The present subject matter described herein, relates to a transmission casing for a vehicle. More particular, to a transmission casing having an internal differential wall to reduce the sealed volume of the transmission casing.
BACKGROUND
[0002] A transmission assembly is primarily provided in a vehicle to route the power created by an engine to driving wheels of the vehicle. Further, the transmission assembly manipulates the engine's output to make sure RPM and Torque are available to the wheels in desired driving range. Typically, as shown in FIG. 1A, a transmission assembly has a transmission casing 100 primarily designed to accommodate an input shaft assembly, a counter shaft assembly and a differential assembly. The transmission casing 100 is generally a two part assembly having a right case 102 and a left case 104 assembled together to form the transmission casing 100. The right case 102 of the transmission casing 100 is assembled to an engine (not shown). The left case 104 of the transmission casing 100 is assembled to the right case. Plurality of bosses are provided on the outer periphery of the right case 102 and the left case 104 to facilitate integration of the right case 102 and the left case 104, via bolts, together forming the transmission casing 100.
[0003] Referring to FIGS. 1B and 1C illustrating top view and isometric view, respectively, of the left case 104 of the transmission casing 100 according to an existing art. To accommodate an input shaft, an aperture 104A is provided in the left case 104. Adjacent to the aperture 104A, an aperture 104B is provided to accommodate a countershaft. Apart from the apertures 104A, 104B, an aperture 104C is provided in a differential region

106 of the left case 104 to accommodate a differential assembly and its bearing. A plurality of bosses 108 are provided at an outer periphery of the left case 104 to accommodate bolts which facilitates in integration of the left case 104 with the right case 102 of the transmission casing 100. The transmission casing 100 thus creates a hollow casing having definite volume. A plurality of ribs 110 originating from the aperture 104C towards the bosses 108 are also provided across the periphery of the differential region 106. An outer differential wall 112 acts as a base of the left case 104 in the differential region 106.
[0004] Power created by an engine's crankshaft is first received by the input shaft in the transmission casing 100. The counter shaft is provided parallel to the input shaft and is driven by the input shaft. Transmission gears are provided on the input shaft and the counter shaft. The differential is the final component that carries the power out of the transmission assembly and on to the wheels of the vehicle. A set of transmission gears parallel to those on the counter shaft is arranged along the differential assembly. Lubrication oil is provided in the transmission casing 100 to reduce the friction, heat, and wear between mechanical components that are in contact with each other. A minimum amount of lubrication oil is required to be maintained inside the transmission casing 100 for smooth working of the mechanical components.
[0005] Under loading condition, i.e., during driving the vehicle, the differential assembly which is provided in the differential region 106 of the left case 104 of the transmission casing 100 is under excessive load. The outer differential wall 112 and the plurality of ribs 110 ensures that the excessive load during loading condition is distributed evenly in the differential region 106 of the left case 104 of the transmission casing 100. Also, pyramid shaped structures 113 are formed on the external differential wall 112 of the transmission casing 100 to provide mechanical strength to the structure of the differential region 106. However, under

loading condition, the sizable amount of lubrication oil, which is provided inside sealed transmission casing 100, imparts hindrance to the rotation of gears and shafts due to its accumulation in deep pockets 114 (FIG. 1D) formed on internal differential wall 116 (FIG. 1D) of the left case 104. These deep pockets with excess oil entrapped or present in them114 causes oil churning loss and in turn deteriorates the mechanical efficiency of the gear system in the transmission casing 100. Also, by having the deep pockets 114, extra lubrication oil is required to fill these deep pockets 114, which results into increase in the overall weight of the transmission casing 100. Since lubrication oil is an essential part of the working of the transmission casing, it is not possible to completely eliminate the hindrance to the rotation of gears and shafts in transmission casing 100. Furthermore, the internal differential wall 116 of the left case 104 of the transmission casing 100 is designed to effectively distribute the excessive load. Any change in the alignment or configuration of the internal differential wall may weaken the structural integrity of the transmission casing 100. This weak integration may lead to a crack in casing or leakage of oil which may cause seizure of mechanical components inside transmission casing 100.
[0006] Therefore, there is need in the art to provide a transmission casing 100 which ensures use of less quantity of oil and better distribution of bearing load over the differential region 106 of the transmission casing 100.
OBJECTS OF THE DISCLOSURE
[0007] It is therefore an object of the present subject matter to overcome the aforementioned and other drawbacks in existing transmission casing of the transmission assembly.

[0008] The principal objective of the present subject matter is to provide a transmission casing with reduced sealed volume.
[0009] Another object of the present subject matter is to provide a transmission casing which warrant less quantity of lubrication oil owning to the reduced sealed volume.
[0010] Another object of the present subject matter is to provide a transmission casing which improves the efficiency of the transmission assembly.
[0011] Yet another object of the present subject matter is to provide a transmission casing which ensures better distribution of bearing load over a differential region of the transmission casing.
[0012] These and other objects and advantages of the present subject matter will be apparent to a person skilled in the art after consideration of the following detailed description taken into consideration with accompanying drawings in which preferred embodiments of the present subject matter are illustrated.
SUMMARY
[0013] One or more drawbacks of conventional transmission casing are overcome, and additional advantages are provided through the transmission as claimed in the present disclosure. Additional features and advantages are realized through the technicalities of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered to be a part of the claimed disclosure.
[0014] The present subject matter describes a transmission casing of a vehicle. The transmission casing includes a right case and a left case integrated with the right case forming a sealed volume. The left case of the transmission casing includes a differential region having an internal

differential wall defining a volume with inner periphery of the left case in the differential region. In an aspect, the internal differential wall is having continuous flat surface.
[0015] In an aspect, the transmission casing includes a shift tower region between a power input region and the differential region.
[0016] In an aspect, the differential region having an external differential wall. The external differential wall includes at least two strengthening ribs joining the shift tower region to the external differential wall.
[0017] In an aspect, a first rib of the at least two strengthening ribs is positioned at a converging angle to a second rib of the at least two strengthening ribs.
[0018] It is to be understood that the aspects and embodiments of the disclosure described above may be used in any combination with each other. Several of the aspects and embodiments may be combined to form a further embodiment of the disclosure.
[0019] The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] It is to be noted, however, that the appended drawings illustrate only typical embodiments of the present subject matter and are therefore not to be considered for limiting of its scope, for the invention may admit to other equally effective embodiments. The detailed description is described with reference to the accompanying figures. In the figures, a reference number identifies the figure in which the reference number first appears.

The same numbers are used throughout the figures to reference like features and components. Some embodiments of system or methods or structure in accordance with embodiments of the present subject matter are now described, by way of example, and with reference to the accompanying figures, in which:
[0021] FIG. 1A illustrates a perspective view of a transmission casing according to an existing art;
[0022] FIG. 1B illustrates illustrating a top view of a left case of the transmission casing according to an existing art;
[0023] FIG. 1C illustrates isometric view of the left case of the transmission casing according to the existing art;
[0024] FIG. 1D illustrates an internal view of the left case of the transmission casing according to the existing art;
[0025] FIG. 2 illustrates an internal view of a left case of a transmission casing according to one of the embodiments of the present subject matter;
[0026] FIG. 3A illustrates illustrating top view of the left case of the transmission casing according to one of the embodiments of the present subject matter; and
[0027] Fig. 3B illustrates isometric view of the left case of the transmission casing according to one of the embodiments of the present subject matter.
[0028] The figures depict embodiments of the present subject matter for the purposes of illustration only. A person skilled in the art will easily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.
DETAILED DESCRIPTION

[0029] The detailed description of various exemplary embodiments of the disclosure is described herein with reference to the accompanying drawings. It should be noted that the embodiments are described herein in such details as to clearly communicate the disclosure. However, the amount of details provided herein is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the scope of the present disclosure as defined by the appended claims.
[0030] It is also to be understood that various arrangements may be devised that, although not explicitly described or shown herein, embody the principles of the present disclosure. Moreover, all statements herein reciting principles, aspects, and embodiments of the present disclosure, as well as specific examples, are intended to encompass equivalents thereof.
[0031] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises", "comprising", "includes" and/or "including", when used herein, specify the presence of stated features, integers, steps, operations, elements and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and/or groups thereof.
[0032] It should also be noted that in some alternative implementations, the functions/acts noted may occur out of the order noted in the figures. For example, two figures shown in succession may, in fact, be executed concurrently or may sometimes be executed in the reverse order, depending upon the functionality/acts involved.
[0033] Unless and otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly

understood by one of ordinary skill in the art to which example embodiments belong. It will be further understood that terms, e.g., those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
[0034] These and other advantages of the present subject matter would be described in greater detail with reference to the following figures. It should be noted that the description merely illustrates the principles of the present subject matter. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described herein, embody the principles of the present subject matter and are included within its scope.
[0035] The present subject matter describes a transmission casing with reduced sealed volume.
[0036] Referring to FIG. 2 illustrating top view of an internal side of a left case 104 of a transmission casing 100, according to one of the embodiments of the present subject matter. The left case 104 has a differential region 106 wherein a differential assembly is provided to carry the power out of the transmission assembly and on to the wheels of the vehicle. The differential region 106 is the region where load from the differential assembly is released into the transmission casing 100. An aperture 104C is provided in the differential region 106 to accommodate the differential assembly and its bearing. A differential bearing is provided in the aperture to associate the differential assembly with the aperture 104C. The load from the differential assembly is transferred to the differential bearing and the differential bearing in turn transfers the load in the differential region 106 to the transmission casing 104.
[0037] In an aspect, the differential region 106 includes an internal differential wall 116 defining a volume with an inner periphery of the left

case 104 in the differential region 106. The internal differential wall 116 associated with the differential region 106 is having a continuous flat surface 202. In other words, the internal differential wall 116 is smoothened from inside of the left case 104 of the transmission casing 100 and the internal differential wall 116 is moved closer to a flange 204 provided at an outer periphery of the left case 104 in the differential region 106. As a result, the internal differential wall 116 reduces the inner sealed volume of the transmission casing 100. The reduction in sealed volume reduces the requirement of quantity of lubrication oil inside the transmission casing 100. Thus, the hindrance observed by the rotating shafts and gears by the lubrication oil is considerably reduced, which in turn reduces the oil churning losses. The reduction of oil churning losses increases the transmission power thereby resulting into an enhanced fuel efficiency.
[0038] Referring to FIG. 3A-3B illustrating top view and isometric view of the left case 104 of the transmission casing 100, respectively, according to one of the embodiments of the present subject matter. It may be observed from FIG. 3A that the internal differential wall 116 is smoothened (as shown in FIG. 2) into a flat continuous surface 202.
[0039] To compensate for such increase in mass and to maintain the existing alignment or configuration of the internal differential wall 116 of the left case 104, the pyramid shaped structures 113 present in the existing external differential wall 112 are removed and replaced by at least two strengthening ribs joining 304, 306 joining a shift tower region 302 to the external differential wall 112. Moreover, one strengthening rib 304 of the at least two strengthening ribs 304 306 is added at a converging angle to another strengthening rib 306. In an example, but not limited to, the converging angle may range from 5 to 20 degrees depending on the segment of the vehicle for which the transmission casing 100 is designed.

In a preferred aspect, the converging angle may range from 10 to 12 degrees.
[0040] In an aspect, the strengthening ribs 304, 306 impart rigidity and robustness to the differential region 106 that were reduced due to the removal of the pyramid shaped structures 113 present in the existing design.
[0041] Thus, with the proposed modification to the left case 104 of the transmission casing 100, by forming the flat continuous structure 202 in the internal differential wall 116 and by incorporation of the strengthening ribs 304, 306 in the external differential wall 112 of the left case 104, not only the consumption of lubricating oil is minimized but also rigidity and robustness has been induced into the transmission casing 100.
TECHNICAL ADVANTAGES
[0042] The proposed transmission casing has reduced sealed volume which reduces the quantity of lubrication oil. The less quantity of lubrication oil reduces the cost as well as hindrance observed by the rotating parts. Further, the less quantity of lubrication oil reduces the overall weight of the transmission assembly. Reduced hindrance increases the efficiency of the transmission assembly. Also the proposed transmission casing ensures better distribution of load over the differential region of the transmission casing.
Equivalents
[0043] It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as "open" terms (e.g., the term "including" should be interpreted as "including but not limited to", the term "having" should be interpreted as "having at least", the term

"includes" should be interpreted as "includes but is not limited to", etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases "at least one" and "one or more" to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles "a" or "an" limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases "one or more" or "at least one" and indefinite articles such as "a" or "an" (e.g., "a" and/or "an" should typically be interpreted to mean "at least one" or "one or more"); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of "two recitations," without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to "at least one of A, B, and C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B, and C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances, where a convention analogous to "at least one of A, B, or C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B, or C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C

together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase "A or B" will be understood to include the possibilities of "A" or "B" or "A and B."
[0044] It will be further appreciated that functions or structures of a plurality of components or steps may be combined into a single component or step, or the functions or structures of one-step or component may be split among plural steps or components. The present invention contemplates all of these combinations. Unless stated otherwise, dimensions and geometries of the various structures depicted herein are not intended to be restrictive of the invention, and other dimensions or geometries are possible. In addition, while a feature of the present invention may have been described in the context of only one of the illustrated embodiments, such feature may be combined with one or more other features of other embodiments, for any given application. It will also be appreciated from the above that the fabrication of the unique structures herein and the operation thereof also constitute methods in accordance with the present invention. The present invention also encompasses intermediate and end products resulting from the practice of the methods herein. The use of "comprising" or "including" also contemplates embodiments that "consist essentially of or "consist of the recited feature.
[0045] Although embodiments for the present subject matter have been described in language specific to structural features, it is to be understood that the present subject matter is not necessarily limited to the specific features described. Rather, the specific features and methods are disclosed as embodiments for the present subject matter. Numerous modifications and adaptations of the system/component of the present

invention will be apparent to those skilled in the art, and thus it is intended by the appended claims to cover all such modifications and adaptations which fall within the scope of the present subject matter.

WE CLAIM

1. A transmission casing (100) of a vehicle, comprising:
a right case (102); and
a left case (104) integrated with the right case (102) forming a sealed volume, wherein the left case (104) comprises:
a differential region (106) having an internal differential wall (116) defining a volume with an inner periphery of the left case (104) in the differential region (106), wherein the internal differential wall (116) is having continuous flat surface (202).
2. The transmission casing (100) as claimed in claim 1, comprising a shift tower region (302) formed between a power input region and the differential region (106).
3. The transmission casing (100) as claimed in claim 2, wherein the differential region (106) having an external differential wall (112), and wherein the external differential wall (112) comprises at least two strengthening ribs (304, 306) joining the shift tower region (302) to the external differential wall (112).
4. The transmission casing (100) as claimed in claim 3, wherein a first rib (304) of the at least two strengthening ribs (304, 306) is positioned at a converging angle to a second rib (306) of the at least two strengthening ribs (304, 306).