construction and working of constant mesh gearbox

Constant Mesh Gear Box
Constant mesh gearbox is usually a type 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 can be 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 to their shafts to ensure that power can be transmitted through them. The following diagram shows the set up of a continuous 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 result shaft rotates freely without engaging with shaft, thus not transmitting power. The gears in both shafts are often meshed together.
To engage the gears with result shaft dog clutch is used. the dog clutch can be shifted by the seletor fork transferred by gear lever.To provide reverse 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 apparatus and the result shaft, therefore power from lay shaft today transmitted to output 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 as well as 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 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 transmitting was a great success in vehicles trade as currently there is a system which might offer needed torsion and swiftness ratios desire by the automobile to face the road challenges nevertheless still there have been several vital problems with this equipment that raised the query on its efficiency and responsibility. the problems long-faced were as follows-
The shifting of gears wasn’t a simple task since 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 since the name indicates that needed dual engagement and disengagement of clutch for shifting 1 gear.
f i.e. once driver must shift the apparatus he preliminary presses the clutch pedal and produce the gear to the neutral, than once again he releases the clutch pedal and accelerate so as to extend the acceleration of the lay-shaft in order that the meshing of applicable gear will take place, save for he presses the clutch pedal and produce the gear 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 compared to the meshing of these 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 various kinds 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 your clutch equipment and the second gear; and the additional between your first gear and reverse gear. The primary shaft is manufactured splined and all the gears are absolve to move onto it. Dog clutches can slide on the main shaft and rotates with it. All of the gears on the countershaft are permanently fixed with it.
When the left dog clutch was created to slide left by using the apparatus shift lever, it meshes with the clutch gear and the top speed gear is obtained. When the still left dog clutch meshes with the second gear on the main shaft, the next speed gear is achieved. Likewise, by sliding the right-hand dog clutch to the left and right, the first speed equipment 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 happen while engaging and disengaging them.
Constant mesh gearbox is utilized for the smooth operating of a car. They are accustomed to increase the rotating force (Torque); this is accompanied by a reduction in rate. It is a type of manual transmitting. The invention of earliest manual gear system can be traced back again to the nineteenth century. There are multiple equipment ratios present which gives various torque and velocity ratio. Along with this, the reverse mechanism is also present. This manual transmissions which are developed recently contain all of the gears mesh at any given point of time.
In specialized terms, it could be defined as a gearbox in which all of the gears are usually in a state of mesh. The gears stay fixed at their unique positions. The gears will remain engaged at all times. Find out more about its structure, 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 gear ratio, the swiftness of the counter shaft may be less that the velocity of the engine. The apparatus ratio can be defined as the ratio of one’s teeth of driven gear to one’s teeth of the driver equipment.
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 particular feature of continuous mesh gearbox. It is used for the coupling of any two shafts. This is performed by interference. Utilizing a dog clutch, numerous gears could be locked to the result and input shafts.
4. Gears:
The main work of the gears may be the transmission of power between your shafts. If the gear ratio is more than one, the main shaft will work at a velocity that is slower than the counter shaft, and vice versa. The arrangement of both reverse, in addition to forward gears, is present.
Working:
Forward gear selection:
From the input shaft, the power starts flowing and is split into four parts. Each part goes to one of the output gears, namely initial, second, third and fourth. Gear ratios can be acquired for each of these. This is often done by the proper sliding of dog clutch over one’s teeth of the chosen gearwheel. After this the path of the energy movement completes. This happens because of the locking movement of the output shaft.
Reverse gear selection:
The power will flow from the input shaft to the reverse gears. The power is after that transmitted from the invert gear to the reverse idler. The idler wheel changes the direction 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 reverse equipment selection, the rotation can be in the same direction as the insight shaft.
The steps are taken up to change any gear in the constant mesh gearbox system:
1. The first rung on the ladder when one wants to change the gear will be the pressing of the clutch. Following this comes the neutral state of the vehicle to be performed. Proper optimization of the engine’s speed is required.
2. After the neutral equipment, one moves forward to the first equipment. The first equipment. This process is known as double clutching. Inefficiency in performing the above guidelines might result in a severe and gnashing sound.
Benefits and drawbacks of Continuous Mesh Gearbox:
Advantages:
The first and foremost advantage of the constant gear mesh may be the utilization of helical gears. The dual helical gears and the helical gears are extremely beneficial due to their quieter operating capabilities
There are many conditions which can cause harm. Regarding constant mesh gearbox, any damage is suffered entirely by your dog clutch teeth. One’s teeth belonging to the apparatus wheels stay intact. This is simply not the case for sliding mesh equipment box.
The other gear boxes are noisy and create an undesired din.
Disadvantages:
It really is less efficient compared to the others due to higher mesh teeth. Skill is necessary for it.
The double clutch mesh is required. This is necessary to have the spinning actions of the shaft.
Application:
Some of the vehicles designed to use this type of gearboxes are farm trucks, motorcycles, and large machinery.
In this kind of gearbox, all of the gears of the primary 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.e. one in between the clutch gear and the next gear, and the additional between the first equipment and the reverse gear.
The 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 so when the left hand dog clutch is made to slide left by means of the gear change lever, it meshes with the clutch gear and the top speed equipment is obtained. When the left hand dog clutch meshes with second gear, the second gear is obtained.
Similarly, by sliding correct hand dog clutch left and right, the initial speed gear and reverse gear are obtained respectively.
In this type of gearbox, all of the gears are in continuous mesh and hence because of this, they are safe from being damaged and irritating grinding sound does not take place while engaging and disengaging.