FORM 2
THE PATENTS ACT 1970
[39 OF 1970]
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
[See section 10; rule 13]
TITLE: “A SYNCHRONIZER RING GEAR FOR A TRANSMISSION ASSEMBLY AND A TRANSMISSION ASSEMBLY THEREOF”
Name and Address of the Applicant:
TATA MOTORS LIMITED; an Indian company having its registered office at Bombay House, 24 Homi Mody Street, Hutatma Chowk, Mumbai – 400 001, Maharashtra, India.
Nationality: Indian
The following specification particularly describes the invention and the manner in which it is to be performed.

TECHNICAL FIELD
Present disclosure, in general, relates to a field of automobiles. Particularly, but not exclusively, the present disclosure relates to a transmission assembly of a Vehicle. Further, embodiments of the present disclosure relate to a synchronizer ring gear for the transmission assembly.
BACKGROUND OF THE DISCLOSURE
Vehicles are equipped with a gearbox which is connected to a flywheel of an engine via a clutch to transmit controlled torque to wheels of the vehicle. Generally, two types of gearboxes have been predominantly used, namely a manual gearbox and an automatic gearbox. The manual gearbox requires an operator to shift between gears, while the automatic gearbox changes gears based on vehicle operating conditions or other prerequisite parameters.
Typically, gear shifting in the manual gearbox, requires effort and skill from an operator. The operator needs to gauge and operate a shift lever in a cabin of the vehicle, along with operation of a clutch for shifting to the required gear and in-turn regulate movement of the vehicle. This requires coordinated movement of the limbs of the user along with being able to determine other vehicle operating parameters. Movement of the shift lever in the predefined pattern results in a linear displacement of a connecting member such as a shift cable or shifting rod connecting the shift lever and the gearbox, which is transmitted to the gearbox to facilitate shifting of gears. In general, manual transmission assemblies include synchronizers to bring gears to the same speed prior to engagement. Such synchronizer simplifies the gear change process and prevents the need for 'double de-clutching'. The synchronizer is a ring device that is disposed between the driving gear and the synchronizer hub and acts through friction to equalize the speeds of the main shaft and the desired drive gear.
Conventionally, synchronizer rings are of two types i.e., synchronizer ring that is integral with the gear and the synchronizer ring with welded/splined means to mesh with gears. Of the two types, the synchronizer ring integral with gear is the least

expensive and most preferred, where length of the gearbox is not a concern. Further, the shifter sleeve stoppers are provided by a gear face when a gear diameter is greater than shifter sleeve. However, when the gear diameter is smaller than a dog teeth/shifter sleeve, the gear face cannot be used as stopper. In such cases, the stopper is provided on the synchro ring or the synchro ring is separated and is welded/splined to the gear with a plate in between, which is complicated and expensive.
The present disclosure is directed to overcome one or more limitations stated above or any other limitations associated with the conventional mechanisms.
The drawbacks/difficulties/disadvantages/limitations of the conventional techniques explained in the background section are just for exemplary purpose and the disclosure would never limit its scope only such limitations. A person skilled in the art would understand that this disclosure and below mentioned description may also solve other problems or overcome the other drawbacks/disadvantages of the conventional arts which are not explicitly captured above.
SUMMARY OF THE DISCLOSURE
One or more shortcomings of the prior art are overcome by a synchronizer ring gear and a transmission assembly as claimed and additional advantages are provided through the synchronizer ring gear and the transmission assembly as claimed in the present disclosure. Additional features and advantages are realized through the techniques of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered a part of the claimed disclosure.
In one non-limiting embodiment of the present disclosure a synchronizer ring gear is disclosed. The synchronizer ring gear comprises a gear portion defined with a plurality of gear teeth. The synchronizer ring gear includes a synchronizer ring integrally defined on the gear portion. The synchronizer ring is defined with a plurality of dog teeth and a plurality of slots defined along a circumference of the

synchronizer ring. The plurality of slots are formed in a spaced apart configuration to receive a plurality of teeth of a shifter sleeve.
In an embodiment, diameter of the gear portion is smaller than diameter of the synchronizer ring.
In an embodiment, the synchronizer ring is configured with a predefined width to accommodate a portion of the plurality of teeth of the shifter sleeve.
In an embodiment, each slot is defined extending circumferentially along a portion of the synchronizer ring.
In an embodiment, each slot of the plurality of slots extends along a predetermined length of circumference of the synchronizer ring.
In an embodiment, the predetermined length corresponds to portion of teeth of the shifter sleeve received when the shifter sleeve is engaged with the Synchronizer ring gear.
In an embodiment, the plurality of slots are radially spaced apart at a predetermined angle in a range of 60 to 180 degrees.
In another non-limiting embodiment of the present disclosure, a transmission assembly is disclosed. The transmission assembly comprises at least one synchronizer ring gear. The synchronizer ring gear comprises a gear portion defined with a plurality of gear teeth. The synchronizer ring gear includes a synchronizer ring integrally defined on the gear portion. The synchronizer ring is defined with a plurality of dog teeth and a plurality of slots defined along a circumference of the synchronizer ring. The plurality of slots are formed in a spaced apart configuration to receive a plurality of teeth of a shifter sleeve. The transmission assembly comprises at least one shifter fork and at least one shifter sleeve. The at least one shifter sleeve is slidably disposed on at least one gear shaft and is adapted to engage with the at least one synchronizer ring gear on

displacement by the at least one shifter fork. The plurality of slots of the synchronizer ring are configured to receive the plurality of teeth of the at least one shifter sleeve on engagement of the at least one shifter sleeve with the at least one synchronizer ring gear.
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 ACCOMPANYING DRAWINGS
The novel features and characteristic of the disclosure are set forth in the appended claims. The disclosure itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying figures. One or more embodiments are now described, by way of example only, with reference to the accompanying figures wherein like reference numerals represent like elements and in which:
Figure 1a is a perspective view of a transmission assembly depicting synchronizer ring gears and a shifter sleeve in neutral position , in accordance with an embodiment of the present disclosure.
Figure 1b is a perspective view of the transmission assembly depicting synchronizer ring gears, while the shifter sleeve in engaged position, in accordance with an embodiment of the present disclosure.
Figure 1c is a perspective view of the transmission assembly depicting a shifter fork, in accordance with an embodiment of the present disclosure.
Figure 2a is a perspective view of a synchronizer ring gear, in accordance with an embodiment of the present disclosure.

Figure 2b is a front view of the synchronizer ring gear, in accordance with an embodiment of the present disclosure.
Figure 2c is a front view of the synchronizer ring gear, in accordance with an embodiment of the present disclosure.
Figure 3 is a sectional top view of the transmission assembly, in accordance with an embodiment of the present disclosure.
The figures depict embodiments of the disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following description that alternative embodiments of the system and method illustrated herein may be employed without departing from the principles of the disclosure described herein.
DETAILED DESCRIPTION
While the embodiments in the disclosure are subject to various modifications and alternative forms, specific embodiment thereof has been shown by way of example in the figures and will be described below. It should be understood, however, that it is not intended to limit the disclosure to the particular forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternative falling within the scope of the disclosure.
The terms “comprises”, “comprising”, or any other variations thereof used in the disclosure, are intended to cover a non-exclusive inclusion, such that a synchronizer ring gear, transmission assembly, that comprises a list of components does not include only those components but may include other components not expressly listed or inherent to such system, or assembly, or device. In other words, one or more elements in a system proceeded by “comprises… a” does not, without more constraints, preclude the existence of other elements or additional elements in the system or method.
Embodiments of the present disclosure discloses a transmission assembly. The transmission assembly comprises at least one synchronizer ring gear. The

synchronizer ring gear comprises a gear portion defined with a plurality of gear teeth. The synchronizer ring gear includes a synchronizer ring integrally defined on the gear portion. The synchronizer ring is defined with a plurality of dog teeth and a plurality of slots defined along a circumference of the synchronizer ring. The plurality of slots are formed in a spaced apart configuration to receive a plurality of teeth of a shifter sleeve. The transmission assembly comprises at least one shifter fork and at least one shifter sleeve. The at least one shifter sleeve is slidably disposed on at least one gear shaft and is adapted to engage with the at least one synchronizer ring gear on displacement by the at least one shifter fork. The plurality of slots of the synchronizer ring are configured to receive the plurality of teeth of the at least one shifter sleeve on engagement of the at least one shifter sleeve with the at least one synchronizer ring gear. With such configuration, the transmission assembly may reduce expenses involved with the synchronizer ring and further, structural modification of transmission assembly required to provide stopper for shifter sleeve in transmission assembly may be minimized or eliminated.
The disclosure is described in the following paragraphs with reference to Figures 1a to 3. In the figures, the same element or elements which have same functions are indicated by the same reference signs. It is to be noted that, the vehicle is not illustrated in the figures for the purpose of simplicity. One skilled in the art would appreciate that the system and the method as disclosed in the present disclosure may be used in any vehicle including but not liming to commercial vehicles, and passenger vehicles, and the like. The system and the method of the present disclosure may also be implemented in vehicles having manual transmission or automatic transmission, for suitably maneuvering the vehicle without deviating from the principles of the present disclosure.
Figures 1a to 1c refer to an exemplary embodiment of the present disclosure which illustrates a transmission assembly (200). The transmission assembly (200) may include a gearbox [not shown explicitly in figures] which is operatively connectable to an engine [not shown explicitly in figures] of the vehicle. The gearbox may include an input shaft connectable to the engine and an output shaft connectable to

a plurality of wheels [not seen in figures] of the vehicle, where the input shaft and the output shaft may be rotatably engaged through the plurality of gears. The gearbox may include at least one lay shaft connectable between the input shaft and the output shaft. In an embodiment, the plurality of gears includes at least one synchronizer ring gear (100). The synchronizer ring gear (100) is disposable on one of the input shaft, the output shaft and the lay shaft. The transmission assembly (200) includes at least one shifter fork (4) as can be seen in Figure 1c and at least one shifter sleeve (3) slidably disposed on at least one gear shaft. The shifter sleeve (3) is configured to receive a portion of the shifter fork (4) and is adapted to engage with the at least one synchronizer ring gear (100) on displacement by the at least one shifter fork (4). In an embodiment, the shifter sleeve (3) is configured to engage with the synchronizer ring gear (100) to vary speed/torque output from the gearbox of the vehicle as can be seen in Figure 1b.
Referring now to Figures 2a and 2b, the synchronizer ring gear (100) includes a gear portion (1) defined with a plurality of gear teeth (11) on an outer surface. The plurality of gear teeth (11) are configured to mesh with teeth of a meshing gear of the plurality of gears to transmit torque. The synchronizer ring gear (100) includes a synchronizer ring (2) integrally defined on the gear portion (1) as can be clearly seen in Figure 2a. The synchronizer ring (2) is defined on an end of the synchronizer ring gear (100) receivable by the shifter sleeve (3) for engagement. In an embodiment, the diameter of the gear portion (1) is smaller than diameter of the synchronizer ring (2) as can be clearly seen in Figure 2c.
The synchronizer ring (2) is defined with a plurality of dog teeth (21) extending radially from the gear portion (1) in a spaced apart configuration. The spaced apart configuration of the dog teeth (21) is configured to allow engagement of the adjacent gear with the synchronizer ring gear (100). The plurality of dog teeth (21) are configured to engage with the adjacent gear while shifting gears by displacement of the shifter sleeve (3) to engage the adjacent gear. In an embodiment, the dog teeth (21) are configured to engage with the adjacent gear to

allow smooth transition between gears in the gearbox during displacement of the shifter sleeve (3) by the shifter fork (4).
Referring again to Figures 2a and 2b, the synchronizer ring (2) is defined with a plurality of slots (22) defined along a circumference of the synchronizer ring (2). In an embodiment, each slot is defined to extend circumferentially along a portion of the synchronizer ring (2). In the illustrative embodiment, the slots (22) are defined by removing one or more teeth of the dog teeth (21) to define the slots (22) as can be clearly seen in Figure 2a. For sake of explanation, the shape of the slots (22) is defined as a rectangular slot and the same shall not be construed as a limitation. The shape of the slots (22) may be varied based on the profile and number of teeth (31) of the shifter sleeve (3) to be received by each slot. In the illustrative embodiment, configuration of the synchronizer ring (2) with the slots (22) is depicted in the synchronizer ring gear (100), where the synchronizer ring (2) is integrally defined on the gear portion (1). Such configuration of the synchronizer ring (2) shall not be limited to the synchronizer ring gear (100), and may also be utilized in individual synchronizer rings, where the synchronizer ring (2) is separately coupled to gears of the transmission assembly (200) by welding, brazing and the like.
The plurality of slots (22) are formed in a spaced apart configuration on the synchronizer ring (2) to receive a plurality of teeth (31) of the shifter sleeve (3). Each slot of the plurality of slots (22) extends along a predetermined length of circumference of the synchronizer ring (2) to accommodate a predetermined number of teeth (31) of the shifter sleeve (3) on engagement of the shifter sleeve (3) with the synchronizer ring (2) as can be seen in Figure 3. In an embodiment, the predetermined length of the slots (22) corresponds to portion of teeth (31) of the shifter sleeve (3) received when the shifter sleeve (3) is engaged with the synchronizer ring gear (100). For sake of explanation, the predetermined number of teeth (31) accommodated in the slot is depicted as two and the same shall not be construed as a limitation. Further, the length of each slot may be varied based on predetermined number of teeth (31) to be accommodated and based on design requirements.

Referring back to Figures 2a and 2b, the plurality of slots (22) are radially and equidistantly spaced apart at a predetermined angle in a range of 90 to 180 degrees based on the number of slots (22). For the sake of explanation, the number of slots (22) are illustrated as three slots (22) radially spaced apart equidistantly on the circumference of the synchronizer ring (2) with the predetermined angle being 120 degrees and the number may be varied based on the configuration of the shifter sleeve (3) and design requirements of the synchronizer ring (2). In an embodiment, the plurality of slots (22) may be randomly spaced in a spaced apart configuration based on the configuration of the plurality of teeth (31) of the shifter sleeve (3). In such a random configuration, two slots (22) may be spaced proximal to each other, while another slot may be spaced away from the two slots (22). In an embodiment, the synchronizer ring (2) is configured with a predefined width to accommodate a portion of the plurality of teeth (31) of the shifter sleeve (3). The slots (22) and the predetermined width of the synchronizer ring (2) define the width of the slots (22), where a portion of the synchronizer ring (2) at the end of each slot functions as a stopper to stop the teeth (31) of the shifter sleeve (3) from further sliding on engagement of the shifter sleeve (3) with the synchronizer ring (2). Such configuration of the transmission assembly (200) may reduce expenses involved with the synchronizer ring (2). Further, structural modification of transmission assembly (200) required to provide stopper for shifter sleeve (3) in transmission assembly (200) may be minimized or eliminated.
Referring back to figures 1a and 1b in conjunction with Figure 3, the slots (22) of the synchronizer ring (2) are vacant, when the shifter sleeve (3) is not engaged with the synchronizer ring gear (100). Upon displacement of the shifter sleeve (3) by the shifter fork (4), a portion of the teeth (31) of the shifter sleeve (3) are received by the slots (22) of the synchronizer ring (2) as can be seen in Figure 3. In Figure 3, portion of the synchronizer ring (2) at the end of each slot functions as a stopper to stop the teeth (31) of the shifter sleeve (3) from further sliding on engagement of the shifter sleeve (3) with the synchronizer ring (2). Such configuration eliminates

need for an additional stopper arrangement which requires structural modifications to the shifter sleeve (3), and other components of the transmission assembly (200).
In an embodiment, the synchronizer ring gear (100) may reduce expenses involved with a separate synchronizer ring (2).
In an embodiment, the synchronizer ring (2) may be implemented easily in any transmission assembly (200) by varying the gear configuration and eliminates requirement of additional stopper plate between the gear and the synchronizing ring.
In an embodiment, the synchronizer ring (2) may be manufactured within short time, and requires minimal modifications to the synchronizer ring gear (100).
EQUIVALENTS
With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity.
It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims are generally intended as “open” terms. 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”; 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. 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 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 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.”
In addition, where features or aspects of the disclosure are described in terms of Markush groups, those skilled in the art will recognize that the disclosure is also thereby described in terms of any individual member or subgroup of members of the Markush group.
While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.

Reference numerals:

Component Reference numeral
Synchronizer ring gear 100
Transmission assembly 200
gear portion 1
Gear teeth 11
Synchronizer ring 2
Plurality of dog teeth 21
Plurality of slots 22
Shifter sleeve 3
Plurality of teeth 31
Shifter fork 4

We claim:
1. A synchronizer ring gear (100) for a transmission assembly (200) of a
vehicle, the synchronizer ring gear (100) comprising:
a gear portion (1) defined with a plurality of gear teeth (11); and a synchronizer ring (2) integrally defined on the gear portion (1), the synchronizer ring (2) is defined with a plurality of dog teeth (21), a plurality of slots (22) defined along a circumference of the synchronizer ring (2) wherein the plurality of slots (22) are formed in a spaced apart configuration to receive a plurality of teeth (31) of a shifter sleeve (3).
2. The synchronizer ring gear (100) as claimed in claim 1, wherein diameter of the gear portion (1) is smaller than diameter of the synchronizer ring (2).
3. The synchronizer ring gear (100) as claimed in claim 1, wherein the synchronizer ring (2) is configured with a predefined width to accommodate a portion of the plurality of teeth (31) of the shifter sleeve (3).
4. The synchronizer ring gear (100) as claimed in claim 3, wherein each slot is defined extending circumferentially along a portion of the synchronizer ring (2).
5. The synchronizer ring gear (100) as claimed in claim 4, wherein each slot of the plurality of slots (22) extends along a predetermined length of circumference of the synchronizer ring (2).
6. The synchronizer ring gear (100) as claimed in claim 5, wherein the predetermined length corresponds to portion of teeth of the shifter sleeve (3) received when the shifter sleeve (3) is engaged with the Synchronizer ring gear (100).
7. The synchronizer ring gear (100) as claimed in claim 1, wherein the plurality of slots (22) are radially spaced apart at a predetermined angle in a range of 60 to 180 degrees.

8. A transmission assembly (200) for a vehicle, the assembly (200) comprising;
at least one synchronizer ring gear (100) comprising:
a gear portion (1) defined with a plurality of gear teeth (11); and a synchronizer ring (2) integrally defined on the gear portion (1), the synchronizer ring (2) is defined with a plurality of dog teeth (21), a plurality of slots (22) defined along a circumference of the synchronizer ring (2), wherein the plurality of slots (22) are formed in a spaced apart configuration to receive a plurality of teeth (31) of at least one shifter sleeve (3); at least one shifter fork (4);
at least one shifter sleeve (3) is slidably disposed on at least one gear shaft and is adapted to engage with the at least one synchronizer ring gear (100) on displacement by the at least one shifter fork (4); and
wherein the plurality of slots (22) of the synchronizer ring (2) are configured to receive the plurality of teeth (31) of the at least one shifter sleeve (3) on engagement of the at least one shifter sleeve (3) with the at least one synchronizer ring gear (100).