Claims:WE CLAIM:
1. An arrangement (200) for coupling a gear (206a, 206b) to a shaft (208), said arrangement (200) comprising:
a. a shaft (208) defined by a cylindrical body having a plurality of spline grooves (214) configured along the length thereof;
b. at least one gear (206a, 206b) mounted on said shaft (208), said gear (206a, 206b) having a finger (207) extending from an operative engaging surface thereof; and
c. a hub (204) having a plurality of internal splines (212) configured on an operative inner wall of said hub (204) for facilitating slidable mounting of said hub (204) on said shaft (208), and a plurality of external splines (210) configured on an operative outer wall of said hub (204), said external splines (210) configured to mesh with said finger (207) for transmitting power from said shaft (208) to said gear (206a, 206b).
2. The coupling arrangement (200) as claimed in claim 1, wherein said hub (204) is a twin-gear (206a, 206b) coupling hub (204) configured to be engaged with gears (206a, 206b) mounted on said shaft (208) on either sides of said hub (204).
3. The coupling arrangement (200) as claimed in claim 1, wherein said spline grooves (214) are spaced apart from each by a predetermined distance ranging from 90mm to 95 mm.
4. The coupling arrangement (200) as claimed in claim 1, wherein distance between said external splines (210) and said finger (207) varies between 67mm to 75 mm.
5. The coupling arrangement (200) as claimed in claim 1, wherein the depth of each spline groove ranges from 3 mm to 3.5mm.
6. The coupling arrangement (200) as claimed in claim 1, wherein the diameter of said hub (204) ranges between 62mm and 67mm.
7. The coupling arrangement (200) as claimed in claim 1, wherein said shaft (208) is of a stress relieved material.
8. The coupling arrangement (200) as claimed in claim 6, wherein said shaft (208) is of case hardened steel.
9. A vehicle having an arrangement (200) for coupling a shaft (208) to a gear (206a, 206b) as claimed in any of the preceding claims.

Dated this 24th Day of March, 2022

_______________________________
MOHAN RAJKUMAR DEWAN, IN/PA – 25
of R.K.DEWAN & CO.
Authorized Agent of Applicant

TO,
THE CONTROLLER OF PATENTS
THE PATENT OFFICE, AT CHENNAI , Description:FIELD
The present disclosure relates to coupling arrangements of transmission shafts.
BACKGROUND
The background information herein below relates to the present disclosure but is not necessarily prior art.
Typically, a transmission system of a vehicle includes a gear coupling arrangement configured to facilitate transmission of torque and power from a transmission shaft to one or more gears. The conventional coupling arrangement comprises a hub on which a coupler is mounted. The hub has grooves configured thereon to allow nesting of the hub on a splined shaft. The splines of the shaft facilitate sliding displacement of the hub along the length of the shaft. The coupler is provided with external splines that enable coupling thereof with the teeth of the gears.
One of the issues faced by the conventional coupling arrangement is that both the hub and coupler being separate components need frequent lubrication. Further it is required that the arrangement should be aligned properly. Improper alignment of the coupler and the hub can significantly cause parasitic losses, and thereby lead to wear and tear of the gear teeth and the splines of the shaft due to increased friction, and increased fuel consumption rates. Hence, frequent assessment of the coupling arrangement is desired.
Moreover, combining the two elements of the hub and the coupler requires consumes more space, thereby making it bulky and costlier. Further, since the hub and the coupler are different elements, the strength and the load carrying capacity is significantly reduced, which can lead to fracture thereof at high torque requirements. Additionally, forging splines along the length of the shaft adds to the manufacturing cost and consumes additional space. To compensate for the overall cross-sectional diameter of the shaft, the overall diameter of the hub and the coupler (combined) is about 55 mm, which results in lesser load carrying capacity.
There is, therefore felt a need of an arrangement that alleviates the aforementioned drawbacks.
OBJECTS
Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows:
An object of the present disclosure is to provide an arrangement for coupling a gear to a shaft.
Another object of the present disclosure is to provide an arrangement for coupling a gear to a shaft which has a compact configuration.
Yet another object of the present disclosure is to provide an arrangement for coupling a gear to a shaft which requires relatively less maintenance.
Still another object of the present disclosure is to provide an arrangement for coupling a gear to a shaft which requires less number of components.
An object of the present disclosure is to provide an arrangement for coupling a gear to a shaft which is cost effective.
Another object of the present disclosure is to provide an arrangement for coupling a gear to a shaft which prevents parasitic losses.
Other objects and advantages of the present disclosure will be more apparent from the following description, which is not intended to limit the scope of the present disclosure.
SUMMARY
The present disclosure provides an arrangement for coupling a gear to a shaft. The arrangement comprises a shaft, at least one gear mounted on the shaft and a hub. The shaft is defined by a cylindrical body having a plurality of grooves configured along the length thereof. The gears are mounted on the shaft. The gear has a finger extending from an operative engaging surface thereof. The hub has a plurality of internal splines configured on an operative inner wall of the hub for facilitating slidable mounting of the hub on the shaft. The hub further has a plurality of external splines configured on an operative outer wall of the hub. The external splines are configured to mesh with the finger for transmitting power from the shaft to the gear.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
An arrangement, of the present disclosure, for coupling a gear to a shaft will now be described with the help of the accompanying drawing, in which:
Figure 1 and Figure 2 illustrate cross-sectional views of a conventional coupling arrangement;
Figure 3 shows an isometric view of the arrangement of the present disclosure;
Figure 4 shows an isometric view of a hub of the arrangement of Figure 3;
Figures 5 shows an isometric view of a shaft of the arrangement of Figure 3;
Figure 6a shows a cross-sectional view of the arrangement, wherein the hub is in neutral position;
Figure 6b shows a cross-sectional view of the arrangement, wherein the hub is engaged with the right gear; and
Figure 6c shows a cross-sectional view of the arrangement, wherein the hub is engaged with the left gear.
LIST OF REFERENCE NUMERALS
102 coupler and fork of a conventional coupling arrangement
104 hub of the conventional coupling arrangement
106 gear of the conventional coupling arrangement
108 transmission shaft of the conventional coupling arrangement
200 coupling arrangement of the present disclosure
204 hub
207 finger
208 shaft
210 external spline
212 internal spline
214 spline grooves
206a, 206b gear
216 bush
218 circlip
DETAILED DESCRIPTION
Embodiments, of the present disclosure, will now be described with reference to the accompanying drawing.
Embodiments are provided so as to thoroughly and fully convey the scope of the present disclosure to the person skilled in the art. Numerous details are set forth, relating to specific components, and methods, to provide a complete understanding of embodiments of the present disclosure. It will be apparent to the person skilled in the art that the details provided in the embodiments should not be construed to limit the scope of the present disclosure. In some embodiments, well-known processes, well-known apparatus structures, and well-known techniques are not described in detail.
The terminology used, in the present disclosure, is only for the purpose of explaining a particular embodiment and such terminology shall not be considered to limit the scope of the present disclosure. As used in the present disclosure, the forms “a”, “an” and “the” may be intended to include the plural forms as well, unless the context clearly suggests otherwise. The terms “comprises”, “comprising”, “including” and “having” are open-ended transitional phrases and therefore specify the presence of stated features, steps, operations, elements, modules, units and/or components, but do not forbid the presence or addition of one or more other features, steps, operations, elements, components, and/or groups thereof. When an element is referred to as being “mounted on”, “engaged to”, “connected to” or “coupled to” another element, it may be directly on, engaged, connected or coupled to the other element. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed elements.
Terms such as “inner”, “outer”, “beneath”, “below”, “lower”, “above”, “upper” and the like, may be used in the present disclosure to describe relationships between different elements as depicted from the figures.
A transmission system of a vehicle includes a gear coupling arrangement configured to facilitate transmission of torque and power from a transmission shaft (108) to one or more gears (106). The gear coupler comprises a hub (104) on which a coupler (102) is mounted. The conventional hub (104) has grooves configured thereon to allow nesting of the hub (104) on a splined shaft (108). As illustrated in Figure 1 and Figure 2, the splines of the shaft (108) facilitate sliding displacement of the hub (104) along the length of the shaft (108). The coupler (104) is provided with teeth that enable transmission of power from the shaft (108) to the gears (106) when engaged with the teeth of the gears (106).
One of the issues faced by the conventional coupling arrangement is that both the hub (104) and coupler (102) being separate components need frequent lubrication in the area therebetween. Further, improper alignment of the coupler (102) and the hub (104) can significantly cause parasitic losses, and thereby lead to wear and tear of the gear (106) teeth and the splines of the shaft (108) due to increased friction, and increased fuel consumption rates. Therefore frequent assessment of the alignment is required.
Moreover, combining the two elements of the hub (104) and the coupler (102) requires consumes more space, thereby making it bulky and uneconomical. Also, since the hub (104) and the coupler (102) are different elements, the strength and the load carrying capacity is significantly reduced, which can lead to fracture thereof at high torque requirements.
Additionally, forging splines along the length of the shaft (108) adds to the manufacturing cost in addition to consuming larger footprint. To compensate for the overall cross-sectional diameter of the shaft (108), the diameter of the coupler (102) and the hub (104) (combined) is reduced to about 55 mm, which results in lesser load carrying capacity.
There is, therefore felt a need of an arrangement that alleviates the aforementioned drawbacks.
An arrangement (200), of the present disclosure, for coupling a gear (206a, 206b) to a shaft (208) will now be disclosed with reference to Figure 3 through Figure 6c.
The arrangement (200) comprises a shaft (208) and at least one gear (206a, 206b) mounted on the shaft (208). The shaft (208) is defined by a cylindrical body having a plurality of spline grooves (214) configured along the length thereof. The gear (206a, 206b) is mounted on the shaft (208). The gear (206a, 206b) has a finger (207) extending from an operative engaging surface thereof. The arrangement (200) further comprises a hub (204) having a plurality of internal splines (212) and a plurality of external splines. The internal splines (212) are configured on an operative inner wall of the hub (204) for facilitating slidable mounting of the hub (204) on the shaft (208). The plurality of external splines (210) is configured on an operative outer wall of the hub (204). The external splines (210) are configured to mesh with the finger (207) for transmitting power from the shaft (208) to the gear (206a, 206b).
In an embodiment, the hub (204) is a twin-gear (206a, 206b) coupling hub (204) configured to be engaged with gears (206a, 206b) mounted on the shaft (208) on either sides of the hub (204). The twin-gear configuration of the hub (204) enables mounting of a fork (202) on the hub (204) to facilitate displacement of the hub (204).
In another embodiment, the spline grooves (214) are spaced apart from each by a predetermined distance ranging from 90mm to 95mm.
In yet another embodiment, distance between said external splines (210) and said finger (207) varies between 67mm to 75 mm.
In still another embodiment, the depth of each groove ranges from 3 mm to 3.5mm.
In one embodiment, the diameter of the hub (204) ranges between 62mm and 67mm. The relatively larger diameter of the hub (204) (as compared to the conventional coupling and hub (204) arrangement (200)) allows increase in the load carrying capacity of the hub (204) significantly.
In an embodiment, the shaft (208) is of a stress relieved material which helps in enhancing the load carrying capacity. In another embodiment, the shaft (208) is of case hardened steel.
The present disclosure further describes a vehicle having an arrangement (200) for coupling a shaft (208) to a gear (206a, 206b) as claimed in any of the preceding claims. In an embodiment, the vehicle is a tractor.
In a working configuration, the arrangement (200), of the present disclosure, is mounted on a transmission system of a tractor having a PTO shaft (208) coupled to an equipment. The system has a pair of gears (206a, 206b) mounted one on the left side and the other on the right side of the shaft (208). It is desired that the gear (206a, 206b) on the left side is engaged when high efficiency of fuel consumption is required when the power transmission is in economic mode. Conversely, it is desired that the gear (206a, 206b) on the right side is engaged during high torque applications.
As shown in Figure 6a, the hub (204) is in its neutral position i.e., not in engaged position with either of the gears (206a, 206b). When it is desired to couple the right side gear (206a, 206b) or the left side gear (206a, 206b) with the shaft (208), the hub (204) is slid along the shaft (208) to either right side (as shown in Figure 6b) or left side (as shown in Figure 6b) to engage with the finger (207) of the respective gears (206a, 206b). The sliding of the hub (204) is enabled by the internal splines (212) of the hub (204) nested in the spline grooves (214) of the shaft (208).
The configuration of the arrangement (200) contributes to the cost cutting of manufacturing of the transmission shaft (208) and the hub (204) by at least 60%, by not only eliminating the need of separate elements of the coupler and the hub (204), but also removing the need for splines along the length of the shaft (208). Further, the parasitic losses which were caused due to conventional coupling arrangements are eliminated by the arrangement (200) of the present disclosure, thereby leading to relatively higher fuel efficiency.
The foregoing description of the embodiments has been provided for purposes of illustration and not intended to limit the scope of the present disclosure. Individual components of a particular embodiment are generally not limited to that particular embodiment, but, are interchangeable. Such variations are not to be regarded as a departure from the present disclosure, and all such modifications are considered to be within the scope of the present disclosure.
TECHNICAL ADVANCEMENTS
The present disclosure described hereinabove has several technical advantages including, but not limited to, the realization of an arrangement for coupling a gear to a shaft, that:
• is cost effective;
• is compact and occupies less space;
• prevents parasitic losses;
• has more load carrying capacity; and
• is efficient.
The foregoing disclosure has been described with reference to the accompanying embodiments which do not limit the scope and ambit of the disclosure. The description provided is purely by way of example and illustration.
The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
The foregoing description of the specific embodiments so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.
Any discussion of documents, acts, materials, devices, articles or the like that has been included in this specification is solely for the purpose of providing a context for the disclosure. It is not to be taken as an admission that any or all of these matters form a part of the prior art base or were common general knowledge in the field relevant to the disclosure as it existed anywhere before the priority date of this application.
While considerable emphasis has been placed herein on the components and component parts of the preferred embodiments, it will be appreciated that many embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other changes in the preferred embodiment as well as other embodiments of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation.