FIELD OF INVENTION
This invention relates to a shifting system for fifth and reverse gear of vehicle.
The system prevents double engagement in synchronized gear, thereby
resulting in smoother gear engagement.
BACKGROUNDIPRIOR ART OF THE INVENTION
Shifting system for gears particularly for fifth and revere gear is majorly of two
types, which is known to have been provided in the art.
One type comprises a synchronizer to prevent blockage and grinding noise
while meshing of gears and another type makes use of simple sliding for
engagement of gears.
Now, reference may be made to fig. 1, wherein in the conventional shifting
system shaft (1) for shifting between reverse and fiAh gear is connected to fifth
gear fork (2) by means of a pin (3) at one end. A yoke (4) is provided to actuate
said shaft.'
Further, a bracket (5) is mounted on the wall of transmission box to support
lever (6), which is engaged with a reverse gear arm (7). Said gear arm (7) is
pinned to the shaft
With the movement of yoke, fifth gear .fork and reverse gear move leading to
engagement and disengagement of fifth and reverse gear respectively.
Again, reference may be made to fig. 2 indicating the same conventional
shifting system in Neutral Position (I), fifth gear engaged (11) and reverse gear
engaged (111) condition.
The lever is used for sliding movement of reverse gear itself, which applies force
on one side of the gear. This results in tilting of the gear, thereby causing
improper engagement of the same. Further drawbacks associated with the
above discussed provision can be listed hereinbelow:-
- High blockage occurrence due to sliding mesh reverse gear
- Occasional Improper & noisy shifting
- Larger transmission box.
- Uncomfortable feeling.
Now, reference may be made to the following prior arts:-
A known art discloses a power transmission box which comprises a box body,
an input shaft, an output shaft, a driving gear, a driven gear, a shifting clutch,
a stirring mechanism and a hydraulic motor, wherein the box body comprises a
left box body and a right box body. A' bearing seat and an inner spline are
arranged inside a gear hole of the driving gear, two ball bearings are arranged
inside the bearing seat, and the input shaft is provided with an outer spline.
The shifting clutch is composed of a shifting meshing sleeve, a meshing sleeve
locating mechanism and a driving gear inner spline, wherein the meshing
sleeve locating mechanism is arranged on the 'input shaft.
It comprises a power transmission box without use ~f balls for. interlocking.
- High manufacturing cost.
- Does not fulfill requirements of the proposed invention.
CN202867814U:- The utility model relates to a double self-locking gearshift
device which comprises a transmission shaft, a sliding gear sleeve, a shifting
fork and a gearshift shaft, wherein a V-shaped groox3e is formed in the sliding
gear sleeve. A first spring and a first steel ball are arranged inside the
transmission shaft. A self-locking mechanism is composed of the first steel ball,
additionally arran'ged on a gearshift tail cover, wherein a second spring and'a
I second steel ball are installed inside the locking ball guide sleeve. A second
self-locking mechanism is composed of the locking ball guide sleeve, the sccond
spring, the second steel ball and. a gearshift shaft.
Thus, it comprises double self-locking gear shift device together with a shifting
fork and a gear shift shaft.
Disadvantages: -
, - More number of components. This may lead to increase in weight and
cost.
Another prior art discloses mechanisms of a gear switch manipulation and
starting control for tractors, and relates to the field of the gear switch
manipulations which are installed on covers on tractor gearboxes and starting
mechanisms. The mechanisms of the gear switch manipulation and the
starting control for the tractors comprising a control lever connected with a
main shaft through a control lever connecting plate and a main shaft
connecting plate. The main shaft penetrates through an upper cover of a gear
box. A right oil seal, a right shaft sleeve, a limiting sleeve, a limiting spring, a
left shaft sleeve and a left oil seal are arranged on the main shaft in a sleeved
mode. A deflector rod is installed on the main shaft and a reversing guide plate
is installed in the upper cover of the gear box. Right fork shaft, and left fork
shaft are provided with respective fork. .
Another prior art discloses a. gear-shifting interlocking mechanism of an .
automobile transmission, which includes a box body, as well as a first gearshifting
shaft, a second gear-shifting shaft and a third gear-shifting shaft
distributed in parallel sequentially. An interlocking pin is arranged in an
interlocking pin hole of the second gear-shifting shaft. A disconnection surface
disconnected in the shaft hole radial direction is arranged at one end of the box
body, in which interlocking steel balls are arranged on the disconnection
surface and between shaft holes and matched with the interlocking pin; and an
interlocking cover plate is arranged on' the disconnection surface and covers
the interlocking steel balls.
It is used only for stopping the dual gear engagement not for gear shifting. It
consists of three shaft linear arrangement using two ball and interlock pin in
the fixed b.ox and cover plate assembly.
Disadvantage: -
It uses balls for only interlocking not for toggling from one gear to another.
Still another prior art relates to dual engagement prevention device of a manual
transmission to prevent the dual engagement of shift shafts by inserting an
inter lock ball into the holes of the shift shafts and to improve the assembling
performance and the manipulation of the shift shafts using one inter lock ball
and to maximally use a space by keeping the shift shafts in a regular angle
without aligning the shift shafts.
It is used only for stopping the dual gear engagement and not for gear shifting.
It consists of three shaft arranged in triangle by using single ball in fixed box
and cover plate assembly.
Disadvantages:-
It also uses balls for only interlocking not for toggling from one gear to another.
Again, it is not applicable to transmission of present invention.
CN203082197U:- The utility model relates to a novel gear shifting mechanism
of a transmission. The mechanism comprises a gear shifting arm, a fork shaft,
a guide shaft, a five-gear fork and a gear-reversing control fork. The five-gear
fork is provided with a C-type clamping rirrg, the fork shaft and the guide shaft
are provided with corresponding clamping ring installation grooves and are
located on the gear-reversing control fork.
It consists of single yoke ball operated fifth and reverse mechanism using
additional fixed guide shaft, wherein reverse gear is not actuated directly.
Further, there is provision of fixed guide shaft with no means for interlocking
both fifth and reverse gear simultaneously, wherein hanging cantilever type
fifth gear is provided. Here, motion of reverse arm is controlled by pin in arm
groove.
It uses additional guide shaft i.e. four shaft mechanism. Further, it is suitable
for spur type reverse gear. However, the. same is incompatible for synchronized
helical type reverse gear.
Still another prior art provides transfer device in a four-wheel drive vehicle. The
transfer device includes a high-speed/low-speed shifting shaft and a twowheellfour-
wheel shifting shaft disposed side by side in proximity to each
other. A krst elliptic groove and a first semicircular groove are formed in an
outer peripheral surface of the high-speed/low-speed shifting shaft in an
axially spaced relation to each other and a second seinicircular groove
corresponding to. the first elliptic groove and a second elliptic groove
corresponding to the first semicircular groove are formed in an outer peripheral
surface of the two-wheellfour-wheel shiftirlg shaft in an axially spaced relation
to each other.
In this invention balls are used only for motion control &, not for interlocking.
Fork is mounted on single shaft & in rigid link instead of two shafts & indirect
link using ball. It involves single yoke operating two shafts using two balls.
-7-
Disadvantages: -
The balls don't help in interlocking. Further, it is comparatively more
complicated and involves more hard control tight tolerances (if required).
Hence, the present invention has been developed so as to address the aforesaid
shortcomings.
OBJECTS OF THE INVENTION'
The primary object of the present invention is to provide a simple & compact
shifting system for fifth and reverse gear of vehicle.
Another object of the present invention is to provide a shifting system for fifth
and reverse gear of vehicle which is reliable and efficient.
Further object of the present invention is to provide a shifting system for fifth
and reverse gear of vehicle which is cost effective.
Still another object of the present invention is to provide a shifting system for
fifth and reverse gear of vehicle-which also avoids blockage in reverse gear by
providing synchronized type gear, thereby resulting in smoother & quieter
reverse gear engagement.
SUMMARY OF THE INVENTION
According to this invention, there is provided a shifting system for fifth and
I reverse gear of vehicle comprising of atleast two shafts with one of them
I supporting a fork.at each end for fifth and reverse gear engagement, wherein-a
yoke is provided with each of the shafts for shifting into fifth or reverse gear
and third or fourth gear.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
I Further objects and advantages of this invention will be more apparent from
I the ensuing description when read in conjunction with the accompanying
I drawings and wherein:
Fig. 1 shows: conventional shifting system through a fork for synchronized fifth
gear and reverse spur gear by sliding motion.
Fig. 2 shows: engagement of fifth and reverse gear of the shifting system
according to prior art.
Fig. 3 and 4 shows: shifting system for fifth and reverse gear in accordance
with the present invention.
Fig. 5 shows: shafts (upper and lower) for fifth and reverse gear, and high
speed gears respectively.
1. Fig. 6 shows: angular stopper of the present invention.
I, Fig. 7 shows: different positions (neutral, engaged and disengaged) during ,
reverse gear shifting.
Fig. 8 shows: different positions (neutral, engaged and disengaged) during fifth
gear shifting.
DETAIL DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE
ACCOMPANYING DRAWINGS:-
The present invention is directed to shifting syste~rfio r synchronized fifth and
reverse gear of vehicle. The invention is particularly a novel shifting system for
synchronized fifth and reverse gear for a compact manual transmission. Said
system comprising of ball operated shifting fork system for fifth and reverse
gear. This constitutes a mechanism to cater the requirement of shifting
synchronized fifth' and reverse gear in a compact manual transmission system
by means of ball and circlip operated shifting forks.
Now, reference may be made to fig. 3 and 4, in which the novel shifting system
of the invention comprising of two shafts, out of which one shaft (1) is provided
for 3rd and 4th gear with use of one shifting fork and another one shaft (2) for
fifth and reverse gear with use of two shifting fork. A fork (3) is provided for
fifth gear at one end and a fork (4) is provided for reverse gear at another end.
Said forks are supported by both shafts as shown in the figure 3 and 4. Fork
(5) is integrally provided with the shaft (1) for 3rd and 4th gear (high speed
gears). Again, there is provision of a yoke (6) and another yoke (7) on the shaft
(2, 1) for fifth and reverse gear and for 3rd and 4" gear respectively. Again, e
balls (8 and 9) & circlips (10 & 11) is are provided between shafts, fork and
yoke on both sides as shown. The forks are is provided for shifting respective
gear(s) during engagement and disengagement.
Said yoke (6) is used for transmitting motion to shaft for shifting of respective
gears i.e. providing motion to shaft of fifth and reverse gear for fifth and reverse
gear shiftihg and similarly, yoke (7) is used for providing motion to shaft of high
speed gears for 3'd and 4th gear shifting. Further, a circlip (10) is provided
I around the shaft (2) for transferring motion from shaft (2) to fork (3) for shifting
fifth gear. Likewise, another circlip (1 1) i- used for transferring motion from
! said shaft to fork (4) for shifting of reverse gear.
The shaft as shown in the figure 5 is having atleast two grooves (G) on the
same side so as to accommodate the ball therein. The ball transfers motion
from the shaft to fork and is also used to interlock.
The shaft (1) transfers motion from the yoke (7) to the fork (5) so as to shift
1 .
I high speed gears. In a similar way, the shaft (2) transfers motion from the yoke
(6) to the fork (3 and 4) of fifth and reverse gear one at a time in order to shift
1 . ' fifth and reverse gear respectively.
The system also comprises an angular stopper (12) to hold the shaft (2) of fifth
and reverse gear through its hole (H) and also to hold the shaft (1) for high
speed gears through its peripheral extension (S) as indicated in fig. 6. This
provision is a simplistic solution for restricting rotation of shaft for fifth and
reverse gear i.e. to arrest rotation degree of freedom of the shaft.
The transmission box accommodating the shifting system for gears is smaller
in size than that in prior art. This is because the space required for operation
of the shifting system is more in case of prior art, whereas shifting system of
the present invention requires' less space during its operation. Thus, the .
I transmission box is compact.
I .
I Now reference may be made to Fig.7.
I Reverse Fork Engagement (Yoke movement direction Right)
- Yoke (fifth & Rev) move right moves shaft (fifth & rev) along with it.
- Shaft (fifth & Rev) applies force on circlip (1 1) & moves it to the right.
- Circlip (1 1) moves Fork of Rev gear right making Reverse gear engaged.
. - Spherical ball inside Fork for Rev gear moves right along with fork.
Fork Fifth gear Interlock during Reverse gear engagement
- Whe,n shaft (fifth & Rev) moves to right no component applies load on
Fork (fifth) to make it move to right.
- Inertia is provided by fifth gear sleeve onto fifth fork which further
hinders its movement.
- In neutral ijosition, grooves on shaft (fifth 8s Rev) and shaft (High speed)
are infront of each other. Hence, spherical ball can move freely into
grooves.
- When shaft (5th & Rev) is. not in neutral position Grooves are no longer ,
infront of each other. Spherical ball always remains inside fork & as fork
(fifth gear) is not moving due to inertia, ball is pushed out of groove on
shaft (5th & Rev) due to its movement and is now in Fork (fifth gear) &
Groove on shaft (High speed).
- Shaft (High speed) is fixed during (fifth & Rev) gear shifting. Spherical
ball is also fixed because it is inside Fixed shaft groove.
- Ball locks the Fork (fifth gear) providing the interlock functionally during
Reverse gear shifting.
I .
Fork, Rev gear dis-engagement (Yoke movement left):
I - Spherical ball inside Fork (Rev gear) & shaft (fifth & Rev) is in mechanical
I
lock with shaft (fifth & Rev) because it resides inside shaft groove.
- When shaft (fifth & Rev) moves from engaged position to neutral position
(left direction), ball also moves along with shaft towards left (ball & shaft
I
I are locked together.
- Ball applies force on Fork (Rev gear) which makes Fork (Rev gear) to
move towards neutral making gear dis-engaged.
-12-
- Fork (fifth gear) cannot move during dis-engagement due to its locking
with fxed shaft (high speed).
Now, reference may be made to Fig.8.
5th Fork Engagement (Yoke movement direction left1
I - Yoke (5th & Rev) moves left which moves shaft (5th & Rev) along with it.
1 ' - Shaft (5th & Rev) applies force on circlip (10) & moves it to the left.
- Circlip (10) moves Fork (fifth gear) left making (fifth gear) engaged.
- Spherical ball inside fork (fifth gear) moves left along with fork (fifth
gear).
Fork Rev gear interlock during 5th gear engagement
- When shaft (5th & Rev) moves to left, load is applied on Fork (Rev) to
make it move to left.
- Inertial is provided by Rev gear sleeve onto Fork. Rev gear which further
restricts its movement.
- In neutral position grooves on shaft (fifth & Rev) and shaft (High speed)
are positioned infront of each other, wherein spherical ball can move
freely into grooves.
- When shaft (fifth & rev) is not in neutral position Grooves are no longer
infront of each other. In that case, spherical ball remains fixed inside
fork. Further, as fork (Re$ gear) does not move (explained above), ball is
pushed out of groove on shaft (fifth & Rev) due to its movement and is in
Fork (Rev gear) & groove on shaft (High speed).
- Shaft (High speed) is fixed during (fifth & Rev gear) shifting. Spherical
ball is also fured because it is inside fixed shaft groove.
- Ball locks the Fork (Rev gear) thereby activating the interlock functionally
during fifth gear shifting.
Fork fifth gear dis-engagement [Yoke movement right):
- Spherical ball inside Fork (fifth gear) & shaft (fifth & rev) is mechanically
locked with shaft (5th & Rev) because it resides inside shaft groove.
- When shaft (fifth & Rev) moves from engaged position to neutral position
(right direction), ball also moves along with shaft towards right (ball &
shaft are locked together).
- Ball applies force on fork (fifth gear) which makes fork (fifth gear) to move
towards neutral making gears to dis-engage.
- Fork (Rev gear) cannot move during dis-engagement due to its locking
with fixed shaft (high speed).
Advantageous Features:-
- Avoids reverse blockage & possibility of double engagement.
- Compact transmission box, wherein 3 forks operated by 2 shafts
effectively.
- Comfortable & silent feeling during operation.
- Accurate shifting.
- Efficient & Durable
It. is to be noted that the present invention is susceptible to modifications,
adaptations and changes by those skilled in the art. Such variant embodiments
employing the concepts and feaiures of this invention are intended to be within
the scope of the present invention, which is further set forth under the
following claims: -

WE CLAIM:
1. A shifting system for fifth and reverse gear of vehicle comprising of
atleast two shafts with one of them supporting a fork at each end for fifth
and reverse gear engagement, wherein a yoke is provided with each of the
shafts for shifting into fifth or reverse gear and third or fourth gear.
2. A shifting system as claimed in claim 1, wherein the shaft is provided
with atleast two grooves on the same side so as to accommodate a ball
therein.
3. A shifting system as claimed in claim 1 or 2, wherein a ball is provided
between the two shafts and forks on both sides.
4. A shifting system as claimed in any of the preceding claims, wherein two
shafts comprising of a shaft for fifth and reverse gear provided using two
forks and a shaft for third and fourth gear integrally provided with a fork.
5. A shifting system as claimed in any of the preceding claims, wherein an
angular stopper is provided holding the shafts for arresting rotation
degree of freedom of shaft for fifth sand reverse gear.
6. A shifting system as claimed in any of the preceding claims, wherein a
circlip is provided with the shaft of fifth and reverse gear for transferring
motion from the shaft to respective fork for shifting fifth gear.
7. A shifting system as claimed in any of the preceding claims, wherein
another circlip is provided with the shaft of fifth and reverse gear for
transferring motion from said shaft to respective fork for shifting of
reverse gear.
8. A shifting system as claimed in any of the preceding claims, is associated
with the advantageous features such as herein described.
9. A shifting system for fifth and reverse gear of vehicle substantially as
herein described with reference to'the accompanying drawings.