Assembly Workbench

QUICK RETURN MECHANISM & CV JOINT

OBJECTIVE:

In part workbench or generative workbench, create rapid return mechanism and CV joint parts and assemble them according to all guidelines.

CATIA V5 was used as the software.

INTRODUCTION:

a) MECHANISM FOR QUICK RETURN:

A quick return mechanism is a device that generates a reciprocating motion in which the return stroke takes less time than the forward stroke. It uses a system of links with three turning pairs and a sliding pair to be driven by a circular motion source (usually a motor of some sort).

There are three different types of quick return mechanisms available.

• Hydraulic power
• Mechanism with a crank and a slotted link
• Mechanism of Whitworth

A quick return mechanism is a mechanism that produces a reciprocal effect so that the system takes less time in the return stroke while comparing with forwarding stroke. In the quick-return mechanism, a circular movement like the crank and lever mechanism is converted into reciprocal movement but the return time is different from the forward moment. In several applications, this process is used. Some of them are shaper, slotter, screw-press, mechanical drive, etc. The time required for cutting is reduced with the assistance of a quick return mechanism.

b) CV JOINT:

Constant-velocity joints (also known as homokinetic or CV joints) allow a drive shaft to transmit power through a variable angle, at constant rotational speed, without an appreciable increase in friction or play. They are mainly used in front-wheel drive vehicles. Modern rear-wheel-drive cars with independent rear suspension typically use CV joints at the ends of the rear axle half shafts and increasingly use them on the drive shaft.

All front-wheel-drive cars have Constant Velocity joints or CV joints on both ends of the drive shafts (half shafts). Inner CV joints connect the drive shafts to the transmission, while the outer CV joints connect the drive shafts to the wheels. Many rear-wheel drives and four-wheel drive cars, as well as trucks, also have CV joints.

The CV joints are needed to transfer the torque from the transmission to the drive wheels at a constant speed while accommodating the up-and-down motion of the suspension. In front-wheel-drive cars, CV joints deliver the torque to the front wheels during turns. There are two most commonly used types of CV joints: a ball-type and a tripod-type. In front-wheel-drive cars, ball-type CV joints are used on the outer side of the drive shafts (outer CV joints), while the tripod-type CV joints are mostly used on the inner side (inner CV joints).

PROCEDURE:

1)First create all the parts of QUICK RETURN MECHANISM as well as of CV JOINT.

2)Create all the parts separately in the part workbench or generative workbench.

3)First create the sketch of the part in the sketching workbench and make sure that the sketch is Iso constraint.

4)Then pad that sketch using pad feature in the part workbench or extrude and trim accordingly in generative workbench.

5)Use Boolean operations and add or remove to obtain the required output.

6)While creating the parts in the generative workbench make sure that you close the surface of the part you created.

7)Create all the parts and save the CAT. Part of all the parts that you have created separately.

8)Then go to the assembly workbench and open all the parts that you created using the “open existing component” feature.

9)Then assemble them accordingly using the constraint toolbox and move the parts in various directions as you need using the move toolbar.

COMMANDS USED:

• 1.PAD
• 2.UNION TRIM
• 3.EXTRUDE
• 4.EXTRAPOLATE
• 5.TRIM
• 6.SPLIT
• 7.CLOSE SURFACE
• 8.COINCIDE
• 9.CONSTRAINT
• 10.MOVE

CONCLUSION:

The quick return mechanism and cv joint assembly has been done following all the guidelines.