A 5mm thick metal plate was taken. This plate was then cut to 440x330mm using a cutter.
Then 4 slots of 70x30mm were made by using the same cutter. Then the bracket supports of hollow square cross section were made of 55mm height. These supports were then welded to this machine bed
The cylinder head supports are designed to accommodate the cylinder head while the valve lapping process. This extra feature is added to the design because it is hard to move a cylinder head when the cylinder head needed to be adjusted to a different position.
Since this cylinder head supports are movable along the machine bed, it is very easy to adjust the cylinder head position.
Steel column of square cross section
A steel column of square cross section of area 625mm2 was taken. This column was cut into 4 pieces of 160mm length & 2 pieces of 190 mm length. Then these were welded as required (C – Column). Then holes of 10mm were drilled. Then this column was welded with plates as a base support for this column.
Machine stand is assembled to the machine bed in one end. Other end of the machine stand is the mounting for the valve lapping mechanism and also the holding bracket for High torque, heavy duty 12V DC gear motor, mounted near the same end. Therefore allowing the access to any valve position of a cylinder head placed on cylinder head supports. The load generated while the valve lapping process is transmitted to machine bed through the machine stand and the integrity of the structure is a very important factor to consider when designing. Lower end of machine stand which is assembled to machine bed is one of the areas of the machine with highest stress concentration. The assembly area of the machine stand to machine bed is subjected to loads from machine bed surface and valve lapping process.
A steel column of square cross section of area 625mm2 & 500mm2 was taken. First column was cut into 2 pieces of 600mm length & 120 mm length. Then the secod column and short piece of first column were welded as required (C – Column). Then holes of 6mm(11nos.) were drilled.
This bracket holds the motor which transmit motion to the cam and as the cam subjects to some amount of torque, the same torque is transmitted though the motor to the bracket and therefore bracket is also subjected to the same torque.
Cam is the main part responsible for the vertical movement of the cleaning mechanism. Actually a cam works as a system that consist with a follower i.e a cam drive and a follower system. The vertical motion is gained by the valve lapping mechanism when the cam is rotated by the rotary motion. High torque and heavy duty DC motor which is the cam drive and the rotary motion is then converted in to linear motion using the shape of cam nose and it is transmitted to the valve mechanism through the cam follower. The vertical motion of the valve lapping mechanism helps to break the contact between valve seat and the corresponding surface of a cylinder head. The importance of this action the rotary motion is converted into linear motion. Cam follower is tensioned using a spring in the valve lapping mechanism and as the cam rotates, follower gain space to move upwards and when the cam nose area returns follower move downwards creating a linear motion. Also during the cleaning this mechanism allows the cleaning tool to rotate and move in linear direction , resulting into increase in cleaning efficiency.
Cam systems are classified using a standard classification method. Following text includes the classification of the cam system used in the valve lapping machine.
Spring constraint – The contact between follower and cam profile is maintained by spring. The valve lapping machine for internal combustion engines is mainly consist of three main units. The base, the sliding stand and the valve lapping mechanism. The next section of this text is about the parts and operations of the valve lapping mechanism. Parts that belong to the valve lapping mechanism are upper spring mounting bracket, tension spring, lower spring mounting bracket.
Tension spring is the link between upper mounting bracket and lower mounting bracket. They are connected by welding both ends of the spring to the two brackets.
Fixing of engine valves to the machine in order to lap them is another important task that has to be completed before the valve lapping process begins. This small screw is the first part of the unit designed to hold any kind of valve.
This is one of the most important parts in this machine. Most of the valve lapping power tools and valve lapping sticks doesn’t have an effective valve holding unit. Due to that reason, sometimes while the valve lapping process is going on, the engine valve disconnects from the valve holding unit. This is a real inconvenience. To prevent that from happening, valve lapping machine for IC engines has a special valve holding piece. Valve holding piece that can be either assembled to the valve holding piece mounting screw or the extension piece. The head of this part is made from steel and body is made from natural rubber since natural rubber has the best elasticity of all rubber types. The head and the body is merged together using an industrial grade adhesive.The specialty about these valve holding pieces are that there are 5 types of valve holding pieces designed to be compatible with a wide range of engine valves. Given below is the 5 categories of valve holding pieces and the stem diameter each category can handle.
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