WO2017178004A1

WO2017178004A1 - Rolling-bearing cage and assembly method for a rolling-bearing cage

Info

Publication number: WO2017178004A1
Application number: PCT/DE2017/100218
Authority: WO
Inventors: Christoph Meder
Original assignee: Schaeffler Technologies AG & Co. KG
Priority date: 2016-04-12
Filing date: 2017-03-20
Publication date: 2017-10-19
Also published as: DE102016206072A1; DE102016206072B4

Abstract

A rolling-bearing cage 14 is formed by a plurality of segments 1. The provision of pressure-resilient structures 20 on the free ends 6.1 and 6.2 of the side plates 2 of the segments 1 produces a rolling-bearing cage 14 which has a stable annular form despite the use of segments 1, thereby permitting, in a simple manner, a wear-free action, even for segmented rolling-bearing cages 14. Also disclosed are methods for producing segmented rolling-bearing cages.

Description

Name of the invention

Rolling bearing cage and mounting method for a rolling bearing cage

TECHNICAL FIELD The invention relates to a roller bearing cage and a mounting method for such a rolling bearing cage, which has a circumference of pitch circle diameter D x π of at least two segments mounted in the circumferential direction of a roller bearing to a completely closed rolling bearing cage, each segment having a first side plate and a second side plate and at least two webs extending therefrom, each extending between and interconnecting the two side plates, each segment comprising at least one closed pocket formed by two circumferentially immediately adjacent webs and the side plates and at least one open U-shaped pocket formed by between two free ends of different side panels and a web.

Rolling bearings usually consist of an inner ring, an outer ring and a plurality of rolling elements arranged between these races. In order to achieve a uniform load distribution, based on the circumference of Wälzla- gers equally distributed arrangement of the rolling elements and to prevent contact of the rolling elements with each other, the rolling elements are usually performed in a roller bearing cage. In large rolling bearings, which are used for example in rolling mills and in wind turbines, the rolling bearing cages are often formed as a bolt cages or as window cages. A bolt cage comprises two closed side rings and a plurality of bolts arranged uniformly distributed on the circumference between the side rings. On the bolt is in each case provided with a central bearing bore Wälz- body rotatably mounted. A window cage also has two closed side rings and a plurality of circumferentially equally distributed between the side rings arranged on axial webs. The side rings and the axial webs include several commonly referred to as windows or pockets spaces in each of which a rolling element is guided. Depending on the design and function of the roller bearing, the rolling elements may be cylindrical rollers, tapered rollers or barrel rollers.

Notwithstanding the closed design, a window cage may also be formed of cage segments, which are either connected to each other or at least in the circumferential direction of the cage in contact with each other. In addition, also bare cage spacers are known, which are arranged without being in contact with each other as separation and guide elements between the rolling elements.

From DE 102009016017 B4 reduced to a separating and guiding element cage intermediate piece of a rolling bearing is known which has two axially outer fork-shaped guide body with concave abutment surfaces which are interconnected via a radially aligned planar axial web. In the mounted state of the respective rolling bearing, the cage spacers are circumferentially arranged in each case between two rolling elements and guided with the base of the guide body on the raceway of the inner ring.

In DE 102012223316 B3 a similar cage intermediate piece of a rolling bearing is described, which has in addition to the fork-shaped guide bodies two the two rolling elements frontally partially encompassing side windows. The side windows are connected to each other via the axial web, but are not in contact with the side windows of the circumferentially adjacent cage intermediate pieces. The side windows serve for the lateral guidance of the respective cage segment via the rolling elements guided in sideboards in one of the races, and each have at their radial edges a bulge for sliding guidance on the raceways of the races. In contrast, a box-shaped cage segment of a roller bearing is disclosed in DE 10201 1087864 A1, in which two axial webs provided with fork-shaped guide bodies are connected to each other at the ends via a circumferential web. In the assembled state of the respective rolling bearing a rolling element is disposed within the cage segment, and two other rolling elements are based on the circumference of the rolling bearing on the outside in each case on one of the axial webs of the cage segment. In the respective rolling bearing thus circumferentially alternately each guided within a Käfigseg- ment rolling elements and a frontally guided between two cage segments rolling elements are arranged alternately.

In rolling bearings with said cage segments, the packing density of the rolling elements in the rolling bearing is limited by the arrangement of the guide body on the axial webs and, for example, lower than in corresponding rolling bearings with pin cages. In addition, due to the lack of support of the cage segments in the circumferential direction of the roller bearing, local compressions of rolling elements and cage segments can occur, which are vibrationally erected and disassembled and can lead to increased wear on the contact surfaces between the rolling elements and the cage segments ,

On the other hand, DE 102013207301 A1 and DE 102013220833 A1 disclose cage segments of roller bearings, each of which has two side disks approximately halfway around the two rolling elements, which are connected to one another via a radially aligned, flat axial web. On the axial web of the respective cage segment guide body with stop surfaces for guiding the associated rolling elements are arranged. While the cage segment according to DE 102013207301 A1 for radial guidance provided with outer sliding, arranged on the axial web guide finger, are in the cage segment according to DE 102013220833 A1, the side windows for this purpose with radially outer bulges or Provided contact elements. The arrangement of the starter body on the axial webs, the circumferential packing density of the rolling elements is also limited to rolling bearings, which are provided with these versions of the cage segments. Since the cage segments are in the mounted state of the respective rolling bearing but in the circumferential direction of the bearing facing end faces with the adjacent cage segments in contact, a uniform distribution of the rolling elements over the circumference is ensured in the corresponding rolling bearings. In contrast, the non-prepublished DE 102015200381 A1 proposes a cage segment of a rolling bearing similar to the cage segment according to DE 102013220833 A1, in which the side windows are connected to one another by two round bolts arranged radially staggered. The axial webs formed in this way serve, on the one hand, to connect the two side disks and, on the other hand, to guide the two associated rolling bodies. Due to the free space between the round bolts, equipped with such cage segments bearings has increased packing density of the rolling elements and thus a higher load rating. However, due to the relatively large contact surfaces between the round bolts and the rolling elements, an unfavorably high rolling resistance and increased wear can result.

In addition, from the unpublished DE 102015206533 A1 a segment for a rolling bearing cage of a rolling bearing is known, which is composed of a plurality of Eintaschensegmenten, each of these Eintaschensegmente receives a rolling body. Such a one-pocket segment consists of two side plates arranged parallel to one another and two plate-shaped webs aligned parallel to the longitudinal axis of the respective rolling element, wherein the side plates and the webs are firmly connected to one another. At the mutually facing surfaces of the side plates contact elements for the frontal starting of the respective rolling elements are formed, and the plate-shaped webs each have in the circumferential direction of the Cage directed projections on which radial contact surfaces are formed for the respective rolling elements.

Finally, from the documents DE 102009037422 A1 and EP 2264325 A1 segments for a segmented roller bearing cage with 4 pockets, from DE 1026577 A1 cage segments with two pockets, and from the already mentioned DE 10201 1087864A1 cage segments each having a pocket known. With regard to the known segmented rolling bearing cages, it can be stated that the fewer rolling elements can be arranged in a cage segment, the greater the number of cage components which are necessary for constructing a complete rolling bearing cage. This has a detrimental effect on manufacturing costs, warehousing, transportation and cage assembly. Although in Mehrtaschenkäfigsegmenten, so for example a cage segment with four pockets, this disadvantage compared to a Eintaschenkäfig significantly reduced, but increases with increasing number of pockets, the tendency of the rolling elements and the cage segments in the rolling bearing. In addition, it should be noted that the more pockets a cage segment has, the higher the impact energy with which such cage-filled cage segment can strike in operation against an immediately adjacent cage segment when overcoming a circumferential clearance. As a result, the cage wear in cage segments with many pockets is comparatively high. Finally, especially in large-diameter bearings, such as with a diameter of more than 0.5 meters, the respective cage segment the heavier and thus less easy to transport and assemble, the more pockets has such a cage segment.

Finally, in the generic, but not yet published DE 102015219277 A1 a formed from segments roller bearing cage is given, which has two side plates and two webs which are fixedly connected to each other, wherein the webs are parallel to the axis of rotation of the rolling elements of the Rolling bearing extend, and in which the side plates and the webs as well as DE 102015206533 A1 form a pocket for receiving a rolling element. In contrast to DE 102015206533 A1, it is provided for each segment according to DE 102015219277 A1 that the free ends of the side plates extend on both sides of the pocket in the circumferential direction of the roller bearing with a free rag length R _L > WK _D such that these together with one each each of the two webs form a half, substantially U-shaped pocket for receiving an immediately adjacent rolling element, wherein WK _D corresponds to the diameter of a rolling element inserted in the half pocket. The fact that the segments ultimately only need to take up a rolling element, compared to segments which must accommodate more than one rolling element, the action of generic segments in the assembly improves and the impact energy, with such, filled with rolling elements segment in operation striking an immediately adjacent segment in overcoming an unavoidable, caused by tolerance deviations circumferential play strikes, significantly reduced.

Due to the fact that, in the case of roller bearing cages formed from segments, these segments are unconnected to one another, it can happen during operation of such a roller bearing that the segments no longer run on an ideal circular path or the segments tilt against one another or shift against one another, which is disadvantageous. since this leads to increased friction or heat development in the rolling bearing. The invention is therefore based on the object to provide a rolling bearing cage formed from segments, which always ensures an ideal alignment of the segments in a simple manner despite the use of loose segments and which is also easy to implement. This object is achieved by the device features of claim 1 and procedurally by the features of claim 7. Advantage- Advantageous embodiments and further developments of the invention can be taken from the dependent claims.

The advantageous effects of the invention are based on the fact that, in the case of roller bearing cages formed from segments, at least one free end of a first side plate of at least one segment and a free end of a second side plate of one or another segment press a circumferential direction of the roller bearing cage. has elastic structure, and that in the unassembled state, the sum of the mean arc lengths of all the rolling bearing cage forming segments is greater than the circumference of the pitch circle diameter DX TT, which results after assembly of these segments to a rolling bearing cage. Namely, if such segments mounted to a rolling bearing cage, it is necessary to deform the pressure-elastic structures at the free ends of the side plates in the circumferential direction, so that upon completion of the assembly, the acting restoring forces of the pressure-elastic structures brace the assembled segments of the rolling bearing cage against each other and ensure the cohesion of the segments of the rolling bearing cage.

The formation of the pressure-elastic structures is particularly simple if they form a one-piece unit together with the respective side plates.

The formation of pressure-elastic structures is very simple if they are formed by a mere cut or breakthrough in the respective side plate.

A mutual displacement of mounted segments in the direction of the axis of rotation of the rolling bearing is excluded if means are provided on the side plates, which exclude a relative movement transversely to the circumferential direction between immediately adjacent segments in a rolling bearing cage formed from segments. For this purpose, shoulders are preferably provided at the free ends of a first segment which extend in the circumferential direction. tion of the rolling bearing cage and cover the free ends of a second, immediately following the formation of a rolling bearing cage segment when the rolling bearing cage is endmoniert. The mounting of a roller bearing cage is particularly simple if, in a first step, at least n-1 segments are arranged on a raceway of an inner ring or an outer ring of a rolling bearing, where n represents the maximum number of segments from which the rolling bearing cage after assembly of all segments is formed and after assembly has a circumference of pitch circle diameter D x π, when then the arranged on the track segments are pushed together in the circumferential direction, so that forms a gap between a first and a last resting on the track segment, and if that or the remaining segments are inserted into the gap.

A particularly light and force-free insertion of the missing segments is given when, after the pushing together of the segments, the gap is further increased by the action of force on the segments already laid on the track.

The missing segments automatically find their position when n-2 segments are arranged on the track, if in the gap, which results after pushing the already arranged on the track segments, the two missing segments are arranged so that, on the one hand the first missing segment with a first and the second missing segment with a last of the already laid on the track segments and further the missing segments are in physical contact with each other and that the two missing segments between them enclose an angle α, and then the pressed against the track of both missing segments against the effect of the segments already placed on the track by applying a force to the free ends of the missing links. the segments is applied, with which they are in physical contact with each other.

Brief description of the figures

Show it:

1 shows a segment according to the invention, FIG. 2 shows a further embodiment of a segment;

3 is a side view of segments,

Fig. 4 is an assembly view, and

Fig. 5 is a further assembly view.

MODES FOR CARRYING OUT THE INVENTION The invention will now be explained in more detail with reference to the figures.

In Fig. 1, a segment 1 is shown, which forms a rolling bearing cage together with further, identically formed segments. This segment 1 is formed by two, a mutual distance A1-compliant side plates 2 and two webs 3, wherein the webs 3 extend transversely to the longitudinal extent of the side plates. The segment 1 shown in Figure 1 is made in one piece from cast steel and can be modular in another not particularly illustrated embodiment, for example, by the separate side plates 2 and webs 3 are subsequently connected by welding, gluing or screws to the segment 1 shown , 1, the two webs 3 hold a mutual distance A2 in the direction of the longitudinal extension of the side plates 2 or in the case of a rolling bearing cage formed from these segments 1 in the circumferential direction of this rolling bearing cage. By this arrangement of the two side plates 2 and the two webs 3, a pocket 4 is formed, which serves for receiving a rolling element (not shown in Fig. 1).

1 can be clearly seen that in the segment 1 shown, the two side plates 2 are continued in the circumferential direction of the rolling bearing cage formed from the segments beyond the pocket 4, that is based on the webs 3 with a free Raglänge RL side projecting, which is greater than half the diameter of the rolling elements, which are inserted into the segment 1 and guided by this.

Although rolling elements are not shown in FIG. 1, it should be noted at this point that the pocket 4 according to FIG. 1 receives a conical rolling element. Is the segment 1 shown in Fig. 1 another segment to form a rolling bearing cage juxtaposed, of two U-shaped, each of a web 3 and extending beyond in the circumferential direction of the rolling bearing cage side plates 2 different segments 1 another, two half-pockets Bag 13, which also accommodates a conical rolling element, is provided for 13 different segments.

Since the segment 1 shown in FIG. 1 is intended to receive conical rolling bodies which indeed have a large and a small diameter, the free rag length R _L of the side plate 2 located in the foreground is somewhat smaller than that in the background of FIG 1 lying side plate 2. In the side plates 2 holes 5 are introduced, which serve the lubricant supply of arranged in the segment 1 rolling elements.

The side plates 2 close in the circumferential direction of the rolling bearing cage with free ends 6.n. In order to effect a support of the segment 1 on the raceway and / or the Borden of bearing rings, not shown, rounded at the free ends 6.n trained, transversely to the longitudinal direction of the side plates 2 extending projections 7 are provided, which from the side plates 2 with Protrude supernatant.

The free ends 6.1. 6.2 both side plates 2 are each exempted by one, ending in a hole 5.1 L-shaped section 8. This release of the free ends 6.1. 6.2 causes the leg 9 formed by the cuts 8 have a compressive elastic compliance in the direction of the longitudinal extension of the side plates 2, so spring when the free ends 6.1 and / or 6.2 are applied with force that presses against these ends ,

For the sake of completeness, it should be pointed out that in other embodiments, not shown, pressure-elastic structures 20 at all free ends 6.1 -6.4 or only at the free ends 6.1 and 6.4 or 6.2 and 6.3 by the introduction of corresponding cuts 8 in the side plates 2 of the segment shown can be provided.

Due to the fact that a roller bearing cage, be it in one piece or formed of a plurality of segments 1, always describes a circular ring which is arranged coaxially to the axis of rotation of the bearing results in a built up of segments 1 roller bearing cage, that its side plates 2 rounded or curved. If segments 1 of the same length and a given pitch circle diameter D of a rolling element set are to have the length of the segments 1 forming the rolling bearing cage, the segments 1 and their side plates 2 must be in consideration of the required curvature or rounding the mean, centrally between the Endungspaaren the free ends 6.1, 6.2 and 6.3, 6.4 of the two side plates 2 extending radian measure BM authoritative. These relationships are clearly highlighted in Fig. 1 by the representation of the segment 1, the mean radian measure BM and the axis of rotation DA.

The segment 1 shown in FIG. 2 differs from the segment 1 shown in FIG. 2 in that there the pressure-elastic structures 20 of the free ends 6.1, 6.2 are formed by mushroom-shaped openings 10 introduced into the respective side plates 2 in the illustration according to FIG. 2, only the opening 10 at the free end 6.2 is visible. In addition, the other free ends 6.2, 6.4 of this segment 1 are provided with shoulders 1 1, which extend in the longitudinal direction of the side plates 2 of the segment 1 shown and which adjacent the free ends of a forming a rolling bearing cage, not shown in Fig. 2 Seg - Over element to exclude relative movements of adjacent segments in the direction of the axis of rotation DA.

As the illustration of FIG. 2 can be clearly seen, are inserted into the segment 1 shown there rolling elements 12.n, wherein a rolling element 12.1 in the closed pocket 4 and the other rolling elements 12.2 and 12.3 in the two U-shaped, from the side plates 2 and the webs 3 formed half-pockets 13 are arranged.

In Fig. 3, a formed from segments 1 of FIG. 1 rolling bearing cage 14 is shown, which is arranged between an inner ring 15 and an outer ring 16 of a rolling bearing 17 and which is already equipped with rolling elements 12. To guide the roller bearing cage 14 and the segments 1, the projections 7 of the side plates 2 are supported in this embodiment both on the inner ring 15 and on the outer ring 16 of the rolling bearing 17.

Although only two complete segments 1 are shown in FIG. 3 for reasons of clarity, this illustration clearly shows that the Half pockets 13 of two different, to form a rolling bearing cage 14 sibling segments 1 always record a rolling element 12 between them. It can also be seen from the illustration according to FIG. 3 that the free ends 6, n of all segments 1 are in physical contact with one another when the roller bearing cage 14 is finally mounted. This is due to the fact that the sum of the mean arc length BM (FIG. 1) of all segments 1 used to form the roller bearing cage 14 according to FIG. 3 is greater than the circumference of the pitch circle diameter D x π in the not yet assembled state and that after assembly all segments 1 to a roller bearing cage 14, the respective free ends 6.2 (6.1), which have a pressure-elastic structure 20 (8, 9) are compressed and clamp with their acting return forces the roller bearing cage 14 to form a closed ring.

A simple example of the mounting of a roller bearing cage 14 formed from segments 1 is shown in FIG. This rolling bearing cage 14 is formed by four (n = 4) segments 1. The pressure-elastic structures 20 at the free ends 6.1 are indicated by mere arcs. Three (n-l) of these segments 1 are arranged around the inner ring 15, wherein these segments 1 are pushed together powerless and leave a gap 18 between a first segment 1 .1 and a last segment 1 .3. As a result, the circumference resulting from the pitch diameter D x π is smaller than the sum of the mean arc lengths BM of all four segments 1 .1 to 1 .4 forming this rolling bearing cage 14, even if the three are not aligned in a row Segments 1 .1 to 1 .3 the mean radians BM 1 of the gap 18 is smaller than the mean radians BM of the not yet used segment 1 .4.

On this basis, the rolling bearing cage completing the segment 1 .4 can be inserted or pressed into the gap 18 in the direction of arrow P. However, in order to facilitate the insertion or pressing in of the still missing segment 1 .4, the segments 1 .1 to 1 .3 already arranged around the inner ring 15 can already be counterbalanced by applied forces K. the compressed and the pressure-elastic structures 20 at the free ends

6.1 be set back so far that the mean radian measure BM 1 of the gap 18 is at least equal to the mean radian BM of the segment to be used 1 .4.

Is the onset of the missing segment 1 .4 completed, the restoring forces acting on the free ends 6.1 of the segments 1 .1 to 1 .4 ensure that the segments 1 .1 to 1 .4 form an automatically cohesive, closed ring.

FIG. 5 shows another way of mounting a roller bearing cage 14 formed from n segments 1 according to FIG. 1. N-2 of these segments 1 are placed on a raceway 19 of an inner ring 15 shown only schematically and pushed together without power, so that a gap 18 forms between a first applied and a last applied segment 1 .1, 1 .2. As previously stated, in the not yet assembled state, even in the embodiment in FIG. 5, the sum of the mean arc lengths BM of all segments 1 .n forming these roller bearing cage 14 is greater than the circumference of the pitch circle diameter D x TT. Consequently, the mean radian of the gap 18 between the first and the last segment 1 .1 and 1 .2 is also smaller than the double mean radian measure BM of a segment 1 .n. In order to complete the rolling bearing cage 14, then the two missing segments 1 .3 and 1 .4 are arranged in the gap 18 so that on the one hand the first missing segment 1 .3 with a first and the second missing segment 1 .4 a last of the already placed on the inner ring 15 segments 1 .1 and

1 .2 and further the missing segments 1 .3, 1 .4 are in physical contact with each other and that the two missing segments 1 .3, 1 .4 between them enclose an angle α. Basically, the two missing segments 1.3, 1 .4 are arranged roof-shaped in the gap 18. Now acts a force K on the free ends 6.1 to 6.4, ie on the rooftop, fold or swing the missing segments 1 .3 and 1 .4 and so complete the roller bearing cage 14. At the same time folding or pivoting onto the inner ring 15 or on its track 19, the pressure-elastic structures of the free ends 6.1, 6.2 of all segments 1 .n compressed and ensure by their restoring forces in the circumferential direction of the roller bearing cage 14 that the rolling bearing cage 14th forming segments 1 .n are braced against each other.

Are, as already shown in Figs. 1 to 4, the free ends formed 6.n or the transitions from the projections 7 to the free ends 6.n rounded, the pivoting or folding is favored, because it then to an Ab - Rolling movement between the missing and already arranged on the inner ring 15 segments 1 .1 and 1.3 or 1.2 and 1 .4 comes.

LIST OF REFERENCE NUMBERS

1 segment

2 side plates

3 bars

4 bag

5, 5.1 hole

6.n free ends

7 protrusions

8 cut

9 thighs

10 breakthrough

1 1 shoulder

12 rolling elements

13 half-pockets

14 rolling bearing cage

15 inner ring

16 outer ring

17 rolling bearings

18 gap

19 career

20 pressure-elastic structure

Claims

Rolling bearing cage having at least two segments 1, mounted in the circumferential direction of a rolling bearing 17 to a fully closed roller bearing cage 14 have a circumference of pitch circle diameter D x π, each segment 1 a first side plate 2 and to this a distance A1 compliant second side plate 2 and has at least two webs 3, each extending between the two side plates 2 and connect them together, each segment 1 at least one, formed by two circumferentially immediately adjacent webs 3 and the side plates 2, closed pocket 4 and at least one of two free ends 6.n different side plates 2 and a web 3 formed, open U-shaped pocket 14 provides, characterized in that at one, formed from segments 1 roller bearing cage 14 at least one free end 6.1 a first side plate 2 of at least one segment. 1 and a free end 6.2 of a second side plate 2 of this or another segment 1 has a pressure-elastic structure 20 in the circumferential direction of the rolling bearing cage 14, and that in the unassembled state, the sum of the mean arc lengths BM of all the rolling bearing cage 14 forming segments 1 greater than the circumference of the pitch circle diameter DX TT is. Rolling bearing cage according to claim 1, characterized in that the respective pressure-elastic structure 20 is an integral part of the respective side plate 2. Rolling bearing cage according to claim 2, characterized in that the respective pressure-elastic structure 20 is formed in the respective side plate 2 of a section 8 or an opening 10. Rolling bearing cage according to one of claims 1 to 3, characterized in that on the side plates 2 means 1 1 are provided which exclude a relative movement transversely to the circumferential direction between immediately adjacent segments 1 in a rolling bearing cage 14 formed from segments 1. Rolling bearing cage according to claim 4, characterized in that at the free ends 6.3, 6.4 of a first segment 1 means 1 1 are provided which extend in the circumferential direction and on which the free ends 6.1, 6.2 of a second, immediately following segment 1 abut when the Rolling bearing cage 14 has been formed from segments 1. Rolling bearing cage according to one claims 1 to 5, characterized in that the rolling bearing cage 14 is such for a slewing bearing with a pitch circle diameter D of at least half a meter. Assembly method for a roller bearing cage according to one of claims 1 to 6, characterized in that in a first step at least n-1 segments on a track 19 of an inner or outer ring 15, 16 of a rolling bearing 17 are arranged, where n for the maximum number of segments 1, from which the roller bearing cage 14 is formed after assembly of all segments 1 and after assembly has a circumference of pitch circle diameter DX TT that then arranged on the track 19 segments 1 are pushed together in the circumferential direction, so that a gap 18 forms between a first and a last of the only applied segments 1, that or the remaining segments 1 .3 and / or 1 .4 are inserted into the gap 18. Assembly method according to claim 7, characterized in that after the pushing together of the segments 1, the gap 18 is further increased by force K on the only applied segments 1. Mounting method according to claim 7, characterized in that n-2 segments 1 on the track 19 of a bearing ring 15, 16 are arranged that in the gap 18, which results after the pushing together of the already arranged on the track 19 segments 1, the both missing to complete the roller bearing cage 14 segments 1 .3, 1 .4 are arranged so that on the one hand, the first missing segment

1 .3 with a first and the second missing segment 1 .4 with a last of the already laid on the track segments 1 .1, 1 .2 and further the missing segments 1 .3, 1 .4 are in physical contact with each other and that the two missing segments 1 .3, 1 .4 between them enclose an angle α, and that then the two missing segments 1 .3, 1 .4 pressed against the action of the already laid on the track segments 1 against the raceway 19 , by adding to the free ends 6.1 to 6.4 of the missing segments 1 .3, 1 .4, with which the missing segments 1 .3,

1 .4 are in physical contact with each other, a force K is applied.