assume a gripping position or a release position with respect to the third gripping arm (15).

14. The carrier (3) is rotated along the first axis of rotation (D) so that the carrier (3) can be rotated between an operating position in which the machine tool (30) can be loaded and unloaded with the workpieces (40, 41) by the device, and a maintenance position in which the machine tool (30) and / or the device (1) can be maintained and / or manually loaded. １ 14. The device (1) according to any one of claims 1 to 13, characterized in that it is rotatable about a center axis.

15. The apparatus (1) according to any one of claims 1 to 14, characterized in that the carrier (3) has a vertically arranged carrier tower (4) and the gripping device (11) is arranged on the outer side (5) of the carrier tower (4).

16. 16. Apparatus (1) according to any one of the preceding claims, characterized in that a dressing device (6) for dressing an abrasive material (33) of the machine tool (30) is arranged on the carrier (3).

17. 17. Apparatus (1) according to claim 16, characterized in that the dressing device (6) is movable, preferably translationally and / or rotationally, relative to the carrier (3).

18. 18. The apparatus (1) according to claim 1, characterized in that a profiling device (29) for pre-profiling an abrasive material (33) of the machine tool (30) is arranged on the carrier (3).

19. Apparatus (1) according to any one of claims 1 to 18, characterized in that the apparatus (1) comprises a centering device (8), preferably a tailstock (8), for centering the workpiece (40, 41), preferably on the workpiece spindle (7) according to claim 2.

20. The device (1) according to any one of claims 1 to 19, characterized in that the device (1) has a position determining device (9) for determining the position of the workpiece (40, 41), in particular of at least one tooth gap of the workpiece (40, 41), the position determining device comprising at least one sensor (10).

21. A machine tool (30) for gear grinding of a workpiece (40, 41), preferably for hard precision machining of a pre-toothed workpiece (40, 41), said machine tool (30) comprising: A machine housing (31); a grinding device (32) arranged on the machine housing (31) for grinding the workpieces (40, 41); A device (1) for loading the machine tool (30) with workpieces (40, 41) according to any one of claims 1 to 20, The machine housing (31) of the grinding machine (30) is the base (2) of the apparatus (1), a machine tool (30).

22. A dressing device (6) for dressing the abrasive material (33) of the grinding device (32) is disposed on the carrier (3); The workpieces (40, 41) are rotated along a third axis (D ３ A workpiece spindle (7) for rotating about a workpiece axis (3) is arranged on said carrier (3), The carrier (3) is aligned with the first rotation axis (D) so that the carrier (3) can rotate between a grinding position in which the workpiece spindle (7) faces the grinding device (32) and a maintenance position in which the dressing device (6) faces the grinding device (32). １ 22. The machine tool (30) according to claim 21, characterized in that it is rotatable about a center axis.

23. The carrier (3) is aligned with the first rotation axis (D) so that the carrier (3) is in an access position where a user can access the workpiece spindle (7). １ 23. Machine tool (30) according to claim 21 or 22, characterized in that it can rotate around a center of rotation.

24. A method for loading and unloading at least one workpiece (40, 41) on a machine tool (30) by means of a device (1) according to any one of claims 1 to 20, comprising the steps of: The method, wherein the device (1) comprises a first gripping arm (13), a second gripping arm (14) and a third gripping arm (15).

25. During the workpiece exchange process, The first gripping arm (13) and the second gripping arm (14) are rotated about a second axis of rotation (D) such that the first gripping arm (13) and the second gripping arm (14) change relative to each other from a release position to a gripping position or from the gripping position to the release position. ２ ) pivoted relative to each other, The third gripping arm (15) is rotatably supported by the second gripping arm (14) so ​​that the third gripping arm (15) synchronously follows the second gripping arm (14). ２ 25. The method of claim 24, wherein the rotation is pivoted about a center of gravity.

26. The workpiece exchange process is a first workpiece exchange process, and the second gripping arm (14) rotates along the second rotation axis (D ２ ) in a first pivot direction, and the second gripping arm (14) is pivoted about the second rotation axis (D) in a second pivot direction opposite to the first pivot direction during a second workpiece exchange process. ２ 26. The method of claim 25, wherein the rotation is pivoted about a center of gravity.

27. During the second workpiece exchange process, The second gripping arm (14) and the third gripping arm (15) are rotated relative to each other along the second axis of rotation (D) such that the second gripping arm (14) and the third gripping arm (15) change relative to each other from the release position to the gripping position or from the gripping position to the release position. ２ ) pivoted relative to each other, The first gripping arm (13) is rotated along the second axis of rotation (D) so that the first gripping arm (13) synchronously follows the second gripping arm (14). ２ 27. The method of claim 26, wherein the rotation is pivoted about a center of gravity.

28. During the transport operation, a first workpiece (40) is disposed between the first gripping arm (13) and the second gripping arm (14), the first gripping arm (13) and the second gripping arm (14) being in a gripping position relative to each other; a second workpiece (41) is disposed between the second gripping arm (14) and the third gripping arm (15), the second gripping arm (14) and the third gripping arm (15) being in a gripping position relative to each other; The first gripping arm (13), the second gripping arm (14) and the third gripping arm (15) are arranged to rotate the first workpiece (40) and the second workpiece (41) in particular along the second rotation axis (D ２ ) to pivot about said second axis of rotation (D ２ 28. The method according to claim 24, wherein the first and second actuators are pivoted synchronously relative to each other about a first axis.

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