FIELD OF THE INVENTION
The invention relates to an Electronic accelerator pedal module (EAPM).
BACKGROUND AND PRIOR ART OF INVENTION
Control pedals are typically provided in a motor vehicle, such as an automobile.
which are foot operated by the driver. Separate control pedals are provided for
operating brakes and an engine throttle.
When the motor vehicle has a manual transmission, a third control pedal is
provided for operating a transmission clutch. The control pedals are typically
connected to control devices by cables or other mechanical transmission devices
which convert the limited rotary motion of the pedals into useful mechanical motion
at the control devices to control operation of the motor vehicle. The engine throttle is
typically connected to an accelerator pedal through a mechanical cable such as a
Bowden cable. This lnechanical linkage has a desirable and functional "feel" wherein
the pressure required for advancing the control pedal to accelerate the motor vehicle is
greater than the pressure required for maintaining the pedal in a fixed position to
maintain the motor vehicle at a constant speed. This difference of required pressures
is often referred to as a "hysteresis effect". The pressure required to advance the
control pedal is typically relatively high. This is desirable to obtain adequate return
pressure to return the pedal to the idle position in a desired amount of time when foot
pressure is removed from the control pedal. The pressure required to advance the
control pedal is easily provided when accelerating but would become uncomfortable
over time to maintain a relatively constant speed. Therefore. the hysteresis effect is
important in providing a reasonable force for maintaining the accelerator pedal in
position to comfortably drive at a generally constant speed while providing an
adequate return force for returning the control pedal to idle to decelerate the motor
vehicle.
Further, it has been observed that when conventional pedals operated in a
housing of said assembly, an inner side surface of friction pad touches to pedal &
outer side of friction pad surface touches to inner surface of housing. Thus, friction
takes place between friction pad outer surface & housing inner surface (so called as
rubbing surface as shown in figure 1) and thereby with a period of time there is wear
and tear started on the inner surface of the housing.
In conventional pedal construction the spring force acts on friction pad and
hence, friction wearing of surfaces takes, due to which, the gap between friction pad
and housing increases. This change in gap results in non-uniform frictional force and
so unequal pedal force during acceleration & de-acceleration.
The drawbacks associated with conventional technology
a. Wearing of parts may change operating force & frictional torque;
b. Horizontal deployment is also not possible in conventional technology; and
c. Operating & releasing force can be varying by replacing lever with different
leverage ratio.
Therefore, the inventors of the present invention provided solution to
overcome the above-said demerits in the electronic pedal accelerator of vehicles.
OBJECTS OF THE INVENTION
The primary objective of the present invention is to provide an electronic accelerator
pedal module whereby a uniform friction force between pedal and fiiction pad during
operation of pedal.
Yet another objective of the present invention is to provide an electronic accelerator
pedal module whereby there is no wear and tear take place of housing of pedal
assembly during operation of pedal.
Yet another objective of the present invention, wherein an electronic accelerator pedal
module is smoothly operable in varying operating force.
SUMMARY OF THE INVENTION
The present invention relates to an electronic accelerator pedal module (EAPM)
comprising a pivoted pedal, one end of pedal defining a friction surface. The pedal is
provided with a friction pad which is positioned and held by a first arm of a lever and
a second arm thereof holding a spring mechanism with respect to a spring holding
hole formed on the pedal. The rotation movement of the pedal is transferred to a
sensor via an appropriate mechanism.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The invention itself, together with further features and attended advantages, will
become apparent from consideration of the following description, taken in
conjunction with the accompanying drawings. One or more embodiments of the
present invention are now described, by way of example only, with reference to the
accompanied drawings wherein like reference numerals represent like elements and in
which:
Figure 1 represents the sectional diagram of a conventional electronic accelerator
pedal module;
Figure 2 represents front view of an electronic accelerator pedal module in accordance
with the teachings of the present invention;
Figure 3 represents side view of the electronic accelerator pedal module in accordance
with the teachings of the present invention;
Figure 4 represents other side view of the electronic accelerator pedal module in
accordance with the teachings of the present invention after removing the cover;
Figure 5 represents an exploded view of the electronic accelerator pedal module in
accordance with the teachings of the present invention;
Figure 6 represents a side sectional view of the electronic accelerator pedal module in
accordance with the teachings of the present invention;
Figure 7 represents a top sectional view of the electronic accelerator pedal module in
accordance with the teachings of the present invention;
Figure 8 represents the side sectional view of the electronic accelerator pedal module
in accordance with the teachings of the present invention showing the force vectors
acting on the pedal module in a working state;
Skilled artisans will appreciate that elements in the drawings are illustrated for
simplicity and have not necessarily been drawn to scale. For example, the dimensions
of some of the elements in the drawings may be exaggerated relative to other elements
to help to improve understanding of embodiments of the present invention.
DETAIL DESCRIPTION OF THE INVENTION
While the invention is susceptible to various modifications and alternative forms,
specific embodiment thereof has been shown by way of example in the drawings and
will be described in detail below. It should be understood, however that it is not
intended to limit the invention to the particular forms disclosed, but on the contrary,
the invention is to cover all modifications, equivalents, and alternative falling within
the spirit and the scope of the invention.
Before describing in detail embodiments it may be observed that the novelty and
inventive step that are in accordance with the present invention reside in the
construction of the electronic accelerator pedal module, accordingly, the drawings are
showing only those specific details that are pertinent to understanding the
embodiments of the present invention so as not to obscure the disclosure with details
that will be readily apparent to those of ordinary skill in the art having benefit of the
description herein.
The terms "comprises", "comprising", or any other variations thereof, are intended to
cover a non-exclusive inclusion, such that a setup, device that comprises a list of
components does not include only those components but may include other
components not expressly listed or inherent to such setup or device. In other words,
one or more elements in a system or apparatus proceeded by "comprises.. . a" does
not, without more constraints, preclude the existence of other elements or additional
elements in the system or apparatus.
Accordingly, the present invention relates to an Electronic accelerator pedal assembly
comprising: a pedal (6) capable of moving fro~na rest position to a depressed position
as a result of force applied thereto; return springs (16, 17) urging said pedal toward
said rest position: and a frictional force generating mechanism for generating a
frictional force according to movement of said pedal (6), said frictional force
generating mechanism comprising a sliding guide path defining a sliding surface (19)
on the pedal, and characterized such that the pedal being operationally configured
with a pivotally (13) mounted lever (1 1) having two arms in the housing (10) of said
assembly, wherein the horizontal arm (1 la) of lever contain a friction member (12)
being pressed on the outer surface (19) of the pedal (6) so as friction action take place
between pedal outer surface and friction member, and the vertical arm (1 lb) of the
lever being connected with a return springs (16, 17) which is coupled to inner side
(20) of the pedal to achieve a uniform friction force between friction member and
pedal. the said springs (16, 17) force to rotate the lever in clockwise direction, and
movement of pedal is being sensed by sensor assembly (9) through a pinion
mechanism (14), which is located in between bracket 4 and cover 10.
Another aspect of the present invention relates to an electronic accelerator pedal
module as claimed in claim I, wherein the friction member /pad is a piece of plastic
block, having upper surface held in horizontal arm of lever (1 1) and lower surface is
in contact with outer surface (1 9) of pedal lever.
Yet another aspect of the present invention, wherein the return springs are two
concentrically placed springs (16) and (1 7), sandwiched between vertical arm I I b of
lever and spring holding hole on pedal (6). The lever 11 is allowed to rotate through
pivot 13. With the spring force, the lever 11 always has tendency to rotate in
clockwise direction.
Yet another aspect of the present invention, wherein the lever (1 1) having leverage /
length ratio of horizontal arm to vertical arm is 1:l to 0.5:5 for obtaining variable
operating force, which is not possible in conventional technology.
Referring to figures 2, 3 and 4, the EAPM of the present invention is mounted on a
vehicle fire wall (not shown) with the help of 3 mounting holes shown by 1, 2, and 3.
A sensor shown by 9 is mounted on pedal assembly about cover side. The pedal 6 is
assembled between cover & bracket 4. Pedal full throttle rotation is arrested by a
stopper 7 mounted on the pedal and a stopper 8 mounted on the bracket 4. Full throttle
opening requires 15" degree pedal rotation about a pivot 5. However, depending upon
operational needs, this angle can be either increased or decreased.
Referring to figures 5, 6 and 7, the pedal 6 is pivoted through pivot 5 which is a part
of bracket 4. The pedal rotates in counter clock wise direction in shown view to
achieve full throttle position. The rotation movement of the pedal is transferred to the
sensor 9 via an appropriate mechanism.
One end of pedal comprises of friction surface or so called rubbing surface 19. The
friction takes place between friction pad 12 & pedal 6 on friction area 19. The friction
pad 12 is positioned and held by a lever 11. The lever has two arms, a first arm of the
lever holds the friction pad 12 and the second arm holds a spring mechanism, which
by way of example may comprise of a small spring 16 and a large spring 17.
The spring mechanism is sandwiched between an arm of the lever 19 and a spring
holding hole 20 formed on the pedal 6. The lever 11 is allowed to rotate through pivot
13. With the spring force, the lever 1 1 always has tendency to rotate in clockwise
direction. The rotation movement of the pedal is transferred to the sensor 9 for
example via a pinion 14 which can be located in between bracket 4 & cover 10. To
operate the pinion, the pinion 14 is provided with teeth 15 and the same interfaces
with appropriately formed (or provided) teeth 18 of the pedal 6.
The pinion 14 has teeth 15 that mater with teeth 18 of the pedal 6 and rotates in
opposite direction of pedal movement. One end of pinion is located in bracket &
another end 21 is coupled to the sensor 9.
The sensor form example can comprise of a rotor 25 which in turn can accommodate
a magnet which exhibits movement with respect to one or more hall sensors. Other
alternative constructions of the sensor which is contact based is also possible. The
cover 10 can be clamped to the bracket 4 by way of example, with the help of snap
arrangement 24. A bush bearing 22 and a bearing bush 23 may be provided between
the bracket 4 and the cover 10 and the same may be slide fitted. The pedal can be
configured to rotate around both bearing bushes.
Referring to figures 1 and 8, which represent construction of a conventional EAPM
and construction of the EAPM in accordance with the teachings of the present
invention, it can be observed that the construction of the conventional EAPM is such
that the pedal rotates along with friction pad. An inner side surface of friction pad
touches to pedal & outer side of friction pad surface touches to inner surface of
housing. Thus, friction takes place between friction pad outer surface & housing inner
surface (so called as rubbing surface as shown in figure 1). Spring is fitted in between
housing & pedal. So the spring force vectors act in direction of pedal as well as in
direction of housing.
On the other hand, the construction of the EAPM in accordance with the teachings of
the present invention is such that the rubbing takes place between pedal outer surface
& inner surface of friction pad as can be seen from figure 8. The spring assembly is
fitted in between Pedal & Lever and not on housing as is the case in the prior art. The
friction pad is fitted on the lever side and the lever is allowed to rotate in direction as
described above after complete pedal assembly is actuated.
In conventional pedal construction the spring force vector acts on friction pad and
hence, friction wearing of surfaces takes, due to which, the gap between friction pad
and housing increases. This change in gap results in non-uniform frictional force and
so unequal pedal force during acceleration & de-acceleration.
By adopting the construction as described in the present application, the friction takes
place between friction pad & pedal. During pedal operation wearing happens but the
force of friction & vector direction remains constant because spring force allows lever
to rotate towards pedal surface. So there will be uniform frictional force. This results
in keeping constant pedal force during entire pedal operations.
In the table 1 provided herein below a comparison between the main features of the
present invention and the prior art are summarized in a non-limiting manner.
Table 1 : Comparison between the present invention and the prior art
Sr no
1
2
3
4
6
Parameter
Friction between
Spring force
Between
Rubbing surface
Wearing
compensation
Pedal operating
feel
Pedal stuck
Conventional
Construction
Friction Pad & Housing
Pedal & housing
Friction Pad & housing
Not found
May change
Due to moisture absorption
more interference in
between friction pad &
housing.
Minda Construction
Friction pad & Pedal
Pedal & lever
Friction Pad & pedal
Spring force on lever
allows to rotates &
compensate for gap.
Constant
Due to moisture
absorption plastic swells
but due to leverage effect
no interference. Only
Surface contact possible
WE CLAIM
1. An Electronic accelerator pedal assembly comprising:
A pedal (6) capable of moving from a rest position to a depressed position as a
result of force applied thereto;
return springs (1 6. 17) urging said pedal toward said rest position; and
a frictional force generating nlechanism for generating a frictional force
according to movement of said pedal (6), said frictional force generating
mechanism comprising a sliding guide path defining a sliding surface ( 1 9) on
the pedal, and characterized such that the pedal being operationally configured
with a pivotally (1 3) mounted lever (1 1) having two arms in the housing (1 0)
of said assembly, wherein the horizontal arm (1 la) of lever contain a friction
member (12) being pressed on the outer surface (19) of the pedal (6) so as
friction action take place between pedal outer surface and friction member,
and the vertical arm (I 1 b) of the lever being connected with a return springs
(16, 17) which is coupled to inner side (20) of the pedal to achieve a uniform
friction force between friction member and pedal. the said springs (16, 17)
force to rotate the lever (1 1) in clockwise direction, and movement of pedal is
being sensed by sensor assembly (9) through a pinion mechanism (14). which
is located in between bracket 4 and cover 10.
2. The electronic accelerator pedal module as claimed in claim 1, wherein the
friction member /pad is a piece of plastic block, having upper surface held in
horizontal arm of lever (I 1) and lower surface is in contact with outer surface
(1 9) of pedal lever.
3. The electronic accelerator pedal module as claimed in claim 1, wherein the
return springs are two concentrically placed springs (16) and (1 7). sandwiched
between vertical arm 11 b of lever and spring holding hole on pedal (6).
4. The electronic accelerator pedal module as claimed in claim 1, wherein the
lever (1 1) having leverage / length ratio of horizontal arm to vertical arm is 1: 1
to 0.55 for obtaining variable operating force.