FIELD OF INVENTION:
[001] The present subject matter described herein, relates to a transmission assembly of a vehicle. More particular, to a transmission casing of a transmission assembly having angular differential wall to reduce the sealed volume of the transmission casing.
BACKGROUND OF THE INVENTION:
[002] A transmission assembly is primarily provided in a vehicle to route the power created by 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, a transmission assembly has a transmission casing primarily designed to accommodate an input shaft assembly, a counter shaft assembly and a differential assembly. The transmission casing is generally a two part assembly having a right case and a left case assembled together to form the transmission casing. The right case of the transmission casing is assembled to the engine. The left case of the transmission casing is assembled to the right case. Plurality of bosses are provided on the outer periphery of the right case and the left case to facilitate integration of the right case and left case, via. Bolts, together forming the transmission casing assembly.
[003] Referring to figure 1a and 1b illustrating top view and isometric view, respectively, of a left case of a transmission casing assembly according to an existing art. To accommodate an input shaft, an aperture 101a is provided in the left case 100. Adjacent to the aperture 101a, an aperture 101b is provided to accommodate a counter shaft. Apart from the apertures 101a, 101b, an aperture 101c is provided in differential region 102 of the left case 100 to accommodate a differential assembly and its bearing. A plurality of bosses 103 are provided at the outer periphery of the left case 100 to accommodate bolts which facilitates in integration of left case 100 with right case (not shown) of the transmission casing assembly. The transmission casing assembly thus creates a hollow casing having definite volume. A plurality of ribs 104 originating from the aperture 101c towards the bosses 103 are also provided across the periphery of the differential region. A differential wall 105 acts as a base of left case 100 in the differential region 102.
[004] Power created by the engine’s crankshaft is first received by the input shaft in the transmission casing. 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 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 for smooth working of the mechanical components.
[005] Under loading condition i.e. during driving the vehicle, the differential assembly which is provided in the differential region 102 of the left case 100 of the transmission casing is under excessive load. The differential wall 105 and the plurality of ribs 104 ensures that the excessive load during loading condition is distributed evenly in the differential region 102 of the left case 100 of the transmission casing. Further under loading condition, the sizable amount of lubrication oil which is provided inside the transmission casing, imparts hindrance to the rotation of gears and shaftsDue to this hindrance, the efficiency of the transmission assembly deteriorates. It also increases the overall weight of the transmission assembly. Since lubrication is an essential part of the working of the transmission assembly, it is not possible to completely eliminate the hindrance to the rotation of gears and shafts in transmission assembly. Furthermore, the differential wall 105 of the left case 100 of the transmission casing is designed to effectively distribute the excessive load. Any change in the alignment of the differential wall 105 of the left case 100 may result in weak integration of left case 100 with right case. This weak integration may lead to leakage of oil which may cause seizure of mechanical components inside transmission assembly
[006] Japanese Patent Application JP6105535B2 discloses a differential gear lubrication structure that lubricates bearing with a differential case that rotates inside a transmission case and a lubricating oil that is swept up by a final driven gear. The differential gear lubrication structure ensures the lubrication performance of the bearing that supports the differential case and the bearing that supports the transmission shaft while reducing the agitation resistance of the lubricating oil by the final drive gear provided in the differential case. Although, the patent application describes a differential gear lubrication structure which enables reduction in resistance by the lubricating oil, the lubrication structure is not capable of reducing the quantity of oil used inside the transmission casing.
[007] Therefore, there is need in the art to provide a transmission casing which ensures use of less quantity of oil and better distribution of bearing load over the differential region of the transmission casing.
OBJECTS OF THE INVENTION:
[008] 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.
[009] The principal objective of the present subject matter is to provide a transmission casing with angular differential wall for reduced sealed volume.
[0010] Another object of the present subject matter is to provide a transmission casing which warrant less quantity of lubrication oil owning to reduced sealed volume.
[0011] Another object of the present subject matter is to provide a transmission casing which improves the efficiency of the transmission assembly.
[0012] Yet another object of the present subject matter is to provide a transmission casing which ensures better distribution of bearing load over the differential region of the transmission casing.
[0013] 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 OF THE INVENTION:
[0014] 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.
[0015] The present subject matter discloses a transmission casing assembly with angular differential wall for reduced sealed volume. The transmission casing assembly comprises a right case and a left case. The left case is with the right case to form a sealed volume. The left case of the transmission casing comprises an aperture, a differential wall, a plurality of bosses, a plurality of ribs and a circular rib. The aperture is provided in a differential region to accommodate a differential assembly and its bearing. The differential wall defines the contour of the base of the left case in the differential region. The differential wall is angularly oriented downwards with its first end originating from the aperture and its second end meeting the lower half of the plurality of bosses. The plurality of bosses are provided on a flange at the outer periphery of the left case in the differential region. The plurality of bosses are provided to accommodate bolts for facilitation of integration of the left case with the right case. Each of the plurality of ribs connects the outer periphery of the aperture with the plurality of bosses. The circular rib is provided to link each of the plurality of bosses, provided on the flange across the outer periphery of the left case in the differential region, with the adjacent bosses.
[0016] In an aspect, the aperture has a differential bearing socket in the form of a cylindrical cavity to accommodate differential bearing.
[0017] In an aspect, profile of the first end of the differential wall corresponds to the profile of the differential bearing socket of the aperture.
[0018] In an aspect, the second end of the differential wall is assembled with the lower end of the circular rib.
[0019] In an aspect, the circular rib has a flip-L profile.
[0020] In an aspect, the differential wall maintains an angular orientation in the range of 90o to 140o with respect to axis of the drive axle shaft ensuring no obstruction to the working of inner mechanical components of the transmission casing.
[0021] In an aspect, the circular rib links the upper part of the plurality of bosses for better distribution of excessive load.
[0022] In an aspect, the height of the plurality of ribs is equal to the height of the plurality of bosses to enhance load bearing capacity of the transmission casing.
[0023] In an aspect, the number of ribs are equal to the number of bosses provided on the flange at the outer periphery of the left case in the differential region.
[0024] In an aspect, the circular rib act as a junction between the plurality of ribs and the plurality of bosses.
[0025] 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.
[0026] 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
[0027] 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:
[0028] Fig. 1a illustrates illustrating top view of a left case of a transmission casing according to an existing art;
[0029] Fig. 1b illustrates isometric view of a left case of a transmission casing according to the existing art;
[0030] Fig. 2a illustrates illustrating top view of a left case of a transmission casing according to one of the embodiments of the present subject matter;
[0031] Fig. 2b illustrates isometric view of a left case of a transmission casing according to one of the embodiments of the present subject matter;
[0032] Fig. 3a illustrates cross-section view along X’-X’ of differential region of the left case according to one of the embodiments of the present subject matter; and
[0033] Fig. 3b illustrates cross-sectional view along Y’-Y’ of differential region of the left case according to one of the embodiments of the present subject matter.
[0034] 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.
DESCRIPTION OF THE PREFERRED EMBODIMENTS:
[0035] 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.
[0036] 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.
[0037] 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.
[0038] 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.
[0039] 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.
[0040] 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.
[0041] The present subject matter describes a transmission casing assembly with reduced sealed volume.
[0042] Referring to figure 2a and 2b illustrating top view and isometric view of a left case of a transmission casing, respectively, according to one of the embodiments of the present subject matter. The left case 200 has a differential region 202 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 202 is the region where load from the differential assembly is released into the transmission casing. An aperture 201 is provided in the differential region 202 to accommodate the differential assembly and its bearing. A differential bearing is provided in the aperture to associate the differential assembly with the aperture 201. To accommodate the differential bearing, a differential bearing socket 203 is provided in the transmission casing. The differential bearing socket 203 is in the form of a cylindrical cavity. The load from the differential assembly is transferred to the differential bearing and the differential bearing in turn transferred the load in the differential region 202 to the transmission casing.
[0043] The base of the left case 200 in the differential region has a differential wall 204. The differential wall 204 defines the contour of the base of the left case 200. A flange 205 is provided at the outer periphery of the left case 200 in the differential region 202.
[0044] A plurality of bosses 206 are provided on the flange 205 all across the outer periphery of the left case 200 in the differential region 202. The plurality of bosses 206 are designed to accommodate bolts. The plurality of bosses 206 facilitates the integration of the left case 200 with the right case forming a sealed volume. The integration of the left case 200 and right case results in the whole of the transmission casing assembly.
[0045] A plurality of ribs 207 are also provided over the differential wall 304 for better distribution of excessive load. The plurality of ribs 207 connects the outer periphery of the aperture 201 with the plurality of bosses 206 provided on the flange 205 all across the outer periphery of the left case 200 in the differential region 202. Thus, the number of ribs 207 are equal to the number of bosses 206 provided on the flange 205 all across the outer periphery of the left case 200 in the differential region 202. The height of the plurality of ribs 207 are maintained equal to the height of the plurality of bosses 206. This characteristic of the plurality of ribs 207 provide strength to the whole differential region 202 of the left case 200 by enhancing the load bearing capacity through equal distribution of excessive load.
[0046] The differential wall 204 provided in the differential region 202 of the left case 200 is angularly oriented downwards. The downward orientation of differential wall 204 reduces the inner sealed volume of the transmission casing assembly. The reduction in sealed volume reduces the requirement of quantity of lubrication oil inside the transmission casing assembly. Thus, the hindrance observed by the rotating shafts and gears by the lubrication oil is considerably reduced. However due to the angular orientation of the differential wall 204 a couple of unintended consequences occur. First, due to the angular orientation, the likelihood of the left case 200 slipping over the right case increases considerably under loading. Second, , due to load, mating flange of left and right case may lose contact resulting into flange opening. These two above mentioned scenarios may result in lubrication oil leakage. The leaking of lubrication oil may cause seizure of mechanical components inside transmission assembly . To avoid any such issue resulting from lubrication oil leakage, a circular rib 208, with flip L profile, is provided at the outer periphery of the left case 200 in the differential region 202. The circular rib 208 links each of the plurality of bosses 206, provided on the flange 205 across the outer periphery of the left case 200 in the differential region 202, with the adjacent bosses. The circular rib 208 links the upper part of the plurality of bosses 206 with the adjacent bosses. This provides better distribution of load around the outer periphery of the left case 200 resulting in the reduction in slipping of Transmission cases for effective sealing in order to eliminate oil leakage..
[0047] Referring to figure 3a and 3b illustrating cross-section view along X’-X’ and Y’-Y’ of differential region of the left case, respectively, according to one of the embodiments of the present subject matter. The differential wall 204 maintains an angular orientation a in the range of 90o to 140o with respect to axis of the axle drive shaft. The angular orientation a varies in this range depending on the position of the differential bearing in the left case 200 of the transmission casing. Further, the angular orientation a in this range ensures that the differential wall 204 does not obstruct the working of inner mechanical components of the differential casing. The differential wall 204 has a first end 301 and a second end 302. The first end 301 of the differential wall 204 originates from the aperture 201, continuing its orientation angularly downwards, with its second end 302 meeting the lower half of the plurality of bosses 206. Since the first end 301 of the differential wall 204 originates from the aperture 201, its profile corresponds to the differential bearing socket 203 of the aperture 201. The second end 302 of the differential wall 304 is assembled with the lower end of the circular rib 208 providing stiffness to the whole circular rib 208. The circular rib 208, the plurality of ribs 207 and the plurality of bosses 206 are connected to each other, such that, the circular rib 208 act as a junction between the plurality of ribs 207 and the plurality of bosses 206. The connection between the circular rib 208, the plurality of ribs 207 and the plurality of bosses 206 provides stiffness in the outer periphery region of the left case 200.
TECHNICAL ADVANTAGES
[0048] 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.
[0049] 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.”
[0050] 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.
[0051] 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 with angular differential wall for reduced sealed volume, the transmission casing comprises:
a right case; and
a left case (200) integrated with the right case forming a sealed volume, wherein the left case (200) of the transmission casing comprises:
an aperture (201), provided in a differential region (202), to accommodate a differential assembly;
a differential wall (204) defining the contour of the base of left case (200) in the differential region (202);
a plurality of bosses (206), provided on the flange (205) at the outer periphery of the left case (200) in the differential region (202), to accommodate bolts for facilitation of integration of the left case (200) with the right case; and
a plurality of ribs (207) connecting the outer periphery of the aperture (201) with the plurality of bosses (206),
characterized in that
the differential wall (204) is angularly oriented downwards, having its first end (301) originating from the aperture (201) and its second end (302) meeting the lower half of the plurality of bosses (206); and
a circular rib (208) to link, each of the plurality of bosses (206) provided on the flange (205) across the outer periphery of the left case (200) in the differential region (202), with the adjacent bosses.
2. The transmission casing as claimed in claim 1, wherein the aperture (201) has a differential bearing socket (203) in the form of a cylindrical cavity to accommodate differential bearing.
3. The transmission casing as claimed in claim 1 and 2, wherein profile of the first end (301) of the differential wall (204) corresponds to the profile of the differential bearing socket (203) of the aperture.
4. The transmission casing as claimed in claim 1, wherein the second end (302) of the differential wall (204) is assembled with the lower end of the circular rib (208).
5. The transmission casing as claimed in claim 4, wherein the circular rib (208) has a flip-L profile.
6. The transmission casing as claimed in claim 1, wherein the differential wall (204) maintains an angular orientation a in the range of 90o to 140o with respect to axis of the axle drive shaft ensuring no obstruction to the working of inner mechanical components of the transmission casing.
7. The transmission casing as claimed in claim 1, wherein the circular rib (208) links the upper part of the plurality of bosses (206) for better distribution of excessive load.
8. The transmission casing as claimed in claim 1, wherein the height of the plurality of ribs (207) is equal to the height of the plurality of bosses (206) to enhance load bearing capacity of the transmission casing.
9. The transmission casing as claimed in claim 1, wherein the number of ribs (207) are equal to the number of bosses (206) provided on the flange (205) at the outer periphery of the left case (200) in the differential region (202).
10. The transmission casing as claimed in claim 1, wherein the circular rib (208) act as a junction between the plurality of ribs (207) and the plurality of bosses (206).