Constant Mesh Gear Box
Constant mesh gearbox is certainly 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 is obtained by sliding some of the gears along a shaft into mesh. In a constant-mesh manual gearbox, Equipment ratios are selected by small Clutches that connect the various gear sets with their shafts so that power is certainly transmitted through them. The following diagram shows the set up of a continuous mesh gear box
Construction and operating 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, hence not transmitting power. The gears in both shafts are always meshed together.
To activate 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 invert gearing a idler gear is used.
When the construction and working of constant mesh gearbox apparatus lever is pushed, the apparatus selector fork pushes your dog clutch. Your dog clutch engages the gear and the output shaft, therefore power from lay shaft at this point transmitted to output shaft.
CONSTANT MESH GEARBOX
A constant mesh transmission is a type of manual transmission where sliding gears from the sliding mesh gearbox is replaced with the constantly meshed combines of gears and also the new shifting gadgets named dog clutches square measure introduced which helps in transmittal the required output to the the majority of 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 an excellent success in cars trade as presently there is a system which might provide needed torsion and speed ratios wish by the vehicle to face the road challenges nevertheless still there have been several vital problems with this equipment that raised the issue on its performance and responsibility. the problems long-faced were as follows-
The shifting of gears wasn’t an easy task since 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 since the name indicates that needed dual engagement and disengagement of clutch for shifting one particular gear.
f i.e. once driver must shift the gear he initial presses the clutch pedal and produce 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 in order that the meshing of relevant gear will happen, save for he presses the clutch pedal and generate the apparatus lever to the required gear and unleash the clutch pedal and finally the required gear is obtained.
Since the gears are to be meshed square measure in continuous rotation with a totally different speed compared to the meshing of these gears may cause breakage to the apparatus teethes or continuous deterioration is there.
The shifting of gears could be 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 Constant Mesh Gearbox gearbox, all gears of the primary shaft are in constantly meshed with the corresponding gears of the layshaft or countershaft. As well dog clutches are given on the primary shaft: one between your clutch equipment and the second gear; and the various other between your first gear and reverse 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 of the gears on the countershaft are permanently fixed with it.
When the left dog clutch was created 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 still left dog clutch meshes with the next gear on the main shaft, the next speed gear is achieved. Similarly, by sliding the right-hand dog clutch to the left and right, 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 damaged and unpleasant grinding sound does not occur while engaging and disengaging them.
Constant mesh gearbox is utilized for the smooth operating of an automobile. They are used to increase the rotating drive (Torque); that is accompanied by a decrease in speed. It is a kind of manual tranny. The invention of earliest manual equipment system can be traced back again to the nineteenth century. There are multiple equipment ratios present which gives various torque and quickness ratio. Along with this, 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 technical terms, it can be thought as a gearbox in which 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 all the time. Find out more about its construction, working, advantages, disadvantages and applications in this post.
Construction:
It really is made up of subsequent components:
1. Counter shaft or Lay Shaft:
This shaft is in direct connection with the clutch and the primary shaft. Remember according to the gear ratio, the speed of the counter shaft may be much less that the velocity of the engine. The gear ratio can be explained as the ratio of the teeth of driven equipment 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 can be used for the coupling of any two shafts. This is completed by interference. Using a dog clutch, numerous gears could 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 gear ratio is more than one, the main shaft will work at a quickness that is slower than the counter shaft, and vice versa. The set up of both reverse, in addition to forward gears, exists.
Working:
Forward gear selection:
From the input shaft, the power starts flowing and is divided into four parts. Each part goes to one of the result gears, namely initial, second, third and 4th. Gear ratios can be obtained for each of them. This can be done by the correct sliding of dog clutch over the teeth of the selected gearwheel. After this the path of the energy movement completes. This happens due to the locking movement 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 invert gear to the reverse idler. The idler wheel changes the direction of the rotation. In the case of forwarding direction gear selection, the result gears will rotate in a direction opposite to the input gears. But in the case of invert gear selection, the rotation is certainly in the same direction as the insight shaft.
The steps are taken up to change any gear in the continuous mesh gearbox system:
1. The first rung on the ladder when one wants to modify the gear will be the pressing of the clutch. Following 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 equipment. The first equipment. This process is known as 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 benefit of the constant gear mesh may be the utilization of helical gears. The double helical gears and the helical gears are really beneficial due to their quieter operating capabilities
There are numerous conditions which might cause harm. Regarding constant mesh gearbox, any harm is suffered completely by the 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 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 movements of the shaft.
Application:
Some of the vehicles designed to use this type of gearboxes are farm trucks, motorcycles, and weighty 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 given on the primary shaft i.electronic. one among the clutch gear and the second gear, and the various other between the first equipment and the reverse equipment.
The 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 was created to slide left by means of the gear shift lever, it meshes with the clutch gear and the very best speed equipment is obtained. When the still left hands dog clutch meshes with second equipment, the second gear is obtained.
Similarly, by sliding correct hand dog clutch left and right, the first speed gear and reverse gear are obtained respectively.
In this kind of gearbox, all of the gears are in continuous mesh and hence because of this, they are secure from being damaged and irritating grinding sound will not occur while engaging and disengaging.