Constant Mesh Gear Box
Constant mesh gearbox is definitely a kind of Transmission in which all or the majority 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, Gear ratios are selected by little Clutches that connect the various gear sets with their shafts to ensure that power is usually transmitted through them. The next diagram shows the arrangement of a continuous mesh gear box
Construction and operating 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 output shaft rotates freely without engaging with shaft, therefore not transmitting power. The gears in both shafts are generally meshed together.
To activate the gears with output shaft dog clutch can be used. the dog clutch is shifted by the seletor fork shifted by gear lever.To supply invert gearing a idler gear is used.
When the apparatus lever is pushed, the apparatus selector fork pushes your dog clutch. Your dog clutch engages the gear and the result shaft, therefore power from lay shaft today transmitted to result shaft.
CONSTANT MESH GEARBOX
A constant mesh transmission is a kind of manual transmission in which sliding gears from the sliding mesh gearbox is construction and working of constant mesh gearbox replaced with the constantly meshed combines of gears as well as the new shifting gadgets named dog clutches square measure introduced which helps in transmittal the required output to the most shaft by creating connection with the acceptable couple of the meshed gears.
A constant mesh transmission typically comes with 4 forward speeds and 1 reverse manual tranny configuration.
Why will we want Constant Mesh Transmission?
The introduction of initial transmission system i.e. sliding mesh transmitting was an excellent success in vehicles trade as currently there is a system which might provide needed torsion and velocity ratios really want by the vehicle to face the road challenges however still there have been 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 a simple task because the shifting needed a particular technique that wasn’t whatsoever everybody’s cup of tea, a talented driver was needed 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 double engagement and disengagement of clutch for shifting a single gear.
f i.electronic. once driver must shift the gear he initial presses the clutch pedal and produce the gear to the neutral, than once more he releases the clutch pedal and accelerate in order to extend the quickness of the lay-shaft in order that the meshing of applicable gear will take place, save for he presses the clutch pedal and generate 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 totally different speed compared to the meshing of those 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 different types 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. As well dog clutches are given on the main shaft: one between your clutch equipment and the second gear; and the various other between the 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 the gears on the countershaft are completely fixed with it.
When the left dog clutch is made to slide left with the aid 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 left and right, the first speed equipment and reverse gear are acquired respectively In this kind of gearbox, because all the gears are in continuous mesh, they are safe from being damaged and unpleasant grinding sound does not happen while engaging and disengaging them.
Constant mesh gearbox is used for the smooth working of an automobile. They are accustomed to increase the rotating pressure (Torque); that is accompanied by a reduction in rate. It is a type of manual transmission. The invention of earliest manual equipment system can be traced back again to the nineteenth century. There are multiple equipment ratios present which provides various torque and velocity 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 technical terms, it can be defined as a gearbox where all the gears are at all times in a state of mesh. The gears remain fixed at their original positions. The gears will remain 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 connection with the clutch and the main shaft. Keeping in mind according to the equipment ratio, the speed of the counter shaft could be less that the velocity of the engine. The apparatus ratio can be explained as the ratio of one’s 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 made available to the main shaft through the gears from the counter shaft. That 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. That is completed by interference. Utilizing a dog clutch, different gears can be locked to the output and input shafts.
4. Gears:
The main work of the gears is the transmission of power between the shafts. If the gear ratio is several, the primary shaft will continue to work at a acceleration that is slower than the counter shaft, and vice versa. The arrangement of both reverse, as well as 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 among the result gears, namely initial, 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 one’s teeth of the selected 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 power will flow from the input shaft to the reverse gears. The energy is then transmitted from the invert gear to the invert idler. The idler wheel changes the path of the rotation. In the case of forwarding direction equipment selection, the output gears will rotate in a direction opposite to the insight gears. But in the case of invert equipment selection, the rotation is usually in the same path 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 wants to change the gear would be the pressing of the clutch. After this comes the neutral state of the vehicle to be performed. Proper optimization of the engine’s speed is necessary.
2. After the neutral gear, one moves forwards to the first gear. The first equipment. This process is called dual clutching. Inefficiency in carrying out the above measures might result in a severe and gnashing sound.
Benefits and drawbacks of Constant Mesh Gearbox:
Advantages:
The first and foremost advantage of the constant gear mesh may be the usage of helical gears. The double helical gears and the helical gears are really beneficial due to their quieter operating capabilities
There are various conditions which can cause harm. Regarding constant mesh gearbox, any harm is suffered completely by the dog clutch teeth. One’s teeth belonging to the apparatus wheels remain intact. This is not the case for sliding mesh gear box.
The other gear boxes are noisy and create an undesired din.
Disadvantages:
It is less efficient compared to the others due to higher mesh teeth. Skill is necessary for it.
The double clutch mesh is necessary. This is required to possess the spinning motions of the shaft.
Application:
Some of the vehicles which use this type 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 provided on the main shaft i.electronic. one among the clutch gear and the second gear, and the other between the first gear 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 fixed with it.
As and when the left hand dog clutch is made to slide to the left by means of the apparatus change lever, it meshes with the clutch gear and the top speed equipment is obtained. When the still left 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 initial speed gear and reverse gear are obtained respectively.
In this kind 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 does not take place while engaging and disengaging.