GEARBOX AND AGRICULTURAL MACHINE WITH SUCH A

Description

[0001] The invention relates to a transmission device comprising a first drive element, a second drive element, a shift sleeve designed as a hollow shaft, and an output shaft. The shift sleeve is axially displaceable on the output shaft and can be moved axially into a first, second, or third shift position. The first and second drive elements each have internal teeth, the shift sleeve has external teeth and internal teeth, and the output shaft has external teeth. In the first shift position, the external teeth of the shift sleeve form a first gear pair with the internal teeth of the first drive element. In the second shift position, the external teeth of the shift sleeve form a second gear pair with the internal teeth of the second drive element. Furthermore, the internal teeth of the shift sleeve form a third gear pair with the external teeth of the output shaft.

[0002] Gearboxes and drive devices with gearboxes for driven processing units on harvesting machines are known and are used in various forms and in a wide range of applications. For example, DE 2 745 564 C2 discloses a drive device for a processing unit of a combine harvester, with a belt drive and a pulley arranged on a hollow shaft concentric with a main drive shaft.A drive gear is arranged on the hollow shaft and a switching element is provided which is axially displaceable in two positions and selectively connects the main drive shaft with a gear of different direction of rotation that is connected to the drive gear, wherein in a first position the switching element connects a sun gear of a planetary gear set via planet gears and a second sun gear set to the main drive shaft and in a second position connects the sun gear of the planetary gear set to the main drive shaft via planet gears and a ring gear carrier.

[0003] DE 2 744 344 C3 also discloses a drive device for harvesting machines with a belt drive, which has a driven pulley rotatably mounted on an output shaft. The belt drive can be connected directly or indirectly to an output shaft, for example to an output shaft for a threshing drum, either directly or via an optionally engageable reduction gear.

[0004] Other transmission devices in conjunction with belt drives are also known from the prior art, which are used in agricultural machinery, in particular harvesting machines with processing units for the harvested crop. These include, for example, combine harvesters, forage harvesters, sugar cane harvesters, or other harvesting machines that provide for processing of the harvested crop within the machine. Thus, threshing, chopping, cutting, or another type of processing may be provided during the harvesting process, with different drive stages and therefore speed variations being provided for the processing units, such as a chopping drum. Such a transmission device is disclosed in DE 102019213717 A1.The transmission assembly comprises a shifting device with a transmission shaft and a shift gear mounted thereon, the shift gear being designed with a shift sleeve that is axially displaceable relative to the transmission shaft. The shift sleeve has internal teeth that engage with external teeth on the transmission shaft, so that the shift sleeve, together with the shift gear, is axially displaceable on the transmission shaft and thus in drive connection with it. The shift sleeve with the shift gear is axially displaceable into several shift positions, so that two drive stages, in which the shift gear is connected to different drive gears of a planetary gear set, and a neutral position can be set.

[0005] In the aforementioned transmission devices, only one pulley is provided on the drive side. However, in the case of a fixed pulley, as in the last-mentioned document, a transmission device in the form of a planetary gear is provided, which is operated via the shift gear to obtain different output speeds. The transmission and shifting device is therefore complex and requires additional installation space. Furthermore, it is costly.

[0006] To avoid the aforementioned complex and elaborate transmission systems, gearboxes are also offered in conjunction with belt drives. These gearboxes feature two pulleys on the drive side, allowing for different speeds or gear ratios to be achieved by engaging and disengaging the respective pulleys. Such gearboxes with two pulleys are used, for example, in the belt drives of combine harvesters with chopping units or other equipment for processing harvested crops (such as threshing or cutting). These belt drives with two pulleys can also be used to drive blower systems in harvesting machines. The chopping units mentioned above include chopping drums driven by such a belt drive.The different speeds serve, for example, to adapt the chopping unit to the crop being harvested, as well as to the operator's requirements, such as varying the chop length. Furthermore, the operator may also desire threshing operations without subsequent chopping. The belt drives for the chopping units are typically connected to the harvester's drive motor via a pulley. Thus, the chopping unit is generally directly linked to the drive motor's speed, meaning that components such as seals, bearings, and lubrication are also directly affected by the motor's speed. These components are typically designed for a maximum speed range in chopping units, which could be exceeded at high drive motor speeds.At excessively high speeds, the aforementioned components would be exposed to the associated high temperatures, potentially leading to damage and premature wear, particularly in the seals. To prevent this, it is advisable to adjust the drive ratio of the chopping unit if the drive motor speed is too high, or to reduce any excessively high speed of the chopping unit itself, thus avoiding excessively high speeds for these components. It is also recommended to incorporate a device that allows the chopping unit to be selectively decoupled from the drive motor. Belt drives are also used in similar applications for other processing units on harvesting machines.During harvesting, the crop flow can involve threshing, chopping, cutting, or other processing methods. These methods utilize various drive stages, such as a chopping drum, allowing for variable speeds. Ultimately, the aforementioned drive systems are used in a wide variety of harvesting machines with belt drives for diverse processing attachments, including combine harvesters, forage harvesters, sugarcane harvesters, and balers.

[0007] In addition to the disadvantages already described, which a complex transmission device with planetary gears according to DE 102019213717 A1 entails, another disadvantage is that the shift gear belonging to the switching device must be engaged from the neutral position into the shift position and, before engagement, aligned relatively precisely with the respective drive gear of the planetary gear by means of the axially displaceable shift sleeve. This occurs when the teeth of the shift gear do not align with the tooth gaps of the drive gears and the respective tooth faces collide, so that in the neutral position, manual alignment or rotation of the shift sleeve or the respective drive gear is first necessary. Only then is it possible to engage the shift gear from the neutral position and mesh with the teeth of the respective drive gear.Due to a standardized, relatively small radial backlash between the teeth, the engagement position of the shift sleeve or gear must be very precise. This often proves to be quite difficult, as both the shift sleeve and the drive gears are connected to other drive or driven components, and manually rotating the shift sleeve or the corresponding drive element requires a relatively high force. The shifting process, or the precise manual alignment or rotation of the shift sleeve, is therefore often problematic and time-consuming.

[0008] The design and manufacture of gears is based on gear standards, such as DIN 780. According to DIN 780, a standardized gear module is used as a measure of the tooth size of gears. The standardized gear module m is calculated by dividing the pitch circle diameter d of the gear by the number of teeth z of the gear, resulting in m = d / z. To simplify the selection of compatible gears and to enable the use of standardized tools, DIN 780 defines preferred series in which a tooth pitch pm is specified for a given standardized gear module m. The tooth pitch pm is defined as the ratio of the gear circumference U at the pitch circle (with pitch circle diameter d) to the number of teeth z, i.e., pm = U / z. Using the mathematical constant π = U / d, or U = π * d, it follows that the tooth pitch pm is defined by pm = π * d / z or pm = π * m.The tooth pitch pm is thus also defined as the arc length on the pitch circle (with pitch circle diameter d) between two identical points lying on the pitch circle of two adjacent teeth of a gear with normalized tooth module m.

[0009] The object underlying the invention is seen as being to provide a transmission device of the type mentioned above with which switching operations can be carried out in a simplified manner.

[0010] The problem is solved according to the invention by the teaching of claim 1. Further advantageous embodiments and developments of the invention are set forth in the dependent claims.

[0011] According to the invention, a gear unit of the type mentioned above is designed such that the first, second, and third gear pairs have a tooth pitch p approximately twice the pitch of standardized gear modules, resulting in a tooth spacing approximately twice the pitch. The tooth spacing is understood as the distance between two identical points of two adjacent teeth on the pitch circle. The tooth spacing thus directly influences the tooth gap width or tooth interspace length at the level of the pitch circle, in each case in the circumferential direction. With such a gear design, the tooth spacing in the respective gear pairs is doubled compared to a standardized gear pair, while the tooth geometry, i.e., the shape and size of the teeth, is maintained according to the tooth geometry associated with the standardized tooth modules.The ratio of tooth gap width or tooth space length to tooth width is thereby approximately tripled at the height of the pitch circle diameter (from approximately 1 (single tooth gap) to approximately 3 (triple tooth gap)). For a gear pair with an even number of teeth in each tooth (gears with an even number of teeth), a gear pair according to the invention is obtained, for example, by the fact that the latter is formed with only every second tooth compared to a standardized gear pair (with an even number of teeth in each tooth). Or conversely, a gear pair according to the invention is obtained by forming only every second tooth in the standardized gear pair (with an even number of teeth in each tooth) with standardized tooth modules.In other words, a gear pair according to the invention is obtained by removing every second tooth from the standardized gear pair with standardized tooth modules (with an even number of teeth in each tooth). For example, a gear pair according to the invention is obtained by modifying a gear pair consisting of an internal tooth and an external tooth according to standardized tooth modules with tooth module m, diameter d, and a number of teeth of 28, such that, with the same tooth module m and diameter d, a number of teeth of 14 is obtained. This approximately triples the tooth gap available for the teeth to engage (tooth gap widths or tooth space lengths), from approximately one tooth width (according to the standard) to approximately three tooth widths.The tooth pitch p, which is approximately twice as large (compared to a tooth pitch pm assigned according to a standardized tooth module), is also applied to the third pair of teeth on the inside of the shift sleeve, thus increasing the tooth spacing there as well from approximately one tooth width to approximately three tooth widths (in each case, relative to the pitch circle of the gearing). This creates a limited freewheel for the shift sleeve in both circumferential directions, as it can now rotate a certain amount in every shift position without any engagement of the teeth, neither from the drive elements nor from the output shaft. The limited freewheel covers approximately one arc length of the pitch circle equal to two tooth widths on the pitch circle.In other words, the limited free play across two tooth widths ensures that every possible overlap condition during a shift from one gear position to another (i.e., every possible misalignment during engagement) can be overcome. This allows the shift sleeve, with its external teeth, to be rotated and aligned into the tooth gaps of the drive elements without any opposing forces or torques from the output shaft or any connected output train. Rotating or aligning the shift sleeve can be done virtually torque-free, enabling shifting operations to be performed with almost no effort.

[0012] In a further embodiment of the invention, annular grooves are formed on the inside of the shift sleeve, and each shift position is assigned an annular groove. These grooves can be engaged by axially sliding the shift sleeve along the output shaft with a detent pin mounted in the output shaft under spring tension. The detent pin, which can be inserted into the annular grooves by axially sliding the shift sleeve, secures the shift sleeve in its various shift positions. Thus, an annular groove is provided on the radial inside of the shift sleeve for each shift position (for the shift positions in which the shift sleeve is fully engaged in the first or second drive element, and for the shift position in which neutral operation is achieved, i.e., in which the shift sleeve is not engaged in either drive element).The detent pin, mounted in the output shaft, can engage in the corresponding annular groove in any given shift position due to spring preload, thus securing the shift sleeve. The spring preload of the detent pin is designed so that it can be easily disengaged from the respective annular groove by manually moving the shift sleeve axially.

[0013] An actuating knob can be provided at one axially exposed end of the shift sleeve for axial adjustment and rotational alignment (twisting the shift sleeve). This allows for convenient and practical handling of the shift sleeve when changing the shift position, especially when the shift sleeve is axially displaced and / or rotated relative to the output shaft.

[0014] In a further embodiment of the invention, the output shaft is designed as a hollow shaft and provided with internal teeth. This enables a simple drive connection with an externally toothed connecting shaft, which is to be driven by the transmission unit, for example a connecting shaft for a chopping, threshing, cutting or blowing unit on a harvesting machine.

[0015] The drive unit is particularly suitable for belt drives, where, on the drive side, the first and second drive elements each comprise a pulley and are connected to a belt drive. The pulleys can have different outer diameters to achieve speed variation at the same belt speeds. It is also possible to provide speed variation by using different belt speeds on the respective pulleys.

[0016] The gearbox is suitable as a drive component in the belt drive of a harvesting machine, such as a combine harvester, forage harvester, mower, baler, sugarcane harvester, or cotton picker. Each of these harvesting machines has drive or auxiliary units powered by belt drives, which often require different drive speeds depending on the application and harvesting conditions. For example, in very dense crops, it may be necessary to operate the harvesting machine at a high drive speed, but the speed dependency of the auxiliary drive or auxiliary unit due to the high drive speed must be reduced to prevent overheating or overloading.

[0017] Based on the drawings, which show an embodiment of the invention (in particular Figures 2 to 5The invention, as well as further advantages and advantageous developments and embodiments of the invention, are described and explained in more detail below.

[0018] They show: Fig. 1 a schematic side view of a harvesting machine with a belt drive. Fig. 2 a schematic cross-sectional view of a gear unit for a belt drive. Figure 1 , in an idle position, Fig. 3 a schematic cross-sectional view of the transmission assembly made of Figure 2 , in a first switching position Fig. 4 a schematic cross-sectional view of a gear unit made of Figure 2 , in a second switching position, Fig. 5 a schematic cross-sectional view of gear pairings in the transmission device from Figure 2 , 3 and 4 .

[0019] Figure 1Figure 10 shows a self-propelled agricultural machine, exemplified by a combine harvester. It is also conceivable that the embodiment described below could be implemented on a different type of self-propelled agricultural machine, for example a forage harvester, a mowing machine, a sugarcane harvester, or a baler.

[0020] The agricultural machine 10 comprises a machine housing 12 and a first processing unit 14 in the form of a threshing unit 16 with an axial rotor aligned longitudinally with the agricultural machine 10. The agricultural machine 10 is driven by an internal combustion engine 18 (shown only schematically). The internal combustion engine 18 is connected at its output to a belt drive 20, which drives a processing unit, in this case a chopping unit 22 with a chopping drum 24. The belt drive 20 comprises a first and a second drive belt 26, 28, wherein the first drive belt 26 is connected to a first drive element 32 of a transmission unit 34, comprising a pulley 30, and the second drive belt 28 is connected to a second drive element 38 of the transmission unit 34, comprising a pulley 36.The gearbox 34 is used to drive the chopping unit 22 with two speed stages.

[0021] In the Figures 2 and 3 Further details of the transmission assembly 34 are shown. In this example, the transmission assembly 34 is designed as part of the belt drive 20 (not shown in detail) and comprises the pulleys 30 and 36, which each form part of the first and second drive elements 32 and 38, respectively. The first and second pulleys 30 and 36 are driven and set in rotation by the first and second drive belts 26 and 28, respectively.

[0022] The transmission assembly 34 comprises an output shaft 40 which rotates about an axis of rotation 42. The output shaft 40 is formed with external teeth 44. A shift sleeve 46, designed as a hollow shaft, is axially displaceable and rotationally symmetrical about the axis of rotation 42 on the output shaft 40, the shift sleeve 46 having internal teeth 48 and external teeth 50. The internal teeth 48 of the shift sleeve 46 are in drive connection with the external teeth 44 of the output shaft 40.

[0023] The first drive element 32 comprises, in addition to the pulley 30, a drive hub 52 which is bolted to the pulley 30 in a rotationally fixed manner. The drive hub 52 of the first drive element 32 is provided with an internal toothing 54 which can be engaged with the external toothing 50 of the shift sleeve 46 by axially displacing the latter. In other words, the first drive element 32 has an internal toothing 54 which can be engaged with the external toothing 50 of the shift sleeve 46. The second drive element 38 is equipped with a drive hub 56 formed in the pulley 36, wherein the pulley 36 and the drive hub 56 are formed monolithically, i.e., as a single piece. The drive hub 56 of the second drive element 38 is also provided with an internal toothing 58, which can also be brought into engagement with the external toothing 50 of the switching sleeve 46 by axially displacing the latter.In other words, the second drive element 38 also has an internal toothing 58 which can engage with the external toothing 50 of the shift sleeve 46. The internal toothing 54 of the first drive element 32, the external toothing 50 of the shift sleeve 46, and the internal toothing 58 of the second drive element 38 are dimensioned and spaced axially to the axis of rotation 42 such that the external toothing 50 of the shift sleeve 46 can be completely disengaged from the internal toothing 54 of the first drive element 32 or from the second internal toothing 58 of the second drive element 38 and positioned between the two internal toothings 54, 58 without being in drive connection with either of the two internal toothings 54, 58.In other words, the switching sleeve 46 can be moved into three switching positions: a first (drive-related) switching position in which the external toothing 50 of the switching sleeve 46 engages in the internal toothing 54 of the first drive element 32; a second (drive-related) switching position in which the external toothing 50 of the switching sleeve 46 engages in the internal toothing 58 of the second drive element 38; and a third switching position in which the external toothing 50 of the switching sleeve 46 is positioned axially between the two internal toothings 54, 58 of the first and second drive elements 32, 38, respectively. The third switching position represents an idle position without a drive connection, whereby the external toothing 50 of the switching sleeve 46 is disengaged from one of the two internal toothings 54, 58 and a drive connection with one of the two internal toothings 54, 58 has been correspondingly disconnected.

[0024] The pulley 30 of the first drive element 32 is rotatably mounted on the drive hub 56 of the pulley 36 of the second drive element 38 via a ball bearing set 60 and is axially fixed. The drive hub 56 of the pulley 36 of the second drive element 38 is also rotatably mounted on the output shaft 40 via a further ball bearing set 62 and is axially fixed. The internal teeth 54, 58 of the first and second drive elements 32, 38, and the external teeth 50 of the shift sleeve 46 are designed to be complementary to each other, thus ensuring a rotationally fixed connection and axial displacement. The same applies to the internal teeth 48 of the shift sleeve 46 and the external teeth 44 of the output shaft 40.In total, the transmission device 34 thus comprises three gear pairs: a first gear pair consisting of external teeth 50 of the shift sleeve 46 and internal teeth 54 of the first drive element 32; a second gear pair consisting of external teeth 50 of the shift sleeve 46 and internal teeth 58 of the second drive element 38; and a third gear pair consisting of internal teeth 48 of the shift sleeve 46 and external teeth 44 of the output shaft 40.

[0025] As mentioned above, the shift sleeve 46 can be positioned in three shift positions by axial displacement on the output shaft 40. To ensure axial fixation and correct axial positioning of the shift sleeve 46 on the output shaft 40, a first (axially inner), second (axially outer), and third (axially central) annular groove 64, 66, 68 is formed on the radial inner surface of the shift sleeve 46. Each of these grooves can be engaged with a first and a second locking pin 70, 72. The locking pins 70, 72 are guided in radial bores 74, 76 on the outside of the output shaft 40 at circumferentially opposite positions. The locking pins 70, 72 are each preloaded by a spring 78, 80. By axially displacing the shift sleeve 46 relative to the output shaft 40, the annular grooves 64, 66, 68 can be engaged with the locking bolts and the shift sleeve 46 can be fixed.For the first switching position, in which the external toothing 50 of the switching sleeve 46 is engaged in the internal toothing 54 of the first drive element 32, the switching sleeve 46 is fixed by means of the engagement position of the first annular groove 64 with the locking bolts 70, 72 (see . Figure 3 For the second switching position, in which the external toothing 50 of the switching sleeve 46 is engaged in the internal toothing 58 of the second drive element 38, the switching sleeve 46 is fixed by means of the engagement position of the second annular groove 66 with the locking bolts 70, 72 (see Figure 4 For the third switching position (neutral position), in which the external toothing 50 of the switching sleeve 46 is positioned axially between the two internal toothings 54, 58 of the first and second drive elements 32, 38, respectively, the switching sleeve 46 is fixed by means of the engagement position of the third annular groove 68 with the locking bolts 70, 72 (see Figure 2 ).

[0026] For actuation and manipulation in order to axially displace and rotate the shift sleeve 46, an actuating knob 82 is provided, which is axially fixed at the outer end (axially outside) of the shift sleeve 46 and is rotationally fixed to the shift sleeve 46. The outer end of the shift sleeve 46 (axially outside) describes the free end of the shift sleeve 46 that is not guided on the output shaft 40. An inner end of the shift sleeve 46 (axially inside) describes, accordingly, the end of the shift sleeve 46 that is guided on the output shaft 40.

[0027] The output shaft 40 is designed as a hollow shaft with further internal teeth 84 and can in turn engage with external teeth on a drive shaft (not shown) to drive the processing device 14, or other equipment or devices (not shown) for processing the harvested crop. Examples include chopping, cutting, blowing, or conveying devices, which can be driven at different speeds. This is achieved by using pulleys 30 and 36 with different diameters, thus creating different gear ratios.

[0028] As described at the beginning, when changing from one switching position to another, the external teeth 50 of the switching sleeve 46 must be engaged with the respective internal teeth 54, 58 of the first and second drive elements 32, 38 by axially displacing the switching sleeve 46. This is only possible if the teeth of the respective gears do not meet face to face. To ensure this, the switching sleeve 46 must be rotated or aligned before engagement, if necessary, so that the teeth of the external teeth 50 are guided into the tooth gaps of the respective internal teeth. To make the rotation and alignment as easy as possible, the spaces between the teeth were designed to be...The tooth gaps of the internal teeth 54 and 58 of the drive elements 32, 34, of the external teeth 50 of the shift sleeve 46, of the internal teeth 48 of the shift sleeve 46 and of the external teeth 44 of the output shaft 40 are selected such that a limited freewheel (F1, F2) (in the direction of rotation) results for the shift sleeve 46 relative to the drive elements 32, 34 or drive hubs 52, 56 and the output shaft 40 (as in . Figure 5(as shown schematically). The shift sleeve 46 can thus be aligned by at least two times a tooth width (Z1, Z2) (relative to the respective pitch circle (T1, T2) of the gear teeth) with virtually no resistance, i.e., without significant torques opposing the direction of rotation, so that sufficient free play (F1, F2) is ensured for every rotational position of the shift sleeve 46 to overcome contact between the end faces of the teeth during engagement. In other words, every possible overlap condition during a switching operation from one switching position to another (i.e., every possible misalignment during engagement) can be overcome by the free play (F1, F2). A limited free play (F1, F2) is thus created for the shift sleeve 46, which is provided in both circumferential directions depending on the rotational position of the shift sleeve 46. That is to say, the shift sleeve 46 is in every rotational position orThe switching position allows for a certain degree of rotation without any engagement of the teeth, neither on the part of the drive elements 32, 34 nor on the part of the output shaft 40, and is freely rotatable in at least one direction of rotation. The limited freewheel (F1, F2) covers approximately one arc length of the respective pitch circle (T1, T2) of twice one tooth width (Z1, Z2) on the respective pitch circle (T1, T2).

[0029] According to Figure 5The tooth spacing (A1, A2) for the respective gear pairs is dimensioned such that the first, second, and third gear pairs have a tooth pitch (pm) approximately twice the tooth pitch (p) associated with the standardized gear modules (m). This results in a tooth spacing (A1, A2) approximately twice the tooth pitch for the internal gears 54, 58 of the drive hubs 52, 56, the external gear 50 and the internal gear 48 of the shift sleeve 66, and the external gear 44 of the output shaft 40. The tooth spacing (A1, A2) is defined as the distance between two identical points of two adjacent teeth on the respective pitch circle (T1, T2). The tooth spacing (A1, A2) thus directly influences a tooth gap width (B1, B2) or tooth interspace length at the level of the respective pitch circle (T1, T2) of the gear pairing.With this type of gear design, the tooth spacing (A1, A2) in the respective gear pairs is doubled compared to a standardized gear, while the tooth geometry, i.e., the shape and size of the teeth, is maintained according to the tooth geometry assigned to the standardized tooth modules (m). The ratio of tooth gap width (B1, B2) or tooth gap length to tooth width (Z1, Z2) at the level of the respective pitch circle (T1, T2) is thereby approximately tripled (from approximately 1 (for a single tooth gap) to approximately 3 (for a triple tooth gap)). In other words, the gear pairs according to the invention between shift sleeve 46 and drive elements 32, 34 or between shift sleeve 46 and output shaft 40 are designed with only every second tooth compared to a standardized gear pair. Or, conversely, the gear pairs in... Figure 5The depicted gear pairings are thus maintained or designed in such a way that only every second tooth is provided in the standardized gear pairing with standardized tooth modules (m). This approximately triples the available clearance (tooth gap widths (B1, B2) or tooth interspace lengths) for the inset of the teeth. The tooth pitch (p) which is approximately twice as large (compared to a tooth pitch (pm) assigned according to standardized tooth modules (m)) is applied both to the two gear pairs on the outside of the shift sleeve 46 (internal teeth 54, 58 of the drive hubs 52, 56 with the external teeth 50 of the shift sleeve 46) and to the third gear pair on the inside of the shift sleeve 46 (internal teeth 48 of the shift sleeve 46 with the external teeth 44 of the output shaft 40), so that the tooth spacing (A1, A2) (relative to the respective pitch circle (T1, T2)) is also the same there.at the height of the pitch circle (T1, T2)) from approximately one tooth width (Z1, Z2) according to the standard to approximately three times one tooth width (Z1, Z2) according to . Figure 5 is enlarged.

Claims

1. Transmission device (34) having a first drive input element (32), a second drive input element (38), a shift sleeve (46) configured as a hollow shaft, and a drive output shaft (40), wherein the shift sleeve (46) is mounted axially displaceably on the drive output shaft (40) and can be moved by axial displacement into a first, a second or a third shift position, an internal toothing (54, 58) is formed on each of the first and the second drive input element (32, 38), an external toothing (50) and an internal toothing (48) are formed on the shift sleeve (46), and an external toothing (44) is formed on the drive output shaft (40), wherein, in the first shift position, the external toothing (50) of the shift sleeve (46) forms a first toothing pairing with the internal toothing (54) of the first drive input element (32), in the second shift position, the external toothing (50) of the shift sleeve (46) forms a second toothing pairing with the internal toothing (58) of the second drive input element (38), and the internal toothing (48) of the shift sleeve (46) forms a third toothing pairing with the external toothing (44) of the drive output shaft (40), characterized in that the first, second and third toothing pairing are configured with a tooth pitch (p) which is greater by approximately a factor of 2 than a tooth pitch (pm) associated with standardized toothed gear moduli (m), such that a tooth spacing (A1, A2) that is greater by approximately a factor of 2 is achieved.

2. Transmission device (34) according to Claim 1, wherein multiple annular grooves (64, 66, 68) are formed on the inside of the shift sleeve (46), and one annular groove (64, 66, 68) is assigned to each shift position, which annular grooves can in each case be placed in engagement, by axial displacement of the shift sleeve (46) on the drive output shaft (40), with at least one detent bolt (70, 72) that is mounted in spring-preloaded fashion in the drive output shaft (40).

3. Transmission device (34) according to Claim 1 or 2, wherein, on one axial end of the shift sleeve (46), there is formed an actuating boss (82) for the axial adjustment and rotational alignment of the shift sleeve (46).

4. Transmission device (34) according to any one of Claims 1 to 3, wherein the drive output shaft (40) is configured as a hollow shaft and has an internal toothing (84).

5. Transmission device (34) according to any one of Claims 1 to 4, wherein the transmission device (34) is configured as a belt drive transmission, and the first and the second drive input element (32, 38) comprise a pulley (30, 36).

6. Agricultural harvesting machine (10) having a belt drive (20) and having a transmission device (34) according to one or more of Claims 1 to 5 assigned to the belt drive (20) .