Drive device for a forklift truck and forklift truck

Abstract

A drive device (1) for a forklift truck is shown and described, wherein the drive device (1) has a shaft section (21) and a hub section (19), wherein the shaft section (21) has a polygonal outer surface (25) and the hub section (19) has a polygonal inner surface (23), and wherein the polygonal outer surface (25) and the polygonal inner surface (23) are designed such that when the shaft section (21) and the hub section (19) are arranged relative to each other such that the outer surface (25) and the inner surface (23) face each other, the outer surface (25) and the inner surface (23) form a positive-locking connection between the shaft section (21) and the hub section (19). A forklift truck with a drive device (1) is also described.

Description

[0001] The present invention relates to a drive device for a forklift truck and a forklift truck. Drive devices for forklift trucks are known from the prior art. In general, it is desirable for drive devices for forklift trucks to be mechanically robust, to require little installation space, and to be easy to install.

[0002] The object of the present invention is therefore to provide a mechanically robust drive device that requires little installation space and is easy to assemble.

[0003] According to a first aspect of the invention, the aforementioned problem is solved by a drive device with the features of claim 1. The drive device is configured for a forklift truck. The drive device comprises a shaft section and a hub section. The shaft section has a polygonal outer surface, and the hub section has a polygonal inner surface. The polygonal outer surface and the polygonal inner surface are designed such that when the shaft section and the hub section are arranged relative to each other such that the outer surface and the inner surface face each other, the outer surface and the inner surface form a positive-locking connection between the shaft section and the hub section.

[0004] As previously described, the drive device is configured for a forklift truck. Preferably, the drive device has a mounting section with which it can be attached to a mounting section of the forklift truck.

[0005] As previously described, the drive device comprises a shaft section and a hub section. Preferably, the shaft section is a section of a shaft, more preferably a wheel shaft, a bevel gear shaft, or an output shaft. More preferably, the shaft section is a section of a planet carrier or an axle carrier. Preferably, the hub section is a section of a bevel gear.

[0006] Alternatively, preferably, the hub section is a section of a wheel shaft. Alternatively, preferably, the hub section is a section of a spur gear. Alternatively, preferably, the hub section is a section of a drive pinion.

[0007] As previously described, the shaft section has a polygonal outer surface, and the hub section has a polygonal inner surface. A polygonal connection between the shaft section and the hub section can be provided using the polygonal outer and inner surfaces. Preferably, both the inner and outer surfaces are defined by a uniform thickness. Preferably, the inner and outer surfaces are designed according to DIN 32711, in particular DIN 32711-1, or DIN 32712.

[0008] As previously described, the polygonal outer surface and the polygonal inner surface are designed such that when the shaft section and the hub section are arranged relative to each other in such a way that the outer and inner surfaces face each other, the outer and inner surfaces form a positive-locking connection between the shaft section and the hub section. When the shaft section and the hub section are arranged relative to each other in such a way that the outer and inner surfaces face each other and form a positive-locking connection between the shaft section and the hub section, the shaft section and the hub section are in a connected state. Preferably, the shaft section and the hub section are in this connected state.Because the polygonal outer surface and the polygonal inner surface form a positive-locking connection between the shaft section and the hub section, it is ensured that a positive-locking polygon connection is provided by means of the inner and outer surfaces, through which torques can be transmitted between the shaft section and the hub section, transverse forces acting perpendicular to an extension direction of the shaft section can be transmitted between the shaft section and the hub section, bending moments can be transmitted between the shaft section and the hub section, and in addition, the shaft section and the hub section can be centered relative to each other, thus ensuring smooth running.Furthermore, the fact that the polygonal outer and inner surfaces form a positive-locking connection between the shaft section and the hub section ensures that the drive device can be designed to be particularly space-saving and easy to assemble; that is, the shaft section and the hub section can be easily brought into the connected state. Overall, this results in a mechanically robust, compact, and easy-to-assemble drive device.

[0009] In summary, it can be stated that the present invention provides a mechanically robust drive device that requires little installation space and is easy to assemble.

[0010] In one embodiment, the positive-locking connection between the shaft section and the hub section is designed such that the shaft section and the hub section are displaceable relative to each other along one direction of extension of the shaft section. By designing the positive-locking connection between the shaft section and the hub section in such a way that the shaft section and the hub section are displaceable relative to each other along the direction of extension of the shaft section, it is ensured that when adjusting a bearing preload of one or more bearings, wherein either the shaft section or the hub section is rotatably mounted relative to a housing of the drive device with respect to the bearing or each bearing, the shaft section and the hub section can be displaced relative to each other.Furthermore, by designing the positive-locking connection between the shaft section and the hub section in such a way that the shaft section and the hub section are displaceable relative to each other along the extension direction of the shaft section, it can be ensured that the shaft section and the hub section can be brought into the connected state particularly easily.

[0011] In one embodiment, the positive-locking connection between the shaft section and the hub section is designed such that the shaft section and the hub section are frictionally connected along the direction of extension of the shaft section. By designing the positive-locking connection between the shaft section and the hub section in such a way that the shaft section and the hub section are frictionally connected along the direction of extension of the shaft section, it is ensured that axial forces acting along the direction of extension of the shaft section can be at least partially transmitted between the shaft section and the hub section, so that, in particular, any further components of the drive device that may be included need to be less mechanically robust.

[0012] In one embodiment, the shaft section and the hub section are secured against displacement relative to each other along their direction of extension. Particularly when the positive-locking connection between the shaft section and the hub section is designed such that the shaft section and the hub section are displaceable relative to each other along one direction of extension, the shaft section and the hub section can be secured against displacement relative to each other along their direction of extension by means of a further component or components of the drive device. Preferably, the shaft section and the hub section are secured against displacement relative to each other along their direction of extension by means of a locking element.

[0013] In one embodiment, the shaft section and the hub section are secured against displacement relative to each other along their direction of extension by means of one or more nuts. Preferably, the nut or each nut forms a locking element. Preferably, a bearing preload of one or more bearings can be set by means of the tightening torque of the nut or each nut, wherein either the shaft section or the hub section is rotatably mounted relative to the housing of the drive device by means of the bearing or each bearing. By securing the shaft section and the hub section against displacement relative to each other along their direction of extension by means of one or more nuts, a particularly simple locking element is provided.Preferably, the nut or each nut is placed on a thread of either the shaft section or the hub section.

[0014] In one embodiment, the shaft section and the hub section are secured against displacement relative to each other along their direction of travel by means of a shaft shoulder. Preferably, either the shaft section or the hub section has the shaft shoulder. Preferably, the shaft shoulder has a contact surface against which either a contact surface of the shaft section or a contact surface of the hub section rests. By securing the shaft section and the hub section against displacement relative to each other along their direction of travel by means of a shaft shoulder, a particularly simple locking element is provided.

[0015] In one embodiment, the shaft section and the hub section are secured against displacement relative to each other along their direction of travel by means of a retaining ring. Preferably, the retaining ring is arranged section by section in a groove of the shaft section or in a groove of the hub section. By arranging the retaining ring section by section in a groove of the shaft section or in a groove of the hub section, the retaining ring is secured against slippage relative to the shaft section or relative to the hub section. Securing the shaft section and the hub section against displacement relative to each other along their direction of travel by means of a retaining ring ensures that a particularly simple locking element is provided.

[0016] In one embodiment, the shaft section and the hub section are mechanically preloaded relative to each other along the direction of extension of the shaft section. This mechanical preloading ensures a frictional connection between the shaft section and the hub section, resulting in a particularly robust mechanical link.

[0017] In one embodiment, the drive device comprises a machine unit, a gear unit with a first section that can be set into rotary motion by means of the machine unit, and a second section that can be set into rotary motion by the rotary motion of the first section via one or more gear stages, and a mounting section that is rotationally fixed to the second section of the gear unit. Preferably, the machine unit comprises the shaft section and the first section of the gear unit comprises the hub section. Alternatively, preferably, the machine unit comprises the hub section and the first section of the gear unit comprises the shaft section. Preferably, the gear unit comprises both the shaft section and the hub section.Preferably, a first gear stage of the gear unit comprises the shaft section and a second gear stage of the gear unit comprises the hub section, wherein, in the direction of force flow from the machine unit towards the mounting section, the first gear stage is arranged first and then the second gear stage. Alternatively, preferably, a first gear stage of the gear unit comprises the hub section and a second gear stage of the gear unit comprises the shaft section, wherein, in the direction of force flow from the machine unit towards the mounting section, the first gear stage is arranged first and then the second gear stage. Preferably, the second section of the gear unit comprises the shaft section and the mounting section comprises the hub section.Alternatively, preferably, the second section of the transmission unit comprises the hub section and the mounting section comprises the shaft section. Preferably, a vehicle wheel can be attached to the mounting section. Preferably, the machine unit is an electric machine unit. Alternatively, preferably, the machine unit is a hydraulic machine unit.

[0018] According to a second aspect of the invention, the aforementioned problem is solved by a forklift truck with the features of claim 10. The forklift truck has a drive device according to the first aspect. The features, technical effects, and / or advantages described in connection with the drive device according to the first aspect of the invention also apply, at least analogously, to the forklift truck according to the second aspect of the invention, so that a corresponding repetition is omitted here. The forklift truck can also be referred to as a material handling vehicle. Preferably, the forklift truck is a forklift, in particular a counterbalance forklift.

[0019] In particular, the drive device according to the invention is advantageous compared to drive devices that use a splined shaft connection, such as according to DIN 5480, instead of a polygon connection, since very high torques, as well as bending moments and transverse forces, can be transmitted with the help of the polygon connection between the shaft section and the hub section. In particular, the drive device according to the invention is advantageous compared to drive devices that use a splined shaft connection, such as according to DIN 5480, instead of a polygon connection, because the polygon connection centers the shaft section and the hub section relative to each other, whereby an additional cylindrical seat to fulfill a centering function is possible, but not necessary.In particular, the drive device according to the invention is advantageous compared to drive devices that use a splined shaft connection, such as according to DIN 5480, instead of a polygon connection, because with the polygon connection, no separate operation, such as profile milling, is necessary when manufacturing the polygon profile of the shaft section, since circular cross-sections and a polygon profile can be machined in a single operation. Preferably, no tool runout in the axial direction is required when machining the shaft section, which enables optimal utilization of the installation space. In particular, the drive device according to the invention is also advantageous compared to drive devices that use a tapered press fit instead of a polygon connection, since the polygon connection can be assembled and disassembled without special tools or a press.In particular, the drive device according to the invention is also advantageous compared to drive devices in which no shaft-hub connection is provided in certain sections, since in the drive device according to the invention a simpler design and manufacture of the component that has the shaft section and the component that has the hub section is possible and in particular large shaft seals can also be dispensed with.

[0020] Further features, advantages, and applications of the present invention will become apparent from the following description of the exemplary embodiments and the figures. All features described and / or illustrated, individually and in any combination, constitute the subject matter of the invention, irrespective of their composition in the individual claims or their cross-references. In the figures, the same reference numerals denote identical or similar objects. Fig. Figures 1 to 3 show schematic representations of a first embodiment of a drive device according to the invention. Fig. 4 and Fig. 5 show schematic representations of a second embodiment of the drive device according to the invention, Fig. 6 and Fig. Figure 7 shows schematic representations of a third embodiment of the drive device according to the invention. Fig. 8 and Fig. Figure 9 shows schematic representations of a fourth embodiment of the drive device according to the invention, and Fig. 10 and Fig. Figure 11 shows schematic representations of a fifth embodiment of the drive device according to the invention.

[0021] Fig. Figures 1 to 3 show schematic representations of a first embodiment of a drive device 1 according to the invention. Fig. 4 and Fig. Figure 5 shows schematic representations of a second embodiment of the drive device 1 according to the invention. Fig. 6 and Fig. Figure 7 shows schematic representations of a third embodiment of the drive device 1 according to the invention. Fig. 8 and Fig. Figure 9 shows schematic representations of a fourth embodiment of the drive device 1 according to the invention, and Fig. 10 and Fig. Figure 11 shows schematic representations of a fifth embodiment of the drive device 1 according to the invention.

[0022] The drive device 1 is configured for a forklift truck (not shown) and has a mounting section with which the drive device 1 can be attached to a mounting section of the forklift truck.

[0023] The in the Fig. Figures 1 to 3 schematically illustrate the first embodiment of the drive device 1 according to the invention, which comprises a gear unit 3, also known as a spur gear-bevel gear unit. This first embodiment of the drive device 1 according to the invention can be used as a drive system for a forklift or industrial truck. The gear unit 3 has a spur gear stage 5, which can also be referred to as the first gear stage. The spur gear stage 5 comprises a drive pinion 7 and a spur gear 9. The drive pinion 7 is driven by a machine unit of the drive device 1 (not shown), which in the illustrated embodiment is an electric machine and provides the drive power in the form of torque and rotational speed. The drive pinion 7 can also be referred to as the first section of the gear unit 3, which can be set into rotary motion by means of the machine unit.The drive pinion 7 and the spur gear 9 are operatively connected via their teeth, so that the drive power is transmitted from the drive pinion 7 to the spur gear 9. In addition to the spur gear stage 5, the gear unit 3 has a bevel gear stage 11, which can also be referred to as the second gear stage. The bevel gear stage 11 has a bevel gear shaft 13 and a bevel gear 15. The spur gear 9 and the bevel gear shaft 13 are rigidly connected to each other by means of a shaft-hub connection, so that the drive power is transmitted from the spur gear stage 5 to the bevel gear stage 11. The bevel gear shaft 13 and the bevel gear 15 are operatively connected via their teeth, so that the drive power is transmitted from the bevel gear shaft 13 to the bevel gear 15. The bevel gear 15 can also be referred to as the second section of the gear unit 3, which can be set into rotation by the rotational movement of the first section via one or more gear stages.Furthermore, the drive device 1 has a wheel shaft 17. The bevel gear 15 has a hub section 19, and the wheel shaft 17 has a shaft section 21. The drive device 1 thus has the hub section 19 and the shaft section 21. The hub section 19 has a polygonal inner surface 23, and the shaft section 21 has a polygonal outer surface 25. The polygonal outer surface 25 and the polygonal inner surface 23 are designed such that when the shaft section 21 and the hub section 19 are arranged relative to each other such that the outer surface 25 and the inner surface 23 face each other, the outer surface 25 and the inner surface 23 form a positive-locking connection between the shaft section 21 and the hub section 19.Then, when the shaft section 21 and the hub section 19 are arranged relative to each other such that the outer surface 25 and the inner surface 23 face each other and the outer surface 25 and the inner surface 23 form a positive-locking connection between the shaft section 21 and the hub section 19, the shaft section 21 and the hub section 19 are in a connected state. Preferably, the shaft section 21 and the hub section 19 are in the connected state.The fact that the polygonal outer surface 25 and the polygonal inner surface 23 form a positive-locking connection between the shaft section 21 and the hub section 19 ensures that a positive-locking polygon connection is provided by means of the inner surface 23 and the outer surface 25, through which torques can be transmitted between the shaft section 21 and the hub section 19, transverse forces acting perpendicular to a direction of extension of the shaft section 21 can be transmitted between the shaft section 21 and the hub section 19, bending moments can be transmitted between the shaft section 21 and the hub section 19, and in addition, the shaft section 21 and the hub section 19 can be centered relative to each other, thus ensuring smooth running.Furthermore, the fact that the polygonal outer surface 25 and the polygonal inner surface 23 form a positive-locking connection between the shaft section 21 and the hub section 19 ensures that the drive device 1 can be designed to be particularly space-saving and easy to assemble; that is, the shaft section 21 and the hub section 19 can be easily brought into the connected state. Overall, a mechanically robust, space-saving, and easy-to-assemble drive device 1 can thus be provided. In the connected state, the bevel gear 15 and the wheel shaft 17 are arranged concentrically with respect to the teeth of the bevel gear 15. In other words, the bevel gear 15 has a polygonal hub profile aligned concentrically with the teeth of the bevel gear 15, and the wheel shaft 17 has a polygonal shaft profile.

[0024] The inner surface 23 and the outer surface 25 are in the Fig. Figures 1 to 3 schematically illustrate the first embodiment of the drive device 1 according to the invention, as defined in DIN 32711-1. Both the inner surface 23 and the outer surface 25 are each defined by a uniform thickness. Fig. Figure 3 also shows diameters d1, d2, d3, d4, d5, and d6, as well as eccentrics e1 and e2. Each constant thickness is defined by d1 or d4. The diameters d1 and d4, d2 and d5, and d3 and d6 correspond to each other. Likewise, the eccentrics e1 and e2 correspond to each other. Using the eccentrics e1 and e2, a positive-locking shaft-hub connection is created, capable of transmitting torques, bending moments, and shear forces.

[0025] The positive-locking connection between shaft section 21 and hub section 19 is designed such that shaft section 21 and hub section 19 are displaceable relative to each other along one direction of extension of shaft section 21. The bevel gear 15, which can also be referred to as a ring gear, is displaceable on the gear shaft 17 in the axial direction, i.e., along the direction of extension of shaft section 21. Fig. Figure 1 shows a rotation axis 27, along which the direction of extension of the shaft section 21 runs in the assembled state. In the Fig. In the schematically illustrated first embodiment of the drive device 1 according to the invention, a clearance fit, namely H7 / g6, is provided, such that the shaft section 21 and the hub section 19 can be displaced relative to each other without noticeable play along the direction of extension of the shaft section 21. In an alternative embodiment of the drive device 1 according to the invention, which is not shown, a transition fit, namely H7 / k6, is provided. In a further alternative embodiment of the drive device 1 according to the invention, which is also not shown, an interference fit is provided, which can also be referred to as an interference fit. Axial forces can be transmitted between the hub section 19 and the shaft section 21 by means of the interference fit.In this embodiment, the positive-locking connection between the shaft section 21 and the hub section 19 is designed such that the shaft section 21 and the hub section 19 are frictionally connected to each other along the direction of extension of the shaft section 21. Because the positive-locking connection between the shaft section 21 and the hub section 19 is designed such that the shaft section 21 and the hub section 19 are frictionally connected to each other along the direction of extension of the shaft section 21, it is ensured that axial forces acting along the direction of extension of the shaft section 21 between the shaft section 21 and the hub section 19 can be transmitted at least partially, so that, in particular, any further components of the drive device 1 that may be provided need to be less mechanically robust.

[0026] The in the Fig. The schematically depicted first embodiment of the drive device 1 according to the invention, shown in Figures 1 to 3, also includes a first tapered roller bearing 29, a second tapered roller bearing 31, a first nut 33, and a second nut 35. The first nut 33 and the second nut 35 can each also be referred to as further components of the drive device 1. A bearing preload of both the first tapered roller bearing 29 and the second tapered roller bearing 31 can be set by means of the tightening torque of the first nut 33.In particular, because the positive-locking connection between the shaft section 21 and the hub section 19 is designed such that the shaft section 21 and the hub section 19 are displaceable relative to each other along the direction of extension of the shaft section 21, the bearing preload of both the first tapered roller bearing 29 and the second tapered roller bearing 31 can be adjusted using the tightening torque of the first nut 33. For this purpose, the first nut 33 is placed on a thread of the shaft section 21 and screwed onto the thread in the direction of a mounting section 37 of the wheel shaft 17, to which a vehicle wheel can be attached. The mounting section 37 is rotationally fixed to the second section of the gear unit 3, which in this example is the bevel gear 15.Furthermore, a first section of an inner ring of the first tapered roller bearing 29 rests against a contact surface of the hub section 19 pointing in a first direction 39, which runs along the extension direction of the shaft section 21, and a second section of an outer ring of the first tapered roller bearing 29 rests against a contact surface of a housing 43 of the drive device 1 pointing in a second direction 41 opposite to the first direction 39. Additionally, a first section of an inner ring of the second tapered roller bearing 31 rests against a contact surface of the shaft section 21 pointing in the second direction 41, and a second section of an outer ring of the second tapered roller bearing 31 rests against a contact surface of the housing 43 of the drive device 1 pointing in the first direction 39.After adjusting the bearing preload of the first tapered roller bearing 29 and the second tapered roller bearing 31, the second nut 35 is tightened against the first nut 33. This securely clamps both the first nut 33 and the second nut 35 onto a threaded stud 45 of the wheel shaft 17, which provides the thread. This allows axial forces to be transmitted from the wheel shaft 17 or the bevel gear 15 to the first tapered roller bearing 29 and the second tapered roller bearing 31, and thus to the housing 43, which can also be referred to as the gearbox housing. The shaft section 21 and the hub section 19 are therefore secured against displacement relative to each other along their direction of travel. Specifically, the shaft section 21 and the hub section 19 are secured against displacement relative to each other along their direction of travel by means of the first nut 33 and the second nut 35.

[0027] The in the Fig. 4 and Fig. Figure 5, a schematic representation of the second embodiment of the drive device 1 according to the invention, has a gear unit 3, which can also be referred to as a spur gear-planetary gear unit. The second embodiment of the drive device 1 according to the invention can be used as a drive system for a forklift or industrial truck. The drive device 1 has a machine unit 47, which in the second embodiment is an electric machine. The gear unit 3 has a planetary stage 49, which transmits torque to a wheel shaft 17 by means of a planet carrier 51 of the planetary stage 49. The planet carrier 51 can also be referred to as the second section of the gear unit 3, which can be set into rotary motion by the rotary motion of a first section via one or more gear stages. The wheel shaft 17 has a hub section 19, and the planet carrier 51 has a shaft section 21.The drive device 1 thus comprises the hub section 19 and the shaft section 21. The hub section 19 has a polygonal inner surface 23 and the shaft section 21 has a polygonal outer surface 25. The polygonal outer surface 25 and the polygonal inner surface 23 are designed such that when the shaft section 21 and the hub section 19 are arranged relative to each other such that the outer surface 25 and the inner surface 23 face each other, the outer surface 25 and the inner surface 23 form a positive-locking connection between the shaft section 21 and the hub section 19.Then, when the shaft section 21 and the hub section 19 are arranged relative to each other such that the outer surface 25 and the inner surface 23 face each other and the outer surface 25 and the inner surface 23 form a positive-locking connection between the shaft section 21 and the hub section 19, the shaft section 21 and the hub section 19 are in a connected state. Preferably, the shaft section 21 and the hub section 19 are in the connected state.The fact that the polygonal outer surface 25 and the polygonal inner surface 23 form a positive-locking connection between the shaft section 21 and the hub section 19 ensures that a positive-locking polygon connection is provided by means of the inner surface 23 and the outer surface 25, through which torques can be transmitted between the shaft section 21 and the hub section 19, transverse forces acting perpendicular to a direction of extension of the shaft section 21 can be transmitted between the shaft section 21 and the hub section 19, bending moments can be transmitted between the shaft section 21 and the hub section 19, and in addition, the shaft section 21 and the hub section 19 can be centered relative to each other, thus ensuring smooth running.Furthermore, the fact that the polygonal outer surface 25 and the polygonal inner surface 23 form a positive-locking connection between the shaft section 21 and the hub section 19 ensures that the drive device 1 can be designed to be particularly space-saving and easy to assemble; that is, the shaft section 21 and the hub section 19 can be easily brought into the connected state. Overall, a mechanically robust, space-saving, and easy-to-assemble drive device 1 can thus be provided. In the connected state, the inner surface 23 and the outer surface 25 form a polygonal connection through which a torque can be transmitted between the wheel shaft 17 and the planet carrier 51.In other words, the wheel shaft 17 has a polygonal hub profile and the planet carrier 51 has a polygonal wave profile, with the torque transmission occurring via the polygonal connection formed by the polygonal hub profile of the wheel shaft 17 and the polygonal wave profile of the planet carrier 51. The polygonal connection transmits the torque and simultaneously centers the planet carrier 51 and the wheel shaft 17 relative to each other.

[0028] During the Fig. 4 and Fig. In the schematically illustrated second embodiment of the drive device 1 according to the invention, the hub section 19 has a first cylindrical section 53 with a Fig. 4 schematically shown in section cylindrical inner surface 55, which is provided by a cylindrical bore, and the shaft section 21 has a second cylindrical section 57 with a Fig. The first cylindrical section 53 with the cylindrical inner surface 55 and the cylindrical outer surface 59 are schematically represented. The shaft section 21 and the hub section 19 are connected to each other such that the cylindrical inner surface 55 and the cylindrical outer surface 59 face each other and form a connection between the shaft section 21 and the hub section 19, which can also be described as a precision fit. The planet carrier 51 and the wheel shaft 17 can be centered relative to each other by means of the first cylindrical section 53 with the cylindrical inner surface 55 and the second cylindrical section 57 with the cylindrical outer surface 59.

[0029] The wheel shaft 17 is rotatably mounted on the housing 43 by means of a first tapered roller bearing 29 and a second tapered roller bearing 31. Both the first tapered roller bearing 29 and the second tapered roller bearing 31 are set-right bearings (SR bearings), so that adjustment of the axial preload of the first tapered roller bearing 29 and the second tapered roller bearing 31 is unnecessary. In an alternative embodiment, a shim or shims are arranged between an inner ring 61 of the first tapered roller bearing 29 and the planet carrier 51, so that bearing preload can be applied using the shim or shims.This is particularly advantageous in the case where either the first tapered roller bearing 29 is not a set-right bearing, or the second tapered roller bearing 31 is not a set-right bearing, or neither the first tapered roller bearing 29 nor the second tapered roller bearing 31 is a set-right bearing (SR bearing).

[0030] Furthermore, the information in the Fig. 4 and Fig. Figure 5 schematically illustrates the second embodiment of the drive device 1 according to the invention. A slotted nut 63 is screwed onto a threaded stud 65 of the planet carrier 51. Axial forces between the wheel shaft 17 and the planet carrier 51 can be transmitted by means of the slotted nut 63. Furthermore, axial forces between the wheel shaft 17 and the planet carrier 51 can be transmitted by means of a [missing information - likely a specific component or component] pointing in a first direction 39 and in Fig. 5 mounting surface 67 of the planet carrier 51, marked with a reference symbol, and a second direction 41 pointing in the opposite direction to one of the first directions 39 and in Fig. The contact surface 69 of the wheel shaft 17, marked with a reference numeral, is transferred by these two contact surfaces bearing against each other. The point or area where the two contact surfaces bear against each other can also be referred to as axial contact between the planet carrier 51 and the wheel shaft 17. In the Fig. 4 and Fig. In the schematically illustrated second embodiment of the drive device 1 according to the invention, the planet carrier 51 and the wheel shaft 17 are axially preloaded by means of the slotted nut 63. To ensure axial preload, the slotted nut 63 is screwed onto the threaded stud 65. Because the two contact surfaces are in contact with each other, the screw force generated by the slotted nut 63 can be supported. The shaft section 21 and the hub section 19 are thus mechanically preloaded relative to each other along the direction of extension of the shaft section 21. This mechanical preload ensures that a force-fit exists between the shaft section 21 and the hub section 19, guaranteeing a particularly robust mechanical connection between them.

[0031] During the Fig. 4 and Fig. In the second embodiment of the drive device 1 according to the invention, shown schematically in Figure 5, a transition fit, namely H7 / k6, is provided between the polygonal inner surface 23 and the polygonal outer surface 25. In an alternative embodiment of the drive device 1 according to the invention, which is not shown, a clearance fit, namely H7 / g6, is provided, so that the shaft section 21 and the hub section 19 can be displaced relative to each other without noticeable play along the direction of extension of the shaft section 21. In a further alternative embodiment of the drive device 1 according to the invention, which is also not shown, an interference fit is provided, which can also be referred to as an interference fit. Axial forces can be transmitted between the hub section 19 and the shaft section 21 by means of the interference fit.In this embodiment, the positive-locking connection between the shaft section 21 and the hub section 19 is designed such that the shaft section 21 and the hub section 19 are frictionally connected to each other along the direction of extension of the shaft section 21. Because the positive-locking connection between the shaft section 21 and the hub section 19 is designed such that the shaft section 21 and the hub section 19 are frictionally connected to each other along the direction of extension of the shaft section 21, it is ensured that axial forces acting along the direction of extension of the shaft section 21 between the shaft section 21 and the hub section 19 can be transmitted at least partially, so that, in particular, any further components of the drive device 1 that may be provided, such as the slotted nut 63, do not need to be mechanically robust. In particular, since in the Fig. 4 and Fig. In the schematically illustrated second embodiment of the drive device 1 according to the invention, where both the first tapered roller bearing 29 and the second tapered roller bearing 31 are set-right bearings, axial displacement for bearing adjustment is not required and a relatively tight fit (also a transition fit or a press fit) can be selected for the polygon connection.

[0032] The inner surface 23 and the outer surface 25 are in the Fig. 4 and Fig. 5 schematically illustrated second embodiment of the drive device 1 according to the invention is designed as described in the Fig. 1 to 3 schematically depicted first embodiment of the drive device 1 according to the invention, and the described features, technical effects and / or advantages also apply at least analogously to the inner surface 23 and the outer surface 25 of the device shown in the diagram. Fig. 4 and Fig. 5 schematically illustrated second embodiment of the drive device 1 according to the invention. With the help of the inner surface 23 and the outer surface 25 a positive-locking shaft-hub connection is obtained between the wheel shaft 17 and the planet carrier 51, which can transmit torques, bending moments and transverse forces.

[0033] Even in the Fig. 4 and Fig. Figure 5 schematically illustrates the second embodiment of the drive device 1 according to the invention, which has a mounting section 37 of the wheel shaft 17 to which a vehicle wheel can be attached. The mounting section 37 is rotationally fixed to the second section of the transmission unit 3, which in this example is the planet carrier 51.

[0034] The in the Fig. 6 and Fig. Figure 7, schematically depicted, shows a third embodiment of the drive device 1 according to the invention, comprising a gear unit 3, which can also be described as a spur gear-bevel gear unit. This third embodiment of the drive device 1 according to the invention can be used as a drive system for a forklift or industrial truck and essentially corresponds to the first embodiment of the drive device 1 according to the invention. The gear unit 3 comprises a spur gear stage 5, which can also be described as the first gear stage. The spur gear stage 5 comprises a drive pinion 7 and a spur gear 9. The drive pinion 7 is driven by a machine unit of the drive device 1 (not shown), which in the illustrated embodiment is an electric machine and provides the drive power in the form of torque and speed.The drive pinion 7 can also be described as the first section of the gear unit 3, which can be set into rotary motion by means of the machine unit. The drive pinion 7 and the spur gear 9 are operatively connected via their teeth, so that the drive power is transmitted from the drive pinion 7 to the spur gear 9. In addition to the spur gear stage 5, the gear unit 3 has a bevel gear stage 11, which can also be described as the second gear stage. The bevel gear stage 11 has a bevel gear shaft 13 and a bevel gear 15. The spur gear 9 and the bevel gear shaft 13 are connected to each other by means of a shaft-hub connection, which will be discussed in more detail later, so that the drive power is transmitted from the spur gear stage 5 to the bevel gear stage 11. The bevel gear shaft 13 and the bevel gear 15 are operatively connected via their teeth, so that the drive power is transmitted from the bevel gear shaft 13 to the bevel gear 15.The bevel gear 15 can also be described as the second section of the gear unit 3, which can be set into rotation by the rotational movement of the first section via one or more gear stages. Furthermore, the drive device 1 has a wheel shaft (not shown). Also in the case of the... Fig. 6 and Fig. Figure 7, schematically depicted as the third embodiment of the drive device 1 according to the invention, shows a mounting section (not shown) of a wheel shaft to which a vehicle wheel can be attached. The mounting section is rotationally fixed to the second section of the transmission unit, which in this example is the bevel gear 15.

[0035] The spur gear 9 has a hub section 19 and the bevel gear shaft 13 has a shaft section 21. The drive device 1 thus comprises the hub section 19 and the shaft section 21. The hub section 19 has a polygonal inner surface 23 and the shaft section 21 has a polygonal outer surface 25. The polygonal outer surface 25 and the polygonal inner surface 23 are designed such that when the shaft section 21 and the hub section 19 are arranged relative to each other such that the outer surface 25 and the inner surface 23 face each other, the outer surface 25 and the inner surface 23 form a positive-locking connection between the shaft section 21 and the hub section 19.Then, when the shaft section 21 and the hub section 19 are arranged relative to each other such that the outer surface 25 and the inner surface 23 face each other and the outer surface 25 and the inner surface 23 form a positive-locking connection between the shaft section 21 and the hub section 19, the shaft section 21 and the hub section 19 are in a connected state. Preferably, the shaft section 21 and the hub section 19 are in the connected state.The fact that the polygonal outer surface 25 and the polygonal inner surface 23 form a positive-locking connection between the shaft section 21 and the hub section 19 ensures that a positive-locking polygon connection is provided by means of the inner surface 23 and the outer surface 25, through which torques can be transmitted between the shaft section 21 and the hub section 19, transverse forces acting perpendicular to a direction of extension of the shaft section 21 can be transmitted between the shaft section 21 and the hub section 19, bending moments can be transmitted between the shaft section 21 and the hub section 19, and in addition, the shaft section 21 and the hub section 19 can be centered relative to each other, thus ensuring smooth running.Furthermore, the fact that the polygonal outer surface 25 and the polygonal inner surface 23 form a positive-locking connection between the shaft section 21 and the hub section 19 ensures that the drive device 1 can be designed to be particularly space-saving and easy to assemble; that is, the shaft section 21 and the hub section 19 can be easily brought into the connected state. Overall, a mechanically robust, space-saving, and easy-to-assemble drive device 1 can thus be provided. In the connected state, the spur gear 9 and the bevel gear shaft 13 are arranged concentrically with respect to the teeth of the spur gear 9. In other words, the spur gear 9 has a polygonal hub profile aligned concentrically with the teeth of the spur gear 9, and the bevel gear shaft 13 has a polygonal shaft profile.

[0036] The inner surface 23 and the outer surface 25 are in the Fig. 6 and Fig. 7 schematically illustrated third embodiment of the drive device 1 according to the invention is designed as described in the Fig. 1 to 3 schematically depicted first embodiment of the drive device 1 according to the invention and in the Fig. 4 and Fig. 5 schematically illustrated second embodiment of the drive device 1 according to the invention, and the described features, technical effects and / or advantages also apply at least analogously to the inner surface 23 and the outer surface 25 of the device shown in the Fig. 6 and Fig. 7 schematically illustrated third embodiment of the drive device according to the invention 1. By means of the inner surface 23 and the outer surface 25 a positive locking shaft-hub connection is obtained between the spur gear 9 and the bevel gear shaft 13, which can transmit torques, bending moments and transverse forces.

[0037] The positive-locking connection between shaft section 21 and hub section 19 is designed such that shaft section 21 and hub section 19 are displaceable relative to each other along one direction of extension of shaft section 21. The spur gear 9 is displaceable on the bevel gear shaft 13 in the axial direction, i.e., along the direction of extension of shaft section 21. In the Fig. 6 and Fig. Figure 7 shows a rotation axis 27 along which the direction of extension of the shaft section 21 runs in the assembled state. In the Fig. 6 and Fig. In the third embodiment of the drive device 1 according to the invention, shown schematically in Figure 7, a clearance fit, namely H7 / g6, is provided, such that the shaft section 21 and the hub section 19 can be displaced relative to each other without noticeable play along the direction of extension of the shaft section 21. In an alternative embodiment of the drive device 1 according to the invention, not shown, a transition fit, namely H7 / k6, is provided. In a further alternative embodiment of the drive device 1 according to the invention, also not shown, an interference fit is provided, which can also be referred to as an interference fit. Axial forces can be transmitted between the hub section 19 and the shaft section 21 by means of the interference fit.In this embodiment, the positive-locking connection between the shaft section 21 and the hub section 19 is designed such that the shaft section 21 and the hub section 19 are frictionally connected to each other along the direction of extension of the shaft section 21. Because the positive-locking connection between the shaft section 21 and the hub section 19 is designed such that the shaft section 21 and the hub section 19 are frictionally connected to each other along the direction of extension of the shaft section 21, it is ensured that axial forces acting along the direction of extension of the shaft section 21 between the shaft section 21 and the hub section 19 can be at least partially transmitted, so that, in particular, any further components of the drive device 1 that may be provided, such as the first nut 33 and the second nut 35, do not need to be mechanically robust.

[0038] The in the Fig. Figures 6 to 7, schematically depicting the third embodiment of the drive device 1 according to the invention, also includes a first tapered roller bearing 29, a second tapered roller bearing 31, a first nut 33, and a second nut 35. The bearing preload of both the first tapered roller bearing 29 and the second tapered roller bearing 31 can be adjusted by means of the tightening torque of the first nut 33. In particular, because the positive-locking connection between the shaft section 21 and the hub section 19 is designed such that the shaft section 21 and the hub section 19 are displaceable relative to each other along the direction of extension of the shaft section 21, the bearing preload of both the first tapered roller bearing 29 and the second tapered roller bearing 31 can be adjusted by means of the tightening torque of the first nut 33.For this purpose, the first nut 33 is placed on a thread of the shaft section 21 and screwed onto the thread in the direction of the teeth of the bevel gear shaft 13. Furthermore, a first section of an inner ring of the first tapered roller bearing 29 rests against a contact surface of the hub section 19 pointing in a first direction 39, which runs along the extension direction of the shaft section 21, and a second section of an outer ring of the first tapered roller bearing 29 rests against a contact surface of a housing 43 of the drive device 1 pointing in a second direction 41 opposite to the first direction 39. Additionally, a first section of an inner ring of the second tapered roller bearing 31 rests against a contact surface of the shaft section 21 pointing in the second direction 41, and a second section of an outer ring of the second tapered roller bearing 31 rests against a contact surface of the housing 43 of the drive device 1 pointing in the first direction 39.After adjusting the bearing preload of the first tapered roller bearing 29 and the second tapered roller bearing 31, the second nut 35 is tightened against the first nut 33. This securely clamps both the first nut 33 and the second nut 35 onto a threaded journal 45 of the bevel gear shaft 13, which provides the thread. This allows axial forces between the spur gear 9 and the bevel gear shaft 13, and from these two components to the first tapered roller bearing 29 and the second tapered roller bearing 31, and thus to the housing 43, which can also be referred to as the gearbox housing. The shaft section 21 and the hub section 19 are therefore secured against displacement relative to each other along their direction of travel. Specifically, the shaft section 21 and the hub section 19 are secured against displacement relative to each other along their direction of travel by means of the first nut 33 and the second nut 35.

[0039] The in the Fig. 8 and Fig. Figure 9, schematically depicted, shows a fourth embodiment of the drive device 1 according to the invention, comprising a gear unit 3, which can also be described as a spur gear-bevel gear unit. This fourth embodiment of the drive device 1 according to the invention can be used as a drive system for a forklift or industrial truck and essentially corresponds to the first and third embodiments of the drive device 1 according to the invention. The gear unit 3 comprises a spur gear stage 5, which can also be described as the first gear stage. The spur gear stage 5 comprises a drive pinion 7 and a spur gear 9. The drive pinion 7 is driven by an output shaft 71 of a machine unit 47 of the drive device 1, which is rotatable about a pivot axis 27.In the illustrated embodiment, the machine unit 47 is an electric machine and provides the drive power in the form of torque and rotational speed. The drive pinion 7 can also be referred to as the first section of the gear unit 3, which can be set into rotary motion by means of the machine unit. The drive pinion 7 and the spur gear 9 are operatively connected via their teeth, so that the drive power is transmitted from the drive pinion 7 to the spur gear 9. The [details omitted] Fig. 8 and Fig. Figure 9, schematically depicted as a fourth embodiment of the drive device 1 according to the invention, also features a bevel gear (not shown), which can also be referred to as the second section of the gear unit 3. This bevel gear can be set into rotation by the rotational movement of the first section via one or more gear stages. Furthermore, a wheel shaft (not shown) and a mounting section for the wheel shaft are provided, to which a [missing information] Fig. The vehicle wheel shown in section 8 can be attached. The mounting section is rotationally fixed to the second section of the transmission unit 3, which in this example is the bevel gear.

[0040] The drive pinion 7 has a hub section 19 and the output shaft 71 has a shaft section 21. The drive device 1 thus comprises the hub section 19 and the shaft section 21. The hub section 19 has a polygonal inner surface 23 and the shaft section 21 has a polygonal outer surface 25. The polygonal outer surface 25 and the polygonal inner surface 23 are designed such that when the shaft section 21 and the hub section 19 are arranged relative to each other such that the outer surface 25 and the inner surface 23 face each other, the outer surface 25 and the inner surface 23 form a positive-locking connection between the shaft section 21 and the hub section 19.Then, when the shaft section 21 and the hub section 19 are arranged relative to each other such that the outer surface 25 and the inner surface 23 face each other and the outer surface 25 and the inner surface 23 form a positive-locking connection between the shaft section 21 and the hub section 19, the shaft section 21 and the hub section 19 are in a connected state. Preferably, the shaft section 21 and the hub section 19 are in the connected state.The fact that the polygonal outer surface 25 and the polygonal inner surface 23 form a positive-locking connection between the shaft section 21 and the hub section 19 ensures that a positive-locking polygon connection is provided by means of the inner surface 23 and the outer surface 25, through which torques can be transmitted between the shaft section 21 and the hub section 19, transverse forces acting perpendicular to a direction of extension of the shaft section 21 can be transmitted between the shaft section 21 and the hub section 19, bending moments can be transmitted between the shaft section 21 and the hub section 19, and in addition, the shaft section 21 and the hub section 19 can be centered relative to each other, thus ensuring smooth running.Furthermore, the fact that the polygonal outer surface 25 and the polygonal inner surface 23 form a positive-locking connection between the shaft section 21 and the hub section 19 ensures that the drive device 1 can be designed to be particularly space-saving and easy to assemble; that is, the shaft section 21 and the hub section 19 can be easily brought into the connected state. Overall, a mechanically robust, space-saving, and easy-to-assemble drive device 1 can thus be provided. In the connected state, the drive pinion 7 and the output shaft 71 are arranged concentrically with respect to the teeth of the drive pinion 7. In other words, the drive pinion 7 has a polygonal hub profile aligned concentrically with the teeth of the drive pinion 7, and the output shaft 71 has a polygonal shaft profile.

[0041] The inner surface 23 and the outer surface 25 are in the Fig. 8 and Fig. 9 schematically illustrated fourth embodiment of the drive device 1 according to the invention is designed as described in the Fig. Figures 1 to 3 schematically illustrate the first embodiment of the drive device 1 according to the invention, in which the Fig. 4 and Fig. 5 schematically illustrated second embodiment of the drive device 1 according to the invention and in the Fig. 6 and Fig. 7 schematically illustrated third embodiment of the drive device 1 according to the invention, and the described features, technical effects and / or advantages also apply at least analogously to the inner surface 23 and the outer surface 25 of the device shown in the Fig. 8 and Fig. 9 schematically illustrated fourth embodiment of the drive device according to the invention 1. By means of the inner surface 23 and the outer surface 25 a positive-locking shaft-hub connection is obtained between the drive pinion 7 and the output shaft 71, which can transmit torques, bending moments and transverse forces.

[0042] The in the Fig. 8 and Fig. Figure 9, a schematically illustrated fourth embodiment of the drive device 1 according to the invention, also includes a disk 73 and a retaining ring 75, which is arranged section by section in a groove of the output shaft 71 that rotates around the axis of rotation 27 and opens away from the axis of rotation 27. The groove can also be referred to as a retaining ring groove. Furthermore, the output shaft 71 forms a shoulder 77. The shoulder 77 has a contact surface pointing in a first direction 39. The drive pinion 7 rests against the contact surface of the shoulder 77 with a contact surface pointing in a second direction 41 opposite to the first direction 39.Furthermore, the drive pinion 7 rests with a contact surface facing in the first direction 39 against a contact surface of the disk 73 facing in the second direction 41, which in turn rests with a contact surface facing in the first direction 39 against a contact surface of the retaining ring 75 facing in the second direction 41, the retaining ring 75 being arranged at least partially in the groove as already described. Axial forces between the drive pinion 7 and the output shaft 71 can be transmitted by means of the contact surfaces. The shaft section 21 and the hub section 19 are thus secured against displacement relative to each other along a direction of extension of the shaft section 21. Specifically, the shaft section 21 and the hub section 19 are secured against displacement relative to each other along this direction of extension by means of the shaft shoulder 77 and the retaining ring 75.

[0043] The in the Fig. 10 and Fig. Figure 11, schematically depicting the fifth embodiment of the drive device 1 according to the invention, comprises a gear unit 3 and a machine unit 47. This fifth embodiment of the drive device 1 according to the invention can be used as a steering drive for a counterbalance forklift. The drive device 1 has an axle carrier 79 and a spur gear 81 of an output stage 83 of the gear unit 3. The spur gear 81 can also be referred to as the second section of the gear unit 3, which can be set into rotation by the rotational movement of the first section via one or more gear stages. The axle carrier 79 has a mounting section 37 to which further components of the drive device 1 can be attached. The mounting section 37 is rotationally fixed to the second section of the gear unit 3, which in this example is the spur gear 81.

[0044] The spur gear 81 has a hub section 19 and the axle carrier 79 has a shaft section 21. The drive device 1 thus comprises the hub section 19 and the shaft section 21. The hub section 19 has a polygonal inner surface 23 and the shaft section 21 has a polygonal outer surface 25. The polygonal outer surface 25 and the polygonal inner surface 23 are designed such that when the shaft section 21 and the hub section 19 are arranged relative to each other such that the outer surface 25 and the inner surface 23 face each other, the outer surface 25 and the inner surface 23 form a positive-locking connection between the shaft section 21 and the hub section 19.Then, when the shaft section 21 and the hub section 19 are arranged relative to each other such that the outer surface 25 and the inner surface 23 face each other and the outer surface 25 and the inner surface 23 form a positive-locking connection between the shaft section 21 and the hub section 19, the shaft section 21 and the hub section 19 are in a connected state. Preferably, the shaft section 21 and the hub section 19 are in the connected state.The fact that the polygonal outer surface 25 and the polygonal inner surface 23 form a positive-locking connection between the shaft section 21 and the hub section 19 ensures that a positive-locking polygon connection is provided by means of the inner surface 23 and the outer surface 25, through which torques can be transmitted between the shaft section 21 and the hub section 19, transverse forces acting perpendicular to a direction of extension of the shaft section 21 can be transmitted between the shaft section 21 and the hub section 19, bending moments can be transmitted between the shaft section 21 and the hub section 19, and in addition, the shaft section 21 and the hub section 19 can be centered relative to each other, thus ensuring smooth running.Furthermore, the fact that the polygonal outer surface 25 and the polygonal inner surface 23 form a positive-locking connection between the shaft section 21 and the hub section 19 ensures that the drive device 1 can be designed to be particularly space-saving and easy to assemble; that is, the shaft section 21 and the hub section 19 can be easily brought into the connected state. Overall, a mechanically robust, space-saving, and easy-to-assemble drive device 1 can thus be provided. In the connected state, the axle carrier 79 and the spur gear 81 are arranged concentrically with respect to the teeth of the spur gear 81. In other words, the spur gear 81 has a polygonal hub profile aligned concentrically with the teeth of the spur gear 81, and the axle carrier 79 has a polygonal shaft profile.

[0045] The inner surface 23 and the outer surface 25 are in the Fig. 10 and Fig. 11 schematically illustrated fifth embodiment of the drive device 1 according to the invention is designed as described in the Fig. Figures 1 to 3 schematically illustrate the first embodiment of the drive device 1 according to the invention, in which the Fig. 4 and Fig. 5 schematically illustrated second embodiment of the drive device 1 according to the invention, in which in the Fig. 6 and Fig. 7 schematically illustrated third embodiment of the drive device 1 according to the invention and in the Fig. 8 and Fig. 9 schematically illustrated fourth embodiment of the drive device 1 according to the invention, and the described features, technical effects and / or advantages also apply at least analogously to the inner surface 23 and the outer surface 25 of the device shown in the Fig. 10 and Fig. 11 schematically illustrated fifth embodiment of the drive device according to the invention 1. By means of the inner surface 23 and the outer surface 25 a positive-locking shaft-hub connection is obtained between the axle carrier 79 and the spur gear 81, which can transmit torques, bending moments and transverse forces.

[0046] The in the Fig. 10 and Fig.Figure 11, schematically depicted as the fifth embodiment of the drive device 1 according to the invention, further comprises a disk 73 and a retaining ring 75, which is arranged section by section in a groove 85 of the axle carrier 79 that rotates around an axis of rotation 27 and opens away from the axis of rotation 27. The groove 85 can also be referred to as a retaining ring groove. The axle carrier 79 also forms a shaft shoulder 77. The shaft shoulder 77 has a contact surface pointing in a first direction 39. The spur gear 81 rests against the contact surface of the shaft shoulder 77 with a contact surface pointing in a second direction 41 opposite to the first direction 39.Furthermore, the spur gear 81 rests with a contact surface facing in the first direction 39 against a contact surface of the disk 73 facing in the second direction 41, which in turn rests with a contact surface facing in the first direction 39 against a contact surface of the retaining ring 75 facing in the second direction 41, the retaining ring 75 being arranged, as already described, at least partially in the groove 85. Axial forces between the axle carrier 79 and the spur gear 81 can be transmitted by means of the contact surfaces. The shaft section 21 and the hub section 19 are thus secured against displacement relative to each other along a direction of extension of the shaft section 21. Specifically, the shaft section 21 and the hub section 19 are secured against displacement relative to each other along this direction of extension by means of the shaft shoulder 77 and the retaining ring 75.

[0047] If, in connection with the present invention, a positive-locking connection between the shaft section 21 and the hub section 19 is defined such that the polygonal outer surface 25 and the polygonal inner surface 23 form a positive-locking connection between the shaft section 21 and the hub section 19, this connection can also be referred to as a polygon connection. In connection with the exemplary embodiments, different sections of the drive device 1 have been described in which such a polygon connection can be provided, with different components forming the inner surface 23 and the outer surface 25, respectively. The present invention comprises drive devices in which only one polygon connection is provided.The present invention also includes drive devices in which several polygon connections are provided, each polygon connection being arranged in a different section of the drive device 1, with different components forming the corresponding inner surface 23 and the corresponding outer surface 25. When reference is made to transverse forces in connection with the present invention, these are primarily forces acting perpendicular to the direction of extension of the shaft section 21. The transverse forces can also be referred to as radial forces and preferably act perpendicular to the axis of rotation 27, i.e., in a radial direction relative to the axis of rotation 27.

[0048] Another aspect of the invention is a forklift truck with a drive device 1 according to one of the described embodiments. The features, technical effects and / or advantages described in connection with the drive device 1 also apply, at least analogously, to the forklift truck, so a corresponding repetition is omitted here.

[0049] It should be further noted that "having" does not exclude any other elements or steps, and "a" or "an" does not exclude a plurality. It should also be noted that features described with reference to one of the above embodiments may also be used in combination with other features of other embodiments described above. Reference numerals in the claims are not to be considered as a limitation. Reference sign 1 Drive device 3 Gear unit 5 spur gear stage 7 drive pinions 9 Spur gear 11 bevel gear stage 13 bevel gear shaft 15 bevel gear 17 Wheel shaft 19 Hub section 21 Wave section 23 polygonal interior surfaces 25 polygonal outer surface 27 axis of rotation 29 first tapered roller bearing 31 second tapered roller bearing 33 first mother 35 second mother 37 Fastening section 39 first direction 41 second direction 43 cases 45 threaded studs 47 machine units 49th planetary stage 51 planetary carriers 53 first cylindrical section 55 cylindrical inner surface 57 second cylindrical section 59 cylindrical outer surface 61 inner ring 63 Nut 65 threaded studs 67 Mounting surface of the planetary carrier 69 Contact surface of the wheel shaft 71 Output shaft 73 discs 75 retaining ring 77 wave step 79 axle carriers 81 Spur gear 83 Output stage 85 Nut

Claims

[1] Drive device (1) for a forklift truck, wherein the drive device (1) a wave section (21) and has a hub section (19), wherein the wave section (21) has a polygonal outer surface (25) and the hub section (19) has a polygonal inner surface (23), and wherein the polygonal outer surface (25) and the polygonal inner surface (23) are designed such that when the shaft section (21) and the hub section (19) are arranged relative to each other such that the outer surface (25) and the inner surface (23) face each other, the outer surface (25) and the inner surface (23) form a positive locking connection between the shaft section (21) and the hub section (19). [2] Drive device (1) according to the preceding claim, wherein the positive locking connection between the shaft section (21) and the hub section (19) is designed such that along an extension direction of the shaft section (21) the shaft section (21) and the hub section (19) are displaceable relative to each other. [3] Drive device (1) according to claim 1, wherein the positive locking connection between the shaft section (21) and the hub section (19) is designed such that along the extension direction of the shaft section (21) the shaft section (21) and the hub section (19) are force-locked together. [4] Drive device (1) according to one of the preceding claims, wherein the shaft section (21) and the hub section (19) are secured against displacement relative to each other along the direction of extension. [5] Drive device (1) according to the preceding claim 4, wherein the shaft section (21) and the hub section (19) are secured against displacement relative to each other along the direction of extension by means of a nut or by means of several nuts. [6] Drive device (1) according to one of the preceding claims 4 or 5, wherein the shaft section (21) and the hub section (19) are secured against displacement relative to each other along the direction of extension by means of a shaft shoulder (77). [7] Drive device (1) according to one of the preceding claims 4, 5 or 6, wherein the shaft section (21) and the hub section (19) are secured against displacement relative to each other along the direction of extension by means of a retaining ring (75). [8] Drive device (1) according to one of the preceding claims, wherein the shaft section (21) and the hub section (19) are mechanically preloaded relative to each other along the extension direction of the shaft section (21). [9] Drive device (1) according to one of the preceding claims, wherein the drive device (1) comprises a machine unit (47), a gear unit (3) with a first section which can be set into rotary motion by means of the machine unit (47), and with a second section which can be set into rotary motion by the rotary motion of the first section via one or more gear stages, and a fastening section (37) which is non-rotatably connected to the second section of the gear unit (3). [10] Industrial truck with a drive device (1) according to one of the preceding claims.

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