sub-frame can be regarded as the skeleton of the front and rear axle is part of the front and rear axle. The sub-frame is not a complete frame, but the front and rear axle bearing, suspension bracket so that the axle, and then connected to the suspension “frame n” through it, known as the “sub-frame” on the diet. The role of sub-frame is blocking vibration and noise, reduce its direct access to the cabin, so mostly in luxury cars and sport utility vehicles and some car was also fitted with engine sub-frame. No sub conventional monocoque frame, which is suspended directly connected to the steel body. Therefore, the front and rear axle suspension rocker arm mechanism are parts, not assembly. After the birth of the sub-frame, front and rear suspension can be assembled on the first subframe, constitute a axle assembly, then the assembly is installed along the vehicle body.
1. Noun sub-frame
sub-frame can be regarded as the skeleton of the front and rear axle is part of the front and rear axle. The sub-frame is not a complete frame, but the front and rear axle bearing, suspension bracket so that the axle, and then connected to the suspension “frame n” through it, known as the “sub-frame” on the diet. The role of sub-frame is blocking vibration and noise, reduce its direct access to the cabin, so mostly inLuxury cars and sport utility vehicles, but also for some car engines mounted on the sub-frame. No sub conventional monocoque frame, which is suspended directly connected to the steel body. Therefore, the front and rear axle suspension rocker arm mechanism are parts, not assembly. After the birth of the sub-frame, front and rear suspension can be assembled on the first subframe, constitute a axle assembly, then the assembly is installed along the vehicle body.
2. The principle role of the sub-frame
This sub-frame with a suspension assembly, in addition to the design, installation can bring various advantages beyond convenience and, most important thing is for comfort and suspension stiffness increased.
is not directly connected to the car engine body rigidity. But it is connected by a suspension to the vehicle body. We often see that the suspension of the vehicle body and the engine cushion rubber connection. As technology advances, more and more types of suspension, high-end vehicles with hydraulic suspension. Suspended role is to isolate engine vibration. That role under suspension, engine vibration can be transmitted to the cockpit as little as possible. Since the engine speed range in each segment has a different vibration characteristics, so good suspension means to effectively shield the respective vibration speed range section. That’s why we open some of the better matching of high-end car, whether the engine is 2000 rpm or 5000 rpm in, while driving reason not feel too much engine vibration.
the point of attachment of the subframe and the vehicle body like the engine mount the same. Usually a need to connect the axle assembly and the vehicle body by a four point suspension, So it can guarantee its joint stiffness, but also have a good vibration isolation effect.
This suspension can always be reduced in five levels of the vibration with the incoming subframe. The first stage is absorbed by the soft rubber shock deformation of the tire of the table, which a large amount of deformation capable of absorbing high-frequency vibration, the second-stage shock absorbing deformation of the tire as a whole, which mainly absorb a slightly higher level than the first road vibration, such as vibration caused by stones and the like. The third stage is suspended on the vibration isolation rubber bush within each of the rocker arm connection point, this part mainly reduce the impact of the suspension assembly. The fourth stage is a suspension of up and down movement, this movement is mainly absorb long-wave shock, vibration is caused when too over-ditch threshold. Level 5 is a shock-absorbing suspension sub-frame, where the main absorption stage is not completely shield the first four vibration.
For the sub-frame so that, in the performance of the main object is to reduce the incoming road vibration, and increased connection stiffness of the suspension system, so the sub-vehicle equipped with frame chassis car driver will feel very solid, very compact. The suspension subframe hardness setting is also facing suspension tuning as the same can not avoid a contradiction. If the suspension subframe design is soft, it can be well isolated from vibration generated when cars, but too soft suspension sub-frame design will bring greater movement of deformation during high-speed turns, which can cause tires inaccurate positioning, thereby reducing the handling stability. Stiffer subframe mount, can bring very high connection stiffness, but very limited noise vibration isolation. So engineers tend to choose rubber gasket suitable for positioning stiffness and use models in the design and matching sub-frame.
3. Advantage of the sub-frame
advantages
1. The sub-frame can bring a good stiffness of suspension connecting
2 can be isolated from road vibration brings good comfort [123 ]
3. the cartridge into suspension member, increasing the versatility of the suspension, reduce development costs.
4. The cartridge member easy to install, reduces assembly costs.
4. The disadvantage of the sub-frame
drawbacks
1. Subframe large vehicle weight increases, although the use of aluminum alloy can be However, the cost will be reduced to increase the weight.
2. Lowered driving stability, steering feel does not directly rarely used on the car.