Constant Mesh Gear Box
Constant mesh gearbox can be a kind of Transmission where all or the majority of the gears are always in mesh with one another, instead of a sliding-gear transmission, in which engagement is certainly obtained by sliding a few of the gears along a shaft into mesh. In a constant-mesh manual gearbox, Equipment ratios are selected by little Clutches that connect the many gear sets with their shafts so that power can be transmitted through them. The next diagram shows the set up of a constant mesh gear box
Construction and functioning of a constant mesh gear box
Constant gear mesh gearbox employed helical gears for power transmitting. The gears are rigidly fixed in the lay shaft. The gears in result shaft rotates freely without engaging with shaft, therefore not really transmitting power. The gears in both shafts are always meshed together.
To activate the gears with result shaft dog clutch can be used. the dog clutch is certainly shifted by the seletor fork transferred by gear lever.To provide invert gearing a idler gear is used.
When the gear lever is pushed, the gear selector fork pushes your dog clutch. Your dog clutch engages the apparatus and the output shaft, thus power from lay shaft right now transmitted to result shaft.
CONSTANT MESH GEARBOX
A continuous mesh transmission is that 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 products named dog clutches square measure introduced which helps in transmittal the required output to the most shaft by creating contact with the acceptable pair of the meshed gears.
A constant mesh transmission typically includes 4 forward speeds and 1 reverse manual transmitting configuration.
Why will we wish Constant Mesh Transmission?
The introduction of initial transmission system i.e. sliding mesh tranny was a great success in vehicles trade as currently there was a system which can offer needed torsion and swiftness ratios desire by the vehicle to face the street challenges nevertheless still there have been several vital problems with this equipment that raised the question on its performance and responsibility. the problems long-faced were as follows-
The shifting of gears wasn’t a simple task since the shifting needed a particular technique that wasn’t in any respect 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 because the name indicates that needed dual engagement and disengagement of clutch for shifting one gear.
f i.electronic. once driver must shift the gear he preliminary presses the clutch pedal and produce the apparatus to the neutral, than once more 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 happen, save for he presses the clutch pedal and create the apparatus lever to the required 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 those gears may cause breakage to the gear teethes or continuous deterioration is there.
The shifting of gears is actually 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 Constant 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 provided on the main shaft: one construction and working of constant mesh gearbox between your clutch gear and the second gear; and the various other between your first gear and invert gear. The main shaft is made splined and all the gears are free to move onto it. Dog clutches can slide on the main shaft and rotates with it. All of 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 remaining dog clutch meshes with the second gear on the main shaft, the second speed equipment is achieved. Likewise, by sliding the right-hand dog clutch to the left and correct, the first speed equipment and reverse gear are attained respectively In this type of gearbox, because all of the gears are in constant mesh, they are secure from being damaged and unpleasant grinding sound does not occur while engaging and disengaging them.
Continuous mesh gearbox is used for the smooth functioning of an automobile. They are accustomed to increase the rotating power (Torque); that is accompanied by a decrease in velocity. It is a kind of manual tranny. The invention of earliest manual equipment system could be traced back to the nineteenth century. There are multiple gear ratios present which gives various torque and swiftness ratio. Along with this, the reverse mechanism can be present. This manual transmissions which are developed lately contain all the gears mesh at any provided point of time.
In specialized terms, it can be defined as a gearbox in which all the gears are usually in a state of mesh. The gears remain fixed at their first positions. The gears will remain engaged at all times. Find out more about its building, working, advantages, disadvantages and applications in this article.
Construction:
It really 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 swiftness of the counter shaft could be less that the acceleration of the engine. The apparatus ratio can be defined as the ratio of the teeth of driven gear to the teeth of the driver equipment.
2. Main shaft:
This shaft operates the speed of the automobile. 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 constant mesh gearbox. It can be used for the coupling of any two shafts. This is carried out by interference. Using a dog clutch, different gears could be locked to the output and input shafts.
4. Gears:
The primary work of the gears may be the transmission of power between the shafts. If the apparatus ratio is more than one, 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 energy starts flowing and is divided into four parts. Each component goes to among the output gears, namely 1st, second, third and fourth. Gear ratios can be acquired for each of these. This could be done by the correct sliding 
of dog clutch over one’s teeth of the chosen gearwheel. After this the path of the energy movement completes. This happens due to the locking motion of the output shaft.
Reverse gear selection:
The energy will flow from the input shaft to the reverse gears. The energy is after that transmitted from the invert gear to the reverse idler. The idler wheel changes the direction of the rotation. Regarding forwarding direction equipment selection, the result gears will rotate in a direction opposite to the insight gears. However in the case of invert gear selection, the rotation can be in the same path as the insight shaft.
The steps are taken to change any gear in the continuous mesh gearbox system:
1. The first step when one wants to change the gear would be the pressing of the clutch. Following this comes the neutral state of the automobile 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 equipment. This process is known as dual clutching. Inefficiency in performing the above methods might lead to a severe and gnashing sound.
Benefits and drawbacks of Continuous Mesh Gearbox:
Advantages:
The first and foremost benefit of the constant gear mesh is the usage of helical gears. The dual helical gears and the helical gears are extremely beneficial owing to their quieter operating capabilities
There are many conditions which might cause harm. Regarding constant mesh gearbox, any harm is suffered completely by the dog clutch teeth. The teeth belonging to the gear wheels stay intact. This is simply not the case for sliding mesh equipment box.
The other gear boxes are noisy and create an undesirable 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 possess the spinning movements of the shaft.
Application:
A few of the vehicles designed to use this type of gearboxes are farm trucks, motorcycles, and large machinery.
In this kind of gearbox, all the gears of the main shaft are in continuous mesh with the corresponding gears of the counter shaft or lay shaft.
Two dog clutches are provided on the primary shaft i.electronic. one in between the clutch equipment and the next gear, and the other 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 fixed with it.
As so when the left hand dog clutch was created to slide to the 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 hands dog clutch meshes with second equipment, 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 constant mesh and hence because of this, they are safe from being damaged and irritating grinding sound will not happen while engaging and disengaging.