Constant Mesh Gear Box
Constant mesh gearbox can be a type of Transmission where all or most of the gears are always in mesh with one another, instead of a sliding-gear transmission, where engagement can be obtained by sliding some of the gears along a shaft into mesh. In a constant-mesh manual gearbox, Gear construction and working of constant mesh gearbox ratios are selected by small Clutches that connect the various gear sets with their shafts to ensure that power is certainly transmitted through them. The next diagram shows the arrangement of a continuous mesh gear box
Construction and working of a constant mesh gear box
Constant gear 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 is used. the dog clutch is shifted by the seletor fork relocated by gear lever.To supply reverse gearing a idler gear is used.
When the apparatus lever is pushed, the apparatus selector fork pushes the dog clutch. Your dog clutch engages the apparatus and the output shaft, hence power from lay shaft now transmitted to result 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 and also the new shifting products named dog clutches square measure introduced which assists 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 comes with 4 forward speeds and 1 reverse manual transmission configuration.
Why will we wish Constant Mesh Transmission?
The introduction of initial transmission system i.electronic. sliding mesh transmitting was an excellent success in cars trade as presently there is a system which might provide needed torsion and speed ratios really want by the automobile to face the road challenges however still there have been several vital issues with this equipment that raised the question 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 special technique that wasn’t in any respect 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 dual engagement and disengagement of clutch for shifting one gear.
f i.electronic. once driver must shift the gear he initial presses the clutch pedal and generate 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 relevant gear will occur, save for he presses the clutch pedal and produce the apparatus lever to the required 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 than the meshing of these gears will cause breakage to the apparatus teethes or continuous wear and tear 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 different types of gears with both spur and helical gears like:
Clutch gear.
First gear.
Second gear.
Reverse gear.
WORKING PRINCIPLE:
In Continuous 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 the clutch equipment and the second gear; and the various other between your first gear and reverse gear. The main shaft is manufactured splined and all of the gears are absolve to move onto 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 left by making use 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 second speed gear is achieved. Similarly, by sliding the right-hand dog clutch left and correct, the first speed equipment and reverse equipment are obtained respectively In this type of gearbox, because all the gears are in continuous mesh, they are secure from being broken and unpleasant grinding sound does not happen while engaging and disengaging them.
Continuous mesh gearbox can be used for the smooth functioning of a car. They are accustomed to increase the rotating pressure (Torque); this is accompanied by a decrease in speed. It is a type of manual transmitting. The invention of earliest manual gear system could be traced back to the nineteenth century. There are multiple equipment ratios present which provides various torque and acceleration ratio. Additionally, the reverse mechanism can be present. This manual transmissions which are developed recently contain all of the gears mesh at any given point of time.
In specialized terms, it can be defined as a gearbox in which all the gears are often in circumstances of mesh. The gears remain fixed at their original positions. The gears will remain engaged all the time. Find out more about its construction, working, advantages, disadvantages and applications in this post.
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 main shaft. Remember according to the equipment ratio, the quickness of the counter shaft could be much less that the acceleration of the engine. The apparatus ratio can be explained as the ratio of the teeth of driven equipment to one’s teeth of the driver gear.
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 relative to 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. Utilizing a dog clutch, different gears can 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 more than one, the main shaft will continue to work at a speed that is slower compared to 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 power starts flowing and is split into four parts. Each component goes to among the output gears, namely first, second, third and fourth. Gear ratios can be obtained for each of them. This is often done by the proper sliding of dog clutch over one’s teeth of the chosen gearwheel. After this the road of the energy circulation 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 power is after that transmitted from the reverse gear to the reverse idler. The idler wheel changes the path of the rotation. Regarding forwarding direction gear selection, the output gears will rotate in a direction opposite to the input gears. But in the case of invert equipment selection, the rotation is certainly in the same path as the input shaft.
The steps are taken up to change any gear in the constant mesh gearbox system:
1. The first step 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 required.
2. After the neutral gear, one moves forward to the first gear. The first gear. This process is called double clutching. Inefficiency in performing the above techniques might result in a harsh and gnashing sound.
Benefits and drawbacks of Continuous 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 extremely beneficial owing to their quieter operating capabilities
There are various conditions which might cause harm. In the case of constant mesh gearbox, any damage is suffered entirely by your dog clutch teeth. One’s teeth belonging to the apparatus tires remain intact. This is not the case for sliding mesh equipment box.
The other equipment boxes are noisy and create an undesired din.
Disadvantages:
It is less efficient than the others because of higher mesh teeth. Skill is necessary for it.
The double clutch mesh is necessary. This is required to possess the spinning actions of the shaft.
Application:
Some of the vehicles which use this type of gearboxes are farm trucks, motorcycles, and weighty machinery.
In this kind of gearbox, all 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.e. one in between the clutch gear and the next gear, and the additional 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 and when the left hands dog clutch is made to slide to the left by means of the apparatus change lever, it meshes with the clutch gear and the very best speed gear is obtained. When the left hands dog clutch meshes with second equipment, the next gear is obtained.
Similarly, by sliding right hand dog clutch to the left and right, the 1st speed gear and reverse gear are obtained respectively.
In this type of gearbox, all the gears are in continuous mesh and hence for this reason, they are secure from being damaged and irritating grinding sound does not take place while engaging and disengaging.