Description:FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003

COMPLETE SPECIFICATION
[See section 10, Rule 13]

COVER FOR DIFFERENTIAL HOUSING OF A VEHICLE

MAHINDRA & MAHINDRA LIMITED, A COMPANY REGISTERED UNDER THE INDIAN COMPANIES ACT, 1913, HAVING ADDRESS AT MAHINDRA RESEARCH VALLEY (MRV), MAHINDRA WORLD CITY, PLOT NO.41/1, ANJUR P.O., CHENGALPATTU, KANCHIPURAM DISTRICT, TAMILNADU – 603004, INDIA

THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED.

TECHNICAL FIELD OF THE INVENTION:
[1] The present invention relates to a cover for differential housing of a vehicle for accommodating an axle gear. Also, the present invention relates to a flange for a cover.
BACKGROUND OF THE INVENTION:
[2] Generally, a differential gear system (also referred as a differential) is a mechanism that uses multiple gears to transmit power and control RPMs in both wheels connected to each side of a rear drive axle. In the conventional system, when a banjo axle is used, oil leakage frequently happens from joints between a body and a cover of the differential housing. When the cover is bolted with the body of differential housing, it is observed that clamping forces (which are exerted by a bolt when it is tightened) away from the bolts are often sub-optimal leading to oil leakage from the differential housing. Therefore, oil leakage from the rear drive axle vehicles is a widely recurring concern.
[3] Figure 1 shows a perspective view of a rear axle of a vehicle showing differential housing of the prior art. Further, figures 2 (a-c) shows a contour plot displacement analysis of the rear axle of Figure 1 under different load conditions. From Figures, 2 (a-c), it is observed that maximum displacement in the rear axle is concentrated/occurs on the differential housing. It is evident from Figures 2 (a-c) that the displacement in the differential housing increases with increase in the load on rear axle. Maximum displacement is observed in Figure 2 (c) i.e. 12.91 mm and minimum displacement is observed in Figure 2 (a) i.e. 2.5 mm. The displacement in the differential housing (100) may lead to development of stress or strain in the differential housing (100) and thereby prone to oil leakage therefrom.
[4] Therefore, there is a need to provide a cover for differential housing of a vehicle that overcomes the aforementioned problems.
SUMMARY OF THE INVENTION
[5] In an aspect, the present invention provides a cover for differential housing of a vehicle providing uniformity of sealing by reducing the contact opening between a body of the differential housing and the cover.
[6] The cover of the present invention comprises a recess, a flange around the periphery of the recess, a plurality of troughs provided on a contacting surface of the flange forming a plurality of crests on non-contacting surface of the flange correspondingly and a plurality of mounting holes for mounting the cover over the body of the differential housing. The recess accommodates a portion of the axle gear of a differential gear system. The troughs increase the stiffness of the cover and provide the uniformity of sealing by reducing the contact opening between a body and the cover of the differential housing.
[7] In accordance with the embodiments of the present invention, the plurality of troughs are provided away from the proximity of the plurality of mounting holes.
[8] In accordance with the embodiments of the present invention, the plurality of troughs are provided away from the proximity of the said plurality of mounting holes.
[9] In accordance with the embodiments of the present invention, each trough is formed at a central position on the surface of the flange.
[10] In accordance with the embodiments of the present invention, the depth of the trough is based on thickness of the flange and width of the trough depends on width of the flange. According to the present invention, a preferable ratio of a depth (D) to a width (W) of said trough (302) is in the range of 0.5:11 to 2:15.
[11] In accordance with the embodiments of the present invention, the plurality of troughs is provided between the mounting holes based on the stress analysis.
[12] In accordance with the embodiments of the present invention, the troughs are provided on the bottom side of the flange.
[13] In another aspect, the present invention also relates to a flange for a cover which imparts stiffness. The flange comprises a plurality of mounting holes and a plurality of troughs provided on a contacting surface of the flange forming crests on non-contacting surface of the flange correspondingly for increasing the stiffness of the flange.
BRIEF DESCRIPTION OF ACCOMPANYING DRAWING
[14] The detailed description is described with reference to the accompanying figures.
Figure 1 is a perspective view of a rear axle of a vehicle showing differential housing of the prior art;
Figure 2 is a contour plot illustrating displacement analysis of Figure 1 at different load conditions: a) 1G load showing maximum displacement of 2.5 mm, b) 2G load showing maximum displacement of 6.15 mm, and c) 3G load showing maximum displacement of 12.91 mm, of the prior art;
Figure 3 is a perspective view of a cover used for differential housing of a vehicle, in accordance with the present invention;
Figure 4 is a cross-sectional view of a cover of Figure 3, in accordance with the present invention;
Figure 5 is a detailed cross-sectional view of section C (trough) showed in Figure 4, in accordance with the present invention;
Figure 6 (a) is a front view of a cover used for a differential housing of a vehicle in the prior art;
Figure 6 (b) is a computer-aided engineering (CAE) simulation analysis of Figure 6 (a);
Figure 7 (a) is a front view of a cover used for the differential housing of a vehicle, in accordance with the present invention;
Figure 7 (b) is a computer-aided engineering (CAE) simulation analysis of Figure 7 (a) (iteration 1);
Figure 8 (a) is a front view of a cover used for differential housing of a vehicle showing that that the mounting holes location at bottom left hand side of figure 7 (a) is shifted towards left side by 14 mm, in accordance with the present invention; and
Figure 8 (b) is a computer-aided engineering (CAE) simulation analysis of Figure 8 (a) (iteration 2).
DETAILED DESCRIPTION OF THE INVENTION:
[15] The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of the invention as defined by the description. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. In addition, descriptions of well-known functions and constructions are omitted for clarity and conciseness.
[16] The terms and words used in the following description are not limited to the bibliographical meanings but are merely used by the inventor to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of the present invention is provided for illustration purpose only.
[17] It is to be understood that the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise.
[18] The present invention discloses a cover for differential housing of a vehicle for accommodating an axle gear which provides uniformity of sealing and reduces the contact opening between the body and the cover of the differential housing.
[19] Referring to the Figures 3-5 of the drawings, a cover (100) for differential housing (1000) of a vehicle for accommodating an axle gear is provided in accordance with the embodiments of the present invention. The cover (100) comprises a recess (200), a flange (300) around the periphery of the recess (200) and a plurality of troughs and correspondingly a plurality of crests (302B). The recess (200) accommodates a portion of an axle gear of a differential gear system. A plurality of mounting holes (301) is provided on the surface of the flange (300). The plurality of troughs (302) is provided on a contacting surface (300A) of the flange (300) that forms the plurality of crests on non-contacting surface (300B) of the flange (300) correspondingly. The troughs (302) increase the stiffness of the cover (100) and provide the uniformity of sealing by reducing the contact opening between a body (101) and the cover (100) of the differential housing (1000).
[20] In accordance with the embodiments of the present invention, the plurality of troughs (302) are provided away from the proximity of the plurality of mounting holes (301). In an alternative embodiment, the minimum distance between the trough (302) and mounting hole (301) may be equal to or greater than radius of the mounting hole (301).
[21] In accordance with the embodiments of the present invention, each trough (302) is formed at a central position on the surface of the flange (300). The surface of the flange (300) is the outer face of the flange (300). Further, the troughs (302) are provided such that crests are formed on non-contacting surface (300B) of the flange (300).
[22] In accordance with the present invention, the troughs (302) provide an extra space for a sealing element. The sealing element goes inside the troughs (302) while fixing the cover (100) with the body (101) of the differential housing (1000). The sealing element is configured to facilitate an increase in uniformity of sealing therebetween the body (101) and the cover (100) of the differential housing (1000) thereby preventing the oil leakage therefrom the differential housing (1000).
In accordance with the present invention, the sealing element is a room temperature vulcanizing (RTV) oxime silicone adhesive.
[23] In accordance with the embodiments of the present invention, the depth (D) of the trough (302) depends on thickness of the flange (300) and width (W) of the trough (302) depends on width of the flange (300). According to the present invention, a preferable ratio of a depth (D) to a width (W) of the trough (302) is in the range of 0.5:11 to 2:15. In an exemplary embodiment, a more preferable ratio of a depth (D) to a width (W) of the trough (302) is 1:13.
[24] In another aspect, the present invention also relates to a flange (300) for a cover which imparts stiffness. The flange (300) comprises a plurality of mounting holes (301) and a plurality of troughs (302) provided on a contacting surface (300A) of the flange (300) forming crests on non-contacting surface (300B) of the flange (300) correspondingly for increasing the stiffness of the flange (300).
[25] In accordance with the embodiments of the present invention, the trough (302) is provided between the mounting holes (301) based on the stress analysis (contour plot numerical simulation analysis). In another embodiment, the plurality of troughs (302) is provided on the bottom side of the flange (300).
[26] The cover (100) of the present invention increases uniformity of sealing and reduces the contact opening between the body (101) and the cover (100) of the differential housing (1000). Further, the troughs (302) prevent torsion, twisting and warpage of the cover (100). Furthermore, the flange (300) of the present invention has increased stiffness due to presence of the plurality of troughs (302) thereon the flange (300).
[27] Example:
A contour plot numerical simulation analysis in computer-aided engineering (CAE) was performed for the contact opening of a cover of the prior art and the cover of the present invention. The simulation analysis is shown in figure 6 (prior art) and figures 7-8 (present invention). The simulation analysis was performed to minimize the contact opening between the body (101) and the cover (100) of the differential housing (1000).
From figures 6 to 8, it is evident that the cover (100) which is devoid of troughs (302) (prior art) has the contact openings on the bottom left-hand side of 50 microns and bottom right-hand side of 43 microns. However, in accordance with the cover (100) of the present invention, when the troughs (302) are provided on a contacting surface (300A) of the flange (300) that form crests on non-contacting surface (300B) of the flange (300), the contact openings on the bottom left-hand side are reduced to 26 microns (shown in figure 7 (b) i.e. iteration 1), 2 microns (shown in figure 8 (b) i.e. iteration 2) and the contact openings on bottom right-hand side are reduced to 7 microns (shown in figure 7 (b) i.e. iteration 1), and 8 microns (shown in figure 7 (b) i.e. iteration 1), in comparison with the cover (100) of the prior art (figure 6 a-b). Accordingly, the reduction in the contact opening in the cover (100) of the present invention implies that potential of the oil leakage between the body (101) and the cover (100) of the differential housing (1000) is very less. Further, the troughs (302) provided on the surface of the flange (300) prevent deflection between the cover (100) and the body (101) of the differential housing (1000).
[28] The terms and words used in the following description are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of the system is for the purpose of understanding and nowhere limit the invention. The abovementioned parts nowhere limit the invention and are provided for understanding of the invention.
[29] Although there has been shown and described the preferred embodiment of the present invention, it will be readily apparent to those skilled in the art that modifications may be made thereto which do not exceed the scope of the appended claims. Therefore, the scope of the invention is only to be limited by the following claims.
LIST OF REFERENCE NUMERALS
[30]
1000 Differential housing
100 Cover
101 Body
200 Recess
300 Flange
300A Contacting surface of the flange
300B Non-contacting surface of the flange
301 Mounting holes
302A Troughs
302B Crests

, Claims:
1. A cover (100) for differential housing (1000) of a vehicle for accommodating an axle gear, said cover (100) comprising:
a recess (200) for accommodating a portion of the axle gear of a differential gear system;
a flange (300) around the periphery of said recess (200), said flange (300) having a plurality of mounting holes (301); and
a plurality of troughs (302A) provided on a contacting surface (300A) of the flange (300) forming a plurality of crests (302B) on non-contacting surface (300B) of the flange (300) correspondingly for increasing the stiffness of the cover (100) and obtaining the uniformity of sealing by reducing the contact opening between a body (101) and the cover (100) of the differential housing (1000).

2. The cover (100) as claimed in claim 1, wherein said plurality of troughs (302A) are provided away from the proximity of the said plurality of mounting holes (301).

3. The cover (100) as claimed in claim 1, wherein a minimum distance between the trough (302) and mounting hole (301) is equal to or greater than radius of the mounting hole (301)

4. The cover (100) as claimed in claim 1, wherein each trough (302A) is formed at a central position on the surface of said flange (300).

5. The cover (100) as claimed in claim 1, wherein depth and width of the trough (302A) are based on thickness and width of the flange (300).
6. The cover (100) as claimed in claim 1 or 4, wherein a ratio of a depth (D) to a width (W) of said trough (302A) is in the range of 0.5:11 to 2:15.

7. The cover (100) as claimed in claim 1, wherein said plurality of troughs (302A) is provided between the mounting holes (301).

8. The cover (100) as claimed in claim 1, said plurality of troughs (302A) are provided on the bottom side of said flange (300).

9. A flange (300) for a cover (100) comprising:
a plurality of mounting holes (301); and
a plurality of troughs (302A) provided on contacting surface (300A) of said flange (300) forming crests (302B) on non-contacting surface (300B) of the flange (300) correspondingly for increasing the stiffness of said flange (300).