FR2516623A1 - IMPROVED GEARBOX FOR MOTOR VEHICLE - Google Patents

Abstract

THIS AUTOMOTIVE VEHICLE GEARBOX HAS A VERY SLOW GEAR WHICH THE REDUCTION IS GREATER THAN THAT OF THE FIRST GEAR OF THE GEARBOX. THE BOX INCLUDES A MAIN DRIVE SHAFT 2 HAVING A MAIN PART 2A AND AN EXTENSION 2B AND A MAIN GEAR CHANGE DEVICE IS PROVIDED ON THE SAID MAIN PART 2A OF THE SHAFT. VERY SLOW RATIO DEVICE IS PROVIDED ON EXTENSION 2B. TO CREATE SUCH A HIGH REDUCTION RATIO, THE DIAMETER OF THE EXTENSION 2B OF THE MAIN SHAFT 2 IS REDUCED AND A VERY SLOW RATIO DRIVE PINION 30 IS SHAPED ON THE SAID PART 2B OF REDUCED DIAMETER. THIS PART 2B IS SUPPORTED BY TWO BEARINGS 14, 15 AT ITS TWO ENDS IN ORDER TO KEEP PART 2B OF THE SHAFT'S REDUCED DIAMETER THE RESISTANCE NECESSARY TO SUPPORT THE LOAD IMPOSED BY THE DEVICE AT VERY SLOW RATIO.

Description

The present invention relates to a gearbox for a

  motor vehicle such as a vehicle

  four-wheel drive or truck In such a vehicle

  As a matter of course, it is desirable to provide a ratio with a large reduction or very slow relief ratio, which presents a reduction ratio greater than that of the first

  gearbox report to provide a couple of drives

  high for transporting a heavy load or climbing a steep slope There are, however, difficulties in achieving a gearbox with such a

  very slow relationship as will be described below.

  To achieve a high gear ratio, a drive gear for the very slow ratio must have a very large number of teeth, which means that

  diarnetre of pi-non of drive must be considerable-

  El reduced is preferable to form the pinion of-

  training on a training area of one box

  classic vit-esses, in an extension The pro-

  along the drive shaft must have a cross-piece

  be very small to be able to form such a small drive pinion Furthermore, the drive shaft has the inevitable united way elongated bearing between the bearings Consequently if such a part of putit diameter G is formed in a part of the drive shaft with a longer reach than in conventional gearboxes, the resistance of the drive shaft decreases to a too low value

to support the desired load.

  Furthermore in such a vehicle it is desired to

  ble auglenier the reduction ratio of a reverse gear has a value roughly equal to that of the slow ratio, from the point of view of the yield of the

  vehicle To achieve such a great demulti-

  plication rour the rear step, there must be a

  large idler gear and a large driven gear It is however

  difficult to incorporate such large gears in the housing of a gearbox of a single construction

  analogous to the housing of conventional boxes.

  The object of the invention is to provide a gearbox in which are arranged side by side a

  very slow ratio gear and a reverse gear

  first and in: watercolor drive sprockets for the two aforementioned ratios can be formed on a

  gearbox drive shaft without reducing the resistance

L oance of this arore.

  According to the invention, a vehicle gearbox comprises a main drive shaft having a main part and an extension, and a

  deflection shaft arranged parallel to the main shaft

  pal A main gear change device is provided on the main part of the main drive shaft and a very slow gear device is provided on the extension of the shaft The very slow gear device has a gear ratio reduction which is greater than that of a first report of the main gearshift device To produce a

  such a high reduction ratio, the diameter of the prolon-

  genent of the main shaft is reduced and a drive pinion for the very slow ratio db pinion is formed on the part of reduced diameter This part of reduced diameter is carried by two bearings at both

  ends to keep the resistamce ne-

stop.

  Other features and advantages of the invention

  tion will appear during the description which goes

  follow, made with reference to the annexed drawings given only as examples and in which:

  Fig l is a sectional view of a box of vi-

  braids according to the invention; Fig 2 is a sectional view along line II-I of Fig l;

  Fig 3 is moult view showing a changing grid

  report of a selection lever.

  Fig l shows an embodiment of the invention

  tion which is applied to um four-wheeled vehicle mo-

  trices. Referring to F'ig l, a crankshaft 1 of an engine (not shown) which is mounted transversely

  in a rear part of a four-wheeled motor vehicle

  three wheel drive can be selectively connected to a main drive shaft 2 of a gearbox 3 via a clutch 4 The gearbox 3 is arranged aligned with the crankshaft 1 of the engine The gearbox outlet is transmitted to the front wheels by

  the in ermc-diary of a final reducer 5 and a device

  transfer tif 6 as will be described below.

  A gearbox housing for the gearbox 3 comprises a main part 7 fixed on a clutch housing 8 and a rear part 10 fixed on the main housing 7 at the rear end thereof. The main housing 7 is construction similar to a conventional four-speed gearbox housing In the main part 7 esc arranged a main gear 11 of gear ratio comprising first, second, third and fourth gear gears and, in the rear part l O of housing is arranged a device 12 comprising a reverse gear and a very slow gear The main drive shaft 2 of the gearbox 3 is extended through the casings 8, 7 and l O and mounted rctatif by bearings 13, 14 and 15 which are provided in the rear side walls 8 a, 7 a and l Oa of the casings 8, 7 and 10 respectively A deflection shaft 9 is arranged parallel to the main shaft 2 and carried by bearings 16, 17 and 18 The main arore 2

  has a main part 2 a in the main casing

  pal 7 On the main part 2 a are formed a

  drive gear 19 first gear, a pinion

  drive 20 of second gear, a drive pinion

  third gear 21 and a drive gear

  ment 22 of fourth gear Pinions driven 23, 24, and 26 are rotatably mounted on the idler shaft 9 and cooperate respectively with the pinions 19 to 22.

  r: between the gables 23 and z 4 is provided a first arrangement

  tif synchronizer 27 for coupling pinion 23 or 24

  to the return shaft 9 for the first and second reports

  ports' A second synchronizing device 28 is provided in an analogous manner between the pinions ú 5 and 26 for

  the third and fourth reports.

  According to the invention the main drive shaft

  nement 2 compowte an extension 2 b in the casing

  rear 10 the extension 2 b of the main shaft pre-

  feels a small diameter for the devices 12 reverse and slow ratio and a pinion 29 reverse and a pinion 30 very slow ratio are formed on this part 2 b of the shaft The drive pinion 29 reverse gear comprises a number of teeth smaller than the first gear drive pinion 19

  and the reverse drive pinion 29 comprises

  te also a small number of teeth which is approxima-

  tively equal to that of the pinion leading 30 The reduction ratios of the two gears of very slow ratio and

  reverse are almost equal to each other

  tre The drive pinion 30 cooperates with a pinion

  driven 31 rotates on the shaft 9 and the drive pinion

  reverse gear 29 cooperates with a idler gear 33 A synchronizing device 32 is mounted on

  shaft 9 for the very slow ratio the syn-

  chroniser 32 comprises a sleeve 32 a which comprises a driven pinion 34 of reverse gear When the sleeve 32 a is moved to the left, the pinion 34 cooperates with the idler pinion 33 meshing with the drive pinion 29

reverse gear.

  The first gear 23, the third gear 25 and the reverse gear 29 are

  arranged on the right side of the synchronizing devices

  sors 27, 28 and 32, and a gear 24 of second gear, a gear 26 of fourth gear and a gear 31 of very slow gear are arranged on the opposite side res-

  pectively The passage grid for a change lever

  report (not shown) for the passage of these

  reports is shown in Fig 3.

  The final reducer 5 comprises a pinion 36 of final reducer which cooperates with an output pinion 35

  formed on an end part of the return shaft 9.

  The pinion 36 is mounted on a housing 37 has a different

  tiel 37 This differential 37 is in training link

with rear axles 38.

  The final gear pinion 36 cooperates with a pinion 40 of the transfer device 6 The pinion 40 is rotatably mounted on a shaft 39 mounted transversely and carried by bearings at its two ends This transfer device 6 comprises a clutch 41 for coupling the pinion 40 on the shaft 39 A corner pinion 42 is wedged on the shaft 39 at one end thereof and cooperates with a corner pinion 43 fixed on a shaft

  drive 44 of the front wheels which is arranged longi-

  tudinally along the longitudinal axis of the vehicle and

  in drive link with the front wheels by the

  differential differential (not shown).

  In operation, the outlet of the box 3 at the

  output pin 35 is transmitted to the rear wheels via the pinion 36, the differential 37 and the axles 38 When the clutch 41 is engaged with the pinion 40, the output is also transmitted to the front wheels via of the shaft 39, of the angle gears 42, 43 and of the shaft 44 to establish the drive in four-wheel drive mode When the sleeve 32 has synchronizer device 32 is moved to the right by actuation of the change lever

  report, the manckon cooperates with the pinion leads 31.

  The vehicle can thus be driven in very slow gear.

  When the sleeve 32a is moved to the left, the pinion 34 cooperates with the idler gear 33 to establish the rear axle ratio. According to the invention, the fact that the extension of the shaft for the very slow ratio is supported by

  bearings at both ends, the reach of the extension

  ment of the drive shaft can be reduced so as to support a heavy load in the very slow gear In addition, the rear case for the very slow gear is independent of the main case of the gearbox Therefore the device except very slow gear and reverse gear can be mounted with the elements of a conventional assembly and the rear housing can be constructed appropriately to allow the mounting of the

  very slow and reverse gear.

Claims (3)

CLAIMS -   1 gearbox for vehicle characterized by   what it includes a clutch (4) in connection with   drag with an output shaft of a vehicle engine   le, a main drive shaft having a main part (2 a) and an extension (2 b) adapted to be   selectively connected to said output shaft via the   clutch medium (4), a deflection shaft (9) parallel to the main shaft (2), a clutch housing (8) enclosing said clutch (4), a main casing (7) adjacent to said clutch housing (8)   to accommodate the main part (2 a) of said tree of Ven-   main drive (2), a rear casing (7 a) adjacent to said main casing to accommodate the extension (2 b) of said drive shaft (2), a main device   of change of report planned on said main part   main shaft blade (2), a very slow ratio device provided on the extension (2b), this very slow ratio device having a reduction ratio greater than that of a first gearbox ratio, a reverse gear device p provided on the extension (2b) and adjacent to the gear device   very slow, each of these devices comprising a   drive pin (19-22, 29, 30) on said main shaft (2) and a driven pinion (23-26, 31, 34) on said idler shaft and bearings (13, 14) to support   by rotation said main part (2 a) and rolls   elements (14, 15) to support the two ends of said extension (2 b), the latter having a smaller diameter than that of the main part (2 a) to establish a high reduction ratio.   2 gearbox according to claim 1, characterized in that said main shaft (2) are aligned with said output shaft, drive pinions (19-22, 29, 30) being formed on said main tree.   3 gearbox according to claim 1, characterized in that said bearings (13, 14, 15) are arranged in a first position between the housing (8) of the towing (4) and the main housing (7) , in a second position between the main casing (7) and the rear casing (7 a) and in the third position   in a rear part of the rear casing (7 a).