L.T Group has a comprehensive product and technology portfolio that focuses on 4 field of graphite – ultrafine particle graphite mould,graphite electrode, graphite crucible, as well as other products mainly made of graphite.
Graphite materials exhibit unique properties such as good electrical and thermal conductivity, heat and corrosion resistance, low friction, and reduced weight while at the same time maintaining high strength. Due to the shortage of energy and raw materials, our high performance products made from graphite are in increasingly high demand in industries. They also play a progressively important role in everyday life, thereby substituting traditional materials.
B:Pantograph skateboard application
The electrical equipment used by electric traction locomotives to obtain electrical energy from the catenary is installed on the roof of the locomotive or motor car. The pantograph can be divided into single-arm bow and double-arm bow, both of which are composed of a skateboard, upper frame, lower arm rod (lower frame for double-arm bow), underframe, bow lifting spring, transmission cylinder, support insulator and other components. The diamond-shaped pantograph is also called the CZPT pantograph. The smoothness of the load current passing through the contact surface of the contact wire and the pantograph slide is related to the contact pressure, transition resistance, and contact area between the slide and the contact wire, and depends on the interaction between the pantograph and the contact net.
C: Advantages of pantograph skateboard
The pantograph is to get electricity through the contact between the sliding plate and the contact net. The sliding plate is generally made of graphite and other materials, so the contact net wear is relatively small, and the sliding plate is easy to replace after it is worn, and the cost is low. The cycle is generally about 2 weeks, and it can be replaced once a month if the quality is good. However, the high-speed rail speed is 300 kilometers per hour, and the wind resistance of the pantograph is very large, so the design is very particular, not only to make it solid and reliable, but also to make it as light as possible.
D:Classification of pantograph charcoal skateboard
The pantograph sliding plate is a part of the pantograph head and directly contacts the contact wire. According to the material, it can be divided into pure metal sliding plate, powder metallurgy sliding plate, pure carbon sliding plate and immersed metal sliding plate.
Where the pantograph of electric locomotive contacts the wire, there are currently 3 materials in use in our country: 1. Pure carbon graphite slide plate 2. Metal-impregnated carbon slide plate 3. Powder metallurgy slide plate. However, due to the powder metallurgy sliding plate, the copper wire is seriously worn. Therefore, it has been basically replaced by the first 2 skateboards.
(1) Pure carbon graphite slide
A certain proportion of pitch coke, petroleum coke, graphite powder, carbon black or hard carbon is mixed with each other, and then pressed into a high-temperature sintering CZPT for roasting. The product can be applied after reprocessing. Although pure carbon slides are hard, brittle and easy to break, they are widely used because of their self-lubricating ability and good anti-wear properties.
(2) Metal-impregnated carbon skateboard
This type of skateboard not only combines the high mechanical strength and low resistance of powder metallurgy skateboards, but also combines the self-lubricating ability of pure carbon skateboards and the characteristics of less wear on overhead contact nets. In theory, it is the most ideal material for skateboards.
(3) Powder metallurgy skateboard
Using metal (iron, copper) raw materials and non-metallic powders (carbon, lead, molybdenum disulfide, etc.) as auxiliary lubricants, they are mixed with each other and then pressed into shape. After high temperature sintering, they are immersed in lubricating oil, and finally machined into shape. The processing process is similar to Ceramic firing, the surface hardness of the pantograph produced by it is high, and it is not easy to appear fracture and uneven wear. Compared with pure metal skateboards, it has its own lubrication effect.
The Benefits of Spline Couplings for Disc Brake Mounting Interfaces
Spline couplings are commonly used for securing disc brake mounting interfaces. Spline couplings are often used in high-performance vehicles, aeronautics, and many other applications. However, the mechanical benefits of splines are not immediately obvious. Listed below are the benefits of spline couplings. We’ll discuss what these advantages mean for you. Read on to discover how these couplings work.
Disc brake mounting interfaces are splined
There are 2 common disc brake mounting interfaces – splined and six-bolt. Splined rotors fit on splined hubs; six-bolt rotors will need an adapter to fit on six-bolt hubs. The six-bolt method is easier to maintain and may be preferred by many cyclists. If you’re thinking of installing a disc brake system, it is important to know how to choose the right splined and center lock interfaces.
The splines used for spline coupling in aircraft are highly complex. While some previous researches have addressed the design of splines, few publications have tackled the problem of misaligned spline coupling. Nevertheless, the accurate results we obtained were obtained using dedicated simulation tools, which are not commercially available. Nevertheless, such tools can provide a useful reference for our approach. It would be beneficial if designers could use simple tools for evaluating contact pressure peaks. Our analytical approach makes it possible to find answers to such questions.
The design of a spline coupling for aerospace applications must be accurate to minimize weight and prevent failure mechanisms. In addition to weight reduction, it is necessary to minimize fretting fatigue. The pressure distribution on the spline coupling teeth is a significant factor in determining its fretting fatigue. Therefore, we use analytical and experimental methods to examine the contact pressure distribution in the axial direction of spline couplings.
The teeth of a spline coupling can be categorized by the type of engagement they provide. This study investigates the position of resultant contact forces in the teeth of a spline coupling when applied to pitch diameter. Using FEM models, numerical results are generated for nominal and parallel offset misalignments. The axial tooth profile determines the behavior of the coupling component and its ability to resist wear. Angular misalignment is also a concern, causing misalignment.
In order to assess wear damage of a spline coupling, we must take into consideration the impact of fretting on the components. This wear is caused by relative motion between the teeth that engage them. The misalignment may be caused by vibrations, cyclical tooth deflection, or angular misalignment. The result of this analysis may help designers improve their spline coupling designs and develop improved performance.
CZPT polyimide, an abrasion-resistant polymer, is a popular choice for high-temperature spline couplings. This material reduces friction and wear, provides a low friction surface, and has a low wear rate. Furthermore, it offers up to 50 times the life of metal on metal spline connections. For these reasons, it is important to choose the right material for your spline coupling.
A spline coupler is a device used to connect splined shafts. A typical spline coupler resembles a short pipe with splines on either end. There are 2 basic types of spline coupling: single and dual spline. One type attaches to a drive shaft, while the other attaches to the gearbox. While spline couplings are typically used in racing, they’re also used for performance problems.
The key challenge in spline couplings is to determine the optimal dimension of spline joints. This is difficult because no commercial codes allow the simulation of misaligned joints, which can destroy components. This article presents analytical approaches to estimating contact pressures in spline connections. The results are comparable with numerical approaches but require special codes to accurately model the coupling operation. This research highlights several important issues and aims to make the application of spline couplings in high-performance vehicles easier.
The stiffness of spline assemblies can be calculated using tooth-like structures. Such splines can be incorporated into the spline joint to produce global stiffness for torsional vibration analysis. Bearing reactions are calculated for a certain level of misalignment. This information can be used to design bearing dimensions and correct misalignment. There are 3 types of spline couplings.
Major diameter fit splines are made with tightly controlled outside diameters. This close fit provides concentricity transfer from the male to the female spline. The teeth of the male spline usually have chamfered tips and clearance with fillet radii. These splines are often manufactured from billet steel or aluminum. These materials are renowned for their strength and uniform grain created by the forging process. ANSI and DIN design manuals define classes of fit.
Disc brake mounting interfaces
A spline coupling for disc brake mounting interfaces is a type of hub-to-brake-disc mount. It is a highly durable coupling mechanism that reduces heat transfer from the disc to the axle hub. The mounting arrangement also isolates the axle hub from direct contact with the disc. It is also designed to minimize the amount of vehicle downtime and maintenance required to maintain proper alignment.
Disc brakes typically have substantial metal-to-metal contact with axle hub splines. The discs are held in place on the hub by intermediate inserts. This metal-to-metal contact also aids in the transfer of brake heat from the brake disc to the axle hub. Spline coupling for disc brake mounting interfaces comprises a mounting ring that is either a threaded or non-threaded spline.
During drag brake experiments, perforated friction blocks filled with various additive materials are introduced. The materials included include Cu-based powder metallurgy material, a composite material, and a Mn-Cu damping alloy. The filling material affects the braking interface’s wear behavior and friction-induced vibration characteristics. Different filling materials produce different types of wear debris and have different wear evolutions. They also differ in their surface morphology.
Disc brake couplings are usually made of 2 different types. The plain and HD versions are interchangeable. The plain version is the simplest to install, while the HD version has multiple components. The two-piece couplings are often installed at the same time, but with different mounting interfaces. You should make sure to purchase the appropriate coupling for your vehicle. These interfaces are a vital component of your vehicle and must be installed correctly for proper operation.
Disc brakes use disc-to-hub elements that help locate the forces and displace them to the rim. These elements are typically made of stainless steel, which increases the cost of manufacturing the disc brake mounting interface. Despite their benefits, however, the high braking force loads they endure are hard on the materials. Moreover, excessive heat transferred to the intermediate elements can adversely affect the fatigue life and long-term strength of the brake system.