DESC:FIELD OF INVENTION

The present invention relates to a mechanism for the assembly of automotive components. In particular, the present invention relates to a mechanism for stretching Gear Carrier (differential) housing. More particularly, the present invention relates to assembling automotive components like differential sub-assembly into the Banjo Axle Gear Carrier (differential) housing.

BACKGROUND OF THE INVENTION

An automotive vehicle with dependent rear suspension uses a dead axle which only supports the vehicle weight or uses a live axle which is also having a shaft and gear mechanism for driving its wheels. The latter provides driving traction by using an axle-hub mounted on axle casing and supported by ball/roller bearings.

Therefore, two main components fitted into the rear-wheel driven vehicle axle are the final drive and differential. Nowadays, the axle casing could be a Banjo type or Carrier type casing, which actually determines the method for removing the final drive.

The tubular axle section of the Banjo type casing/housing is made of steel pressings welded together and appropriately reinforced to bear bending loads acting thereon. The differential sub-assembly in Banjo type axle housing in automotive vehicles is a critical component for the rear-axle performance.

The final drive assembly is mounted in a detachable housing of malleable cast iron and fastened on the axle casing by means of several bolts. The axle shafts are inserted from the wheel end of the axle casing.

Some banjo axles are fitted with a domed plate on the rear face of the axle casing. By removing this plate, the final drive gears can be accessed and if the axle shaft is secured to the differential, it facilitates in unlocking the axle shaft from the sun gear (side gear).
The assembly process of Banjo type axle casing is quite difficult due to strain prevailing therein, causing more fatigue and requiring more time to assemble. The end bearings of the differential sub-assembly always require a preloading for proper functioning of the rear-axle.

For this purpose, the bearing to bearing dimensions are configured slightly larger than the housing dimensions. Thus, fitment of this differential is carried out by hammering (mallet) the sub-assembly into the housing (Figure 1).

Some OEMs also provide threading arrangements while designing the part itself (which is a costly affair) for preloading of bearings (Figure 2).

DISADVANTAGES WITH THE PRIOR ART

However, the problem with the conventional method using hammering (by a mallet) on the sub-assembly into the housing is that it is quite difficult due to strain prevailing therein, which causes more fatigue and requires substantially more time to assemble.

Therefore, there is need for stretching mechanism to expand Banjo housing for insertion of differential sub-assembly therein.

The simple expansion would have required tremendous force, but a hydraulic mechanism using leverage principle and cantilever configuration along with material elasticity is developed according to the novel concept of the present invention for achieving higher expansion with substantially lesser force.

OBJECTS OF THE INVENTION

Some of the objects of the present invention - satisfied by at least one embodiment of the present invention - are as follows:

An object of the present invention is to provide a cost-effective Banjo type axle housing for differential assembly.
Another object of the present invention is to provide a cost-effective Banjo type axle housing for differential assembly which reduces the cycle time and increases the production capacity thereof.

Still another object of the present invention is to provide a Banjo type axle housing for differential assembly which is configured ergonomically to reduce the operator’s fatigue and thereby increases operator’s morale.

Yet another object of the present invention is to provide a Banjo type axle housing for differential assembly, which introduces a zero-defect process.

A further object of the present invention is to provide a Banjo type axle housing for differential assembly, which eliminates operator’s injury during the erstwhile mallet tapping thereof.

A still further object of the present invention is to provide a Banjo type axle housing for differential assembly, which reduces noise generation during the assembly process thereof.

A yet further object of the present invention is to provide a Banjo type axle housing for differential assembly, which achieves higher expansion with substantially lesser force.

These and other objects and advantages of the present invention will become more apparent from the following description, when read with the accompanying figures of drawing, which are however not intended to limit the scope of the present invention in any way.

DESCRIPTION OF THE INVENTION

Accordingly, the Banjo Gear carrier housing is stretched to accommodate the differential sub-assembly by using the principle of leverage and cantilever and the property of elasticity of the material thereof.
The stretching mechanism of the aforesaid Banjo Gear carrier (Differential) housing using the leverage and cantilevered configuration uses less force and achieves more deflection due to the elasticity of the material Spheroidal Graphite Iron used therein.

The Banjo housing is located in fixture, both RH and LH levers are engaged and then the cycle on two hand safety switches are operated for applying the suitable force, preferably a hydraulic force for expanding Banjo housing before assembling the differential sub-assembly therein.

After assembly, the hydraulic pressure is released, and bearings caps fitted on Banjo housing. Subsequently, Banjo differential assembly proceeds to next stage for further operation thereon. Levers are used on the cantilever type portion of Banjo type gear carrier (differential) housing.

Although, it is common to use direct pulling configuration, however here, the mechanism uses lesser force or pressure and offers a higher deflection, which otherwise would have required higher force.

SUMMARY OF THE INVENTION

In accordance with the present invention, there is provided a stretching mechanism for vehicle axle Banjo housing for assembly of the differential sub-assembly therein, wherein the mechanism comprises:

• a base for supporting the mechanism on the floor;

• a fixture for mounting and locating Banjo housing;

• a plurality of levers with a respective linkage on a cantilever portion on either side of the fixture;

• a displacement device to provide movement and stretching force to the levers equipped with a respective linkage; and

• a plurality of switches for operating the displacement device;

wherein the Banjo housing is mounted and located on the fixture and stretched outwards by a predetermined amount to facilitate insertion of the differential sub-assembly within the Banjo housing.

Typically, the levers are configured as a left-hand side lever and a right-hand side lever disposed on a respective cantilever portion on either side of the Banjo housing.

Typically, the bearing face to bearing face dimension of the differential sub-assembly bearing face is slightly greater than the bearing face to bearing face dimension of the Banjo housing to ensure a secured assembly.

Typically, the displacement device comprises a hydraulic power pack with hydraulic cylinder to operate the levers to apply stretching force on the Banjo housing.

Typically, the cantilever portions and the Banjo housing supported thereon are stretched outwards to expand by means of the hydraulic cylinder by a distance predetermined depending on the bearing face to bearing face dimension of the differential assembly to be assembled within the Banjo housing.

Typically, the stretched-out Banjo housing is fitted with differential fitted with bearings at both side of the differential sub assembly.

Typically, the differential sub-assembly fitted with bearings is inserted between the stretched bearing faces of the Banjo housing and this stretching force applied by the hydraulic cylinder is released for a secure assembly of the differential sub-assembly within the Banjo housing.

Typically, the cantilever portions are retracted to the initial position thereof on releasing the stretching force to allow the Banjo housing to regain its original shape and size after assembly of differential assembly therein.

Typically, the switches comprise a pair of cyclic operating switches for switching on/off the hydraulic power pack and a pair of manually operated safety switches as well as a switch for emergency switch-off of the hydraulic power pack.

Typically, the Banjo housing is stretched within elastic limit of the material constituting the Banjo housing.

In accordance with the present invention, there is also provided a method for the assembly of a differential sub-assembly within a Banjo housing for automotive vehicles, the method comprising the steps of:

a) mounting and locating the Banjo housing on the fixture;

b) engaging one of the levers on the cantilever portions on either side of the Banjo housing;

c) switching on the hydraulic power pack to actuate hydraulic cylinder to apply stretching force on the levers with linkages to stretch the Banjo housing ends;

d) stretching the Banjo housing by an amount predetermined depending on the face to face dimension of the bearings to be fitted in the Banjo housing for the assembly of the differential sub-assembly;

e) placing the differential sub-assembly fitted with bearings within the Banjo housing;

f) releasing stretching force applied by the hydraulic cylinder;

g) placing and fixing the bearings caps on the retracted Banjo housing; and

h) unloading the entire assembly from the fixture and to be sent to next stage.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The present invention will be briefly described with reference to the accompanying drawings.

Figure 1 shows the conventional arrangement of fitting the sub-assembly into Banjo housing for differential or gear carrier by using a mallet.

Figure 2 shows another conventional arrangement of fitting the sub-assembly into Banjo housing for differential or gear carrier by using threads.

Figure 3a shows the stretching mechanism configured in accordance with the present invention for the assembly of Banjo type differential housing.

Figure 3b shows an enlarged side view of Banjo type differential housing depicted in Figure 3a.

Figure 3c shows a side view of the fixture located and mounted with the Banjo type differential housing depicted in Figure 3a.

DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS

In the following, the stretching mechanism configured in accordance with the present invention for assembling Banjo type gear carrier (differential) housing will be described in more details with reference to the accompanying drawings without limiting the scope and ambit of present invention in any way.

Figure 1 shows the conventional arrangement of fitting the sub-assembly into Banjo housing BH for differential D or gear carrier by manually hammering by using a mallet M to reduce/increase the dimension Y with respect to dimension X in the assembly for preloading the bearings. Here, the dimension Y is substantially greater than dimension X.

Figure 2 shows another conventional arrangement of fitting the sub-assembly into Banjo housing BH for differential D or gear carrier by using threads Th to reduce/increase dimension Y with respect to dimension X in the assembly for preloading the bearings. Here also, the dimension Y is substantially greater than dimension X.

Figure 3a shows the stretching mechanism configured in accordance with the present invention for the assembly of Banjo type gear carrier (Differential) housing. It includes a left-hand side lever (LHL) and a right-hand side lever (RHL) as well as cycle on switches (COS) fitted on a fixture for mounting and locating the Banjo housing BH on top surface thereof. The mechanism is powered by a laterally connected hydraulic power pack (HPP) having a hydraulic cylinder to transfer the motion thereof to the cantilever portion CP of Banjo housing BH. The cantilever portions are retracted back after the differential assembly is inserted within the stretched-out Banjo housing.

Figure 3b shows an enlarged side view of Banjo type gear carrier differential housing BH depicted in Figure 3a. It shows the deflection due to stretching by means of stretching forces F, which expand Banjo housing BH before assembling the differential sub-assembly therein.

Figure 3c shows a side view of the fixture located and mounted with the Banjo type differential housing depicted in Figure 3a. All constructional features of the Banjo housing stretching mechanism are clearly visible here. It shows the fixture (FX) mounting the Banjo type gear carrier (Differential) housing (BH). The left-hand side lever (LHL) and right-hand side lever (RHL) are disposed on the cantilever portion (CP). On operating the Cycle-On-Switches (COS) fitted on the fixture (FX) the hydraulic cylinder (HC) powered by hydraulic power pack (HPP) (not shown). This hydraulic cylinder (HC) transfers the motion thereof to the cantilever portion CP of Banjo housing BH to produce stretching force (SF) on either side of the Banjo housing (BH) via left-hand side lever (LHL) and right-hand side lever (RHL) with the linkages thereof in order to expand Banjo housing (BH) by a predetermined amount for facilitating the assembly of differential sub-assembly therein.

CONSTRUCTIONAL FEATURES OF THE INVENTION

The Banjo-housing stretching mechanism includes the following elements:

Fixture (FX) for locating and mounting Banjo Housing BH.
Left-hand and Right-hand side levers (LHL, RHL) along with linkages for obtaining motion from the hydraulic cylinder of the hydraulic power pack HPP and to transfer this movement/force to the cantilever portion CP of the Banjo housing BH. These levers are pivoted and can be engaged and disengaged from the Banjo housing.

Hydraulic Power Pack (HPP) to deliver required hydraulic pressure in the hydraulic circuit and to maintain a constant pressure when required for stretching the Banjo type axle housing or simply referred to as Banjo housing BH and to release this pressure when differential sub- differential sub-assembly is completed.

Hydraulic Cylinder (HC) operated by the hydraulic power pack HPP to provide movement and hydraulic force to the linkages and LHL, RHL.

Cycle Operating Switches (COS) for ON/OFF of cycle along with two hand safety switches and Emergency off switch.

Common Mechanism Base (CMB) to support entire mechanism on floor and withstand all forces during operation.

WORKING PRINCIPLE OF THE INVENTION

Banjo Gear carrier housing BH is mounted in the fixture (FX) and two levers (RHL, LHL) are engaged on the cantilever type portion on the Banjo gear carrier. With the help of a hydraulic cylinder of the hydraulic power Pack (HPP), these levers RHL, LHL are pulled away from each other (see Fig. 3b) and thereby the Banjo gear carrier housing is stretched by about 0.200 mm (preferably within elastic limit of its material) to increase face to face dimension thereof.

Accordingly, it easily accommodates the differential assembly (having a higher Bearing face to Bearing face dimension than Banjo gear carrier by about 0.175 mm.

After inserting the differential assembly into the Banjo housing (BH), the hydraulic cylinder is retracted, and the cantilever portion of the Banjo gear carrier retracts to its initial position.

Banjo housing BH is located in the fixture, both levers (RHL, LHL) are engaged and then two cycle-on safety switches are manually operated to apply a hydraulic force for expanding Banjo housing BH in order to finally assemble the differential sub-assembly therein.

Thereafter, the aforesaid hydraulic pressure is released, and bearings are fitted on Banjo housing BH. After completing the assembly, the banjo differential assembly is taken to next stage for further processing of the rear-axle assembly.

TECHNICAL ADVANTAGES AND ECONOMIC SIGNIFICANCE

The system proposed in accordance with the present invention has the following technical and economic advantages:

• Ergonomically converts the assembly stage from yellow to Green.

• Eliminates associated fatigue, thereby increasing operator’s morale.

• Safe operation for associate, since mallet hammer tapping is eliminated.

• Reduces noise level from 80 to 72 db.

• Reduces the cycle time of the differential assembly bottleneck stage.

• Increases the production capacity from 192 to 264 per, thereby substantial addition of about 21600 per year.
• Zero defects achieved at this stage wrt the old process (5 defects/shift).

• Capital saving of Rs. 3 Lakh on account of completely new machine.

• Meets additional demands of new generation automobiles.

• Supports additional sales revenue generation and facilitates zero loss due to improved Banjo Gear carrier assembly.
It is to be understood that the present invention is not limited in its application to the details of the construction and to the arrangements of the components as mentioned in the above description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, the terminologies used herein are for the purpose of description and should not be regarded as limiting.

The foregoing description of the specific embodiments will 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. 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 distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.

The description provided herein is purely by way of example and illustration. The various features and advantageous details are explained with reference to this non-limiting embodiment in the above description in accordance with the present invention.

The descriptions of well-known components and manufacturing and processing techniques are consciously omitted in this specification, so as not to unnecessarily obscure the specification. 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, the skilled person will recognize that the embodiments herein can be practiced with modification within the spirit and scope of embodiments described herein.

The skilled person can easily make innumerable changes, variations, modifications, alterations and/or integrations in terms of materials and method used to configure, manufacture and assemble various constituents, components, subassemblies, assemblies and in terms of the size, shapes, orientations and interrelationships without departing from the scope and spirit of the present invention.

The numerical values given of various physical parameters, dimensions and quantities are only approximate values and it is envisaged that the values higher or lower than the numerical value assigned to the physical parameters, dimensions and quantities fall within the scope of the disclosure unless there is a statement in the specification to the contrary.

Throughout this specification, the word “comprise”, or variations such as “comprises” or “comprising”, shall be understood to implies including a described element, integer or method step, or group of elements, integers or method steps, however, does not imply excluding any other element, integer or step, or group of elements, integers or method steps.

The use of the expression “a”, “at least” or “at least one” shall imply using one or more elements or ingredients or quantities, as used in the embodiment of the disclosure in order to achieve one or more of the intended objects or results of the present invention. ,CLAIMS:We claim:

1. Stretching mechanism for vehicle axle Banjo housing for assembly of the differential sub-assembly therein, wherein said mechanism comprises:

• a base for supporting said mechanism on the floor;

• a fixture for mounting and locating Banjo housing;

• a plurality of levers with a respective linkage on a cantilever portion on either side of said fixture;

• a displacement device to provide movement and stretching force to said levers equipped with a respective linkage; and

• a plurality of switches for operating said displacement device;

wherein said Banjo housing is mounted and located on said fixture and stretched outwards by a predetermined amount to facilitate insertion of said differential sub-assembly within said Banjo housing.

2. Stretching mechanism as claimed in claim 1, wherein said levers are configured as a left-hand side lever and a right-hand side lever disposed on a respective cantilever portion on either side of said Banjo housing.

3. Stretching mechanism as claimed in claim 2, wherein said bearing face to bearing face dimension of the differential sub-assembly bearing face is slightly greater than the bearing face to bearing face dimension of said Banjo housing to ensure a secured assembly.

4. Stretching mechanism as claimed in claim 1, wherein said displacement device comprises a hydraulic power pack with hydraulic cylinder to operate said levers to apply stretching force on said Banjo housing.

5. Stretching mechanism as claimed in claim 4, wherein said cantilever portions and said Banjo housing supported thereon are stretched outwards to expand by means of the hydraulic cylinder by a distance predetermined depending on the bearing face to bearing face dimension of the differential assembly to be assembled within said Banjo housing.

6. Stretching mechanism as claimed in claim 5, wherein said stretched-out Banjo housing is fitted with differential fitted with bearings at both side of the differential sub assembly.

7. Stretching mechanism as claimed in claim 6, wherein said differential sub-assembly fitted with bearings is inserted between the stretched bearing faces of the Banjo housing and this stretching force applied by the hydraulic cylinder is released for a secure assembly of the differential sub-assembly within the Banjo housing.

8. Stretching mechanism as claimed in claim 5, wherein said cantilever portions are retracted to the initial position thereof on releasing said stretching force to allow said Banjo housing to regain its original shape and size after assembly of differential assembly therein.

9. Stretching mechanism as claimed in claim 1, wherein said switches comprise a pair of cyclic operating switches for switching on/off said hydraulic power pack and a pair of manually operated safety switches as well as a switch for emergency switch-off of said hydraulic power pack.

10. Stretching mechanism as claimed in claim 5, wherein said Banjo housing is stretched within elastic limit of the material constituting said Banjo housing.

11. A method for the assembly of a differential sub-assembly within a Banjo housing for automotive vehicles, said method comprising the steps of:

(i) mounting and locating said Banjo housing on said fixture;

(ii) engaging one of said levers on said cantilever portions on either side of said Banjo housing;

(iii) switching on said hydraulic power pack to actuate hydraulic cylinder to apply stretching force on said levers with linkages to stretch said Banjo housing ends;

(iv) stretching said Banjo housing by an amount predetermined depending on the face to face dimension of the bearings to be fitted in said Banjo housing for the assembly of said differential sub-assembly;

(v) placing said differential sub-assembly fitted with bearings within said Banjo housing;

(vi) releasing stretching force applied by said hydraulic cylinder;

(vii) placing and fixing said bearing caps on said retracted Banjo housing; and

(viii) unloading the entire assembly from said fixture to be sent to next stage.

Digitally Signed.

Dated: this day of 31st January 2018. (SANJAY KESHARWANI)
APPLICANT’S PATENT AGENT