Constant Mesh Gear Box
Constant mesh gearbox is certainly a type of Transmission in which all or most of the gears are always in mesh with each other, instead of a sliding-gear transmission, in which engagement is usually obtained by sliding some of the gears along a shaft into mesh. In a constant-mesh manual gearbox, Equipment ratios are chosen by small Clutches that connect the many gear sets to their shafts so that power can be transmitted through them. The following diagram shows the set up of a continuous mesh gear box
Construction and operating of a continuous mesh gear box
Constant gear mesh gearbox employed helical gears for power transmission. The gears are rigidly fixed in the lay shaft. The gears in result shaft rotates freely without engaging with shaft, thus not transmitting power. The gears in both shafts are constantly meshed together.
To activate the gears with result shaft dog clutch is used. the dog clutch is certainly shifted by the seletor fork moved by gear lever.To provide invert gearing a idler gear is used.
When the gear lever is pushed, the apparatus selector fork pushes the dog clutch. Your dog clutch engages the apparatus and the result shaft, therefore power from lay shaft today transmitted to output shaft.
CONSTANT MESH GEARBOX
A constant mesh transmission is a form of manual transmission in which sliding gears from the sliding mesh gearbox is replaced with the constantly meshed combines of gears as well as the new shifting devices named dog clutches sq . measure introduced which helps in transmittal the desired output to the many shaft by creating contact with the acceptable couple of the meshed gears.
A constant mesh transmission typically includes 4 forward speeds and 1 reverse manual transmitting configuration.
Why will we want Constant Mesh Transmission?
The introduction of initial transmission system i.electronic. sliding mesh transmission was a great success in vehicles trade as currently there was a system which can offer needed torsion and quickness ratios want by the automobile to face the road challenges however still there have been several vital problems with this gear that raised the question on its effectiveness and responsibility. the issues long-faced were as follows-
The shifting of gears wasn’t an easy task since the shifting needed a particular technique that wasn’t whatsoever everybody’s cup of tea, a talented driver was necessary for traveling such vehicle, the special technique needed being Double-de-clutching.
Note – Double-de-clutching- it’s the technique since the name indicates that needed dual engagement and disengagement of clutch for shifting 1 gear.
f i.electronic. once driver must shift the apparatus he preliminary presses the clutch pedal and generate the apparatus to the neutral, than once more he releases the clutch pedal and accelerate in order to extend the rate of the lay-shaft in order that the meshing of relevant gear will take place, save for he presses the clutch pedal and produce the apparatus lever to the required gear and unleash the clutch pedal and at last the required gear is obtained.
Since the gears should be meshed square measure in continuous rotation with a completely different speed than the meshing of these gears will cause breakage to the gear teethes or continuous deterioration is there.
The shifting of gears could be a terribly clamant method.High maintenance is necessary as slippy and meshing of gears causes resistance to wear of shafts and gears.
MAIN PARTS
Clutch Shaft.
Lay Shaft or counter Shaft.
Main Shaft.
Dog clutch.
Gears.
There are different types of gears with both spur and helical gears like:
Clutch gear.
First gear.
Second gear.
Reverse gear.
WORKING PRINCIPLE:
In Continuous Mesh Gearbox gearbox, all gears of the main shaft are in constantly meshed with the corresponding gears of the layshaft or countershaft. As well dog clutches are given on the primary shaft: one between the clutch equipment and the second gear; and the various other between the first gear and reverse gear. The main shaft is made splined and all of the gears are free to move on it. Dog clutches can slide on the main shaft and rotates with it. All the gears on the countershaft are completely fixed with it.
When the left dog clutch was created to slide to the left by using the apparatus shift lever, it meshes with the clutch gear and the top speed gear is obtained. When the remaining dog clutch meshes with the next gear on the main shaft, the second speed equipment is achieved. Likewise, by sliding the right-hand dog clutch left and right, the first speed equipment and reverse equipment are obtained respectively In this type of gearbox, because all of the gears are in continuous mesh, they are safe from being broken and unpleasant grinding audio does not take place while engaging and disengaging them.
Constant mesh gearbox can be used for the smooth operating of an automobile. They are used to increase the rotating drive (Torque); this is accompanied by a reduction in quickness. It is a type of manual tranny. The invention of earliest manual gear system can be traced back again to the nineteenth century. There are multiple equipment ratios present which provides various torque and rate ratio. Additionally, the reverse mechanism is also present. This manual transmissions which are developed lately contain all the gears mesh at any provided point of time.
In technical terms, it can be defined as a gearbox where all of the gears are usually in a state of mesh. The gears stay fixed at their initial positions. The gears will remain engaged all the time. Find out more about its structure, working, advantages, disadvantages and applications in this article.
Construction:
It really is made up of subsequent components:
1. Counter shaft or Lay Shaft:
This shaft is in direct connection with the clutch and the main shaft. Remember according to the gear ratio, the swiftness of the counter shaft may be less that the swiftness of the engine. The apparatus ratio can be explained as the ratio of the teeth of driven gear to the teeth of the driver gear.
2. Main shaft:
This shaft operates the speed of the 
vehicle. The power is made available to the primary shaft through the gears from the counter shaft. This is done relative to the gear ratio.
3. Dog clutch:
Dog clutch is special feature of continuous mesh gearbox. It is used for the coupling of any two shafts. This is carried out by interference. Using a dog clutch, numerous gears can be locked to the result and input shafts.
4. Gears:
The main work of the gears is the transmission of power between the shafts. If the apparatus ratio is more than one, the main shaft will work at a acceleration that is slower than the counter shaft, and vice versa. The arrangement of both reverse, as well as forward gears, exists.
Working:
Forward gear selection:
From the input shaft, the power starts flowing and is split into four parts. Each part goes to one of the result gears, namely first, second, third and 4th. Gear ratios can be obtained for each of these. This is often done by the proper sliding of dog clutch over the teeth of the chosen gearwheel. After this the path of the energy stream completes. This happens due to the locking motion of the result shaft.
Reverse gear selection:
The energy will flow from the input shaft to the reverse gears. The power is then transmitted from the reverse gear to the invert idler. The idler wheel changes the direction of the rotation. In the case of forwarding direction gear selection, the result gears will rotate in a path opposite to the input gears. However in the case of reverse gear selection, the rotation can be in the same direction as the insight shaft.
The steps are taken up to change any gear in the continuous mesh gearbox system:
1. The first rung on the ladder when one wants to modify the gear would be the pressing of the clutch. Following this comes the neutral state of the vehicle to be achieved. Proper optimization of the engine’s speed is necessary.
2. After the neutral equipment, one moves ahead to the first equipment. The first gear. This process is known as dual clutching. Inefficiency in carrying out the above methods might result in a harsh and gnashing sound.
Benefits and drawbacks of Continuous Mesh Gearbox:
Advantages:
The first and foremost advantage of the constant gear mesh may be the utilization of helical gears. The double helical gears and the helical gears are really beneficial owing to their quieter operating capabilities
There are various conditions which can cause harm. In the case of continuous mesh gearbox, any harm is suffered entirely by your dog clutch teeth. The teeth belonging to the apparatus wheels stay intact. This is simply not the case for sliding mesh gear box.
The other equipment boxes are noisy and create an unwanted din.
Disadvantages:
It really is less efficient compared to the others due to higher mesh teeth. Skill is required for it.
The dual clutch mesh is required. This is necessary to have the spinning motions of the shaft.
Application:
Some of the vehicles which use this type of gearboxes are farm trucks, motorcycles, and large machinery.
In this type of gearbox, all the gears of the main shaft are in constant mesh with the corresponding gears of the counter shaft or lay shaft.
Two dog clutches are given on the primary shaft i.electronic. one among the clutch equipment and the second gear, and the additional between the first equipment and the reverse gear.
Your dog clutch can slide on the shaft and rotate with it. While, all of the gears on the counter shaft are rigidly set with it.
As so when the left hands dog clutch was created to slide to the left by means of the apparatus shift lever, it meshes with the clutch gear and the very best speed equipment is obtained. When the left hands dog clutch meshes with second equipment, the second gear is obtained.
Similarly, by sliding right hand dog clutch left and right, the initial speed gear and reverse gear are obtained respectively.
In this type of gearbox, all the gears are in continuous mesh and hence for this reason, they are safe from being damaged and irritating grinding sound will not occur while engaging and disengaging.
We have more information regarding construction and working of constant mesh gearbox.
