Powershift transmission for agricultural machines

Abstract

A powershift transmission for an agricultural machine includes a transmission housing, an input shaft unit and an output shaft, wherein the input shaft unit and the output shaft extend at least in sections within the transmission housing. An auxiliary shaft is arranged parallel to but offset between the input shaft unit and the output shaft. The input shaft unit and the auxiliary shaft are connected to one another via a front-mounted range unit, and the auxiliary shaft and the output shaft are connected to one another via a rear-mounted range unit. The front-mounted and rear mounted range units each includes at least two gear wheel pairs, the at least two gear wheel pairs being individually coupled or decoupled. The auxiliary shaft unit includes a first auxiliary shaft and a second auxiliary shaft, where the first and second auxiliary shafts are coupled to one another via a reduction gear unit.

Claims

1. A powershift transmission for an agricultural machine, comprising: an input shaft; an output shaft arranged parallel and offset to the input shaft; a first auxiliary shaft arranged next to and coaxial with a second auxiliary shaft, the first and second auxiliary shafts arranged parallel and offset between the input shaft and the output shaft; a front-mounted range unit including four individual gear wheel pairs connecting the input shaft and the first auxiliary shaft, the four individual gear wheel pairs being coupled or decoupled via a first plurality of clutches having two clutches arranged on the input shaft and two clutches arranged on the first auxiliary shaft, the front-mounted range unit including four shifted states; a reduction gear unit connecting the first auxiliary shaft and the second auxiliary shaft, the reduction gear unit including a first reduction-gear-unit gear wheel pair and a second reduction-gear-unit gear wheel pair; and a rear-mounted range unit including four individual gear wheel pairs connecting the second auxiliary shaft and the output shaft, the four individual gear wheel pairs being coupled or decoupled via a second plurality of clutches having two clutches arranged on the second auxiliary shaft and two clutches arranged on the output shaft, the rear-mounted range unit including four shifted states; wherein in a first shifted state of the reduction gear unit, the first auxiliary shaft is coupled directly to the second auxiliary shaft so that both transmitted torque and rotational speed remain unchanged between the first auxiliary shaft and the second auxiliary shaft; wherein in a second shifted state of the reduction gear unit, the first auxiliary shaft is connected to the second auxiliary shaft via the first reduction-gear-unit gear wheel pair and the second reduction-gear-unit gear wheel pair so that transmitted torque increases and rotational speed decreases; wherein in the first shifted state and the second shifted state of the reduction gear unit, the input shaft and the output shaft rotate in a first direction, and the first auxiliary shaft and the second auxiliary shaft rotate in a second direction opposite the first direction; wherein the front-mounted range unit defines a first shift level, the reduction gear unit defines a second shift level arranged downstream of the first shift level, and the rear-mounted range unit defines a third shift level arranged downstream of the second shift level; and wherein the powershift transmission includes thirty-two gearshift variants.

2. The powershift transmission of claim 1, wherein the rotational direction of the main output shaft is reversible by a reversing unit.

3. The powershift transmission of claim 2, wherein the reversing unit is integrated into the reduction gear unit.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The above-mentioned aspects of the present disclosure and the manner of obtaining them will become more apparent and the disclosure itself will be better understood by reference to the following description of the embodiments of the disclosure, taken in conjunction with the accompanying drawings, wherein:

(2) FIG. 1 shows a schematic illustration of an agricultural working machine,

(3) FIG. 2 shows a powershift transmission according to the disclosure with 32 gearshift variants,

(4) FIG. 3 shows an alternative embodiment of the powershift transmission according to FIG. 2, and

(5) FIG. 4 shows a shifting principle of the powershift transmission according to the disclosure.

(6) Corresponding reference numerals are used to indicate corresponding parts throughout the several views.

DETAILED DESCRIPTION

(7) The embodiments of the present disclosure described below are not intended to be exhaustive or to limit the disclosure to the precise forms disclosed in the following detailed description. Rather, the embodiments are chosen and described so that others skilled in the art may appreciate and understand the principles and practices of the present disclosure.

(8) FIG. 1 shows an agricultural working machine in the form of a tractor 10 and any desired implement 12 which is towed by the tractor and is embodied as a round bale press, for example, in the illustrated embodiment. The implement 12 comprises a chassis 14 which is supported on wheels 16 and has a bale-forming chamber 18. The implement 12 is towed by the tractor 10 by means of a drawbar 20. The driveable elements of the drawbar 20 are driven by the tractor 10 by a power take-off shaft 22.

(9) The tractor 10 comprises a chassis 24 which is supported on front, steerable wheels 26 and driven wheels 28 at the rear. An operator workstation with a seat 32 is located in a cab 30. A steering wheel 34, an accelerator pedal 36 and an operator position 38 can be activated from the seat.

(10) FIG. 2 shows a schematic diagram of the powershift transmission according to the present disclosure. The powershift transmission has an input shaft 41 and an output shaft 61, wherein an auxiliary shaft unit composed of a first auxiliary shaft 51 and a second auxiliary shaft 52 is arranged with a parallel offset between the input shaft 41 and the output shaft 61. A drive machine 49, which transmits a torque to the input shaft 41, is provided on the input shaft 41. This torque is transmitted by the input shaft 41 to the auxiliary shaft unit via a front-mounted range unit 40, wherein in turn a transmission of torque takes place between the auxiliary shaft unit and the output shaft 61 via the rear-mounted range unit 60.

(11) In the embodiment which is shown by way of example, the front-mounted range unit 40 has a total of four gear wheel pairs I, II, III, IV, each composed of a drive gear wheel 42 and an output gear wheel 43, which can be engaged with one another via a clutch 44. These four gear wheel pairs I, II, III, IV are distinguished by different transmission ratios. For example, the gear wheel pair I has a relatively small drive gear wheel 42 and a large output gear wheel 43. As long as these gear wheels are in engagement with one another, the rotational speed of the output gear wheel 43 is reduced and at the same time the torque is increased. In comparison with this, the gear wheel pair IV has a relatively large drive gear wheel 42 and a relatively small output gear wheel 43, as a result of which the rotational speed of the output gear wheel 43 is increased and the torque is reduced.

(12) In order to transmit the torque from the input shaft 41 to the auxiliary shaft unit, the drive gear wheels 42 of the front-mounted range unit 40 are arranged on the input shaft 41, and the output gear wheels 43 are arranged on the first auxiliary shaft 51. In each case, two of the clutches 44 of the gear wheel pairs I, II, III, IV are in this case arranged on the input shaft 41 and the other two clutches 44 are arranged on the first auxiliary shaft 51. As a result, the installation space can be kept as small as possible in the direction of the axis of rotation of the input shaft 41 and the first auxiliary shaft 51. However, embodiments are also possible in which all of the clutches 44 are arranged exclusively on the input shaft 41 or on the first auxiliary shaft 51.

(13) Arranged between the first auxiliary shaft 51 and the second auxiliary shaft 52 is a reduction gear unit 50, via which the first auxiliary shaft 51 is connected to the second auxiliary shaft 52. The reduction gear unit 50 has a clutch Hi, via which the first auxiliary shaft 51 can be directly coupled to the second auxiliary shaft 52. For this purpose, the two auxiliary shafts 51, 52 are arranged one next to the other and coaxially with respect to one another, wherein the clutch Hi permits direct transmission of the torque, so that both the transmitted torque and the rotational speed remain unchanged after engagement of the clutch. Such a connection constitutes a first shifted state of the reduction gear unit 50, which state describes a high load state.

(14) In a second shifted state of the reduction gear unit 50, the first auxiliary shaft 51 is connected to the second auxiliary shaft 52 via a first and a second reduction-gear-unit gear wheel pair 53, 54. There, the output gear wheel of the first reduction-gear-unit gear wheel pair 53 can be coupled to the drive gear wheel of the second reduction-gear-unit gear wheel pair 54 via a clutch Lo. The drive gear wheel of the first reduction-gear-unit gear wheel pair 53 is arranged here on the first auxiliary shaft 51, and the output gear wheel of the second reduction-gear-unit gear wheel pair 54 is arranged on the second auxiliary shaft 52. Both reduction-gear-unit gear wheel pairs 53, 54 are embodied here in such a way that a transmission, that is to say a reduction of the rotational speed and an increase in the torque, takes place. The second shifted state defines a low load state.

(15) Irrespective of the shifted state of the reduction gear unit 50, the auxiliary shafts 51, 52 always have the same direction of rotation, which is reversed in comparison with the input shaft 41.

(16) The transmission of the torque from the auxiliary shaft unit to the output shaft 61 takes place via a rear-mounted range unit 60. For this purpose, the drive gear wheels 62 are arranged on the second auxiliary shaft 52, and the output gear wheels 63 are arranged on the output shaft 61.

(17) The rear-mounted range unit 60 also has four gear wheel pairs A, B, C, D. The number of gearshift variants results now from a multiplication of the gear wheel pairs of the front-mounted range unit 40, of the rear-mounted range unit 60 and the shifted states of the reduction gear unit 50. Therefore, a total of 32 gears can be implemented. Removing, for example, the gear wheel pair IV and the gear wheel pair D causes the number of gearshift variants to be reduced to only 18.

(18) The individual gear wheel pairs A, B, C, D of the rear-mounted range unit 60 can also be coupled and decoupled via respectively assigned clutches 64, wherein in the example shown two of the clutches 64 are arranged on the second auxiliary shaft 52 and the other two clutches 64 are arranged on the output shaft 61. Here, too, the clutches 64 can be arranged exclusively on the second auxiliary shaft or the output shaft 61.

(19) Moreover, the powershift transmission has a reversing unit 70 which is integrated into the reduction gear unit 50.

(20) FIG. 3 shows an alternative embodiment of the powershift transmission according to FIG. 2, which differs in the embodiment of the reduction gear unit 50. In contrast to FIG. 2, the auxiliary shafts 51, 52 cannot be coupled directly to one another. Instead, a first shifted state is implemented by means of the first reduction-gear-unit gear wheel pair 53, and a second shifted state is implemented by the second reduction-gear-unit gear wheel pair 54. The first reduction-gear-unit gear wheel pair 53 can be coupled in here by means of the clutch Lo and defines a low load state, while the second reduction-gear-unit gear wheel pair 54 is coupled by means of the clutch Hi and defines a high load state. The other components are embodied in a way analogous to the powershift transmission according to FIG. 2. In particular, the front-mounted range unit 40 also has four gear wheel pairs I, II, III, IV here, and also the rear-mounted range unit 60 has four gear wheel pairs A, B, C, D.

(21) The essential difference with respect to the powershift transmission according to FIG. 2 is that a reversal of the direction of rotation takes place between the first auxiliary shaft 51 and the second auxiliary shaft 52. Overall, a reversal of the direction of rotation takes place via the front-mounted range unit 40, via the reduction gear unit 50 and via the rear-mounted range unit 60, so that the output shaft 61 has a direction of rotation which is reversed in comparison with the input shaft 41. In one embodiment according to FIG. 2, the input shaft 41 and the output shaft 61 have the same direction of rotation.

(22) FIG. 4 shows a shift principle of the powershift transmission. It is shown how the powershift transmission is to run through, in order to be able to change over as continuously as possible from a low gearshift variant into a high gearshift variant. In this context, the front-mounted range unit 40 forms a first shift level, the reduction gear unit 50 forms a second shift level, and the rear-mounted range unit 60 forms a third shift level.

(23) At first, the front-mounted range unit 40 is shifted onto the gear wheel pair I, the reduction gear unit 50 is shifted into the shifted state Lo, and the rear-mounted range unit 60 is shifted onto the gear wheel pair A. In order to increase the gear, the reduction gear unit 50 is now placed firstly in the shifted state Hi, while both the front-mounted range unit 40 and the rear-mounted range unit 60 remain unchanged. In order to bring about a further increase, this operation is then repeated in the case of a successively shifted increase in the front-mounted range unit 40, until all the gear wheel pairs I, II, III, IV of the front-mounted range unit 40 have been run through.

(24) In a further step, the gear wheel pairs A, B, C, D of the rear-mounted range unit 60 are shifted through successively, wherein the shifting principle explained above is repeated for each gear wheel pair A, B, C, D of the rear-mounted range unit 60.

(25) While embodiments incorporating the principles of the present disclosure have been disclosed hereinabove, the present disclosure is not limited to the disclosed embodiments. Instead, this application is intended to cover any variations, uses, or adaptations of the disclosure using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this disclosure pertains and which fall within the limits of the appended claims.