Needle roller

Abstract

A needle roller (7) comprises a hollow-cylindrical supporting core (1) with a longitudinal axis (5) and a supporting core cylinder wall (10) having an outer surface (18), and comprises a needle sleeve (2) which has a hollow-cylindrical needle sleeve body (21) and a plurality of outward-projecting needle elements (20) fastened to the needle sleeve body. The needle sleeve lies on the outer surface of the supporting core cylinder wall. The supporting core cylinder wall comprises a first main wall region (12a) extending in the axial direction and a second main wall region (12b) extending in the axial direction, each of which has a main wall thickness (W1), and a recessed region (14) extending in the axial direction, with a wall thickness (W2) which is smaller than the main wall thickness (W1). The recessed region is located in the axial direction between the first main wall region and the second main wall region. The recessed region leads to a reduction in the weight of the supporting core compared to a supporting core without a recessed region.

Description

[0001]Needle roller The present invention relates to a needle roller, in particular a needle roller for use in a perforating or fibrillating device. To perforate film webs, for example, in a perforating device, the film webs are guided over a needle roller with outwardly projecting needle elements. The respective film web is perforated by guiding the film web over the needle roller and rolling the needle roller along the film web through the needle elements. During fibrillation, plastic webs are similarly guided over a needle roller to produce fibrillated films, film tapes, and fibers. A needle roller, as typically used for perforating film webs or for fibrillation, must have high strength and stability as well as high resistance to wear.In addition, such needle rollers are ideally heat-resistant to enable them to be used for processes carried out at high temperatures, such as hot perforating. Accordingly, needle rollers suitable for perforating and fibrillating are usually made of metal. Plastic can also be used for applications involving low forces. Such needle rollers typically comprise a needle sleeve with attached outwardly projecting needle elements, which is arranged on a hollow cylindrical support core. The hollow cylindrical support core serves, on the one hand, to position the needle roller on a shaft and, on the other hand, to support and stabilize the needle sleeve arranged on an outer surface of the support core from the inside. The hollow cylindrical support core is made, for example, of stainless steel with a wall thickness of several millimeters. Such a needle roller typically weighs several kilograms.On the one hand, this has a negative impact on energy consumption when transporting several such needle rollers, especially since a large number of such needle rollers are usually transported at once. On the other hand, such a high mass has a negative impact on the moment of inertia of the needle roller, which leads to high energy consumption for rotating or braking the needle roller or possibly to great stress on the film being processed if the needle roller is driven by the film web. Against this background, the object of the invention is to provide a needle roller of the type mentioned at the outset that has a reduced weight without having to accept significant disadvantages with regard to the stability, strength, heat resistance, and wear of the needle roller. This object is achieved by the needle roller according to the invention, as defined in independent patent claim 1.Particularly advantageous developments and refinements of the needle roller according to the invention emerge from the dependent patent claims. The essence of the invention is as follows: A needle roller comprises - a hollow cylindrical support core with a longitudinal axis and a support core cylinder wall having an outer surface, and - a needle sleeve having a hollow cylindrical needle sleeve body and a plurality of outwardly projecting needle elements attached to the needle sleeve body, wherein the needle sleeve rests against the outer surface of the support core cylinder wall.The support core cylinder wall comprises a first axially extending base wall region and a second axially extending base wall region, each having a base wall thickness, as well as an axially extending recess region with a wall thickness reduced compared to the base wall thickness, wherein the recess region is arranged in the axial direction between the first base wall region and the second base wall region. Because the needle sleeve is arranged on the outer surface of the support core cylinder wall, adjacent to the support core, the support core supports and stabilizes the needle sleeve and, depending on the design, can also support the needle elements attached to the needle sleeve body from the inside out. In addition, the support core can be used to arrange the needle roller on a shaft.The base wall areas of the support core provide the necessary stability and rigidity to ensure the transmission of torque from the shaft to the support core and thus to the needle roller, as well as to attach the support core (and thus the needle roller) to the shaft. In the recess area, the support core primarily serves to support and stabilize the needle bushing (and possibly also the needle elements) from the inside. By designing the support core with a (one-piece) support core cylinder wall with different wall thicknesses in different areas of its axial length, a more optimal combination of stability and rigidity and low weight can be achieved than with a support core with a uniform wall thickness or a multi-part support core. The needle bushing body of the needle bushing is preferably made of one of the following materials: brass, bronze, steel, in particular stainless steel, aluminum or plastic, in particular polyoxymethylene.Accordingly, the hollow cylindrical support core can also be made of one of the following materials: steel, in particular stainless steel, aluminum, plastic, in particular polyoxymethylene, brass, or bronze. One advantage of the needle roller according to the invention is that, on the one hand, the support core in the base wall areas offers the necessary stability and strength to attach the support core to a shaft, and, on the other hand, due to the reduced wall thickness in the recess area compared to the base wall thickness, it has a significantly lower mass and weight compared to a needle roller without such a recess area. The reduced wall thickness in the recess area can, for example, correspond to less than half the base wall thickness over a large part of its axial length.The lower mass and weight are advantageous when transporting the needle rollers or the support cores alone, as support cores typically weigh several kilograms. The weight savings facilitate transport and save energy during transport. Furthermore, the lower mass also reduces the moment of inertia compared to a support core without a recess area. This means less torque is required to rotate the needle roller or to decelerate a rotating needle roller and bring it to a standstill. In designs in which the needle roller is driven by a motor, less powerful drives and brakes can be used to control the rotation of the needle roller.In designs in which the needle roller is driven by a film web, the film web to be perforated or fibrillated is protected due to the reduced moment of inertia of the needle roller. Preferably, the support core cylinder wall has an inner surface, wherein the inner surface in the recess area is offset radially outwards relative to the inner surface in the first and second base wall areas. This has the advantage that the reduction in the wall thickness of the support core cylinder wall can be achieved by modifying the support core wall on the inner surface. At the same time, a cylinder jacket-shaped outer surface can be retained without modifying the support core wall on its outer surface. In this way, the needle sleeve can be supported from the inside over the entire length of the support core and, at the same time, the wall thickness of the support core cylinder wall in the recess area can be reduced.In an advantageous embodiment, the recessed area extends in the axial direction over a length corresponding to at least one-third, in particular at least two-thirds, of the total length of the support core. This allows a significant reduction in the weight of the support core. Reducing the wall thickness by half results in a weight saving of approximately 1 / 6 if the recessed area extends in the axial direction over a length corresponding to one-third of the total length of the support core, and a reduction of approximately 1 / 3 if the recessed area extends over a length corresponding to two-thirds of the total length of the support core.The recess region preferably comprises a reinforcement region extending in the axial direction and having a reinforcement wall thickness which, compared to the wall thickness of partial regions of the recess region adjacent to the reinforcement region in the axial direction, is reduced to a lesser extent compared to the base wall thickness. This is advantageous in that the support core in the recess region is reinforced by the reinforcement region. Such a reinforcement region is particularly advantageous if it is arranged centrally in the recess region in the axial direction, since in this case the recess region is reinforced where the support core would otherwise be most susceptible to deformation, namely in the axial direction in the center of the recess region. In addition, a reinforcement region in the recess region allows the wall thickness in other parts of the recess region to be reduced more significantly, which in turn increases the overall weight savings.Advantageously, the support core cylinder wall has an end region extending in the axial direction towards a longitudinal end of the support core, in which end region the support core cylinder wall is shaped to widen conically on the inner surface towards the longitudinal end. This allows the support core to be fixed to the shaft by means of at least one driving ring with a wedge-shaped cross-sectional profile. Furthermore, an end region in which the support core cylinder wall is shaped to widen conically on the inner surface towards the longitudinal end offers production-related advantages. Furthermore, an end region shaped in this way results in additional weight savings compared to a support core cylinder wall with a cylindrical inner surface (i.e. not conical, with a constant wall thickness). In an advantageous embodiment, the support core cylinder wall is stepped in the axial direction on the inner surface at a transition from at least one of the base wall regions to the recess region."Stepped" here means that the support core cylinder wall is radially offset on the inner surface within a relatively short axial region, i.e., it has a step, in this case radially outward at a transition from one of the base wall regions to the recess region. This has the advantage that the wall thickness of the support core cylinder wall can be reduced uniformly over its entire length in the recess region. In this way, with a given minimum reduced wall thickness in the recess region, the weight reduction can be largely maximized.In an alternative advantageous embodiment, the support core cylinder wall has on the inner surface at a transition from at least one of the base wall regions to the recess region a transition region extending in the axial direction, in which the support core cylinder wall is shaped to widen conically on the inner surface from the base wall region in the axial direction towards the recess region. Such a support core is simple and cost-effective to produce. In addition, sharp edges on the inner surface of the support core cylinder wall are avoided, which could potentially be damaged and thus impair the service life of the support core. Advantageously, the hollow cylindrical support core rests with its inner surface on a shaft in the base wall regions of the support core cylinder wall. This is advantageous in that the support core in the regions of the support core cylinder wall with a greater wall thickness, i.e.in the areas of the support core cylinder wall with the highest stability, rests against the shaft. This minimizes the risk of deformation due to forces acting between the support core and the shaft. In an advantageous embodiment, the needle roller comprises at least one driver arranged in one of the base wall areas of the support core cylinder wall for transmitting torque from the shaft to the hollow cylindrical support core, wherein the at least one driver is preferably designed as a screw or key. This has the advantage that the torque is transmitted from the shaft to the support core in the base wall areas where the support core cylinder wall has the greatest wall thickness. Accordingly, the risk of damage to or deformation of the support core due to the torque acting between the shaft and the support core is also minimized.Furthermore, the base wall area, due to its relatively large base wall thickness, offers sufficient space for a sufficiently large driver. For example, a driver designed as a screw, in particular a grub screw, can be provided with a sufficiently long thread and thus firmly anchored in the support core cylinder wall. In a further advantageous embodiment, driver rings for transmitting torque from a shaft to the support core are arranged on the hollow cylindrical support core, in particular on both sides of the support core. In this way, the torque can be transmitted symmetrically and evenly with respect to the longitudinal axis from the shaft to the support core. This protects both the shaft and the support core. The invention is described in more detail below with reference to exemplary embodiments illustrated in the drawings. In the drawings: Fig.1 - a longitudinal section of a first embodiment of a needle roller according to the invention, which is arranged on a shaft; Fig. 2 - a side view of the first embodiment of the needle roller according to the invention, which is arranged on the shaft; Fig. 3 - a longitudinal section of a second embodiment of a needle roller according to the invention, which is arranged on a shaft; Fig. 4 - a side view of the second embodiment of the needle roller according to the invention, which is arranged on the shaft; Fig. 5 - a longitudinal section of a third embodiment of a needle roller according to the invention, which is arranged on a shaft; Fig. 6 - a side view of the third embodiment of the needle roller according to the invention, which is arranged on the shaft; Fig. 7 - a longitudinal section of a fourth embodiment of a support core of a needle roller according to the invention; Fig.Fig. 8 - a longitudinal section of a fifth embodiment of a support core with a reinforcement region of a needle roller according to the invention; Fig. 9 - a longitudinal section of a sixth embodiment of a support core of a needle roller according to the invention; Fig. 10 - a longitudinal section of a seventh embodiment of a support core of a needle roller according to the invention; and Fig. 11 - a longitudinal section of an eighth embodiment of a support core of a needle roller according to the invention. The following definition applies to the following description: If reference symbols are provided in a figure for the purpose of graphic clarity but are not mentioned in the directly associated description section, reference is made to their explanation in preceding or subsequent description sections. Conversely, to avoid graphic overload, reference symbols that are less relevant for immediate understanding are not shown in all figures.For this purpose, reference is made to the remaining figures. Fig. 1 shows a first embodiment of a needle roller 7 according to the invention, which is arranged on a shaft 6. The needle roller 7 has a hollow cylindrical support core 1 and a needle sleeve 2, which rests against an outer surface 18 of a support core cylinder wall 10 of the hollow cylindrical support core 1. The needle roller 7 was pressed firmly onto the outer surface 18 of the support core cylinder wall 10 of the support core 1 by hot pressing. The needle sleeve 2, made of brass, for example, has a hollow cylindrical needle sleeve body 21. A plurality of needle elements 20 are fastened to the needle sleeve body 21 and protrude outward from the needle sleeve body 21. In the present embodiment, only one needle sleeve 2 is arranged on the support core 1; in alternative embodiments, however, several needle sleeves can also be arranged on a support core.The hollow cylindrical support core 1, made of stainless steel for example, has a longitudinal axis 5 and the support core cylinder wall 10, which is rotationally symmetrical with respect to the longitudinal axis 5 and has the outer surface 18 and an inner surface 19. In the axial direction, i.e. in the direction of the longitudinal axis 5, the support core cylinder wall 10 has various regions which differ in the wall thickness of the support core cylinder wall 10. The support core cylinder wall 10 has a first base wall region 12a extending in the axial direction and a second base wall region 12b extending in the axial direction, in which the support core cylinder wall 10 has a base wall thickness W1. Furthermore, the support core cylinder wall 10 has a recess region 14 extending in the axial direction and having a wall thickness reduced compared to the base wall thickness W1.The recess region 14 extends over a length LA, which in the present exemplary embodiment corresponds to approximately two-thirds of a total length LG of the support core 1. The recess region 14 comprises a region 16 with a constant reduced wall thickness W2. In the present exemplary embodiment, the base wall thickness W1 is in a range from 3 mm to 8 mm, in particular 4 mm to 6 mm, and the reduced wall thickness W2 is in a range from 1 mm to 4 mm, in particular 2 mm to 3 mm. In the recess region 14, the inner surface 19 is offset radially outward compared to the two base wall regions 12a, 12b. The recess region 14 has, at a respective transition to the first base wall region 12a and to the second base wall region 12b, a first transition region 13a extending in the axial direction and a second transition region 13b extending in the axial direction.In the respective transition regions 13a, 13b, the support core cylinder wall 10 is shaped to widen conically on the inner surface 19 from the respective base wall region 12a, 12b to the recess region 14 or to the region 16 of constant, reduced wall thickness. Furthermore, the support core cylinder wall 10 comprises a first end region 11a extending in the axial direction, in which the support core cylinder wall 10 is shaped to widen conically on the inner surface 19 toward a first longitudinal end 31 of the support core 1. Accordingly, the support core 1 comprises a second end region 11b extending in the axial direction, in which the support core cylinder wall 10 is shaped to widen conically on the inner surface 19 toward a second longitudinal end 32 of the support core 1, opposite the first longitudinal end 31.The shaft 6, on which the needle roller 7 is arranged on an outer surface 60 of the shaft 6, is rotatable and can be driven by a drive motor or mounted for free rotation. The support core 1 rests in the two base wall areas 12a, 12b with the inner surface 19 against the outer surface 60 of the shaft 6. A first grub screw 41 is arranged in a corresponding threaded hole in the first base wall area 12a, and a second grub screw 42 is arranged in a corresponding threaded hole in the second base wall area 12b. The two grub screws 41, 42 fix the support core 1 to the shaft 6 and each serve as a driver for transmitting torque from the shaft 6 to the support core 1 and thus to the needle roller 7. Fig. 2 shows a side view of the first longitudinal end of the exemplary embodiment of the needle roller 7 arranged on the shaft 6, shown in longitudinal section in Fig. 1.Both the needle sleeve body 21 and the support core cylinder wall 10 are rotationally symmetrical with respect to the longitudinal axis 5. The needle elements 20 protrude radially outward from the needle sleeve body 21. The base wall thickness W1 and the reduced wall thickness W2 are each constant along the circumferential direction. Line II shows the section line of the longitudinal section of Fig. 1. Fig. 3 shows a second embodiment of a needle roller 107 according to the invention, which is arranged on a shaft 106. The needle roller 107 has a hollow cylindrical support core 101 and a needle sleeve 102, which rests against an outer surface 118 of a support core cylinder wall 110 of the hollow cylindrical support core 101. The needle roller 107 was pressed firmly onto the outer surface 118 of the support core cylinder wall 110 of the support core 101 by hot pressing. The needle sleeve 102, which is made of brass, for example, has a hollow cylindrical needle sleeve body 121.A plurality of needle elements 120 are attached to the needle sleeve body 121 and protrude outward from the needle sleeve body 121. The hollow cylindrical support core 101, made of stainless steel, for example, has a longitudinal axis 105 and a support core cylinder wall 110, which is rotationally symmetrical with respect to the longitudinal axis 105 and has an outer surface 118 and an inner surface 119. The support core cylinder wall 110 has a first base wall region 112a extending in the axial direction and a second base wall region 112b extending in the axial direction, in which the support core cylinder wall 110 has a base wall thickness W1. Furthermore, the support core cylinder wall 110 has a recess region 114 extending in the axial direction and having a wall thickness reduced compared to the base wall thickness W1. The recess region 114 extends over a length LA, which in the present embodiment corresponds to approximately two thirds of a total length LG of the support core 101.The recess region 114 comprises a region 116 with a constant reduced wall thickness W2. In the present exemplary embodiment, the base wall thickness W1 lies in a range from 3 mm to 8 mm, in particular 4 mm to 6 mm, and the reduced wall thickness W2 lies in a range from 1 mm to 4 mm, in particular 2 mm to 3 mm. In the recess region 114, the inner surface 119 is offset radially outward compared to the inner surface 119 in the two base wall regions 112a, 112b. The recess region 114 has, at a respective transition to the first base wall region 112a and to the second base wall region 112b, a first transition region 113a extending in the axial direction and a second transition region 113b extending in the axial direction.In the respective transition regions 113a, 113b, the inner surface 119 of the support core cylinder wall 110 is shaped to widen conically from the respective base wall region 112a, 112b to the recess region 114 or to the region 116 of constant, reduced wall thickness. Furthermore, the support core cylinder wall 110 comprises a first axially extending end region 111a, in which the support core cylinder wall 110 is shaped to widen conically on the inner surface 119 toward a first longitudinal end 131 of the support core 101. Accordingly, the support core 101 comprises a second axially extending end region 111b, in which the support core cylinder wall 110 is shaped to widen conically on the inner surface 119 toward a second longitudinal end 132 of the support core 101, opposite the first longitudinal end 131. The support core 101 is arranged on the shaft 106 by means of a first driving ring 141 and a second driving ring 142.The drive rings 141, 142 each have a wedge-shaped profile and rest against the inner surface 119 of the support core cylinder wall 110 in the first and second end regions 111a, 111b, respectively. The first and second drive rings 141, 142 are each secured by a first fastening ring 171 and a second fastening ring 173, which in turn are each secured to the shaft 106 by means of a grub screw 172, 174. The two fastening rings 171, 173 press the two drive rings 141, 142 against the inner surface 119 of the two end regions 111a, 111b of the support core cylinder wall 110. This ensures that the frictional forces between the driving rings 141, 142 and the inner surface 119 of the support core cylinder wall 110 are large enough to ensure a transmission of torque from the shaft 106 to the support core 101 and thus to the needle roller 107. Fig. 4 shows a side view of the first longitudinal end 131 of the support core shown in Fig.3 shows a longitudinal section of the embodiment of the needle roller 107 arranged on the shaft 106. Both the needle sleeve body 121 and the support core cylinder wall 110 are rotationally symmetrical with respect to the longitudinal axis 105. The needle elements 120 protrude radially outward from the needle sleeve body 121. The rotationally symmetrical fastening ring 171 can also be seen in side view. Line III-III shows the section line of the longitudinal section of Fig. 3. Fig. 5 shows a third embodiment of a needle roller 207 according to the invention, which is arranged on a shaft 206. The needle roller 207 has a hollow cylindrical support core 201 and a needle sleeve 202, which bears against an outer surface 218 of a support core cylinder wall 210 of the hollow cylindrical support core 201. The needle roller 207 was pressed onto the outer surface 218 of the support core cylinder wall 210 of the support core 201 by hot pressing.The needle sleeve 202, made of brass, for example, has a hollow cylindrical needle sleeve body 221. A plurality of needle elements 220 are attached to the needle sleeve body 221 and protrude outward from the needle sleeve body 221. The hollow cylindrical support core 201, made of stainless steel, for example, has a longitudinal axis 205 and a support core cylinder wall 210, which is rotationally symmetrical with respect to the longitudinal axis 205 and has an outer surface 218 and an inner surface 219. The support core cylinder wall 210 has a first axially extending base wall region 212a and a second axially extending base wall region 212b, in which the support core cylinder wall 210 has a base wall thickness W1. Furthermore, the support core cylinder wall 210 has a recess region 214 extending in the axial direction with a wall thickness reduced compared to the base wall thickness W1.The recess region 214 extends over a length LA, which in the present exemplary embodiment corresponds to approximately two-thirds of a total length LG of the support core 201. The recess region 214 comprises a region 216 with a constant reduced wall thickness W2. In the present exemplary embodiment, the base wall thickness W1 is in a range from 3 mm to 8 mm, in particular 4 mm to 6 mm, and the reduced wall thickness W2 is in a range from 1 mm to 4 mm, in particular 2 mm to 3 mm. In the recess region 214, the inner surface 219 is offset radially outward compared to the two base wall regions 212a, 212b. The recess region 214 has, at a respective transition to the first base wall region 212a and to the second base wall region 212b, a first transition region 213a extending in the axial direction and a second transition region 213b extending in the axial direction.In the respective transition regions 213a, 213b, the inner surface 219 of the support core cylinder wall 210 is shaped to widen conically from the respective base wall region 212a, 212b to the recess region 214 or to the region 216 of constant, reduced wall thickness. Furthermore, the support core cylinder wall 210 comprises a first axially extending end region 211a, in which the support core cylinder wall 210 is shaped to widen conically on the inner surface 219 toward a first longitudinal end 231 of the support core 201. Accordingly, the support core 201 comprises a second axially extending end region 211b, in which the support core cylinder wall 210 is shaped to widen conically on the inner surface 219 toward a second longitudinal end 232 of the support core 201, opposite the first longitudinal end 231.The torque is transmitted from the shaft 206 to the support core 201 and thus to the needle roller 207 by means of a key 241 arranged in a fitting groove 261 of the shaft 206. The key 241 contacts the inner surface 219 of the support core cylinder wall 210 in the first base wall region 212a in a partial circumferential direction. In the two base wall regions 212a, 212b, the support core 201 rests with its inner surface 219 against the outer surface 260 of the shaft 206, except in the partial region of the first base wall region 212a in which the key 241 contacts the inner surface 219 of the support core cylinder wall 210. The support core 201 is fastened to the shaft by means of a first fastening ring 271 and a second fastening ring 273.The first fastening ring 271 is fastened to the shaft 206 with a first grub screw 272 and the second fastening ring 273 is fastened to the shaft 206 with a second grub screw 274, thereby preventing movement of the support core 201 in the axial direction along the shaft 206. Fig. 6 shows a side view of the first longitudinal end 231 of the exemplary embodiment of the needle roller 207 arranged on the shaft 206, shown in longitudinal section in Fig. 5. Both the needle sleeve body 221 and the support core cylinder wall 210 are rotationally symmetrical with respect to the longitudinal axis 205. The needle elements 220 protrude radially outward from the needle sleeve body 221. The fastening ring 271, which is rotationally symmetrical with respect to the longitudinal axis 205, can also be seen in the side view. The line VV shows the section line of the longitudinal section of Fig. 5. Fig. 7 shows a fourth embodiment of a support core 301 for a needle roller according to the invention.The hollow cylindrical support core 301, made of stainless steel, for example, has a longitudinal axis 305 and a support core cylinder wall 310 that is rotationally symmetrical with respect to the longitudinal axis 305 and has an outer surface 318 and an inner surface 319. The support core cylinder wall 310 has a first base wall region 312a extending in the axial direction and a second base wall region 312b extending in the axial direction, in which the support core cylinder wall 310 has a base wall thickness W1. Furthermore, the support core cylinder wall 310 has an axially extending recess region 314 with a wall thickness reduced compared to the base wall thickness W1. The recess region 314 extends over a length LA, which in the present embodiment corresponds to approximately two-thirds of a total length LG of the support core 301.The recess region 314 has a reduced wall thickness W2 that is constant in the axial direction across the recess region 314. In the present exemplary embodiment, the base wall thickness W1 is in a range from 3 mm to 8 mm, in particular 4 mm to 6 mm, and the reduced wall thickness W2 is in a range from 1 mm to 4 mm, in particular 2 mm to 3 mm. In the recess region 314, the inner surface 319 is offset radially outward compared to the two base wall regions 312a, 312b. The support core cylinder wall 310 is stepped in the axial direction at a respective transition from the recess region 314 to the first base wall region 312a and to the second base wall region 312b on the inner surface 319, ie the support core cylinder wall 310 is offset in the radial direction on the inner surface 319 within a relatively short axial region in the axial direction (it has a step).Furthermore, the support core cylinder wall 310 comprises a first axially extending end region 311a, in which the support core cylinder wall 310 is shaped to widen conically on the inner surface 319 toward a first longitudinal end 331 of the support core 301. Accordingly, the support core 301 comprises a second axially extending end region 311b, in which the support core cylinder wall 310 is shaped to widen conically on the inner surface 319 toward a second longitudinal end 332 of the support core 301, opposite the first longitudinal end 331. Fig. 8 shows a fifth embodiment of a support core 401 for a needle roller according to the invention. The hollow cylindrical support core 401, which is made of stainless steel, for example, has a longitudinal axis 405 and a support core cylinder wall 410 that is rotationally symmetrical with respect to the longitudinal axis 405 and has an outer surface 418 and an inner surface 419.In the axial direction, the support core cylinder wall 410 has various regions that differ in wall thickness. The support core cylinder wall 410 has a first base wall region 412a extending in the axial direction and a second base wall region 412b extending in the axial direction, in which the support core cylinder wall 410 has a base wall thickness W1. Furthermore, the support core cylinder wall 410 has an axially extending recess region 414 with a wall thickness reduced compared to the base wall thickness W1. In the recess region 414, the inner surface 419 is offset radially outward compared to the two base wall regions 412a, 412b. The recess region 414 extends over a length LA, which in the present exemplary embodiment corresponds to approximately two-thirds of a total length LG of the support core 401.The recess region 414 comprises a first region 416a and a second region 416b of constant reduced wall thickness W2. In the present exemplary embodiment, the basic wall thickness W1 lies in a range from 3 mm to 8 mm, in particular 4 mm to 6 mm, and the reduced wall thickness W2 is in a range from 1 mm to 4 mm, in particular 2 mm to 3 mm. Between the two regions of constant wall thickness 416a, 416b there is arranged a reinforcement region 415 with a wall thickness W3 which, in comparison to the adjacent regions 416a, 416b of constant reduced wall thickness W2, is reduced to a lesser extent compared to the basic wall thickness W1, ie the wall thickness W3 lies between the basic wall thickness W1 and the reduced wall thickness W2. The support core cylinder wall 410 is stepped in the axial direction at a respective transition from the reinforcement region 415 to the two adjacent regions 416a, 416b of constant reduced wall thickness W2 on the inner surface 419.The recess region 414 has, at a respective transition to the first base wall region 412a and the second base wall region 412b, a first transition region 413a extending in the axial direction and a second transition region 413b extending in the axial direction. In the respective transition regions 413a, 413b, the inner surface 419 of the support core cylinder wall 410 is shaped to widen conically from the respective base wall region 412a, 412b to the recess region 414 or to the region 416a, 416b of constant reduced wall thickness. Furthermore, the support core cylinder wall 410 comprises a first end region 411a extending in the axial direction, in which the support core cylinder wall 410 is shaped to widen conically on the inner surface 419 toward a first longitudinal end 431 of the support core 401.Accordingly, the support core 401 comprises a second end region 411b extending in the axial direction, in which the support core cylinder wall 410 is shaped to widen conically at the inner surface 419 toward a second longitudinal end 432 of the support core 401, opposite the first longitudinal end 431. Fig. 9 shows a sixth embodiment of a support core 501 for a needle roller according to the invention. The hollow cylindrical support core 501, made of stainless steel, for example, has a longitudinal axis 505 and a support core cylinder wall 510 that is rotationally symmetrical with respect to the longitudinal axis 505 and has an outer surface 518 and an inner surface 519. The support core cylinder wall 510 has a first axially extending base wall region 512a and a second axially extending base wall region 512b, in which the support core cylinder wall 510 has a base wall thickness W1.Furthermore, the support core cylinder wall 510 has a recess region 514 extending in the axial direction with a wall thickness reduced compared to the base wall thickness W1. In the recess region 514, the inner surface 519 is offset radially outward compared to the two base wall regions 512a, 512b. The recess region 514 extends over a length LA, which in the present embodiment corresponds to approximately two-thirds of a total length LG of the support core 501. The recess region 514 comprises a region 516 with a constant reduced wall thickness W2. In the present embodiment, the base wall thickness W1 is in a range from 3 mm to 8 mm, in particular 4 mm to 6 mm, and the reduced wall thickness W2 is in a range from 1 mm to 4 mm, in particular 2 mm to 3 mm.The recess region 514 has, at a respective transition to the first base wall region 512a and the second base wall region 512b, a first transition region 513a extending in the axial direction and a second transition region 513b extending in the axial direction. In the respective transition regions 513a, 513b, the inner surface 519 of the support core cylinder wall 510 is shaped to widen conically from the respective base wall region 512a, 512b to the recess region 514 or to the region 516 of constant reduced wall thickness. In contrast to the preceding exemplary embodiments, the base wall regions 512a, 512b extend to the respective longitudinal end 531, 532 of the support core 501 and thus have no end regions in which the inner surface of the support core cylinder wall is conically shaped. Fig. 10 shows a seventh embodiment of a support core 601 for a needle roller according to the invention.The hollow cylindrical support core 601, made of stainless steel, for example, has a longitudinal axis 605 and a support core cylinder wall 610 that is rotationally symmetrical with respect to the longitudinal axis 605 and has an outer surface 618 and an inner surface 619. In the axial direction, the support core cylinder wall 610 has various regions that differ in the wall thickness of the support core cylinder wall 610. The support core cylinder wall 610 has a first base wall region 612a extending in the axial direction and a second base wall region 612b extending in the axial direction, in which the support core cylinder wall 610 has a base wall thickness W1. Furthermore, the support core cylinder wall 610 has a recess region 614 extending in the axial direction with a wall thickness reduced compared to the base wall thickness W1. In the recess area 614, the inner surface 619 is offset radially outwards compared to the two base wall areas 612a, 612b.The recess region 614 extends over a length LA, which in the present exemplary embodiment corresponds to approximately two-thirds of a total length LG of the support core 601. The recess region 614 has a reduced wall thickness W2 that remains constant in the axial direction across the recess region 614. In the present exemplary embodiment, the base wall thickness W1 is in a range from 3 mm to 8 mm, in particular 4 mm to 6 mm, and the reduced wall thickness W2 is in a range from 1 mm to 4 mm, in particular 2 mm to 3 mm. The support core cylinder wall 610 is stepped in the axial direction at a respective transition from the recess region 614 to the first base wall region 612a and to the second base wall region 612b on the inner surface 619, ie the support core cylinder wall 610 is offset in the radial direction on the inner surface 619 within a relatively short axial region in the axial direction (it has a step).The base wall regions 612a, 612b each extend to the respective longitudinal end 631, 632 of the support core 601 and thus have no end regions in which the inner surface of the support core cylinder wall is conically shaped. Fig. 11 shows an eighth embodiment of a support core 801 for a needle roller according to the invention. The hollow cylindrical support core 701, made of stainless steel, for example, has a longitudinal axis 705 and a support core cylinder wall 710 that is rotationally symmetrical with respect to the longitudinal axis 705 and has an outer surface 718 and an inner surface 719. The support core cylinder wall 710 has a first base wall region 712a extending in the axial direction and a second base wall region 712b extending in the axial direction, in which the support core cylinder wall 710 has a base wall thickness W1.Furthermore, the support core cylinder wall 710 has a recess region 714 extending in the axial direction with a wall thickness reduced compared to the base wall thickness W1. In the recess region 714, the inner surface 719 is offset radially outward compared to the two base wall regions 712a, 712b. The recess region 714 extends over a length LA, which in the present embodiment corresponds to approximately two-thirds of a total length LG of the support core 701. The recess region 714 comprises a first region 716a and a second region 716b of constant reduced wall thickness W2. In the present embodiment, the base wall thickness W1 is in a range from 3 mm to 8 mm, in particular 4 mm to 6 mm, and the reduced wall thickness W2 is in a range from 1 mm to 4 mm, in particular 2 mm to 3 mm.Between the two regions of constant wall thickness 716a, 716b there is arranged a reinforcement region 715 with a wall thickness W3 which, in comparison to the adjacent regions 716a, 716b of constant reduced wall thickness W2, is reduced to a lesser extent compared to the basic wall thickness W1, i.e. the wall thickness W3 lies between the basic wall thickness W1 and the reduced wall thickness W2. The support core cylinder wall 710 is stepped in the axial direction at a respective transition from the reinforcement region 715 to the two adjacent regions 716a, 716b of constant reduced wall thickness W2 on the inner surface 719, i.e. the support core cylinder wall 710 is offset in the radial direction on the inner surface 719 within a relatively short axial region in the axial direction (it has a step).The recess region 714 has, at a respective transition to the first base wall region 712a and the second base wall region 712b, a first transition region 713a extending in the axial direction and a second transition region 713b extending in the axial direction. In the respective transition regions 713a, 713b, the inner surface 719 of the support core cylinder wall 710 is shaped to widen conically from the respective base wall region 712a, 712b to the recess region 714 or to the region 716a, 716b of constant reduced wall thickness. The base wall regions 712a, 712b each extend to the respective longitudinal end 731, 732 of the support core 701 and thus have no end regions in which the inner surface of the support core cylinder wall is conically shaped.

Claims

Patent claims 1. Needle roller (7; 107; 207), comprising: - a hollow cylindrical support core (1; 101; 201; 301; 401; 501; 601; 701) with a longitudinal axis (5; 105; 205; 305; 405; 505; 605; 705) and a support core cylinder wall (10; 110; 210; 310; 410; 510; 610; 710) having an outer surface (18; 118; 218; 318; 418; 518; 618; 718), and - a needle sleeve (2; 102; 202) which has a hollow cylindrical needle sleeve body (21; 121; 221) and a plurality of outwardly projecting needle elements (20; 120; 220) fastened to the needle sleeve body, wherein the needle sleeve rests against the outer surface of the support core cylinder wall, characterized in that the support core cylinder wall has a first base wall region (12a; 112a; 212a; 312a; 412a; 512a; 612a; 712a) extending in the axial direction and a second base wall region (12b; 112b; 212b; 312b; 412b; 512b; 612b;712b), each having a base wall thickness (W1), and a recess region (14; 114; 214; 314; 414; 514; 614; 714) extending in the axial direction and having a wall thickness (W2) reduced compared to the base wall thickness (W1), wherein the recess region is arranged in the axial direction between the first base wall region and the second base wall region.

2. Needle roller (7; 107; 207) according to claim 1, characterized in that the support core cylinder wall (10; 110; 210; 310; 410; 510; 610; 710) has an inner surface (19; 119; 219; 319; 419; 519; 619; 719), wherein the inner surface in the recess region (14; 114; 214; 314; 414; 514; 614; 714) relative to the inner surface in the first and second base wall region (12a, 12b; 112a, 112b; 212a, 212b; 312a, 312b; 412a, 412b; 512a, 512b; 612a, 612b; 712a, 712b) is offset radially outwards.

3. Needle roller (7; 107;207) according to one of the preceding claims, characterized in that the recess region (14; 114; 214; 314; 414; 514; 614; 714) extends in the axial direction over a length (LA) which is at least; one-third, in particular at least two-thirds, of a total length (LG) of the support core.

4. Needle roller (7; 107; 207) according to one of the preceding claims, characterized in that the recess region (414; 714) comprises a reinforcement region (415; 715) extending in the axial direction and having a reinforcement wall thickness (W3) that is reduced to a lesser extent compared to the base wall thickness (W1) compared to the wall thickness of partial regions (416a, 416b; 716a, 716b) of the recess region that are adjacent to the reinforcement region (415; 715) in the axial direction.Needle roller (7; 107; 207) according to one of the preceding claims, characterized in that the support core cylinder wall (10; 110; 210; 310; 410) has an end region (11a, 11b; 111a, 111b; 211a, 211b; 311a, 311b; 411a, 411b) extending in the axial direction towards a longitudinal end (31, 32; 131, 132; 231, 232; 331, 332; 431, 432; 531, 532; 631, 632; 731, 732) of the support core, in which end region the support core cylinder wall on the inner surface (19; 119; 219; 319; 419) is shaped to widen conically toward the longitudinal end.

6. Needle roller (7; 107; 207) according to one of claims 2 to 5, characterized in that the support core cylinder wall (310; 610) is stepped in the axial direction on the inner surface (319; 619) at a transition from at least one of the base wall regions (312a, 312b; 612a, 612b) to the recess region (314; 614).Needle roller (7; 107; 207) according to one of claims 2 to 6, characterized in that the support core cylinder wall (10; 110; 210; 410; 510; 710) on the inner surface (19; 119; 219; 419; 519; 719) at a transition from at least one of the base wall regions (12a, 12b; 112a, 112b; 212a, 212b; 412a, 412b; 512a, 512b; 712a, 712b) to the recess region (14; 114; 214; 414; 514; 714) has a transition region (13a, 13b; 113a; 113b; 213a; 213b; 413a, 413b; 513a, 513b; 713a, 713b), in which the support core cylinder wall is shaped to widen conically on the inner surface from the base wall region in the axial direction (5; 105; 205; 405; 505; 705) towards the recess region.

8. Needle roller (7; 207) according to one of claims 2 to 7, characterized in that the hollow cylindrical support core (1; 201) bears against a shaft (6, 206) with the inner surface (19; 219) in the base wall regions (12a, 12b; 212a, 212b) of the support core cylinder wall (10; 210).

9. Needle roller (7; 207) according to claim 8, characterized in that it comprises at least one driver arranged in one of the base wall regions (12a, 12b; 212a, 212b) of the support core cylinder wall (10; 210) for transmitting torque from the shaft (6; 206) to the hollow cylindrical support core (1; 201), wherein the at least one driver is preferably designed as a screw (41, 42) or key (241).

10. Needle roller (107) according to one of claims 1 to 7, characterized in that driver rings (141, 142) for transmitting torque from a shaft (106) to the support core are arranged on the hollow cylindrical support core (101).

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