Constant Mesh Gear Box
Constant mesh gearbox can be a type of Transmission where all or the majority of the gears are always in mesh with each other, instead of a sliding-gear transmission, where engagement is certainly obtained by sliding some of the gears along a shaft into mesh. In a constant-mesh manual gearbox, Gear ratios are chosen by small Clutches that connect the various gear sets with their shafts so that power can be transmitted through them. The construction and working of constant mesh gearbox following diagram shows the set up of a constant mesh gear box
Construction and operating of a continuous mesh gear box
Constant equipment mesh gearbox employed helical gears for power transmission. The gears are rigidly set 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 usually meshed together.
To engage the gears with output shaft dog clutch can be used. the dog clutch is certainly shifted by the seletor fork moved by gear lever.To provide reverse gearing a idler equipment is used.
When the apparatus lever is pushed, the gear selector fork pushes the dog clutch. Your dog clutch engages the gear and the output shaft, therefore power from lay shaft right now transmitted to result shaft.
CONSTANT MESH GEARBOX
A continuous mesh transmission is a kind 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 gadgets named dog clutches sq . measure introduced which helps in transmittal the required output to the many shaft by creating contact with the acceptable couple of the meshed gears.
A continuous mesh transmission typically includes 4 forward speeds and 1 reverse manual transmission configuration.
Why will we wish Constant Mesh Transmission?
The introduction of initial transmission system i.e. sliding mesh transmission was a great success in vehicles trade as currently there is a system which can offer needed torsion and velocity ratios really want by the automobile to face the street challenges nevertheless still there have been several vital issues with this equipment that raised the question on its performance and responsibility. the issues long-faced were as follows-
The shifting of gears wasn’t an easy task since the shifting needed a special technique that wasn’t whatsoever everybody’s cup of tea, a talented driver was necessary for generating 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 gear he initial 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 rate of the lay-shaft to ensure that the meshing of applicable gear will take place, save for he presses the clutch pedal and produce the apparatus lever to the desired gear and unleash the clutch pedal and finally 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 those gears will 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 primary shaft are in constantly meshed with the corresponding gears of the layshaft or countershaft. Too dog clutches are provided on the main 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 the gears are free to move on it. Dog clutches can slide on the primary 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 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 next gear on the main 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 acquired respectively In this kind of gearbox, because all the gears are in continuous mesh, they are secure from being broken and unpleasant grinding audio does not occur while engaging and disengaging them.
Constant mesh gearbox can be used for the smooth functioning of a car. They are used to increase the rotating force (Torque); that is accompanied by a decrease in velocity. It is a kind of manual transmission. The invention of earliest manual equipment system could be traced back to the nineteenth century. There are multiple gear ratios present which provides various torque and rate ratio. Additionally, the reverse mechanism is also present. This manual transmissions which are developed recently contain all the gears mesh at any provided point of time.
In technical terms, it can be defined as a gearbox in which all of the gears are constantly in circumstances of mesh. The gears remain fixed at their primary positions. The gears will stay engaged at all times. Learn 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 contact with the clutch and the primary shaft. Keeping in mind 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 defined as the ratio of the teeth of driven gear to one’s teeth of the driver gear.
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. That is done in accordance with the gear ratio.
3. Dog clutch:
Dog clutch is unique feature of constant mesh gearbox. It can be used for the coupling of any two shafts. That is done by interference. Using a dog clutch, numerous gears can be locked to the result 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 speed that is slower than the counter shaft, and vice versa. The arrangement of both reverse, along with forward gears, exists.
Working:
Forward gear selection:
From the input shaft, the energy starts flowing and is split into four parts. Each component goes to one of the output gears, namely 1st, second, third and fourth. Gear ratios can be obtained for each of them. 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 circulation 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 after that transmitted from the invert gear to the invert idler. The idler wheel changes the path of the rotation. Regarding forwarding direction gear selection, the output gears will rotate in a path opposite to the input gears. But in the case of invert gear selection, the rotation can be in the same direction as the insight shaft.
The steps are taken to change any gear in the continuous mesh gearbox system:
1. The first rung on the ladder when one really wants to modify 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 gear, one moves ahead to the first equipment. The first gear. This process is known as double clutching. Inefficiency in executing the above measures might lead to a harsh and gnashing sound.
Benefits and drawbacks of Constant Mesh Gearbox:
Advantages:
The first and foremost benefit of the continuous gear mesh is the usage of helical gears. The dual helical gears and the helical gears are really beneficial due to their quieter operating capabilities
There are many conditions which can cause harm. Regarding continuous mesh gearbox, any harm is suffered completely by your dog clutch teeth. The teeth belonging to the apparatus tires stay intact. This is not the case for sliding mesh equipment box.
The other gear 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 necessary for it.
The dual clutch mesh is required. This is required to possess the spinning actions of the shaft.
Application:
A few of the vehicles designed to use this type of gearboxes are farm trucks, motorcycles, and weighty machinery.
In this kind of gearbox, all the gears of the primary 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.e. one among the clutch equipment and the next 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 fixed with it.
As and when the left hands dog clutch was created to slide left by means of the gear shift lever, it meshes with the clutch equipment and the top speed equipment is obtained. When the left hands dog clutch meshes with second gear, the second gear is obtained.
Similarly, by sliding correct hand dog clutch left and right, the 1st speed gear and reverse gear are obtained respectively.
In this type of gearbox, all the gears are in constant mesh and hence for this reason, they are safe from being damaged and irritating grinding sound will not take place while engaging and disengaging.