Method for producing a plug-in winding of an electric machine, and clamping device
Patent Information
- Application Number
- EP2024701685
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2023-02-02
- Filing Date
- 2024-01-23
- Publication Date
- 2025-12-10
AI Technical Summary
The existing methods for producing plug-in windings of electrical machines do not effectively enhance the bracing of rod ends during welding, resulting in a weak cohesive connection and increased porosity in the weld seam.
A method involving a clamping device with a preload force and an embossing force is used to plastically deform the rod ends of conductor bars, ensuring a strong weld by generating a significant embossing force greater than the preload force, followed by a controlled operating clamping force during the welding process, which can be adjusted based on real-time feedback from sensors and cameras to maintain optimal alignment and contact.
This approach results in a robust weld seam with reduced porosity and misalignment, enhancing the quality and reliability of the weld while minimizing process costs and scrap rates.
Smart Images
Figure EP2024051557_08082024_PF_FP
Abstract
Description
[0001] Description
[0002] Method for producing a plug-in winding of an electrical machine and clamping device
[0003] The present invention relates to a method for producing a plug-in winding of an electrical machine, wherein pairs of conductor bars to be welded at bar ends are plastically deformed by a generated stamping force. The invention also relates to a clamping device configured to carry out the inventive method.
[0004] State of the art
[0005] US 2022 / 0247285 A1 discloses a manufacturing method for the plug-in winding of a stator of an electrical machine and a clamping tool.
[0006] The object of the present invention is to improve the clamping of bar ends of conductor bars of a plug-in winding of an electrical machine during welding of the bar ends, thereby increasing the material connection after welding of the bar ends.
[0007] Disclosure of the invention
[0008] The above object is achieved according to the invention according to independent claims 1 and 6.
[0009] The present invention relates to a method for producing a plug-in winding of an electrical machine, comprising providing a stator of the electrical machine. The provided stator has a plurality of conductor bars of the plug-in winding, which are each received in particular in a hollow space running parallel to the axial direction, preferably a slot, or, advantageously in the case of U-shaped bent conductor bars, in two different hollow spaces running parallel to the axial direction, preferably slots, of the stator. The hollow space or hollow spaces can optionally be at least partially closed in the radial direction or tensioning direction. The conductor bars are preferably received in the slots before the method by plugging them in. An insulating paper is advantageously arranged between the conductor bars and the iron core of the stator.Two or one pair of bar ends of different conductor bars are interlaced with one another, in particular according to a predetermined winding pattern, and in particular outside the stator, preferably at the winding overhang. In other words, the stator has pairs of bar ends of different conductor bars to be welded, wherein the bar ends are interlaced with one another outside the stator core at one end face of the stator. In other words, the provided stator therefore has interlaced conductor bars, wherein the interlacing was advantageously carried out before the method. Subsequently, according to the invention, the provided stator is arranged in or on a clamping device, wherein the clamping device comprises at least a first clamping jaw, a second clamping jaw and a spacer element.When arranging the stator on the clamping device, the first and second clamping jaws are advantageously arranged in a radial direction or clamping direction of the stator, so that they are preferably designed to clamp the pairs to be welded at bar ends of the interlaced conductor bars. Advantageously, the clamping device comprises as many first and second clamping jaws as there are grooves or cavities in the stator in which the conductor bars are received. The spacer element is arranged between the first and second clamping jaws. By arranging or inserting the provided stator into the clamping device, the spacer element is positioned from above, below or laterally between two pairs of bar ends to be welded.In one step of the method, the first clamping jaw is positioned at a predetermined stop position by moving the first clamping jaw from the inside outward in the radial direction. Subsequently, a preload force is generated in the radial direction from the outside inward on the second clamping jaw and toward the first clamping jaw, whereby the pairs of bar ends to be welded are clamped with the spacer element between the second clamping jaw and the first clamping jaw. The preload force can be generated, for example, by arranging a spring element on the second clamping jaw.Preferably, all of the bar ends of the interlaced conductor bars to be welded are clamped simultaneously between the first and second clamping jaws of the clamping device by means of the generated pre-tensioning force by means of a separate spring element, wherein the plurality of spring elements of the clamping device are positioned or arranged on the second clamping jaws by means of an actuator, wherein the actuator is designed to displace the spring elements in a respective radial clamping direction by means of a rotatably mounted guide rail, wherein the guide rail has, for example, a groove for each spring element, into which groove a guide element for the spring engages with a pin and the guide element for the spring can be displaced by the rotation of the guide rail. The at least one spacer element holds the pairs of bar ends to be welded, in particular at a respective predetermined distance.Subsequently, according to the invention, an embossing force is generated from the outside to the inside in the radial clamping direction for a predetermined period of time. The embossing force is preferably generated by means of an actuator which is in at least indirect contact with the second clamping jaw and is designed to generate the embossing force on the second clamping jaw. The actuator is, for example, a hydraulic, pneumatic or electric actuator. The generated embossing force acts in particular on the second clamping jaw in the direction of the first clamping jaw and thus advantageously also on all pairs of bar ends to be welded that are clamped between the second clamping jaw and the first clamping jaw with the spacer element. The embossing force is greater than the pre-tensioning force, in particular by at least a factor of ten or by an order of magnitude. The generated embossing force advantageously plastically deforms the conductor bars of the pairs of clamped bar ends.Preferably, all bar ends of the interlaced conductor bars to be welded are clamped simultaneously between the first and second clamping jaws of the clamping device by the preload force generated by a spring, and subsequently, all clamped bar ends to be welded are simultaneously plastically deformed by the compression force generated by an actuator. A welding process is then carried out to weld the bar ends of each clamped pair of bar ends, in particular a laser welding process. Alternative welding processes, such as resistance welding or arc welding, or combinations of welding processes are possible. The welding process is preferably repeated for all or each pair of clamped bar ends to be welded.In an alternative embodiment of the invention, the welding process is carried out on all clamped bar ends simultaneously. By means of the method according to the invention, a zero gap is achieved between the bar ends to be welded during the welding process, even in the case of incorrect positioning of the conductor bars when the stator is prepared, which results in an increased quality of the material-to-material connection or of the weld seam between the welded bar ends of the conductor bars. In addition, the number of pores in the weld seam is advantageously reduced. The fact that the clamping and embossing is carried out with a clamping device also results in low process costs.
[0010] In a preferred development of the method, an operating clamping force acts before or during the welding process in the radial clamping direction from outside to inside, in particular on the second clamping jaw in the direction of the first clamping jaw. In other words, an operating clamping force is advantageously generated after the generation of the embossing force, which acts during the welding process on the bar ends clamped between the first and second clamping jaws and to be welded. The operating clamping force is smaller than the embossing force. Preferably, the operating clamping force is smaller than or equal to the preload force. The operating clamping force therefore advantageously corresponds to the preload force and is generated in particular by means of the spring element. Alternatively, the operating clamping force is particularly preferably smaller than the preload force.The operating clamping force can be generated in particular by a second position of the spring element or the link or by means of the actuator for generating the embossing force. In other words, the actuator is advantageously deactivated after the embossing force has been generated or controlled to generate a lower operating clamping force. The operating clamping force is preferably designed to bring the surfaces of the rod ends to be welded into contact. The contact is advantageously detected in a further step by electrically detecting a resistance between the rod ends to be welded or by visual detection using a camera. This further step sets a low force between the rod ends to be welded during the welding process, thereby increasing the quality of the weld seam.
[0011] For example, the number of pores in the weld seam is further reduced. This extension also results in a more robust laser welding process with less spatter.
[0012] In a further development of the invention, at least one pair of the bar ends to be welded is captured as a camera image using a camera, wherein the prestressing force and / or the stamping force and / or the operating clamping force and / or the welding process are adjusted depending on the captured camera image, for example the laser power and / or the feed rate of the laser beam are adjusted during the welding process. The camera image can be used, for example, to evaluate the quality of the plastic deformation and / or the alignment of the bar ends to one another, wherein in particular the stamping force is increased to set a predetermined quality or alignment of the bar ends of the conductor bars to one another if the assessed quality lies below a threshold value or if an error, such as a larger gap between the clamped pair of bar ends and the pair to be welded, is detected by image analysis methods.This continuation allows for the detection of minor misalignments of the conductor bars and / or minor misalignments of the interlaced bar ends and reduces rejects.
[0013] In a further embodiment of the invention, the preload force and / or the stamping force and / or the operating clamping force are detected and in particular controlled by means of a force sensor. The welding process is then advantageously adapted depending on the detected preload force and / or the detected stamping force and / or the detected operating clamping force, for example the laser power and / or the feed rate of the laser beam. In this embodiment, a very low operating clamping force can be generated and / or the welding process, for example welding parameters, can be adapted to the detected operating clamping force, thereby increasing the quality of the weld seam. Alternatively, in this embodiment, a very high stamping force can be generated based on a detected camera image for plastic deformation of the rod ends without the risk of damaging the rod ends, thereby increasing the quality of the weld seam.
[0014] In another embodiment of the invention, an electrical variable between the rod ends to be welded is detected to generate the embossing force, wherein the electrical variable is, in particular, the magnitude of an electrical current and / or an electrical resistance and / or an electrical impedance between the rod ends to be welded. Subsequently, the magnitude of the operating clamping force and / or the welding process are adjusted depending on the detected electrical variable. This embodiment allows contact between the rod ends to be electrically detected, minimizing the operating clamping force and / or optimizing the welding process.The invention also relates to a clamping device which is designed to be arranged on a head side of the stator of an electrical machine, said head side being perpendicular to the axial direction, wherein the stator has conductor bars of a plug-in winding which protrude from the stator at the head side and are interlaced with one another in pairs according to a predetermined winding pattern. The clamping device comprises at least one first clamping jaw which is designed to be displaced in a radial clamping direction perpendicular to the axial direction of the stator from the inside to the outside in the direction of the bar end which is furthest inside in the radial clamping direction and to be positioned at a predetermined stop position.The clamping device also has a second clamping jaw, which is designed to be displaced in the radial clamping direction from the outside to the inside toward the first clamping jaw toward the outermost rod end in the radial clamping direction. Pairs of rod ends to be welded are clamped together with at least one spacer element between the second clamping jaw and the first clamping jaw by generating a preload force. The at least one spacer element of the clamping device, which is movably mounted in the radial clamping direction, maintains the pairs of rod ends to be welded at a predetermined distance from one another.The clamping device further comprises a spring element or an actuator, which is configured to generate a preload force and / or an operating clamping force in the radial clamping direction on the second clamping jaw for clamping the pairs of bar ends to be welded with at least one spacer element between the second clamping jaw and the first clamping jaw. Furthermore, the clamping device comprises at least one actuator, which is configured to generate an embossing force in the radial clamping direction for clamping, in particular on the second clamping jaw. The optional actuator for generating the preload force and the actuator for generating the embossing force can be the same actuator or different or separate actuators.
[0015] Preferably, the at least one spacer element of the clamping device is movably mounted on the first and / or second clamping jaw in the radial clamping direction, wherein the at least one spacer element is connected to the first and / or second clamping pack by means of a spring and is designed to be inserted between two pairs of rod ends to be welded when the stator is arranged in the clamping device, in particular by means of two oblique side surfaces of the spacer element facing the rod ends. Preferably, the second clamping jaw has a first element and a second element, wherein the first element is arranged more inwardly than the second element in the radial clamping direction and is designed to directly contact the rod end arranged at the outermost point in the radial clamping direction.The first element and the second element of the second clamping jaw are advantageously in contact, in particular in releasable contact, at least in the radial clamping direction. Advantageously, the first and second elements are not fixed to one another. In particular, the first and second elements are advantageously designed to engage with one another. Advantageously, the first and second elements are designed to transfer a force acting on the first element of the second clamping jaw from the first element to the second element. The two elements of the second clamping jaw or the two-part design of the second clamping jaw make assembly of the second clamping jaw easier and, above all, make replacement of the wear-prone first element of the second clamping jaw easier.
[0016] In a further embodiment, the clamping device comprises at least one force sensor which is designed to detect the pre-tensioning force applied by means of the actuator and / or an operating clamping force and / or embossing force.
[0017] In another embodiment, it can be provided that the clamping device comprises a camera which is designed to capture at least one pair of the clamped and to-be-welded bar ends as a camera image.
[0018] In a further embodiment, the clamping device comprises a control unit which is configured to control the actuator for adjusting the pre-tensioning force, the operating clamping force and / or the detected embossing force based on the detected pre-tensioning force, the detected operating clamping force and / or the detected embossing force and / or the detected camera image.
[0019] Further advantages will become apparent from the following description of embodiments with reference to the figures.
[0020] Figure 1 : Flowchart of the process as a block diagram
[0021] Figure 2: Clamping device with stator provided in side view Figure 3: Section of a clamping device with stator provided in cross section
[0022] Examples of implementation
[0023] Figure 1 shows a flowchart of the method for producing a plug-in winding of an electrical machine as a schematic block diagram. In a first step 110 of the method, a stator of the electrical machine is provided. The stator has a plurality of conductor bars of the plug-in winding accommodated in slots or cavities. At the winding head of the plug-in winding or at an end face of the stator, two bar ends of different conductor bars to be welded are interlaced. The stator is then arranged 120 in a clamping device.The clamping device preferably comprises a plurality of first clamping jaws, second clamping jaws, and at least one spacer element between the respective first and second clamping jaws per radial clamping direction, wherein the spacer element is arranged between the first and second clamping jaws and between two pairs of interlaced bar ends to be welded. The number of spacer elements depends on the size and winding pattern of the stator's plug-in winding. Subsequently, in a further step 130, the first clamping jaw is positioned at a predetermined stop position in the respective radial clamping direction. Positioning is achieved by moving the first clamping jaw from the inside to the outside in the respective radial clamping direction.The plurality of first clamping jaw ends of the clamping device can be positioned simultaneously at the predetermined stop position in step 130, for example by a cone moving into the clamping device. In step 140, a preload force is then generated in the radial clamping direction on the second clamping jaw to the first clamping jaw, in particular from the outside to the inside. The generated preload force clamps the pairs of bar ends to be welded with the spacer element between the second clamping jaw and the first clamping jaw. The preload force is preferably generated by means of a spring element or an actuator simultaneously for all radial clamping directions, wherein the actuator advantageously positions one spring element on the second clamping jaw for each radial clamping direction. The positioning of the plurality of respective spring elements on the respective second clamping jaw by the actuator can be achieved, for example, by means of a rotary link.It can be provided that during the generation 140 of the prestressing force in an optional step 141, at least one pair of the bar ends to be welded is captured as a camera image by means of a camera. In addition, it can optionally be provided to carry out a detection 142 of the generated prestressing force using a force sensor. Subsequently, in step 140, the generated prestressing force is optionally adjusted depending on the captured camera image and / or the detected prestressing force. Thereafter, in step 150, a stamping force is generated in the radial clamping direction on the second clamping jaw to the first clamping jaw for a predetermined period of time. The generated stamping force is greater than the prestressing force, wherein the conductor bars of the pairs of clamped bar ends are plastically deformed by the generated stamping force.As a result, gap dimensions and / or stresses in the material of the conductor bars present prior to plastic deformation are reduced, thereby increasing the quality and / or the stresses in the weld seam subsequently created between the interlaced bar ends of the conductor bars. It can be provided that during step 150, in optional step 151, at least one pair of the bar ends to be welded is captured by a camera as a camera image. In addition, it can optionally be provided to carry out a detection 152 of the generated stamping force using a force sensor. Subsequently, optionally in step 150, the magnitude of the stamping force is adjusted depending on the captured camera image and / or the captured stamping force. Subsequently, in step 160, in particular, an operating clamping force is generated (step 160a), and subsequently a welding process for welding the bar ends of a respective pair of the bar ends to be welded is carried out (step 160b).During the execution 160b, 160 of the welding process or welding, the generated or applied or acting operating clamping force acts in the radial clamping direction, in particular on the second clamping jaw from the outside inwards to the first clamping jaw, wherein the operating clamping force is smaller than the stamping force. Preferably, the generated operating clamping force is in particular smaller than or equal to the pre-tensioning force. Furthermore, it can be provided that before or during the execution 160 of the welding process in the optional step 161, at least one pair of the bar ends to be welded is captured as a camera image by means of a camera. It can further be provided that before or during the execution 160 of the welding process, the generated operating clamping force is captured by means of a force sensor in the optional step 162.Furthermore, it can be provided that electrical contact between the surfaces of the rod ends to be welded is detected by optionally detecting 163 an electrical variable, in particular the electrical resistance, between the rod ends to be welded. Subsequently, in step 160, the magnitude of the generated operating clamping force is optionally adjusted as a function of the detected camera image and / or the detected operating clamping force and / or as a function of the detected electrical variable, wherein the adjustment of the operating clamping force takes place in particular before the welding process is carried out. It can also optionally be provided that the welding process is adjusted as a function of the detected camera image and / or the detected operating clamping force and / or as a function of the detected electrical variable.
[0024] Figure 2 shows a schematic side view of a clamping device 200 with a stator 250 provided. For clarity of illustration, the stator 250 in Figure 2 has only one pair of interlaced bar ends 270 of conductor bars 270 of the plug-in winding of the stator on the end face 251 perpendicular to the axial direction 290 of the stator 250. The conductor bars are received in slots 252 running parallel to the axial direction 290. Thus, a plurality of further interlaced bar ends 270 of conductor bars are not shown in Figure 2. The clamping device 200 is arranged on the end face 251 of the provided stator 250. The clamping device can comprise a laser source 210 and / or a camera 220. Alternatively, the laser source 210 and / or the camera 220 can be arranged outside the clamping device 200.The laser source 210 is configured to weld the interlaced bar ends 270 of the plurality of conductor bars 260, thereby creating the plug-in winding of the stator 250. The plurality of pairs of welded bar ends 270 on an end face 251 of the stator 250 is also referred to as the winding head.
[0025] Figure 3 shows a schematic cross-sectional view of a section of the clamping device 200 with the provided stator 250. The clamping device 200 is designed to be arranged on the end face 251 of the stator 250 of an electrical machine, said end face being perpendicular to the axial direction 290. The clamping device
[0026] 200 comprises a first clamping jaw 201, which is configured to be displaced in a radial clamping direction 295 perpendicular to the axial direction 290 of the stator 250 from a starting position x1 from the inside to the outside in the direction of the innermost rod end 270, 270a in the radial clamping direction 295 and positioned at a predetermined stop position x2. The clamping device further comprises a second clamping jaw 202, which is configured to be displaced in the radial clamping direction 295 from the outside to the inside in the direction of the first clamping jaw
[0027] 201 can be displaced against the outermost rod end 270, 270f in the radial clamping direction 295 and to generate a preload force acting in the radial clamping direction 295 against the outermost rod end 270, 270f. The second clamping jaw 202 can be designed in one piece or, advantageously, in two pieces. If the second clamping jaw 202 comprises a first element 202a and a second element 202b of the second clamping jaw, the assembly of the first element 202a and the replacement of the first element 202a when the first element 202a of the second clamping jaw 202 becomes worn are simplified. The first element 202a is subject to increased wear, for example due to stamping and proximity to the welding process. The second element 202b can remain unchanged when the first element 202a is replaced.In the exemplary embodiment of Figure 3, three pairs 280 of the bar ends 270 to be welded are clamped together with two spacer elements 203 between the second clamping jaw 202 and the first clamping jaw 201 positioned at the stop position x2 by the preload force generated by the spring element 205. In the example of Figure 3, the second clamping jaw 202 is displaced and the preload force is generated by the spring element 205, which is received and guided in a guide element 206. The guide element 206 can be displaced in the radial clamping direction 295 by rotating a rotatable guide 204, which has guide grooves 204a for this purpose. The rotation of the guide 204 is preferably carried out by means of an actuator (not shown here).Furthermore, the two spacer elements 203 are movably mounted in the radial clamping direction 295, in particular on the first and / or second clamping jaw 201, 202 and by means of the springs 203a. During clamping, the spacer elements 203 hold the pairs 280 on the bar ends 270 to be welded at a predetermined distance from one another. Figure 3 also shows an actuator 207, which is designed here to generate an operating clamping force and / or a stamping force on the second clamping jaw in the radial clamping direction 295. The stamping force generated by the actuator 207 is detected by a force sensor 208. The force sensor can also be arranged at a different location than in Figure 3; for example, the actuator 207 comprises the force sensor.
Claims
Claims 1 . Method for producing a plug-in winding of an electrical machine, comprising the following steps • Providing (110) a stator (250) of the electrical machine with an axial direction (290), wherein the stator (250) has a plurality of conductor bars (260), wherein two bar ends (270) of different conductor bars (260) to be welded to produce the plug-in winding from the conductor bars (260) are interlaced with one another, • Arrangement (120) of the stator in a clamping device (200), wherein the clamping device (200) comprises at least one first clamping jaw (201), a second clamping jaw (202) and at least one spacer element (203) in a radial clamping direction (295) perpendicular to the axial direction (290), wherein the spacer element (203) is arranged between the first clamping jaw (201) and the second clamping jaw (202) and between two pairs (280) of bar ends (270) to be welded, • Positioning (130) of the first clamping jaw (201) at a predetermined stop position (x2) by moving the first clamping jaw (201) from the inside to the outside in the radial clamping direction (295), • Generation (140) of a pre-tensioning force in the radial clamping direction (295) from the outside to the inside on the second clamping jaw (202) to the first clamping jaw (201), wherein the pairs (280) of the rod ends (270) to be welded are clamped with the spacer element (203) between the second clamping jaw (202) and the first clamping jaw (201), • generating (150) an embossing force in the radial clamping direction (295) on the second clamping jaw (202) to the first clamping jaw (201) for a predetermined period of time, wherein the embossing force is greater than the pre-tensioning force, wherein the conductor bars (260) of the pairs (280) of the clamped bar ends (270) are plastically deformed, and • Carrying out (160) a welding process for welding the rod ends (270) of a respective pair (280) of the rod ends (270) to be welded.
2. The method according to claim 1, wherein during the execution (160) of the welding process an operating clamping force acts in the radial clamping direction (295), wherein the generated operating clamping force is smaller than the embossing force and in particular smaller than or equal to the pre-tensioning force.
3. Method according to one of the preceding claims, wherein at least one pair (280) of the rod ends (270) to be welded is captured by means of a camera (220) as a camera image, wherein the pre-tensioning force, the embossing force, the operating clamping force and / or the welding process are adapted depending on the captured camera image.
4. Method according to one of the preceding claims, wherein the generated pre-tensioning force, the generated embossing force and / or the generated operating clamping force are detected by means of a force sensor, wherein the welding process is adapted as a function of the detected pre-tensioning force, the detected embossing force and / or the detected operating clamping force.
5. Method according to one of the preceding claims, wherein after the generation (150) of the embossing force, a detection (163) of an electrical variable, in particular an electrical resistance, between the rod ends (270) to be welded takes place, wherein the level of the operating clamping force and / or the welding process is adapted depending on the detected electrical variable.
6. Clamping device (200) which is designed to be arranged on an end face (251) of the stator (250) of an electrical machine, said end face (251) being perpendicular to the axial direction (290), wherein the stator (250) has conductor bars (260) which protrude from the stator (250) on the end face (251) and are interlaced in pairs according to a predetermined winding pattern, comprising at least the following components • a first clamping jaw (201) which is designed to be displaced in a radial clamping direction (295) perpendicular to the axial direction (290) of the stator (250) from the inside to the outside in the direction of the rod end (270) which is furthest inside in the radial clamping direction (295) and to be positioned at a predetermined stop position (x2), • a second clamping jaw (202) which is designed to be displaced in the radial clamping direction (295) from the outside inwards in the direction of the first clamping jaw (201) against the rod end (270) which is furthest outwards in the radial clamping direction, wherein pairs (280) of the rod ends (270) to be welded are clamped with at least one spacer element (203) between the second clamping jaw (202) and the first clamping jaw (201), wherein the at least one in the radial clamping direction (295) movably mounted spacer element (203) of the clamping device (200) holds the pairs (280) of bar ends (270) to be welded at a predetermined distance from each other, and • at least one spring element (205) or an actuator which is designed to generate a pre-tensioning force and / or an operating clamping force in the radial clamping direction on the second clamping jaw (202) for clamping the pairs (280) of the bar ends (270) to be welded with at least one spacer element (203) between the second clamping jaw (202) and the first clamping jaw (201), • at least one actuator (207) which is designed to generate an embossing force in the radial clamping direction (295) for clamping, in particular on the second clamping jaw (202).
7. Clamping device according to claim 6, wherein the at least one spacer element (203) is movably mounted on the first clamping jaw (201) and / or the second clamping jaw (202) in the radial clamping direction (295), wherein the at least one spacer element (203) is connected to the first clamping jaw (201) and / or the second clamping jaw (202) by means of a spring and is designed to be inserted between two pairs (280) of rod ends (270) to be welded when the stator (250) is arranged in the clamping device (200) by means of, in particular, two oblique side surfaces of the spacer element (203) pointing towards the rod ends (270).
8. Clamping device according to one of claims 6 or 7, wherein the second clamping jaw (202) comprises a first element (202a) and a second element (202b), wherein the first element (202a) is located more inwardly than the second element (202b) in the radial clamping direction and is designed to directly contact the rod end (270) arranged at the outermost point in the radial clamping direction.
9. Clamping device according to one of claims 6 to 8, comprising the following component • a force sensor (208) which is designed to detect the pre-tensioning force and / or an operating clamping force and / or embossing force applied by means of the actuator (207).
10. Clamping device according to one of claims 6 to 9, comprising the following component • a camera (220) which is configured to capture as a camera image at least one pair (280) of the clamped and to-be-welded rod ends (270). 11 . Clamping device according to one of claims 6 to 10, comprising the following component • a control device which is configured to control the actuator for adjusting the pre-tensioning force, the operating clamping force and / or the detected stamping force based on the detected pre-tensioning force, the detected operating clamping force and / or the detected stamping force and / or the detected camera image.