Sliding mesh gearbox is a transmission system that consists of various sets of gears and shafts that are arranged together in an organized fashion and the shifting or meshing of different gear ratios is done by the sliding of gears towards the right and left over the splined shaft with the help of a gear lever operated by the driver.
An obsolete type of transmission or gearbox in which the gears on the layshaft are fixed to the shaft rigidly, whereas the gears on the main shaft can slide on it by means of splines but are otherwise permanent rotational mesh with the shaft. The figure below shows the arrangement of the sliding mesh gearbox.
Sliding Mesh Gearbox was the first gearbox or transmission system invented in the automobile. The first transmission system was given by French Inventors Louis-Rene and Emile Levassor who invented the world’s largest-ever transmission system with 3-speed sliding mesh transmission in 1894. The gear ratio is achieved by sliding the required gears to bring it with appropriate mating gears.
The main parts of the sliding mesh gearbox are:
The shaft is generally used to transmit the power from one end to another end. There are three types of shafts in the case of Sliding Mesh Gearbox.
Usually, two types of gears were used in the sliding mesh gearbox. They are: –
It is used to slide the gears in the main shaft to obtain the appropriate gear ratio. It is operated by the driver.
The gear connected to the clutch shaft also rotates. As the gear of the clutch shaft rotates, the layshaft gear which is connected to the clutch shaft gear also rotates but in opposite direction. So, the layshaft rotates due to the rotation of layshaft gear that is rigidly fixed in the layshaft.
Sliding mesh gearboxes are made with spur gear. The gears in the layshaft are rigidly fixed shafts. The gears in the main shaft alone can move along the spline. The selector fork moves the gear and moves the perfect mesh with the required gear in layshaft when the gear lever is shifted.
An idler gear is provided for reverse gearing. Thus, the power that forms the clutch shaft is transmitted to the main shaft through the layshaft.
Advantages of Sliding Mesh Gearbox: Its efficiency is more than a constant gearbox as only one gear is in mess, unlike the content mesh gearbox in which all gears are in constant mesh. Its manufacturing is easy as compared to a constant mesh gearbox.
the differences between a sliding mesh gearbox and a constant mesh gearbox are that the gears used in the constant mesh are helical whereas in sliding mesh they were spur. the layshaft is also always connected to the main shaft, meaning the gears always mesh.
A constant mesh gearbox is a type of transmission in which all forward gear pairs remain engaged. In a constant mesh gearbox, all gears are in the mesh all the time. The constant-mesh gearbox is a type of manual transmission in which the gears are meshed or fixed to their positions.
These are some disadvantages of Sliding Mesh Gearbox: The Mechanical Efficiency was very low in the case of Sliding Mesh Gearbox. The driver requires considerable skill for changing the gears because the gears of the main shaft and layshaft are away from each other.
Sliding gear is a power-transmission system in which any given pair of gears is engaged by sliding one axially into mesh with the other.
Sliding mesh gearboxes are made with spur gear. The gears in the layshaft are rigidly fixed shafts. The gears in the main shaft alone can move along the spline. The selector fork moves the gear and moves the perfect mesh with the required gear inlay shaft when the gear lever is shifted.
The shaft is generally used to transmit the power from one end to another end. There are three types of shafts in the case of Sliding Mesh Gearbox.
The idea of a transmission system is given by French inventors Louis-Rene and Emile Levassor who invented the world’s first-ever transmission system with 3-speed sliding mesh transmission in 1894 which was the boom in the automobile industry.
Open the driver’s side door and find the white card on the side of the door that is filled with small black lettering. This card contains specific details about the year the car was made, its transmission, engine specifications, and other details.
Not only does double-clutching allow you to put the transmission in first gear while you’re already moving, but it can also serve to extend the life of your synchronizers.
Disadvantages of Sliding Mesh Gearbox: Only spur gears can be used as gears are not in constant mesh-like constant-mesh gearbox in which helical or herringbone gears can be used.
The differences between a sliding mesh gearbox and a constant mesh gearbox are that the gears used in the constant mesh are helical whereas in sliding mesh they were spur. the layshaft is also always connected to the main shaft, meaning the gears always mesh.
| Parameter | Sliding Mesh Gear Box | Constant Mesh Gear Box |
| Construction | It consists of spur gear | It consists of helical gear |
| The main shaft gears are not in mesh constantly with the countershaft gears, which can slide and mesh. | All the gears on the main shaft are in constant mesh with the corresponding gears on the countershaft | |
| Selector fork unit is used in this gearbox for engaging the gear | A dog clutch unit is used in this gearbox for engaging the gears | |
| Torque Transmission | Low | High |
| Size | The size of the gearbox is large | The size of the gearbox is small compared to the sliding mesh gearbox. |
| Application | It is the oldest type of gearbox used in motor vehicles. | Constant-mesh gearbox has been used in 2&3-wheelers. |
Because the gears in a constant-mesh gearbox are constantly meshing, it’s less likely to damage the gear teeth, and there’s typically less wear on the gears. If a driver makes a “bad” change in gears, any damage that may occur will be limited to the dog clutch.
Sliding mesh gearboxes are made with spur gear. The gears in the layshaft are rigidly fixed shafts. The gears in the main shaft alone can move along the spline. The selector fork moves the gear and moves the perfect mesh with the required gear inlay shaft when the gear lever is shifted.
The gears of the main shaft slide over the shaft to mesh with the appropriate gears of the layshaft so that the required gear ratio is obtained. Spur gears have straight teeth that are produced parallel to the axis of the gear. These gears are a most economical type of gear but tend to vibrate and become noisy at high speed.
Helical gears are more durable than spur gears because the load gets distributed across more teeth. Hence, for a given load, the force will be spread out better than with a spur gear, resulting in less wear on individual teeth.
Disadvantages of Sliding Mesh Gearbox:
Main Shaft- It is the shaft used as an output shaft in a sliding mesh over which the sets of gears with internally splined grooves are arranged in an organized fashion. The outer surface of this shaft is made splined so that the gears can easily slide over this shaft in order to mesh with the appropriate gear.
