FR2459917A1 - GEAR TRAIN FOR OVERMULTIPLIED SPEED IN A FOUR-WHEEL MOTOR VEHICLE - Google Patents

Abstract

THE INVENTION RELATES TO A GEAR TRAIN FOR OVERDRIVE SPEED IN A FOUR WHEEL MOTOR VEHICLE. THE GEAR TRAIN ESSENTIALLY INCLUDES A DIRECT DRIVE GEAR AND TWO OVERDRIVE GEAR GEARS, OF DIFFERENT DIAMETERS, ENGAGING WITH A FREE GEAR. THE DIRECT DRIVE GEAR OR OVERSPEED DRIVEN GEAR MAY BE COUPLED WITH THE OUTPUT SHAFT THROUGH A SLIDING COLLAR AND A SYNCHRONIZER. THE INVENTION IS APPLIED IN PARTICULAR TO THE MODIFICATION OF FOUR-WHEEL DRIVE VEHICLES TO ADD THEM WITH OVERDRIVE SPEED.

Description

24599 1 7

  The present invention relates to a transmission device

  vehicle mission, with overdrive speed, particularly

  for four-wheel drive vehicles.

  Several types of fast transmission devices

  Overdrive have already been used. But all commercial types of these devices have severe limitations. Some common devices impose an overdrive gearbox that must be inserted in the drive shaft of a motor vehicle. it

  implies a longitudinal repositioning of the es-

  transmission or gearboxes, which

  in turn, a restructuring of the chassis supports necessary to support these essential elements

  gearbox and transmission. In a provision

  of the trade, an auxiliary gearbox for overdrive

  is provided at the output of the gearbox, but it is coupled only with a pair of wheels of a four-wheel drive vehicle. As a result,

  vehicle has no possibility of speed overtaking

  when driving with four wheels

  for propulsion by its four wheels.

  In another common device, the box block

  speeds is shifted backwards relative to the trans-

  vehicle mission so that an auxiliary box of

  overdrive speeds can be interposed between the trans-

  mission and the gearbox. This leads to

  structure and poor mounting support for these essential elements. The gearbox is shifted backwards in the longitudinal direction of approximately

  300mm, so new media is needed.

  In addition, the use of an auxiliary gearbox

  further aggravates the constraints of encumbrance for the

  motor train, normally very small footprint.

  The invention therefore relates to an adaptation device

  overdrive speeds for four-wheel drive vehicles

  cié with a current gearbox. No box

  xiliary is necessary. On the contrary, some elements which are normally provided as standard elements throughout the transmission are simply replaced by other elements according to the invention, but without the need to reposition the gearbox. On the contrary, replacement elements are easily used in an existing gearbox for a motor vehicle to have an overdrive. The overdrive gear used has

  fully synchronized gears, with a

  nual. The additional elements that are needed can

  may be mounted without modification of the transmission or chassis. The only modification exception required is the drilling of a hole in the floor for the lever

  overdrive. The unit of speed sur-

  multiplied according to the invention is essentially an article

fixed by bolts.

  A characteristic of the overdrive speed device

  folded according to the invention lies in the fact that, in the embodiment which comprises a main drive pinion,

  the latter is not coupled by grooves on the

  primary motor, but is mounted to rotate relative to this shaft. In this embodiment, a direct drive gear is coupled for direct transmission from the main shaft to the main drive gear. Alternatively, an overdrive sprocket is coupled in the same manner with the primary shaft and transmits the driving force through a free sprocket to an overdrive sprocket which rotates about the primary shaft. A

  sliding collar is permanently coupled by cane-

  lures with the primary motor shaft, but it can be de-

  placed in the longitudinal direction, in engagement with the direct drive gear when the overdrive speed is not desired, or in engagement with the overdrive gear. A synchronizer is arranged in the longitudinal direction between the speed driven gear

  overdrive and the drive pinion

  However, the transmission can be easily and synchronously transferred from the normal direct drive to the overdrive speed. Another embodiment of the invention does not include a main drive gear and the drive motor gear 245991t

  direct turns around the primary shaft. A pinion of

  overdrive also rotates on the primary drive shaft. The direct drive sprocket and the overdrive sprocket meshes with a free sprocket which has a large diameter section meshing with a

  single driven pinion and with the drive pinion gear

  recte, and also a smaller diameter section that meshes with the overdrive gear. Strength

  the driving gear is alternately supplied to the drive gear of

  direct or speed gear overdrive by a

  sliding collar on the primary motor shaft.

  The choice of the particular embodiment is deter-

  undermined by the particular configuration of the box of

  the vehicle. For example in a gearbox of a four-wheel drive vehicle manufactured by Toyota, the driving force is transmitted from the gearbox to a common secondary shaft for the front wheels and the rear wheels of the vehicle. In this gearbox, modified according to the invention, a main drive gear is used and it rotates on the primary drive shaft. An engine pinion

  overdrive and a drive pinion gear

  are coupled to rotate with the main motor shaft.

  The driving force is transmitted alternately from the pinion

  direct drive motor or over-speed gear motor

  multiplied by a sliding collar mounted so as to

around the motor shaft.

  In other types of vehicles, a gearbox has separate output shafts for the front wheels and the rear wheels of the vehicle. For example, a gearbox of the Dana model manufactured by Dana Corporation of Fort Wayne, Indiana, has a secondary shaft for the rear wheels of the vehicle, aligned in the longitudinal direction with the drive shaft and coupled with

  the differential of the rear wheels by universal joints.

  A separate output shaft is coupled with the front wheels of the vehicle and is offset laterally with respect to the transmission housing. In a gearbox of this

  like, the change of speed supernumerated according to the

  This is done in the same way using the same 245991t gearbox housing. But this embodiment

  does not have a main drive gear. The sprocket

  drive and the overdrive sprocket rotate around the primary drive shaft from the vehicle transmission. A sliding collar is driven by the primary motor shaft and is arranged around it. This sliding collar can be engaged with the direct drive motor pinion and can be moved in the longitudinal direction to be engaged with the overdrive gear. A loose gear is added to be coupled with the driven gear which is coupled only with the rear wheel output shaft and not with the shaft

  output of the front wheels. Overdrive sprocket

  folded and the pinion of direct engagement meshes with the pi-

  free but with different toothed sections to obtain different gear ratios, depending on whether the

  overdrive sprocket or the idler gear

  recte is engaged in order to transmit the driving force

from the primary motor shaft.

  In the modification of the Dana 20 gearbox, the primary drive shaft is uncoupled from the universal joint

  of the drive shaft of the rear wheels. A modern tree

  primary replacement is coupled by the pinion

  free and by the driven pinion with the output shaft on the-

  what is the driven gear. The output shaft is accom-

  with the motor shaft of the rear wheels by the universal joint

  sal. This embodiment of an overdrive speed device according to the invention places the rear wheels in

  direct drive or overdrive.

  : 30 Another benefit of this latter provision is that

  the transmission line is lowered. In a mode of

  the distance from which the transmission line is lowered is 92mm in the case of a Dana gearbox.

  20. Because of the change in the angle of the transmission line

  mission, this embodiment of an overdrive speed device according to the invention makes it possible to obtain a speed

  almost constant angularity between the motor shaft and the

  conducted. This reduces the stress on the universal joints

  versal. More particularly, the initial angle of the transmission line in four-wheel drive vehicles having the Dana gearbox 20 is 170, or 13 or

  This variation depends on the model of the vehicle. Because of

  sound of this strong transmission line angle, the universal joints wear out quickly. After mounting the overspeed device according to the invention, on these vehicles,

  the angle of 17 is reduced to 6,680, the angle of 13 is

  to 6,180 and the angle of 10 is reduced to 1,959. This re

  greatly increases the angular velocity of the tree

  which the driven gear is mounted with respect to the

transmission of the rear wheels.

  In previous devices, there is no room

  in the vehicle to have an over-speed device

  multiplied in the transmission line. The devices

  can not be placed on the drive shaft.

  On the contrary, they require that the transmission line be cut. The overdrive speed device according to the invention does not require modifying the chassis or modifying or shortening the transmission line. The inventory saves vehicle use by reducing fuel consumption and also allows the vehicle to travel with a reduction in the speed of rotation of the vehicle.

motor and noise reduction.

  With a manual transmission, the device according to the

  vention can go into overdrive, without delay

  and at any speed, With automatic transmissions

  the change is made at any speed after a brief delay while the transmission is in neutral. The different modes of realization of the invention are located entirely above the lowest line of the

  vehicle. They do not reduce the ground clearance of the vehicle.

  when traveling on rough terrain.

  Both embodiments can be mounted in the desired vehicle in a minimal amount of time and with minimal expense. The mounting of the embodiment with the main drive gear takes only four hours while the mounting of the embodiment in which the drive gear and overdrive gear rotates on the primary drive shaft takes only about one hour and half. Both embodiments are simple and the parts needed to modify a vehicle for overdrive speed can be produced at a price

relatively low.

  Other features and advantages of the invention

  will be better understood by reading the description that will

  follow several examples of implementation and referring to

  in the accompanying drawings in which:

  FIG. 1 is a perspective view of a mode of

  4 is a detailed view of an overdrive lever for the embodiment of FIG. 1, FIG.

  FIG. 3 is an elevational section through the armature

  primary motor of the gearbox of Figure 1,

  FIG. 4 is a simplified section showing the function

  tioning of the embodiment of FIG. 1 in overdrive speed,

  FIG. 5 is a simplified section showing the function

  of the embodiment of FIG.

rect,

  FIG. 6 is a section through the main drive shaft

  mayor of a gearbox modified according to another embodiment of the invention,

  FIG. 7 is a simplified section showing the function

  of the embodiment of FIG.

rect,

  FIG. 8 is a simplified section showing the function

  the embodiment of FIG. 6 in overdrive, and FIG. 9 is a curve illustrating the reduction of

  relative angular velocity obtained with the method of

of Figure 6.

  Overdrive speed device for a box

  wheeled vehicle speeds will therefore be described in

  FIGS. 4 and 5. A cylindrical main shaft 12 with grooves arranged in the longitudinal direction is

  coupled with a drive shaft, not shown,

  Figure 14 is a left-hand pinion, the teeth of which, indicated at 16, are directed radially with respect to the main shaft. , and is coupled to drive the axles of the vehicle which, at their

  turn, spin the wheels. The main gear 14 com-

  also carries an annular hub 18 with axial radial grooves 19 and directed outwards. Bearings not shown in the simplified views of Figures 4 and 5 are interposed between the main pinion 14 and the main shaft 12, so that the pinion 14 is coupled

  with the shaft 12 only by the device according to the invention.

  A 32-tooth direct-drive gear 20 has outer teeth 22 and inner splines 24 so that it rotates integrally with the main shaft.

  12. The direct drive pinion 20 is shifted in the direction

  longitudinal direction relative to the main pinion 14 and a gear wheel 26 of overdrive speed is further shifted along the main shaft 12. The gear 26 of overdrive speed is internally splined at 28 on the main shaft 12, and it comprises a larger diameter section carrying radially outwardly directed radial teeth. An overdrive gear 32 has a smooth inner surface which rotates unrepresented bearings around an annular sleeve 34 of the pinion 26. The driven pinion 32 is splined externally at 38 and

  it has radial teeth 40 directed outwards.

  A player 42 comprises a free gear 43 with a sec-

  toothed tooth 44 of small diameter whose teeth 46 in

  The free gear 43 also has a toothed section 48 of larger diameter whose teeth 50 mesh with the teeth 40 of the toothed wheel.

  driven pinion 32. The free pinion 43 is fluted on a wire

  free run 52 parallel to the main shaft 12. Due to the relative diameters of the toothed sections 44 and 48, the pinion 43 increases the speed relative to the drive pinion 26. The driven pinion 32 is therefore continuously driven to

  a speed higher than that of the motor pinion 26.

  A sliding annular collar 54 includes canes

  inner lugs 56 of small diameter and internal grooves

  57 larger diameters, shifted in the direction

  longitudinal The sliding collar 54 can be

  place in the longitudinal direction on the main tree

  pal 12, under the effect of a fork 58 which moves relative to the shaft 12. In the position of Figure 4, the grooves 57 of the collar 54 meshes with the corresponding splines 19 of the main pinion 14. Moreover, ,

  the flutes 56 of the collar 54 mesh with the canes

  corresponding lures 38 of the gear wheel 32 speed on-

  multiplied, and are disengaged from the splines 22 of the pinion gear 20, when the collar is shifted axially to the right, in the overdrive speed position shown in Figure 4. but, when the collar is

  shifted to the left in the direct-drive position

  5, these grooves 56 are disengaged

  splines 38 of the gear wheel 32 speed overdrive

  folded and meshes with the grooves 22 of the pinion 20 of

  direct catch. Regardless of the position of the necklace

  smoothing 54, the splines 19 and 57 of the axial hub 18 of the

  main gear 14 and collar 54 are continuously

  pledged. Likewise, the direct drive pinion 20 and the overdrive gear pinion 32 rotate continuously at different speeds around the main shaft 12. The speed of rotation of the main pinion 14 depends on that of the pinion gear 32 of overdrive speed. and pinion 20 of direct engagement with which the sliding collar

54 is engaged.

  Figure 1 shows a gearbox 60 provided as initial equipment of a four-wheel drive vehicle, for example a Toyota military vehicle, but modified according to the invention. The gearbox 60 contains

  the elements of Figures 4 and 5, as well as other

  as will be explained later. This gearbox 60 has transverse and opposite mounting tabs 62 and 64, with mounting holes 66, as shown in FIG. 1. The gearbox 60 is fixed to the chassis of the vehicle by bolts threaded into these holes. The gears of the gearbox 60 deliver a motive force by a differential transmission shaft b, not shown, which is coupled with the

  wheels of the vehicle and which rotates in the sleeve 68

lie longitudinal.

  A concave casing 70 of overdrive speed replaces the initial flat end plate whose gearbox 60 is initially equipped. The casing 70 is fixed by bolts 72 on the boot 60. A cylindrical housing 74, shown in FIG. 3, is defined

  by a cylindrical cap 76 projecting from the car-

ter 70.

  On the side of the gearbox 60, the plate of

  Plane retainer provided as initial equipment is removed.

  Gears and main shaft provided as equipment

  initial with the boot 60 speeds are also disassembled.

  A side cover 78 replaces the flat retaining plate

  provided as initial equipment. The lateral casing 78 com-

  carries an opening which receives an axis 80 serving as

  culation for a lever 82 for speeding overdrive

  folded shown in detail in Figure 2. The lever 82

  ends at its upper end by a spherical handle

  84 and at its lower end by a slot which

  receives a dowel coupling pin 170, representing

  shown in FIG. 3 and which is intended to displace the col-

  sliding link 54 in the longitudinal direction, of the

described manner.

  The main shaft 12 is a long cylindrical shaft

  dinal, fluted on its outer surface with 10 or 16 cane-

  lures 88, depending on the year of exit of the vehicle. The ar-

  head 12 comes out of a collar 90 of the transmissi-

  sion, not shown, of the vehicle and it enters the gearbox 60. The main shaft 12 comprises at its

  end a threaded axial stud 92, of reduced diameter.

  On this threaded stud 92 is screwed a nut 94 of extension

  shaft, with a smooth cylindrical outer shape,

  carrying a housing 96 of hexagonal shape intended to receive

see a tightening tool.

  The overdrive geared motor pinion 26 comprises radial teeth 30 and annular sleeves 98 and 100 formed in one piece and directed in opposite longitudinal directions with respect to the shaft 12. The outer surfaces of the annular sleeves 98 and 100 are smooth. The inner surface of the sleeve 98 is smooth while the sleeve 100 has internal grooves 102

  which meshes with the grooves 88 of the main shaft 12.

  The sleeve 98 rotates in a plain bearing 104 which centers it

  in the axial housing 74 of the cup 76 of the casing 70.

  The player 42 comprises the free axis 52 which rotates between the transverse end wall of the overdrive speed housing 70, and an opening in a transverse mounting plate 106 interposed between the housing 70 and the gearbox 60. O-rings 108 are disposed at each end of the free shaft 52 which is held in position by a locking tab 110 on the exposed surface

  of the casing 70. The locking tab 110 penetrates into a

  one side of the opposite end of the shaft 52 and

  it is held in position with a locking screw 112.

  Thrust bearings 114 and a trim 116

  hold the idle gear 43 in longitudinal position cor-

  right, with the teeth 46 of section 44 of smaller di-

  meter meshing with the teeth 30 of the motor gear 26 of vi-

  overdrive. The teeth 50 of the section 48 of larger diameter meshes with the teeth 40 of the driven pinion 32. A sliding bearing 118 disposed around the shaft 52 allows

  free gear 43 to turn on him.

  The main gear 14 is disposed between thrust bearings 130 and is mounted to rotate about an annular bearing 186. The latter rests on an annular support

  188 fluted on the main shaft 12 near the collar of trans-

  90. The main gear 14 is therefore kept immovable

  bile in the longitudinal direction relative to the tree

  main 12, but he can turn on him.

  The gear 32 of overdrive speed has a collar

  annular link 120 with outer splines 38 des-

  designed to mesh with the grooves 56 of the collar

24599 1 7

  Smoothing 54. The pinion 32 rotates around the sleeve 100 of the overdrive gear 26, on an annular bearing 122 interposed between them. A thrust bearing 124 in the form of a ring reduces the friction between the transverse surfaces facing the drive pinion 26 and the pinion

  led 32 speed overniultipliée.

  The end of the collar 32 of the overdrive gear 32, directed towards the main gear 14 comprises

  a frustoconical, frustoconical, frictionally directed surface 126

  outward. Likewise, the direct drive pinion 20 has an outwardly directed inclined friction engaging surface 128, also of frustoconical shape, but inclined towards the cap 76 of the overdrive gear housing 70. The direct drive pinion 20 comprises

  grooves 24 which meshes with the grooves 88 of the

  main motor 12, the pinion 20 direct drive is separated from the hub 18 of the main gear 14 by a thrust bearing 130. From the thrust bearing 130, the pinion

  direct drive extends to the hood 76 of the car-

  70, in an annular sleeve 132. The end of the collar 32 of the overdrive gear, pressed against the engagement surface 126, is coaxial with the sleeve 132 of the pinion 20 direct drive and can turn

relative to.

  A synchronizer assembly 134 is shown in FIG. 3, located radially outwardly of the collar

  132 of the pinion 20 of direct drive, in the longitudinal direction

  between the splines 22 of the pinion 20 of

  recte and splines 38 of the 32 speed driven gear wheel

  overdrive. The synchronizer assembly 134 comprises a module

  annular plate 140 with a flange 142 relatively

  in the longitudinal direction, a narrower connecting groove 144 and a radially inner base 146. In

  groove 144, the reduced section defines gutters

  in which there are snap rings

  148 of circular shape, exerting a radial force

  to 1 outside. Three longitudinal gutters are

  in the outer surface of the flange 142 of the hub 140, in which are arranged in the longitudinal direction of the claws 150 narrow. The jaws 150

* are linear linear pins with extrac-

  Matrices 152 directed radially inward. The craters

  bots 150 have bosses 154 on their outer surfaces.

  The jaws 150 are pushed radially outwardly by the rings 148 and engage with the inner surface of the sliding collar 54.

  tablets and can move in the long

  tudinal in the grooves of the flange 142 of the hub

  140 of the synchronizer. Ring rings of synchronization

  156 and 158 are mounted on the opposite faces in the

  longitudinal direction of the hub 140. The rings 156 com-

  carry a contact surface 160 frictionally engaged on the corresponding frustoconical contact surface 128 of the direct drive gear 20. In a similar way, the

  synchronizing ring 158 has a contact surface

  tact 162 engaged with friction on the contact surface

  126 gear 32 overdrive speed. Slots

  gitudinal 159 are formed in the edges of the bushings of

  synchronization 156 and 158 to the ends 152 of the craters

  150, in the direction of the synchronization hub 140.

  The outer surfaces of hub 140 and coupling rings

  156 and 158 are grooved to mesh with the splines 56 of the sliding collar 54. The movement

  longitudinal jaw 150 in the grooves of the glue

  142, in one direction or the other, locks

  natively the synchronizing ring 156 or 158 select

  with the synchronization hub 140, with the exception of

  sion of the other synchronizing ring. The jaws 150

  thus form an interlock mechanism and are accom-

  pleated by the friction of the bosses 154 with the collar

  smoothing 54 so as to move with him in the direction

longitudinal

  Sliding collar 54 has a section of more

  large diameter whose grooves 57 directed towards the

  the inner can engage the corresponding splines 19

  the longitudinal hub 18 of the main pinion 14. The grooves 57 of the collar 54 and the corresponding splines 19 of the pinion

  main 14 are still engaged, whatever

  the position of the transmission rod 170. The collar

  Sliding link 54 has an outer annular groove 164 coupled to the exhaust manifold 158 which limits

  longitudinal movement. The range 158 has branches

  slideably extending from each side of the sliding collar 54 and penetrating into the groove 164. At its radially outer end, the fork 158 terminates in a sleeve

  168 in the longitudinal direction pierced by a circular hole

  Jongitudinal area.-At its outer surface, in relation to

  the main shaft 12, the sleeve 168 comprises a plurality of housings

interlocking elements 171.

  The side walls of the housing 78 are pierced with a

  longitudinal wise parallel to the main motor shaft 12, and intended to receive a cylindrical rod 170 carrying a hatch 172 at its outer end. The rod 170 passes through the bore of the walls of the side casing 70 and an O-ring 174 seals the liquids. The face of the outward facing outboard casing 78 has a radial bore which is threaded to receive a set screw 178. The set screw 178 compresses a spring

  helical 180 so as to modify the biasing force

  inward direction, exerted on the rod 170 by a latching ball 182. Clamping or loosening

  the adjusting screw 178 changes the return force of

  that the overdrive speed interlocking lever 82

  folded can be handled as well as the ball of

  The latch 182 rests in one of the dwellings 171 and

  hold the fork 166 motionless in the longitudinal direction

  until the handle 82. is again maneuvering

Vree.

  Figures 1 and 2 show that the engagement lever 82

  Overdrive speed can be entered by hand

  by the handle 84 and be moved around the locking pin

  80. The rod 170 moves in the longitudinal direction, in the longitudinal bore of the lateral casing 78, as shown in FIG. 3, under the effect of the force transmitted by the chained coupling 172. This rotation of the lever 82 and the longitudinal movement of the rod acts on the fork 58 to sdectively adjust the longitudinal position of the sliding collar 54 relative to the main shaft 12. The fork 58 is placed in a longitudinal position determined by the engagement of the

ball 82 in dwellings 171.

  During the operation of the embodiment of the

  Figures 1 to 5, a rotation in the opposite direction of the

  guilles of a watch of the lever 82, from the position of FIG. 2, brings the device according to the invention to

  the state of transmission of motive power at overdrive speed

  tipliée. Turning in the opposite direction of needles

  of a watch of the lever 82 pushes the rod 170 towards the rear.

  in the position shown in Figure 3. This movement

  longitudinally is transmitted to the sliding collar 54 by the fork 58. The fluted inner surface of the collar

  54 acts on the bosses 154 of the claws 150 and the drives

  do not backwards into the grooves of the synchronization hub

  140, in such a way as to force the right-hand ends 152 of the claws 150 to bear against the synchronizing ring 158. This forces the synchronizing ring 158 towards the rear and increases the frictional contact between its surface 162 and the corresponding surface 126 of the gear wheel 32 speed overdrive. As a result, the synchronizing ring 158 begins to rotate with the driven pinion 32, which rotates continuously due to the coupling between the main shaft 12, the overdrive gear 26, the free gear 43 and the driven gear. 32. When the synchronizing ring 158 begins to rotate, the ends 152 of the jaw 150 quickly come into alignment with the

  longitudinal slots 159 of the synchronizing ring 158.

  This mechanism locks the synchronizing hub 140 and the synchronizing ring 158 so that they rotate together and allow the splines 56 of the sliding collar 54 to engage the splines of the timing ring 158 and then the splines 38 of the driven gear. 32. When this occurs, the highest speed produced from the rotation of the main shaft 12 is transmitted by the player 42 to the driven pinion 32 by the sliding collar.

  54, to the main drive gear 14.

  Conversely, when the handle 82 is turned clockwise from the position of FIG. 2, the rod 170 is pulled to the left from the position of FIG.

  entrafne sliding collar 54 to the left and this last

  deny brings with it jaw 150 by friction

  bosses 154 with the inner surface of the collar.

  When the handle 82 is sufficiently rotated, the engagement ball 182 is aligned with the center of the engagement housings 171. In this position, the jaws 150 engage neither the synchronizing ring 156 nor the synchronizing ring 158. , so that neither the grooves 38

  32 of the overdrive gear, or the cane-

  lures 22 of the direct drive pinion 20 are engaged with

  sliding collar 54. In this neutral position,

  a driving force is transmitted to the collar 54.

  Continuing the rotation of the lever 82 clockwise from the position of FIG. 2, brings the slide collar 54 further to the left so that the left ends 152 of the jaws 150, as shown in FIG. 3 come to rest with the synchronizing ring 156. When the ends 152 of the claws rest against the synchronizing ring 156, the

  friction between the surface 128 of the pinion gear 20

  and the friction surface 160 of the synchromesh ring.

  Chronizing 156 is increased. When this friction increases, the synchronizing ring 156 begins to rotate with the

  pinion 20 direct drive and the orabots 150 can fina-

  to align with the slots 159 of the

  timing ring 156. This allows the collar to

  smoothing.54 to move further to the left, as seen in FIG. 3, to the direct engagement position with the flutes 156 of the collar engaged with the flutes

  22 of the pinion gear 20, as shown schematically

  Figure 5. In this position, the landing gear

  described above transmits the driving force of the tree

  12, by the direct drive pinion 20 and the collar

  sliding link 54 engaged with it, towards the reel sprocket

principal 14.

  It should be noted that the modification according to the invention

  of a gearbox, which is otherwise conventional, of a vehicle

  four-wheel drive, is done without changing the posi-

  longitudinal direction of the main shaft 12 nor the position

  length of the gearbox 60. The only modifications

  Fications that are required for the gearbox 60 relate to the inner gears and other mechanisms described, replacing parts provided by the factory. The gear boot 60 is further modified by the addition of a casing 70 of overdrive speed and a crankcase

  side 78, with the lever 82 for speeding over-

  multiplied. A hole must be cut in the floor of the vehicle to receive the lever 82. This lever is thus disposed about 175 mm behind the shifter lever, not shown, and offset from it by about 125 mm in a current device of change

speed to the floor.

  Another embodiment of the invention for modifying a Dana 20 speed boot will now be described with reference to FIGS. 6 to 8. A Dana 20 gearbox is used in an International Harvestor Scout.

  Ameri-can Motors Jeeps, both of which are

  four-wheeled vehicles. This embodiment is shown in simplified form in FIGS. 7 and 8. A tree

  main motor 200 is coupled with a transmission line

  mission of a vehicle so that the driving force is supplied by the right side to the main shaft 200, as

  FIGS. 7 and 8 show it.

  recte rotates on the main shaft 200 and is coupled to drive the vehicle wheels by an output shaft 204 and a driven gear 206 which drives the wheels

  back. An overdrive pinion gear 208 also turns

  The overdrive gear 208 has an annular hub 210 with axial splines directed to a splined hub 212 on the drive pinion 202. A free sprocket 214

  turns on a free shaft 216 parallel to the axis of the

  200. The free gear 214 has an annular sleeve 218 whose opposite ends bear

245 9917

  toothed parts of different diameters. A small diameter toothed portion 220 meshes with the overdrive gear 208 while a larger diameter toothed portion 222 meshes with the direct drive gear 202. A sliding collar 224 is driven by the main shaft 200 so as to rotate with it. As shown in FIG. 7, the collar 220 is splined on a synchronizer 226 and can engage the drive pinion 202. In a variant,

  the collar 224 can move in the longitudinal direction

  relative to the main shaft 200 to engage the overdrive pinion 208 via the

  synchronizer 226, as shown in FIG.

  The embodiment of the overdrive speed device

  shown in simplified form in FIGS. 7 and 8 is shown in greater detail in FIG.

  gearbox cover 228 has a movable portion

  Concave, rigid steel bar 230 fixed to a steel mounting plate 232 by machine bolts 234 which are threaded into longitudinal holes along the perimeter of the molded portion 230. A trim 236 is

  interposed between the molded part 230 and the plate of

  232. The latter has a thickness of about 15.6mm beyond its perimeter, but it includes a collar 238 in the longitudinal direction that enters the box

  240 provided as initial equipment of the vehicle.

  cule. The mounting plate 232 is fixed on the gearbox 240 by countersunk screws 242 which penetrate

  in the mounting plate 232, along its perimeter.

  A tapered bearing 244 is positioned on the main shaft

  200 and receives rolls 246 around his circle.

  conference. The rollers 246 are held in a raceway 248, so that the main shaft 200 rotates in the collar 238 of the mounting plate 232. An engagement ring 250 immobilizes the conical bearing 240 in the longitudinal direction, against a opposite shoulder on the main shaft 200. The latter has grooves of larger diameter at its end, penetrating into the gearbox. This end is directed

  to the right, seen in Figure 6.

  The direct drive gear 202 has 33 teeth and rotates on the main shaft 200 through a bronze bearing 252 located in the housing 230, just inside the mounting plate 232. As shown in FIG.

  In the figures, the direct drive pinion 202 comprises a

  yeu 212 whose end forms a surfrce 213 of engagement

  Frictional friction, directed towards the synchronizer 226.

  The synchronizer 226 is very similar in its design.

  the synchronizer 134, and operates in much the same way. The synchronizer 226 has an annular hub 254 splined on the main shaft 200. The hub 254 has a narrow coupling groove, of reduced cross-section, defining annular grooves in which there are circular engagement rings 256, exerting a radial outward force Three longitudinal grooves are formed in the outer surface of the hub 256 and the narrow jaws 258, in

  the longitudinal direction, form a locking mechanism

  and are frictionally coupled to their outer bosses with the sliding collar 224 so as to move with it in the longitudinal direction. Annular synchronizing rings 260 and 262 are arranged

  to rub on the corresponding engagement surfaces

  overdrive pinion gears 208 and 212 of the

  direct drive gnon 202. The synchronizing rings 260 and 262 are arranged annularly around the main shaft 200 on each side of the synchronization hub 254.

  The claws 258 are moved in the longitudinal direction

  nale so as to alternately engage slots in the edges of the synchronizing rings 260 and 262 facing the ends of the jaw. Outdoor Surfaces

  synchronization hub 254 and timing rings

  260 and 262 are splined to engage inner splines of the sliding collar 224. The synchronizer 226 is immobilized in the longitudinal direction by a snap ring 264 which penetrates into a radial groove of

the main shaft 200.

  Overdrive gear 208 has 37

  teeth and turns on the main shaft 200 through the

  median of a bronze bearing 266. The hub 210 of the pinion

  208 of overdrive speed has an engagement surface

  frictional arrangement 215, frustoconical. At its opposite end, the pinion 208 bears against a conical bearing 270

  supporting rollers 272 turning in a roadway

  274. An annular lining 276 is positioned at the end of the molded portion 230 and a flat lid

  278 is bolted to an opening by bolts of

  China 280 in order to close the molded part 230 at the end

of the main shaft 200.

  The idle gear 214 rotates on the free shaft 216, by

  two bearings 282 at opposite ends of this shaft. The ar-

  free end 216 has a reduced diameter portion at its right end 284 and the sealing is provided on the mounting plate 232 by an O-ring 286 A thrust washer 288 is disposed on the shaft 216,

  near the end 284, in order to withstand the

  In a similar manner, a thrust washer 288 is disposed at the opposite end of the idle gear 214 to resist the thrust of the smaller diameter toothed portion 220. The toothed portion 222 of large diameter has 37 teeth with a pitch diameter of, 1mm. The toothed portion 220 of larger diameter has 33 teeth with a pitch diameter of 75.9mm. The tightness at the end 290 of the free shaft 216 is ensured in the

  molded part 230 by an O-ring 292, and this end

  mity is kept immobilized by a locking tab.

  294 penetrating into a radial groove of the end 290 of the shaft 216, and-fixed on the molded portion 230 by a bolt 296. The idle gear 214, comprising the sleeve 218 and the toothed portions 220 and 222 of small and large diameter, turn on bearings 282 while the tree

  free 216 is locked in position in the cover 228.

  The output shaft 204 is supported at a closed end in the mounting plate 232 by the gaskets 236 and 288, and rotates in a roller bearing 300 located in a cup-shaped housing of the mounting plate 232. The driven gear 206 is splined on the output shaft 204 and is held in position in the direction

  longitudinally by the roller bearing 300 and by a shoulder

  It is located on the output shaft 204. A speedometer motor gear 302 is disposed near the driven gear 206 and is supported by a roller bearing 308 disposed on

  the output shaft 204. The roller bearing 308 is now

  held against a set 310 constituted by three concentric sleeve elements. Shims 311 load the sleeve assembly 310 and an outlet cover 312 holds the shims 311 in position, and is secured to the molded portion 230 by machine bolts 314. The seal caliper 316

  universal is attached to the output shaft 204 by rods

  lures, so that this stirrup rotates the tree of

transmission of the rear wheels.

  The transmission line from the output shaft

  204 is lowered by 92mm from the transmission line

  mission of the gearbox 240 initially supplied with the vehicle. This change brings an advantage

  regarding the wear of the universal joint. More particularly

  In particular, the yoke 316 of the universal joint is much better aligned with the rear wheel drive shaft in the embodiment of FIG.

  the angular velocity between the output shaft 204 and the

  transmission of the rear wheels.

  Figure 9 shows the advantage of this modification. The relative angular velocity W of the initial output shaft

  of the gearbox 240 relative to the transmission shaft

  Rear wheel mission is indicated by the sinusoid 318 on a spin cycle. As shown in the figure, a maximum angular velocity ratio of 1.046 revolutions per minute occurs during a half-turn while the angular velocity ratio of the shaft 204 at the angular velocity

  of the rear wheel driveshaft is 0.956

  the other half turn. With the overdrive gearbox

  folded according to the invention, the angular velocity is represented

  by a much smaller amplitude curve, representing

2459917 7

  The maximum angular velocity ratio in the first half-turn is 1.07 while it is 0.993 in the other half-turn. This much more uniform angular velocity considerably reduces the wear of the universal joints of the transmission line, which

goes along their longevity.

  The reason for the reduction of the angular velocity

  tive is that the angle of the transmission line with respect to the output of the gearbox (which according to him invention

  the output shaft 204) is considerably reduced.

  Duit. In the Jeep CJ-5 model manufactured by American Motors, the initial angle of the transmission line is 17. After

  the assembly of the embodiment represented by the FIGS.

  res 6 to 8, the angle becomes 6,680 Similarly, in the model

  Jeep CJ-7 four-speed, the angle of the trans-

  mission is reduced from 13 to 6.18 o In the CJ-7 model to

  three speeds, the angle of the drive shaft is

from 10 to 1,950.

  There is absolutely no need to cut the transmission line

  mission on the Jeep or Scout models. The distance between the gear boot 240 and the attachment of the yoke 316 to the shaft 204 is 128.6mm. This distance is only slightly greater than the initial distance between the output of the gear boot 240 of the Dana type 20 and the universal joint which is 108mm. The difference is only 4.8mm, it's

  to say the increase required by the extra sprockets

  added and enclosed in the molded part 230. The

  transmission line tolerance absorbs unaltered

  this increase in thickness. Therefore, there is no need to cut or modify the drive shaft

rear wheels of the vehicle.

  The speed change fork 322, the cylindrical coupling rod 324, the overdrive lever 326 and its handle 328 function in the same manner as the corresponding structure described in FIG.

  view of the embodiment of Figures 1 to 5.

  In the embodiment of FIG. 6, and with reference to FIGS. 7 and 8, the vehicle can roll in direct contact with the sliding collar 224 in the position of FIG. 7. The main motor shaft 200 rotates driving with him I hub synchronizer 254 which is grooved on him. The collar 224 is engaged by the synchronizer 226 with the pinion 202 of direct engagement, by splines of the hub 212. When the sliding collar 224 is moved by the lever 326 to the psition of Figure 7, the driving force is transmitted from the main motor shaft 200, by the synchronizer 226, to the sliding collar 224 and from there,

  direct drive pinion 202. The pinion 202 of

  correspondingly with its larger diameter portion 222 of the free assembly 214 the driven gear 206 and the spindle

  outlet 204 coupled by splines, at an annular speed

  relatively small gular. This is so because the engrè-

  direct drive pinion 202 with the

  222 of the free sprocket 214 involves the transmission of driving force from a pinion of relatively small diameter (pinion 202 direct drive) to a free pinion

  of relatively large diameter (section 222). This results in

  that the idle gear 214 rotates at a relatively low angular velocity. This relatively low speed is

  transmitted to the driven gear 206 and the output shaft 204.

  The pinion 208 of overdrive speed meshes permanently with

  With the section 220 of the idle gear 214. Thus, the gear 208 of overdrive rotates even if the collar

  slide 224 is in the position of FIG.

  But in this position, the speed gear 208 sur-

  multiplied is not coupled as a transmission device

  power, but it turns freely on the

  tie 266 around the main shaft 200.

  When it is necessary to pass the vehicle's rear wheels in overdrive, the lever 326 is manipulated to move the sliding collar 224 in the longitudinal direction, from the drive with the drive pinion 202 to the meshing with the pinion

  208 overdrive speed. This is done through

  synchronizer 226 which operates in the same way.

  The hub 210 of the overdrive pinion 208 is engaged by the splines 224 of the collar 224. In this way, the driving force is

  transmitted from the main motor shaft 200, by the synchronism

  226 and the sliding collar 224, the hub 210 of pinion 208 speed supernumerary. The latter is a

  relatively large pinion that rotates the den-

  relatively small head of the idle gear 214. This half

  rotates a relatively small pinion

  Relatively large gnon increases the angular velocity of the toothed section 222 of more tassel diameter, which in turn increases the angular velocity of the driven gear 206 and the output shaft 204. As a result, the passage between the gear position sunriultipliée of Figure 8 and the direct grip position of Figure 7 is in a manner very similar to that described with regard

  of the embodiment of Figures 1 to 5.

  In the position of FIG. 8, the direct drive gear 202 further meshes with the larger diameter section 222 of the idle gear 214. This causes the drive gear 202 to rotate at a higher speed than if it were engaged with the drive gear. main motor shaft 200 by the sliding collar 224. But with the sliding collar 224 in the position of FIG. 8, the pinion 202 of

  direct connection is not coupled with the transmission line.

  mission when the vehicle is overdrive, but it turns freely on the 252 bearing as shown

Figure 6.

  It is understood that many modifications can be made by those skilled in the art to the modes of

  described and illustrated by way of examples

  restrictive without departing from the scope of the invention.

Claims (12)

  1 - Overdrive gear train for a wheeled vehicle gearbox, characterized   in that it comprises a main motor shaft (12)   with a transmission line of the vehicle, a main driving gear (14) which rotates on said driving shaft   and coupled to drive the wheels of the vehicle.   and comprising a hub (18) axially elongated with a pinion gear (20) attached to said main drive shaft for rotation with it, and movable in the   longitudinal direction relative to said axial hub of   said main drive gear, a drive gear (26) of   overdrive speed fixed on said main drive shaft   pal to rotate with it, a pinion gear (32) overdrive speed which rotates on said main motor shaft and which can be moved in the longitudinal direction relative to said axially elongated hub of said pinion   main motor and with respect to said main gear   recte, a free gear (42) for producing a higher mechanical speed meshing with said motor pinion   overdrive and with said gear pinned with   overdrive, and a sliding collar (54) disposed   around said main drive shaft engaged with said   yeu of said main drive gear and movable   in the longitudinal direction so as to engage alter-   natively said gearwheel gear overdrive and said direct drive gear.   2 - Gear train according to claim 1, characterized   characterized in that it further comprises a synchronizer (134) for alternately coupling said sliding collar with said direct drive gear and said driven gear of overdrive speed.   3 - Gear train according to claim 2, characterized   characterized in that said synchronizer (134) comprises a   Yeu annular synchronizer (144) rotatably mounted   coaxially on said main drive shaft, and   annular gears (156,158) mounted at   opposite ends of said synchronizer hub, one of the 24 59 9 1 7   said sync rings having a surface of   contact intended to rub on said pinion gear   the other of said timing rings   both a contact surface for rubbing on said overdrive gear, and a   latch (154) cooperating between said synchronous hub   said synchronizing rings so as to lock alternatively one of the rings of   synchronization on said synchronization hub, to the ex- clusion of the other.   4 - Gear train. according to claim 3,   characterized in that longitudinal grooves are formed   on the outer surface of said synchronizer hub,   corresponding notches being formed in the edges of the   said synchronizing rings turned towards said synchronizer hub, said locking device comprising   several claws (154) that can move in the direction   longitudinally in said grooves for locking in said slots one or the other of said timing rings, said jaws being driven by said sliding collar (54) so as to move   with him in the longitudinal direction.   Gear train according to claim 3, characterized in that said direct drive gear (20) is   maintained coupled by splines with said self-propelled shaft   main drive (12) said sliding collar (54) being held coupled by splines to said hub (18) of said main drive gear (14), and being splined to engage said synchronizer hub (144), said drive gear and said overdrive speed driven gear   being fluted to receive said sliding collar.   6 - Adaptation gear train for one speed   overdrive, intended for a transmission gearbox   mission of a four-wheel drive vehicle, comprising   a splined main motor shaft driven by the transmission   the vehicle and coupled to transmit the   driving force on the four wheels of the vehicle,   characterized in that it comprises a bearing (129) grooved internally and with a smooth outer surface,   positioned on said main motor shaft (12), a   a main gear (14) which rotates on said bearing (129) and which has a toothed section (16) coupled to drive said four wheels, and an axially elongated and axially grooved hub (18), a splined direct drive gear (20). internally, on said main drive shaft so as to rotate with it and offset in the longitudinal direction with respect to said pinion   main engine axially elongated, and carrying cane-   the external lures, a driving gear (26) of speed   multiplied having a sleeve (100) with a smooth outer surface splined on said main drive shaft for rotation therewith, and another annular sleeve (98) at its end opposite to and supported on said main drive shaft, an outer bearing ( 104) disposed around said sleeve (98) of said overdrive motor gear, opposite said main drive shaft, a bearing (122) splined on said main drive shaft   disposed around said sleeve (100) of the drive gear of   overdrive, a driven gear (32) with overdrive speed   folded, externally splined and rotatable on said bearing (122) about said main drive shaft, and offset in the longitudinal direction relative to said take-up gear   directly (20), a free gear (42) producing an increase   speed, meshing with said overdrive gear and with said speed gear wheel   overdrive, and a sliding collar (54), integrally grooved   secondly, arranged on said main drive shaft, ac-   splined with said hub (18) of said   main motor, and able to move in the direc-   longitudinally so as to engage the splines alternately said overdrive gearwheel gear and said direct drive gear.   7 - Gear train according to claim 6, characterized   in that it further comprises a synchronizer (134) for alternately coupling said sliding collar (54) with said direct drive gear (20) and said overdrive gear (32) and comprising a ring hub Timing (144) rotatably mounted about said main motor shaft, externally splined and engaged with said sliding collar, and annular timing rings (156, 158) to the   opposite ends of said synchronization hub, and   frictionally engaging said synchronization hub,   ternatively with the direct drive pinion and with the   overdrive speed driven gear.   8 - Gear train according to claim 7, characterized   in that it further comprises a coupling device   longitudinally reciprocating, radially disposed (58) coupled to said slide collar (54), a side cover plate (78) with a concave housing for receiving said coupling device, and attached to said boot speeds, and   comprising an opening, a lever 82 for passing through   overdrive articulated by a fulcrum   on the cover plate, and a support rod   plement (170) coupling said radial end of said coupling device with said passage lever into   overdrive, at an offset from said point of articulation.   9 - Erging train according to claim 6, characterized   characterized in that it further comprises a housing (70) attached to said gearbox, with an axial concave housing (74) which receives and supports said outer bearing (104) about said sleeve (98) of said speed motor gear overdrive, opposite to said main drive shaft, a   device (52) being provided for supporting said sprocket gear   ber. - Gear train for overdrive speed   intended for a wheeled vehicle gearbox,   characterized in that it comprises a main drive shaft (200> coupled with a vehicle transmission line, a drive gear (202) which rotates on said main drive shaft, and coupled to drive the wheels of the vehicle, a gear (208) of overdrive speed which rotates on said main drive shaft, a pinion 24599 1 7   driven (206) coupled to drive the rear wheels of said vehicle, a free gear (214) producing an increase   mechanical speed, meshing with said speed gear-   overdrive, said direct drive gear and said driven gear, and a sliding collar (224) driven by   said main motor shaft, arranged around it, capable of   It must be engaged with a direct drive pinion and   before moving in the longitudinal direction so   alternatively engaging said overdrive gear folded.   11 - Gear train according to claim 10, characterized   characterized in that said pinion (208) of overdrive speed and said pinion gear (202) comprise axially elongate hubs, said slide collar (224) being axially movable in the longitudinal direction the   along said main drive shaft so as to engage   ternatively the hub of said direct drive gear and the   hub of said overdrive gear.   12 - Gear train according to claim 11, characterized   characterized in that it further comprises a synchronizer (226)   for coupling said sliding collar (224) alternately   with said pinion gear and said pinion speed and overdrive.   13 - Erging train according to claim 12, characterized   characterized in that said synchronizer (226) includes an annular synchronizer hub (254) which is coaxially rotatable on said main drive shaft, and annular rings   synchronization (260,262) mounted at the opposite ends   said synchronizing hub, one of said synchromesh rings   chronization comprising a contact surface for   frictionally engaging a corresponding surface of said   direct coupling, the other of said synchronizing rings   having a contact surface for frictionally engaging a corresponding surface of said overdrive gear, a locking device (258)   being provided between said synchronizer hub and said   synchronization so as to lock alternately   one of the specified synchronization rings with 24 5 99 1 7   said synchronizing hub, excluding the other.   14 - Gear train according to claim 10, characterized   characterized in that said idle gear (214) is mounted on a   shaft (216) parallel to said main drive shaft, and   carries a small diameter toothed portion (220) which meshes with said overdrive gear (202), and a larger diameter toothed portion (222) which meshes with said driven gear (206), said large diameter portions and small diameter of said free pinion being coupled to turn together.   Gear train according to claim 14, characterized   characterized in that said large diameter and small diameter portions of said idle gear (214) are connected by a sleeve (218), bearings (282) being interposed between said sleeve and said free shaft.