Twisting method, twisting jig and twisting device for coil segments

Abstract

On an outer peripheral surface of the inner twisting jig (26) corresponding to the innermost layer, a plurality of first accommodation recesses (38a) that accommodate distal end portions (12d) of slot insertion portions (12a) of the normal coil segments (12) and a plurality of second accommodation recesses (38b) that accommodate long distal end portions (14d) of long slot insertion portions (14b) of the modified coil segments (14) are formed at intervals in the circumferential direction. The first accommodation recesses (38a) are located at positions offset in the circumferential direction with respect to the distal end portions (12d) to be accommodated in a state in which the long distal end portions (14d) of the long slot insertion portions (14b) before twisting are inserted into the second accommodation recesses (38b). The inner twisting jig (26) is rotated in this state to perform primary twisting, and then the distal end portions (12d) of the normal coil segments (12) are further inserted into the first accommodation recesses (38a) to perform secondary twisting, the amount of rotation of which is greater than that of the primary twisting.

Description

Technical Field

[0001] The present invention relates to a method for torsion of the coil segment of a rotating electric machine such as an electric motor or a generator, and torsion fixtures and torsion devices used in the torsion process of the coil segment. Background Technology

[0002] As coils in the stator of rotating electrical machines such as motors or generators, a so-called segmented coil is known. This segmented coil is obtained by inserting multiple U-shaped coil segments, each having a pair of slots extending in a straight line, into multiple slots arranged circumferentially along the stator core (iron core) (hereinafter simply referred to as the core), so as to form multiple layers across the slots in the radial direction of the core; for each layer, the distal ends of these coil segments protruding from the end face of the core in the insertion direction are twisted in opposite directions; and the distal ends in adjacent layers are electrically joined in the radial direction of the core by welding or the like. The U-shaped coil segments are also called hairpins.

[0003] Torsion processing includes the concepts of twisting (bending) and folding (folding), and is referred to as torsion below.

[0004] The coil segments mentioned above include coil segments that are to be used as leads (such as input lines and neutral lines), and these coil segments are modified coil segments that protrude a longer length from the end face of the core compared to ordinary coil segments whose distal ends are to be joined together.

[0005] In traditional torsion techniques, when torsion is performed, the distal end of a regular coil segment and the distal end of a variant coil segment located in the same layer as the regular coil segment are inserted into the same torsion fixture. By rotating the torsion fixture, each layer is torsioned circumferentially in the same direction, and the coil segments of adjacent layers in the radial direction are torsioned circumferentially in opposite directions.

[0006] Therefore, after twisting, the distal end of the modified coil segment and the distal end of the ordinary coil segment are in the same position in the circumferential direction. That is, the joints of the distal ends of the ordinary coil segment and the distal ends of the modified coil segment are aligned radially in the core.

[0007] According to this conventional technique, for example, when a lead formed by a modified coil segment in the innermost layer of the core is to be electrically connected to a terminal member arranged radially outward, the connection must be configured to span over the joint row above the distal end of the ordinary coil segment.

[0008] Although the coil described in Patent Document 1 is not constructed to insert a U-shaped coil, as shown in Figure 17(B), the above method is suitable for reducing the size by bending the end of the coil radially along the core.

[0009] [List of Citations]

[0010] [Patent Literature]

[0011] [Patent Document 1] Japanese Patent Application Publication No. 2009-11116 Summary of the Invention

[0012] Technical issues

[0013] In the aforementioned connection structure where the lead wire crosses above the joint row, the modified coil segment should have a long lead wire portion, which leads to an increase in the material cost of the coil segment made of copper, aluminum, etc.

[0014] Furthermore, in this type of stator, the small amount of the coil protruding from the core end face of the coil contributes to the miniaturization of motors, etc., and there are even millimeter-level differences in the effect. Therefore, the above-mentioned connection structure hinders miniaturization.

[0015] Furthermore, when the lead rises to a greater height, the natural frequency of the lead section decreases due to the reduced rigidity of the connection between the lead and the terminal component. Therefore, for example, there is a problem where resonance caused by vibrations associated with the rotation of the vehicle engine could lead to wire breakage stress in the wiring section.

[0016] The present invention was developed in view of this situation, and the object of the present invention is to reduce the cost of the connection between the coil segment and the terminal member in the stator of a rotary electric machine using coil segments and to increase the rigidity of the connection, thereby contributing to the miniaturization of the rotary electric machine.

[0017] [Problem Solution]

[0018] To achieve the above objectives, the method for twisting coil segments according to the present invention includes first preparing a workpiece in which a plurality of coil segments are inserted into a plurality of slots arranged circumferentially along a core configured to form a stator of a rotary motor. The distal ends of each coil segment protruding from the end face of the core toward the insertion direction form a plurality of layers in the radial direction of the core. A short distal end and a long distal end are arranged in one of the plurality of layers. The short distal end is any distal end among the distal ends to be joined with the distal ends of other coil segments, and the long distal end protrudes from the end face of the core and is longer than the short distal end.

[0019] Then, the following steps are performed respectively: with the long end at least partially inserted into the second receiving recess of the torsion clamp and the short end not inserted into the first receiving recess of the torsion clamp, a primary twist is performed, causing the torsion clamp to rotate by a predetermined amount. The torsion clamp includes a first receiving recess configured to receive the short end and a second receiving recess configured to receive the long end. Then, with the long end still at least partially inserted into the second receiving recess and the short end at least partially inserted into the first receiving recess, a secondary twist is performed, causing the torsion clamp to rotate by a greater than predetermined amount.

[0020] In the coil segment torsion method of the present invention, the distal ends of multiple coil segments are torsioned by a first torsion and a second torsion, such that when viewed circumferentially, the long distal ends are arranged between adjacent short distal ends.

[0021] In the above method of twisting the coil segment, it is preferable that, before performing a twist, each of the first receiving recesses is positioned circumferentially offset relative to each short distal end to be received by the first receiving recess, with the long distal end at least partially inserted into the second receiving recess of the twisting fixture, and after performing a twist, each of the first receiving recesses is positioned substantially opposite to each short distal end to be received by the first receiving recess.

[0022] Furthermore, it is preferable that the layer with the long end is the innermost or outermost layer in the radial direction.

[0023] Furthermore, it is preferable that the predetermined amount of rotation of the torsion fixture in the first torsion is about 1 / 2 times the slot spacing, and the amount of rotation of the torsion fixture in the second torsion is more than one time the slot spacing.

[0024] Furthermore, it is preferable to perform a secondary torsion so that the torsion clamp rotates in the opposite direction to the primary torsion.

[0025] Furthermore, in addition to being an implementation of the above-described method, the present invention can also be implemented as a torsion clamp or torsion device suitable for implementing the above-described torsion method. It is not excluded that the present invention can be implemented as an operating method for a torsion device, a computer program for controlling a torsion device, and a computer-readable recording medium storing such a program.

[0026] [Invention Effects]

[0027] According to the above structure, in the stator of a rotary motor using coil segments, the cost of the connection between the coil segments and the terminal components can be reduced, the rigidity of the connection can be increased, and this can help to miniaturize the rotary motor. Attached Figure Description

[0028] Figure 1 This is a perspective view showing an example of the stator of a rotary electric machine manufactured using a torsion method of coil segments according to the invention.

[0029] Figure 2A This is a schematic perspective view showing an example of a typical coil segment.

[0030] Figure 2B This is a schematic perspective view showing an example of a modified coil segment.

[0031] Figure 2C This is a schematic perspective view showing an example of a coil segment with the distal end as the neutral point.

[0032] Figure 3 yes Figure 1 An enlarged perspective view of the main part.

[0033] Figure 4 It is along Figure 1 A schematic cross-sectional view taken from line IV-IV.

[0034] Figure 5 This is a schematic structural diagram of a torsion device as an embodiment of the present invention.

[0035] Figure 6 yes Figure 5 Exploded perspective view of the torsion clamp in the torsion device.

[0036] Figure 7 It is along Figure 6 A schematic cross-sectional view of the internal torsion clamp 26 taken from line VII-VII.

[0037] Figure 8A This is an explanation Figure 5 The diagram showing the torsion operation of the torsion device illustrates the positional relationship between the coil segment before torsion and the receiving recess of the inner torsion clamp in a linear unfolded view.

[0038] Figure 8B Is with Figure 8A The corresponding diagram shows the relationship with Figure 8A The positional relationship between the coil segment before twisting and the receiving recess of the inner twisting fixture at different locations.

[0039] Figure 8C Is with Figure 8A The corresponding figure shows the positional relationship between the coil segment and the inner torsion fixture at the start of the torsion.

[0040] Figure 8D It shows from Figure 8C The diagram shows the state in which the distal end of the modified coil segment is partially inserted into the second receiving recess.

[0041] Figure 8E It shows from Figure 8D The diagram shows the state in which a torsion is performed by rotating the internal torsion fixture.

[0042] Figure 8F It shows from Figure 8E The diagram shows the state in which the distal end of the ordinary coil segment is inserted into the first receiving recess.

[0043] Figure 8G It shows from Figure 8F The diagram shows the state in which the second twist is performed under the given state.

[0044] Figure 9 This is a perspective view of the main parts of the core and coil section, showing the input lead at the end of the secondary twist.

[0045] Figure 10A This is a schematic diagram illustrating the steps of bending the input lead after a second twist, showing the state of the input lead at the end of the second twist.

[0046] Figure 10B It is shown in Figure 10A The diagram shows the state after the bending phase.

[0047] Figure 11A Is with Figure 8A The corresponding figure shows the positional relationship between the coil segment before twisting and the receiving recess of the inner twisting fixture according to the variant example of the twisting fixture.

[0048] Figure 11B Is with Figure 8D The corresponding diagram illustrates the torsion operation in the variant example. Detailed Implementation

[0049] The embodiments of the present invention will now be described with reference to the accompanying drawings.

[0050] First, refer to Figure 1 A schematic construction of an example of a stator of a rotary electric machine that can be manufactured using a torsion method of coil segments according to the invention will be described.

[0051] Figure 1 This is a perspective view of the stator.

[0052] Figure 1The stator 2 shown includes: a hollow cylindrical core 6 having a plurality of slots 4 arranged circumferentially; and three-phase (U-phase, V-phase, W-phase) coils 8, which are constructed by inserting a plurality of U-shaped coil segments (segment conductors) into the slots 4 to span the slots 4 and connect the coil segments. Reference numeral 5 indicates an insulating sheet that insulates the coil segments from the core 6. In the following description, reference numerals including "U" indicate the construction associated with the U-phase coil. The same applies to "V" and "W".

[0053] Each coil segment is inserted into the slot 4 from the lower side of the core 6 along the axial direction, and the portion protruding from the end face on the upper side (input side or power supply side) of the core 6 in the axial direction is bent circumferentially along the core 6 by a torsion jig described later. Bending (torsion) is performed in opposite directions on each radially adjacent layer of the core 6, and after torsion, the distal ends of the coil segments facing each other between radially adjacent layers are electrically joined together.

[0054] although Figure 1 The state before joining is shown, but in the following description, the structure of the distal ends facing each other (more precisely, the structure of the portions of the coil segment where the insulating film is removed at their distal ends facing each other) is referred to as the joint 10.

[0055] In stator 2, six slot inserts (described later) of coil segments are inserted into each slot 4. Since all coil segments have the same thickness, the radial arrangement of the six slot inserts inserted into a slot 4 is the same for all slots. Therefore, the six slot inserts inserted into a slot can be considered to form six layers stacked from the outermost circumference to the innermost circumference, and in this specification, unless otherwise stated, the term "layer" refers to a layer of the slot inserts.

[0056] The core 6 has a structure in which multiple thin annular electromagnetic steel plates, formed by stamping or etching, are stacked axially and integrally integrated with each other. Multiple teeth 7 (pole teeth) protruding toward the center of the core 6 are radially formed at predetermined circumferential intervals on the inner circumferential side of the core 6. The inner circumferential surface of the core 6 is essentially formed by the distal surfaces of each tooth 7, but the distal surfaces of each tooth 7 are separated from each other. (For easy viewing...) Figure 1 The reference numerals near the center of the figure are partially filled in white, but within the filled portion, the individual teeth 7 are also separated from each other. Furthermore, grooves 4 are formed between adjacent teeth 7.

[0057] The rotor (not shown) to be inserted into the stator 2 of this embodiment has eight poles (magnetic poles), and relative to the eight poles, each phase of the three-phase coil 8 has two slots. Therefore, a total of forty-eight slots 4 are arranged in the core 6.

[0058] Here, Figure 2A An exemplary coil segment is shown.

[0059] Each coil segment is formed by bending and deforming a rectangular wire covered with an insulating film into a U-shape. Specifically, as shown... Figure 2A As shown, the coil segment 12 has a pair of slot insertion portions 12a and 12b extending in a straight line, and a connecting portion 12c connecting the pair of slot insertion portions 12a and 12b. The connecting portion 12c has a stepped shape so that one slot insertion portion 12a and the other slot insertion portion 12b can be arranged in different layers.

[0060] Reference numeral 12d shows the extent that the coil segment 12 protrudes from the end face of the core 6 when it is inserted into the core 6.

[0061] Furthermore, at a predetermined length on the distal side of each slot insertion portion 12a, 12b along the insertion direction (within a range narrower than that indicated by reference numeral 12d), the insulating film is removed, and this portion can be electrically connected to slot insertion portions, connecting terminals, etc. of other coil segments.

[0062] The coil segment in this embodiment includes: a standard coil segment 12, which has slot insertion portions 12a and 12b with lengths equal to... Figure 2A The lengths shown are the same, such as Figure 1 As shown, the distal end of the ordinary coil segment 12 is connected to other coil segments at the joint 10; and, in addition, it includes a modified coil segment 14, which has a slot insertion portion protruding from the end face of the core 6 for a longer length than the slot insertion portion of the coil segment 12 protruding from the end face of the core 6; and a coil segment 16, which similarly has a slot insertion portion protruding from the end face of the core 6 for a longer length than the slot insertion portion of the coil segment 12 protruding from the end face of the core 6, and forms a neutral line.

[0063] Figure 2B An exemplary variant coil segment 14 is shown. The variant coil segment 14 and the coil segment 12 are similar in that the variant coil segment 14 has a pair of slot insertion portions 14a and 14b that extend in a straight line respectively, and a connecting portion 14c connecting the pair of slot insertion portions 14a and 14b, and the connecting portion 14c has a stepped shape (crank shape) for layer replacement.

[0064] However, one slot insertion portion 14b of the modified coil segment 14 is longer than the other slot insertion portion 14a, the length of which is similar to the length of the slot insertion portions 12a and 12b of the ordinary coil segment 12. The distal end of the slot insertion portion 14b protruding from the end face of the core 6 is longer than the distal ends of the slot insertion portions 12a, 12b, and 14a protruding from the end face of the core 6, and this distal end of the slot insertion portion 14b becomes the input lead. Reference numeral 14d shows the long distal end defined as the range of the slot insertion portion 14b protruding from the end face of the core 6 when the coil segment 14 is inserted into the core 6. On the slot insertion portion 14a side, the protrusion is... Figure 2A The portion of the same length as 12d.

[0065] In the following text, the portion indicated by reference numeral 14d is referred to as the long distal end, and the portion indicated by reference numeral 12d is referred to as the short distal end.

[0066] In addition, Figure 2C In the example, coil segment 16 has a distal end that will become the neutral line.

[0067] In addition, in coil segment 16, one slot insertion portion 16b is slightly longer than the other slot insertion portion 16a.

[0068] Strictly speaking, in the same ordinary coil segment 12, the length of each slot insertion protruding from the end face of the core 6 varies slightly from one another depending on the layer formed by the slot insertion. Correspondingly, the circumferential length between the slots 4 varies depending on the radial position of the core 6.

[0069] However, because the length difference between the slot insertion portions of coil segments 12 and 16 is less than Figure 2B Therefore, when the slot insertion portion 14b is longer than the other portions, only the long end 14d of the slot insertion portion 14b of the coil segment 14 is considered to be the object of the first twist, which will be described later.

[0070] Back Figure 1 As described above, six slot inserts are inserted into each slot 4, such that the inserted slot inserts are arranged in a row radially along the core 6. Each phase coil is constructed such that multiple coil segments are connected in series by electrically connecting the slot inserts facing each other at the junction 10, thereby forming two coils each having approximately six turns around the core 6 and arranged at different circumferential positions, and these two coils are also connected in parallel. Each coil is wired from the innermost layer to the outermost layer and then back to the innermost layer, with both ends of the coil located in the innermost layer.

[0071] like Figure 1As shown, in the innermost layer of core 6, input leads 14U1, 14U2, 14V1, 14V2, 14W1, and 14W2 are arranged, formed by bending the long distal end 14d of the modified coil segment 14. For example, each of the distal ends of these leads is electrically connected to some of the terminal members 15U, 15V, and 15W connected to the AC output section of the inverter. Figure 1 The reference numerals in the figures indicate that the input leads 14U1 to 14W2 are located at one end of each coil, and, for example, terminal member 15U is also used to connect the two coils of phase U in parallel. The same applies to phases V and W.

[0072] Furthermore, in the innermost layer, neutral lines 16U1, 16U2, 16V1, 16V2, 16W1, and 16W2, formed respectively from the distal ends of the longer slot insertion portions of coil segments 16, are arranged. These neutral lines are electrically connected to a long plate-shaped common conductor (not shown) that serves as the neutral point. Neutral lines 16U1 to 16W2 are located at the other end of each coil.

[0073] Figure 3 yes Figure 1 Enlarged view of the main parts.

[0074] like Figure 3 As shown, the input leads 14U1, 14U2, 14V1, and 14V2 are arranged to lie horizontally in the circumferential direction of the core 6 between the joints 10 of the coil segment 12 that are joined to each other (in the circumferential gap 21 between the rows of joints 10 arranged radially). Figure 3 Input leads 14W1 and 14W2 (not shown) Figure 1 (As shown) is arranged similarly.

[0075] That is, the innermost distal end of the modified coil segment 14 located at one end in the radial direction is arranged in the gap 21 between the joints 10 and leads to the other end (outermost peripheral side) in the radial direction, wherein the length of the distal end of the modified coil segment 14 protruding from the end face of the core 6 is longer than the length of the distal end of the ordinary coil segment 12 that protrudes from the end face of the core 6 at the joint 10.

[0076] More specifically, each of the input leads 14U1, 14U2, 14V1, and 14V2 includes: a bend 14d-1 formed by bending (twisting) the long distal end 14d of the modified coil segment 14 and the short distal end 12d of the ordinary coil segment 12 in the same layer in the same direction; a lead-out portion 14d-2 extending from the inner circumferential side to the outer circumferential side in the gap 21 between the rows of the joint 10; and a riser 14d-3 rising axially along the core 6 from the end of the lead-out portion 14d-2 at a position protruding outward from the outermost layer. Each riser 14d-3 is connected to a terminal member 15U or 15V.

[0077] The outlet section 14d-2 is the part that bends radially at the position corresponding to the gap 21.

[0078] Figure 1 The input leads 14W1 and 14W2 shown also have the same structure.

[0079] Figure 4 It shows along Figure 1 A schematic cross-sectional view taken from line IV-IV.

[0080] like Figure 4 As shown, by employing the terminal connection structure described above, which consists of an input lead and a terminal member, the input lead 14U1 can be connected to the terminal member 15U at a relatively low height (within a short distance) from the end face of the core. This also applies to other input leads.

[0081] Therefore, compared to the conventional structure, the material cost of the coil segment can be reduced. In the conventional structure, the input lead rises at the innermost position and the terminal member crosses over the row of the joint 10 to connect with the input lead. Furthermore, since the height of the lead-out portion 14d-2 of the input lead in the axial direction of the core 6 can be reduced, this greatly contributes to the miniaturization of the stator 2.

[0082] Despite Figure 4 In the configuration, the rising length of the rising section 14d-3 is relatively long. However, even if the rising length is less than this rising length, or even without the rising section 14d-3, the coil can be connected to the terminal member through the terminal connection configuration described herein. Based on these configurations, the material cost reduction of the coil segment and the miniaturization of the stator 2 can be further improved.

[0083] Furthermore, since the height of the lead-out portion 14d-2 of the input lead in the axial direction of the core 6 can be reduced, the rigidity of the connection between the input lead and the terminal member can be increased. This allows for an increase in the natural frequency of the input lead. That is, although the natural frequency of the input lead decreases when the rigidity of the connection is low, this decrease in natural frequency can be suppressed. For example, by increasing the natural frequency in this way, the risk of wire breakage stress on the wiring section due to resonance of the connection due to vibrations associated with the rotation of the vehicle engine can be reduced.

[0084] Next, refer to Figures 5 to 8G This paper will describe a method for twisting a coil segment that can achieve the terminal connection structure with the above-mentioned effects, as well as embodiments of the twisting fixture and the twisting device used in the twisting method.

[0085] Figure 5This is a schematic structural diagram of a torsion device according to an embodiment of the present invention.

[0086] like Figure 5 As shown, the torsion device 18 includes: a workpiece holding mechanism 20 configured to hold the stator 2 (in which appropriate coil segments are inserted into the slots 4 of the core 6) before the torsion process, such that the protruding distal ends of the coil segments face downward; a torsion clamp 22; a rotation drive mechanism 24 configured to rotate and drive the torsion clamp 22; a controller 25 configured to control the rotation drive mechanism 24 and execute the torsion program; and so on.

[0087] The torsion clamp 22 is a tool that bends the distal ends of the slotted insertion portions of coil segments 12, 14, and 16 along the circumference of the core 6 in the insertion direction. Figure 1 Among the multiple slots 4 of the core 6 shown, one protrudes from the end face of the core 6 and is located in the innermost layer and the adjacent layer of the innermost layer (the second layer from the inner circumferential side).

[0088] The torsion clamp 22 includes: an inner torsion clamp 26 configured to torsion the distal end of a slot insertion portion disposed in the innermost layer; and an outer torsion clamp 28 configured to torsion the distal end of a slot insertion portion disposed in a second layer from the inner circumferential side. The inner torsion clamp 26 has a diameter corresponding to the innermost layer in the radial direction, in which the distal end 14d of the slot insertion portion 14b forming the modified coil segment 14 is disposed, and the outer torsion clamp 28 has a diameter corresponding to the second layer from the inner circumferential side.

[0089] The rotary drive mechanism 24 includes a rotary drive mechanism configured to rotary drive the inner torsion clamp 26 and the outer torsion clamp 28, respectively. The rotary drive mechanism drives the inner torsion clamp 26 via power from the electric motor 30 and drives the outer torsion clamp 28 via power from the electric motor 32. The electric motors 30 and 32 are connected to the controller 25 via electric motor drivers. Data such as the amount and direction of rotation of the inner torsion clamp 26 and the outer torsion clamp 28 are stored in the non-volatile memory 25a of the controller 25, and the controller 25 controls the rotary drive mechanism 24 based on this data.

[0090] The workpiece holding mechanism 20 can be moved vertically (arrow Z direction) by the drive mechanism 34, and during the torsion operation, the stator 2 descends and the torsion fixture 22 rotates simultaneously under the control of the controller 25.

[0091] Figure 6 yes Figure 5 Exploded perspective view of the torsion clamp in the torsion device.

[0092] like Figure 6As shown, the internal torsion clamp 26 includes: a hollow cylindrical clamp body 36 connected to a rotary drive mechanism 24; and a first receiving recess 38a, a second receiving recess 38b, and a third receiving recess 38c formed on the outer peripheral surface of the clamp body 36 at its upper axial end. The first receiving recess 38a, the second receiving recess 38b, and the third receiving recess 38c are formed at intervals in the circumferential direction.

[0093] Figure 7 It is along Figure 6 A schematic cross-sectional view of the internal torsion clamp 26 taken from line VII-VII.

[0094] like Figure 7 As shown, an insertion hole 36b is formed on the bottom surface 36a of the fixture body 36, into which the drive shaft of the rotary drive mechanism 24 is inserted. Furthermore, a plurality of threaded holes 36c (four in this case) are formed at equal intervals along the circumferential direction on the bottom surface 36a. The fixture body 36 is fastened to the rotary drive mechanism 24 using bolts through these threaded holes 36c.

[0095] A stepped annular guide surface 36d is formed on the upper end side of the fixture body 36. The stepped annular guide surface 36d is configured to guide the distal end of the slot insertion portion of each coil segment to the respective receiving recess.

[0096] The first receiving recess 38a receives the distal ends (short distal ends 12d) of the paired slot insertion portions of the coil segments 12, 14, and 16, which are formed to be electrically connected to each other to form the joint portion 10.

[0097] The distal ends (long distal ends 14d) of the second receiving recess 38b receiving groove insertion part 14b, which respectively serve as input leads 14U1, 14U2, 14V1, 14V2, 14W1, and 14W2.

[0098] The axial height of the third receiving recess 38c is less than the axial height of the second receiving recess 38b and greater than the axial height of the first receiving recess 38a, and the third receiving recess 38c receives the distal end of the slot insertion portion 16b (see...). Figure 2C (Hereinafter referred to as the distal end 16d), the slot insertion portion 16b is the longer slot insertion portion of the coil segment 16 to become the neutral line.

[0099] Incidentally, the extent of each distal end housed in the first receiving recess 38a is within the slot insertion portion (slot insertion portion 14a for coil segment 14) of each coil segment 12, 14, 16, extending from the end of the slot insertion portion to approximately... Figure 1 The range of the portion that rises axially along the core 6. That is, for example, a portion of the range shown as the short distal end 12d.

[0100] The extent of each distal end 14d housed in the second receiving recess 38b is within the slot insertion portion 14b of each coil segment 14, extending from the end of the slot insertion portion 14b to approximately forming... Figure 3 The extent of the leading portion 14-2 and the rising portion 14-3. This is part of the extent shown as the long end 14d.

[0101] The extent of each distal end 16d housed in the third receiving recess 38c is also consistent with these extents.

[0102] like Figure 6 As shown, the external torsion clamp 28 includes a hollow cylindrical clamp body 40 and a flange 42 integrally formed with the clamp body 40 on the lower surface of the clamp body 40. Receiving recesses 40a are formed circumferentially at intervals on the inner circumferential surface of the upper axial end of the clamp body 40. These receiving recesses 40a are configured to receive the distal end of a slotted insertion portion arranged in a second layer from the inner circumferential side. The height of each receiving recess 40a is similar to the height of the first receiving recess 38a of the inner torsion clamp 26.

[0103] The external torsion clamp 28 is connected to the rotary drive mechanism 24 via a flange 42 and a gear structure such as a worm gear.

[0104] The inner torsion clamp 26 and the outer torsion clamp 28 prevent the slot insertion portion inserted into the receiving recess of the other torsion clamp from falling off through the side surface portion of the inner torsion clamp 26 and the side surface portion of the outer torsion clamp 28, respectively.

[0105] Next, refer to Figures 8A to 8G This document describes the operation of positioning the distal end 14d of the modified coil segment in the gap 21 between the rows of the joint 10 using an inner torsion clamp 26, which serves as a single torsion clamp, and the construction of this operation. The operation described herein is an embodiment of the coil segment torsion method of the present invention.

[0106] Incidentally, in Figures 8A to 8G In the figure, for ease of understanding, a portion of the circumferential arrangement of the distal end of the coil segment and the circumferential arrangement of the receiving recess of the inner torsion clamp 26 corresponding to the distal end of the coil segment are laid out in a straight line to schematically show the positional relationship of these objects. Furthermore, each of the short distal end 12d, long distal end 14d, and distal end 16d in the figure includes a portion with the insulating film peeled off and a portion without the insulating film peeled off.

[0107] like Figure 8AAs shown, in the state before twisting, the short distal end 12d of the ordinary coil segment 12 and the long distal end 14d of the modified coil segment 14, both protruding from the end face of the core 6 of the stator 2, are arranged with the same slot pitch P1 in the circumferential direction (arrow R direction) of the core 6. The slot pitch P1 is the forming spacing of the slots 4.

[0108] like Figure 8B As shown, the longer slot insertion portion of coil segment 16 is also arranged with the same slot spacing P1.

[0109] Correspondingly, the first receiving recess 38a of the inner torsion clamp 26 is formed according to the circumferential position of the short distal end 12d arranged in the groove 4, such that by bringing the stator 2 including the core 6 close to the inner torsion clamp 26 along the central axis of the inner torsion clamp 26, each of the first receiving recesses 38a can accommodate the corresponding short distal end 12d.

[0110] On the other hand, with each of the first receiving recesses 38a facing each other and the short distal end 12d to be received in each of the first receiving recesses 38a, the second receiving recess 38b is formed at a position offset circumferentially (left side in the figure) relative to the long distal end 14d to be received in the second receiving recess 38b. That is, the second receiving recess 38b is arranged at a position offset relative to the formation period of the first receiving recesses 38a.

[0111] In this embodiment, the offset of the second receiving recess 38b is half of the forming spacing P2 (= slot spacing P1) of the first receiving recess 38a.

[0112] exist Figure 8B In China, through cooperation with Figure 8A The positional relationship between the third receiving recess 38c and the second receiving recess 38b is shown in the same manner.

[0113] from Figure 8A and Figure 8B As can be seen from the comparison, similar to the first receiving recess 38a, the third receiving recess 38c is also formed according to its circumferential position at the distal end 16d, where the distal end 16d is the longer distal end of the coil segment 16 arranged in the slot 4, such that by bringing the stator 2 including the core 6 close to the inner torsion clamp 26 along the central axis of the inner torsion clamp 26, each of the third receiving recesses 38c can accommodate the corresponding distal end 16d. Incidentally, if the circumferential position of the inner torsion clamp 26 is adjusted so that each of the first receiving recesses 38a can accommodate the corresponding short distal end 12d at that position, then each of the third receiving recesses 38c can accommodate the corresponding distal end 16d.

[0114] In the torsion method of this embodiment, firstly, a stator 2 is prepared as a workpiece, wherein the stator 2 is a core 6 with coil segments inserted, and the stator 2 is placed in... Figure 5 The torsion device 18. Then, by driving the inner torsion clamp 26, the circumferential position of the inner torsion clamp 26 is moved to the position where one torsion begins.

[0115] like Figure 8C The position shown is where the long end 14d of the inner torsion clamp 26 and the second receiving recess 38b face each other.

[0116] As from and Figure 8A As can be seen from the comparison, in this state, the first receiving recess 38a is positioned offset relative to the short distal end 12d to be received in the first receiving recess 38a. The dashed line L indicates... Figure 8A The position of the distal end 14d in the state shown.

[0117] Next, from Figure 8C As shown in the diagram, the stator 2 is lowered by the operation of the drive mechanism 34 controlled by the controller 25, as indicated by arrow Z2. Figure 8D As shown, the longer distal end 14d of the modified coil segment 14 is partially inserted into the second receiving recess 38b. The stator 2 is positioned such that the shorter distal end 12d is not received in the first receiving recess 38a, and the distal end 16d is not received in the third receiving recess 38c, wherein the distal end 16d is the longer slot insertion portion of the coil segment 16 that becomes the neutral line. Figure 8D The vertical position of the distal end 16d in the state is shown by the dashed line in the figure. The setting of the descent amount can be stored in the non-volatile memory 25a of the controller 25.

[0118] Next, as Figure 8D As shown, while holding the distal end 14d partially housed in the second receiving recess 38b, the inner torsion clamp 26 is rotated a predetermined amount in the R1 direction to perform a single torsion.

[0119] Figure 8E The state after one torsion is shown. One torsion caused the long end 14d to tilt and deform.

[0120] In this embodiment, the predetermined amount of rotation of the inner torsion clamp 26 in one torsion is 1 / 2 of the formation spacing P2 of the first receiving recess 38a. That is, the rotation is performed with the aforementioned offset of the second receiving recess 38b. Strictly speaking, it is preferable to set the rotation amount by taking into account springback in addition to (1 / 2) × P2.

[0121] During a single twist, since the short distal end 12d and the distal end 16d are not inserted into the first receiving recess 38a and the third receiving recess 38c respectively, the short distal end 12d and the distal end 16d do not move. Therefore, according to the relationship with the above-mentioned amount of rotation, as Figure 8E As shown, after one twist, the short distal end 12d and the distal end 16d face the first receiving recess 38a and the third receiving recess 38c, respectively.

[0122] Therefore, in this state, by further lowering the stator 2 as shown by arrow Z2, the short distal end 12d and the distal end 16d can be inserted into the first receiving recess 38a and the third receiving recess 38c respectively so as to be accommodated in the first receiving recess 38a and the third receiving recess 38c.

[0123] In this state, a secondary torsion is performed to rotate the inner torsion fixture 26, wherein the rotation of the inner torsion fixture 26 is greater than a predetermined amount of rotation in the primary torsion. There may be a time lag between the primary and secondary torsions, or the operation may transition continuously from the primary to the secondary torsion.

[0124] When the stator 2 is lowered as described above, the long end 14d, which has already been twisted in one twist, will be further inserted into the second receiving recess 38b in a tilted deformed state. The entrance of each receiving recess (at least the second receiving recess 38b) of the inner twisting jig 26 is provided with an area that is machined into a circle (R shape) and is polished, so that even if the entrance of the second receiving recess 38b comes into contact with the insulating film, scratches can be prevented on the insulating film on the surface of the coil segment 14 during insertion.

[0125] like Figure 8G As shown, a second torsion is performed in the opposite direction to the first torsion. That is, the inner torsion clamp 26 is rotated in the opposite direction to the first torsion (arrow R2 direction).

[0126] The rotation amount of the inner torsion clamp 26 in the secondary torsion is more than one times the forming spacing P2 of the first receiving recess 38a. The rotation amount is not limited to an integer multiple of P2.

[0127] Figure 9 The structure of the input lead is shown when the above-mentioned secondary twist is completed.

[0128] In this embodiment, the rotation amount of the inner torsion clamp 26 during the secondary torsion is three times the forming spacing P2 of the first receiving recess 38a. Therefore, the short distal end 12d of the ordinary coil segment 12 is displaced by three times the forming spacing P2 of the first receiving recess 38a (= three slot spacings). On the other hand, regarding the long distal end 14d of the modified coil segment 14, the displacement caused by the primary torsion is offset by a secondary torsion in the opposite direction. Therefore, in the state where the long distal end 14d is upright perpendicular to the end face of the core 6, the long distal end 14d is at a position displaced by 2.5 times the forming spacing P2 of the first receiving recess 38a, that is, at a position where... Figure 9 The position shown corresponds to the gap 21 between the circumferentially connected portion 10 and the distal end.

[0129] The third receiving recess 38c is formed relative to the forming cycle of the first receiving recess 38a, without the "offset" that occurs with the second receiving recess 38b. Therefore, the distal end 16d of the coil segment 16 is arranged to be radially aligned with the row of the joint 10 after a secondary twist.

[0130] Furthermore, although not strictly necessary, in this embodiment, while performing secondary torsion using the inner torsion clamp 26, the outer torsion clamp 28 is also rotated in the opposite direction to the inner torsion clamp 26, allowing torsion to be performed on the coil segments in the second layer from the inner circumferential side. All receiving recesses 40a configured to accommodate the distal ends of the coil segments in the second layer are the same size as the first receiving recess 38a. This is because the distal ends arranged in the second layer are the distal ends for engagement.

[0131] Since the circumferential width of the gap 21 is greater than the circumferential width of the wire forming the modified coil segment 14, the rotation amount of the inner torsion clamp 26 during the first torsion (half the forming distance of the first receiving recess 38a) and the rotation amount of the inner torsion clamp 26 during the second torsion (more than twice the forming distance of the first receiving recess 38a) do not need to be precise. That is, it is sufficient to set the rotation amount such that when the second torsion is completed, the long end 14d of the modified coil segment 14 can rise from a position that does not interfere with the bending process for laying the modified coil segment 14 horizontally, as described later.

[0132] As described above, in this embodiment, when a single twist is performed while the long end portion 14d is housed in the second receiving recess 38b, the first receiving recess 38a and the second receiving recess 38b are formed such that the first receiving recess 38a is positioned offset relative to the short end portion 12d to be housed in the first receiving recess 38a, and after the single twist, the short end portion 12d is positioned approximately facing the first receiving recess 38a. Then, after performing a single twist only on the modified coil segment 14, a second twist is performed. Therefore, a single twisting jig (inner twisting jig 26) can be used to offset the position of the long end portion 14d from the row position of the joint 10, thereby easily obtaining the above-described horizontal connection structure.

[0133] Although this embodiment is configured to perform a secondary twist in the opposite direction to the primary twist, the same effect can be obtained even when rotating in the same direction. This is because the longer distal end 14d advances a predetermined amount longer by the primary twist compared to the shorter distal end 12d forming the joint 10. Incidentally, from a material cost perspective, performing a secondary twist in the opposite direction to the primary twist is more cost-effective because the bent portion 14-1 can be shortened, and thereby the longer distal end 14d of the modified coil segment 14 can also be shortened.

[0134] Furthermore, in this embodiment, although the respective distal ends of the coil segments are inserted into the corresponding receiving recesses by moving the stator 2, it is conceivable to move the torsion clamp side, or to move both the stator 2 and the torsion clamp.

[0135] Furthermore, during the secondary torsion, it is preferable to move the stator 2 closer to the inner torsion clamp 26 as the inner torsion clamp 26 rotates. At this time, at least one of the stator 2 and the torsion clamp 22 can move relative to the other in a direction along the central axis of the stator 2 and the torsion clamp 22. That is, contrary to this embodiment, while fixing the stator 2, the torsion clamp 22 side can be raised, or even the stator 2 can be lowered and the torsion clamp 22 side can be raised simultaneously.

[0136] After the second torsion, it becomes like Figure 9 The distal end 14d of the vertically standing input leads 14U1, 14U2, 14V1, 14V2, 14W1, and 14W2 shown is bent to accommodate contact with... Figure 1 The terminal components 15U, 15V, and 15W are shown for connection.

[0137] Reference Figure 10A and Figure 10B To describe the bending process.

[0138] For example, referring to input lead 14U1, the bending process for horizontal lying is performed by the following steps.

[0139] First, such as Figure 10A As shown, a bending guide member 50 configured to guide the bending of the root of the input lead 14U1 is inserted radially outward from the core 6, and in this state, the distal end of the input lead 14U1 is housed in the bending member 52 of the processing device.

[0140] Then, as Figure 10B As indicated by arrow Q, by tilting the bending member 52, the distal end 14d of the input lead 14U1 is bent so that it lies horizontally in the gap 21, thereby forming the outlet portion 14d-2. Then, by bending the bending member 52, the distal end of the outlet portion 14d-2 is axially bent toward the core, thereby forming the rising portion 14d-3.

[0141] This also applies to other input leads 14U2, 14V1, 14V2, 14W1, and 14W2.

[0142] Although the torsion of the innermost coil segment using the torsion jig 22 has been described above, it is also possible to use torsion jigs corresponding to each layer to torsion the portions of the coil segments protruding from the end face of the core 6 in other layers. Since there are no coil segments serving as input leads in other layers, the torsion jigs corresponding to other layers can only have the first receiving recess 38a spaced equally apart, and the second receiving recess 38b and the third receiving recess 38c are not required. The torsion direction of each layer is opposite to the torsion direction of the adjacent layer. Furthermore, it is preferable to use two torsion jigs to perform the torsion of two layers at a time.

[0143] Although in the above embodiments, the first receiving recess 38a to the third receiving recess 38c are formed as longitudinally extending grooves on the outer peripheral surface of the core 6, the receiving recesses can be formed on the inner peripheral surface of the clamp body 36 or on the inner side of the clamp body 36. Alternatively, the receiving recesses can be formed as holes that are not exposed on the side surface of the clamp body 36. Similarly, the receiving recess 40a can be formed on the inner peripheral surface, the inner side, the interior of the side surface, etc. of the clamp body 40.

[0144] Furthermore, although the above embodiments describe an example of laying the input lead horizontally in the circumferential gap 21 between the joints 10 of the ordinary coil segments and guiding the input lead from the inner circumferential side to the outer circumferential side, the present invention is not limited thereto, and it is conceivable that the input lead be guided from the outer circumferential side to the inner circumferential side. In this case, the receiving recesses corresponding to the first receiving recesses 38a to the third receiving recesses 38c can be provided on a torsion jig having a diameter corresponding to the outermost layer, and the receiving recesses corresponding to the reference can be placed on the torsion jig. Figures 8A to 8GThe torsion process described above is similar to the torsion process applied to the slot insertion portion in the outermost layer. Furthermore, the object to be laid horizontally in the gap 21 is not limited to the input lead.

[0145] Furthermore, although in the above embodiment only the long end 14d of the modified coil segment 14 is twisted in one twist, the long end 16d of the longer slot insertion portion of the coil segment 16 can also be twisted in one twist. In this variant example, similar to the long end 14d of the modified coil segment 14, the long end 16d of the longer slot insertion portion of the coil segment 16 (which becomes the far end of the neutral line) can be arranged at a position corresponding to the gap 21 between the joint portions 10.

[0146] Figure 11A An exemplary arrangement of the first receiving recess 38a to the third receiving recess 38c for such a single torsion is shown. The same reference numerals are used in conjunction with... Figures 8A to 8G The corresponding part of the structure shown.

[0147] exist Figure 11A In the example shown, with the first receiving recess 38a and the short distal end 12d to be received in the first receiving recess 38a facing each other, not only the second receiving recess 38b, but also the third receiving recess 38c is formed at a position offset circumferentially (left side in the figure) relative to the distal end 16d to be received in the third receiving recess 38c. That is, similar to the second receiving recess 38b, the third receiving recess 38c is also formed at a position offset relative to the formation period of the first receiving recess 38a.

[0148] The offset of the third receiving recess 38c and the second receiving recess 38b is 1 / 2 of the forming spacing P2 (= slot spacing P1) of the first receiving recess 38a.

[0149] Figure 11B It shows the use of Figure 11A Part of the torsion operation of the internal torsion clamp shown.

[0150] By using reference Figure 11A The described internal torsion clamp 26, when the distal end 14d is received in the second receiving recess 38b during a single torsion, as... Figure 11B As shown, the longer distal end 16d, which serves as the longer slot insertion portion of the coil segment 16, can also be simultaneously accommodated in the third receiving recess 38c. Therefore, the distal end 16d can also be a single-twist object.

[0151] There are methods for welding the end of the neutral wire to a single plate when connecting the neutral wire. However, if the height of the end of the conductor circumferentially adjacent to the neutral wire (joint 10) is equal to or higher than the height of the end of the neutral wire, the plate may interfere with the end of the adjacent conductor or the insulating film. Although this problem is particularly significant in constructions that include a 1 / 2 pitch portion as in this embodiment, this problem can be avoided by twisting the distal end, which is the neutral wire, in a single twist as described above, thereby arranging the distal end in the gap 21 of the joint 10.

[0152] Furthermore, in the above embodiments, such as Figure 6 As shown, the first receiving recess 38a, the second receiving recess 38b, and the third receiving recess 38c have different depths. However, in both the single-twist and double-twist cases, when the torsion is performed, the distal end housed in each receiving recess does not need to be inserted to reach the bottom of the receiving recess. Therefore, each receiving recess can be formed to a depth deeper than required to accommodate the corresponding distal end. For example, the depth of each receiving recess can be... Figure 6 The deepest second receiving recess 38b has the same depth. In this case, all receiving recesses have the same shape. Furthermore, the first receiving recess 38a and the third receiving recess 38c can be formed at equal intervals with a spacing of P2, and as referenced... Figure 8A The second receiving recess 38b can be formed at a position offset by 1 / 2 of the spacing from the position according to the spacing of P2.

[0153] The preferred embodiments of the present invention have been described above. However, the present invention is not limited to these specific embodiments, and various modifications and variations are conceivable. The above-described structures can be implemented by extracting only a portion of the above-described structures, and these variations can be applied in any combination as long as they do not conflict with each other. The effects described in the embodiments of the present invention are merely illustrative of the most preferred effects produced by the present invention, and the effects of the present invention are not limited to those described in the embodiments of the present invention.

[0154] [List of reference numerals]

[0155] 2. Stator

[0156] 4 slots

[0157] 6 cores

[0158] 10 Joint

[0159] 12. Ordinary coil segment

[0160] 12d Short distal end

[0161] 14 Modified coil segment

[0162] 14d long distal end

[0163] 16. A coil segment having a distal end serving as the neutral line.

[0164] 21 gap

[0165] 22 Torsion clamp

[0166] 25 Controllers

[0167] 26 Internal Torsion Clamp

[0168] 28 External Torsion Fixture

[0169] 36, 40 Fixture body

[0170] 38a First receiving recess

[0171] 38b Second receiving recess

[0172] 38c Second receiving recess

Claims

1. A method for twisting a coil segment, comprising: In the preparation of a workpiece, multiple coil segments are inserted into multiple slots arranged circumferentially along a core configured to form a stator of a rotary motor. The distal ends of each coil segment, protruding from the end face of the core toward the insertion direction, form multiple layers radially within the core. In one of these layers, a short distal end and a long distal end are arranged. The short distal end is any distal end to be engaged with the distal ends of other coil segments, and the long distal end protrudes from the end face of the core and is longer than the short distal end. The distal ends of the plurality of coil segments are twisted by performing the following steps respectively, such that when viewed along the circumferential direction, the long distal ends are arranged between adjacent short distal ends: With the distal end at least partially inserted into the second receiving recess of the torsion clamp and the distal end not inserted into the first receiving recess of the torsion clamp, a torsion is performed, in which the torsion clamp rotates a predetermined amount. The torsion clamp includes a first receiving recess configured to receive the distal end and a second receiving recess configured to receive the distal end. One of the workpiece with the plurality of coil segments inserted and the torsion fixture is moved relative to the other of the workpiece and the torsion fixture along the axial direction of the workpiece and the torsion fixture, so that the workpiece is brought closer to the torsion fixture, such that the short distal end is at least partially inserted into the first receiving recess while the long distal end remains at least partially inserted into the second receiving recess, and then... With the long end at least partially inserted into the second receiving recess and the short end at least partially inserted into the first receiving recess, a secondary twist is performed, wherein the amount of rotation of the twisting clamp in the secondary twist is greater than the predetermined amount.

2. The method for twisting the coil segment according to claim 1, in, Before performing the first twist, with the distal end at least partially inserted into the second receiving recess of the twisting clamp, each of the first receiving recesses is positioned at a circumferentially offset position relative to each of the distal ends to be received by the first receiving recess, and After the first twist is performed, each of the first receiving recesses is positioned substantially opposite to each of the short distal ends to be received by the first receiving recess.

3. The method for twisting the coil segment according to claim 1, in, The layer with the long end is the innermost or outermost layer in the radial direction.

4. The method for twisting the coil segment according to any one of claims 1 to 3, in, In the first twist, the predetermined amount of rotation of the torsion clamp is approximately 1 / 2 of the spacing of the slots, and in the second twist, the amount of rotation of the torsion clamp is more than twice the spacing of the slots.

5. The method for twisting the coil segment according to any one of claims 1 to 3, in, The second torsion is performed to rotate the torsion clamp in the opposite direction to the first torsion.

6. A torsion device, wherein a torsion clamp can be attached to the torsion device. in, The torsion clamp is configured to circumferentially torsion the distal ends of a plurality of coil segments protruding from the end face of the core, the plurality of coil segments being inserted into a plurality of slots arranged circumferentially along the core, the distal ends of each coil segment protruding from the end face of the core toward the insertion direction forming a plurality of layers in the radial direction of the core, the torsion clamp comprising: cylindrical body; First receiving recesses, circumferentially spaced and formed on the body, are configured to respectively receive short distal ends, said short distal ends being any distal end to be engaged with the distal ends of other coil segments; and Second receiving recesses are formed circumferentially at intervals on the body and configured to respectively receive a long distal end, wherein the long distal end is any distal end that protrudes from the end face of the core and is longer than the short distal end. The first and second receiving recesses are arranged such that, with the long distal end being received by the second receiving recess before twisting, each of the first receiving recesses is positioned at a circumferentially offset position relative to each short distal end to be received by the first receiving recess. The torsion device includes: A rotary drive mechanism configured to rotary drive the torsion clamp; A drive mechanism configured to move one of the core and the torsion clamp into which the plurality of coil segments are inserted relative to the other of the core and the torsion clamp along the axial direction of the core and the torsion clamp; A controller configured to control the rotary drive mechanism and the drive mechanism such that, when viewed along the circumferential direction, the longer distal end is positioned between adjacent shorter distal ends by performing the following steps respectively: With the long end at least partially inserted into the second receiving recess and the short end not inserted into the first receiving recess, a first twist is performed, in which the twisting clamp rotates by a predetermined amount; then, one of the core with the plurality of coil segments inserted and the twisting clamp is moved relative to the other of the core and the twisting clamp along the axial direction of the core and the twisting clamp, so that the core is brought closer to the twisting clamp, such that with the long end at least partially inserted into the second receiving recess and the short end at least partially inserted into the first receiving recess, and then, with the long end at least partially inserted into the second receiving recess and the short end at least partially inserted into the first receiving recess, a second twist is performed, in which the rotation of the twisting clamp in the second twist is greater than the predetermined amount.

7. The torsion device according to claim 6, wherein, With the long distal end accommodated by the second receiving recess before twisting, the offset in the circumferential direction between each of the first receiving recesses and each short distal end to be accommodated by the first receiving recesses is approximately 1 / 2 of the spacing of the grooves.

8. The torsion device according to claim 6, in, The diameter of the torsion clamp corresponds to one of the multiple layers that is the innermost or outermost layer in the radial direction, and the long end is arranged in one of the layers.

9. The torsion device according to claim 6, in, In the first twist, the predetermined amount of rotation of the twisting fixture is approximately 1 / 2 of the spacing of the slots, and in the second twist, the amount of rotation of the twisting fixture is more than one time the spacing of the slots.

Images