Constant Mesh Gear Box
Constant mesh gearbox is certainly a kind of Transmission where all or most of the gears are always in mesh with each other, instead of a sliding-gear transmission, where engagement is usually obtained by sliding a few of the gears along a shaft into mesh. In a constant-mesh manual gearbox, Equipment ratios are chosen by little Clutches that connect the various gear sets with their shafts so that power can be transmitted through them. The following diagram shows the arrangement of a continuous mesh gear box
Construction and construction and working of constant mesh gearbox functioning of a constant mesh gear box
Constant equipment mesh gearbox employed helical gears for power transmitting. The gears are rigidly fixed in the lay shaft. The gears in output shaft rotates freely without engaging with shaft, hence not transmitting power. The gears in both shafts are generally meshed together.
To activate the gears with output shaft dog clutch is used. the dog clutch is definitely shifted by the seletor fork transferred by gear lever.To supply invert gearing a idler equipment is used.
When the apparatus lever is pushed, the gear selector fork pushes your dog clutch. The dog clutch engages the apparatus and the output shaft, thus power from lay shaft today transmitted to output shaft.
CONSTANT MESH GEARBOX
A continuous mesh transmission is that a form of manual transmission where 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 connection with the acceptable pair of the meshed gears.
A constant mesh transmission typically comes with 4 forward speeds and 1 reverse manual tranny configuration.
Why will we wish Constant Mesh Transmission?
The introduction of initial transmission system i.electronic. sliding mesh tranny was an excellent success in cars trade as currently there was a system which might provide needed torsion and quickness ratios want by the automobile to face the street challenges nevertheless still there have been several vital issues with this gear that raised the question on its performance and responsibility. the problems long-faced were as follows-
The shifting of gears wasn’t an easy task because the shifting needed a special technique that wasn’t in any respect everybody’s cup of tea, a talented driver was necessary for driving such vehicle, the special technique needed being Double-de-clutching.
Note – Double-de-clutching- it’s the technique because the name indicates that needed double engagement and disengagement of clutch for shifting 1 gear.
f i.e. once driver needs to shift the apparatus he preliminary presses the clutch pedal and create the apparatus to the neutral, than once again he releases the clutch pedal and accelerate so as to extend the swiftness of the lay-shaft in order that the meshing of relevant gear will occur, save for he presses the clutch pedal and create the gear lever to the desired gear and unleash the clutch pedal and finally the desired gear is obtained.
Since the gears should be meshed square measure in continuous rotation with a completely different speed compared to the meshing of these gears may cause breakage to the apparatus teethes or continuous wear and tear 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 various kinds 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. Too dog clutches are given on the primary shaft: one between the clutch gear and the next gear; and the other between your first gear and reverse gear. The main shaft is made splined and all 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 is made to slide to the left with the aid of the gear shift lever, it meshes with the clutch gear and the top speed gear is obtained. When the left dog clutch meshes with the next gear on the main shaft, the next speed equipment is achieved. Similarly, by sliding the right-hand dog clutch to the left and correct, the first speed gear and reverse gear are acquired respectively In this kind of gearbox, because all the gears are in constant mesh, they are safe from being damaged and unpleasant grinding audio does not take place while engaging and disengaging them.
Constant mesh gearbox is utilized for the smooth working of a car. They are used to increase the rotating push (Torque); that is accompanied by a reduction in rate. It is a type of manual tranny. The invention of earliest manual equipment system could be traced back again to the nineteenth century. There are multiple equipment ratios present which gives various torque and quickness ratio. Along with this, the reverse mechanism is also present. This manual transmissions which are developed recently contain all of the gears mesh at any provided point of time.
In technical terms, it could be defined as a gearbox where all the gears are generally in circumstances of mesh. The gears remain fixed at their initial positions. The gears will remain engaged all the time. Find out more about its building, working, advantages, drawbacks and applications in this post.
Construction:
It is made up of following components:
1. Counter shaft or Lay Shaft:
This shaft is in direct contact with the clutch and the main shaft. Remember according to the gear ratio, the acceleration of the counter shaft could be much less that the acceleration of the engine. The gear ratio can be explained as the ratio of the teeth of driven equipment to one’s teeth of the driver equipment.
2. Main shaft:
This shaft operates the speed of the automobile. The power is manufactured available to the primary shaft 
through the gears from the counter shaft. That is done in accordance with the gear ratio.
3. Dog clutch:
Dog clutch is particular feature of continuous mesh gearbox. It is utilized for the coupling of any two shafts. This is completed by interference. Using a dog clutch, numerous gears could be locked to the output and input shafts.
4. Gears:
The primary work of the gears is the transmission of power between the shafts. If the apparatus ratio is several, the primary shaft will continue to work at a quickness that is slower compared to the counter shaft, and vice versa. The arrangement of both reverse, along with forward gears, is present.
Working:
Forward gear selection:
From the input shaft, the power starts flowing and is divided into four parts. Each part goes to among the result gears, namely first, second, third and fourth. 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 circulation completes. This happens due to the locking movement of the result shaft.
Reverse gear selection:
The energy will flow from the input shaft to the reverse gears. The energy is after that transmitted from the reverse gear to the invert idler. The idler wheel changes the path of the rotation. In the case of forwarding direction equipment selection, the result gears will rotate in a path opposite to the insight gears. But in the case of invert gear selection, the rotation can be in the same direction as the input shaft.
The steps are taken up to change any gear in the continuous mesh gearbox system:
1. The first step when one really wants to change the gear would be the pressing of the clutch. After this comes the neutral condition of the vehicle to be performed. Proper optimization of the engine’s speed is necessary.
2. After the neutral gear, one moves ahead to the first gear. The first equipment. This process is called dual clutching. Inefficiency in executing the above guidelines might lead to a severe and gnashing sound.
Advantages and Disadvantages of Continuous Mesh Gearbox:
Advantages:
The first and foremost benefit of the constant gear mesh may be the utilization of helical gears. The dual helical gears and the helical gears are extremely beneficial owing to their quieter operating capabilities
There are numerous conditions which can cause harm. In the case of continuous mesh gearbox, any harm is suffered entirely by your dog clutch teeth. One’s teeth belonging to the gear wheels remain intact. This is not the case for sliding mesh equipment box.
The other equipment boxes are noisy and create an undesirable din.
Disadvantages:
It is less efficient than the others due to higher mesh teeth. Skill is required for it.
The double clutch mesh is necessary. This is necessary to have the spinning motions of the shaft.
Application:
A few of the vehicles designed to use this type of gearboxes are farm trucks, motorcycles, and heavy machinery.
In this type of gearbox, all the gears of the primary shaft are in continuous mesh with the corresponding gears of the counter shaft or lay shaft.
Two dog clutches are given on the main shaft i.e. one in between the clutch equipment and the second gear, and the other between the first gear and the reverse gear.
The dog clutch can slide on the shaft and rotate with it. While, all the gears on the counter shaft are rigidly set with it.
As so when the left hand dog clutch was created to slide left by means of the gear change lever, it meshes with the clutch gear and the very best speed gear is obtained. When the remaining hand dog clutch meshes with second gear, the second gear is obtained.
Similarly, by sliding correct hand dog clutch to the left and right, the 1st speed gear and reverse gear are obtained respectively.
In this type of gearbox, all of the gears are in continuous mesh and hence because of this, they are secure from being damaged and irritating grinding sound does not happen while engaging and disengaging.
