TECHNICAL FIELD
Embodiments of the present invention relate generally to gear shifting mechanism in an automobile and more specifically to a detent mechanism for a vehicular transmission.
BACKGROUND ART 5
All vehicular transmissions such as manual transmission, automated manual transmission and automatic transmission are controlled through a gear shift lever. The gear shift lever or simply called as gear shifter is generally a metal lever attached to a shift assembly of the transmission. The gear shifter allows the vehicle to be put into different 10 gears. In an automated manual transmission and automatic transmission, the gear shifter is known as a gear selector. The gear shifter is normally located between the two front seats of the vehicle. A gear knob is provided at the top of the gear shifter, and includes a shift pattern that guides the gear selection in a manual transmission. The shift pattern indicates which 15 way the gear shifter should be moved when selecting a certain gear.
A manual gearbox is the type of transmission that allows the driver to select the gear through the gear shifter. The driver need to push the clutch pedal, which disengages the gearbox from the engine and movement is provided to the gear shifter in order to achieve a desired gear 20 ratio, and the clutch is released. Thus, for shifting a gear a gearbox disengagement from the engine is required in manual transmission. The automated manual transmission is an automatic gearbox which does not change gears automatically but helps or facilitates manual gear changes without the need to depress the clutch pedal manually. All the work of 25 changing gears is done by electronic sensors, processors and actuators to engage the gears based on the input from the driver or by a computer.
The automatic transmission is a type of gearbox which automatically changes the gear ratios, it allows an internal combustion
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engine to provide speed and torque outputs necessary for the vehicle movement. The automatic gearboxes are connected to the engine by a torque converter, so no clutch is required in automatic gearboxes.
The problem that occurs with the gear shifter is that the gear shifter tends to develop a free play in the movement of the gear shifter. Figure 1 5 illustrates a gear shifting mechanism (100), in accordance with an embodiment of the prior art. As shown in figure 1, the gear shifter (102) is disposed into a pivot ball (104). The gear shifter (102) with pivot ball (104) is free to rotate on two spherical seats (106) provided on two opposite sides of the pivot ball (104). Thus, there is no restriction in the movement of 10 the gear shifter. As there is no fixed position of the gear shifter (102), therefore the gear shifter develops a free play. The free play creates a sense of looseness of the gear shifter (102) while shifting from one gear to other and the driver does not get a feel or sense that the gear has been shifted. So, feeling of gear shifting is required while driving so that the 15 driver does not have to look towards the gear shifter (102) while driving.
Therefore, in light of the discussion above, there is need for an improved gear shifter which does not suffer from above mentioned deficiencies.
OBJECT OF THE INVENTION 20
An aspect of the present invention discloses a detent mechanism for a vehicular transmission.
Another aspect of the present invention discloses a detent mechanism that removes the free play from the gear shifter.
Yet another aspect of the present invention discloses a detent 25 mechanism for a vehicular transmission that provides a feeling of gear shifting to a driver.
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SUMMARY OF THE INVENTION
Embodiments of the present invention aim to provide a detent mechanism for a vehicular transmission. The detent mechanism removes looseness or free play in the gear shifter and stabilizes the gear shifter at a fixed position. Also, while shifting the gear the detent mechanism provides 5 a feel of gear shifting to the driver. Moreover, the detent mechanism is provided in a compact block, thus the mechanism is settled in a confined space.
According to first aspect of the present invention, a detent mechanism for a vehicular transmission is disclosed. The detent 10 mechanism comprises a gear shifter, a pivot ball coupled with the gear shifter, a detent block containing a detent profile disposed below the pivot ball and a detent plunger loaded with a spring disposed above the detent block. Further, the detent plunger and the spring are disposed in a cavity provided in a portion of the gear shifter inside the pivot ball. Further, the 15 spring is configured to allow the movement of the detent plunger on the detent profile of the detent block.
In accordance with an embodiment of the present invention, the vehicular transmission is a manual transmission.
In accordance with an embodiment of the present invention, the 20 spring is provided between the gear shifter and the detent plunger.
In accordance with an embodiment of the present invention, the detent plunger is adapted to follow the detent profile for shifting from a third gear to a fourth gear.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS 25
So that the manner in which the above recited features of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may have been referred by
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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, for the invention may admit to other equally effective embodiments. 5
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 a gear shifting mechanism, in accordance with an 10 embodiment of the prior art;
Fig. 2A illustrates a detent mechanism, in accordance with an embodiment of the present invention; and
Fig. 2B illustrates different positions of a gear shifter on a detent profile, in accordance with an embodiment of the present invention. 15
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
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, and are not intended to represent the scale of the 20 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 detailed description thereto are not intended to limit the invention to the particular form disclosed, but 25 on the contrary, the invention is to cover all modifications, equivalents, and alternatives falling within the scope of the present invention as defined by the appended claim. As used throughout this description, the word "may" is
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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" mean "at least one” and the word “plurality” means “one or more” unless otherwise mentioned. Furthermore, the terminology and phraseology used herein is solely used for descriptive purposes and should 5 not be construed as 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, integers or steps. Likewise, the 10 term "comprising" is considered synonymous with the terms "including" or "containing" for applicable legal purposes. Any discussion of documents, acts, materials, devices, articles and the like is included in the specification solely for the purpose of providing a context for the present invention. It is not suggested or represented that any or all of these matters form part of 15 the prior art base or were common general knowledge in the field relevant to the present invention.
In this disclosure, whenever a composition or 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 20 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 elements and vice versa.
The present invention is described hereinafter by various embodiments with reference to the accompanying drawing, wherein 25 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 and should not be construed as limited to the embodiment set forth herein. Rather, the embodiment is provided so that this disclosure will be thorough and complete and will fully convey the 30
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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 5 of the implementations. These materials are to be treated as exemplary, and are not intended to limit the scope of the invention.
Referring to the drawings, the invention will now be described in more detail. Figure 2A illustrates a detent mechanism (200), in accordance with embodiment of the present invention. The detent mechanism (200) is 10 provided with a gear shift mechanism in a vehicular transmission. In accordance with one embodiment of the invention, the vehicular transmission is a manual transmission. In accordance with another embodiment of the invention, the vehicular transmission may be an automatic transmission. Further, the detent mechanism (200) comprises a 15 gear shifter (202). The gear shifter (202) is a metal rod coupled with the gear shifting mechanism for manually shifting the gears.
The detent mechanism further comprises a pivot ball (204). The pivot ball (204) is made of a tough thermoplastic material. For increasing the toughness of the pivot ball (204), the thermoplastic material may be 20 reinforced with glass fibres. In accordance with one embodiment of the invention, the pivot ball (204) may be of metal. The pivot ball (204) is coupled with the gear shifter (202). In one embodiment of the invention, the gear shifter (202) is disposed into the pivot ball (204) by means of threads. The pivot ball (204) includes external threads and the gear shifter (202) 25 includes external threads. Thus, the gear shifter (202) is coupled with the pivot ball (204) by screwing the gear shifter (202) into the pivot ball (204).
In accordance with another embodiment of the invention, the gear shifter (202) is locked inside the pivot ball (204) by means of a locking pin
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(not shown in figure). The locking pin is inserted tangentially inserted into the gear shifter (202) through the pivot ball (204). The locking pin arrests the movement of the gear shifter (202) with respect to the pivot ball (204).
The detent mechanism (200) further comprises a detent block (206). In one embodiment of the invention, the detent block (206) is a 5 metallic component. Preferably the detent block (206) is of made up of an aluminium alloy. In various embodiments, alloying elements include one or more of, but not limited to, silicon, iron, copper, manganese, magnesium, nickel, titanium and strontium. Moreover, the detent block (206) may be fabricated using a variety of manufacturing processes such as casting, 10 hot/cold forging and pressure die casting etc. In accordance with another embodiment of the invention, the material of the detent block (206) may be of cast iron. For the purpose of this specification, “cast iron” is a group of iron-carbon alloys with carbon content greater than 2%. Also, Carbon ranging from 1.8–4 wt.% and silicon are the main alloying elements of cast 15 iron.
Further, the detent block (206) is disposed below the pivot ball (204). The detent block (206) contains a detent profile (208). The shape of the detent profile (208) may be in the form of wave having at least a crest and a trough portion. The detent mechanism (200) further comprises a 20 detent plunger (210) with a spring (212). The detent plunger (210) is disposed above the detent block (206). Also, the detent plunger (210) is disposed in to a cavity (214) provided in the gear shifter (202) inside the pivot ball (204). Additionally, the spring (212) is provided between the gear shifter (206) and the detent plunger (210). The spring (212) provides a stiff 25 contact between the detent plunger (210) and detent profile (208), which means, the spring (212) tends to push the detent plunger (210) against the detent profile (208).
Also, the detent plunger (210) is configured move on the detent
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profile (208), while shifting the gears. Figure 2B illustrates the position of gear shifter (202) on the detent profile (208), in accordance with embodiment of the invention. As shown in figure 2B, the spring (212) is configured to allow the movements of the detent plunger (210) on the detent profile (208) of the detent block (206). In accordance, with 5 embodiment of the invention, the detent plunger (210) is adapted to follow the detent profile (208) for shifting the transmission from a third gear to a fourth gear. In accordance with an embodiment of the invention, the detent plunger (210) may be used for shifting the transmission from one particular gear to any other gear. 10
In use, the driver holds the gear shifter (202) and moves the gear shifter (202) for shifting a gear. Subsequently, the detent plunger (210) which is disposed in the gear shifter (202) starts to moves on the detent profile (208). That is, when the detent plunger (210) moves either in forwards or backward direction, the spring (212) contracts itself and allows 15 the movement of the detent plunger (208) on the crest of the detent profile (208). Thereby, the detent plunger (208) is unable to rest on the crest region, due to the detent profile (208) at the crest region. Thus, the detent plunger (210) is shifted to the trough region of the detent profile (208). In this position, the spring (212) expands and allows resting of the detent 20 plunger (210) at the trough region of the detent profile (208). This means, the detent plunger (210) can rest on the trough region only. Therefore, fixed position is assigned to the gear shifter (202) by the detent plunger (210).
Also, the provision of spring (212) and the detent profile (208) provides a shift feel to the driver. The assigning of definite location of rest to 25 the gear shifter (202) through detent plunger (210) removes the free play and looseness, while shifting the gears. Further, the detent plunger (210) is disposed inside the pivot ball (204) and thus compactness is provided to the detent mechanism (200). Therefore, the disposing of detent plunger (210) inside the pivot ball (204) leads to restricting of the detent mechanism 30
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(200) in a confined space.
Various modifications to these embodiments are apparent to those skilled in the art from the description and the accompanying drawings. The principles associated with the various embodiments described herein may be applied to other embodiments. Therefore, the description is not intended 5 to be limited to the embodiments shown along with the accompanying drawings but is to be providing broadest scope of consistent with the principles and the novel and inventive features disclosed or suggested herein. Accordingly, the invention is anticipated to hold on to all other such alternatives, modifications, and variations that fall within the scope of the present invention and appended claims.

We Claim:
1. A detent mechanism (200) for a vehicular transmission, comprising:
a gear shifter (202);
a pivot ball (204) coupled with the gear shifter (202); 5
a detent block (206) containing a detent profile (208) disposed below the pivot ball (204); and
a detent plunger (210) loaded with a spring (212) disposed above the detent block (206);
wherein the detent plunger (210) and the spring (212) are 10 disposed in a cavity provided in the gear shifter (202), inside the pivot ball (204); and
wherein the spring (212) is configured to allow the movement of the detent plunger (210) on the detent profile (208) of the detent block (206). 15
2. The detent mechanism (200) as claimed in claim 1, wherein the vehicular transmission is a manual transmission.
3. The detent mechanism (200) as claimed in claim 1, wherein the spring (212) is provided between the gear shifter (202) and the detent plunger (210) 20
4. The detent mechanism (200) as claimed in claim 1, wherein the detent plunger (210) is adapted to follow the detent profile (208) for shifting from a third gear to a fourth gear.