Search

EP-4474677-B1 - TRANSMISSION DEVICE AND AGRICULTURAL MACHINE WITH SUCH A TRANSMISSION DEVICE

EP4474677B1EP 4474677 B1EP4474677 B1EP 4474677B1EP-4474677-B1

Inventors

  • Rohlfing, Thomas
  • JUNDALE, Prashant M
  • Perez, Javier Jose

Dates

Publication Date
20260513
Application Date
20230605

Claims (6)

  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) .

Description

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. Gearboxes and drive devices with gearboxes for driven processing equipment on harvesting machines are known and are used in various forms and in a wide range of applications. For example, the DE 2 745 564 C2 A drive device for a processing unit of a combine harvester, comprising 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 to a gear of opposite rotation, connected to the drive gear. In a first position, the switching element connects a sun gear of a planetary gear set to the main drive shaft via planet gears and a second sun gear set. In a second position, the sun gear of the planetary gear set connects to the main drive shaft via planet gears and a ring gear carrier. The DE 2 744 344 C3 The document 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, via an optionally engageable reduction gear, to an output shaft, for example, to an output shaft for a threshing drum. 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 used in DE 102019213717 A1 The transmission device comprises a switching 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 switching 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. 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. 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). They can also be used to drive blower systems in harvesting machines. The aforementioned belt drives with two pulleys are used. 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 branched off v