Constant Mesh Gear Box
Constant mesh gearbox is definitely a kind of Transmission where all or most of the gears are always in mesh with each other, as opposed to 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 chosen by small Clutches that connect the many gear sets with their shafts to ensure that power can be transmitted through them. The following diagram shows the arrangement of a constant mesh gear box
Construction and operating of a construction and working of constant mesh gearbox Continuous mesh gear box
Constant equipment mesh gearbox employed helical gears for power transmission. The gears are rigidly fixed 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 constantly meshed together.
To engage the gears with output shaft dog clutch is used. the dog clutch can be shifted by the seletor fork moved by gear lever.To supply invert gearing a idler gear is used.
When the gear lever is pushed, the apparatus selector fork pushes the dog clutch. The dog clutch engages the apparatus and the result shaft, thus power from lay shaft today transmitted to result shaft.
CONSTANT MESH GEARBOX
A continuous mesh transmission is a kind 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 assists in transmittal the desired output to the many shaft by creating contact with the acceptable pair of the meshed gears.
A constant mesh transmission typically includes 4 forward speeds and 1 reverse manual tranny configuration.
Why will we wish Constant Mesh Transmission?
The introduction of initial transmission system i.electronic. sliding mesh transmitting was a great success in vehicles trade as presently there was a system which can provide needed torsion and swiftness ratios really want by the vehicle to face the road challenges nevertheless still there were several vital problems with this equipment that raised the question on its effectiveness and responsibility. the problems 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 necessary for driving 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 particular gear.
f i.e. once driver needs to shift the apparatus he initial presses the clutch pedal and create the gear to the neutral, than once again he releases the clutch pedal and accelerate so as to extend the quickness of the lay-shaft to ensure that the meshing of relevant gear will happen, save for he presses the clutch pedal and generate the apparatus lever to the desired equipment 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 than the meshing of these gears may cause breakage to the gear 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 Continuous 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 main shaft: one between your clutch equipment and the second gear; and the various other between the first gear and reverse gear. The main shaft is made splined and all of the gears are absolve to move on 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 help of the apparatus shift lever, it meshes with the clutch gear and the very best speed gear is obtained. When the remaining dog clutch meshes with the second gear on the main shaft, the next speed equipment is achieved. Likewise, by sliding the right-hand dog clutch left and correct, the first speed equipment and reverse gear are acquired respectively In this type of gearbox, because all of the gears are in constant mesh, they are secure from being broken and unpleasant grinding audio does not take place while engaging and disengaging them.
Constant mesh gearbox can be used for the smooth working of an automobile. They are accustomed to increase the rotating power (Torque); this is accompanied by a decrease in swiftness. It is a type of manual transmission. The invention of earliest manual equipment system could be traced back again to the nineteenth century. There are multiple gear ratios present which gives various torque and velocity ratio. Additionally, the reverse mechanism can be 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 thought as a gearbox where all of the gears are always in a state of mesh. The gears remain fixed at their primary positions. The gears will remain engaged at all times. Learn more about its building, working, advantages, drawbacks and applications in this post.
Construction:
It is made up of following 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 acceleration of the counter shaft could be less that the acceleration of the engine. The apparatus ratio can be defined 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 vehicle. The power is manufactured available to the primary shaft through the gears from the counter shaft. That is done in accordance with 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 done by interference. Using 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 the shafts. If the gear ratio is several, the main shaft will work at a acceleration that is slower compared to the counter shaft, and vice versa. The arrangement of both reverse, in addition to 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 one of the result gears, namely first, second, third and 4th. Gear ratios can be acquired for each of them. This could be done by the proper sliding of dog clutch over the teeth of the selected gearwheel. After this the path of the energy stream completes. This happens due to the locking motion of the result shaft.
Reverse gear selection:
The power will flow from the input shaft to the reverse gears. The energy is after that transmitted from the reverse gear to the invert idler. The idler wheel will change the path of the rotation. In the case of forwarding direction equipment selection, the result gears will rotate in a path opposite to the input gears. However in the case of invert equipment selection, the rotation can be in the same direction as the input shaft.
The steps are taken to change any gear in the constant mesh gearbox system:
1. The first rung on the ladder when one really wants to modify the gear would be the pressing of the clutch. Following this comes the neutral state 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 equipment. The first gear. This process is called dual clutching. Inefficiency in performing the above methods might result in a harsh and gnashing sound.
Advantages and Disadvantages of Continuous Mesh Gearbox:
Advantages:
The first and foremost advantage of the constant gear mesh may be the usage of helical gears. The dual helical gears and the helical gears are really beneficial due to their quieter operating capabilities
There are many conditions which might cause harm. Regarding constant mesh gearbox, any damage is suffered entirely by your dog clutch teeth. The teeth belonging to the gear wheels stay intact. This is not the case for sliding mesh equipment box.
The other equipment boxes are noisy and create an undesired din.
Disadvantages:
It really is less efficient compared to the others because of higher mesh teeth. Skill is required for it.
The dual clutch mesh is necessary. This is necessary 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 weighty machinery.
In this kind of gearbox, all the gears of the main shaft are in continuous 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 equipment and the second gear, and the additional between the first equipment and the reverse equipment.
The dog clutch can slide on the shaft and rotate with it. While, all the gears on the counter shaft are rigidly set with it.
As and when the left hands dog clutch is made to slide left by means of the gear change lever, it meshes with the clutch equipment and the very best speed gear is obtained. When the still left hands dog clutch meshes with second gear, the next gear is obtained.
Similarly, by sliding correct hand dog clutch 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 because of this, they are safe from being damaged and irritating grinding sound will not occur while engaging and disengaging.