Transmission Sealing System

Field of the Invention:

The present invention relates to a "Transmission Sealing System" and more particularly for an automobile.

Background of the Invention:

Constant velocity universal joints are commonly used for connecting a driving member with a driven member whose distance from the driving member varies over a wide range.

Generally a propeller shaft connects an engine output to either wheels of a vehicle through universal joints. The propeller shaft at both ends is slidably connected with muff cups using a pin and slider block assembly. The muff cups are connected with the driving member and driven member respectively such that any change within specified limits in the distance between the driving member and driven member can be accommodated by the sliding connection between the propeller shaft and muff cups. Lubricating grease is applied over the sliding surfaces of the slider block assembly and muff cups to reduce friction and subsequent wear and tear. Bellows or drive shaft boots are used to cover the universal joints to prevent contamination of the lubricating grease due to ingress of water and other impurities from the external environment. The bellows seal the universal joints from the external environment and thereby avoid water and dust entry.

A clamp is conventionally used for the bellows to achieve the desired sealing function for each joint. Regardless of the type of sliding connection and type of driving member and driven member, bellows with clamps are used to seal the universal joints without affecting the movement of the shaft along the three different axes. Problems associated with providing a clamp to bellow are non uniform pressure distribution, assembly time is high, and cost is high.

Hence the objective of the present invention is to overcome the above problems associated with the prior arts.

Summary of the Invention:

The present invention has been devised in view of the above difficulties and it is therefore an object of the present invention is to isolate the universal joint from the external environment using bellows and achieving the same without clamps.

Another object of the present invention is to provide bellows with at least one groove or at least one projection for mating with a corresponding groove or projection of a fixed member.

Another object of the present invention is to ensure the inner diameter of the bellow which snaps on the mating part is less than the mating part outer diameter.

Yet another object of the present invention is to use the elastic property of bellow with groove / projection on bellow and mating part to hold the bellow tightly and seals the mating surfaces without clamp.

Further object of the present invention is to arrest the undesirable axial movement of the bellow which is restricted by the groove and projection in bellow and mating part.

Further object of the present invention is to reduce the part counts.

Further object of the present invention is to make the system cost effective.

Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

Brief Description of the Drawings:

The present invention will become more fully understood from the detailed description given herein below and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein

Figure 1 illustrates a three wheeler.

Figure 2 shows a constant speed universal joint.

Figure 3 shows cut section of the universal joint according to one embodiment of the present invention.

Figure 4 shows cut section of the universal joint according to another embodiment of the present invention.

Detailed Description of the Drawings:

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

Referring to Fig 1, a three wheeler comprises a chassis (10) made up of hollow rectangular cross members with which various parts are connected. Two long cross members, long cross member LH (11) and long cross member RH (12) are located on the two sides of the vehicle axis along the direction of travel. Two engine mounting cradles, engine mounting cradle front and engine mounting cradle rear (14) are connected with the two long cross members for mounting an internal combustion engine. There is a cross tube (15) that is welded to the two long cross members at right angles for supporting rear trailing arms (LH and RH). A central long member is connected with the cross tube and along with the two long cross members, it supports a floor board (17). A rear seat frame is connected with the two long cross members for mounting a passenger seat. A rear cabin upper cross member (19) is connected with the two long members for supporting a rear cabin. There is a front cowl (20) connected with the floor board. The front cowl supports a windshield. There is a B—pillar connected with the long cross members for supporting a partition wall (22). The partition wall separates the passenger seating area from the driver seating area. A soft top connecting tube (23) is fitted to the B-pillar for connecting a soft top cover between the rear cabin and the windshield. A driver seat frame is located in front of the partition wall for mounting a driver seat. Additional connecting tubes are fitted with the cabin for supporting the soft top cover. Two rear wheels are connected to each trailing arm LH and RH. Each trailing arm has a pivot point and a suspension support with the corresponding long cross member. A front wheel is connected with a front trailing arm which in turn has a pivot joint with a steering column.

There is a front suspension support between the trailing arm and the steering column. A handle bar is connected with the steering column for changing the direction of travel of the vehicle. There is a dashboard connected with the front cowl and comprising the various switches and indicators for helping the driver in starting and driving the vehicle in traffic conditions.

According to the present system and referring to figure 2, transmission sealing system having a constant speed universal joint (201) comprises a propeller shaft (202) slidably connected with a muff cup (203) and is sealed from the external environment by a flexible bellow (204). A slider block assembly (301) (shown in figure 3) is used to slidably connect the propeller shaft (202) with a muff cup.

The said propeller shaft (202) which is slidably connected to the said muff cup (203) forms a constant speed universal joint that is sealed from the external environment using a bellow. There is no separate clamp is provided to seal the bellow with the muff cup.

In one of the embodiment of the invention the said muff cup end flange (302) is provided with circumferential grooves for mating with corresponding circumferential projections in bellow (303). The movement of the bellow along the axial direction of the propeller shaft thereby is restricted by the interlocking between the said muff cup grooves (302) and said bellow projections (303). The inner diameter of bellow is made lesser than the outer diameter of muff cup such that the said bellow seals the sliding connection between slider block and muff cup

In another embodiment of the invention and referring to figure 4, the muff cup has circumferential projections (401) in the end flange and bellow has circumferential grooves (402) for sealing the universal joint from the external environment to prevent dust and water entry. The inner diameter of the bellow is made smaller than the outer diameter of the muff cup to achieve the desired sealing of the universal joint.

Regardless of the type of sliding joint between the shaft and driving member / driven member, the clamp less bellow assembly can achieve the sealing of the universal joint from the external environment. By eliminating the requirement of a clamp for each universal joint, cost reduction and part count reduction is achieved. Ease of service is also ensured as the service personnel need not remove any clamp for adding lubricating grease to the sliding surfaces.

The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the claims.

We Claim:

1. A transmission sealing system for constant velocity universal joints comprises

a propeller shaft;

a muff cup, slidably connecting the propeller shaft; and

a bellow to cover the muff cup

wherein the bellow is provided with at least one groove to snugly fit with the

corresponding projection on the muff cup.

2. A transmission sealing system for constant velocity universal joints comprises

a propeller shaft;

a muff cup, slidably connecting the propeller shaft;and

a bellow to cover the muff cup

wherein the bellow is provided with at least one projection to snugly fit with the
corresponding groove on the muff cup.

3. A transmission sealing system for constant velocity universal joints as claimed in claim 1 and claim 2, wherein the said bellow inner diameter is less than the outer
diameter of the muff cup.