Constant Mesh Gear Box
Constant mesh gearbox is 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, where engagement is 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 to ensure that power is certainly transmitted through them. The next diagram shows the set up of a constant mesh gear box
Construction and working of a continuous mesh gear box
Constant gear mesh gearbox employed helical gears for power tranny. The gears are rigidly set in the lay shaft. The gears in construction and working of constant mesh gearbox output shaft rotates freely without engaging with shaft, therefore not transmitting power. The gears in both shafts are constantly meshed together.
To activate the gears with result shaft dog clutch can be used. the dog clutch is definitely shifted by the seletor fork transferred by gear lever.To supply reverse gearing a idler equipment is used.
When the gear lever is pushed, the gear selector fork pushes the dog clutch. The dog clutch engages the gear and the result shaft, thus power from lay shaft now transmitted to output shaft.
CONSTANT MESH GEARBOX
A continuous mesh transmission is that 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 square measure introduced which helps in transmittal the desired output to the many shaft by creating connection with the acceptable couple of the meshed gears.
A continuous 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.electronic. sliding mesh transmission was a great success in vehicles trade as presently there is a system which can provide needed torsion and velocity ratios desire by the vehicle to face the road challenges nevertheless still there were several vital issues with this equipment 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 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 a single gear.
f i.electronic. once driver must shift the apparatus he initial presses the clutch pedal and generate the apparatus to the neutral, than once again he releases the clutch pedal and accelerate so as to extend the speed 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 equipment 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 completely different speed compared to 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 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 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 between the clutch equipment and the next gear; and the other between your first gear and invert gear. The primary 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 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 help of the apparatus shift lever, it meshes with the clutch gear and the top speed gear is obtained. When the left dog clutch meshes with the second gear on the main shaft, the second speed gear is achieved. Likewise, by sliding the right-hand dog clutch left and right, the first speed gear and reverse equipment are obtained respectively In this kind of gearbox, because all the gears are in continuous mesh, they are safe from being broken and unpleasant grinding sound does not occur 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 decrease in swiftness. 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 gear ratios present which provides various torque and acceleration ratio. Additionally, 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 specialized terms, it can be defined as a gearbox in which all the gears are constantly in a state of mesh. The gears remain fixed at their initial positions. The gears will stay engaged at all times. Learn more about its building, working, advantages, disadvantages and applications in this article.
Construction:
It 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. Remember according to the gear ratio, the velocity of the counter shaft could be less that the velocity of the engine. The gear 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 automobile. The power is manufactured available to the main shaft through the gears from the counter shaft. That is done relative to the gear ratio.
3. Dog clutch:
Dog clutch is unique feature of constant mesh gearbox. It is utilized for the coupling of any two shafts. That is carried out by interference. Using a dog clutch, various 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 your shafts. If the apparatus ratio is several, the main shaft will work at a rate that is slower compared to the counter shaft, and vice versa. The set up of both reverse, as well as forward gears, is present.
Working:
Forward gear selection:
From the input shaft, the power starts flowing and is split into four parts. Each component 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 correct sliding of dog clutch over one’s teeth of the chosen gearwheel. After this the path of the energy flow completes. This happens due to the locking motion of the output shaft.
Reverse gear selection:
The power 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 path of the rotation. In the case of forwarding direction equipment selection, the result gears will rotate in a direction opposite to the insight gears. However in the case of invert equipment selection, the rotation is certainly in the same path as the insight shaft.
The steps are taken to change any gear in the constant mesh gearbox system:
1. The first rung on the ladder when one 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 necessary.
2. After the neutral equipment, one moves ahead to the first gear. The first equipment. This process is called double clutching. Inefficiency in carrying out the above steps might lead to a harsh and gnashing sound.
Advantages and Disadvantages of Constant Mesh Gearbox:
Advantages:
The first and foremost advantage of the constant gear mesh is the utilization of helical gears. The dual helical gears and the helical gears are extremely beneficial owing to their quieter operating capabilities
There are various conditions which can cause harm. In the case of constant mesh gearbox, any harm is suffered entirely by your dog clutch teeth. One’s teeth belonging to the apparatus tires stay intact. This is simply not the case for sliding mesh equipment box.
The other equipment boxes are noisy and create an unwanted din.
Disadvantages:
It really is less efficient compared to the others because of higher mesh teeth. Skill is necessary for it.
The dual clutch mesh is necessary. This is required to possess the spinning motions of the shaft.
Application:
Some of the vehicles designed to use this kind of gearboxes are farm trucks, motorcycles, and heavy machinery.
In this kind 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 primary shaft i.electronic. one in between the clutch equipment and the second gear, and the additional 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 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 very best speed gear is obtained. When the left hand dog clutch meshes with second gear, the next 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 type of gearbox, all of the gears are in continuous mesh and hence for this reason, they are safe from being damaged and irritating grinding sound will not happen while engaging and disengaging.