Constant Mesh Gear Box
Constant mesh gearbox is a type of Transmission in which all or most of the gears are always in mesh with one another, instead of a sliding-gear transmission, in which engagement is obtained by sliding some of the gears along a shaft into mesh. In a constant-mesh manual gearbox, Gear ratios are selected by little Clutches that connect the various gear sets with their shafts so that power is usually transmitted through them. The following diagram shows the arrangement of a continuous mesh gear box
Construction and functioning of a continuous mesh gear box
Constant equipment mesh gearbox employed helical gears for power transmitting. The gears are rigidly set in the lay shaft. The gears in output shaft rotates freely without engaging with shaft, therefore not transmitting power. The gears in both shafts are constantly meshed together.
To engage the gears with result shaft dog clutch can be used. the dog clutch is certainly shifted by the seletor fork shifted by gear lever.To provide reverse gearing a idler gear is used.
When the gear lever is pushed, the apparatus selector fork pushes your dog clutch. The dog clutch engages the apparatus and the result shaft, thus power from lay shaft now transmitted to result shaft.
CONSTANT MESH GEARBOX
A continuous mesh transmission is a type of manual transmission where sliding gears from the sliding mesh gearbox is replaced with the constantly meshed combines of gears and also the new shifting devices named dog clutches sq . measure introduced which assists in transmittal the required output to the the majority of shaft by creating connection with the acceptable pair of the meshed gears.
A continuous 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.e. sliding mesh tranny was a great success in cars trade as currently there was a system which might provide needed torsion and quickness ratios desire by the vehicle to face the road challenges nevertheless still there were several vital issues with this gear that raised the issue on its effectiveness and responsibility. the issues long-faced were as follows-
The shifting of gears wasn’t an easy task because the shifting needed a particular technique that wasn’t in any respect everybody’s cup of tea, a talented driver was needed 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 dual engagement and disengagement of clutch for shifting one particular gear.
f i.electronic. once driver must shift the apparatus he preliminary presses the clutch pedal and produce the gear to the neutral, than once more he releases the clutch pedal and accelerate so as to extend the acceleration of the lay-shaft to ensure that the meshing of relevant gear will happen, save for he presses the clutch pedal and produce the gear lever to the desired gear and unleash the clutch pedal and at last the desired gear is obtained.
Since the gears are to be meshed square measure in continuous rotation with a totally different speed than the meshing of these gears may cause breakage to the gear teethes or continuous wear and tear is there.
The shifting of gears is actually a terribly clamant method.High maintenance is needed 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 Constant Mesh Gearbox gearbox, all gears of the primary shaft are in constantly meshed with the corresponding gears of the layshaft or countershaft. As well dog clutches are provided on the primary shaft: one between the clutch gear and the second gear; and the other between your first gear and reverse gear. The main shaft is manufactured splined and all the gears are absolve to move on it. Dog clutches can slide on the main shaft and rotates with it. All the gears on the countershaft are permanently fixed with it.
When the left dog clutch was created to slide to the left with the help of the apparatus shift lever, it meshes with the clutch gear and the very best speed gear is obtained. When the left dog clutch meshes with the second gear on the primary shaft, the next speed equipment is achieved. Similarly, by sliding the right-hand dog clutch to the left and right, the first speed gear and reverse gear are attained respectively In this type of gearbox, because all the gears are in continuous mesh, they are safe from being damaged and unpleasant grinding sound does not occur while engaging and disengaging them.
Constant mesh gearbox is used for the smooth operating of an automobile. They are accustomed to increase the rotating power (Torque); this is accompanied by a reduction in acceleration. It is a type of manual transmission. The invention of earliest manual gear system could be traced back to the nineteenth century. There are multiple gear ratios present which provides various torque and speed ratio. Additionally, the reverse mechanism can be present. This manual transmissions which are developed lately 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 usually in a state of mesh. The gears remain fixed at their unique positions. The gears will stay engaged all the time. Find out more about its structure, working, advantages, drawbacks and applications in this article.
Construction:
It is made up of following components:
1. Counter shaft or Lay Shaft:
This shaft is in direct connection with the clutch and the primary shaft. Remember according to the gear ratio, the speed of the counter shaft could be much less that the acceleration of the engine. The apparatus ratio can be defined as the ratio of the teeth of driven gear 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. This is done in accordance with the gear ratio.
3. Dog clutch:
Dog clutch is special feature of continuous mesh gearbox. It is utilized for the coupling of any two shafts. This is carried out by interference. Utilizing 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 your shafts. If the apparatus ratio is more than one, the primary shaft will continue to work at a rate that is slower compared to the counter shaft, and vice versa. The set up of both reverse, along with forward gears, exists.
Working:
Forward gear selection:
From the input shaft, the power starts flowing and is divided into four parts. Each component goes to one of the output gears, namely 1st, second, third and fourth. Gear ratios can be acquired for each of them. This is often done by the correct sliding of dog clutch over one’s teeth of the chosen gearwheel. After this the path of the energy stream completes. This happens because of the locking movement of the result shaft.
Reverse gear selection:
The power will flow from the input shaft to the reverse gears. The power is then transmitted from the reverse gear to the reverse idler. The idler wheel changes the direction of the rotation. In the case of forwarding direction gear selection, the output gears will rotate 
in a direction opposite to the insight gears. But in the case of invert gear selection, the rotation is usually 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 rung on the construction and working of constant mesh gearbox ladder when one really wants to change the gear will be the pressing of the clutch. After this comes the neutral condition of the vehicle to be achieved. Proper optimization of the engine’s speed is required.
2. After the neutral equipment, one moves forwards to the first equipment. The first equipment. This process is known as double clutching. Inefficiency in carrying out the above steps might result in a severe and gnashing sound.
Advantages and Disadvantages of Continuous Mesh Gearbox:
Advantages:
The first and foremost advantage of the constant gear mesh is the usage of helical gears. The dual helical gears and the helical gears are really beneficial owing to their quieter operating capabilities
There are many conditions which might cause harm. In the case of continuous mesh gearbox, any damage is suffered completely by your dog clutch teeth. One’s teeth belonging to the gear tires stay intact. This is simply not the case for sliding mesh gear box.
The other gear boxes are noisy and create an undesirable din.
Disadvantages:
It really 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 movements of the shaft.
Application:
Some of the vehicles designed to use this kind of gearboxes are farm trucks, motorcycles, and heavy machinery.
In this type of gearbox, all of 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 main shaft i.electronic. one in between the clutch gear and the second gear, and the other between the first equipment and the reverse equipment.
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 hand dog clutch is made to slide to the left by means of the gear change lever, it meshes with the clutch equipment and the very best speed gear is obtained. When the left hand dog clutch meshes with second gear, the second gear is obtained.
Similarly, by sliding right hand dog clutch to the left and right, the first speed gear and reverse gear are obtained respectively.
In this kind of gearbox, all the gears are in continuous mesh and hence because of this, they are safe from being damaged and irritating grinding sound does not happen while engaging and disengaging.
