Constant Mesh Gear Box
Constant mesh gearbox can be a type of Transmission in which 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 some of the gears along a shaft into mesh. In a constant-mesh manual gearbox, Gear ratios are selected by small Clutches that connect the various gear sets with their shafts so that power is definitely transmitted through them. The following diagram shows the set up of a continuous mesh gear box
Construction and working of a constant mesh gear box
Constant equipment 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, thus not really transmitting power. The gears in both shafts are at all times meshed together.
To activate the gears with output shaft dog clutch is used. the dog clutch is usually shifted by the seletor fork transferred by gear lever.To provide reverse gearing a idler equipment is used.
When the gear lever is pushed, the gear selector fork pushes your dog clutch. Your dog clutch engages the apparatus and the result shaft, hence power from lay shaft at this point transmitted to output shaft.
CONSTANT MESH GEARBOX
A constant 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 sq . measure introduced which assists in transmittal the required output to the most shaft by creating contact with the acceptable pair of the meshed gears.
A continuous 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 tranny was a great success in cars trade as presently there is a system which can offer needed torsion and swiftness ratios need by the vehicle to face the street challenges however still there were several vital issues with this equipment that raised the question 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 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 double 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 produce the apparatus to the neutral, than once again he releases the clutch pedal and accelerate so as to extend the speed of the lay-shaft to ensure that the meshing of applicable gear will occur, save for he presses the clutch pedal and create the gear lever to the required gear and unleash the clutch pedal and at last 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 will cause breakage to the apparatus teethes or continuous deterioration 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 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 various other between your first gear and reverse gear. The main 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 the gears on the countershaft are completely fixed with it.
When the left dog clutch is made to slide to the left with the help of the gear shift lever, it meshes with the clutch gear and the very best speed gear is obtained. When the left dog clutch meshes with the next 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 gear and reverse gear are obtained respectively In this kind of gearbox, because all of the gears are in constant mesh, they are safe from being damaged and unpleasant grinding audio does not take place while engaging and disengaging them.
Continuous mesh gearbox is utilized for the smooth operating of an automobile. They are used to increase the rotating push (Torque); that is accompanied by a decrease in speed. It is a type of manual transmission. The invention of earliest manual gear system can be traced back again to the nineteenth century. There are multiple equipment ratios present which provides various torque and rate ratio. Additionally, the reverse mechanism can be present. This manual transmissions which are developed recently contain all the gears mesh at any given point of time.
In specialized terms, it can be thought as a gearbox where all of the gears are usually in circumstances of mesh. The gears remain fixed at their original positions. The gears will remain engaged at all times. Learn 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 primary shaft. Keeping in mind according to the equipment ratio, the rate of the counter shaft could be less that the rate of the engine. The gear ratio can be defined as the ratio of one’s teeth of driven gear to the teeth of the driver equipment.
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 relative to the gear ratio.
3. Dog clutch:
Dog clutch is special feature of constant mesh gearbox. It is utilized for the coupling of any two shafts. That is performed by interference. Using a dog clutch, different gears can 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 several, the main shaft will work at a rate that is slower than the counter shaft, and vice versa. The arrangement of both reverse, as well as 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 among the output gears, namely 1st, second, third and fourth. Gear ratios can be obtained for each of these. This can be done by the correct sliding of dog clutch over one’s teeth of the chosen gearwheel. After this the path of the energy movement completes. This happens due to the locking movement of the result shaft.
Reverse gear selection:
The energy will flow from the input shaft to the reverse gears. The power is then 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 gear selection, the output gears will rotate in a direction opposite to the input gears. But in the case of invert gear selection, the rotation is definitely 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 step when one really wants to modify the gear will be the pressing of the clutch. After this comes the neutral state of the automobile to be performed. Proper optimization of the engine’s speed is necessary.
2. After the neutral gear, one moves ahead to the first gear. The first equipment. This process is known as double clutching. Inefficiency in executing the above actions might lead to a severe and gnashing sound.
Benefits and drawbacks of Continuous Mesh Gearbox:
Advantages:
The first and foremost advantage of the continuous gear mesh may be the utilization of helical gears. The double helical gears and the helical gears are extremely beneficial owing to their quieter operating capabilities
There are various conditions which might cause harm. Regarding continuous mesh gearbox, any damage is suffered completely by the dog clutch teeth. The teeth belonging to the gear tires stay intact. This is simply not the case for sliding mesh equipment box.
The other equipment boxes are noisy and create an undesirable din.
Disadvantages:
It really is less efficient than the others because of higher mesh teeth. Skill is necessary for it.
The dual clutch mesh is required. This is necessary to have the spinning movements of the shaft.
Application:
A few of the vehicles which use this kind of gearboxes are farm trucks, motorcycles, and weighty machinery.
In this kind of gearbox, all 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 in between the clutch equipment and the second gear, and the other between the first gear 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 hand dog clutch was created to slide left by means of the gear shift lever, it meshes with the clutch equipment and the top speed gear is obtained. When the remaining hand dog clutch meshes with second equipment, the second gear is obtained.
Similarly, by sliding right 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 for this reason, they are secure from being damaged and irritating grinding sound will not take place while engaging and disengaging.
