AIM :
To create part models and assemble the components using the 2D drawings which were provided.
OBJECTIVE :
- The main aim of this report is to explain the procedure involved in design and assembly of
- CV joint and Quick return mechanism with the help of given 2D drawing sheetTo create the various part models from the 2D drawings.
- To asseble the part models into a single component.To create the 2D drawings of the components which were created.
- To create quick return mechanism and CV joint parts in part work bench or generative work bench and assemble them following all the guidelines.
SOFTWARE USED:
CATIA V5.
INTRODUCTION:
a) QUICK RETURN MECHANISM:
- A quick return mechanism is an apparatus to produce a reciprocating motion in which the time taken for travel in return stroke is less than in the forward stroke. It is driven by a circular motion source (typically a motor of some sort) and uses a system of links with three turning pairs and a sliding pair.
There are three types of quick return mechanism
- Hydraulic drive
- Crank and slotted link mechanism
- Whitworth mechanism
- A quick return mechanism is a mechanism which produces a reciprocal effect so that the system takes less time in the return stroke while comparing with forward 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 halfshafts 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 drive 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 work bench or generative work bench.
- 3)First create the sketch of the part in sketching work bench and make sure that the sketch is Iso constraint.
- 4)Then pad that sketch using pad feature in part work bench or extrude and trim accordingly in generative work bench.
- 5)Use Boolean operations and add or remove to obtain the required output.
- 6)While creating the parts in generative work bench make sure that you close surface 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 work bench and open the all the parts that you created using “open existing component” feature.
- 9)Then assemble them accordingly using the constraint tool box and move the parts in various directions as you need using move tool bar.
PARTS OF QUICK RETURN MECHANISM:
PARTS OF CV JOINT:
COMMANDS USED:
1.PAD
2.UNION TRIM
3.EXTRUDE
4.EXTRAPOLATE
5.TRIM
6.SPLIT
7.CLOSE SURFACE
8.COINCIDE
9.CONSTRAINT
10.MOVE
In this challenge, I have to design part models and assemble the parts from the 2D sketches and dimensions provided to me.
QUICK RETURN MECHANISM
- A quick return mechanism is an apparatus to produce a reciprocating motion in which the time taken for travel in return stroke is less than in the forward stroke. It is driven by a circular motion source (typically a motor of some sort) and uses a system of links with three turning pairs and a sliding pair. A quick-return mechanism is a subclass of a slider-crank linkage, with an offset crank.Quick return is a common feature of tools in which the action is performed in only one direction of the stroke, such as shapers and powered saws because it allows less time to be spent on returning the tool to its initial position.
now I will create each part shown in the above quick return mechanism. I'll use the Boolean method features to create all the parts.
1. quick return mechanism frame
1.Holding of frame
2. Slider
3. Crank
4. Crank holder
Assembly of made parts
various views
After finishing the first assembly i will now work on the next assembly which is the CV joint
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.
now I will create each part shown in the above CV - joint. I'll use the Boolean method features to create all the parts.
1. Conjunction part or 'I' type component
2. circular converging part
3. Vertical movement part or type 'C' part.
Assembly of made parts
Various views
After working with the assembly workbench in CATIA. I got to know various relations and constraints that would be joined together to make a full working assembly.
And I got to know how to work with parts and their assembly and also the different tools used for assembly.
DESIGN AND ASSEMBLY OF CV JOINT AND QUICK RETURN MECHANISM
Description:
CV joint:
Constant-velocity joints (also known as homokinetic or CV joints) are mechanical joints which 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 halfshafts and increasingly use them on the drive shaft.
CV joint parts:
For the given cv joint there are 3 parts. They are,
- Vertical holding cups
- Centre shafts
- Horizontal C cups.
The input given to create CV joint is shown in the above picture.
Part creation for the CV joint:
The following steps are involved in part creation for the CV joint,
- The positioned sketches are created under the construction elements with iso-constrained geometry in the sketcher workbench with reference to the given sheets.
- These sketches are created in the appropriate planes to create solid parts.
- With help of those sketches solid parts are created using the pad command in the part work bench along the required direction.
- Then the parts are added and removed with help of Boolean operations according to the requirements.
Assembly:
The following steps are involved in the assembly of parts created before to form an CV joint.
- The assembly process is carried out in the assembly work bench and the assembly file has .CATProduct as its extension.
- The assembly of CV joint starts with reference to the reference elements created in the part level.
- In part level the reference points, axis and planes are published to ease of access in the assembly work bench. Those publications are child features, if the parent features are modified in the part level its publications also gets modified.
- Previously created parts are opened in the assembly work bench as child features of product, then a new part is created to serve as an assembly reference.
- This assembly reference is fixed to arrest its all degrees of freedom to hold the parts together.
- After the fixation, the parts are assembled with giving the coincident and offset relations to the appropriate planes, axis and points.
Assembled CV joint is shown in the picture.
Quick return mechanism:
A quick return mechanism is an apparatus to produce a reciprocating motion in which the time taken for travel in return stroke is less than in the forward stroke. It is driven by a circular motion source (typically a motor of some sort) and uses a system of links with three turning pairs and a sliding pair.
Quick return is a common feature of tools in which the action is performed in only one direction of the stroke, such as shapers and powered saws, because it allows less time to be spent on returning the tool to its initial position.
Quick return mechanism parts:
For the given quick return mechanism there are 5 parts. They are,
- Slotted link
- Pivot block
- Sliding block
- Crank
The input given to create Quick return mechanism is shown in the above picture.
QUICK RETURN MECHANISM
ASSEMBLY
FEATURE TREE
DRAWING
DRAWING 1
PART 2
DRAWING 2
PART 3
DRWAING 3
PART 4
DRAWING 4
PART 5
DRAWING 5
CV JOINT
ASSEMBLY
FEATURE TREE
DRAWING
PART 1
DRAWING 1
PART 2
DRAWING 2
PART 3
DRAWING 3
CONCLUSION :
- The part components and their respective assemblies were created.
- The 2D drawings of the components were created.
- Necessary files and images were attached.
- The quick return mechanism and cv joint assembly has been done following all the guidelines.