FIELD OF THE INVENTION
The present invention generally relates to a position sensor and more
particularly, to a gear shift lever position sensor that precisely detects plurality of
gear shift lever positions.
5
BACKGROUND OF THE INVENTION
Automobiles, in particular passenger cars, have varied type of
transmission systems such as Manual Transmission, Automatic Transmission,
and Automated Manual Transmission.
10
In general, an automatic transmission has plurality of gear shift lever
positions such as "Neutral", "Reverse" and "Drive". Further, in addition to the three
gear shift lever positions an Automated Manual Transmission also has "Manual +"
and "Manual - " positions. The automated manual transmission enables the driver
15 to run the vehicle either in automatic transmission mode or in manual
transmission mode.
Typically, in automatic transmission and automated manual transmission
systems sensors (position sensors) are employed to detect position of gear shift
20 lever and on the basis of the detected position of the gear shift lever, the desired
gear IS ascertained and the transm~ss~oISn e ngaged in the sa~dg ear by means of
aUXllldry tllULUl3 In Illc rrar~srrr~ssiuI r r I IL pusittar, -EirlP*r L-- =-- - C - c b c . t -
position sensor or a relative one (displacement sensor). Also, position sensors
2
can be linear, angular or multi-axis.
Conventionally, the position sensor sends the data to a transmission
control unit (TCU). The TCU uses the data provided by the sensor as well as the
5 data provided by the engine control unit (ECU) to determine in which gear position
the transmission is to be engaged. There are different types of position sensors
available such as, light sourced based sensors which are associated with each
shifting position of the gearshift lever and detect different positions of the gear shift
lever by way of interrupted beam path and magnet based position sensors which
10 detect the change in gear shift lever by determining the change in the magnetic
flux at the plurality of hall sensors (magnetic flux detection elements).
US8897974 B2 discloses one of the magnet based position sensors. The
disclosed gear selector assembly comprises of an internal mode switch having
15 detent lever, a plurality of magnetic field sensors, a control module, a first power
supply and a second power supply. In the assembly, each of the field sensors
sends an output current having a variable value, wherein the value of the output
current is indicative of at least one of the following: the direction of the magnetic
field from the corresponding magnetic track, a short circuit, and an open circuit.
2 0
Another type of magnet based positon sensor is disclosed in US4935698
A. This document talks about a sensor comprising hall elements and magnet
3
assembly for use as a proximity detector. Further, the sensor comprises of an
integrated circuit having two side-by-side hall elements, an amplifier,
interconnecting wiring providing the difference voltage between the two hall output
voltages at the input of the amplifier, and a Schmitt trigger circuit.
Yet another type of position sensor is disclosed in CN102537303 A. The
disclosed automated manual transmission control mechanism of an automobile
comprises a gear shifting control rod, a magnet, an upper base, a lower base, a
circuit board and a plurality of Hall sensors. Wherein the automated manual
10 transmission control mechanism of the automobile transmits gear information to
the automatic gearbox electrical control unit in a multi-channel combined signal
manner.
The aforesaid documents and similar disclosures which talk about varied
15 type of position sensors comprise of number of shortcomings and drawbacks
such as malfunctioning of electrical contacts and/or magnetic components,
undesirable output provided by the sensors due to close proximity with each other,
large number of sensors and bulky size of the position sensor circuit etc.
Accordingly, there remains a need in the prior art to have an improved
position sensor for gear shift lever which overcomes the aforesaid problems and
shortcomings.
However, there remains a need in the art for a gear shift lever position
sensor that precisely detects plurality of gear shift lever positions. In other words,
the gear shift lever position sensor which is reliable and provides the results with
5 minimal error. Further, the position sensor must have smaller size and minimum
number of components which require very nominal time to detect the gear shift
lever position.
OBJECT OF THE INVENTION
10 It is an object of the present invention to provide a gear shift lever position
sensor. Further, another object of the present invention is to provide a gear shift
lever position sensor which comprises of minimum number of components and
has longer life as compared to conventional gear shift lever position sensors. Also,
it is an object of the present invention to provide a gear shift lever position sensor
15 which has sufficient space in between detection elements in order to provide
precise output and facilitate redundancy request in case of any magnetic and/or
electrical failure.
SUMMARY OF THE INVENTION
20 Embodiments of the present invention aim to provide a gear shift lever
position sensor which enables detection of gear shift lever position precisely. The
disclosed gear sh~flte ver position sensor continuously detects the gear shift lever
position Also, in case of any magnetic andlor electrical failure the proposed gear
shift lever position sensor provides a specific output instead of any arbitrary value.
The gear shift lever position sensor is provided with the features of claim 1,
however the invention may additionally reside in any combination of features of
5 claim 1.
In accordance with an embodiment of the present invention, the gear shift
lever position sensor comprising a magnet, a first magnetic flux detection element,
a second magnetic flux detection element and a logic circuit. The magnet
generates magnetic flux in accordance with plurality of gear shift lever positions.
Further, the first magnetic flux detection element and the second magnetic flux
detection element generate output levels based on the magnetic flux generated
by the magnet. Also, the logic circuit is provided between the first magnetic flux
detection element and the second magnetic flux detection element.
In accordance with an embodiment of the present invention, the plurality
of gear shift lever pos~tions comprises, but not limited to, a reverse position, a
neutral position, a drive position and a manual mode position.
In accordance with an embodiment of the present invention, the first
magnetic flux detection element and second magnetic flux detection element are,
but not limited to, hall sensor.
In accordance with an embodiment of the present invention, the logic
circuit is, but not limited to, a NAND logic circuit.
5 In accordance with an embodiment of the present invention, the first
magnetic flux detection element is configured to detect the reverse position of the
gear shift lever.
In accordance w~tha n embodiment of the present invention, the second
10 magnetic flux detection element is configured to detect the drive position of the
gear shift lever.
In accordance with an embodiment of the present invention, the second
magnetic flux detection element is configured to detect the manual mode position
15 of the gear shift lever.
In accordance with an embodiment of the present invention, the logic
circu~its configured to detect the neutral position of the gear shift lever.
2 0 While the present invention is described herein by way of example using
embodiments and illustrative drawings, those skilled in the art will recognize that
the invention is not limited to the embodiments of drawing or drawings described,
7
and are not intended to represent the scale of the various components. Further,
some components that may form a part of the invention may not be illustrated in
certain figures, for ease of illustration, and such omissions do not limit the
embodiments outlined in any way. It should be understood that the drawings and
5 detailed description thereto are not intended to limit the invention to the particular
form disclosed, but on the contrary, the invention is to cover all modification/s,
equivalentls and alternativels falling within the scope of the present invention as
defined by the appended claim. The headings used herein are for organizational
purposes only and are not meant to be used to limit the scope of the description or
10 the claim. As used throughout this description, the word "may" is used in a
permissive sense (i.e meaning having the potential to), rather than the mandatory
sense (i.e. meaning must). Further, the words "a" or "an" means "at least one"
unless otherwise mentioned. Furthermore, the terminology and phraseology used
herein is solely used for descriptive purposes and should not be construed as
15 limiting in scope. Language such as "including", "comprising", "having",
"containing", or "involving" and variations thereof, is intended to be broad and
encompass the subject matter listed thereafter, equivalents, and additional subject
matter not recited, and is not intended to exclude other additives, components,
integzrs or steps. Likewise, the term "comprising" is considered synonymous with
20 the terms "including" or "containing" for applicable legal purposes. Any discussion
of documents, acts, materials, devices, articles and the likes are included in the
specification solely for the purpose of providing a context for the present invention.
8
It is not suggested or represented that any or all of these matters form part of the
prior art base or were common general knowledge in the field relevant to the
present invention.
5 In this disclosure, whenever an element or a group of elements is
preceded with the transitional phrase "comprising", it is understood that we also
contemplate the same composition, element or group of elements with transitional
phrases "consisting of', "consisting", "selected from the group of consisting of',
"including", or "is" preceding the recitation of the composition, element or group of
10 elements and vice versa.
BRIEF DESCRIPTION OF THE DRAWINGS
So that the manner in which the above recited features of the present
invention can be understood in detail, a more particular to the description of the
15 invention, briefly summarized above, may be had by reference to embodiments,
some of which are illustrated in the appended drawings. It is to be noted, however,
that the appended drawings illustrate only typical embodiments of this invention
and are therefore not to be considered limiting of its scope, the invention may
admit to other equally effective embodiments.
These and other features, benefits and advantages of the present
invention will become apparent by reference to the following text figure, with like
reference numbers referring to like structures across the views, wherein:
Fig. 1 illustrates an exploded view of a gear shift assembly having a gear
shift lever position sensor in accordance with one of the preferred embodiments of
5 the present invention.
Fig. 2 illustrates a block diagram of the gear shift lever position sensor of
fig 1 in accordance with another preferred embodiment of the present invention.
Fig. 3 illustrates a process flow of a method for continuous position
sensing of gear shift lever position in accordance with yet another preferred
10 embodiment of the present invention.
Fig. 4 is an exemplary illustration of a complementary bit pattern chart.
Fig. 5 is an exemplary illustration of a PCB layout of the gear shift lever
position sensor of fig. 2
15 DETAILED DESCRIPTION OF THE DRAWINGS
The present invention is described hereinafter by various embodiments
with reference to the accompanying drawing, wherein reference numerals used in
the accompanying drawing correspond to the like elements throughout the
description. This invention may, however, be embodied in many different forms
20 and should not be construed as limited to the embodiment set forth herein. Rather,
the embodiment is prov~deds o that this disclosure will be thorough and complete
and will fully convey the scope of the invention to those skilled in the art. In the
following detailed description, numeric values and ranges are provided for various
aspects of the implementations described. These values and ranges are to be
treated as examples only, and are not intended to limit the scope of the claims. In
addition, a number of materials are identified as suitable for various facets of the
5 implementations. These materials are to be treated as exemplary, and are not
intended to limit the scope of the invention.
Figure 1 illustrates an exploded view of the gear shift assembly (100)
having a gear shift lever position sensor (200) in accordance with one of the
10 preferred embodiments of the present invention. As shown in figure 1, the gear
shift assembly (100) comprises a gear shift lever assembly (102), a shifter box
(106) and a gear shift lever position sensor (200). The other known components of
the gear shift assembly (100) are obvious to a person skilled in the art and have
not been discussed here for the sake of brevity.
15
The shifter box (106) is configured to mount on to the vehicle. The shifter
box (106) comprises attachment holes to enable engagement of lower portion of
the shifter box (106) on to the vehicle. In other words, the lower portion of the
shifter box (106) may have flanges for mate-ably engaging with the vehicle body.
20 Also, the shifter box (106) is provided with retainer clips to facilitate retention of
cable sleeves.
In accordance with an embodiment of the present invention, the shifter
box (106) is made of, but not limited to, a polymeric material. Further, the shifter
box (106) is having a shape of, but not limited to, an inverted cup-shaped body.
5 The gear shift lever assembly (1 02) comprises a shift knob, a shift lever, a
shift pin and an axel lever selector. Further, the shift lever is having a pivot ball at
the bottom end. Preferably, the pivot ball is molded onto the shift lever. The
functioning and characterist~cso f the components of the gear shift lever assembly
(102) are apparent to a person skilled in the art and have not been shown and
10 elaborated here for sake of conciseness.
The gear shift lever position sensor (200) comprises a magnet (202). As
shown in figure 1, the magnet (202) is placed underneath the gear shift lever
assembly (102). Further details of the gear shift lever position sensor (200) have
15 been described below in reference to figure 2.
Figure 2 illustrates a block diagram of the gear shift lever position sensor
(200) of figure. 1 in accordance with another preferred embodiment of the present
invention. As shown in figure 2, the gear shift lever position sensor (200)
20 comprises the magnet (202), a first magnetic flux detection element (204), a
second magnetic flux detection element (206), a logic circuit (208) and a power
supply regulator (210).
In accordance with an embodiment of the present invention, the magnet
12
(202) has conventional properties with strong axial field strength. Further, the
magnet (202) is placed at the lower end of the gear shift lever and is capable to
generate effective magnetic flux while coming in contact with the gear shift lever.
Also, the magnet (202) has high tensile strength to stand by heavy work load
5 during gear select operation.
In accordance with an embodiment of the present invention, the first
magnetic flux detection element (204) and the second magnetic flux detection
element (206) are configured to detect magnetic flux generated by the magnet
10 (202). Further, the first magnetic flux detection element (204) and the second
magnetic flux detection element (206) are, but not limited to, hall sensor and vary
their output levels based on the value of the magnetic flux generated by the
magnet (202).
15 In accordance with an embodiment of the present invention, the logic
circuit (208) is, but not limited to, a NAND logic circuit and comprises of, but not
limited to, two MOSFETs. Further, the logic circuit (208) facilitates redundancy
request in case of malfunctioning andlor failure of the first magnetic flux detection
element (204) and the second magnetic flux detection element (206). In other
20 words, in case of failure/malfunctioning of the magnetic andlor electrical
components the gear shift lever position sensor (200) will provide a specific output
i.e, neutral position instead of any arbitrary output and avoid any confusion to the
In accordance with an embodiment of the present invention, a power
supp!y regulator (210) is configured to provide power to the first magnetic flux
5 detect~on element (204), the second magnetic flux detection element (206) and
the logic circuit (208). Further, the power supply regulator (210) is connected with
a first power source (212). Also, the power supply regulator (210) is connected
with a second power source (214).
10 In accordance with an embodiment of the present invention, the first
power source (212) is a battery installed in a vehicle. Further, the second power
source (214) receives power from Electronic Control Unit (ECU) of the vehicle.
Figure 3 illustrates the process flow (300) of a method for continuous
15 position sensing of the gear shift lever by using the gear shift lever position sensor
(200) in accordance with yet another preferred embodiment of the present
invention.
At step 302, the magnet (202) generates magnetic flux in response to the
20 movement of the gear shift lever.
At step 304, the first magnetic flux detection element (204) and the
second magnetic flux detection element (206) generates different output levels in
accordance with the magnetic flux generated by the magnet (202).
14
At step 306, if voltage at the first magnetic flux detection element (204) is
'low' then the gear shift lever is in reverse position. In this case, voltage at the
second magnetic flux detection element (206) and the logic circuit (208) is 'high'.
5
At step 308, if voltage at the second magnetic flux detection element
(206) is 'low' then the gear shift lever is in drivelmanual mode position. In this case,
voltage at the first magnetic flux detection element (204) and the logic circuit (208)
is 'high'.
10
At step 310, if voltage at the first magnetic flux detection element (204)
and the second magnetic flux detection element (206) is 'high' then the logic
circu~t (208) generates low voltage. The low voltage at the logic circuit (208)
signifies that the gear shift lever is in neutral position. Further, the logic circuit
15 (208) will also generate low voltage in case of malfunctioning andlor failure of the
first magnetic flux detection element (204) and the second magnetic flux detection
element (206) and communicate the same to ECU in order to eliminate undesired
trans3iission.
2 0 Figure 4 is an exemplary illustration of a bit pattern chart (400)
corresponding to the method for continuous position sensing of gear shift lever
position by using the gear shift lever position sensor (200). It is apparent from the
figure 4 that when both the bits are high '1' at the first magnetic flux detection
15
element (204) and the second magnetic flux detection element (206) then the bit
corresponding to the logic circuit (208) is low '0'a nd detects the neutral position of
the gear shift lever. Further, reverse position of the gear shift lever is detected
when both the bits are high ' I ' at the logic circuit (208) and at the second magnetic
5 flux de!ection element.(206) and the bit corresponding to the first magnetic flux
detection element (204) is low '0'
The bit corresponding to the second magnetic flux detection element
(206) is low '0' and both the bits are high '1' at the first magnetic flux detection
10 element (204) and the logic circuit (208) then the gear shift lever is in drive or
manual mode position.
Figure 5 is an exemplary illustration of the PCB layout (500) of the gear
shift lever pos~tions ensor of figure 2. As shown in figure 5, the first magnetic flux
15 detection element (204), the second magnetic flux detection element (206) and
the log;c circuit (208) are placed on the PCB board and generate outputs in
respect of the gear shift lever position.
The above-mentioned gear shift lever position sensor besides
20 continuously position sensing of gear shift lever prevents overlap of the magnetic
flux detection by the first magnetic flux detection element and the second
~nag~erfilucx detection element. Since, the first magnetic flux detection element
and the second magnetic flux detection element are placed at a distance in the
sensor and have a logic circuit in between possibility of undesired reading is
remole. Further, the gear shift lever posit~ons ensor is compact in size and less
expensive as compared to existing position sensors having three or more
detection elements. Also, the presence of the logic circuit in the gear .shift lever
position sensor enables to provide positon sensing data accurately and timely to
5 the ECU which in turn efficiently actuate the transmission of the vehicle. In
addition to the aforesaid advantages, the disclosed logic circuit generates an
output in case of any failure and/or malfunction of magnetic/electrical components
and communicate the same to ECU in order to avoid undesired transmission.
Hence the proposed gear shift lever position sensor continuously detects the
10 position/s of the gear shift lever irrespective of the functioning of various
components and stands as reliable product for the vehicles.
The exemplary implementation described above is illustrated with specific
shapes. dimensions, and other characteristics, but the scope of the invention
15 includes various other shapes, dimensions, and characteristics. For example, the
magnet, magnetic flux detection elements etc. could be of particular shape and of
appropriate sizes for any particular combination of various parts of the gear shift
assembly. Further, the logic circuit may employ any other logic and is not limited to
NAND logic. Also, the placement of the gear shift lever position sensor in the
20 gearbox may vary in accordance with structural requirements. Also, the
compoiients as descr~bed above could be manufactured in various other ways
and .could include various other materials, including various other plastics and
also various metals
Similarly, the exemplary implementations described above include
specific examples of magnet, magnetic flux detection elements, logic circuits,
5 gearbox, gear shift lever positions etc. but any other appropriate parts, alone or in
combination, could be employed.
Various modifications to these embodiments are apparent to those skilled
rn the art from the description and the accompanying drawings. The principles
10 associated with the various embodiments described herein may be applied to
other embodiments. Therefore, the description is not intended to be limited to the
embodiments shown along with the accompanying drawings but is to be provided
broadest scope consistent with the principles and the novel and inventive features
disclosed or suggested herein. Accordingly. the invention is anticipated to hold on
15 to all cther such alternatives, modifications, and variations that fall within the
scope of the present invention and appended claims

We claim:
1. A gear shift lever position sensor (200)
comprising:
a magnet (202);
5 a first magnetic flux detection element (204);
a second magnetic flux detection element (206);
a logic circuit (208);
wherein said magnet (202) generates magnetic flux in accordance with
plurality of gear shift lever positions;
10 wherein said first magnetic flux detection element (204) and said second
magnetic flux detection element (206) generate output levels based on said
magnet~cfl ux generated by said magnet (202)
wherein said logic circuit (208) is provided between said first magnetic flux
detection element (204) and said second magnetic flux detection element (206)
15 wherein said plurality of gear shift lever positions comprises a reverse
position, a neutral pos~tiona, drive posit~ona nd a manual mode position.
2. The gear shift lever position sensor (200) as claimed in claim 1,
wherein said first magnetic flux detection element (204) and second magnetic flux
20 detection element (206) are hall sensors.
3. The gear shift lever position sensor (200) as claimed in claim 1,
wherein said logic circuit (208) is a NAND logic circuit.
25 4. The gear shift lever position sensor (200) as claimed in claim 1,
19
wherein said first magnetic flux detection element (204) is configured to detect
said reverse position of said gear shift lever
5. The gear shift lever position sensor (200) as claimed in claim 1,
5 wherein said second magnetic flux detection element (206) is configured to detect
said drive position of said gear shift lever
6. The gear shift lever position sensor (200) as claimed in claim 1,
wherein said second magnetic flux detection element (206) is configured to detect
10 said manual mode position of said gear shift lever.
7. 1-he gear shift lever position sensor (200) as claimed in claim 1,
wherein said logic circuit (208) is configured to detect said neutral position of said
gear shift lever.