TRANSMISSION WITH NON-COAXIAL OUTPUT
According to the preamble of claim 1 the Invention relates to a transmission having a main shaft and a countershaft.
From the prior art, transmissions are already known having one input shaft, one main shaft, one countershaft and one output shaft in which in the input shaft, the main shaft and the output shaft are mounted on a common axis of rotation. Transmissions of this kind can have a one piece input and output shaft or a one piece main and output shaft. A transmission of this kind is shown, e.g. in DE 195 38 192.
The numbers of teeth on the gear wheels of the shafts are determined on the basis of the desired reduction ratios. This implies specific diameter ratios of the gearwheels of the parallel shafts relative to each other and thus also the spatial distance between the shafts. Thus the gear wheel pair consisting of the first gear wheel upon the input shaft and the first gear wheel upon the countrshaft, seen from the input side, are configured so that a gear wheel of very small diameter upon the input shaft is associated with a gearwheel of very large diameter upon the countershaft. This pair of gear wheels makes a transmission of a great torque to a lower speed level possible, but a great spatial distance results in a large size of the transmission housing which can lead to difficulties in the installation space for the vehicle manufacturer.
The problem on which the invention is based is to reduce the installation space needed for a transmission and lead to a smaller size of the transmission.
The problem is solved by a transmission having the features of claim 1. Developments are object of sub-claims.
It is proposed, according to the invention, to non-rotationally mount upon the output shaft of the transmission a gear wheel which is driven by a gear wheel non-rotationally connected with the countershaft the gear wheel pair forming one constant. The input shaft of the transmission is non-rotationally connected with the main shaft. The axis of rotation of the

input shaft and the axis of rotation of the main shaft are equal and the axis or rotation of the main shaft and the axis of rotation of the output shaft do not form the same axis. The distance between the axes of rotation of main shaft and output shaft is determined by the reduction ratio of the gear wheel pair of the constant
In an advantageous development, thegear wheel pairof the constant Is lodged In a separate transmission housing in order to make a replacement of the gear wheel pair possible.
In another advantageous development for driving a hydrodynamic retarder, an auxiliary output shaft is provided which can be driven directly by the main shaft or the countershaft and serves to achieve a high rotational speed pf the retarder without Intercalation of a high driving step.
An advantageous development shows upon the output shaft a gear shift device for a splitter transmission to subdivide the gear steps in half speed steps.
In an advantageous development a range-change group transmission, in the form of a pianeta/ytransmission, is provided next to trie gear wheel pair of the constant for enlarging the total spreading of the transmission.
By shifting the arrangement of a constant of the transmission to the output side end of the transmission and the non-coaxialrty of the axes of rotation of main shaft and output shaft, the diameters of the large wheel of the transmission are reduced. Thereby, with reduced diameters, the weight of the gear wheels can be reduced and the axial distances of the parallel shafts shortened, which results in a smaller size for the transmission. A reduced size of the transmission means in this place advantageously (ess weight and more installation space In the vehicle. At the same time, less expenditure in material and processing for smaller gearwheels and housing results In lower cost The smaller masses of the gear wheels to move and synchronize, when shifting, result In a level of shifting effort clearly below the level already known in conventional transmissions. The synchronizing

devices also are less apt to fail, since the masses to be synchronized are smaller. By virtue of the smaller gear wheels on the input-side end of the countershaft with a small axial distance between input shaft and main shaft and the countershaft, the rotational speeds of the countershaft are at a higher level. Thereby a reduced torque level, on which the structural pans of the transmission must be designed, is obtained in the largest part of the transmission. A high torque only generates in the output constant when an enlarged axial distance exists between the output shaft and the countershaft. With the inventive arrangement, the transmission input torque can be designed the same size for transmission constructions having direct drive and cWdrive versions.
As a result of a one piece design of the input shaft and the main shaft, the pivot bearing 4 of the main shaft and the input shaft of the prior art can be eliminated. The gear wheel pair mounted on the transmission end can be configured so as to be inserted as a separate unit, after the other transmission housing, making a modular design of transmissions having different wheel pairs on the output constant nrwRihte.
The invention Is described in detaB with reference to drawings wherein*.
Fig. 1 is a transmission according to the prior art;
Fig, 2 is a diagrammatic arrangement of a transmission according to the invention; and
Fig. 3 is an arrangement according to Fig. 2 with splitter transmission.
Fig. 1 shows an enlarged illustration of a transmission 6 according to the prior art having, e.g. five forward gears and one reverse gear. With a control lever 18 access is had to the three gearshift rods 20, 22 and 24 which, via gear shift forks, move the synchronizing devices 26.28 and 30 to the desired gear shift positions. Thus the synchronizing device 30 engages the reverse gear and the first transmission ratio. The synchronizing device 26 engages the gear steps two and three while the synchronizing device 28 is used to engage the gear steps four and five. The input shaft 32

fs supported in the transmission housing 34 by a support such as the bearing 36 shown here. The main shaft 38 is supported in the transmission input shaft 32 by a bearing 40 and in the housing 34 by a support such as a bearing 42 shown here. The reverse direction of rotation for the reverse gear is obtained by an intermediate gear 44 the toothing of which meshes with the toothing of the reverse gearwheel upon the main shaft 38 and the toothing of the countershaft 46. The other toothings of the gear wheels, on the main shaft 38, likewise engage for the forward gear ratio in .corresponding toothings of the countershaft 48. A toothing for mounting a dutch body 54 is additionally provided on the transmission input 32.
Rg. 2'shows a diagrammatic illustration of the transmission constructions according to the invention. A transmission 60 has a housing 62 in which an input shaft 64 projects. The input shaft 64 is designed integral with the main shaft 66 of the transmission 60. On the main shaft 66 seven gear wheels 68,70,72,74,76,78,80 are mounted of which the gear wheels 68, 70, 72, 74 can loosely rotate upon the main shaft 66 while the gear wheels 76,78,80 are permanently non-rotationally connected with the main shaft 66. A synchronizing device 82 is provided between the gear wheels 68 and 70 by which the gear wheel 68 or the gear wheet 70 can be optionally non-rotationally connected with the main shaft 66. A synchronizing device 84 is provided between the gear wheels 72 and 74 by which the gearwheel 72 or the gear wheet 74 can be optionally non-rotationally connected with the main shaft 66.
Seven gear wheels 88,90,92,94,96,98,100 are likewise provided upon the countershaft 86 of which the gear wheels 88, 90, 92, 94 are permanently non-rotationally connected with the countershaft 86. A synchronizing device 102 is provided between the gearwheels 96 and 98 by which the gear wheel 96 or the gear wheel 98 can be optionally non-rotationally connected with the countershaft 86. The gear wheel 100 meshes for reverse direction of rotation for the reverse gear with an intermediate gear 104 which, In turn, meshes with the gear wheel 80 upon

the main shaft 66. The gear wheel 98 meshes with a gear wheel 120 upon an auxiliary output shaft 122 by which a retarder 124 is driven. Due to the large diameter of the gear wheel 98, the auxiliary output shaft 122 is driven at a high rotational speed.
In the illustration shown here, one other housing 106 is provided next to the transmission housing 62. A gear wheel pair consisting of two gear wheels 108 and 110 is mounted in the housing 106, the gearwheel 108 is non-rotationaHy connected with the countershaft 86. The gear wheel 110 is permanently non-rotationally connected with the output shaft 112, but the gear wheels 108 and 110 can also be situated within an adequately configured transmission housing 62. Gearwheel 110 and output shaft 112 rotate around an imaginary axis of rotation 114. The main shaft 66 and the gearwheels mounted thereon, the same as the input shaft 64, rotate around an axis of rotation 116. Both axes of rotation 114 and 116 are not coaxial with respect to each other, but are separated by an axial distance 118.
Rg. 3 shows an enlarged arrangement in comparison with that of Fig. 2 with a splitter transmission 134 in the housing 106 to form a second constant. A synchronizing device 126 is provided upon the output shaft 112 by which the gear wheel 111 or the gear wheel 128 can be optionally non-rotationalry connected with the output shaft. The gear wheel 108 is non-rotattonaliy situated Jointly with a gearwheel 130 upon a shaft 132.

Claims
1. Vehicle transmission (6,60) having one input shaft (32.64), one main shaft (38,66), one countershaft (46, 86} and one output shaft (112) which are rotataWy mounted around axes of rotation (114,116) and having a plurality of loose (68, 70. 72,74,96, 98,111,128) and fixed (76, 78,80, 88,90,92,94.108,110,130) gearwheels mounted on the shaft (32,38,46, 60,64,66,112,132), characterized In that upon said output shaft (112) is non-rotatauiy mounted a gear wheel (110, 111, 128) driven by a gear wheel (108, 130} non-rotationafty connected with said countershaft (86) wherein said gear wheel pair (108-110,108-111,130-128) forms a constant, said input shaft (84) of said transmission (60) is non-rotationafly connected with said main shaft (66), the axis of rotation (116) of said input shaft (64) and the axis of rotation (116) of said main shaft (66) forming one and the same axis and that said axis of rotation (114) of said output shaft (112) do not form the same axis and the distance (118) between said axes of rotation (114,116) of main shaft (66) and output shaft (112) is determined by the reduction ratio of said gearwheel pair (108-110,108-111,130-128} of said constant
2. Vehicle transmission (S, 60) according to claim 1, characterized in that said gear wheel pair (108-110,108-111,130-128) of said constant is lodged in a separate transmission housing (106) to make possible a replacement of said gearwheel pair (108-110,106-111,130-128).
3. Vehicle transmission (6, 60) according to claim 1 or 2,
characterized in that for driving a hydrodynamlc retarder (124) an auxiliary
output shaft (122) is provided which can be directly driven by said main
shaft (66) or said countershaft (88) to achieve a high rotational speed of said
retarder (124) without intercalation of a high driving step.
4. Vehicle transmission (6, 60) according to any one of claims 1 to 3, characterized in that upon said output shaft (112) a synchronizing

device (126) for a splitter transmission (134) is provided to subdivide the gear steps In hatf gear steps.
5. Vehicle transmission (6, $0) according to any one of claims 1 to 3. characterized in that next to said gearwheel pair {108-110,108-111, 130-126) a range group transmission in the form of a planetary transmission Is provided to enlarge the total spread of said transmission (60).

6. Vehicle transmission substantially as herein described with reference to the accompanying drawings.