Refuse to break the iron plate! Give a positive name to the leaf spring
When it comes to leaf springs, I believe many car enthusiasts who have come into contact with them will not be unfamiliar. Leaf springs are one of the most common spring suspension components in the current truck market. They connect the frame (or body) elastically, playing a role in elastic connection between the axle and frame, thereby reducing the discomfort caused by uneven roads during vehicle operation and ensuring the normal driving of the car, And maintain a certain level of stability and comfort; However, in the eyes of many non industry friends, leaf springs are often intentionally transformed into pieces or even piles of broken iron plates, which is actually a misconception. Today, Xiaoyuan will share with everyone the correct knowledge about leaf springs.
General concepts and functions of leaf springs
From the self definition of leaf springs, leaf springs, also known as leaf springs, are one of the most widely used elastic components in automotive suspension; Suspension structure is a widely used system structure, which is usually composed of elastic components (various springs), guiding mechanisms (various arms and beams), and shock absorbers (various shock absorbers); And elastic components can be divided into forms such as leaf springs, air springs, spiral springs, and torsion bar springs, among which the form of leaf springs is the most common.
The shape of the steel plate spring commonly used on trucks adopts a symmetrical cross-section structure, which is usually composed of several steel plate spring plates with different lengths, radius of curvature, thickness, or thickness, to form a similar strong elastic beam; The suspension structure of steel plate springs mainly consists of steel plate springs, central bolts, spring clips, rolling ears, and sleeves as component structural assemblies.
Currently, many unloading trucks on the market use non independent suspensions with leaf springs, which are fixed to the axle through the middle U-shaped bolts and the upper and lower cover plates and lower support plates. The front rolling ears are connected to the bracket through pins, and the rear ears are connected to the swinging lifting ears on the frame through pins, forming a movable hinge support point. However, due to the large changes in mass of the unloading truck suspension, a secondary leaf spring assembly is generally installed above the main leaf spring assembly, So as to play a corresponding role according to different loads.
On commercial vehicles, steel plate springs are generally used as the main elastic components, mainly because they can connect the axle and body well. The spring plates transmit the impact force on the wheels to the frame through relative sliding and friction, playing a buffering and shock absorption role; The main task of a steel plate spring is to transmit all the forces and moments acting between the wheels and the vehicle body, alleviate the impact load transmitted by the bumpy road surface to the vehicle body and the vibration of the load-bearing system caused by it, thereby ensuring the normal driving of the vehicle. In addition to its shock absorption function, the steel plate spring also serves as a guiding and shock absorption mechanism during the driving process of the vehicle body, controlling the specified trajectory of the vehicle wheels and ensuring good operability and stability.
● Classification of steel plate springs with multiple or fewer types
The existing leaf springs on the market are mainly divided into two forms: multi leaf springs and few leaf springs. Based on the thickness and structural differences of the spring plates, multi leaf springs are mainly suitable for heavy-duty vehicles, while few leaf springs are mainly used for light vehicles.
1. Multi leaf spring steel plate spring
Multi leaf spring steel plate springs are mostly found in heavy-duty trucks, consisting of multiple steel plates stacked in an inverted triangular shape. Each spring has the same width and unequal length, forming a complete multi leaf spring; Among them, the number of steel plates for multiple steel plate springs is closely related to the mass of the supported vehicle. If the number of steel plates is thicker and shorter, the spring stiffness will be greater. In other words, the number of steel plates is directly related to the shock absorption effect. It is necessary to design an appropriate steel plate thickness based on the specific vehicle model.
Advantages and disadvantages of multi leaf springs:
Multi leaf springs have simple structure, reliable performance, easy manufacturing, low cost, convenient maintenance and repair, small changes in wheel alignment parameters, and minimal tire disc wear;
However, with the increase of usage time, multiple steel plate springs will generate sliding friction between each other, resulting in a certain amount of noise. However, due to the heavy weight of the vehicle parts, the springs are difficult to design as soft, and friction can also cause deformation of the springs, affecting the smooth driving of the vehicle.
2. Small leaf spring steel plate spring
Fewer leaf springs are commonly found in light and heavy vehicles, and are usually composed of rigid plates of equal width, thin at both ends, and thick in the middle. The interface of the steel plate changes greatly, gradually changing from the middle to the two ends, making the rolling process more complex. Compared with multi leaf springs, fewer leaf springs reduce weight by about 50%, thereby reducing fuel consumption.
Advantages and disadvantages of fewer leaf springs:
Compared with multi leaf springs, a few leaf spring can reduce friction between the plates and reduce the noise caused; In addition, the design of the few leaf spring also reflects the popular lightweight concept today, with small weight in the load-bearing part, good smoothness, stability, and passability, improving the smoothness of vehicle driving and driving comfort. However, fewer leaf springs have higher requirements for processing cross-sectional technology, complex structures, high manufacturing costs, and inconvenient maintenance.
Other types of springs
Advantages of steel plate springs: In terms of structure, the composition of steel plate springs is simple, the manufacturing cost is relatively low, and it is easy to repair. It not only has the function of shock absorption and buffering, but also has the function of a guiding mechanism; Leaf springs are widely used in trucks, buses, off-road vehicles, vans, and pickup trucks.
Disadvantages of steel plate springs: This structure is only suitable for non independent suspensions and has certain limitations in use; As the name suggests, a steel plate spring is composed of a combination of steel plates, with high overall quality and stiffness. Its comfort is poor, and its longitudinal dimensions are too long, which is not conducive to shortening the front and rear suspensions of the car. The steel plate spring pins at the connection with the frame are also prone to wear and tear.
Coil spring
Airbag suspension
Of course, automotive suspension springs are not limited to only one type of steel plate spring, for example, spiral springs are widely used as elastic components for independent suspension of passenger cars; Gas springs can easily lift and lower the chassis, improving driving stability, and are not only suitable for high-end sedans, but also common in airbag suspensions on many commercial vehicles today.
Rubber spring
In addition to the above, there is also a torsion bar spring that is easy to achieve automatic height adjustment of the vehicle body. Its spring element structure is relatively simple and does not require lubrication. It can also be adjusted by adjusting the installation angle of the fixed end of the torsion bar spring. In addition, there are rubber springs, which will not be introduced here. In summary, different vehicle elastic components may have structural differences to adapt to different vehicle environments.
● Precautions for maintenance and upkeep
During the use of the vehicle by fellow car enthusiasts, sometimes the steel plate spring may be damaged or broken. It is normal for the steel plate spring to break after being used for too long. However, if the damage occurs early, most of the cases are still caused by abnormal use, improper or lack of maintenance of the components. Below, Xiaoyuan has summarized several precautions for car enthusiasts when using steel plate springs.
1. Car enthusiasts should pay more attention to the maintenance of the steel plate spring in their daily lives, and regularly lubricate it to prevent shock absorber failure caused by insufficient lubrication.
2. During maintenance, it is also important to pay attention to the tightening of the riding bolts and center bolts to prevent damage to the steel plate spring due to loose bolts.
3. The rated load capacity of a vehicle is largely related to the number of majestic steel plates. When a vehicle is frequently overloaded or eccentrically loaded, the fatigue strength of the steel plate spring will decrease, and the service life of the steel plate spring will also be relatively shortened.
4. If you want to extend the service life of the steel plate spring, you should pay attention to avoiding driving too fast, especially when driving on rough roads. Excessive speed can easily cause damage to the steel plate spring due to accelerated fatigue.
In addition, when driving, it is necessary to minimize emergency braking as much as possible, otherwise the steel plate spring will bear excessive bending and tensile stress; When turning, if the speed is too fast, it will also increase the load on the outer steel plate spring, causing acceleration damage to the steel plate spring.
● Postscript:
Through the brief introduction to leaf springs above, I believe everyone has a certain level of understanding of their structural principles and advantages and disadvantages; Leaf springs can be said to be the most widely used elastic component in commercial vehicles, which can play a buffering and shock absorption role, and their quality directly affects the safety of vehicle driving.
Finally, I hope that all car enthusiasts and drivers can use the steel plate spring correctly in their daily driving work, and do a good job in the daily repair and maintenance of the steel plate spring, with more consideration for driving safety.
